@conference {cGiardinaa, title = {Anatomically Guided 3D Diffusion Models for Synthetic Prostate MRI Generation}, booktitle = {5th Deep Generative Models Workshop - MICCAI 2025}, year = {In Press}, author = {Claudia Giardina and Sigrid Vila-Bagaria and Carlos Arbon{\'e}s and M. Pard{\`a}s and Ver{\'o}nica Vilaplana} } @conference {cJimenezb, title = {Segmenting Invasive and In Situ Carcinoma in Breast WSIs with a Pretrained Histopathology Transformer}, booktitle = {2nd Deep Breast Workshop on AI and Imaging for Diagnostic and Treatment Challenges in breast care - MICCAI2025}, year = {In Press}, author = {Lauren Jimenez and Felip Vilardel and Ana Petit and Eduard Dorca and Teresa Soler-Mons{\'o} and Irma Ramos-Oliver and Laura Pons and Pedro L. Fern{\'a}ndez and Laia Adalid-Llansa and Daniel Mata and Lourdes Salazar-Huayna and Casas, J. and Ver{\'o}nica Vilaplana} } @article {aSegui, title = {DASPack: Controlled Data Compression for Distributed Acoustic Sensing}, journal = {Geophysical Journal International}, volume = {244}, year = {2026}, month = {01/2026}, abstract = {

We present DASPack, a high-performance, open-source compression tool specifically designed for distributed acoustic sensing (DAS) data. As DAS becomes a key technology for real-time, high-density, and long-range monitoring in fields such as geophysics, infrastructure surveillance, and environmental sensing, the volume of collected data is rapidly increasing. Large-scale DAS deployments already generate hundreds of terabytes and are expected to increase in the coming years, making long-term storage a major challenge. Despite this urgent need, few compression methods have proven to be both practical and scalable in real-world scenarios. DASPack is a fully operational solution that consistently outperforms existing techniques for DAS data. It enables both controlled lossy and lossless compression by allowing users to choose the maximum absolute difference per datum between the original and compressed data. The compression pipeline combines wavelet transforms, linear predictive coding, and entropy coding to optimise efficiency. Our method achieves up to 3X file size reductions for strain and strain rate data in lossless mode across diverse datasets. In lossy mode, compression improves to 6X with near-perfect signal fidelity, and up to 10X is reached with acceptable signal degradation. It delivers fast throughput (100{\textendash}200 MB/s using a single-thread and up to 750 MB/s using 8-threads), enabling real-time deployment even under high data rates. We validated its performance on 15 datasets from a variety of acquisition environments, demonstrating its speed, robustness, and broad applicability. DASPack provides a practical foundation for long-term, sustainable DAS data management in large-scale monitoring networks.

}, keywords = {Distributed Acoustic Sensing, image processing, Probability distributions, Time-series analysis, Wavelet transform}, doi = {https://doi.org/10.1093/gji/ggaf397}, author = {Segu{\'\i}, Aleix and Ugalde, Arantza and Fichtner, Andreas and Ventpsa, Sergi and Morros, J.R.} } @inbook {bJimenez, title = {Breast Cancer Molecular Subtyping from H\&E Whole Slide Images using Foundation Models and Transformers}, booktitle = {Artificial Intelligence and Imaging for Diagnostic and Treatment Challenges in Breast Care}, volume = {15451}, number = {Lecture Notes in Computer Science}, year = {2025}, publisher = {Springer}, organization = {Springer}, abstract = {

This study tackles the challenge of classifying breast cancer molecular subtypes using H\&E-stained Whole Slide Images (WSI), avoiding the cost and labor limitations of the commonly used immunohistochemistry. We leverage the Attention-Challenging Multiple Instance Learning framework and introduce a variant, ACTrans, which utilizes a transformer aggregator for improved performance. We also compare two publicly available foundation feature extractors pre-trained on large pathology datasets. A comparison of the impact of two different patch sizes at two different magnifications is made. The results obtained in our in-house dataset demonstrate that ACTrans outperforms existing methods, particularly with the UNI model at lower resolutions and larger patch sizes. In this setting, ACTrans achieves an average F1 score of 0.687, a precision of 0.755, a recall of 0.667, and an AUC of 0.812. Furthermore, these approaches enhance interpretability when displaying the attention weights. This method can potentially advance breast cancer diagnostics by leveraging the rich information within H\&E-stained WSIs.

}, author = {Lauren Jimenez and Carlos Hernandez and Ver{\'o}nica Vilaplana} } @conference {cPina25, title = {Cell Detection with Transformers {\textendash} A Paradigm Shift from Segmentation to Detection in Digital Pathology}, booktitle = {21st European Congress on Digital Pathology}, year = {2025}, month = {06/2025}, abstract = {

Cell nuclei detection and classification are fundamental tasks in digital pathology, enabling biomarker quantification and tumor microenvironment analysis. Although the clinically relevant objective is to detect and classify individual cells, these tasks are typically addressed using segmentation-based methods. While effective, segmentation introduces significant computational overhead. To overcome these limitations, we propose CellNuc-DETR, a transformer-based detection model that directly detects and classifies cells, offering a more efficient and scalable alternative to segmentation-based approaches

}, author = {Oscar Pina and Eduard Dorca and Ver{\'o}nica Vilaplana} } @article {aHernandeza, title = {Comparative Analysis and Interpretability of Survival Models for Melanoma Prognosis}, journal = {Computers in Biology and Medicine}, volume = {190}, year = {2025}, month = {05/2025}, abstract = {

The increasing incidence of cutaneous melanoma highlights the critical need for precision medicine to optimize treatment strategies and improve patient outcomes. This study evaluated and compared the performance and interpretability of various survival models for melanoma patients. We analyzed survival outcomes, including overall survival (OS), specific survival (SS), and disease-free survival (DFS), using the Xarxa Melanoma database, which comprises data from over 9,000 patients across 19 hospitals collected over a decade. The performance of Cox Proportional Hazards, Random Survival Forest, XGBoost, DeepSurv, and DeepHit models was assessed using the Concordance Index (C-Index), time-dependent Area Under the Curve (tdAUC), ROC-AUC, and Inverse Brier score. Our analysis showed that the Random Survival Forest outperformed the other methods, achieving C-Index scores of 0.846 for OS, 0.869 for SS, and 0.846 for DFS. Furthermore, by applying an interpretability method specifically designed for survival analysis, we identified histological subtypes associated with poor prognoses. Additionally, this study reaffirms the established importance of the Breslow index as a key prognostic factor in melanoma survival prediction.

}, issn = {0010-4825}, doi = {https://doi.org/10.1016/j.compbiomed.2025.110027}, url = {https://www.sciencedirect.com/science/article/pii/S0010482525003786?via\%3Dihub}, author = {Carlos Hernandez and Sebastian Podlipnik and Joan Ficapal and Susana Puig and Josep Malvehy and Ver{\'o}nica Vilaplana} } @phdthesis {dPina25, title = {From pixels to graphs: cell-based digital pathology image analysis}, volume = {PhD}, year = {2025}, month = {06/2025}, type = {PhD Thesis}, abstract = {

Histopathology is the gold standard for cancer diagnosis, where pathologists examine tissue samples to assess cellular morphology, tissue architecture, and biomarker expression. The digitization of histological slides has enabled the application of artificial intelligence to assist in this process. However, deploying deep learning models in pathology remains challenging due to the gigapixel-scale nature of whole slide images, variability introduced by staining protocols and tissue morphology, and the scarcity of high-quality annotations. This thesis focuses on the development of deep learning methodologies for the identification and characterization of cells in histopathological slides, addressing these core challenges. Inspired by the way pathologists assess slides, the proposed methods target both individual cells and their spatial organization within the tissue. A transformer-based model, CellNuc-DETR, is introduced for efficient cell nuclei detection and classification, achieving state-of-the-art performance while significantly reducing inference time. To address annotation scarcity in immunohistochemistry, the model is adapted using unsupervised domain adaptation techniques, enabling knowledge transfer from hematoxylin and eosin-stained slides without requiring annotated immunohistochemistry data. To incorporate broader spatial context into cell classification, the thesis explores graph-based representations of histological tissue. It proposes a novel graph construction strategy that integrates both cell-level and patch-level nodes, enabling the fusion of cellular features with visual and contextual information in a scalable manner. To support annotation-efficient learning, the thesis introduces Regularized Graph Infomax, a self-supervised learning algorithm designed for representation learning on graphs without manual annotations. This algorithm is then applied to the proposed cell{\textendash}patch graphs to enable efficient, large-context cell classification with minimal supervision. Finally, the thesis demonstrates the clinical relevance of these methods in a study on endometrial carcinoma. A weakly supervised whole slide classifier is trained to predict molecular subtypes, and the developed cell detection and classification tools are used to extract cell-level biomarkers from predicted regions of interest. These biomarkers enable the quantification of subtype-specific cell spatial organization differences, linking computational predictions to interpretable biological features. By integrating transformers, graph-based representations, and self-supervised learning, this thesis introduces scalable and annotation-efficient methodologies for computational pathology. These approaches enhance the efficiency, robustness, and generalization of artificial intelligence models, contributing to the development of clinically relevant tools for cancer diagnosis and characterization.

}, doi = {10.5821/dissertation-2117-439958}, url = {http://hdl.handle.net/10803/695086}, author = {Oscar Pina}, editor = {Ver{\'o}nica Vilaplana} } @conference {cPina25a, title = {Hierarchical Cell-to-Patch Graphs for Context-Aware Cell Classification in Digital Pathology}, booktitle = {21st European Congress on Digital Pathology}, year = {2025}, month = {06/2025}, publisher = {The European Society of Digital and Integrative Pathology}, organization = {The European Society of Digital and Integrative Pathology}, address = {Barcelona}, abstract = {

Cell classification in digital pathology requires spatial context beyond individual cell morphology, particularly for distinguishing tumor vs. normal cells in H\&E-stained images. While traditional segmentation and models like CellNuc-DETR achieve high detection accuracy, their reliance on small image patches limits classification performance by excluding tissue-level context. We propose a hierarchical cell-to-patch graph framework that integrates fine-grained cell features with global spatial information using graph neural networks (GNNs) to enhance classification accuracy while maintaining computational efficiency.

}, url = {https://www.ecdp2025.org/ecdp2025-program.pdf}, author = {Oscar Pina and Lauren Jimenez and Eduard Dorca and Ver{\'o}nica Vilaplana} } @inbook {bCalm25, title = {Identifying brain ageing trajectories using variational autoencoders}, booktitle = {PRedictive Intelligence in MEdicine}, volume = {15155}, number = {Lecture Notes in Computer Sciences}, year = {2025}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, author = {Berta Calm and Irene Cumplido-Mayoral and Juan Domingo Gispert and Ver{\'o}nica Vilaplana} } @article {aPinaa, title = {Layer-Wise Training of Graph Neural Networks With Self-Supervised Learning}, journal = { IEEE Transactions on Neural Networks and Learning Systems,}, year = {2025}, month = {07/2025}, doi = {10.1109/TNNLS.2025.3577702}, author = {Oscar Pina and Ver{\'o}nica Vilaplana} } @conference {cDorca25, title = {Multimodal AI for Atypical Hyperplasia Diagnosis: A Comparative Study of CNNs, GNNs, and Hybrid Models}, booktitle = {21st European Congress on Digital Pathology}, year = {2025}, month = {06/2025}, publisher = {The European Society of Digital and Integrative Pathology}, organization = {The European Society of Digital and Integrative Pathology}, address = {Barcelona}, abstract = {

The diagnosis of atypical hyperplasia in endometrial aspirates is complex due to morphological variations across the menstrual cycle, often leading to interobserver variability. This study explores the use of artificial intelligence to enhance diagnostic accuracy by developing an AI-assisted framework to improve reproducibility and clinical decision-making in gynecological pathology.

}, url = {https://www.ecdp2025.org/ecdp2025-program.pdf}, author = {Eduard Dorca and Oscar Pina and Maria del Rosario Taco and Esther Guerra Fermamdez and Ver{\'o}nica Vilaplana and August Vidal Bel} } @article {aCumplido-Mayorala, title = {Neuroimaging-derived biological brain age and its associations with glial reactivity and synaptic dysfunction cerebrospinal fluid biomarkers}, journal = {Molecular psychiatry}, year = {2025}, month = {04/2025}, abstract = {

Magnetic resonance Imaging (MRI)-derived brain-age prediction is a promising biomarker of biological brain aging. Accelerated brain aging has been found in Alzheimer{\textquoteright}s disease (AD) and other neurodegenerative diseases. However, no previous studies have investigated the relationship between specific pathophysiological pathways in AD and biological brain aging. Here, we studied whether glial reactivity and synaptic dysfunction are associated with biological brain aging in the earliest stages of the Alzheimer{\textquoteright}s\ continuum, and if these mechanisms are differently associated with AD-related cortical atrophy. We further evaluated their effects on cognitive decline. We included 380 cognitively unimpaired individuals from the ALFA+ study, for which we computed their brain-age deltas by subtracting chronological age from their brain age predicted by machine learning algorithms. We studied the cross-sectional linear associations between brain-age delta and cerebrospinal fluid (CSF) biomarkers of synaptic dysfunction (neurogranin, GAP43, synaptotagmin-1, SNAP25, and α-synuclein), glial reactivity (sTREM2, YKL-40, GFAP, and S100b) and inflammation (interleukin-6). We also studied the cross-sectional linear associations between AD signature and these CSF biomarkers, We further evaluated the mechanisms linking baseline brain-age delta and longitudinal cognitive decline by performing mediation analyses. To reproduce our findings on an independent cohort, we included 152 cognitively unimpaired and 310 mild cognitive impaired (MCI) individuals from the ADNI study. We found that higher CSF sTREM2 was associated with a younger brain-age after adjusting for AD pathology, both in ALFA+ cognitively unimpaired and in ADNI MCI individuals. Furthermore, we found that CSF sTREM2 fully mediated the link between older brain-age and cognitive decline in ALFA+. In summary, we showed that the protective microglial state reflected by higher CSF sTREM2 has a beneficial impact on biological brain aging that may partly explains the variability in cognitive decline in early AD stages, independently of AD pathology.

}, issn = {1359-4184}, doi = {https://doi.org/10.1038/s41380-025-02961-x}, url = {https://www.nature.com/articles/s41380-025-02961-x}, author = {Irene Cumplido-Mayoral and Gonzalo S{\'a}nchez-Benavides and Marta Mil{\`a} Alom{\`a} and Carles Falcon and Raffaele Cacciaglia and Carolina Minguillon and Jose L. Molinuevo and Marc Suarez Calvet and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cLems25, title = {Towards a multicentric open DigitAL PatHology assIstant beNchmark: Initial Results from the DALPHIN Study}, booktitle = {United States \& Canadian Academy of Pathology 114th Annual Meeting (USCAP 2025)}, year = {2025}, month = {03/2025}, publisher = {Laboratory Investigation, Volume 105, Issue 3, Supplement, 2025, 103609, ISSN 0023-6837}, organization = {Laboratory Investigation, Volume 105, Issue 3, Supplement, 2025, 103609, ISSN 0023-6837}, address = {Boston, USA}, doi = {https://doi.org/10.1016/j.labinv.2024.103609.}, url = {https://www.sciencedirect.com/science/article/pii/S0023683724032872}, author = {Carlijn M Lems and Nat{\'a}lie Klub{\'\i}{\v c}kov{\'a} and Biagio Brattoli and Taebum Lee and Ver{\'o}nica Vilaplana and Pedro Luis Fern{\'a}ndez and Laura Pons and Milda Poceviciute and Nadieh Khalili and Francesco Ciompi} } @article {aManjabacas25, title = {Twenty years of AFORO: New developments and connections enhancing otolith research}, journal = {Fisheries Research}, volume = {281}, year = {2025}, month = {01/2025}, abstract = {

Since 2003, with the aim of addressing different issues related to otoliths and the advancement of technologies, AFORO acronym of An{\`a}lisi de FORmes d{\textquoteright}Ot{\`o}lits (otolith shape analysis), a computational environment with a set of tools including a website for this purpose, has gradually expanded its functionality. This implies different ways to measure otoliths in order to obtain different types of information of the same individual. The 2D otoliths shape description using different methods permits the comparison between classical methods and the Wavelet transform, used in the automatic classification system of AFORO. The 3D otoliths description in a few images opens the possibility of classifications using volumetric information, which they have performed well. The data of relationships between otolith and fish length in AFORO is used in predator-prey studies. Our website offers the possibility to display otolith georeferencing information interactively. Furthermore, the automatic classification system has been improved by incorporating geographic filters based on georeferenced data. The diverse information that AFORO offers on the otoliths opens the possibility to approach new studies or to improve the existing ones, combining this information or applying the most appropriate one to the specific problem. Classification cases with Wavelets that have been improved by introducing geographical area information will be presented. In addition, Deep Learning algorithms will be introduced by performing classifications with a small subset of otoliths of species which contain a sufficient number of specimens (\>8).

}, keywords = {artificial intelligence, computer Vision, deep learning, neural networks, Otoliths}, issn = {0165-7836}, doi = {https://doi.org/10.1016/j.fishres.2024.107242}, author = {A. Manjabacas and O. Chic and E. Garc{\'\i}a-Ladona and V.M. Tuset and Morros, J.R. and Elisa Sayrol and P. Mart{\'\i}-Puig and J. Forest and J. Vasconcelos and A. Lombarte} } @conference {cPina25b, title = {Unsupervised Domain Adaptation for Cell Detection Across Histopathological Stains}, booktitle = {21st European Congress on Digital Pathology}, year = {2025}, month = {06/2025}, publisher = {The European Society of Digital and Integrative Pathology}, organization = {The European Society of Digital and Integrative Pathology}, address = {Barcelona}, abstract = {

Deep learning models trained on hematoxylin and eosin (H\&E) stained images often fail to generalize to immunohistochemistry (IHC) stains due to domain shifts. The scarcity of annotated IHC datasets limits the applicability of supervised learning. To address this challenge, we propose an unsupervised domain adaptation (UDA) approach that enables CellNuc-DETR to generalize from H\&E to IHC without requiring additional manual annotations.

}, url = {https://www.ecdp2025.org/ecdp2025-program.pdf}, author = {Oscar Pina and Eduard Dorca and Ver{\'o}nica Vilaplana} } @article {aGene-Molad, title = {AmodalAppleSize_RGB-D dataset: RGB-D images of apple trees annotated with modal and amodal segmentation masks for fruit detection, visibility and size estimation}, journal = {Data in Brief}, volume = {52}, year = {2024}, month = {02/2024}, abstract = {

The present dataset comprises a collection of RGB-D apple tree images that can be used to train and test computer vision-based fruit detection and sizing methods. This dataset encompasses two distinct sets of data obtained from a Fuji and an Elstar apple orchards. The Fuji apple orchard sub-set consists of 3925 RGB-D images containing a total of 15335 apples annotated with both modal and amodal apple segmentation masks. Modal masks denote the visible portions of the apples, whereas amodal masks encompass both visible and occluded apple regions. Notably, this dataset is the first public resource to incorporate on-tree fruit amodal masks. This pioneering inclusion addresses a critical gap in existing datasets, enabling the development of robust automatic fruit sizing methods and accurate fruit visibility estimation, particularly in the presence of partial occlusions. Besides the fruit segmentation masks, the dataset also includes the fruit size (calliper) ground truth for each annotated apple. The second sub- set comprises 2731 RGB-D images capturing five Elstar apple trees at four distinct growth stages. This sub-set includes mean diameter information for each tree at every growth stage and serves as a valuable resource for evaluating fruit sizing methods trained with the first sub-set. The present data was employed in the research papers titled "Looking behind occlusions: a study on amodal segmentation for robust on-tree apple fruit size estimation" [1] and {\textquotedblleft}Simultaneous fruit detection and size estimation using multitask deep neural networks{\textquotedblright} [2].

}, keywords = {Agricultural robotics, amodal segmentation, depth image, Fruit measurement, Fruit visibility, Instance Segmentation, modal segmentation, Yield prediction}, doi = {https://doi.org/10.1016/j.dib.2023.110000}, author = {Gen{\'e}-Mola, Jordi and Ferrer-Ferrer, M. and Hemming, J. and Dalfsen, P. and Hoog, D. and Sanz-Cortiella, R. and Rosell-Polo, Joan R. and Morros, J.R. and Ver{\'o}nica Vilaplana and Ruiz-Hidalgo, J. and Gregorio, Eduard} } @article {aHernandez, title = {Bcn20000: Dermoscopic lesions in the wild}, journal = {Nature - Scientific Data}, volume = {11}, year = {2024}, month = {06/2024}, abstract = {

Advancements in dermatological artificial intelligence research require high-quality and comprehensive datasets that mirror real-world clinical scenarios. We introduce a collection of 18,946 dermoscopic images spanning from 2010 to 2016, collated at the Hospital Cl{\'\i}nic in Barcelona, Spain. The BCN20000 dataset aims to address the problem of unconstrained classification of dermoscopic images of skin cancer, including lesions in hard-to-diagnose locations such as those found in nails and mucosa, large lesions which do not fit in the aperture of the dermoscopy device, and hypo-pigmented lesions. Our dataset covers eight key diagnostic categories in dermoscopy, providing a diverse range of lesions for artificial intelligence model training. Furthermore, a ninth out-of-distribution (OOD) class is also present on the test set, comprised of lesions which could not be distinctively classified as any of the others. By providing a comprehensive collection of varied images, BCN20000 helps bridge the gap between the training data for machine learning models and the day-to-day practice of medical practitioners. Additionally, we present a set of baseline classifiers based on state-of-the-art neural networks, which can be extended by other researchers for further experimentation.

}, doi = {https://doi.org/10.1038/s41597-024-03387-w}, author = {Carlos Hernandez and Marc Combalia and Sebastian Podlipnik and Noel CF Codella and Veronica Rotemberg and Allan C Halpern and Ofer Reiter and Cristina Carrera and Alicia Barreiro and Brian Helba and Susana Puig and Ver{\'o}nica Vilaplana and Josep Malvehy} } @phdthesis {dMayoral24, title = {Biological brain-age prediction using Machine Learning on neuroimaging data: Links with pathophysiological mechanisms, dementia risk factors and cognitive decline}, volume = {Doctorate program in Biomedicine}, year = {2024}, month = {06/2024}, type = {PhD Thesis}, abstract = {

Understanding brain aging and its link to Alzheimer{\textquestiondown}s disease (AD) and related disorders (ADRD) is crucial for addressing age-related cognitive decline and neurodegenerative diseases. Age is the primary risk factor for ADRD, with cognitive decline and brain atrophy observed across the lifespan, even in those without dementia. As the population ages, there is a growing need to comprehend normal brain changes and ADRD, and to target fundamental aging mechanisms. Developing accurate biomarkers for biological brain aging is essential for gaining insights into the aging process and its connection to neurodegenerative diseases. Over the last years, neuroimaging-derived brain-age has emerged as a marker for bio- logical brain aging, with literature focusing on assessing its predictive accuracy and its performance by examining its reliability and its ability to evaluate neurodegenerative diseases and brain health. However, there is a lack of validation regarding its association with various neurodegeneration biomarkers and ADRD physiopathological mechanisms, especially in cognitively unimpaired individuals. Therefore, this thesis aimed to validate brain-age across different cohorts and to explore its underlying biological mechanisms, while also examining its association with cognitive decline and modifiable risk factors. To this end, we estimated brain-age by computing machine learning models to predict an individual{\textquestiondown}s chronological age based on neuroimaging data from the UK Biobank cohort. Subsequently, we predicted brain-age on independent cohorts (ALFA+, EPAD, ADNI, and OASIS) and evaluated the associations between brain-age and different biomarkers specific to the pathophysiological mechanisms of AD and related dementias, as well as biomarkers of neurodegeneration, glial activation, and synaptic dysfunction. The findings revealed that brain-age reflects the influence of diverse brain processes and pathologies, as it is associated with neurodegeneration biomarkers, with specific AD and cerebrovascular disease biomarkers, and with biomarkers reflecting activated microglia, as well as with cognitive decline and modifiable risk factors. Taken together, our findings validate neuroimaging brain-age as a biomarker for biological brain aging and highlight its potential as an outcome measure for preventive lifestyle interventions targeting cognitive decline, as well as a tool for understanding potential mechanisms related to aging.

}, url = {http://hdl.handle.net/10803/691460}, author = {Irene Cumplido-Mayoral}, editor = {Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cJimeneza, title = {Breast Cancer Molecular Subtyping from H\&E Whole Slide Images using Foundation Models and Transformers}, booktitle = {Deep Breast Workshop on AI and Imaging for Diagnostic and Treatment Challenges in Breast Care, MICCAI 2024}, year = {2024}, month = {10/2024}, abstract = {

This study tackles the challenge of classifying breast cancer molecular subtypes using H\&E-stained Whole Slide Images (WSI), avoiding the cost and labor limitations of the commonly used immunohistochemistry. We leverage the Attention-Challenging Multiple Instance Learning framework and introduce a variant, ACTrans, which utilizes a transformer aggregator for improved performance. We also compare two publicly available foundation feature extractors pre-trained on large pathology datasets. A comparison of the impact of two different patch sizes at two different magnifications is made. The results obtained in our in-house dataset demonstrate that ACTrans outperforms existing methods, particularly with the UNI model at lower resolutions and larger patch sizes. In this setting, ACTrans achieves an average F1 score of 0.687, a precision of 0.755, a recall of 0.667, and an AUC of 0.812. Furthermore, these approaches enhance interpretability when displaying the attention weights. This method can potentially advance breast cancer diagnostics by leveraging the rich information within H\&E-stained WSIs.

}, author = {Lauren Jimenez and Carlos Hernandez and Ver{\'o}nica Vilaplana} } @conference {cHernandezb, title = {Bridging Domains in Melanoma Diagnostics: Predicting BRAF Mutations and Sentinel Lymph Node Positivity with Attention-Based Models in Histological Images}, booktitle = {IEEE/CVF Conference on Computer Vision and Pattern Recognition (DEF-AI-MIA workshop)}, year = {2024}, month = {06/2024}, abstract = {

Whole Slide Images (WSIs) have significantly advanced the field of pathology by providing highly detailed views of tissue samples. Integrating Deep Learning (DL) into this area of research particularly through transformer-based foundational models has marked a new era in automated image analysis. These foundational models are adept at extracting features from WSIs an essential step in their analysis process. The subsequent application of weakly supervised learning techniques combines these features to predict critical biomarkers such as BRAF mutations and sentinel lymph node (SLN) biopsy positivity which are vital in guiding patient treatment strategies. However the limited availability of labelled datasets in pathology hinders the usefulness of DL models. Domain adaptation strategies adeptly overcome this hurdle enabling model knowledge transfer between different tissue types thus addressing data scarcity. Our study employs a form of domain adaptation by fine-tuning two DINOv2 models one pre-trained on natural images and the other on WSI of colorectal cancer from the TCGA dataset adapting them for melanoma analysis. We also incorporate a comparison with features extracted by a third DINOv1 model trained solely on WSIs of breast cancer. With this approach we find some notable success in detecting BRAF mutations. Nonetheless predicting SLN positivity presents a more intricate challenge largely due to the indirect correlation between local histopathological features in WSIs of primary tumours and lymph node metastasis manifestation.\ 

}, author = {Carlos Hernandez and Lauren Jimenez and Ver{\'o}nica Vilaplana} } @conference {cPinad, title = {Cell-DETR: Efficient cell detection and classification in WSIs with transformers}, booktitle = {Medical Imaging with Deep Learning (MIDL 2024)}, year = {2024}, month = {07/2024}, abstract = {

Understanding cell interactions and subpopulation distribution is crucial for pathologists to support their diagnoses. This cell information is traditionally extracted from segmentation methods, which poses significant computational challenges on processing Whole Slide Images (WSIs) due to their giga-size nature. Nonetheless, the clinically relevant tasks are nuclei detection and classification rather than segmentation. In this manuscript, we undertake a comprehensive exploration of the applicability of detection transformers for cell detection and classification (Cell-DETR). Not only do we demonstrate the effectiveness of the method by achieving state-of-the-art performance on well-established benchmarks, but we also develop a pipeline to tackle these tasks on WSIs at scale to enable the development of downstream applications. We show its efficiency and feasibility by reporting a significantly faster inference time on a dataset featuring large WSIs. By addressing the challenges associated with large-scale cell detection, our work contributes valuable insights that pave the way for improved diagnostics and downstream applications leveraging cell-level information.

}, author = {Oscar Pina and Eduard Dorca and Ver{\'o}nica Vilaplana} } @article {aPerez-Cano24, title = {Combining graph neural networks and computer vision methods for cell nuclei classification in lung tissue}, journal = {Heliyon}, volume = {10}, year = {2024}, month = {03/2024}, issn = {2405-8440}, doi = {https://doi.org/10.1016/j.heliyon.2024.e28463}, author = {Jose Perez-Cano and Irene Sansano Valero and D. Anglada and Oscar Pina and Salembier, P. and Marqu{\'e}s, F.} } @article {aPina, title = {Feature propagation as self-supervision signals on graphs}, journal = {Knowledge-Based Systems}, volume = {289}, year = {2024}, month = {04/2024}, doi = {https://doi.org/10.1016/j.knosys.2024.111512}, author = {Oscar Pina and Ver{\'o}nica Vilaplana} } @conference {cCalm, title = {Identifying brain ageing trajectories using variational autoencoders with regression model in neuroimaging data stratified by sex and validated against dementia-related risk factors}, booktitle = {7th International Workshop on PRedictive Intelligence in MEdicine, MICCAI 2024}, year = {2024}, month = {10/2024}, abstract = {

Neuroimaging-derived brain age has been identified as a pro\-mising biomarker for accelerated brain age; however, the ageing process is highly heterogeneous and there is a need to further study the different brain ageing trajectories. In this study, we implemented a variational autoencoder (VAE) based model coupled with regression to identify different age-related patterns. Additionally, we correlated the patterns obtained, using a linear regression approach, with dementia-related risk factors. The model was evaluated in different cohorts, UK Biobank and ALFA+, to assess the robustness of the approach. The results showed a feasible strategy for detecting and validating brain age-related trajectories to identify possible early deviations using morphological brain data.

}, author = {Berta Calm and Irene Cumplido-Mayoral and Juan Domingo Gispert and Ver{\'o}nica Vilaplana} } @phdthesis {dHernandez24, title = {Implementation of personalized medicine in malignant melanoma patients aided by artificial intelligence}, volume = {PhD}, year = {2024}, month = {11/2024}, type = {PhD Thesis}, abstract = {

Skin cancer, characterized by the uncontrolled growth and spread of abnormal skin cells, remains a significant global health challenge. It predominantly appears on sun-exposed areas like the face, neck, and arms, though it can also develop in less exposed regions. Melanoma, the most aggressive form of skin cancer, is particularly concerning due to its rapid metastasis if not detected early. This aggressive nature underscores the need for timely diagnosis and treatment. While advances have been made in understanding skin cancer mechanisms, the extensive surface area of the skin, as the body{\textquoteright}s largest organ, makes it easy for lesions to go undetected. However, the advent of prospective databases of clinical and imaging data has equipped the medical community with highly sensitive and specific biomarkers for cancer diagnosis. These biomarkers facilitate early detection and accurate diagnosis through non-invasive methods, allowing for effective treatment of melanoma before it spreads. This thesis introduces tools for analyzing melanoma using clinical data and Whole Slide Imaging (WSI). It focuses on identifying early-stage melanoma patients through risk grouping and biomarker detection. By applying advanced survival analysis, pattern recognition techniques, and statistical clustering, we develop predictive and interpretability models aimed at improving early detection and diagnosis. The main outcomes of this thesis are five-fold. Firstly, we evaluate various survival analysis algorithms on cutaneous melanoma datasets, identifying the most effective methods. Our analysis reveals that, to date, treebased methods still surpass deep learning models in performance on survival analysis datasets Secondly, we introduce a Python library, SurvLIMEpy, to enhance model explainability for time-to-event data, demonstrating its validity through experiments with both simulated and large-scale melanoma datasets. Thirdly, our analysis of feature importance in the trained models reveals that the features identified by SurvLIMEpy align closely with clinically relevant features reported in medical literature. Fourthly, we show that machine learning models for patient stratification outperform the AJCC staging system when combined with Quantile-Based Survival Clustering. Finally, we explore the use of AI to predict biomarker status from WSIs, utilizing selfsupervised feature extractors and Multiple Instance Learning. The concluding sections discuss the effectiveness of the methodologies employed, their benefits, and their potential impact on the treatment of skin cancer patients while also outlining future research directions to address this critical medical and scientific challenge.

}, doi = {10.5821/dissertation-2117-417796 }, author = {Carlos Hernandez}, editor = {Ver{\'o}nica Vilaplana} } @inbook {bHernandez, title = {Interpreting Machine Learning Models for Survival Analysis: A Study of Cutaneous Melanoma Using the SEER Database}, booktitle = {Explainable Artificial Intelligence and Process Mining Applications for Healthcare,}, volume = {2020}, number = {Communications in Computer and Information Science}, year = {2024}, publisher = {Springer, Cham}, organization = {Springer, Cham}, abstract = {

In this study, we train and compare three types of machine learning algorithms for Survival Analysis: Random Survival Forest, DeepSurv and DeepHit, using the SEER database to model cutaneous malignant melanoma. Additionally, we employ SurvLIMEpy library, a Python package designed to provide explainability for survival machine learning models, to analyse feature importance. The results demonstrate that machine learning algorithms outperform the Cox Proportional Hazards Model. Our work underscores the importance of explainability methods for interpreting black-box models and provides insights into important features related to melanoma prognosis.

}, isbn = {978-3-031-54302-9}, issn = {978-3-031-54303-6}, doi = {https://doi.org/10.1007/978-3-031-54303-6_6}, author = {Carlos Hernandez and Cristian Pach{\'o}n-Garc{\'\i}a and Pedro Delicado and Ver{\'o}nica Vilaplana} } @conference {ca, title = {Lossless and Lossy Compression for Distributed Acoustic Sensing Using Inter-channel Predictions}, booktitle = {SSA Photonic Seismology 2024}, year = {2024}, month = {10/2024}, address = {Vancouver}, abstract = {

Distributed Acoustic Sensing (DAS) offer unique advantages to extensive monitoring initiatives due to its long-distance, high-density arrays of real-time acoustic sensors. However, high-resolution and long-term applications generate a large amount of data, on the order of hundreds of terabytes per year, presenting challenges for processing and storage. As a result, leveraging innovative data compression techniques is essential for scaling up DAS monitoring. DAS arrays are composed of multiple channels carrying highly correlated and coherent signals. These redundancies allow to exploit inter-channel compression, which use predictions from consecutive channel signals and achieve a higher compression ratio compared to compressing each channel separately.

In this work, we propose a novel coding scheme for DAS data that improves state-of-the-art compression. Encoding follows a pipeline composed of intra-prediction, inter-prediction, transform and entropy coding. For lowly correlated channels, intra-channel prediction is realized by means of Linear Prediction Coding. For inter-channel prediction, we propose three different methods: (1) prediction by warping and scaling the signal from the consecutive channel, (2) a linear predictor is learned over many channels and (3) wavelet transforms are used to disentangle data signals of different frequency, allowing fine-grained prediction. Entropy coding is done by a combination of adaptive arithmetic coding and run-length coding. The implementation is divided into an encoder and a decoder. The encoder uses bitrate optimization for decisions on the prediction methods and parameter values and can be tuned for either speed or high-compression modes. In addition, we explore lossy quantization by adding tunable quantization of the transformed signal, which we observe to achieve significantly higher compression at the expense of quantization noise. The designed algorithms and the provided implementation facilitate the deployment of long-term DAS monitoring.

}, keywords = {Distributed Acoustic Sensing, Signal compression}, url = {https://ssafallmeeting.secure-platform.com/a/gallery/rounds/39/details/12071}, author = {Segu{\'\i}, Aleix and Ugalde, Arantza and Ventosa, Sergi and Morros, J.R.} } @article {aCumplido-Mayoral, title = {The mediating role of neuroimaging-derived biological brain age between risk factors for dementia and cognitive decline in middle/late-aged asymptomatic individuals: a cohort study}, journal = {The Lancet Healthy Longevity}, year = {2024}, month = {04/2024}, abstract = {

Summary Background Neuroimaging-based brain-age delta has been shown to be a mediator linking cardiovascular risk factors to cognitive function. We aimed to assess the mediating role of brain-age delta in the association between modifiable risk factors of dementia and longitudinal cognitive decline in middle-aged and older individuals who are asymptomatic, stratified by Alzheimer{\textquoteright}s disease pathology. We also explored whether the mediation effect is specific to cognitive domain. Methods In this cohort study, we included participants from the ALFA+ cohort aged between 45 years and 65 years who were cognitively unimpaired and who had available structural MRI, cerebrospinal fluid β-amyloid (Aβ)42 and Aβ40 measurements obtained within 1 year of each other, modifiable risk factors assessment, and cognitive evaluation over 3 years. Participants were recruited from the Barcelonaβeta Brain Research Center (Barcelona, Spain). Included individuals underwent a first assessment between Oct 25, 2016, and Jan 28, 2020, and a follow-up cognitive assessment 3{\textperiodcentered}28 (SD 0{\textperiodcentered}27) years later. We computed brain-age delta and composites of different cognitive function domains (preclinical Alzheimer{\textquoteright}s cognitive composite [PACC], attention, executive function, episodic memory, visual processing, and language). We used partial least squares path modelling to explore mediation effects in the associations between modifiable risk factors (including cardiovascular, mental health, mood, metabolic or endocrine history, and alcohol use) and changes in cognitive composites. To assess the role of Alzheimer{\textquoteright}s disease pathology, we computed separate models for Aβ-negative and Aβ-positive individuals. Findings Of the 419 participants enrolled in ALFA+, 302 met our inclusion criteria, of which 108 participants were classified as Aβ-positive and 194 as Aβ-negative. In Aβ-positive individuals, brain-age delta partially mediated (percent mediation proportion 15{\textperiodcentered}73\% [95\% CI 14{\textperiodcentered}22{\textendash}16{\textperiodcentered}66]) the association between modifiable risk factors and decline in overall cognition (across cognitive domains). Brain-age delta fully mediated (mediation proportion 28{\textperiodcentered}03\% [26{\textperiodcentered}25{\textendash}29{\textperiodcentered}21]) the effect of modifiable risk factors on the PACC, wherein increased values for risk factors correlated with an older brain-age delta, and, consequently, an older brain-age delta was linked to greater PACC decline. This effect appears to be primarily driven by memory decline. Mediation was not significant in Aβ-negative individuals (3{\textperiodcentered}52\% [0{\textperiodcentered}072{\textendash}4{\textperiodcentered}17]) on PACC, although path coefficients were not significantly different from those in the Aβ-positive group. Interpretation Our findings suggest that brain-age delta captures the association between modifiable risk factors and longitudinal cognitive decline in middle-aged and older people. In asymptomatic middle-aged and older individuals who are Aβ-positive, the pathology might be the strongest driver of cognitive decline, whereas the effect of risk factors is smaller. Our results highlight the potential of brain-age delta as an objective outcome measure for preventive lifestyle interventions targeting cognitive decline.

}, doi = {10.1016/S2666-7568(24)00025-4}, author = {Irene Cumplido-Mayoral and Anna Brugulat-Serra and Gonzalo S{\'a}nchez-Benavides and Jose Luis Molinuevo and Marc Suarez-Calvet and Ver{\'o}nica Vilaplana and Juan Domingo Gispert} } @article {aPachon-Garcia, title = {SurvLIMEpy: A Python package implementing SurvLIME}, journal = {Expert Systems With Applications}, volume = {237, Part C}, year = {2024}, month = {03/2024}, abstract = {

In this paper we present SurvLIMEpy, an open-source Python package that implements the SurvLIME algorithm. This method allows to compute local feature importance for machine learning algorithms designed for modelling Survival Analysis data. Our\ implementation takes advantage of the parallelisation paradigm as all computations are performed in a matrix-wise fashion which speeds up execution time. Additionally, SurvLIMEpy assists the user with visualization tools to better understand the result of the algorithm. The package supports a wide variety of survival models, from the Cox Proportional Hazards Model to deep learning models such as DeepHit or DeepSurv. Two types of experiments are presented in this paper. First, by means of simulated data, we study the ability of the algorithm to capture the importance of the features. Second, we use three open source survival datasets together with a set of survival algorithms in order to demonstrate how SurvLIMEpy behaves when applied to different models.

}, keywords = {eXplainable Artificial Intelligence, Interpretable Machine Learning, machine learning, python, Survival Analysis}, author = {Cristian Pach{\'o}n-Garc{\'\i}a and Carlos Hernandez and Pedro Delicado and Ver{\'o}nica Vilaplana} } @conference {cGiardina, title = {Synthesis of Prostate MRI Scans: A Comparison of StyleGAN2-ADA and Latent Diffusion Models}, booktitle = {Conferencia de la Asociaci{\'o}n Espa{\~n}ola para la Inteligencia Artificial, IABioMed workshop}, year = {2024}, month = {07/2024}, abstract = {

Prostate cancer is a leading cause of cancer-related death in men globally. Deep learning algorithms hold significant promise for disease classification and detection, but their performance heavily relies on the availability of large training datasets. Generative Adversarial Networks (GANs) and Diffusion Models offer cutting-edge solutions to address this challenge by synthesizing realistic medical data.

This work investigates the potential of StyleGAN2-ADA and Latent Diffusion Models (LDMs) for generating synthetic T2-weighted prostate MRI slices. We leverage a publicly available dataset to train these models and evaluate their ability to create realistic MRI data. Our initial findings demonstrate that both frameworks can produce slices visually similar to real data. However, a crucial distinction lies in their training and inference efficiency.\ 

}, author = {Claudia Giardina and Ver{\'o}nica Vilaplana and M. Pard{\`a}s and Oriol Guardia} } @conference {cPinac, title = {Unsupervised Domain Adaptation for Multi-Stain Cell Detection in Breast Cancer with Transformers}, booktitle = {IEEE/CVF Conference on Computer Vision and Pattern Recognition (DEF-AI-MIA workshop)}, year = {2024}, month = {07/2024}, abstract = {

The complexity in digital pathology image analysis arises from the inherent variability in histopathological slides including tissue specimen differences and stain variations. While publicly available datasets are increasing they primarily focus on hematoxylin and eosin (H\&E) staining yet pathologists often require analysis across multiple stains for comprehensive diagnosis. The poor cross-domain generalization of deep learning models intensifies these challenges making it unfeasible to implement without exhaustive annotations in each stain. This manual curation process is time-consuming and requires the creation of sufficiently large and precise datasets. In this work we address these challenges focusing on breast cancer across four crucial stains: ER PR HER2 and Ki-67. Given the necessity of cell-level information for diagnosis we concentrate on cell detection tasks. Leveraging unsupervised domain adaptation techniques we bridge the gap between publicly available annotated H\&E datasets and unlabeled data in other stains. Utilizing detection transformers we demonstrate the superiority of adversarial feature learning over source-only and image-level generative methods. Our work contributes to improving digital pathology analysis by enabling robust and efficient pipelines across multiple stains. By leveraging unsupervised domain adaptation we facilitate the development of accurate computer-aided diagnosis pipelines capable of handling stain variations and enhancing diagnostic accuracy in practical settings.

}, url = {https://openaccess.thecvf.com/content/CVPR2024W/DEF-AI-MIA/papers/Pina_Unsupervised_Domain_Adaptation_for_Multi-Stain_Cell_Detection_in_Breast_Cancer_CVPRW_2024_paper.pdf}, author = {Oscar Pina and Ver{\'o}nica Vilaplana} } @article {aCumplido-Mayoral22, title = {Biological Brain Age Prediction Using Machine Learning on Structural Neuroimaging Data: Multi-Cohort Validation Against Biomarkers of Alzheimer{\textquoteright}s Disease and Neurodegeneration stratified by sex}, journal = {eLife}, volume = {12}, year = {2023}, month = {04/2023}, abstract = {

Brain-age can be inferred from structural neuroimaging and compared to chronological age (brain-age delta) as a marker of biological brain aging. Accelerated aging has been found in neurodegenerative disorders like Alzheimer9s disease (AD), but its validation against markers of neurodegeneration and AD is lacking. Here, imaging-derived measures from the UK Biobank dataset (N=22,661) were used to predict brain-age in 2,314 cognitively unimpaired (CU) individuals at higher risk of AD and mild cognitive impaired (MCI) patients from four independent cohorts with available biomarker data: ALFA+, ADNI, EPAD and OASIS. Brain-age delta was associated with abnormal amyloid-β, more advanced stages (AT) of AD pathology and APOE-ε4 status. Brain-age delta was positively associated with plasma neurofilament light, a marker of neurodegeneration, and sex differences in the brain effects of this marker were found. These results validate brain-age delta as a non-invasive marker of biological brain aging related to markers of AD and neurodegeneration.

}, issn = {2050-084X}, doi = {https://doi.org/10.7554/eLife.81067}, author = {Irene Cumplido-Mayoral and Marina Garc{\'\i}a-Prat and Gregory Operto and Carles Falcon and Mahnaz Shekari and Raffaele Cacciaglia and Marta Mila-Aloma and Luigi Lorenzini and Carolina Minguillon and Jose Luis Molinuevo and Marc Suarez-Calvet and Ver{\'o}nica Vilaplana and Juan Domingo Gispert} } @conference {cCumplido-Mayoral23a, title = {Brain-age mediates the association between modifiable risk factors and cognitive decline early in the AD continuum}, booktitle = {Alzheimer{\textquoteright}s Association International Conference (AAIC)}, year = {2023}, month = {07/2023}, address = {Amsterdam, Netherlands}, author = {Irene Cumplido-Mayoral and Anna Brugulat-Serrat and Gonzalo S{\'a}nchez-Benavides and Armand Gonz{\'a}lez-Escalante and Federica Anastasi and Marta Mila-Aloma and Carles Falcon and Mahnaz Shekari and Raffaele Cacciaglia and Carolina Minguillon and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cCumplido-Mayoral23, title = {Brain-age prediction and its associations with glial and synaptic CSF markers}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2023}, month = {07/2023}, address = {Amsterdam, Netherlands}, author = {Irene Cumplido-Mayoral and Marta Mila-Aloma and Carles Falcon and Raffaele Cacciaglia and Carolina Minguillon and Karine Fauria and Jose Luis Molinuevo and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cHernandez23, title = {Interpreting Machine Learning models for Survival Analysis: A study of Cutaneous Melanoma using the SEER Database}, booktitle = {XAI-Healthcare 2023 Workshop at 21st International Conference of Artificial Intelligence in Medicine (AIME 2023)}, year = {2023}, month = {06/2023}, address = {Portoroz, Slovenia}, author = {Carlos Hernandez and Cristian Pach{\'o}n-Garc{\'\i}a and Pedro Delicado and Ver{\'o}nica Vilaplana} } @conference {cPinab, title = {Layer-wise self-supervised learning on graphs}, booktitle = {KDD 2023 Workshop on Deep Learning on Graphs: Methods and Applications (DLG-KDD 2023)}, year = {2023}, month = {08/2023}, address = {Long Beach, USA}, abstract = {

End-to-end training of graph neural networks (GNN) on large graphs presents several memory and computational challenges, and limits the application to shallow architectures as depth exponentially increases the memory and space complexities. In this manuscript, we propose Layer-wise Regularized Graph Infomax, an algorithm to train GNNs layer by layer in a self-supervised manner. We decouple the feature propagation and feature transformation carried out by GNNs to learn node representations in order to derive a loss function based on the prediction of future inputs. We evaluate the algorithm in inductive large graphs and show similar performance to other end to end methods and a substantially increased efficiency, which enables the training of more sophisticated models in one single device. We also show that our algorithm avoids the oversmoothing of the representations, another common challenge of deep GNNs.

}, author = {Oscar Pina and Ver{\'o}nica Vilaplana} } @article {aGene-Mola23, title = {Looking behind occlusions: A study on amodal segmentation for robust on-tree apple fruit size estimation}, journal = {Computers and Electronics in Agriculture}, volume = {209}, year = {2023}, month = {04/2023}, abstract = {

The detection and sizing of fruits with computer vision methods is of interest because it provides relevant information to improve the management of orchard farming. However, the presence of partially occluded fruits limits the performance of existing methods, making reliable fruit sizing a challenging task. While previous fruit segmentation works limit segmentation to the visible region of fruits (known as modal segmentation), in this work we propose an amodal segmentation algorithm to predict the complete shape, which includes its visible and occluded regions. To do so, an end-to-end convolutional neural network (CNN) for simultaneous modal and amodal instance segmentation was implemented. The predicted amodal masks were used to estimate the fruit diameters in pixels. Modal masks were used to identify the visible region and measure the distance between the apples and the camera using the depth image. Finally, the fruit diameters in millimetres (mm) were computed by applying the pinhole camera model. The method was developed with a Fuji apple dataset consisting of 3925 RGB-D images acquired at different growth stages with a total of 15,335 annotated apples, and was subsequently tested in a case study to measure the diameter of Elstar apples at different growth stages. Fruit detection results showed an F1-score of 0.86 and the fruit diameter results reported a mean absolute error (MAE) of 4.5\ mm and R2\ =\ 0.80 irrespective of fruit visibility. Besides the diameter estimation, modal and amodal masks were used to automatically determine the percentage of visibility of measured apples. This feature was used as a confidence value, improving the diameter estimation to MAE\ =\ 2.93\ mm and R2\ =\ 0.91 when limiting the size estimation to fruits detected with a visibility higher than 60\%. The main advantages of the present methodology are its robustness for measuring partially occluded fruits and the capability to determine the visibility percentage. The main limitation is that depth images were generated by means of photogrammetry methods, which limits the efficiency of data acquisition. To overcome this limitation, future works should consider the use of commercial RGB-D sensors. The code and the dataset used to evaluate the method have been made publicly available at\ https://github.com/GRAP-UdL-AT/Amodal_Fruit_Sizing.

}, keywords = {deep learning, Fruit detection, Fruit measurement, Fruit visibility, Precision agriculture, Yield estimation}, issn = {ISSN 0168-1699}, doi = {https://doi.org/10.1016/j.compag.2023.107854}, url = {https://authors.elsevier.com/sd/article/S0168-1699(23)00242-9}, author = {Gen{\'e}-Mola, Jordi and Ferrer-Ferrer, M. and Gregorio, Eduard and Blok, P. M. and Hemming, J. and Morros, J.R. and Rosell-Polo, Joan R. and Ver{\'o}nica Vilaplana and Ruiz-Hidalgo, J.} } @article {aFerrer-Ferrer, title = {Simultaneous Fruit Detection and Size Estimation Using Multitask Deep Neural Networks }, journal = {Biosystems Engineering}, volume = {233}, year = {2023}, month = {09/2023}, pages = {63-75}, abstract = {

The measurement of fruit size is of great interest to estimate the yield and predict the harvest resources in advance. This work proposes a novel technique for in-field apple detection and measurement based on Deep Neural Networks. The proposed\ \ framework was trained with RGB-D data and consists of an end-to-end multitask Deep Neural Network architecture 13 specifically designed to perform the following tasks: 1) detection and segmentation of each fruit from its surroundings; 2) estimation of the diameter of each detected fruit. The methodology was tested with a total of 15335 annotated apples at different growth stages, with diameters varying from 27 mm to 95 mm. Fruit detection results reported an F1-score for apple detection of 0.88 and a mean absolute error of diameter estimation of 5.64 mm. These are state-of-the-art results with the additional advantages of: a) using an end-to-end multitask trainable network; b) an efficient and fast inference speed; and c) being based on RGB-D data which can be acquired with affordable depth cameras. On the contrary, the main disadvantage is the need of annotating a large amount of data with fruit masks and diameter ground truth to train the model. Finally, a fruit visibility analysis showed an improvement in the prediction when limiting the measurement to apples above 65\% of visibility (mean absolute error of 5.09 mm). This suggests that future works should develop a method for automatically identifying the most visible apples and discard the prediction of highly occluded fruits.

}, keywords = {deep learning, Fruit measurement, Fruit visibility, Precision agriculture, Yield estimation}, doi = {https://doi.org/10.1016/j.biosystemseng.2023.07.010}, author = {Ferrer-Ferrer, M. and Ruiz-Hidalgo, J. and Gregorio, Eduard and Ver{\'o}nica Vilaplana and Morros, J.R. and Gen{\'e}-Mola, Jordi} } @conference {cCombaliae, title = {Artificial intelligence to predict positivity of sentinel lymph node biopsy in melanoma patients}, booktitle = {European Association of Dermato Oncology (EADO 2022)}, year = {2022}, month = {04/2022}, author = {Marc Combalia and Sebastian Podlipnik and Carlos Hernandez and Sergio Garc{\'\i}a and Joan Ficapal and Julio Burgos and Ver{\'o}nica Vilaplana and Josep Malvehy} } @conference {cCumplido-Mayoral22, title = {Biological brain age prediction using machine learning on structural neuroimaging data: Multi-cohort validation against biomarkers of Alzheimer{\textquoteright}s disease and neurodegeneration stratified by sex}, booktitle = {15th Clinical Trials on Alzheimer{\textquoteright}s Disease Conference (CTAD)}, year = {2022}, month = {11/2022}, address = {San Francisco, USA}, author = {Irene Cumplido-Mayoral and Marta Mila-Aloma and Luigi Lorenzini and Alle Meije Wink and H. Mutsaerts and Sven Haller and Ga{\"e}l Chetelat and Frederik Barkhof and Marc Suarez-Calvet and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cCumplido-Mayoral, title = {Biological Brain Age Prediction Using Machine Learning on Structural Neuroimaging Data: Multi-Cohort Validation Against Biomarkers of Alzheimer{\textquoteright}s Disease and Neurodegeneration}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2022}, month = {07/2022}, author = {Irene Cumplido-Mayoral and Marina Garc{\'\i}a-Prat and Greg Operto and Carles Falcon and Mahnaz Shekari and Raffaele Cacciaglia and Marta Mila-Aloma and Marc Suarez Calvet and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cHernandez22a, title = {Contrastive and attention-based multiple instance learning for the prediction of sentinel lymph node status from histopathologies of primary melanoma tumours.}, booktitle = {Cancer Prevention through early detecTion (Caption) Workshop at 25th International Conference on Medical Image Computing and Computer Assisted Intervention (MICCAI 2022)}, year = {2022}, month = {09/2022}, abstract = {

Sentinel lymph node status is a crucial prognosis factor for melanomas; nonetheless, the invasive surgery required to obtain it always puts the patient at risk. In this study, we develop a Deep Learning-based approach to predict lymph node metastasis from Whole Slide Images of primary tumours. Albeit very informative, these images come with complexities that hamper their use in machine learning applications, namely their large size and limited datasets. We propose a pre-training strategy based on self-supervised contrastive learning to extract better image feature representations and an attention-based Multiple Instance Learning approach to enhance the model{\textquoteright}s performance. With this work, we quantitatively demonstrate that combining both methods improves various classification metrics and qualitatively show that contrastive learning encourages the network to output higher attention scores to tumour tissue and lower scores to image artifacts.

}, author = {Carlos Hernandez and Marc Combalia and Susana Puig and Josep Malvehy and Ver{\'o}nica Vilaplana} } @article {aTemprana-Salvador22, title = {DigiPatICS: Digital Pathology Transformation of the Catalan Health Institute Network of 8 Hospitals - Planification, Implementation and Preliminary Results}, journal = {Diagnostics}, volume = {12}, year = {2022}, month = {03/2022}, chapter = {852}, abstract = {

Complete digital pathology transformation for primary histopathological diagnosis is a challenging yet rewarding endeavor. Its advantages are clear with more efficient workflows, but there are many technical and functional difficulties to be faced. The Catalan Health Institute (ICS) has started its DigiPatICS project, aiming to deploy digital pathology in an integrative, holistic, and comprehensive way within a network of 8 hospitals, over 168 pathologists, and over 1 million slides each year. We describe the bidding process and the careful planning that was required, followed by swift implementation in stages. The purpose of the DigiPatICS project is to increase patient safety and quality of care, improving diagnosis and the efficiency of processes in the pathological anatomy departments of the ICS through process improvement, digital pathology, and artificial intelligence tools.

}, keywords = {artificial intelligence, computational pathology, deep learning, digital pathology, implementation, LIS, primary diagnosis, telepathology, workflow}, doi = {10.3390/diagnostics12040852}, url = {https://www.mdpi.com/2075-4418/12/4/852}, author = {Jordi Temprana-Salvador and Pau L{\'o}pez-Garc{\'\i}a and Josep Castellv{\'\i} Vives and Llu{\'\i}s de Haro and Eudald Ballesta and Matias Rojas Abusleme and Miquel Arrufat and Ferran Marques and Casas, J. and Carlos Gallego and Laura Pons and Jos{\'e} Luis Mate and Pedro Luis Fern{\'a}ndez and Eugeni L{\'o}pez-Bonet and Ramon Bosch and Salom{\'e} Mart{\'\i}nez and Santiago Ram{\'o}n y Cajal and Xavier Matias-Guiu} } @article {aa, title = {QU-BraTS: MICCAI BraTS 2020 Challenge on Quantifying Uncertainty in Brain Tumor Segmentation--Analysis of Ranking Metrics and Benchmarking Results}, journal = {Journal of Machine Learning for Biomedical Imaging}, year = {2022}, month = {08/2022}, abstract = {

Deep learning (DL) models have provided state-of-the-art performance in various medical imaging benchmarking challenges, including the Brain Tumor Segmentation (BraTS) challenges. However, the task of focal pathology multi-compartment segmentation (e.g., tumor and lesion sub-regions) is particularly challenging, and potential errors hinder translating DL models into clinical workflows. Quantifying the reliability of DL model predictions in the form of uncertainties could enable clinical review of the most uncertain regions, thereby building trust and paving the way toward clinical translation. Several uncertainty estimation methods have recently been introduced for DL medical image segmentation tasks. Developing scores to evaluate and compare the performance of uncertainty measures will assist the end-user in making more informed decisions. In this study, we explore and evaluate a score developed during the BraTS 2019 and BraTS 2020 task on uncertainty quantification (QU-BraTS) and designed to assess and rank uncertainty estimates for brain tumor multi-compartment segmentation. This score (1) rewards uncertainty estimates that produce high confidence in correct assertions and those that assign low confidence levels at incorrect assertions, and (2) penalizes uncertainty measures that lead to a higher percentage of under-confident correct assertions. We further benchmark the segmentation uncertainties generated by 14 independent participating teams of QU-BraTS 2020, all of which also participated in the main BraTS segmentation task. Overall, our findings confirm the importance and complementary value that uncertainty estimates provide to segmentation algorithms, highlighting the need for uncertainty quantification in medical image analyses. Finally, in favor of transparency and reproducibility, our evaluation code is made publicly available at:\ this https URL.

}, url = {https://www.melba-journal.org/papers/2022:026.html}, author = {Raghav Metha and Angelos Filos and Ujjwal Baid and Laura Mora and Ver{\'o}nica Vilaplana and Christos Davatzikos and Bjoern Menze and Spyridon Bakas and Yarin Gal and Tar Arbel} } @article {cBellver-Bueno20, title = {RefVOS: A Closer Look at Referring Expressions for Video Object Segmentation}, journal = {Multimedia Tools and Applications}, year = {2022}, month = {07/2022}, abstract = {

The task of video object segmentation with referring expressions (language-guided VOS) is to, given a linguistic phrase and a video, generate binary masks for the object to which the phrase refers. Our work argues that existing benchmarks used for this task are mainly composed of trivial cases, in which referents can be identified with simple phrases. Our analysis relies on a new categorization of the phrases in the DAVIS-2017 and Actor-Action datasets into trivial and non-trivial REs, with the non-trivial REs annotated with seven RE semantic categories. We leverage this data to analyze the results of RefVOS, a novel neural network that obtains competitive results for the task of language-guided image segmentation and state of the art results for language-guided VOS. Our study indicates that the major challenges for the task are related to understanding motion and static actions.

}, doi = {https://doi.org/10.1007/s11042-022-13413-x}, author = {Bellver-Bueno, M{\'\i}riam and Ventura, C. and Silberer, Carina and Kazakos, Ioannis and Jordi Torres and Xavier Gir{\'o}-i-Nieto} } @article {aSalgueirob, title = {SEG-ESRGAN: A multi-task network for super-resolution and semantic segmentation of remote sensing images}, journal = {Remote Sensing}, volume = {14}, year = {2022}, month = {2022}, chapter = {5862}, abstract = {

The production of highly accurate land cover maps is one of the primary challenges in remote sensing, which depends on the spatial resolution of the input images. Sometimes, high-resolution imagery is not available or is too expensive to cover large areas or to perform multitemporal analysis. In this context, we propose a multi-task network to take advantage of the freely available Sentinel-2 imagery to produce a super-resolution image, with a scaling factor of 5, and the corresponding high-resolution land cover map. Our proposal, named SEG-ESRGAN, consists of two branches: the super-resolution branch, that produces Sentinel-2 multispectral images at 2 m resolution, and an encoder{\textendash}decoder architecture for the semantic segmentation branch, that generates the enhanced land cover map. From the super-resolution branch, several skip connections are retrieved and concatenated with features from the different stages of the encoder part of the segmentation branch, promoting the flow of meaningful information to boost the accuracy in the segmentation task. Our model is trained with a multi-loss approach using a novel dataset to train and test the super-resolution stage, which is developed from Sentinel-2 and WorldView-2 image pairs. In addition, we generated a dataset with ground-truth labels for the segmentation task. To assess the super-resolution improvement, the PSNR, SSIM, ERGAS, and SAM metrics were considered, while to measure the classification performance, we used the IoU, confusion matrix and the F1-score. Experimental results demonstrate that the SEG-ESRGAN model outperforms different full segmentation and dual network models (U-Net, DeepLabV3+, HRNet and Dual_DeepLab), allowing the generation of high-resolution land cover maps in challenging scenarios using Sentinel-2 10 m bands.

}, issn = {2072-4292 }, doi = {https://doi.org/10.3390/rs142}, url = {https://doi.org/10.3390/rs14225862 }, author = {Luis Salgueiro and Javier Marcello and Ver{\'o}nica Vilaplana} } @conference {cPinaa, title = {Self-supervised graph representations of WSIs}, booktitle = {Geometric Deep Learning in Medical Image Analysis}, year = {2022}, month = {2022}, abstract = {

In this manuscript we propose a framework for the analysis of whole slide images (WSI) on the cell entity space with self-supervised deep learning on graphs and explore its representation quality at different levels of application. It consists of a two step process in which the cell level analysis is performed locally, by clusters of nearby cells that can be seen as small regions of the image, in order to learn representations that capture the cell environment and distribution. In a second stage, a WSI graph is generated with these regions as nodes and the representations learned as initial node embeddings. The graph is leveraged for a downstream task, region of interest (ROI) detection addressed as a graph clustering. The representations outperform the evaluation baselines at both levels of application, which has been carried out predicting whether a cell, or region, is tumor or not based on its learned representations with a logistic regressor.

}, url = {https://proceedings.mlr.press/v194/pina22a/pina22a.pdf}, author = {Oscar Pina and Ver{\'o}nica Vilaplana} } @conference {cHernandeza, title = {Sentinel lymph node status prediction using self-attention networks and contrastive learning from routine histology images of primary tumours}, booktitle = {Medical Imaging with Deep Learning MIDL 2022}, year = {2022}, month = {07/2022}, abstract = {

Deep learning-based computational pathology approaches are becoming increasingly prominent in histopathology image analysis. However, these images typically come with drawbacks that hamper automatic analysis, which include: labeled sample scarcity or the extremely large size of the images (ranging from\ \ to\ \ pixels). Nonetheless, they have proven to be a powerful tool for diagnosis and risk prevention. One such prevention is reducing the number of patients who undergo surgeries that do not benefit them. This study develops a pipeline for predicting sentinel lymph node (SLN) metastasis non-invasively from digitised Whole Slide Images (WSI) of primary melanoma tumours. Furthermore, we combine the use of a weakly supervised architecture with self-supervised contrastive pre-training. We experimentally demonstrate that 1) the use of self-attention improves sentinel lymph node status prediction and 2) self-supervised contrastive learning improves the quality of the learned representations compared to a standard ImageNet pre-training, which boosts the model{\textquoteright}s performance.

}, author = {Carlos Hernandez and Marc Combalia and Josep Malvehy and Ver{\'o}nica Vilaplana} } @conference {cHernandez22, title = {Sentinel lymph node status prediction with self-attention neural networks using histologies of primary melanoma tumours}, booktitle = {European Association of Dermato Oncology (EADO 2022)}, year = {2022}, month = {04/2022}, author = {Carlos Hernandez and Ver{\'o}nica Vilaplana and Marc Combalia and Sergio Garc{\'\i}a and Sebastian Podlipnik and Julio Burgos and Susana Puig and Josep Malvehy} } @conference {cDuartec, title = {Sign Language Video Retrieval with Free-Form Textual Queries}, booktitle = {CVPR 2022 - CVF/IEEE Conference on Computer Vision and Pattern Recognition}, year = {2022}, abstract = {

Systems that can efficiently search collections of sign language videos have been highlighted as a useful application of sign language technology. However, the problem of searching videos beyond individual keywords has received limited attention in the literature. To address this gap, in this work we introduce the task of sign language retrieval with free-form textual queries: given a written query (e.g., a sentence) and a large collection of sign language videos, the objective is to find the signing video in the collection that best matches the written query. We propose to tackle this task by learning cross-modal embeddings on the recently introduced large-scale How2Sign dataset of American Sign Language (ASL). We identify that a key bottleneck in the performance of the system is the quality of the sign video embedding which suffers from a scarcity of labeled training data. We, therefore, propose SPOT-ALIGN, a framework for interleaving iterative rounds of sign spotting and feature alignment to expand the scope and scale of available training data. We validate the effectiveness of SPOT-ALIGN for learning a robust sign video embedding through improvements in both sign recognition and the proposed video retrieval task.

}, author = {Amanda Duarte and Samuel Albanie and Xavier Gir{\'o}-i-Nieto and G{\"u}l Varol} } @conference {cPina, title = {Structural Networks for Brain Age Prediction}, booktitle = {Medical Imaging with Deep Learning (MIDL 2022)}, year = {2022}, month = {08/2022}, abstract = {

Biological networks have gained considerable attention within the Deep Learning community because of the promising framework of Graph Neural Networks (GNN), neural models that operate in complex networks. In the context of neuroimaging, GNNs have successfully been employed for functional MRI processing but their application to ROI-level structural MRI (sMRI) remains mostly unexplored. In this work we analyze the implementation of these geometric models with sMRI by building graphs of ROIs (ROI graphs) using tools from Graph Signal Processing literature and evaluate their performance in a downstream supervised task, age prediction. We first make a qualitative and quantitative comparison of the resulting networks obtained with common graph topology learning strategies. In a second stage, we train GNN-based models for brain age prediction. Since the order of every ROI graph is exactly the same and each vertex is an entity by itself (a ROI), we evaluate whether including ROI information during message-passing or global pooling operations is beneficial and compare the performance of GNNs against a Fully-Connected Neural Network baseline. The results show that ROI-level information is needed during the global pooling operation in order to achieve competitive results. However, no relevant improvement has been detected when it is incorporated during the message passing. These models achieve a MAE of 4.27 in hold-out test data, which is a performance very similar to the baseline, suggesting that the inductive bias included with the obtained graph connectivity is relevant and useful to reduce the dimensionality of the problem

}, author = {Oscar Pina and Irene Cumplido-Mayoral and Raffaele Cacciaglia and Jos{\'e} Mar{\'\i}a Gonz{\'a}lez-de-Ech{\'a}varri and Juan D. Gispert and Ver{\'o}nica Vilaplana} } @phdthesis {dSalgueiro22, title = {Super-resolution and semantic segmentation of remote sensing images using deep learning techniques}, volume = {PhD}, year = {2022}, month = {10/2022}, abstract = {

Remote sensing for Earth observation is a growing scientific field essential for many human activities. Among the different applications in the Remote Sensing domain, the production of thematic maps, such as Land Cover and Land Use, are among the most relevant, as this information plays a critical role in management, planning and monitoring activities at different levels. In this context, the Sentinel-2 satellites are of great importance since they provide open data on land and coastal areas at different spatial resolutions (10, 20, and 60 m), democratizing usability, and creating a high potential for the generation of valuable information, useful in many scenarios, such as agriculture, forestry, land cover and urban planning, among others.

In this thesis, we aim to exploit the usability of Sentinel-2 data by applying deep learning techniques, which are revolutionizing the world of computer vision and, recently, remote sensing. First, we propose super-resolution models to improve the spatial details of the different Sentinel-2 bands, and second, we propose the conjunction of semantic segmentation with super-resolution to generate improved land cover maps that benefit from the enhanced spatial details of the bands.

We first address super-resolution by proposing two different models, one for the 10 m/pixel bands to reach 2 m/pixel and another for the 20 and 60 m/pixel bands to achieve 10 m/pixel. Then, we propose two different multitasking models to derive land cover maps. The first one extending a semantic segmentation model to produce an additional super-resolution image and the second, improving our first super-resolution approach, to provide a semantic segmentation map, as well. We combine features of the different tasks within a single model to improve performance and to generate a high-resolution image with the corresponding highquality land cover map. All models developed were evaluated, quantitatively and qualitatively, using different datasets, showing excellent performance in diverse complex scenarios.

}, author = {Luis Salgueiro}, editor = {Ver{\'o}nica Vilaplana and Javier Marcello} } @conference {cMayoral21a, title = {Brain structural alterations in cognitively unimpaired individuals with discordant amyloid-β PET and CSF Aβ42 status: findings using Machine Learning}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2021}, month = {07/2021}, author = {Irene Cumplido-Mayoral and Mahnaz Shekari and Gemma Salvad{\'o} and Greg Operto and Raffaele Cacciaglia and Carles Falcon and Aida Ni{\~n}erola Baiz{\'a}n and Andr{\'e}s Perissinotti and Carolina Minguillon and Karine Fauria and Ivonne Suridjan and Gwendlyn Kollmorgen and Jose Luis Molinuevo and Henrik Zetterberg and Kaj Blennow and Marc Suarez Calvet and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @article {aAbadal, title = {A Dual Network for Super-Resolution and Semantic Segmentation of Sentinel-2 imagery}, journal = {Remote Sensing}, volume = {13}, year = {2021}, month = {2021}, pages = {4547}, abstract = {

There is a growing interest in the development of automated data processing workflows that provide reliable, high spatial resolution land cover maps. However, high-resolution remote sensing images are not always affordable. Taking into account the free availability of Sentinel-2 satellite data, in this work we propose a deep learning model to generate high-resolution segmentation maps from low-resolution inputs in a multi-task approach. Our proposal is a dual-network model with two branches: the Single Image Super-Resolution branch, that reconstructs a high-resolution version of the input image, and the Semantic Segmentation Super-Resolution branch, that predicts a high-resolution segmentation map with a scaling factor of 2. We performed several experiments to find the best architecture, training and testing on a subset of the S2GLC 2017 dataset. We based our model on the DeepLabV3+ architecture, enhancing the model and achieving an improvement of 5\% on IoU and almost 10\% on the recall score. Furthermore, our qualitative results demonstrate the effectiveness and usefulness of the proposed approach.

}, author = {Sa{\"u}c Abadal and Luis Salgueiro and Javier Marcello and Ver{\'o}nica Vilaplana} } @conference {cDuarte20, title = {How2Sign: A Large-scale Multimodal Dataset for Continuous American Sign Language}, booktitle = {CVPR 2021}, year = {2021}, month = {06/2021}, abstract = {

Sign Language is the primary means of communication for the majority of the Deaf community. One of the factors that has hindered the progress in the areas of automatic sign language recognition, generation, and translation is the absence of large annotated datasets, especially continuous sign language datasets, i.e. datasets that are annotated and segmented at the sentence or utterance level. Towards this end, in this work we introduce How2Sign, a work-in-progress dataset collection. How2Sign consists of a parallel corpus of 80 hours of sign language videos (collected with multi-view RGB and depth sensor data) with corresponding speech transcriptions and gloss annotations. In addition, a three-hour subset was further recorded in a geodesic dome setup using hundreds of cameras and sensors, which enables detailed 3D reconstruction and pose estimation and paves the way for vision systems to understand the 3D geometry of sign language.





}, author = {Amanda Duarte and S. Palaskar and Lucas Ventura and Ghadiyaram, Deepti and DeHaan, Kenneth and F. Metze and Jordi Torres and Xavier Gir{\'o}-i-Nieto} } @conference {cHernandez, title = {Implementation of personalized medicine in cutaneous melanoma patients aided by artificial intelligence}, booktitle = {10th World Congress of2 Melanoma / 17th EADO Congress}, year = {2021}, month = {04/2021}, author = {Carlos Hernandez and Anil Kiroglu and Sergio Garc{\'\i}a and Joan Ficapal and Julio Burgos and Sebastian Podlipnik and Neus Calbet and Susana Puig and Josep Malvehy and Ver{\'o}nica Vilaplana and Marc Combalia} } @conference {cMayoral21, title = {Machine learning on combined neuroimaging and plasma biomarkers for triaging participants of secondary prevention trials in Alzheimer{\textquoteright}s Disease}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2021}, month = {07/2021}, author = {Irene Cumplido-Mayoral and Gemma Salvad{\'o} and Mahnaz Shekari and Carles Falcon and Marta Mil{\`a} Alom{\`a} and Aida Ni{\~n}erola Baiz{\'a}n and Jose Luis Molinuevo and Henrik Zetterberg and Kaj Blennow and Marc Suarez Calvet and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @inbook {bMora, title = {MRI brain tumor segmentation and uncertainty estimation using 3D-UNet architectures}, booktitle = {Brainlesion: Glioma, Multiple Sclerosis, Stroke and Traumatic Brain Injuries. BrainLes 2020}, volume = {12658}, number = {Lecture Notes in Computer Science}, year = {2021}, pages = {376-390}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Automation of brain tumor segmentation in 3D magnetic resonance images (MRIs) is key to assess the diagnostic and treatment of the disease. In recent years, convolutional neural networks (CNNs) have shown improved results in the task. However, high memory consumption is still a problem in 3D-CNNs. Moreover, most methods do not include uncertainty information, which is especially critical in medical diagnosis. This work studies 3D encoder-decoder architectures trained with patch-based techniques to reduce memory consumption and decrease the effect of unbalanced data. The different trained models are then used to create an ensemble that leverages the properties of each model, thus increasing the performance. We also introduce voxel-wise uncertainty information, both epistemic and aleatoric using test-time dropout (TTD) and data-augmentation (TTA) respectively. In addition, a hybrid approach is proposed that helps increase the accuracy of the segmentation. The model and uncertainty estimation measurements proposed in this work have been used in the BraTS{\textquoteright}20 Challenge for task 1 and 3 regarding tumor segmentation and uncertainty estimation.

}, isbn = {978-3-030-72083-4}, issn = {978-3-030-72084-1}, doi = {https://doi.org/10.1007/978-3-030-72084-1_34}, author = {Laura Mora and Ver{\'o}nica Vilaplana} } @article {xGiro-i-Nieto21a, title = {Object Detection with Deep Learning}, year = {2021}, abstract = {

Object detection in computer vision is the task of localizing and categorizing object instances in still images. This talk reviews the main approaches for solving the task with deep neural networks, following a historically perspective starting from the image classification task.


[GSlides]

}, author = {Xavier Gir{\'o}-i-Nieto and Ventura, C.} } @article {xEscobar21, title = {Object Model Adaptation for Multiple Object Tracking}, year = {2021}, abstract = {

Multiple object tracking is a broadly used task in multi- ple applications, all the way from bioengineering to security applications. In this paper we propose a variation of RVOS by adding the center estimation of detected instances, by means of a second head in the decoder which is assigned the task of detecting the corresponding object{\textquoteright}s bounding box arithmetic center. We have trained the model using three variants of the cross-entropy loss, which has been adapted to tackle the class imbalance caused by the fact that the center of an object is represented by only one pixel of the image, and have obtained some promising results.

}, author = {Escobar, Miquel}, editor = {Girbau, A. and Ventura, C. and Xavier Gir{\'o}-i-Nieto and Marqu{\'e}s, F.} } @conference {cPodlipnik21, title = {Personalized medicine in melanoma patients aided by artificial intelligence}, booktitle = {Clinical Translation of Medical Image Computing and Computer Assisted Interventions (CLINICCAI) Workshop at MICCAI}, year = {2021}, month = {09/2021}, abstract = {

The 8th Edition of the American Joint Committee on Cancer (AJCC) staging system1 is the current standard for classifying patients into prognostic and treatment groups. This classification is used to predict the evolution of the patient, and therefore treatment actions provided to the individual. However, patients at the same stage behave differently, indicating that the current classification system is often insufficient to provide a customized prognosis for each patient2. It is, therefore, necessary to improve patient classification into prognostic groups. Furthermore, patients{\textquoteright} systemic and surgical treatments often involve significant toxicities and morbidities that impact their quality of life (i.e., sentinel node biopsy is not needed for 80\% of the melanoma patients, 50\% of patients do not benefit from adjuvant treatment)3. Therefore, melanoma patients should benefit from a more precise risk estimation.

We create a survival dataset for melanoma risk estimation and train survival XGBoost algorithms4 to predict the mortality, relapse, and metastasis risk. We compare their performance to the AJCC 2018 risk stratification system. Furthermore, we train classifiers to predict the risk of a positive lymph node biopsy and distant metastasis on melanoma patients and compare the performance of the proposed system to the clinical practice.

}, author = {Sebastian Podlipnik and Carlos Hernandez and Anil Kiroglu and Sergio Garc{\'\i}a and Joan Ficapal and Julio Burgos and Neus Calbet and Susana Puig and Josep Malvehy and Ver{\'o}nica Vilaplana and Marc Combalia} } @conference {cMayoral21b, title = {Prediction of amyloid pathology in cognitively unimpaired individuals using structural MRI}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2021}, month = {07/2021}, author = {Irene Cumplido-Mayoral and Silvia Ingala and Luigi Lorenzini and Alle Meije Wink and Sven Haller and Jose Luis Molinuevo and Robin Wolz and Alessandro Palombit and Adam J Schwarz and Ga{\"e}l Chetelat and Pierre Payoux and Pablo Martinez-Lage and Giovanni Frisoni and Nick C Fox and Craig W Ritchie and Joanna M Wardlaw and Adam Waldman and Frederik Barkhof and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cManas, title = {Seasonal Contrast: Unsupervised Pre-Training from Uncurated Remote Sensing Data}, booktitle = {International Conference in Computer Vision (ICCV)}, year = {2021}, publisher = {IEEE/CVF}, organization = {IEEE/CVF}, address = {Virtual}, abstract = {

Remote sensing and automatic earth monitoring are key to solve global-scale challenges such as disaster prevention, land use monitoring, or tackling climate change. Although there exist vast amounts of remote sensing data, most of it remains unlabeled and thus inaccessible for supervised learning algorithms. Transfer learning approaches can reduce the data requirements of deep learning algorithms. However, most of these methods are pre-trained on ImageNet and their generalization to remote sensing imagery is not guaranteed due to the domain gap. In this work, we propose Seasonal Contrast (SeCo), an effective pipeline to leverage unlabeled data for in-domain pre-training of re-mote sensing representations. The SeCo pipeline is com-posed of two parts. First, a principled procedure to gather large-scale, unlabeled and uncurated remote sensing datasets containing images from multiple Earth locations at different timestamps. Second, a self-supervised algorithm that takes advantage of time and position invariance to learn transferable representations for re-mote sensing applications. We empirically show that models trained with SeCo achieve better performance than their ImageNet pre-trained counterparts and state-of-the-art self-supervised learning methods on multiple downstream tasks. The datasets and models in SeCo will be made public to facilitate transfer learning and enable rapid progress in re-mote sensing applications.

}, url = {https://arxiv.org/abs/2103.16607}, author = {Ma{\~n}as,Oscar and Lacoste, Alexandre and Xavier Gir{\'o}-i-Nieto and Vazquez, David and Rodr{\'\i}guez, Pau} } @article {aSalgueiroa, title = {Single-image super-resolution of Sentinel-2 low resolution bands with residual dense convolutional neural networks}, journal = {Remote Sensing}, volume = {13}, year = {2021}, month = {2021}, pages = {5007}, abstract = {

Sentinel-2 satellites have become one of the main resources for\  Earth observation images because they are free of charge, have a great spatial coverage and high temporal revisit. Sentinel-2 senses the same location providing different spatial resolutions as well as generating a multi-spectral image with 13 bands of 10, 20, and 60 m/pixel. In this work, we propose a single-image super-resolution model based on convolutional neural networks that enhances the low-resolution bands (20 m and 60 m) to reach the maximal resolution sensed (10 m) at the same time, whereas other approaches provide two independent models for each group of LR bands. Our proposed model, named Sen2-RDSR, is made up of Residual in Residual blocks that produce two final outputs at maximal resolution, one for 20 m/pixel bands and the other for 60 m/pixel bands. The training is done in two stages, first focusing on 20 m bands and then on the 60 m bands. Experimental results using 6 quality metrics (RMSE, SRE, SAM, PSNR, SSIM, ERGAS) show that our model has superior performance compared to other state-of-the-art approaches, and it is very effective and suitable as a preliminary step for land and coastal applications, as studies involving pixel-based classification for Land-Use-Land-Cover or the generation of vegetation indices.

}, author = {Luis Salgueiro and Javier Marcello and Ver{\'o}nica Vilaplana} } @conference {cPuig-Sitjes21, title = {Spatio-temporal Detection and Tracking of Thermal Events on the Plasma Facing Components of Wendelstein 7-X}, booktitle = {4th IAEA Technical Meeting on Fusion Data Processing, Validation and Analysis}, year = {2021}, month = {11/2021}, publisher = {iaea.org}, organization = {iaea.org}, address = {Shanghai (online)}, abstract = {

In steady-state fusion devices like Wendelstein 7-X (W7-X), the active control of heat loads is mandatory to attain long-plasma operation. An intelligent feedback control system that mitigates the risk of overheating is required to avoid a premature plasma termination by the safety system. To keep the plasma within the safe operational limits of the plasma facing components, the feedback control system must be informed of the ongoing thermal events and their evolution in time. Then it can take effectives countermeasures to prevent the thermal events from reaching a critical point. These countermeasures may include reducing the heating power, changing the strike-line position or inducing detachment. With reaction times of the order of a hundred milliseconds, a fully automated real-time image analysis algorithm is required.
In this work, we present a spatio-temporal algorithm to detect, classify and track the thermal events observed by the thermography diagnostic on the plasma facing components of W7-X. The system detects and distinguishes between strike-lines and isolated hot spots as well as leading edges. The segmentation of the strike-line is specially challenging at W7-X. As a 3-dimensional helically-shaped stellarator equipped with 10 island divertors, the strike-lines have a complex heat load distribution with a high-dynamic range. The use of morphological tools and, in particular, the use of the Max-tree transform allow us to segment the thermal events in a hierarchical way preserving the inclusion relationship between different events, like hot spots and leading edges embedded in the strike-line structure. The thermal events are segmented for each frame and tracked over time in order to forecast their temporal evolution and to evaluate their risk. To this end, a spatio-temporal graph is built and spatio-temporal connected components are used to track the thermal events across the sequence frames. The spatio-temporal components in the graph are used to label the events in the sequence preserving temporal coherence and minimizing discontinuities, solving splits and merges. Spatio-temporal descriptors are then generated for each event to assess their risk.
The algorithm was tested offline on the infrared data acquired during the last operation phase OP1.2 and the results are presented here. Further work will follow to accelerate the code with GPUs to reach real-time processing and be ready to protect the water-cooled plasma facing components in the forthcoming operation phase OP2.

}, url = {https://conferences.iaea.org/event/251/contributions/20704/}, author = {Puig-Sitjes, A. and Casas, J. and Salembier, P. and Vizcarro, D. and Clemente, R. and Jakubowski, M. and Gao, Y. and W7-X Team} } @conference {cKazakos, title = {SynthRef: Generation of Synthetic Referring Expressions for Object Segmentation}, booktitle = {NAACL Visually Grounded Interaction and Language (ViGIL) Workshop}, year = {2021}, month = {06/2021}, address = {Virtual}, abstract = {

Recent advances in deep learning have brought significant progress in visual grounding tasks such as language-guided video object segmentation. However, collecting large datasets for these tasks is expensive in terms of annotation time, which represents a bottleneck. To this end, in our work we propose a novel method, namely SynthRef, for generating synthetic referring expressions for an image (or video frame), and we also present and disseminate the first large-scale dataset with synthetic referring expressions for video object segmentation. Our experiments demonstrate that by training with our synthetic dataset one can improve the ability of a model to generalize across different datasets, without any additional annotation cost. Moreover, our formulation allows its application to any object detection or segmentation dataset.

}, author = {Kazakos, Ioannis and Bellver-Bueno, M{\'\i}riam and Ventura, C. and Silberer, Carina and Xavier Gir{\'o}-i-Nieto} } @conference {cMora20, title = {Brain Tumor Segmentation using 3D-CNNs with Uncertainty Estimation}, booktitle = {MICCAI 2020 - Brain Lesion Workshop (BrainLes), Multimodal Brain Tumor Segmentation Challenge (BRATS)}, year = {2020}, month = {10/2020}, abstract = {

Automation of brain tumors in 3D magnetic resonance images (MRIs) is key to assess the diagnostic and treatment of the disease. In recent years, convolutional neural networks (CNNs) have shown improved results in the task. However, high memory consumption is still a problem in 3D-CNNs. Moreover, most methods do not include uncertainty information, which is specially critical in medical diagnosis. This work proposes a 3D encoder-decoder architecture, based on V-Net which is trained with patching techniques to reduce memory consumption and decrease the effect of unbalanced data. We also introduce voxel-wise uncertainty, both epistemic and aleatoric using test-time dropout and data-augmentation respectively. Uncertainty maps can provide extra information to expert neurologists, useful for detecting when the model is not confident on the provided segmentation.

}, author = {Laura Mora and Ver{\'o}nica Vilaplana} } @conference {cVentura20, title = {Can Everybody Sign Now? Exploring Sign Language Video Generation from 2D Poses}, booktitle = {ECCV 2020 Workshop on Sign Language recognition, Production and Translation (SLRTP)}, year = {2020}, month = {08/2020}, abstract = {

Recent work have addressed the generation of human poses represented by 2D/3D coordinates of human joints for sign language. We use the state of the art in Deep Learning for motion transfer and evaluate them on How2Sign, an American Sign Language dataset, to generate videos of signers performing sign language given a 2D pose skeleton. We evaluate the generated videos quantitatively and qualitatively showing that the current models are not enough to generated adequate videos for Sign Language due to lack of detail in hands.

}, author = {Lucas Ventura and Amanda Duarte and Xavier Gir{\'o}-i-Nieto} } @conference {cGonzalez-i-Calabuig, title = {Curriculum Learning for Recurrent Video Object Segmentation}, booktitle = {ECCV 2020 Women in Computer Vision Workshop}, year = {2020}, month = {08/2020}, abstract = {

Video object segmentation can be understood as a sequence-to-sequence task that can benefit from the curriculum learning strategies for better and faster training of deep neural networks.\ This work explores different schedule sampling and frame skipping variations to significantly improve the performance of a recurrent architecture.\ Our results on the car class of the KITTI-MOTS challenge indicate that, surprisingly, an inverse schedule sampling is a better option than a classic forward one. Also, that a progressive skipping of frames during training is beneficial, but only when training with the ground truth masks instead of the predicted ones.



Curriculum Learning for Recurrent Video Object Segmentation from Universitat Polit{\`e}cnica de Catalunya
}, author = {Gonzalez-i-Calabuig, Maria and Ventura, C. and Xavier Gir{\'o}-i-Nieto} } @mastersthesis {xGonzalez-i-Calabuig20, title = {Curriculum Learning for Recurrent Video Object Segmentation}, year = {2020}, abstract = {

Video object segmentation (VOS) is a computer vision task that aims at determining\ the pixels of an object of interest along a video sequence. This thesis explores different\ curriculum learning strategies for a deep neural network trained to solve this task.

Curriculum learning defines a methodology where the training data are not randomly presented to the model, instead, they are organized in a meaningful way. Simple concepts are first presented and gradually become more complex. Four different\ curriculum strategies are explored: schedule sampling, frame skipping, the effect of\ temporal and spatial recurrence variations and loss penalization by the object{\textquoteright}s area.

This work focuses on the RVOS neural architecture, a recurrent architecture originally tested on the DAVIS and YouTube-VOS datasets for one-shot video object segmentation, over the cars class of the KITTI-MOTS dataset. Even though this architecture is a fast solution for the VOS task, the model struggles with the KITTI-MOTS\ dataset, whose videos are more crowded and challenging.

For the schedule sampling curriculum, both the classic and inverse implementations are evaluated. Results show how inverse schedule sampling strategies improve\ the model{\textquoteright}s performance instead of the classic approach, the forward one. The different frame skipping schemes are also beneficial, but only when training with the\ ground truth mask instead of the predicted ones. Lastly, both the curriculums that\ vary the temporal and spatial recurrence or penalize the loss by the object{\textquoteright}s area have\ shown poor model{\textquoteright}s performance.

These results show how curriculum learning strategies affect greatly the performance of recurrent neural networks. Moreover, the results on the inverse schedule\ sampling and frame skipping strategies invite to further explore this schemes to exploit\ their benefits.




Curriculum Learning for Recurrent Video Object Segmentationfrom\ Universitat Polit{\`e}cnica de Catalunya
}, author = {Gonzalez-i-Calabuig, Maria}, editor = {Xavier Gir{\'o}-i-Nieto and Ventura, C.} } @article {aGene-Molac, title = {Fruit detection and 3D location using instance segmentation neural networks and structure-from-motion photogrammetry}, journal = {Computers and Electronics in Agriculture}, volume = {169}, year = {2020}, month = {02/2020}, abstract = {

The development of remote fruit detection systems able to identify and 3D locate fruits provides opportunities to improve the efficiency of agriculture management. Most of the current fruit detection systems are based on 2D image analysis. Although the use of 3D sensors is emerging, precise 3D fruit location is still a pending issue. This work presents a new methodology for fruit detection and 3D location consisting of: (1) 2D fruit detection and segmentation using Mask R-CNN instance segmentation neural network; (2) 3D point cloud generation of detected apples using structure-from-motion (SfM) photogrammetry; (3) projection of 2D image detections onto 3D space; (4) false positives removal using a trained support vector machine. This methodology was tested on 11 Fuji apple trees containing a total of 1455 apples. Results showed that, by combining instance segmentation with SfM the system performance increased from an F1-score of 0.816 (2D fruit detection) to 0.881 (3D fruit detection and location) with respect to the total amount of fruits. The main advantages of this methodology are the reduced number of false positives and the higher detection rate, while the main disadvantage is the high processing time required for SfM, which makes it presently unsuitable for real-time work. From these results, it can be concluded that the combination of instance segmentation and SfM provides high performance fruit detection with high 3D data precision. The dataset has been made publicly available and an interactive visualization of fruit detection results is accessible at http://www.grap.udl.cat/documents/photogrammetry_fruit_detection.html

}, keywords = {Fruit detection, Fruit location, Mask R-CNN, Structure-from-motion, Terrestrial remote sensing}, issn = {ISSN: 0168-1699}, doi = {https://doi.org/10.1016/j.compag.2019.105165}, url = {https://doi.org/10.1016/j.compag.2019.105165}, author = {Gen{\'e}-Mola, Jordi and Sanz, Ricardo and Rosell-Polo, Joan R. and Morros, J.R. and Ruiz-Hidalgo, J. and Ver{\'o}nica Vilaplana and Gregorio, Eduard} } @article {aGene-Mola20, title = {Fuji-SfM dataset: A collection of annotated images and point clouds for Fuji apple detection and location using structure-from-motion photogrammetry}, volume = {Data in Brief}, year = {2020}, month = {06/2020}, keywords = {Fruit detection, Mask R-CNN, Photogrammetry, Structure-from-motion, Terrestrial remote sensing, Yield mapping, Yield prediction}, doi = {https://doi.org/10.1016/j.dib.2020.105591}, author = {Gen{\'e}-Mola, Jordi and Sanz, Ricardo and Rosell-Polo, Joan R. and Morros, J.R. and Ruiz-Hidalgo, J. and Ver{\'o}nica Vilaplana and Gregorio, Eduard} } @article {xGiro-i-Nieto20a, title = {Image Segmentation with Deep Learning}, year = {2020}, abstract = {

Image segmentation is a classic computer vision task that aims at labeling pixels with semantic classes. These slides provide an overview of the basic approaches applied from the deep learning field to tackle this challenge and presents the basic subtasks (semantic, instance and panoptic segmentation) and related datasets.

Presented at the International Summer School on Deep Learning (ISSonDL) 2020 held online and organized by the University of Gdansk (Poland) between the 30th August and 2nd September.

Image Segmentation with Deep Learning - Xavier Giro \& Carles Ventura - ISSonDL 2020 from Universitat Polit{\`e}cnica de Catalunya
}, author = {Xavier Gir{\'o}-i-Nieto and Ventura, C.} } @article {aCasamitjanab, title = {NeAT: a nonlinear analysis toolbox for neuroimaging}, journal = {Neuroinformatics}, year = {2020}, month = {03/2020}, abstract = {

NeAT is a modular, flexible and user-friendly neuroimaging analysis toolbox for modeling linear and nonlinear effects overcoming the limitations of the standard neuroimaging methods which are solely based on linear models. NeAT provides a wide range of statistical and machine learning non-linear methods for model estimation, several metrics based on curve fitting and complexity for model inference and a graphical user interface (GUI) for visualization of results. We illustrate its usefulness on two study cases where non-linear effects have been previously established. Firstly, we study the nonlinear effects of Alzheimer{\textquoteright}s disease on brain morphology (volume and cortical thickness). Secondly, we analyze the effect of the apolipoprotein APOE-ε4 genotype on brain aging and its interaction with age. NeAT is fully documented and publicly distributed at https://imatge-upc.github.io/neat-tool/.

}, keywords = {Alzheimer{\textquoteright}s disease, APOE, GAM, GLM, inference, neuroimaging, nonlinear., SVR}, doi = {10.1007/s12021-020-09456-w}, url = {https://link.springer.com/article/10.1007/s12021-020-09456-w}, author = {Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and Santi Puch and Asier Aduriz and Carlos Lopez and G. Operto and R. Cacciaglia and C. Falcon and J.L. Molinuevo and Juan D. Gispert} } @article {aCasamitjanac, title = {Projection to Latent Spaces disentangles pathological effects on brain morphology in the asymptomatic phase of Alzheimer{\textquoteright}s disease}, journal = {Frontiers in Neurology, section Applied Neuroimaging}, volume = {11}, year = {2020}, month = {07/2020}, chapter = {648}, abstract = {

Alzheimer{\textquoteright}s disease (AD) continuum is defined as a cascade of several neuropathological processes that can be measured using biomarkers such as cerebrospinal fluid (CSF) levels of Aβ, p-tau and t-tau. In parallel, brain anatomy can be characterized through imaging techniques such as magnetic resonance imaging (MRI). In this work, we relate both sets of measurements seeking associations between biomarkers and brain structure that can be indicative of AD progression. The goal is to uncover underlying multivariate effects of AD pathology on regional brain morphological information. For this purpose, we use the projection to latent structures (PLS)\ method. Using PLS, we find a low dimensional latent space that best describes the covariance between both sets of measurements on the same subjects. Possible confounder effects (age and sex) on brain morphology are included in the model and regressed out using an orthogonal PLS model. We look for statistically significant correlations between brain morphology and CSF biomarkers that explain part of the volumetric variance at each region-of-interest (ROI). Furthermore, we use a clustering technique to discover a small set of CSF-related patterns describing the AD continuum. We apply this technique to the study of subjects in the whole AD continuum from the preclinical asymptomatic stages all through to the symptomatic groups. Subsequent analyses involve splitting the course of the disease into diagnostic categories: cognitively unimpaired subjects (CU), mild cognitive impaired subjects (MCI) and dementia subjects (AD-dementia) where all symptoms are due to AD.

}, keywords = {Alzheimer{\textquoteright}s disease, brain morphology, CSF biomarkers, Latent model, PLS, preclinical AD}, author = {Adri{\`a} Casamitjana and Paula Petrone and Jose Luis Molinuevo and Juan D. Gispert and Ver{\'o}nica Vilaplana} } @article {aSalgueiro, title = {Super-Resolution of Sentinel-2 Imagery Using Generative Adversarial Networks}, journal = {Remote Sensing}, volume = {12}, year = {2020}, month = {01/2020}, abstract = {

Sentinel-2 satellites provide multi-spectral optical remote sensing images with four bands at 10 m of spatial resolution. These images, due to the open data distribution policy, are becoming an important resource for several applications. However, for small scale studies, the spatial detail of these images might not be sufficient. On the other hand, WorldView commercial satellites offer multi-spectral images with a very high spatial resolution, typically less than 2 m, but their use can be impractical for large areas or multi-temporal analysis due to their high cost. To exploit the free availability of Sentinel imagery, it is worth considering deep learning techniques for single-image super-resolution tasks, allowing the spatial enhancement of low-resolution (LR) images by recovering high-frequency details to produce high-resolution (HR) super-resolved images. In this work, we implement and train a model based on the Enhanced Super-Resolution Generative Adversarial Network (ESRGAN) with pairs of WorldView-Sentinel images to generate a super-resolved multispectral Sentinel-2 output with a scaling factor of 5. Our model, named RS-ESRGAN, removes the upsampling layers of the network to make it feasible to train with co-registered remote sensing images. Results obtained outperform state-of-the-art models using standard metrics like PSNR, SSIM, ERGAS, SAM and CC. Moreover, qualitative visual analysis shows spatial improvements as well as the preservation of the spectral information, allowing the super-resolved Sentinel-2 imagery to be used in studies requiring very high spatial resolution.

}, author = {Luis Salgueiro and Javier Marcello and Ver{\'o}nica Vilaplana} } @conference {cCombaliad, title = {Uncertainty Estimation in Deep Neural Networks for Dermoscopic Image Classification}, booktitle = {CVPR 2020, ISIC Skin Image Analysis Workshop}, year = {2020}, month = {2020}, abstract = {

The high performance of machine learning algorithms for the task of skin lesion classification has been shown over the past few years. However, real-world implementations are still scarce. One of the reasons could be that most methods do not quantify the uncertainty in the predictions and are not able to detect data that is anomalous or significantly different from that used in training, which may lead to a lack of confidence in the automated diagnosis or errors in the interpretation of results.

In this work, we explore the use of uncertainty estimation techniques and metrics for deep neural networks based on Monte-Carlo sampling and apply them to the problem of skin lesion classification on data from ISIC Challenges 2018 and 2019.

Our results show that uncertainty metrics can be successfully used to detect difficult and out-of-distribution samples.

}, author = {Marc Combalia and Ferran Hueto and Susana Puig and Josep Malvehy and Ver{\'o}nica Vilaplana} } @conference {cMoliner, title = {Weakly Supervised Semantic Segmentation for Remote Sensing Hyperspectral Imaging}, booktitle = {International Conference on Acoustics, Speech, and Signal Processing (ICASSP 2020)}, year = {2020}, month = {05/2020}, abstract = {

This paper studies the problem of training a semantic segmentation neural network with weak annotations, in order to be applied in aerial vegetation images from Teide National Park. It proposes a Deep Seeded Region Growing system which consists on training a semantic segmentation network from a set of seeds generated by a Support Vector Machine. A region growing algorithm module is applied to the seeds to progressively increase the pixel-level supervision. The proposed method performs better than an SVM, which is one of the most popular segmentation tools in remote sensing image applications.

}, author = {Eloi Moliner and Luis Salgueiro and Ver{\'o}nica Vilaplana} } @conference {cCombaliac, title = {BCN20000: Dermoscopic Lesions in the Wild}, booktitle = {International Skin Imaging Collaboration (ISIC) Challenge on Dermoscopic Skin Lesion Analysis 2019}, year = {2019}, month = {10/2019}, abstract = {

This article summarizes the BCN20000 dataset, composed of 19424 dermoscopic images of skin lesions captured from 2010 to 2016 in the facilities of the Hospital Cl{\'\i}nic in Barcelona. With this dataset, we aim to study the problem of unconstrained classification of dermoscopic images of skin cancer, including lesions found in hard-to-diagnose locations (nails and mucosa), large lesions which do not fit in the aperture of the dermoscopy device, and hypo-pigmented lesions. The BCN20000 will be provided to the participants of the ISIC Challenge 2019 \cite{ISIC2019}, where they will be asked to train algorithms to classify dermoscopic images of skin cancer automatically.

}, author = {Marc Combalia and Noel C. F. Codella and Veronica Rotemberg and Brian Helba and Ver{\'o}nica Vilaplana and Ofer Reiter and Cristina Carrera and Alicia Barreiro and Allan C. Halpern and Susana Puig and Josep Malvehy} } @article {aWang19, title = {Benchmark on Automatic 6-month-old Infant Brain Segmentation Algorithms: The iSeg-2017 Challenge}, journal = {IEEE Transactions on Medical Imaging}, year = {2019}, month = {2019/2/27}, abstract = {

Accurate segmentation of infant brain magnetic resonance (MR) images into white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) is an indispensable foundation for early studying of brain growth patterns and morphological changes in neurodevelopmental disorders. Nevertheless, in the isointense phase (approximately 6-9 months of age), due to inherent myelination and maturation process, WM and GM exhibit similar levels of intensity in both T1-weighted (T1w) and T2-weighted (T2w) MR images, making tissue segmentation very challenging. Despite many efforts were devoted to brain segmentation, only few studies have focused on the segmentation of 6-month infant brain images. With the idea of boosting methodological development in the community, iSeg-2017 challenge (http://iseg2017.web.unc.edu) provides a set of 6-month infant subjects with manual labels for training and testing the participating methods. Among the 21 automatic segmentation methods participating in iSeg-2017, we review the 8 top-ranked teams, in terms of Dice ratio, modified Hausdorff distance and average surface distance, and introduce their pipelines, implementations, as well as source codes. We further discuss limitations and possible future directions. We hope the dataset in iSeg-2017 and this review article could provide insights into methodological development for the community.

}, doi = {10.1109/TMI.2019.2901712}, author = {Li Wang and Dong Nie and Guannan Li and Elodie Puybareau and Jose Dolz and Qian Zhang and Fan Wang and Jing Xia and Zhengwang Wu and Jiawei Chen and Kim-HanThung and Toan Duc Bui and Jitae Shin and Guodong Zeng and Guoyan Zheng and Vladimir S. Fonov and Andrew Doyle and Yongchao Xu and Pim Moeskops and Josien Pluim and Christian Desrosiers and Ismail Ben Ayed and Gerard Sanroma and Oualid Benkarim and Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and Weili Lin and Gang Li and Dinggang Shen} } @mastersthesis {xDomenech19, title = {Clasificaci{\'o}n de im{\'a}genes dermatosc{\'o}picas utilizando Redes Neuronales Convolucionales e informaci{\'o}n de metadatos}, year = {2019}, abstract = {

Convolutional Neural Networks (CNNs) is a technology that is evolving very quickly. The CNNs are used in image recognition to improve computer vision systems in image classification, object detection and segmentation tasks. For all the mentioned features we can apply the CNN in the field of medicine to automate the techniques of obtaining diagnosis and facilitate the tasks of doctors.

The purpose of this project is to classify images of different skin lesions in order to detect possible diseases such as skin cancer (melanoma) through CNNs and metadata information. The images used in this project have been provided by the Dermatology Department of the Clinical Hospital of Barcelona

}, author = {Teresa Domenech}, editor = {Ver{\'o}nica Vilaplana} } @mastersthesis {xTarres19, title = {Clasificaci{\'o}n de lesiones de piel con un ensemble de redes neuronales residuales}, year = {2019}, abstract = {

Convolutional Neural Networks have gained popularity in the recent years due to their performance regarding image analysis, both in classification and segmentation. Especially in the medical field, it is increasingly common to use automatic techniques to help specialists with the diagnosis.

In this thesis, the problem of skin lesion classification is studied. The study is based on the ISIC Challenges, given the collaboration with Hospital Cl{\'\i}nic de Barcelona, and we help in the development of the database for the ISIC Challenge 2019.

One of the key points of the development is obtaining a model that manages to classify with accuracy a database provided. To do so, we study residual neural networks and an ensemble of them to further improve the results.

The purpose of this project, therefore is the study, analysis and evaluation of the variants and modifications of residual neural networks so that it adapts to our problem using an ensemble of them. In the process, the neural network will have to tackle the problem of class imbalance

}, author = {Laia Tarr{\'e}s}, editor = {Ver{\'o}nica Vilaplana and Marc Combalia} } @conference {cIsart, title = {CNN-based bacilli detection in sputum samples for tuberculosis diagnosis}, booktitle = {International Symposium on Biomedical Imaging (ISBI 2019)}, year = {2019}, month = {04/2019}, abstract = {

Tuberculosis (TB) is one of the infectious diseases that causes more deaths in low and middle-income countries. A low-cost method to diagnose TB consists in analyzing sputum smear samples through microscope observation. Manual identification and counting of bacilli is a very time consuming task and the sensitivity of the diagnosis depends on the availability of skilled technicians. We propose a computer vision technique based on a convolutional neural network (CNN) to automatically segment and count bacilli in sputum samples and predict the infection level.

}, author = {Antoni Isart and Mateu Espasa and Ver{\'o}nica Vilaplana and Elisa Sayrol} } @conference {cSalgueiro, title = {Comparative study of upsampling methods for super-resolution in remote sensing}, booktitle = {International Conference on Machine Vision}, year = {2019}, month = {11/2019}, abstract = {

Many remote sensing applications require high spatial resolution images, but the elevated cost of these images makes some studies unfeasible. Single-image super-resolution algorithms can improve the spatial resolution of a low-resolution image by recovering feature details learned from pairs of low-high resolution images. In this work, several configurations of ESRGAN, a state-of-the-art algorithm for image super-resolution are tested. We make a comparison between several scenarios, with different modes of upsampling and channels involved.\  The best results are obtained training a model with RGB-IR channels and using progressive upsampling.\ 

}, keywords = {deep learning, Remote sensing, Super-resolution, WorldView-2}, author = {Luis Salgueiro and Javier Marcello and Ver{\'o}nica Vilaplana} } @mastersthesis {xBalibrea19, title = {Deep learning for semantic segmentation of airplane hyperspectral imaging}, year = {2019}, abstract = {

Given their success, both qualitative and quantitative, Deep Neural Networks have been used to approach classification and segmentation problems for images, especially during these last few years where it has been possible to design computers with sufficient capacity to make quick and efficient experiments.

In this work, we will study the use of two Convolutional Neural Networks (CNNs) to segment the ground of a land section of Maspalomas{\textquoteright} Park using an image taken by the flight of an airplane.

The comparison will be made in terms of computational cost, complexity and results that will be obtained while testing different algorithms, loss functions or optimizers and also while tuning some other parameters. The results will also be compared with a past work done with the same dataset but another methodology (SVM).

}, author = {Mar Balibrea}, editor = {Luis Salgueiro and Ver{\'o}nica Vilaplana} } @conference {cCasamitjana19, title = {Detection of Amyloid Positive Cognitively unimpaired individuals using voxel-based machine learning on structural longitudinal brain MRI}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2019}, month = {07/2019}, author = {Adri{\`a} Casamitjana and P. Petrone and C. Falcon and M. Artigues and G. Operto and R. Cacciaglia and J.L. Molinuevo and Ver{\'o}nica Vilaplana and J.D. Gispert} } @article {aCasamitjana19, title = {Detection of Amyloid-Positive Cognitively Unimpaired Individuals Using Voxel-Based Machine Learning on Structural Longitudinal Brain MRI}, journal = {Alzheimer{\textquoteright}s \& Dementia}, volume = {15}, year = {2019}, month = {07/2019}, chapter = {752}, abstract = {

Magnetic resonance imaging (MRI) has unveiled specific AD alterations at different stages of the AD pathophysiologic continuum that constitutes what has been established as the {\textquoteleft}AD signature{\textquoteright}. To what extent MRI can detect amyloid-related cerebral changes from structural MRI in unimpaired individuals is still an area open for exploration.

}, issn = {1552-5260}, doi = {10.1016/j.jalz.2019.06.2796}, author = {Adri{\`a} Casamitjana and P. Petrone and C. Falcon and M. Artigues and G. Operto and R. Cacciaglia and J.L. Molinuevo and Ver{\'o}nica Vilaplana and J.D. Gispert} } @conference {cCombaliab, title = {Digitally Stained Confocal Microscopy through Deep Learning}, booktitle = {International Conference on Medical Imaging with Deep Learning (MIDL 2019)}, year = {2019}, month = {07/2019}, address = {London}, abstract = {

Specialists have used confocal microscopy in the ex-vivo modality to identify tumors with\ an overall sensitivity of 96.6\% and specicity of 89.2\%. However, this technology hasn{\textquoteright}t\ established yet in the standard clinical practice because most pathologists lack the knowledge to interpret its output. In this paper we propose a combination of deep learning and\ computer vision techniques to digitally stain confocal microscopy images into H\&E-like\ slides, enabling pathologists to interpret these images without specic training. We use a\ fully convolutional neural network with a multiplicative residual connection to denoise the\ confocal microscopy images, and then stain them using a Cycle Consistency Generative\ Adversarial Network.

}, author = {Marc Combalia and Javiera P{\'e}rez-Anker and Adriana Garc{\'\i}a-Herrera and Ll{\'u}cia Alos and Ver{\'o}nica Vilaplana and Ferran Marques and Susana Puig and Josep Malvehy} } @article {aGene-Molab, title = {Fruit Detection in an Apple Orchard Using a Mobile Terrestrial Laser Scanner}, journal = {Biosystems Engineering}, volume = {187}, year = {2019}, month = {09/2019}, chapter = {171}, abstract = {

The development of reliable fruit detection and localization systems provides an opportunity to improve the crop value and management by limiting fruit spoilage and optimized harvesting practices. Most proposed systems for fruit detection are based on RGB cameras and thus are affected by intrinsic constraints, such as variable lighting conditions. This work presents a new technique that uses a mobile terrestrial laser scanner (MTLS) to detect and localise Fuji apples. An experimental test focused on Fuji apple trees (Malus domestica Borkh. cv. Fuji) was carried out. A 3D point cloud of the scene was generated using an MTLS composed of a Velodyne VLP-16 LiDAR sensor synchronized with an RTK-GNSS satellite navigation receiver. A reflectance analysis of tree elements was performed, obtaining mean apparent reflectance values of 28.9\%, 29.1\%, and 44.3\% for leaves, branches and trunks, and apples, respectively. These results suggest that the apparent reflectance parameter (at 905 nm wavelength) can be useful to detect apples. For that purpose, a four-step fruit detection algorithm was developed. By applying this algorithm, a localization success of 87.5\%, an identification success of 82.4\%, and an F1-score of 0.858 were obtained in relation to the total amount of fruits. These detection rates are similar to those obtained by RGB-based systems, but with the additional advantages of providing direct 3D fruit location information, which is not affected by sunlight variations. From the experimental results, it can be concluded that LiDAR-based technology and, particularly, its reflectance information, has potential for remote apple detection and 3D location.

}, issn = {1537-5110}, doi = {10.1016/j.biosystemseng.2019.08.017}, url = {https://authors.elsevier.com/c/1Zmc45Tbkk9EHW}, author = {Gen{\'e}-Mola, Jordi and Gregorio, Eduard and Guevara, Javier and Auat Cheein, Fernando and Sanz, Ricardo and Escol{\`a}, Alexandre and Llorens Calveras, Jordi and Morros, J.R. and Ruiz-Hidalgo, J. and Ver{\'o}nica Vilaplana and Rosell-Polo, Joan R.} } @mastersthesis {xDomingo19, title = {Interpretability of Deep Learning Models}, year = {2019}, abstract = {

In recent years we have seen growth on interest for Deep Learning (DL) algorithms on a variety of problems, due to their outstanding performance. This is more palpable on a multitude of elds, where self learning algorithms are becoming indispensable tools to help professionals solve complex problems.

However as these models are getting better, they also tend to be more complex and are sometimes referred to as "Black Boxes". The lack of explanations for the resulting predictions and the inability of humans to understand those decisions seems problematic.

In this project, dierent methods to increase the interpretability of Deep Neural Networks (DNN) such as Convolutional Neural Network (CNN) are studied. Additionally, we evaluate how these interpretability methods or techniques can be implemented, measured and applied to real-world problems, by creating a python ToolBox.

}, author = {Pau Domingo}, editor = {Ver{\'o}nica Vilaplana} } @article {aGene-Molaa, title = {KFuji RGB-DS database: Fuji apple multi-modal images for fruit detection with color, depth and range-corrected IR data}, journal = {Data in Brief}, year = {2019}, month = {07/2019}, abstract = {

This article contains data related to the research article entitle {\textquotedblleft}Multi-modal Deep Learning for Fruit Detection Using RGB-D Cameras and their Radiometric Capabilities{\textquotedblright} [1]. The development of reliable fruit detection and localization systems is essential for future sustainable agronomic management of high-value crops. RGB-D sensors have shown potential for fruit detection and localization since they provide 3D information with color data. However, the lack of substantial datasets is a barrier for exploiting the use of these sensors. This article presents the KFuji RGB-DS database which is composed by 967 multi-modal images of Fuji apples on trees captured using Microsoft Kinect v2 (Microsoft, Redmond, WA, USA). Each image contains information from 3 different modalities: color (RGB), depth (D) and range corrected IR intensity (S). Ground truth fruit locations were manually annotated, labeling a total of 12,839 apples in all the dataset. The current dataset is publicly available at http://www.grap.udl.cat/publicacions/datasets.html.

}, keywords = {Depth cameras; RGB-D, Fruit detection, Fruit reflectance, Fuji apple, Multi-modal dataset}, doi = {10.1016/j.dib.2019.104289}, author = {Gen{\'e}-Mola, Jordi and Ver{\'o}nica Vilaplana and Rosell-Polo, Joan R. and Morros, J.R. and Ruiz-Hidalgo, J. and Gregorio, Eduard} } @article {aSala, title = {Measuring traffic lane-changing by converting video into space-time still images}, journal = {Computer-Aided Civil and Infrastructure Engineering}, year = {2019}, month = {01/2019}, abstract = {

Empirical data is needed in order to extend\ our knowledge of traffic behavior. Video recordings are\ used to enrich typical data from loop detectors. In this\ context, data extraction from videos becomes a\ challenging task. Setting automatic video processing\ systems is costly, complex, and the accuracy achieved is\ usually not enough to improve traffic flow models. In\ contrast "visual" data extraction by watching the\ recordings requires extensive human intervention.

A semi-automatic video processing methodology to\ count lane-changing in freeways is proposed. The method\ allows counting lane changes faster than with the visual\ procedure without falling into the complexities and\ errors of full automation. The method consists in\ converting the video into a set of space-time still images,\ from where to visually count. This methodology has been\ tested at several freeway locations near Barcelona\ (Spain) with good results

}, doi = {https://doi.org/10.1111/mice.12430}, url = {https://onlinelibrary.wiley.com/doi/full/10.1111/mice.12430}, author = {Marcel Sala and Francesc Soriguera and Kevin Huillca and Ver{\'o}nica Vilaplana} } @article {aGene-Mola, title = {Multi-modal Deep Learning for Fuji Apple Detection Using RGB-D Cameras and their Radiometric Capabilities}, journal = {Computers and Electronics in Agriculture}, volume = {162}, year = {2019}, month = {07/2019}, chapter = {689-698}, abstract = {

Fruit detection and localization will be essential for future agronomic management of fruit crops, with applications in yield prediction, yield mapping and automated harvesting. RGB-D cameras are promising sensors for fruit detection given that they provide geometrical information with color data. Some of these sensors work on the principle of time-of-flight (ToF) and, besides color and depth, providethe backscatter signal intensity. However, this radiometric capability has not been exploited for fruit detection applications. This workpresents the KFuji RGB-DS database, composed of 967 multi-modal images containing a total of 12,839 Fuji apples. Compilation of th\ database allowed a study of the usefulness of fusing RGB-D and radiometric information obtained with Kinect v2 for fruit detection. Todo so, the signal intensity was range corrected to overcome signal attenuation, obtaining an image that was proportional to the reflectanceof the scene. A registration between RGB, depth and intensity images was then carried out. The Faster R-CNN model was adapted foruse with five-channel input images: color (RGB), depth (D) and range-corrected intensity signal (S). Results show an improvement of4.46\% in F1-score when adding depth and range-corrected intensity channels, obtaining an F1-score of 0.898 and an AP of 94.8\% whenall channels are used. From our experimental results, it can be concluded that the radiometric capabilities of ToF sensors give valuableinformation for fruit detection.

}, keywords = {Agricultural robotics, Convolutional Neural Networks, Fruit detection, Fruit reflectance, Multi-modal faster R-CNN, RGB-D}, doi = {10.1016/j.compag.2019.05.016}, author = {Gen{\'e}-Mola, Jordi and Ver{\'o}nica Vilaplana and Rosell-Polo, Joan R. and Morros, J.R. and Ruiz-Hidalgo, J. and Gregorio, Eduard} } @article {aVentura, title = {Multiresolution co-clustering for uncalibrated multiview segmentation}, journal = {Signal Processing: Image Communication}, year = {2019}, abstract = {

We propose a technique for coherently co-clustering uncalibrated views of a scene\ with a contour-based representation. Our work extends the previous framework,\ an iterative algorithm for segmenting sequences with small variations, where the\ partition solution space is too restrictive for scenarios where consecutive images\ present larger variations. To deal with a more flexible scenario, we present three\ main contributions. First, motion information has been considered both for\ region adjacency and region similarity. Second, a two-step iterative architecture\ is proposed to increase the partition solution space. Third, a feasible global\ optimization that allows to jointly process all the views has been implemented.\ In addition to the previous contributions, which are based on low-level features,\ we have also considered introducing higher level features as semantic information\ in the co-clustering algorithm. We evaluate these techniques on multiview and\ temporal datasets, showing that they outperform state-of-the-art approaches.

}, keywords = {Co-clustering techniques, Image segmentation, Multiview segmentation, Object segmentation}, doi = {10.1016/j.image.2019.04.010}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0923596518302054}, author = {Ventura, C. and David Varas and Ver{\'o}nica Vilaplana and Xavier Gir{\'o}-i-Nieto and Ferran Marques} } @conference {cMas, title = {Picking groups instead of samples: A close look at Static Pool-based Meta-Active Learning}, booktitle = {ICCV Workshop - MDALC 2019}, year = {2019}, month = {10/2019}, address = {Seoul, South Korea}, abstract = {

Active Learning techniques are used to tackle learning problems where obtaining training labels is costly. In this work we use Meta-Active Learning to learn to select a subset of samples from a pool of unsupervised input for further annotation. This scenario is called Static Pool-based Meta-Active Learning. We propose to extend existing approaches by performing the selection in a manner that, unlike previous works, can handle the selection of each sample based on the whole selected subset.

}, doi = {http://dx.doi.org/10.1109/ICCVW.2019.00171}, author = {Mas, Ignasi and Morros, J.R. and Ver{\'o}nica Vilaplana} } @unpublished {cRamon19, title = {Plug-and-Train Loss for Model-Based Single View 3D Reconstruction}, journal = {BMVA Technical Meeting: 3D vision with Deep Learning}, year = {2019}, month = {02/2019}, publisher = {UPC}, address = {London, UK}, abstract = {

Obtaining 3D geometry from images is a well studied problem by the computer vision community. In the concrete case of a single image, a considerable amount of prior knowledge is often required to obtain plausible reconstructions. Recently, deep neural networks in combination with 3D morphable models (3DMM) have been used in order to address the lack of scene information, leading to more accurate results. Nevertheless, the losses employed during the training process are usually a linear combination of terms where the coefficients, also called hyperparameters, must be carefully tuned for each dataset to obtain satisfactory results. In this work we propose a hyperparameters-free loss that exploits the geometry of the problem for learning 3D reconstruction from a single image. The proposed formulation is not dataset dependent, is robust against very large camera poses and jointly optimizes the shape of the object and the camera pose.

Plug and-train Loss for Single View 3D Reconstruction from Universitat Polit{\`e}cnica de Catalunya
}, author = {Ramon, Eduard and Villar, Jordi and Ruiz, Guillermo and Batard, Thomas and Xavier Gir{\'o}-i-Nieto} } @conference {cPareto, title = {Prediction of a second clinical event in CIS patients by combining lesion and brain features}, booktitle = {Congress of the European Comitee for Treatment and Research in Multiple Sclerosis (ECTRIMS 2019)}, year = {2019}, month = {09/2019}, abstract = {

Prediction of a second clinical event in clinically isolated syndrome (CIS) patients, leading to clinically definite multiple sclerosis (CDMS), is still a matter of investigation. The aim of the current study was to predict conversion to CDMS after a first attack, by means of a machine-learning approach and MRI-derived brain features. For that purpose, lesion-based features (volume and distribution within brain lobes) as well as cortical thickness (CT) and deep grey matter volumes (DGMV) were used. The final goal was to determine which features were more frequently found in the classification between converters and non-converters.

}, author = {Deborah Pareto and Pau Vidal and M. Alberich and Carlos Lopez and C. Auger and M. Tintor{\'e} and X. Montalban and J. Sastre-Garriga and Ver{\'o}nica Vilaplana and Alex Rovira} } @article {aPetrone, title = {Prediction of amyloid pathology in cognitively unimpaired individuals using voxelwise analysis of longitudinal structural brain MRI}, journal = {Alzheimer{\textquoteright}s Research \& Therapy}, volume = {11}, year = {2019}, month = {12/2019}, abstract = {

Background: Magnetic resonance imaging (MRI) has unveiled specific alterations at different stages of Alzheimer{\textquoteright}s disease (AD) pathophysiologic continuum constituting what has been established as {\textquoteleft}AD signature{\textquoteright}. To what extent MRI can detect amyloid-related cerebral changes from structural MRI in cognitively unimpaired individuals is still an area open for exploration.

Method: Longitudinal 3D-T1 MRI scans were acquired from a subset of the ADNI cohort comprising 403 subjects: 79 controls (Ctrls), 50 preclinical AD (PreAD), 274 MCI and dementia due to AD (MCI/AD). Amyloid CSF was used as gold-standard measure with established cut-offs (\<192pg/mL) to establish diagnostic categories. Cognitively unimpaired individuals were defined as Ctrls if were amyloid negative and PreAD otherwise. The MCI/AD group was amyloid positive. Only subjects with the same diagnostic category at baseline and follow-up visits were considered for the study. Longitudinal morphometric analysis was performed using SPM12 to calculate Jacobian determinant maps. Statistical analysis was carried out on these jacobian maps to identify structural changes that were significantly different between diagnostic categories. A machine learning classifier was applied on Jacobian determinant maps to predict the presence of abnormal amyloid levels in cognitively unimpaired individuals. The performance of this classifier was evaluated using receiver operating characteristic curve analysis and as a function of the follow-up time between MRI scans. We applied a cost function to assess the benefit of using this classifier in the triaging of individuals in a clinical trial-recruitment setting.

Results: The optimal follow-up time for classification of Ctrls vs PreAD was Δt\>2.5 years and hence, only subjects within this temporal span are used for evaluation (15 Ctrls, 10 PreAD). The longitudinal voxel-based classifier achieved an AUC=0.87 (95\%CI:0.72-0.97). The brain regions that showed the highest discriminative power to detect amyloid abnormalities were the medial, inferior and lateral temporal lobes, precuneus, caudate heads, basal forebrain and lateral ventricles.

Conclusions: Our work supports that machine learning applied to longitudinal brain volumetric changes can be used to predict, with high precision, presence of amyloid abnormalities in cognitively unimpaired subjects. Used as a triaging method to identify a fixed number of amyloid positive individuals, this longitudinal voxelwise classifier is expected to avoid 55\% of unnecessary CSF and/or PET scans and reduce economic cost by 40\%.

}, doi = {https://doi.org/10.1186/s13195-019-0526-8}, url = {https://link.springer.com/article/10.1186/s13195-019-0526-8}, author = {Paula Petrone and Adri{\`a} Casamitjana and Carles Falcon and Miguel Artigues C{\`a}naves and G. Operto and R. Cacciaglia and Jose Luis Molinuevo and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cHerrera-Palacioa, title = {Recurrent Instance Segmentation using Sequences of Referring Expressions}, booktitle = {NeurIPS workshop on Visually Grounded Interaction and Language (ViGIL)}, year = {2019}, month = {09/2019}, address = {Vancouver, Canada}, abstract = {

The goal of this work is segmenting the objects in an image which are referred to by a sequence of linguistic descriptions (referring expressions). We propose a deep neural network with recurrent layers that output a sequence of binary masks, one for each referring expression provided by the user. The recurrent layers in the architecture allow the model to condition each predicted mask on the previous ones, from a spatial perspective within the same image. Our multimodal approach uses off-the-shelf architectures to encode both the image and the referring expressions. The visual branch provides a tensor of pixel embeddings that are concatenated with the phrase embeddings produced by a language encoder. Our experiments on the RefCOCO dataset for still images indicate how the proposed architecture successfully exploits the sequences of referring expressions to solve a pixel-wise task of instance segmentation.

Recurrent Instance Segmentation with Linguistic Referring Expressions from Universitat Polit{\`e}cnica de Catalunya
}, author = {Herrera-Palacio, Alba and Ventura, C. and Silberer, Carina and Sorodoc, Ionut-Teodor and Boleda, Gemma and Xavier Gir{\'o}-i-Nieto} } @mastersthesis {xHerrera-Palacio, title = {Recurrent Instance Segmentation with Linguistic Referring Expressions}, year = {2019}, abstract = {

The goal of this work is segmenting the object in an image or video which is referred to by a linguistic description (referring expression).\ We propose a deep neural network with recurrent layers that output a sequence of binary masks, one for each referring expression provided by the user.\ The recurrent layers in the architecture allow the model to condition each predicted mask on the previous ones, from a spatial perspective within the same image.\ Our multimodal approach uses off-the-shelf architectures to encode both the image and the referring expressions.\ The visual branch provides a tensor of pixel embeddings that are concatenated with the phrase embeddings produced by a language encoder.\ We focus our study on comparing different configurations to encode and combine the visual and linguistic representations.\ Our experiments on the RefCOCO dataset for still images indicate how the proposed architecture successfully exploits the referring expressions to solve a pixel-wise task of instance segmentation.

Recurrent Instance Segmentation with Linguistic Referring Expressions from Universitat Polit{\`e}cnica de Catalunya
}, author = {Herrera-Palacio, Alba}, editor = {Xavier Gir{\'o}-i-Nieto and Ventura, C. and Silberer, Carina} } @conference {cGullon, title = {Retinal lesions segmentation using CNNs and adversarial training}, booktitle = {International Symposium on Biomedical Imaging (ISBI 2019)}, year = {2019}, month = {04/2019}, abstract = {

Diabetic retinopathy (DR) is an eye disease associated with diabetes mellitus that affects retinal blood vessels. Early detection is crucial to prevent vision loss. The most common method for detecting the disease is the analysis of digital fundus images, which show lesions of small vessels and functional abnormalities.

Manual detection and segmentation of lesions is a time-consuming task requiring proficient skills. Automatic methods for retinal image analysis could help ophthalmologists in large-scale screening programs of population with diabetes mellitus allowing cost-effective and accurate diagnosis.

In this work we propose a fully convolutional neural network with adversarial training to automatically segment DR lesions in funduscopy images.\ 

}, author = {Nat{\`a}lia Gull{\'o}n and Ver{\'o}nica Vilaplana} } @conference {cVenturaa, title = {RVOS: End-to-End Recurrent Network for Video Object Segmentation}, booktitle = {CVPR}, year = {2019}, month = {06/2019}, publisher = {OpenCVF / IEEE}, organization = {OpenCVF / IEEE}, address = {Long Beach, CA, USA}, abstract = {

Multiple object video object segmentation is a challenging task, specially for the zero-shot case, when no object mask is given at the initial frame and the model has to find the objects to be segmented along the sequence. In our work, we propose RVOS, a recurrent network that is fully end-to-end trainable for multiple object video object segmentation, with a recurrence module working on two different domains: (i) the spatial, which allows to discover the different object instances within a frame, and (ii) the temporal, which allows to keep the coherence of the segmented objects along time. We train RVOS for zero-shot video object segmentation and are the first ones to report quantitative results for DAVIS-2017 and YouTube-VOS benchmarks. Further, we adapt RVOS for one-shot video object segmentation by using the masks obtained in previous time-steps as inputs to be processed by the recurrent module. Our model reaches comparable results to state-of-the-art techniques in YouTube-VOS benchmark and outperforms all previous video object segmentation methods not using online learning in the DAVIS-2017 benchmark.

RVOS: End-to-End Recurrent Network for Video Object Segmentation (CVPR 2019) from Universitat Polit{\`e}cnica de Catalunya



}, url = {http://openaccess.thecvf.com/content_CVPR_2019/html/Ventura_RVOS_End-To-End_Recurrent_Network_for_Video_Object_Segmentation_CVPR_2019_paper.html}, author = {Ventura, C. and M{\'\i}riam Bellver and Girbau, A. and Amaia Salvador and Marqu{\'e}s, F. and Xavier Gir{\'o}-i-Nieto} } @article {aCasamitjanaa, title = {Shared latent structures between imaging features and biomarkers in early stages of Alzheimer{\textquoteright}s disease: a predictive study}, journal = {IEEE Journal of Biomedical and Health Informatics}, year = {2019}, month = {08/2019}, abstract = {

Magnetic resonance imaging (MRI) provides high resolution brain morphological information and is used as a biomarker in neurodegenerative diseases. Population studies of brain morphology often seek to identify pathological structural changes related to different diagnostic categories (e.g: controls, mild cognitive impairment or dementia) which normally describe highly heterogeneous groups with a single categorical variable. Instead, multiple biomarkers are used as a proxy for pathology and are more powerful in capturing structural variability. Hence, using the joint modeling of brain morphology and biomarkers, we aim at describing structural changes related to any brain condition by means of few underlying processes. In this regard, we use a multivariate approach based on Projection to Latent Structures in its regression variant (PLSR) to study structural changes related to aging and AD pathology. MRI volumetric and cortical thickness measurements are used for brain morphology and cerebrospinal fluid (CSF) biomarkers (t-tau, p-tau and amyloid-beta) are used as a proxy for AD pathology. By relating both sets of measurements, PLSR finds a low-dimensional latent space describing AD pathological effects on brain structure. The proposed framework allows to separately model aging effects on brain morphology as a confounder variable orthogonal to the pathological effect. The predictive power of the associated latent spaces (i.e. the capacity of predicting biomarker values) is assessed in a cross-validation framework.\ 

}, keywords = {CSF biomarkers, Latent model, MRI, PLS, preclinical AD}, doi = {10.1109/JBHI.2019.2932565}, author = {Adri{\`a} Casamitjana and Paula Petrone and J.L. Molinuevo and Juan D. Gispert and Ver{\'o}nica Vilaplana} } @article {aKuijf, title = {Standardized Assessment of Automatic Segmentation of White Matter Hyperintensities; Results of the WMH Segmentation Challenge}, journal = {IEEE Transactions on Medical Imaging}, year = {2019}, month = {03/2019}, abstract = {

Quantification of white matter hyperintensities (WMH) of presumed vascular origin is of key\ importance in many neurological research studies. Advanced\ measurements are obtained from manual segmentations on brain\ MR images, which is a laborious procedure. Automatic WMH\ segmentation methods exist, but a standardized comparison of\ such methods is lacking. We organized a scientific challenge, in\ which developers could evaluate their method on a standardized\ multi-center/-scanner image dataset, giving an objective comparison:\ the WMH Segmentation Challenge (http://wmh.isi.uu.nl/).\ Sixty T1+FLAIR images from three MR scanners were released\ with manual WMH segmentations. A secret test set of 110\ images from five MR scanners was used for evaluation. Methods\ had to be containerized and submitted to the challenge organizers.Five evaluation metrics were used to rank the methods:\ (1) Dice Similarity Coefficient, (2) modified Hausdorff distance\ (95th percentile), (3) absolute percentage volume difference, (4)\ sensitivity for detecting individual lesions, and (5) F1-score for\ individual lesions. Additionally, methods were ranked on their\ inter-scanner robustness.\ Twenty participants submitted their method for evaluation.\ This paper provides a detailed analysis of the results. In brief,there is a cluster of four methods that rank significantly better\ than the other methods. There is one clear winner, which also\ has the best inter-scanner robustness.\ The challenge remains open for future submissions and provides\ a public platform for method evaluation.

}, keywords = {brain, Evaluation and performance, Magnetic resonance imaging (MRI), segmentation}, issn = {0278-0062}, doi = {10.1109/TMI.2019.2905770}, author = {Hugo Kuijf and Matthijs Biesbroek and Jeroen de Bresser and Rutger Heinen and Simon Andermatt and Mariana Bento and Matt Berseth and Mikhail Belyaev and Jorge Cardoso and Adri{\`a} Casamitjana and Louis Collins and Mahsa Dadar and Achileas Georgiou and Mohsen Ghafoorian and Dakai Jin and April Khademi and Jesse Knight and Hongwei Li and Xavier Llado and Miguel Luna and Qaiser Mahmood and Richard McKinley and Alireza Mehrtash and Sebastien Ourselin and Bo-yong Park and Hyunkin Park and Sang Hyun Park and Simon Pezold and Elodie Puybareau and Leticia Rittner and Carole Sudre and Sergi Valverde and Ver{\'o}nica Vilaplana and Rolan Wiest and Yongchao Xu and Ziyue Xu and Guodong Zeng and Jianguo Zhang and Guoyan Zheng and Christoper Chen and Wiesje van der Flier and Frederik Barkhof and Max Viergever and Geert Jan Biessels} } @phdthesis {dCasamitjana19, title = {Study of early stages of Alzheimer{\textquoteright}s disease using magnetic resonance imaging}, volume = {PhD}, year = {2019}, school = {Universitat Polit{\`e}cnica de Catalunya}, address = {Barcelona}, abstract = {

Alzheimer{\textquoteright}s disease (AD) is a neurodegenerative disorder that constitutes the most common dementia pathology. It represents a global epidemic that expands exponentially as the life expectancy increases with no yet useful treatment. Currently, it represents a huge social and economic burden for our societies and it is expected to tension public health infraestructures and finances in the near future.

AD is characterized by amyloid plaque deposition and neurofibrillary tangles measured by ex-vivo examination of the brain. Recent developments in fluid biomarkers and brain imaging allow in-vivo quantification of pathophysiological processes of amyloid deposition or tau tangles formation in the brain, providing the community with highly sensitive and specific in-vivo biomarkers for Alzheimer{\textquoteright}s disease diagnosis. Abnormal levels of these biomarkers are thought as the initiating event to a cascade of subsequent events that continue with synapse loss, cell death, memory impairment, functional dysfunction and cognitive decline. All these events constitute the Alzheimer{\textquoteright}s continuum which can be broadly split into two main parts: an initial long and silent preclinical stage characterized by abnormal AD biomarkers and cognition within the normal range that could last from 15 to 30 years and a posterior clinical stage where subjects develop dementia symptoms.

The etiology of AD is still poorly understood even though several risk factors are identified. Large observational studies can help the study of AD and its related biomarkers and risk factors. In this thesis we provide methodological tools for the analysis of Alzheimer{\textquoteright}s disease using magnetic resonance imaging (MRI). We focus on the study of subjects within the preclinial stage of AD by using statistical learning and pattern recognition frameworks to perform inferential statistics and develop predictive models.

The main outcomes of this thesis are three-fold: firstly, we develop an open-source toolbox for nonlinear neuroimage analysis in population studies. While nonlinear association between medical images and several factors is already known, standard neuroimaging softwares only provide linear statistical frameworks that limit the analyses. Secondly, we study the relationship between brain structure using MRI and the underlying Alzheimer{\textquoteright}s pathology along the disease continuum and at different stages. The close relationship between MRI and clinical symptoms has been widely studied but describing AD using biomarkers instead of clinical phenotypes allows us to study preclinical stages of AD. Finally, we present a framework to predict cognitively unimpaired and amyloid positive subjects using MR imaging and machine learning. We report the results in a cross-sectional study and in a longitudinal study that compares the volumetric rate-of-change between subjects with different amyloid status. We further test the proposed methodology as a part of the triaging process in clinical trials showing great potential benefits.

}, url = {http://hdl.handle.net/10803/668251}, author = {Adri{\`a} Casamitjana}, editor = {Ver{\'o}nica Vilaplana} } @mastersthesis {xCasals19, title = {Synthesis of acne images for data augmentation with generative adversarial networks}, year = {2019}, abstract = {

Generative Adversarial Networks (GANs) are deep learning architectures known for their usefulness on synthesizing new images. Conditioned image generation or the synthesis of super-resolution images are some of their main uses, but they are also helpful when tackling particular image classification and segmentation problems. The latter application is the motivation for the work presented in this document.

This work studies the synthesis of acne images for data augmentation, a procedure validated using said synthetic images to tackle an image classification problem.

The main challenge will be to work around the instability in the training of GANs. Therefore, different known solutions will be implemented in order to overcome this problem.

}, author = {Roger Casals}, editor = {Ver{\'o}nica Vilaplana} } @conference {cGene-Mola19, title = {Uso de redes neuronales convolucionales para la detecci{\'o}n remota de frutos con c{\'a}maras RGB-D}, booktitle = {Congreso Ib{\'e}rico de Agroingenier{\'\i}a}, year = {2019}, month = {09/2019}, publisher = { Universidad de Zaragoza (UZA)}, organization = { Universidad de Zaragoza (UZA)}, address = {Huesca}, abstract = {

La detecci{\'o}n remota de frutos ser{\'a} una herramienta indispensable para la gesti{\'o}n agron{\'o}mica optimizada y sostenible de las plantaciones frut{\'\i}colas del futuro, con aplicaciones en previsi{\'o}n de cosecha, robotizaci{\'o}n de la recolecci{\'o}n y elaboraci{\'o}n de mapas de producci{\'o}n. Este trabajo propone el uso de c{\'a}maras de profundidad RGB-D para la detecci{\'o}n y la posterior localizaci{\'o}n 3D de los frutos. El material utilizado para la adquisici{\'o}n de datos consiste en una plataforma terrestre autopropulsada equipada con dos sensores Kinect v2 de Microsoft y un sistema de posicionamiento RTK-GNSS. Con este equipo se escanearon 3 filas de manzanos Fuji de una explotaci{\'o}n comercial. El conjunto de datos adquiridos est{\'a} compuesto por 110 capturas que contienen un total de 12,838 manzanas Fuji. La detecci{\'o}n de frutos se realiz{\'o} mediante los datos RGB (im{\'a}genes de color proporcionadas por el sensor). Para ello, se implement{\'o} y se entren{\'o} la red neuronal convolucional de detecci{\'o}n de objetos Faster R-CNN, la cual est{\'a} compuesta por dos m{\'o}dulos: red de propuesta de regiones de inter{\'e}s y red de clasificaci{\'o}n. Ambos m{\'o}dulos comparten las primeras capas convolucionales siguiendo el modelo VGG-16 pre-entrenado con la base de datos ImageNet. Los resultados de test muestran un porcentaje de detecci{\'o}n del 91.4\% de los frutos con un 15.9\% de falsos positivos (F1-score = 0.876). La evaluaci{\'o}n cualitativa de las detecciones muestra que los falsos positivos corresponden a zonas de la imagen que presentan un patr{\'o}n muy similar a una manzana, donde, incluso a percepci{\'o}n del ojo humano, es dif{\'\i}cil de determinar si hay o no manzana. Por otro lado, las manzanas no detectadas corresponden a aquellas que estaban ocultas casi en su totalidad por otros {\'o}rganos vegetativos (hojas o ramas) o a manzanas cortadas por los m{\'a}rgenes de la imagen. De los resultados experimentales se concluye que el sensor Kinect v2 tiene un gran potencial para la detecci{\'o}n y localizaci{\'o}n 3D de frutos. La principal limitaci{\'o}n del sistema es que el rendimiento del sensor de profundidad se ve afectado en condiciones de alta iluminaci{\'o}n

}, keywords = {C{\'a}maras de profundidad, Detecci{\'o}n de frutos, Redes neuronales convolucionales, RGB-D, Rob{\'o}tica agr{\'\i}cola}, doi = {https://doi.org/10.26754/c_agroing.2019.com.3325}, author = {Gen{\'e}-Mola, Jordi and Ver{\'o}nica Vilaplana and Rosell-Polo, Joan R. and Morros, J.R. and Ruiz-Hidalgo, J. and Gregorio, Eduard} } @conference {cHerrera-Palacio, title = {Video Object Linguistic Grounding}, booktitle = {ACM Multimedia Workshop on Multimodal Understanding and Learning for Embodied Applications (MULEA)}, year = {2019}, month = {10/2019}, publisher = {ACM}, organization = {ACM}, address = {Nice, France}, abstract = {

The goal of this work is segmenting on a video sequence the objects\ which are mentioned in a linguistic description of the scene. We\ have adapted an existing deep neural network that achieves state of\ the art performance in semi-supervised video object segmentation,\ to add a linguistic branch that would generate an attention map\ over the video frames, making the segmentation of the objects\ temporally consistent along the sequence.

Video Object Linguistic Grounding from Universitat Polit{\`e}cnica de Catalunya

Xavier Giro-i-Nieto and Amanda Duarte in ACM Multimedia 2019

}, author = {Herrera-Palacio, Alba and Ventura, C. and Xavier Gir{\'o}-i-Nieto} } @conference {cXu, title = {Action Tube Extraction based 3D -CNN for RGB-D Action Recognition}, booktitle = {International Conference on Content-Based Multimedia Indexing CBMI 2018}, year = {2018}, month = {09/2018}, abstract = {

In this paper we propose a novel action tube extractor for RGB-D action recognition in trimmed videos. The action tube extractor takes as input a video and outputs an action

tube. The method consists of two parts: spatial tube extraction and temporal sampling. The first part is built upon MobileNet-SSD and its role is to define the spatial region where the action takes place. The second part is based on the structural similarity index (SSIM) and is designed to remove frames without obvious motion from the primary action tube. The final extracted action tube has two benefits: 1) a higher ratio of ROI (subjects of action) to background; 2) most frames contain obvious motion change. We propose to use a two-stream (RGB and Depth) I3D architecture as our 3D-CNN model. Our approach outperforms the state-of-the-art methods on the OA and NTU RGB-D datasets.

}, doi = {https://doi.org/10.1109/CBMI.2018.8516450}, author = {Zineng Xu and Ver{\'o}nica Vilaplana and Morros, J.R.} } @inbook {bTochon18, title = {Advances in utilization of hierarchical representations in remote sensing data analysis}, booktitle = {Reference Module in Earth Systems and Environmental Sciences}, volume = {2}, year = {2018}, pages = {77-107}, publisher = {Elsevier}, organization = {Elsevier}, issn = {978-0-12-409548-9}, author = {G. Tochon and Dalla Mura, M. and Veganzones, M.A. and Valero, S. and Salembier, P. and Chanussot, J.} } @mastersthesis {xArtigot18, title = {Automatic fruit classification using deep learning}, year = {2018}, abstract = {

To achieve greater efficiency at harvesting tasks, the mechanization of such task is unavoidable. Apart from the mechanical aspects, the harvesting systems needs software that can locate the fruit to be harvested.

The use of machine learning and deep learning techniques to achieve such software was studied in this thesis. The results showed that an accuracy similar to other studies is feasible with a limited number of training samples using deep learning techniques.

From this thesis we conclude that the mechanization of the harvesting labour is possible, at least from the software point of view, while the crop estimation application may need some more work before being feasible.

}, author = {Joaquim Mart{\'\i}nez Artigot}, editor = {Josep Ramon Morros and Ver{\'o}nica Vilaplana} } @mastersthesis {xRosello18, title = {Brain lesion segmentation using Convolutional Neuronal Networks}, year = {2018}, abstract = {

Convolutional neural networks (CNN) are powerful tools for learning representations from images. They are being used in a large range of applications, being the state-of-the art in many computer vision tasks. In this work, we study the brain tumor segmentation problem using CNNs and the publicly available BraTS dataset. One of the key factors for this task is which training scheme is used since it should deal with memory constraints and should alleviate the high-imbalance nature between healthy and lesion tissue in the brain.

Thus, the purpose of this project is to propose a comparison between several training schemes and extensively analyze and evaluate them in terms of the dice score. We evaluate densetraining against patch-sampling, and particularly, xed-rule against adaptive sampling scheme. Furthermore, variants and modications of the existing training schemes have been proposed in order to enhance their performance. Finally, several loss functions for each training scheme have been analyzed.

}, author = {Clara Bon{\'\i}n Rosell{\'o}}, editor = {Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana} } @conference {cSancheza, title = {Brain MRI Super-Resolution using Generative Adversarial Networks}, booktitle = {International Conference on Medical Imaging with Deep Learning}, year = {2018}, month = {07/2018}, address = {Amsterdam, The Netherlands}, author = {Irina S{\'a}nchez and Ver{\'o}nica Vilaplana} } @inbook {bCasamitjana18, title = {Cascaded V-Net Using ROI Masks for Brain Tumor Segmentation}, booktitle = {Brainlesion: Glioma, Multiple Sclerosis, Stroke and Traumatic Brain Injuries. BrainLes 2017}, volume = { 10670}, number = {Lecture Notes in Computer Science}, year = {2018}, pages = {381-391}, publisher = {Springer}, organization = {Springer}, edition = {Crimi A., Bakas S., Kuijf H., Menze B., Reyes M. (eds)}, address = {Cham}, abstract = {

In this work we approach the brain tumor segmentation problem with a cascade of two CNNs inspired in the V-Net architecture, reformulating residual connections and making use of ROI masks to constrain the networks to train only on relevant voxels. This architecture allows dense training on problems with highly skewed class distributions, such as brain tumor segmentation, by focusing training only on the vecinity of the tumor area. We report results on BraTS2017 Training and Validation sets.

}, isbn = {978-3-319-75238-9}, issn = {978-3-319-75237-2}, doi = {https://doi.org/10.1007/978-3-319-75238-9_33}, url = {https://link.springer.com/chapter/10.1007/978-3-319-75238-9_33}, author = {Adri{\`a} Casamitjana and Marcel Cat{\`a} and Irina S{\'a}nchez and Marc Combalia and Ver{\'o}nica Vilaplana} } @conference {cPetrone, title = {Characteristic Brain Volumetric Changes in the AD Preclinical Signature}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2018}, month = {07/2018}, address = {Chicago, USA}, abstract = {

In the last decade, magnetic resonance imaging has unveiled specific AD alterations at different stages of the AD pathophysiologic continuum that conform what has been established as the AD signature. To which extent MRI can detect structural changes at the preclinical asymptomatic stage of AD - the preclinical AD signature- is still an area open for exploration. Our work supports the idea that there are brain volumetric changes specific to preclinical AD subjects and defines the preclinical AD signature based on longitudinal data. While some regions show a pattern of atrophy that overlaps with the AD signature, other specific regions exhibit changes that are unique to this early asymptomatic AD stage.

}, author = {P. Petrone and Adri{\`a} Casamitjana and C. Falcon and M. Artigues and G. Operto and S. Skouras and R. Cacciaglia and J.L. Molinuevo and Ver{\'o}nica Vilaplana and J.D. Gispert} } @article {aPetrone18, title = {Characteristic Brain Volumetric Changes in the AD Preclinical Signature.}, journal = {Alzheimer{\textquoteright}s \& Dementia: The Journal of the Alzheimer{\textquoteright}s Association}, volume = {14}, year = {2018}, month = {07/2018}, pages = {P1235}, doi = {10.1016/j.jalz.2018.06.1737}, author = {P. Petrone and Adri{\`a} Casamitjana and C. Falcon and M. Artigues and G. Operto and S. Skouras and J.L. Molinuevo and Ver{\'o}nica Vilaplana and J.D. Gispert} } @mastersthesis {xPelegri18, title = {Clasificaci{\'o}n de im{\'a}genes histol{\'o}gicas mediante redes neuronales convolucionales}, year = {2018}, author = {Joel Bustos Pelegr{\'\i}}, editor = {Marc Combalia and Ver{\'o}nica Vilaplana} } @mastersthesis {xRos18, title = {Generative Adversarial Networks for Anomaly Detection in Images}, year = {2018}, abstract = {

Anomaly detection is used to identify abnormal observations that don{\textquoteright}t follow a normal pattern. In

this work, we use the power of Generative Adversarial Networks in sampling from image distributions

to perform anomaly detection with images and to identify local anomalous segments within this

images. Also, we explore potential application of this method to support pathological analysis of

biological tissues.

}, author = {Guillem Batiste}, editor = {Ver{\'o}nica Vilaplana} } @conference {cBakas19, title = {Identifying the best machine learning algorithms for brain tumor segmentation, progression assessment, and overall survival prediction in the BRATS challenge}, booktitle = {MICCAI - Multimodal Brain Tumor Segmentation Challenge}, year = {2018}, month = {12/2018}, abstract = {

Gliomas are the most common primary brain malignancies, with different degrees of aggressiveness, variable prognosis and various heterogeneous histologic sub-regions, i.e., peritumoral edematous/invaded tissue, necrotic core, active and non-enhancing core. This intrinsic heterogeneity is also portrayed in their radio-phenotype, as their sub-regions are depicted by varying intensity profiles disseminated across multi-parametric magnetic resonance imaging (mpMRI) scans, reflecting varying biological properties. Their heterogeneous shape, extent, and location are some of the factors that make these tumors difficult to resect, and in some cases inoperable. The amount of resected tumor is a factor also considered in longitudinal scans, when evaluating the apparent tumor for potential diagnosis of progression. Furthermore, there is mounting evidence that accurate segmentation of the various tumor sub-regions can offer the basis for quantitative image analysis towards prediction of patient overall survival. This study assesses the state-of-the-art machine learning (ML) methods used for brain tumor image analysis in mpMRI scans, during the last seven instances of the International Brain Tumor Segmentation (BraTS) challenge, i.e., 2012-2018. Specifically, we focus on i) evaluating segmentations of the various glioma sub-regions in pre-operative mpMRI scans, ii) assessing potential tumor progression by virtue of longitudinal growth of tumor sub-regions, beyond use of the RECIST/RANO criteria, and iii) predicting the overall survival from pre-operative mpMRI scans of patients that underwent gross total resection. Finally, we investigate the challenge of identifying the best ML algorithms for each of these tasks, considering that apart from being diverse on each instance of the challenge, the multi-institutional mpMRI BraTS dataset has also been a continuously evolving/growing dataset.

}, url = {https://arxiv.org/pdf/1811.02629.pdf}, author = {Spyridon Bakas and Mauricio Reyes and Andras Jakab and Stefan Bauer and Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and et. Al.} } @conference {cGorrizb, title = {Leishmaniasis Parasite Segmentation and Classification Using Deep Learning}, booktitle = {International Conference on Articulated Motion and Deformable Objects}, year = {2018}, address = {Palma, Spain}, abstract = {

Leishmaniasis is considered a neglected disease that causes thousands of deaths annually in some tropical and subtropical countries. There are various techniques to diagnose leishmaniasis of which manual microscopy is considered to be the gold standard. There is a need for the development of automatic techniques that are able to detect parasites in a robust and unsupervised manner. In this paper we present a procedure for automatizing the detection process based on a deep learning approach. We train a U-net model that successfully segments leismania parasites and classifies them into promastigotes, amastigotes and adhered parasites.

}, author = {G{\'o}rriz, Marc and Albert Aparicio and Berta Ravent{\'o}s and Daniel L{\'o}pez-Codina and Ver{\'o}nica Vilaplana and Elisa Sayrol} } @inbook {bGorriz18, title = {Leishmaniasis Parasite Segmentation and Classification Using Deep Learning}, booktitle = { Articulated Motion and Deformable Objects}, volume = {10945}, number = {Lecture Notes in Computer Science}, year = {2018}, pages = {53-62}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Leishmaniasis is considered a neglected disease that causes thousands of deaths annually in some tropical and subtropical countries. There are various techniques to diagnose leishmaniasis of which manual microscopy is considered to be the gold standard. There is a need for the development of automatic techniques that are able to detect parasites in a robust and unsupervised manner. In this paper we present a procedure for automatizing the detection process based on a deep learning approach. We train a U-net model that successfully segments leismania parasites and classifies them into promastigotes, amastigotes and adhered parasites.

}, issn = {978-3-319-94544-6}, doi = {10.1007/978-3-319-94544-6}, author = {G{\'o}rriz, Marc and Albert Aparicio and Berta Ravent{\'o}s and Ver{\'o}nica Vilaplana and Elisa Sayrol and Daniel L{\'o}pez-Codina} } @conference {cCombaliaa, title = {Monte-Carlo Sampling applied to Multiple Instance Learning for Histological Image Classification}, booktitle = {Workshop on Deep Learning in Medical Image Analysis, MICCAI}, year = {2018}, month = {2018}, address = {Granada, Spain}, abstract = {

We propose a patch sampling strategy based on a sequential Monte-Carlo method for high resolution image classification in the context of Multiple Instance Learning. When compared with grid sampling and uniform sampling techniques, it achieves higher generalization performance. We validate the strategy on two artificial datasets and two histological datasets for breast cancer and sun exposure classification.\ 

}, author = {Marc Combalia and Ver{\'o}nica Vilaplana} } @inbook {bCombalia18, title = {Monte-Carlo Sampling Applied to Multiple Instance Learning for Histological Image Classification}, booktitle = {Deep Learning in Medical Image Analysis and Multimodal Learning for Clinical Decision Support}, number = {11045}, year = {2018}, pages = {274-281}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

We propose a patch sampling strategy based on a sequential Monte-Carlo method for high resolution image classification in the context of Multiple Instance Learning. When compared with grid sampling and uniform sampling techniques, it achieves higher generalization performance. We validate the strategy on two artificial datasets and two histological datasets for breast cancer and sun exposure classification.

}, isbn = {978-3-030-00889-5}, issn = {10.1007/978-3-030-00889-5}, doi = {10.1007/978-3-030-00889-5}, author = {Marc Combalia and Ver{\'o}nica Vilaplana} } @conference {cCombalia, title = {Monte-Carlo Sampling applied to Multiple Instance Learning for Whole Slide Image Classification}, booktitle = {International Conference on Medical Imaging with Deep Learning}, year = {2018}, month = {07/2018}, address = {Amsterdam, The Netherlands}, author = {Marc Combalia and Ver{\'o}nica Vilaplana} } @article {aCasamitjana, title = {MRI-Based Screening of Preclinical Alzheimer{\textquoteright}s Disease for Prevention Clinical Trials}, journal = {Journal of Alzheimer{\textquoteright}s Disease}, volume = {64}, year = {2018}, month = {07/2018}, chapter = {1099}, abstract = {

The identification of healthy individuals harboring amyloid pathology constitutes one important challenge for secondary prevention clinical trials in Alzheimer{\textquoteright}s disease (AD). Consequently, noninvasive and cost-efficient techniques to detect preclinical AD constitute an unmet need of critical importance. In this manuscript, we apply machine learning to structural MRI (T1 and DTI) of 96 cognitively normal subjects to identify amyloid-positive ones. Models were trained on public ADNI data and validated on an independent local cohort. Used for subject classification in a simulated clinical trial setting, the proposed method is able to save 60\% unnecessary CSF/PET tests and to reduce 47\% of the cost of recruitment when used in a simulated clinical trial setting. This recruitment strategy capitalizes on already acquired MRIs to reduce the overall amount of invasive PET/CSF tests in prevention trials, demonstrating a potential value as a tool for AD screening. This protocol could foster the development of secondary prevention strategies for AD.

}, author = {Adri{\`a} Casamitjana and Paula Petrone and Alan Tucholka and Carles Falcon and Stavros Skouras and Jose Luis Molinuevo and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @conference {cShou, title = {Online Action Detection in Untrimmed, Streaming Videos}, booktitle = {European Conference on Computer Vision (ECCV)}, year = {2018}, month = {02/2018}, address = {Munich, German}, abstract = {

}, url = {https://arxiv.org/abs/1802.06822}, author = {Shou, Zheng and Pan, Junting and Chan, Johnatan and Miyazawa, Kazuyuki and Mansour, Hassan and Vetro, Anthony and Xavier Gir{\'o}-i-Nieto and Chang, Shih-Fu} } @mastersthesis {xCanaves18, title = {Prevention of Alzheimer{\textquoteright}s Disease: a contribution from MRI and machine learning}, year = {2018}, abstract = {

Alzheimer{\textquoteright}s disease (AD) is a neurodegenerative disease and the leading cause of dementia (50-70\% of cases). Despite worldwide efforts, there is no progress in developing a cure for AD and dementia. Machine learning, hand in hand with magnetic resonance imaging (MRI), come to the aid of disease diagnostics. In the scope of AD, many efforts have been dedicated to the automated detection of mild-cognitive impairment and dementia. In our research, instead we focus on the prediction of AD in its preclinical stage using machine learning classification. Another key innovation is that we will work with a longitudinal pipeline. In addition to classification, the project focuses on detecting the most relevant imaging voxels for classification, that is, to help us locate where AD-specific structural brain changes occur. We have improved classification performance i n comparison with results obtained with cross-sectional datasets in previous studies and we have identified possible regions of interest based on feature scores obtained from feature selection.

}, author = {Miguel Artigues C{\`a}naves}, editor = {Paula Petrone and Ver{\'o}nica Vilaplana} } @conference {cCasamitjanab, title = {Projection to Latent Spaces Disentangles Specific Cerebral Morphometric Patterns Associated to Aging and Preclinical AD}, booktitle = {Alzheimer{\textquoteright}s Association International Conference}, year = {2018}, month = {07/2018}, address = {Chicago, USA}, abstract = {

Partial Least Squares (PLS) is a mathematical technique that relates two sets of observable variables by means of a few latent explanatory factors. The aim of this study is to use PLS to discover the associations between CSF biomarkers and structural brain imaging in preclinical AD and to disentangle their specific contribution from confounding demographic factors.PLS is able to disentangle the cerebral morphometric patterns associated to preclinical AD stages from other demographic factors. Results with both cortical thickness and volumetric data present significant overlap, thus showing the robustness of this approach. Interestingly, volumetric data showed more significant correlations with CSF Abeta than cortical thickness.

}, author = {Adri{\`a} Casamitjana and P. Petrone and M. Artigues and J.L. Molinuevo and J.D. Gispert and Ver{\'o}nica Vilaplana} } @article {aCasamitjana18, title = { Projection to Latent Spaces Disentangles Specific Cerebral Morphometric Patterns Associated to Aging and Preclinical AD}, journal = {Alzheimer{\textquoteright}s \& Dementia: The Journal of the Alzheimer{\textquoteright}s Association }, volume = {14}, year = {2018}, month = {07/2018}, pages = {P869-P870}, doi = {10.1016/j.jalz.2018.06.1111}, author = {Adri{\`a} Casamitjana and P. Petrone and M. Artigues and J.L. Molinuevo and J.D. Gispert and Ver{\'o}nica Vilaplana} } @mastersthesis {xGullon18, title = {Retinal lesions segmentation using CNNs and adversarial training}, year = {2018}, abstract = {

Convolutional Neural Networks (CNNs) are frequently used to tackle image classification and segmentation problems due to its recently proven successful results. In particular, in medical domain, it is more and more common to see automated techniques to help doctors in their diagnosis. In this work, we study the retinal lesions segmentation problem using CNNs on the Indian Diabetic Retinopathy Image Dataset (IDRiD). Additionally, the idea of adversarial training used by Generative Adversarial Networks (GANs) will be also added to the previous CNN to improve its results, making segmentation maps more accurate and realistic. A comparison between these two architectures will be made. One of the main challenges we will be facing is the high-imbalance between lesions and healthy parts of the retina and the fact that some lesion classes are very scattered in small fractions. Thus, different loss functions, optimizers and training schemes will be studied and evaluated to see which one best addresses our problem.

}, author = {Nat{\`a}lia Gull{\'o}n}, editor = {Ver{\'o}nica Vilaplana} } @inbook {bCasamitjana18a, title = {Shared Latent Structures Between Imaging Features and Biomarkers in Early Stages of Alzheimer{\textquoteright}s Disease}, booktitle = {PRedictive Intelligence in MEdicine}, volume = {11121}, year = {2018}, pages = {60-67}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

In this work, we identify meaningful latent patterns in MR images for patients across the Alzheimer{\textquoteright}s disease (AD) continuum. For this purpose, we apply Projection to Latent Structures (PLS) method using cerebrospinal fluid (CSF) biomarkers (t-tau, p-tau, amyloid-beta) and age as response variables and imaging features as explanatory variables. Freesurfer pipeline is used to compute MRI surface and volumetric features resulting in 68 cortical ROIs and 84 cortical and subcortical ROIs, respectively. The main assumption of this work is that there are two main underlying processes governing brain morphology along the AD continuum: brain aging and dementia. We use two different and orthogonal PLS models to describe each process: PLS-aging and PLS-dementia. To define PLS-aging model we use normal aging subjects and age as predictor and response variables, respectively, while for PLS-dementia we only use demented subjects and biomarkers as response variables.

}, issn = {978-3-030-00320-3}, doi = {10.1007/978-3-030-00320-3}, author = {Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and Paula Petrone and Jose Luis Molinuevo and Juan D. Gispert} } @conference {cCasamitjanac, title = {Shared latent structures between imaging features and biomarkers in early stages of Alzheimer{\textquoteright}s disease}, booktitle = {Workshop on Predictive Intelligence in Medicine (PRIME), MICCAI}, year = {2018}, month = {2018}, address = {Granada, Spain}, abstract = {

In this work, we identify meaningful latent patterns in MR images for patients across the Alzheimer{\textquoteright}s disease (AD) continuum. For this purpose, we apply Projection to Latent Structures (PLS) method using cerebrospinal fluid (CSF) biomarkers (t-tau, p-tau, amyloid-beta) and age as response variables and imaging features as explanatory variables. Freesurfer pipeline is used to compute MRI surface and volumetric features\  \ resulting in 68 cortical ROIs and 84 cortical and subcortical ROIs, respectively. The main assumption of this work is that there are two main underlying processes governing brain morphology along the AD continuum: brain aging and dementia. We use two different and orthogonal PLS models to describe each process: PLS-aging and PLS-dementia. To define PLS-aging model we use normal aging subjects and age as predictor and response variables, respectively, while for PLS-dementia we only use demented subjects and biomarkers as response variables.\ 

}, author = {Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and Paula Petrone and Jose Luis Molinuevo and Juan D. Gispert} } @conference {cFernandezb, title = {What is going on in the world? A display platform for media understanding}, booktitle = {IEEE Multimedia Information Processing and Retrieval (MIPR) Conference}, year = {2018}, month = {04/2018}, publisher = {IEEE}, organization = {IEEE}, address = {Miami, FL (USA)}, abstract = {

News broadcasters and on-line publishers daily generate a large amount of articles and videos describing events currently happening in the world. In this, work we present a system that automatically indexes videos from a library and links them to stories developing in the news. The user interface displays in an intuitive manner the links between\  videos and stories and allows navigation through related content by using associated tags. This interface is a powerful industrial tool for publishers to index, retrieve and visualize their video content. It helps them identify which topics require more attention or retrieve related content that{\textquoteright}s already been published about the stories.

}, doi = {https://doi.org/10.1109/MIPR.2018.00045}, url = {https://www.youtube.com/watch?v=eaXcB2X-5xY}, author = {Fern{\`a}ndez, D{\`e}lia and David Varas and Bou, Elisenda and Xavier Gir{\'o}-i-Nieto} } @inbook {bCasamitjana, title = {3D Convolutional Neural Networks for Brain Tumor Segmentation: a comparison of multi-resolution architectures}, booktitle = {Lecture Notes in Computer Vision}, volume = {Brainlesion: Glioma, Multiple Sclerosis, Stroke and Traumatic Brain Injuries}, year = {2017}, pages = {150-161}, publisher = {Springer}, organization = {Springer}, issn = {978-3-319-55524-9}, author = {Adri{\`a} Casamitjana and Santi Puch and Asier Aduriz and Ver{\'o}nica Vilaplana} } @article {aMaceiraa, title = {3D hierarchical optimization for multi-view depth map coding}, journal = {Multimedia Tools and Applications}, year = {2017}, month = {12/2017}, abstract = {

Full version available at:\ http://rdcu.be/zHtU

Depth data has a widespread use since the popularity of high resolution 3D sensors. In multi-view sequences, depth information is used to supplement the color data of each view. This article proposes a joint encoding of multiple depth maps with a unique representation. Color and depth images of each view are segmented independently and combined in an optimal Rate-Distortion fashion. The resulting partitions are projected to a reference view where a coherent hierarchy forthe multiple views is built. A Rate-Distortion optimization is applied to obtain the final segmentation choosing nodes of the hierarchy. The consistent segmentation is used to robustly encode depth maps of multiple views obtaining competitive results with HEVC coding standards.

}, keywords = {3D representation, Depth coding, Multiview coding, segmentation based coding}, doi = {10.1007/s11042-017-5409-z}, url = {http://rdcu.be/zHtU}, author = {Maceira, M. and David Varas and Morros, J.R. and Ruiz-Hidalgo, J. and Marqu{\'e}s, F.} } @conference {cSanchez, title = {3D Medical Image Synthesis using Generative Adversarial Networks}, booktitle = {ACM Europe Celebration of Women in Computing, womENcourage 2017, Barcelona, Spain}, year = {2017}, month = {09/2017}, author = {Irina S{\'a}nchez and Ver{\'o}nica Vilaplana} } @conference {cCasamitjanaa, title = {Augmented V-Net for infant brain segmentation}, booktitle = {MICCAI Grand Challenge on 6-month Infant Brain MRI Segmentation, MICCAI 2017}, year = {2017}, month = {09/2017}, author = {Adri{\`a} Casamitjana and Irina S{\'a}nchez and Marc Combalia and Ver{\'o}nica Vilaplana} } @conference {cCasamitjana, title = {Augmented V-Net for White Matter Hyperintensities segmentation}, booktitle = {WMH Segmentation Challenge, Brain-lesion Workshop, MICCAI 2017 }, year = {2017}, month = {09/2017}, author = {Adri{\`a} Casamitjana and Irina S{\'a}nchez and Marc Combalia and Ver{\'o}nica Vilaplana} } @conference {cvan Sabben17, title = {Collaborative voting of 3D features for robust gesture estimation}, booktitle = {International Conference on Acoustics, Speech and Signal Processing}, year = {2017}, month = {03/2017}, address = {New Orleans, USA}, abstract = {

Human body analysis raises special interest because it enables a wide range of interactive applications. In this paper we present a gesture estimator that discriminates body poses in depth images. A novel collaborative method is proposed to learn 3D features of the human body and, later, to estimate specific gestures. The collaborative estimation framework is inspired by decision forests, where each selected point (anchor point) contributes to the estimation by casting votes. The main idea is to detect a body part by accumulating the inference of other trained body parts. The collaborative voting encodes the global context of human pose, while 3D features represent local appearance. Body parts contributing to the detection are interpreted as a voting process. Experimental results for different 3D features prove the validity of the proposed algorithm.

}, author = {van Sabben, D. and Ruiz-Hidalgo, J. and Suau, X. and Casas, J.} } @conference {cBellvera, title = {Detection-aided liver lesion segmentation using deep learning}, booktitle = {ML4H: Machine Learning for Health Workshop at NIPS 2017}, year = {2017}, month = {11/2017}, abstract = {

A fully automatic technique for segmenting the liver and localizing its unhealthy tissues is a convenient tool in order to diagnose hepatic diseases and assess the response to the according treatments. In this work we propose a method to segment the liver and its lesions from Computed Tomography (CT) scans using Convolutional Neural Networks (CNNs), that have proven good results in a variety of computer vision tasks, including medical imaging. The network that segments the lesions consists of a cascaded architecture, which first focuses on the region of the liver in order to segment the lesions on it. Moreover, we train a detector to localize the lesions, and mask the results of the segmentation network with the positive detections. The segmentation architecture is based on DRIU, a Fully Convolutional Network (FCN) with side outputs that work on feature maps of different resolutions, to finally\  benefit from the multi-scale information learned by different stages of the network. The main contribution of this work is the use of a detector to localize the lesions, which we show to be beneficial to remove false positives triggered by the segmentation network.

Detection-aided liver lesion segmentation using deep learning from Xavier Giro-i-Nieto
}, author = {M{\'\i}riam Bellver and Kevis-Kokitsi Maninis and Jordi Pont-Tuset and Jordi Torres and Xavier Gir{\'o}-i-Nieto and Luc van Gool} } @mastersthesis {xBellvera, title = {Detection-aided medical image segmentation using deep learning}, year = {2017}, abstract = {

Program:\ Master{\textquoteright}s Degree in Telecommunications Engineering

Grade: A with honours (10.0/10.0)

A fully automatic technique for segmenting the liver and localizing its unhealthy tissues is a convenient tool in order to diagnose hepatic diseases and also to assess the response to the according treatments. In this thesis we propose a method to segment the liver and its lesions from Computed Tomography (CT) scans, as well as other anatomical structures and organs of the human body. We have used Convolutional Neural Networks (CNNs), that have proven good results in a variety of tasks, including medical imaging. The network to segment the lesions consists of a cascaded architecture, which first focuses on the liver region in order to segment the lesion. Moreover, we train a detector to localize the lesions and just keep those pixels from the output of the segmentation network where a lesion is detected. The segmentation architecture is based on DRIU [24], a Fully Convolutional Network (FCN) with side outputs that work at feature maps of different resolutions, to finally benefit from the multi-scale information learned by different stages of the network. Our pipeline is 2.5D, as the input of the network is a stack of consecutive slices of the CT scans. We also study different methods to benefit from the liver segmentation in order to delineate the lesion. The main focus of this work is to use the detector to localize the lesions, as we demonstrate that it helps to remove false positives triggered by the segmentation network. The benefits of using a detector on top of the segmentation is that the detector acquires a more global insight of the healthiness of a liver tissue compared to the segmentation network, whose final output is pixel-wise and is not forced to take a global decision over a whole liver patch. We show experiments with the LiTS dataset for the lesion and liver segmentation. In order to prove the generality of the segmentation network, we also segment several anatomical structures from the Visceral dataset.

Detection-aided liver lesion segmentation using deep learning from Xavier Giro-i-Nieto
}, author = {M{\'\i}riam Bellver}, editor = {Kevis-Kokitsi Maninis and Jordi Pont-Tuset and Luc van Gool and Xavier Gir{\'o}-i-Nieto and Jordi Torres} } @mastersthesis {xCastello17, title = {Extracci{\'o}n de cr{\'a}neo en im{\'a}genes de resonancia magn{\'e}tica del cerebro utilizando una red neuronal convolucional 3D}, year = {2017}, author = {David Rodr{\'\i}guez Castell{\'o}}, editor = {Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana} } @article {aPetrone17, title = {Magnetic Resonance Imaging as a valuable tool for Alzheimer{\textquoteright}s disease screening}, journal = {Alzheimer{\textquoteright}s \& Dementia: The Journal of the Alzheimer{\textquoteright}s Association}, volume = {13}, year = {2017}, month = {07/2017}, pages = {P1245}, doi = {10.1016/j.jalz.2017.07.457}, url = {https://doi.org/10.1016/j.jalz.2017.07.457}, author = {P. Petrone and Ver{\'o}nica Vilaplana and Adri{\`a} Casamitjana and D. Sanchez-Escobedo and A. Tucholka and R. Cacciaglia and G. Operto and S. Skouras and C. Falcon and J.L. Molinuevo and J.D. Gispert} } @conference {cPetrone17, title = {Magnetic Resonance Imaging as a valuable tool for Alzheimer{\textquoteright}s disease screening}, booktitle = {Alzheimer{\textquoteright}s Association International Conference, London, 2017}, year = {2017}, month = {07/2017}, author = {P. Petrone and Ver{\'o}nica Vilaplana and Adri{\`a} Casamitjana and A. Tucholka and C. Falcon and R. Cacciaglia and G. Operto and S. Skouras and J.L. Molinuevo and J.D. Gispert} } @conference {cCata, title = {Masked V-Net: an approach to brain tumor segmentation}, booktitle = {Multimodal Brain Tumor Segmentation Benchmark, Brain-lesion Workshop, MICCAI 2017 }, year = {2017}, month = {09/2017}, author = {Marcel Cat{\`a} and Adri{\`a} Casamitjana and Irina S{\'a}nchez and Marc Combalia and Ver{\'o}nica Vilaplana} } @conference {cFernandeza, title = {ViTS: Video Tagging System from Massive Web Multimedia Collections}, booktitle = {ICCV 2017 Workshop on Web-scale Vision and Social Media }, year = {2017}, month = {10/2017}, address = {Venice, Italy}, abstract = {

The popularization of multimedia content on the Web has arised the need to automatically understand, index and retrieve it. In this paper we present ViTS, an automatic Video Tagging System which learns from videos, their web context and comments shared on social networks. ViTS analyses massive multimedia collections by Internet crawling, and maintains a knowledge base that updates in real time with no need of human supervision. As a result, each video is indexed with a rich set of labels and linked with other related contents. ViTS is an industrial product under exploitation with a vocabulary of over 2.5M concepts, capable of indexing more than 150k videos per month. We compare the quality and completeness of our tags with respect to the ones in the YouTube-8M dataset, and we show how ViTS enhances the semantic annotation of the videos with a larger number of labels (10.04 tags/video), with an accuracy of 80,87\%.

}, author = {Fern{\`a}ndez, D{\`e}lia and David Varas and Espadaler, Joan and Ferreira, Jordi and Woodward, Alejandro and Rodr{\'\i}guez, David and Xavier Gir{\'o}-i-Nieto and Riveiro, Juan Carlos and Bou, Elisenda} } @conference {cCasamitjana16, title = {3D Convolutional Neural Networks for Brain Tumor Segmentation}, booktitle = {MICCAI 2016 - Brain Lesion Workshop (BrainLes), Multimodal Brain Tumor Segmentation Challenge (BRATS)}, year = {2016}, month = {11/2016}, author = {Adri{\`a} Casamitjana and Santi Puch and Asier Aduriz and Elisa Sayrol and Ver{\'o}nica Vilaplana} } @mastersthesis {xAduriz16, title = {Analysis of the dynamics of gray matter reduction in Alzheimer{\textquoteright}s Disease}, year = {2016}, abstract = {

Advisor: Ver{\'o}nica Vilaplana

Studies: Bachelor degree in Science and Telecommunication Technologies Engineering at\ Telecom BCN-ETSETB\ from the Technical University of Catalonia (UPC)

This project attempts to study the cerebral atrophy patterns in gray matter across the
di erent stages of the Alzheimer{\textquoteright}s Disease (AD), or more speci cally, along the entire AD
continuum, in a voxelwise approach. To this end, we propose and implement an extensible
toolbox that allows to t di erent models to the data, hence de ning a curve for each voxel
that shows the evolution of the gray matter volume in the respective region as compared
to the progression of the disease. The toolbox also includes several evaluation methods
to estimate how closely the proposed model ts the data for each particular voxel. The
resulting values, namely tting-scores, serve as a base to achieve two di erent goals: a)
to identify the regions within the brain that are (most) likely to follow the curve-shape
speci ed in a given model, and b) to depict the model that best describes the behavior of
the gray matter volume in each voxel from a xed set of models.

}, author = {Asier Aduriz}, editor = {Ver{\'o}nica Vilaplana} } @mastersthesis {xCata16, title = {Feature Selection Methods for Predicting Pre-Clinical Stage in Alzheimer{\textquoteright}s Disease}, year = {2016}, abstract = {

Advisors: Ver{\'o}nica Vilaplana, Adri{\`a} Casamitjana

Studies: Bachelor degree in Science and Telecommunication Technologies Engineering at\ Telecom BCN-ETSETB\ from the Technical University of Catalonia (UPC)

Alzheimer{\textquoteright}s disease is still an incurable disease. Nevertheless, some of its biomarkers suffer changes in the early stages of the disease, long before clinical symptoms appear. In order to determine how biomarkers obtained from magnetic resonance (MRI) techniques affect the disease{\textquoteright}s evolution, machine learning techniques have been used to design and implement a classification system so as to predict the stages in which several patients belong. One of the main objectives of this project is reducing the number of data to manage, since MRI provide a large volume of data for each patient. As a result, we will focus on the stage of reduction and extraction of characteristics of the classifier which may be relevant for the mentioned problem. We will carry out an exhaustive analysis of different methods of selection of features to apply to biomedical data related to Alzheimer{\textquoteright}s disease. Results obtained will also be applicable to other fields. Finally, we will assess these methods with a multimodal data base provided by the collaboration agreement with Pasqual Maragall Foundation (FPM).

}, author = {Marcel Cat{\`a}}, editor = {Ver{\'o}nica Vilaplana and Adri{\`a} Casamitjana} } @mastersthesis {xSantamarta16, title = {Machine learning for recommendation systems in job postings selection}, year = {2016}, abstract = {

This project is the result of the study, implementation and combination of several recommender systems technics. Moreover, the project try to submit a solution for a challenge on job recommender system. Thus, it has been realized a study of the available technics on recommender systems. After that, it has been analyzed the information provided by organizers, in order to design the most accurate system. The design and the implementation of recommender systems models has been the next step on the project. Finally, the analysis and discussion of the results obtained has been the final step of the project. This step provides the best recommender system designed.

}, author = {Victor Marcos Santamarta}, editor = {Vidal, J. and Ver{\'o}nica Vilaplana} } @mastersthesis {xPuch16, title = {Nonlinear analysis toolbox for neurodegenerative diseases and aging}, year = {2016}, abstract = {

Advisor: Ver{\'o}nica Vilaplana

Studies: Bachelor degree in Science and Telecommunication Technologies Engineering at\ Telecom BCN-ETSETB\ from the Technical University of Catalonia (UPC)

Neurodegenerative diseases impose substantial public health burdens on populations
throughout the world. Alzheimer{\textquoteright}s disease is among the major neurodegenerative diseases,
and its causes and treatment are still unknown. Researchers around the world are conducting
large data-driven studies in order to unveil the causes and biological mechanisms of such
diseases, and for that reason automatic tools that allow to uncover statistically signi cant
ndings are needed.
To address this problem we present in this thesis a software toolbox that provides the
tools to analyze the linear and nonlinear dynamics of gray-matter and study the statistical
signi cance of such dynamics at the voxel level. The toolbox features various tting methods
and t evaluation metrics, an automatic hyperparameters look-up algorithm and several
visualization and comparison tools.
All the features provided in this toolbox were tested in two real problems provided by
the Pasqual Maragall Foundation, and it yielded results that were validated by the ndings
in the original studies.

}, author = {Santi Puch}, editor = {Ver{\'o}nica Vilaplana} } @phdthesis {dVaras16, title = {Region-based Particle Filter Leveraged with a Hierarchical Co-clustering}, year = {2016}, month = {11/2016}, school = {UPC}, type = {PhD}, address = {Barcelona}, abstract = {

In this thesis, we exploit the hierarchical information associated with images to tackle two fundamental problems of computer vision: video object segmentation and video segmentation.

In the first part of the thesis, we present a video object segmentation approach that extends the well known particle filter algorithm to a region based image representation. Image partition is considered part of the particle filter measurement, which enriches the available information and leads to a reformulation of the particle filter theory. We define particles as unions of regions in the current image partition and their propagation is computed through a single optimization process. During this propagation, the prediction step is performed using a co-clustering between the previous image object partition and a partition of the current one, which allows us to tackle the evolution of non-rigid structures.

The second part of the thesis is devoted to the exploration of a co-clustering technique for video segmentation. This technique, given a collection of images and their associated hierarchies, clusters nodes from these hierarchies to obtain a coherent multiresolution representation of the image collection. We formalize the co-clustering as a Quadratic Semi-Assignment Problem and solve it with a linear programming relaxation approach that makes e ffective use of information from hierarchies. Initially, we address the problem of generating an optimal, coherent partition per image and, afterwards, we extend this method to a multiresolution framework. Finally, we particularize this framework to an iterative multiresolution video segmentation algorithm in sequences with small variations.

Finally, in the last part of the thesis we validate the presented techniques for object and video segmentation using the proposed algorithms as tools to tackle problems in a context for which they were not initially thought.

}, author = {David Varas}, editor = {Marqu{\'e}s, F.} } @phdthesis {dVentura16, title = {Visual Object Analysis using Regions and Local Features}, year = {2016}, abstract = {

Thesis submission: 10-06-2016

Defense date:\ 08-07-2016

Grade: Excel{\textperiodcentered}lent Cum Laude \& International Mention

The fi rst part of this dissertation focuses on an analysis of the spatial context in semantic image segmentation. First, we review how spatial context has been tackled in the literature by local features and spatial aggregation techniques. From a discussion about whether the context is bene ficial or not for object recognition, we extend a Figure-Border-Ground segmentation for local feature aggregation with ground truth annotations to a more realistic scenario where object proposals techniques are used instead. Whereas the Figure and Ground regions represent the object and the surround respectively, the Border is a region around the object contour, which is found to be the region with the richest contextual information for object recognition. Furthermore, we propose a new contour-based spatial aggregation technique of the local features within the object region by a division of the region into four subregions. Both contributions have been tested on a semantic segmentation benchmark with a combination of free and non-free context local\ features that allows the models automatically learn whether the context is benefi cial or not for each semantic category.

The second part of this dissertation addresses the semantic segmentation for a set of closely-related images from an uncalibrated multiview scenario. State-of-the-art semantic segmentation algorithms fail on correctly segmenting the objects from some viewpoints when the techniques are independently applied to each viewpoint image. The lack of large annotations available for multiview segmentation do not allow to obtain a proper model that is robust to viewpoint changes. In this second part, we exploit the spatial correlation that exists between the di erent viewpoints images to obtain a more robust semantic segmentation. First, we review the state-of-the-art co-clustering, co-segmentation and video segmentation techniques that aim to segment the set of images in a generic way, i.e. without considering semantics. Then, a new architecture that considers motion information and provides a multiresolution segmentation is proposed for the co-clustering framework and outperforms state-of-the-art techniques for generic multiview segmentation. Finally,\ the proposed multiview segmentation is combined with the semantic segmentation results giving a method for automatic resolution selection and a coherent semantic multiview segmentation.

Visual Object Analysis using Regions and Local Features from Xavier Giro

}, url = {http://hdl.handle.net/10803/398407}, author = {Ventura, C.}, editor = {Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cPuch, title = {Voxelwise nonlinear regression toolbox for neuroimage analysis: Application to aging and neurodegenerative disease modeling}, booktitle = {NIPS 2016 Workshop on Machine Learning for Health}, year = {2016}, month = {12/2016}, author = {Santi Puch and Asier Aduriz and Adri{\`a} Casamitjana and Ver{\'o}nica Vilaplana and Juan D. Gispert} } @mastersthesis {xPanizo15, title = {Classification techniques for Alzheimer{\textquoteright}s disease early diagnosis}, year = {2015}, abstract = {

Advisor: Ver{\'o}nica Vilaplana

Studies: Telecommunication Engineering at\ Telecom BCN-ETSETB\ from the Technical University of Catalonia (UPC)

Alzheimer{\textquoteright}s disease currently affects more than 36 million people in the world. A patient{\textquoteright}s brain suffers changes during the earliest stages of the disease and long before showing any clinical symptoms. For that reason, researchers focus their efforts towards defining which changes occur and where do they take place, with the goal of detecting indicators to predict the development of the disease. Specifically, the entity Fundaci{\'o}n Pascual Maragall para la investigaci{\'o}n contra el Alzheimer studies the processes of the brain all along the disease{\textquoteright}s stages using images obtained through different MRI techniques. The huge volume of data generated in this kind of investigation is a big obstacle to carry out analysis and extracting conclusions. The aim of this thesis is making this process easier by using data mining techniques. The goal is to develop a basic classification system to distinguish in which stage of the disease a patient is in, using data extracted from cerebral images. This system must form the basis for a future data mining system that satisfies the necessities of the Fundaci{\'o}n Pascual Maragall researchers. In addition to the classification system, this project focuses on distinguishing which is the most relevant data in the classification and on optimizing the classification in the pre-clinical stage of the disease.

}, author = {Eva Panizo}, editor = {Ver{\'o}nica Vilaplana} } @mastersthesis {xVela15, title = {Combinar im{\'a}genes y h{\'a}bitos musicales para mejorar los sistemas de recomendaci{\'o}n de m{\'u}sica}, year = {2015}, url = {http://hdl.handle.net/2099.1/26236}, author = {Enrique Sa{\~n}oso Vela}, editor = {Ver{\'o}nica Vilaplana and Josep Ramon Morros} } @mastersthesis {xAlonso15, title = {Detecci{\'o} de Text utilitzant Xarxes Neuronals Convolucionals }, year = {2015}, abstract = {

Text detection in images is a challenging problem that has received a significant amount of attention. The inclusion of machine learning allows building accurate classifiers. The goal of this work is to detect text in images. In order to achieve this goal we analyze the Convolutional Neural Network (CNN). We use an implemented CNN to detect areas where there may be text. Then we analyze and filter this areas so we can obtain the detected text.\ 

}, author = {Antea Herrera Alonso}, editor = {Ver{\'o}nica Vilaplana} } @conference {cTacchini, title = {Do you have a Pop face? Here is a Pop song. Using profile pictures to mitigate the cold-start problem in Music Recommender Systems}, booktitle = {9th ACM Conference on Recommender Systems}, year = {2015}, month = {09/2015}, author = {Tacchini, E. and Morros, J.R. and Ver{\'o}nica Vilaplana and Sa{\~n}oso, E.} } @mastersthesis {xBellver-Bueno, title = {Efficient Exploration of Region Hierarchies for Semantic Segmentation}, year = {2015}, abstract = {

Advisors: Carles Ventura-Royo (UPC) and Xavier Gir{\'o}-i-Nieto (UPC)

Studies: Bachelor degree in Science and Telecommunication Technologies Engineering at\ Telecom BCN-ETSETB\ from the Technical University of Catalonia (UPC)

Grade: A (9.0/10.0)

The motivation of this work is the efficient exploration of hierarchical partitions for semantic segmentation as a method for locating objects in images. While many efforts have been focused on efficient image search in large-scale databases, few works have addressed the problem of locating and recognizing objects efficiently within a given image. My work considers as an input a hierarchical partition of an image that defines a set of regions as candidate locations to contain an object. This approach will be compared to other state of the art algorithms that extract object candidates for an image. The final goal of this work is to semantically segment images efficiently by exploiting the multiscale information provided by a hierarchical partition, maximizing the accuracy of the segmentation when only a very few regions of the partition are analysed.

Efficient exploration of region hierarchies for semantic segmentation from Xavier Giro

}, author = {M{\'\i}riam Bellver}, editor = {Ventura, C. and Xavier Gir{\'o}-i-Nieto} } @conference {cVentura, title = {Improving Spatial Codification in Semantic Segmentation}, booktitle = {IEEE International Conference on Image Processing (ICIP), 2015}, year = {2015}, month = {09/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Quebec City}, abstract = {

This paper explores novel approaches for improving the spatial codification for the pooling of local descriptors to solve the semantic segmentation problem. We propose to partition the image into three regions for each object to be described: Figure, Border and Ground. This partition aims at minimizing the influence of the image context on the object description and vice versa by introducing an intermediate zone around the object contour. Furthermore, we also propose a richer visual descriptor of the object by applying a Spatial Pyramid over the Figure region. Two novel Spatial Pyramid configurations are explored: Cartesian-based and crown-based Spatial Pyramids. We test these approaches with state-of-the-art techniques and show that they improve the Figure-Ground based pooling in the Pascal VOC 2011 and 2012 semantic segmentation challenges.

Improving Spatial Codification in Semantic Segmentation from Xavier Giro
}, url = {http://arxiv.org/abs/1505.07409}, author = {Ventura, C. and Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Kevin McGuinness and Marqu{\'e}s, F. and O{\textquoteright}Connor, N.} } @article {xVentura, title = {Improving Spatial Codification in Semantic Segmentation (Supplementary Material)}, year = {2015}, month = {09/2015}, abstract = {

This document contains supplementary material for the paper "Improving Spatial Codification in Semantic Segmentation" submitted to ICIP 2015. First, there is a section dedicated to the results obtained by categories when ideal object candidates (ground truth masks) are used. Then, an analysis of the results using CPMC and MCG object candidates also detailed by categories. Finally, visual results for CPMC and MCG are showed.

}, author = {Ventura, C. and Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Kevin McGuinness and Marqu{\'e}s, F. and Noel E. O{\textquoteright}Connor} } @mastersthesis {xAlfaro15, title = {Inclusion of depth information on a temporal hierarchical co-clustering technique}, year = {2015}, abstract = {

Video segmentation aims to consistently group regions that are similar in appearance and movement along a sequence. This task is an essential step of video analysis and it has important applications in video coding, indexing and retrieval, 3D reconstruction, action recognition, etc. In particular, in this thesis, a multiresolution hierarchical co-clustering technique (MRHC) is analyzed in order to include depth information for improving image segmentation in sequences with small variations. This information is invariant to changes on brightness and/or texture and camera position. Thus, it may correct some errors that are present when segmentation techniques based on color and movement are used, because this information is independent of color information of the image and the movement that occurs in the scene.

Two considerations can be made. Firstly, all the regions of the same object should share similar depth values and, secondly, depth values from regions that do not belong to the same object show discontinuities. Three different ways of coding depth information in MRHC have been studied in this project. In the first approach, the similarity between regions is weighted according to the depth difference between them. The second approach determines the 3D-neighborhood between regions. Finally, a combination of the previous approaches is considered.

The Video Occlusion/Object Boundary Dataset has been used to evaluate the inclusion of the depth on MRHC and to compare this method with the state-of-the-art techniques in the field of video segmentation. The results obtained show that the use of depth information improves the outcome video techniques obtained with the MRHC, outperforming the state-of-the-art methods in this scenario.

}, author = {Alfaro, M.}, editor = {David Varas and Marqu{\'e}s, F.} } @conference {cVaras15, title = {Multiresolution hierarchy co-clustering for semantic segmentation in sequences with small variations}, booktitle = {ICCV - International Conference on Computer Vision}, year = {2015}, month = {12/2015}, abstract = {

This paper presents a co-clustering technique that, given a collection of images and their hierarchies, clusters nodes from these hierarchies to obtain a coherent multiresolution representation of the image collection. We formalize the co-clustering as a Quadratic Semi-Assignment Problem and solve it with a linear programming relaxation approach that makes effective use of information from hierarchies. Initially, we address the problem of generating an optimal, coherent partition per image and, afterwards, we extend this method to a multiresolution framework. Finally, we particularize this framework to an iterative multiresolution video segmentation algorithm in sequences with small variations. We evaluate the algorithm on the Video Occlusion/Object Boundary Detection Dataset, showing that it produces state-of-the-art results in these scenarios.\ 

}, url = {http://arxiv.org/abs/1510.04842}, author = {David Varas and Alfaro, M. and Marqu{\'e}s, F.} } @article {aValero15, title = {Object recognition in hyperspectral images using Binary Partition Tree representation}, journal = {Pattern Recognition Letters}, volume = {56}, year = {2015}, month = {04/2015}, pages = {45-51}, abstract = {

In this work, an image representation based on Binary Partition Tree is proposed for object detection in hyperspectral images. This hierarchical region-based representation can be interpreted as a set of hierarchical regions stored in a tree structure, which succeeds in presenting: (i) the decomposition of the image in terms of coherent regions and (ii) the inclusion relations of the regions in the scene. Hence, the BPT representation defines a search space for constructing a robust object identification scheme. Spatial and spectral information are integrated in order to analyze hyperspectral images with a region-based perspective. For each region represented in the BPT, spatial and spectral descriptors are computed and the likelihood that they correspond to an instantiation of the object of interest is evaluated. Experimental results demonstrate the good performances of this BPT-based approach.

}, issn = {0167-8655}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @mastersthesis {xLopez15, title = {Reconstrucci{\'o} de la forma del rostre a partir de contorns}, year = {2015}, abstract = {

La reconstrucci{\'o} i el modelatge de cares 3D s{\textquoteright}han convertit en els {\'u}ltims anys en una l{\'\i}nia d{\textquoteright}investigaci{\'o} molt activa a causa de la seva utilitzaci{\'o} en gran nombre d{\textquoteright}aplicacions com s{\'o}n el reconeixement facial en 3D, modelatge de cares en videojocs, cirurgia est{\`e}tica, etc. Durant les {\'u}ltimes d{\`e}cades s{\textquoteright}han desenvolupat m{\'u}ltiples t{\`e}cniques computacionals de reconstrucci{\'o} facial 3D. Una de les tecnologies m{\'e}s utilitzades est{\`a} basada en imatges 2D i m{\`e}todes estad{\'\i}stics (3D Morphable Models). L{\textquoteright}estimaci{\'o} de la forma de la cara abordada amb models estad{\'\i}stics, t{\'e} com a objectiu principal trobar un conjunt de par{\`a}metres de la cara que millor s{\textquoteright}ajusten a una imatge o un conjunt d{\textquoteright}imatges. Per a aquest projecte es disposa d{\textquoteright}un model estad{\'\i}stic capa{\c c} d{\textquoteright}estimar la forma 3D del rostre quan una cara o un conjunt de contorns 2D est{\`a} disponible des de m{\'u}ltiples punts de vista. Aquest model estima directament l{\textquoteright}estructura de la cara 3D mitjan{\c c}ant l{\textquoteright}{\'u}s d{\textquoteright}una matriu de regressi{\'o} constru{\"\i}da a trav{\'e}s de PLS (Partial Least Squares). Despr{\'e}s de la validaci{\'o} del model i els bons resultats obtinguts en la predicci{\'o} de subjectes sint{\`e}tics, aquest treball proposa un nou enfoc, entrenar el model amb subjectes reals a partir d{\textquoteright}una seq{\"u}{\`e}ncia de v{\'\i}deo. D{\textquoteright}aquesta forma s{\textquoteright}obtenen reconstruccions de la forma de la cara 3D amb dades reals. Per tant, l{\textquoteright}objectiu d{\textquoteright}aquest projecte {\'e}s la definici{\'o}, la implementaci{\'o} software i l{\textquoteright}an{\`a}lisi d{\textquoteright}un procediment que ens permeti ajustar un model estad{\'\i}stic facial tridimensional gen{\`e}ric a les caracter{\'\i}stiques facials espec{\'\i}fiques d{\textquoteright}un individu a partir dels contorns del seu rostre.

}, author = {Laia del Pino L{\'o}pez}, editor = {Ver{\'o}nica Vilaplana and Josep Ramon Morros} } @mastersthesis {xGirbau15, title = {Region-based Particle Filter}, year = {2015}, abstract = {

In this project the implementation of a video object tracking technique based on a particle filter that uses the partitions of the various frames in the video has been tackled. This is an extension of the standard particle filter tracker in which unions of regions of the image are used to generate particles. By doing so, the tracking of the object of interest through the video sequence is expected to be done in a more accurate and robust way. One of the main parts of this video object tracker is a co-clustering technique that allows having an initial estimation of the object in the current frame, relying on the instance of the same object in a previous frame. While developing the object tracker, we realized the importance of this co-clustering technique, not only in the context of the current video tracker but as a basic tool for several of the research projects in the image group. Therefore, we decided to concentrate on the implementation of a generic, versatile co-clustering technique instead of the simple version that was necessary for the tracking problem. This way, the main goal of this project consists on implementing the co-clustering method presented in an accurate way while presenting a low computation time. Moreover, the complete Region-based particle filter for tracking purposes is presented. Therefore, the aim of this Final Degree Project is, mainly, to give a guideline to future researchers who will use this algorithm; to help understand and apply the mentioned co-clustering for any project in need of this method.

}, url = {http://upcommons.upc.edu/bitstream/handle/2099.1/25370/Andreu_Girbau_Xalabarder_TFG.pdf?sequence=4\&isAllowed=y}, author = {Girbau Xalabarder, A.}, editor = {David Varas and Marqu{\'e}s, F.} } @article {aVilaplana, title = {Saliency Maps on Image Hierarchies}, journal = {Signal Processing: Image Communication. Special Issue on Recent Advances in Saliency Models, Applications and Evaluations}, volume = {38}, year = {2015}, pages = {84-99}, abstract = {

In this paper we propose two saliency models for salient object segmentation based on a hierarchical image segmentation, a tree-like structure that represents regions at di erent scales from the details to the whole image (e.g. gPb-UCM, BPT). The first model is based on a hierarchy of image partitions. The saliency at each level is computed on a region basis, taking into account the contrast between regions. The maps obtained for the di erent partitions are then integrated into a nal saliency map. The second model directly works on the structure created by the segmentation algorithm, computing saliency at each node and integrating these cues in a straightforward manner into a single saliency map. We show that the proposed models produce high quality saliency maps. Objective evaluation demonstrates that the two methods achieve state-of-the-art performance in several benchmark datasets.

}, issn = {0923-5965}, author = {Ver{\'o}nica Vilaplana} } @conference {cIndia15, title = {UPC System for the 2015 MediaEval Multimodal Person Discovery in Broadcast TV task}, booktitle = {MediaEval 2015 Workshop}, year = {2015}, month = {09/2015}, address = {Wurzen, Germany}, abstract = {

This paper describes a system to identify people in broadcast TV shows in a purely unsupervised manner. The system outputs the identity of people that appear, talk and can be identified by using information appearing in the show (in our case, text with person names). Three types of monomodal technologies are used: speech diarization, video diarization and text detection / named entity recognition. These technologies are combined using a linear programming approach where some restrictions are imposed.

}, author = {India, M. and David Varas and Ver{\'o}nica Vilaplana and Morros, J.R. and Hernando, J.} } @article {aTochon15, title = {On the use of binary partition trees for the tree crown segmentation of tropical rainforest hyperspectral images}, journal = {Remote Sensing of Environment}, volume = {159}, year = {2015}, month = {03/2015}, pages = {318-331}, abstract = {

The segmentation of remotely sensed images acquired over tropical forests is of great interest for numerous ecological applications, such as forest inventories or conservation and management of ecosystems, for which species classification techniques and estimation of the number of individuals are highly valuable inputs. In this paper, we propose a method for hyperspectral image segmentation, based on the binary partition tree (BPT) algorithm, and we apply it to two sites located in Hawaiian and Panamean tropical rainforests. Different strategies combining spatial and spectral dimensionality reduction are compared prior to the construction of the BPT. Various superpixel generation methods including watershed transformation and mean shift clustering are applied to decrease spatial dimensionality and provide an initial segmentation map. Principal component analysis is performed to reduce the spectral dimensionality and different combinations of principal components are compared. A non-parametric region model based on histograms, combined with the diffusion distance to merge regions, is used to build the BPT. An adapted pruning strategy based on the size discontinuity of the merging regions is proposed and compared with an already existing pruning strategy. Finally, a set of criteria to assess the quality of the tree segmentation is introduced. The proposed method correctly segmented up to 68\% of the tree crowns and produced reasonable patterns of the segmented landscapes.

}, issn = {0034-4257}, author = {G. Tochon and J.B. F{\'e}eret and Valero, S. and R.E. Martin and D.E. Knapp and Salembier, P. and Chanussot, J. and G. Asner} } @conference {cMartinez14, title = {3D Shape Reconstruction from a Humanoid Generated Video Sequence}, booktitle = {IEEE International Conference on Humanoid Robots}, year = {2014}, address = {Madrid}, abstract = {

This paper presents a strategy for estimating the\ geometry of an interest object from a monocular video sequence\ acquired by a walking humanoid robot. The problem is solved\ using a space carving algorithm, which relies on both the\ accurate extraction of the occluding boundaries of the object as well as the precise estimation of the camera pose for each video frame. For data acquisition, a monocular visual-based control has been developed that drives the trajectory of the robot around an object placed on a small table. Due to the stepping of the humanoid, the recorded sequence is contaminated with\ artefacts that affect the correct extraction of contours along the\ video frames. To overcome this issue, a method that assigns a fitness score for each frame is proposed, delivering a subset\ of camera poses and video frames that produce consistent 3D shape estimations of the objects used for experimental evaluation.

}, author = {Mart{\'\i}nez, P. A. and David Varas and Castel{\'a}n, M and Camacho, M and Marqu{\'e}s, F. and Arechavaleta, G.} } @mastersthesis {xQueralt14, title = {Automatic Human Detection and Tracking for Robust Video Sequence Annotation}, year = {2014}, author = {Ramon Llorca Queralt}, editor = {Morros, J.R. and David Varas} } @mastersthesis {xEscue, title = {Bundling interest points for object classification}, year = {2014}, abstract = {

Advisors: Xavier Giro-i-Nieto and Carles Ventura-Royo

Bundling interest points for object classification from Xavi Gir{\'o}

This Bachelor of Science thesis addresses the problem of image classification combining two popular visual representations: points and regions. Firstly, the study explores bundling interest points with regions. These regions are generated with an initial SLIC partition and using Binary Partition Tree (BPT), considering different scales of resolution in the segmentation. Secondly, it explores modelling visual classes as a group of points extracted from different images. Based on Naive-Bayes Nearest Neighbor (NBNN), we are using 1-Nearest Neighbor with SURF descriptor on the 17 Category Flower Dataset with 1360 images of flowers distributed into 17 classes, 80 images per class. We have verified that grouping interest points of the same class improves the F1-score a 9.2\%. However, bundling interest points into regions using segmentation worsens the F1-score between 1\% and 7\%, depending on the number of regions in the segmentation.

[Extended summary on Bitsearch blog]

Author{\textquoteright}s website: jordisanchez.info

Grade: A (9.3/10)

(This BSc thesis was written in Catalan language.)

---------------------------------

Aquest Treball Final de Grau aborda el problema de la classificaci{\'o} d{\textquoteright}imatges combinant dues representacions visuals populars: els punts i les regions. En primer lloc, l{\textquoteright}estudi explora l{\textquoteright}agrupaci{\'o} de punts d{\textquoteright}inter{\`e}s amb les regions. Aquestes regions es generen amb una partici{\'o} inicial SLIC i s{\textquoteright}utilitzen els Arbres de Partici{\'o} Bin{\`a}ria (Binary Partition Tree, BPT), considerant diferents escales de resoluci{\'o} en la segmentaci{\'o}. En segon lloc, s{\textquoteright}estudia modelar les classes com a grup de punts d{\textquoteright}inter{\`e}s extrets d{\textquoteright}imatges diferents. Basant-nos en el classificador Naive-Bayes Nearest Neighbor (NBNN), hem utilitzat el ve{\"\i} m{\'e}s proper amb un descriptor SURF sobre la base de dades 17 Category Flower Dataset, que cont{\'e} 1360 imatges de flors distribu{\"\i}des en 17 classes, amb 80 imatges per classe. Hem pogut verificar que el fet d{\textquoteright}ajuntar els punts d{\textquoteright}inter{\`e}s de les imatges d{\textquoteright}una mateixa classe millora la puntuaci{\'o} F1 en un 9,2\%. No obstant, l{\textquoteright}agrupaci{\'o} de punts d{\textquoteright}inter{\`e}s en regions utilitzant una segmentaci{\'o} de la imatge empitjora la puntuaci{\'o} F1 entre l{\textquoteright}1\% i el 7\%, depenent del nombre de regions de la segmentaci{\'o}.

Lloc web de l{\textquoteright}autor: jordisanchez.info

Qualificaci{\'o}: A (9.3/10)

Jordi Sanchez Escue

}, keywords = {Bundling interest points, Digital Images, image classification, Images, Nearest Neighbor, SURF}, url = {http://hdl.handle.net/2099.1/22672}, author = {S{\'a}nchez-Escu{\'e}, Jordi}, editor = {Ventura, C. and Xavier Gir{\'o}-i-Nieto} } @mastersthesis {xGutierrez14, title = {Comparaci{\'o} d{\textquoteright}algoritmes de classificaci{\'o} de tipus de pla en imatges de futbol}, year = {2014}, abstract = {

The purpose of this project is to analyze and evaluate football image viewpoint classification algorithms and to implement, if it is possible, a set of upgrades to improve the results of this classification. In particular, the analysis of a publication of the State of the Art and its subsequent comparison to an algorithm created by the Image Processing Group (GPI) of the Polytechnic University of Catalonia is formulated. Sometimes, during the analysis process of sporting events is interesting to automate the extraction of semantic content. In this context, the algorithms compared in this project are football image viewpoint classification algorithms. To carry through the classification, these algorithms use different descriptors calculated on the images. This project originates from the need to compare the image processing group algorithm to present techniques, in order to assess the obtained results and have a better understanding of the current State of the Art. Thus, the State of the Art algorithm will be implemented, analyzed and improved if possible. Then, it will be compared to the one created by the image processing group using an extensive database previously selected. Finally, the results will be presented and analyzed.

}, url = {http://upcommons.upc.edu/bitstream/handle/2099.1/20890/Final_Report.pdf?sequence=4\&isAllowed=y}, author = {Coronado Guti{\'e}rrez, D}, editor = {David Varas and Marqu{\'e}s, F.} } @conference {cMcGuinness, title = {Insight Centre for Data Analytics (DCU) at TRECVid 2014: Instance Search and Semantic Indexing Tasks}, booktitle = {2014 TRECVID Workshop}, year = {2014}, month = {11/2014}, publisher = {National Institute of Standards and Technology (NIST)}, organization = {National Institute of Standards and Technology (NIST)}, address = {Orlando, Florida (USA)}, abstract = {

Insight-DCU participated in the instance search (INS) and semantic indexing (SIN) tasks in 2014. Two very different approaches were submitted for instance search, one based on features extracted using pre-trained deep convolutional neural networks (CNNs), and another based on local SIFT features, large vocabulary visual bag-of-words aggregation, inverted index-based lookup, and geometric verification on the top-N retrieved results. Two interactive runs and two automatic runs were submitted, the best interactive runs achieved a mAP of 0.135 and the best automatic 0.12. Our semantic indexing runs were based also on using convolutional neural network features, and on Support Vector Machine classifiers with linear and RBF kernels. One run was submitted to the main task, two to the no annotation task, and one to the progress task. Data for the no-annotation task was gathered from Google Images and ImageNet. The main task run has achieved a mAP of 0.086, the best no-annotation runs had a close performance to the main run by achieving a mAP of 0.080, while the progress run had 0.043.

[2014 TREC Video Retrieval Evaluation Notebook Papers and Slides]

Poster

}, url = {http://hdl.handle.net/2117/24915}, author = {Kevin McGuinness and Mohedano, Eva and Zhang, ZhenXing and Hu, Feiyan and Albatal, Rami and Gurrin, Cathal and O{\textquoteright}Connor, N. and Smeaton, Alan F. and Amaia Salvador and Xavier Gir{\'o}-i-Nieto and Ventura, C.} } @conference {cMorros14, title = {Materials transversals per a l{\textquoteright}aprenentatge actiu de les mat{\`e}ries de processat d{\textquoteright}imatge i v{\'\i}deo}, booktitle = {Congr{\'e}s Internacional de Doc{\`e}ncia Universit{\`a}ria i Innovaci{\'o} (CIDUI)}, year = {2014}, month = {07/2014}, address = {Tarragona, Spain}, abstract = {

This work aims to promote the cooperation and coordination between different image/video processing courses taught at the UPC in order to enhance the learning results. The main contributions are a) the creation of a common set of materials: graphical demonstrators, collections of problems, question banks, etc. and b) the design of strategies strategies to use this material in the development of generic and specific skills, with special emphasis on promoting independent learning

}, keywords = {image/video processing, Matlab demonstrators, question Banks, specific skills, teaching material}, author = {Morros, J.R. and Ver{\'o}nica Vilaplana and Ruiz-Hidalgo, J. and Casas, J. and Gasull, A. and Marqu{\'e}s, F. and M. Pard{\`a}s and Salembier, P.} } @article {aBarkhuus14, title = {New interaction modes for rich panoramic live video experiences}, journal = {Behaviour \& Information Technology}, volume = {33}, year = {2014}, month = {07/2014}, chapter = {859-869}, abstract = {

The possibilities of panoramic video are based on the capabilities of high-resolution digital video streams and higher band- width{\textquoteright}s opportunities to broadcast, stream and transfer large content across platforms. With these opportunities also come challenges such as how to focus on sub-parts of the video stream and interact with the content shown on a large screen. In this paper, we present studies of two different interaction modes with a large-scale panoramic video for live experiences; we focus on interactional challenges and explore if it is (1) possible to develop new interactional methods/ways of approaching this type of high-resolution content and (2) feasible for users to interact with the content in these new ways. We developed prototypes for two different interaction modes: an individual system on a mobile device, either a tablet or a mobile phone, for interacting with the content on the same and a non-touch gesture-based system for the home or small group interaction. We present pilot studies where we explore the possibilities and challenges with these two interaction modes for panoramic content.

}, keywords = {interaction modes, interactive television, panoramic video, pilot studies}, doi = {10.1080/0144929X.2014.914975}, url = {http://www.tandfonline.com/doi/full/10.1080/0144929X.2014.914975}, author = {Barkhuus, Louise and Zoric, Goranka and Engstr{\"o}m, Arvid and Ruiz-Hidalgo, J. and Verzijp, Nico} } @conference {cVaras14, title = {Region-based Particle Filter for Video Object Segmentation}, booktitle = {CVPR - Computer Vision and Pattern Recognition}, year = {2014}, publisher = {IEEE}, organization = {IEEE}, address = {Ohio}, abstract = {

We present a video object segmentation approach that\ extends the particle filter to a region-based image representation. Image partition is considered part of the particle filter measurement, which enriches the available information and leads to a re-formulation of the particle filter.\ The prediction step uses a co-clustering between the previous image object partition and a partition of the current\ one, which allows us to tackle the evolution of non-rigid\ structures. Particles are defined as unions of regions in the\ current image partition and their propagation is computed\ through a single co-clustering. The proposed technique is\ assessed on the SegTrack dataset, leading to satisfactory\ perceptual results and obtaining very competitive pixel error rates compared with the state-of-the-art methods.

}, keywords = {co-clustering, particle filter, segmentation, tracking}, author = {David Varas and Marqu{\'e}s, F.} } @conference {cVentura13, title = {Automatic Keyframe Selection based on Mutual Reinforcement Algorithm}, booktitle = {CBMI (Content-Based Multimedia Indexing)}, year = {2013}, month = {09/2013}, address = {Veszprem}, abstract = {

This paper addresses the problem of video summarization through an automatic selection of a single representative keyframe. The proposed solution is based on the mutual reinforcement paradigm, where a keyframe is selected thanks to its highest and most frequent similarity to the rest of considered frames. Two variations of the algorithm are explored: a first one where only frames within the same video are used (intraclip mode) and a second one where the decision also depends on the previously selected keyframes of related videos (interclip mode). These two algorithms were evaluated by a set of
professional documentalists from a broadcaster{\textquoteright}s archive, and results concluded that the proposed techniques outperform the semi-manual solution adopted so far in the company.

http://cbmi2013.mik.uni-pannon.hu/

Automatic Keyframe Selection based on Mutual Reinforcement Algorithm from Xavi Gir{\'o}
}, keywords = {mutual reinforcement algorithm, video summarization}, isbn = {978-1-4799-0955-1}, doi = {10.1109/CBMI.2013.6576548}, url = {http://dx.doi.org/10.1109/CBMI.2013.6576548}, author = {Ventura, C. and Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Daniel Giribet and Eusebio Carasusan} } @mastersthesis {xGarcia-delMolino13, title = {Extension of Instance Search Technique by Geometric Coding and Quantization Error Compensation}, year = {2013}, abstract = {

This MSc thesis analyzes two ways of improving the video retrieval techniques for instance search problem. In one hand, "Pairing Interest Points for a better Signature using Sparse Detector{\textquoteright}s Spatial Information", allows the Bag-of-Words model to keep some spatial information. In the other, "Study of the Hamming Embedding Signature Symmetry in Video Retrieval" provides binary signatures that refine the matching based on visual words, and aims to find the best way of matching taking into account the existent asymmetries between image query and videos.

}, url = {http://hdl.handle.net/2099.1/19159}, author = {Garcia-delMolino, Ana}, editor = {Satoh, Shin{\textquoteright}ichi and Ventura, C. and Xavier Gir{\'o}-i-Nieto} } @article {aValero13, title = {Hyperspectral image representation and processing with Binary Partition Trees}, journal = {IEEE Transactions on Image Processing}, volume = {22}, year = {2013}, month = {April 2013}, pages = {1430 - 1443}, abstract = {

The optimal exploitation of the information provided by hyperspectral images requires the development of advanced image-processing tools. This paper proposes the construction and the processing of a new region-based hierarchical hyperspectral image representation relying on the binary partition tree (BPT). This hierarchical region-based representation can be interpreted as a set of hierarchical regions stored in a tree structure. Hence, the BPT succeeds in presenting: 1) the decomposition of the image in terms of coherent regions, and 2) the inclusion relations of the regions in the scene. Based on region-merging techniques, the BPT construction is investigated by studying the hyperspectral region models and the associated similarity metrics. Once the BPT is constructed, the fixed tree structure allows implementing efficient and advanced application-dependent techniques on it. The applicationdependent processing of BPT is generally implemented through a specific pruning of the tree. In this paper, a pruning strategy is proposed and discussed in a classification context. Experimental results on various hyperspectral data sets demonstrate the interest and the good performances of the BPT representation.

}, doi = {10.1109/TIP.2012.2231687}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @article {aVentura13, title = {Improving retrieval accuracy of Hierarchical Cellular Trees for generic metric spaces}, journal = {Multimedia Tools and Applications}, year = {2013}, abstract = {

Metric Access Methods (MAMs) are indexing techniques which allow working in generic metric spaces. Therefore, MAMs are specially useful for Content-Based Image Retrieval systems based on features which use non Lp norms as similarity measures. MAMs naturally allow the design of image browsers due to their inherent hierarchical structure. The Hierarchical Cellular Tree (HCT), a MAM based indexing technique, provides the starting point of our work. In this paper, we describe some limitations detected in the original formulation of the HCT and propose some modifications to both the index building and the search algorithm. First, the covering radius, which is defined as the distance from the representative to the furthest element in a node,may not cover all the elements belonging to the node{\textquoteright}s subtree. Therefore, we propose to redefine the covering radius as the distance from the representative to the furthest element in the node{\textquoteright}s subtree. This new definition is essential to guarantee a correct construction of the HCT. Second, the proposed Progressive Query retrieval scheme can be redesigned to perform the nearest neighbor operation in a more efficient way. We propose a new retrieval scheme which takes advantage of the benefits of the search algorithm used in the index building. Furthermore, while the evaluation of the HCT in the original work was only subjective, we propose an objective evaluation based on two aspects which are crucial in any approximate search algorithm: the retrieval time and the retrieval accuracy. Finally, we illustrate the usefulness of the proposal by presenting some actual applications.

}, doi = {10.1007/s11042-013-1686-3}, author = {Ventura, C. and Ver{\'o}nica Vilaplana and Xavier Gir{\'o}-i-Nieto and Marqu{\'e}s, F.} } @conference {cValero13, title = {Object recognition in urban hyperspectral images using binary partition tree representation}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS{\textquoteright}2013}, year = {2013}, publisher = {IEEE}, organization = {IEEE}, address = {Melbourne, Australia}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @article {aAlonso-Gonzalez13, title = {Processing Multidimensional SAR and Hyperspectral Images With Binary Partition Tree}, journal = {Proceedings of the IEEE}, volume = {101}, year = {2013}, month = {March, 2013}, pages = {723 - 747}, chapter = {723 - 747}, abstract = {

The current increase of spatial as well as spectral resolutions of modern remote sensing sensors represents a real opportunity for many practical applications but also generates important challenges in terms of image processing. In particular, the spatial correlation between pixels and/or the spectral correlation between spectral bands of a given pixel cannot be ignored. The traditional pixel-based representation of images does not facilitate the handling of these correlations.

In this paper, we discuss the interest of a particular hierarchical region-based representation of images based on binary partition tree (BPT). This representation approach is very flexible as it can be applied to any type of image. Here both optical and radar images will be discussed. Moreover, once the image representation is computed, it can be used for many different applications. Filtering, segmentation, and classification will be detailed in this paper. In all cases, the interest of the BPT representation over the classical pixel-based representation will be highlighted.

}, doi = {10.1109/JPROC.2012.2205209}, author = {Alonso-Gonz{\'a}lez, A. and Valero, S. and Chanussot, J. and L{\'o}pez-Mart{\'\i}nez, C. and Salembier, P.} } @inbook {bLeon13, title = {Region-based caption text extraction}, booktitle = {Lecture Notes in Electrical Engineering (Analysis, Retrieval and Delivery of Multimedia Content)}, volume = {158}, year = {2013}, month = {07/2012}, pages = {21-36}, publisher = {Springer}, organization = {Springer}, address = {New York}, abstract = {

This chapter presents a method for caption text detection. The proposed method will be included in a generic indexing system dealing with other semantic concepts which are to be automatically detected as well. To have a coherent detection system, the various object detection algorithms use a common image description, a hierarchical region-based image model. The proposed method takes advantage of texture and geometric features to detect the caption text. Texture features are estimated using wavelet analysis and mainly applied for\ text candidate spotting. In turn,\ text characteristics verification\ relies on geometric features, which are estimated exploiting the region-based image model. Analysis of the region hierarchy provides the final caption text objects. The final step of\ consistency analysis for output\ is performed by a binarization algorithm that robustly estimates the thresholds on the caption text area of support.

}, keywords = {Text detection}, isbn = {978-1-4614-3830-4}, doi = {10.1007/978-1-4614-3831-1_2}, author = {Le{\'o}n, M. and Ver{\'o}nica Vilaplana and Gasull, A. and Marqu{\'e}s, F.} } @conference {cVilaplana13, title = {Salient Object Detection on a Hierarchy of Image Partitions}, booktitle = {IEEE Int. Conf. in Image Processing, ICIP 2013}, year = {2013}, month = {09/2013}, address = {Melbourne, Australia}, author = {Ver{\'o}nica Vilaplana and G. Muntaner} } @article {aTochon13, title = {Segmentation hyperspectrales de forets tropicales par arbres de partition binaires}, journal = {Revue fran{\c c}aise de photogramm{\'e}trie et de t{\'e}l{\'e}d{\'e}tection}, volume = {202}, year = {2013}, month = {May 2013}, pages = {55-65}, author = {G. Tochon and J.B. Feret and Valero, S. and R.E. Martin and R. Tupayachi and Chanussot, J. and Salembier, P. and G. Asner} } @conference {cVentura13a, title = {UPC at MediaEval 2013 Hyperlinking Task}, booktitle = {MediaEval 2013 Workshop}, year = {2013}, month = {10/2013}, publisher = {CEUR Workshop Proceedings Vol-1043}, organization = {CEUR Workshop Proceedings Vol-1043}, address = {Barcelona, Catalonia}, abstract = {

These working notes paper present the contribution of the UPC team to the Hyperlinking sub-task of the Search and Hyperlinking Task in MediaEval 2013. Our contribution explores the potential of a solution based only on visual cues.

In particular, every automatically generated shot is represented by a keyframe. The linking between video segments is based on the visual similarity of the keyframes they contain. Visual similarity is assessed with the intersection of bag of features histograms generated with the SURF descriptor.

Xavier Gir{\'o}, "UPC at MediaEval Hyperlinking 2013" from Xavi Gir{\'o}

Presentation on MediaEval Search \& Linking task 2013 from Netherlands Institute for Sound and Vision, University of Twente
}, keywords = {Benchmark, Hyperlinking, Video Collections}, url = {http://ceur-ws.org/Vol-1043/mediaeval2013_submission_35.pdf}, author = {Ventura, C. and Tella, Marcel and Xavier Gir{\'o}-i-Nieto} } @mastersthesis {xVentura13, title = {Visual Object Analysis Using Regions and Interest Points}, year = {2013}, abstract = {

This dissertion research explores two of the most-used image models for object detection, 3D reconstruction, visual search: region-based and interest-points image representations; and will try to provide a new image model to take advantage of the strengths and overcome the weaknesses of both approaches. More specifically, we will focus on the gPb-owt-ucm segmentation algorithm and the SIFT local features since they are the most contrasted techniques in their respective fields. Furthermore, using an object retrieval benchmark, this dissertation research will analyze three basic questions: (i) the usefulness of an interest points hierarchy based on a contour strength signal, (ii) the influence of the context on both interest points location and description, and (iii) the analysis of regions as spatial support for bundling interest points.\ 

}, author = {Ventura, C.}, editor = {Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @mastersthesis {cVentura13b, title = {Visual Object Analysis Using Regions and Interest Points}, journal = {ACM Multimedia}, year = {2013}, month = {10/2013}, abstract = {

This dissertation research will explore region-based and interest points based image representations, two of the most-used image models for object detection, image classification, and visual search among other applications. We will analyze the relationship between both representations with the goal of proposing a new hybrid representation that takes
advantage of the strengths and overcomes the weaknesses of both approaches. More specifically, we will focus on the gPb-owt-ucm segmentation algorithm and the SIFT local features since they are the most contrasted techniques in their respective fields. Furthermore, using an object retrieval benchmark, this dissertation research will analyze three basic questions: (i) the usefulness of an interest points hierarchy based on a contour strength signal, (ii) the influence of the context on both interest points location and description, and (iii) the analysis of regions as spatial support for bundling interest points.

}, keywords = {hierarchical segmentation, Image Representation, Interest Points, Object Retrieval}, doi = {10.1145/2502081.2502220}, url = {http://dx.doi.org/10.1145/2502081.2502220}, author = {Ventura, C.}, editor = {Xavier Gir{\'o}-i-Nieto} } @article {aCuadras12, title = {Distance-based measures of association with applications in relating hyperspectral images}, journal = {Communications in Statistics - Theory and Method}, volume = {41}, year = {2012}, pages = {2342{\textendash}2355}, abstract = {

We propose a distance-based method to relate two data sets. We define and study some measures of multivariate association based on distances between observations. The proposed approach can be used to deal with general data sets (e.g., observations on continuous, categorical or mixed variables). An application, using Hellinger distance, provides the relationships between two regions of hyperspectral images.

}, issn = {0361-0918}, doi = {10.1080/03610926.2012.654880}, author = {Cuadras, C. and Valero, S. and Cuadras, D. and Salembier, P. and Chanussot, J.} } @inbook {bVentura12, title = {Hierarchical Navigation and Visual Search for Video Keyframe Retrieval}, booktitle = {Advances in Multimedia Modeling}, series = {Lecture Notes in Computer Science}, volume = {7131}, year = {2012}, pages = {652-654}, publisher = {Springer Berlin / Heidelberg}, organization = {Springer Berlin / Heidelberg}, abstract = {

This work presents a browser that supports two strategies for video browsing: the navigation through visual hierarchies and the retrieval of similar images. The input videos are firstly processed by a keyframe extractor to reduce the temporal redundancy and decrease the number of elements to consider. These generated keyframes are hierarchically clustered with the Hierachical Cellular Tree (HCT) algorithm, an indexing technique that also allows the creation of data structures suitable for browsing. Different clustering criteria are available, in the current implementation, based on four MPEG-7 visual descriptors computed at the global scale. The navigation can directly drive the user to find the video timestamps that best match the query or to a keyframe which is globally similar in visual terms to the query. In the latter case, a visual search engine is also available to find other similar keyframes, based as well on MPEG-7 visual descriptors.

Winners of the Novice Run at the VideoBrowser Showdown 2012 at the 18th International Conference on MultiMedia Modeling, Kalgenfurt, Austria, January 4-6, 2012.

}, keywords = {hierarchical navigation, image retrieval, video browser}, isbn = {978-3-642-27354-4}, doi = {10.1007/978-3-642-27355-1_67}, url = {http://dx.doi.org/10.1007/978-3-642-27355-1_67}, author = {Ventura, C. and Martos, Manel and Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cVaras12a, title = {A Region-Based Particle Filter for Generic Object Tracking and Segmentation}, booktitle = {ICIP - International Conference on Image Processing}, year = {2012}, month = {09/2012}, address = {Orlando}, abstract = {

In this work we present a region-based particle filter for generic object tracking and segmentation. The representation of the object in terms of regions homogeneous in color allows the proposed algorithm to robustly track the object and accurately segment its shape along the sequence. Moreover, this segmentation provides a mechanism to update the target model and allows the tracker to deal with color and shape variations of the object. The performance of the algorithm has been tested using the LabelMe Video public database.

The experiments show satisfactory results in both tracking and segmentation of the object without an important increase of the computational time due to an efficient computation of the image partition.\ 

}, doi = {http://dx.doi.org/10.1109/ICIP.2012.6467114}, author = {David Varas and Marqu{\'e}s, F.} } @conference {cValero11a, title = {Arbre de partition binaire: un nouvel outil pour la repr{\'e}sentation hi{\'e}rarchique et l{\textquoteright}analyse des images hyperspectrales}, booktitle = {XXIII{\`e} Colloque sur le Traitement du Signal et des Images, GRETSI 2011}, year = {2011}, pages = {120{\textendash}125}, address = {Bordeaux, France}, url = {http://hdl.handle.net/2117/14621}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @conference {cBenediktsson11, title = {Hierarchical analysis of remote sensing data: morphological attribute profiles and binary partition trees}, booktitle = {International Symposium on Mathematical Morphology 2011}, year = {2011}, pages = {306{\textendash}319}, address = {Intra, Lake Maggiore, Italy}, isbn = {3642215688}, doi = {10.1007/978-3-642-21569-8_27}, url = {http://hdl.handle.net/2117/14624}, author = {Benediktsson, J. and Bruzzone, L. and Chanussot, J. and Dalla Mura, M. and Salembier, P. and Valero, S.} } @phdthesis {dValero11, title = {Hyperspectral image representation and Processing with Binary Partition Trees}, year = {2011}, school = {Universitat Polit{\`e}cnica de Catalunya (UPC)}, type = {phd}, abstract = {

The optimal exploitation of the information provided by hyperspectral images requires the development of advanced image processing tools. Therefore, this PhD thesis proposes the construction and the processing of a new region-based hierarchical hyperspectral image representation: the Binary Partition Tree (BPT). This representation can be interpreted as a set of hierarchical regions stored in a tree structure. Based on region-merging techniques, the construction of BPT is investigated in this work by studying hyperspectral region models and the associated similarity metrics. Once the BPT is constructed,the fixed tree structure allows implementing efficient and advanced application-dependent techniques on it. The application-dependent processing of BPT is generally implemented through a specific pruning of the tree. Accordingly, some pruning techniques are proposed and discussed according to different applications. This Ph.D is focused in particular on segmentation, object detection and classification of hyperspectral imagery. Experimental results on various hyper spectral data sets demonstrate the interest and the good performances of the BPT representation.

}, url = {http://www.gipsa-lab.grenoble-inp.fr/formation/theses-soutenues.php?id_these=572}, author = {Valero, S.}, editor = {Salembier, P.} } @conference {cValero11b, title = {Hyperspectral image segmentation using binary partition trees}, booktitle = {IEEE International Conference on Image Processing, ICIP 2011}, year = {2011}, pages = {1273{\textendash}1276}, address = {Brussels, Belgium}, isbn = {0-7803-5470-2}, doi = {10.1109/ICIP.2011.6115666}, url = {http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6094293}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @conference {cValero11, title = {Improved binary partition tree construction for hyperspectral images: application to object detection}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2011}, year = {2011}, pages = {2515{\textendash}2518}, address = {Vancouver, Canada}, doi = {10.1109/IGARSS.2011.6049723}, url = {http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6034618}, author = {Valero, S. and Salembier, P. and Chanussot, J. and Cuadres, C.} } @mastersthesis {xAlfaro11 , title = {Reordenaci{\'o} i agrupament d{\textquoteright}imatges d{\textquoteright}una cerca de v{\'\i}deo}, year = {2011}, month = {01/2011}, abstract = {

La recuperaci{\'o} de v{\'\i}deo a trav{\'e}s de consultes textuals es una practica molt com{\'u} en els arxius de radiodifusi{\'o}. Les paraules clau de les consultes son comparades amb les metadades que s{\textquoteright}anoten manualment als assets de v{\'\i}deo pels documentalistes. A m{\'e}s, les cerques textuals b{\`a}siques generen llistes de resultats planes, on tots els resultats tenen la mateixa import{\`a}ncia, ja que, es limita a avaluar bin{\`a}riament si la paraula de cerca apareix o no entre les metadades associades als continguts. A m{\'e}s, acostumen a mostrar continguts molt similars, donant al usuari una llista ordenada de resultats de poca diversitat visual. La redund{\`a}ncia en els resultats provoca un malbaratament d{\textquoteright}espai a la interf{\'\i}cie gr{\`a}fica d{\textquoteright}usuari (GUI) que sovint obliga a l{\textquoteright}usuari a interactuar fortament amb la interf{\'\i}cie gr{\`a}fica fins localitzar els resultats rellevants per a la seva cerca. La aportaci{\'o} del present projecte consisteix en la presentaci{\'o} d{\textquoteright}una estrat{\`e}gia de reordenaci{\'o} i agrupaci{\'o} per obtenir keyframes de major rellev{\`a}ncia entre els primers resultats, per{\`o} al mateix temps mantenir una diversitat d{\textquoteright}assets. D{\textquoteright}aquesta forma, aquestes t{\`e}cniques permetran millorar els sistemes de visualitzaci{\'o} d{\textquoteright}imatges resultants d{\textquoteright}una cerca de v{\'\i}deo. L{\textquoteright}eina global es dissenya per ser integrada en l{\textquoteright}entorn del Digition, el gestor de continguts audiovisuals de la Corporaci{\'o} Catalana de Mitjans Audiovisuals.




}, url = {http://hdl.handle.net/2099.1/11106}, author = {Alfaro, M.}, editor = {Vives, X. and Xavier Gir{\'o}-i-Nieto} } @mastersthesis {x11, title = {Rich Internet Application for the Semi-Automatic Annotation of Semantic Shots on Keyframes}, year = {2011}, abstract = {

This thesis describes the graphical user interface developed for semi-automatic keyframebased semantic shot annotation and the semantic shot classifiers built. The graphical user interface aims to optimize the current indexation process by substituting manual annotation for automatic annotation and validation. The system is based on supervised learning binary classifiers and web services. The graphical user interface provides the necessary tools to fix and validate the automatic detections and to learn from the user feedback to retrain the system and improve it. Results of the classifiers evaluation, performed using cross-validation methods, show a good performance in terms of precision and recall. The graphical user interface has been described as complete and easy to use by a professional documentalist at a broadcast company.

Interfície web per l{\textquoteright}annotació semi-automàtica de plans semàntics from Xavi Gir{\'o}


}, url = {http://hdl.handle.net/2099.1/13539}, author = {Carcel, Elisabet}, editor = {Xavier Gir{\'o}-i-Nieto and Vives, X.} } @mastersthesis {xVentura11, title = {Tools for Image Retrieval in Large Multimedia Databases}, year = {2011}, abstract = {

One of the challenges in the development of an image retrieval system is to achieve an efficient indexing scheme since both developers and users, who are used to make requests in order to find a multimedia element in a large database, can be frustrated due to the long computational time of the search.

The traditional indexing schemes neither fulfil the dynamic indexing requirement, which allows to add or remove elements from the structure, nor fit well in high dimensional feature spaces due to the phenomenon so called {\textquotedblleft}the curse of dimensionality.{\textquotedblright}

After analysing several indexing techniques from the literature, we have decided to implement an indexing scheme called Hierarchical Cellular Tree (HCT), which was designed to bring an effective solution especially for indexing large multimedia databases. The HCT has allowed to improve the performance of our implemented image retrieval system based on the MPEG-7 visual descriptors. We have also made some contributions by proposing some modifications to the original HCT which have resulted in an improvement of its performance. Thus, we have proposed a redefinition of the covering radius, which does not consider only the elements belonging to the cell, but also all the elements holding from that cell. Since this consideration implies a much more computationally costly algorithm, we have proposed an approximation by excess for the covering radius value. However, we have also implemented a method which allows to update the covering radius to its actual value whenever it is desired. In addition to this, the pre-emptive insertion method has been adapted as a searching technique in order to improve the performance given by the retrieval scheme called Progressive Query, which was originally proposed to be used over the HCT.

Furthermore, the HCT indexing scheme has been also adapted to a server/client architecture by using a messenger system called KSC, which allows to have the HCT loaded on a server waiting for the query requests which are launched for the several clients of the retrieval system. In addition to this, the tool used to request a search over the indexed database has been adapted to a graphic user interface, named GOS (Graphic Object Searcher), which allows the user to order the retrievals in a more friendly way.

[Thesis report in UPCommons]

}, url = {http://hdl.handle.net/2099.1/13011}, author = {Ventura, C.}, editor = {Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cValero10a, title = {Comparison of merging orders and pruning strategies for binary partition tree in hyperspectral data}, booktitle = {IEEE International Conference on Image Processing, ICIP 2010}, year = {2010}, pages = {2565{\textendash}2568}, address = {Hong Kong, China}, doi = {10.1109/ICIP.2010.5652595}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5652595}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @conference {cGiro-i-Nieto10, title = {Digimatge, a Rich Internet Application for video retrieval from a Multimedia Asset Management system}, booktitle = {11th ACM SIGMM International Conference on Multimedia Information Retrieval}, year = {2010}, abstract = {

This paper describes the integration of two new services aimed at assisting into the retrieval of video content from an existing Multimedia Asset Manager (MAM) of a TV broadcaster archive. The first tool suggests tags after a first textual query, and the second ranks the keyframe of retrieved assets according to their visual similarity. Both applications were integrated as web services that are accessed from a Rich Internet Application via REST calls.

}, isbn = {978-1-60558-815-5}, doi = {10.1145/1743384.1743458}, url = {http://upcommons.upc.edu/e-prints/urlFiles?idDrac=2249267}, author = {Xavier Gir{\'o}-i-Nieto and Salla, R. and Vives, X.} } @mastersthesis {xmunoz-trallero10, title = {Extensi{\'o} d{\textquoteright}una interf{\'\i}cie de cerca d{\textquoteright}imatges a les consultes amb regions}, year = {2010}, abstract = {

Aquest {\'e}s un projecte universitat-empresa que presenta una interf{\'\i}cie de cerca multimodal a partir de la integraci{\'o} de diferents eines ja existents per crear una eina global que combina les cerques textuals amb les consultes mitjan{\c c}ant exemple, ja sigui una consulta basada en una imatge o en una regi{\'o} d{\textquoteright}aquesta imatge. L{\textquoteright}eina global s{\textquoteright}integra en l{\textquoteright}entorn del Digition, el gestor de continguts audiovisuals de la Corporaci{\'o} Catalana de Mitjans Audiovisuals. La principal aportaci{\'o} del present projecte consisteix en la creaci{\'o} d{\textquoteright}una interf{\'\i}cie de cerca d{\textquoteright}imatges basada en regions i la seva integraci{\'o} en l{\textquoteright}eina global.


}, url = {http://hdl.handle.net/2099.1/13525}, author = {Pia Mu{\~n}oz-Trallero}, editor = {Xavier Gir{\'o}-i-Nieto and Vives, X.} } @mastersthesis {xVentura10, title = {Image-Based Query by Example Using MPEG-7 Visual Descriptors}, year = {2010}, abstract = {

This project presents the design and implementation of a Content-Based Image Re- trieval (CBIR) system where queries are formulated by visual examples through a graphical interface. Visual descriptors and similarity measures implemented in this work followed mainly those defined in the MPEG-7 standard although, when necessary, extensions are proposed. Despite the fact that this is an image-based system, all the proposed descriptors have been implemented for both image and region queries, allowing the future system upgrade to support region-based queries. This way, even a contour shape descriptor has been developed, which has no sense for the whole image. The system has been assessed on different benchmark databases; namely, MPEG-7 Common Color Dataset, and Corel Dataset. The evaluation has been performed for isolated descriptors as well as for combinations of them. The strategy studied in this work to gather the information obtained from the whole set of computed descriptors is weighting the rank list for each isolated descriptor.\ 

}, url = {http://upcommons.upc.edu/pfc/handle/2099.1/9453}, author = {Ventura, C.}, editor = {Marqu{\'e}s, F. and Jordi Pont-Tuset} } @conference {cValero10, title = {New hyperspectral data representation using binary partition tree}, booktitle = {IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2010}, year = {2010}, pages = {80{\textendash}83}, address = {Honolulu, USA}, isbn = {978-1-4244-4761-9}, doi = {10.1109/IGARSS.2010.5649780}, url = {http://hdl.handle.net/2117/11005}, author = {Valero, S. and Salembier, P. and Chanussot, J.} } @conference {cVilaplana10, title = {Object detection and segmentation on a hierarchical region-based image representation}, booktitle = {2010 IEEE International Conference on Image Processing}, year = {2010}, pages = {3393{\textendash}3396}, isbn = {0-8194-2103-0}, url = {http://hdl.handle.net/2117/11435}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F. and Le{\'o}n, M. and Gasull, A.} } @conference {cLeon10, title = {Region-based caption text extraction}, booktitle = {11th. International Workshop on Image Analysis for Multimedia Application Services}, year = {2010}, pages = {1{\textendash}4}, url = {http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5608542}, author = {Le{\'o}n, M. and Ver{\'o}nica Vilaplana and Gasull, A. and Marqu{\'e}s, F.} } @phdthesis {dVilaplana10, title = {Region-based face detection, segmentation and tracking. framework definition and application to other objects}, year = {2010}, school = {Universitat Polit{\`e}cnica de Catalunya (UPC)}, type = {phd}, abstract = {

One of the central problems in computer vision is the automatic recognition of object classes. In particular, the detection of the class of human faces is a problem that generates special interest due to the large number of applications that require face detection as a first step. In this thesis we approach the problem of face detection as a joint detection and segmentation problem, in order to precisely localize faces with pixel accurate masks. Even though this is our primary goal, in finding a solution we have tried to create a general framework as independent as possible of the type of object being searched. For that purpose, the technique relies on a hierarchical region-based image model, the Binary Partition Tree, where objects are obtained by the union of regions in an image partition. In this work, this model is optimized for the face detection and segmentation tasks. Different merging and stopping criteria are proposed and compared through a large set of experiments. In the proposed system the intra-class variability of faces is managed within a learning framework. The face class is characterized using a set of descriptors measured on the tree nodes, and a set of one-class classifiers. The system is formed by two strong classifiers. First, a cascade of binary classifiers simplifies the search space, and afterwards, an ensemble of more complex classifiers performs the final classification of the tree nodes. The system is extensively tested on different face data sets, producing accurate segmentations and proving to be quite robust to variations in scale, position, orientation, lighting conditions and background complexity. We show that the technique proposed for faces can be easily adapted to detect other object classes. Since the construction of the image model does not depend on any object class, different objects can be detected and segmented using the appropriate object model on the same image model. New object models can be easily built by selecting and training a suitable set of descriptors and classifiers. Finally, a tracking mechanism is proposed. It combines the efficiency of the mean-shift algorithm with the use of regions to track and segment faces through a video sequence, where both the face and the camera may move. The method is extended to deal with other deformable objects, using a region-based graph-cut method for the final object segmentation at each frame. Experiments show that both mean-shift based trackers produce accurate segmentations even in difficult scenarios such as those with similar object and background colors and fast camera and object movements.

}, url = {http://hdl.handle.net/10803/33330}, author = {Ver{\'o}nica Vilaplana}, editor = {Marqu{\'e}s, F.} } @conference {cCuadras10, title = {Some measures of multivariate association relating two spectral data sets}, booktitle = {19th International Conference on Computational Statistics, COMSTAT 2010}, year = {2010}, address = {Paris, France}, author = {Cuadras, C. and Valero, S. and Salembier, P. and Chanussot, J.} } @conference {cGiro10a, title = {System architecture of a web service for Content-Based Image Retrieval}, booktitle = {ACM International Conference On Image And Video Retrieval 2010}, year = {2010}, pages = {358{\textendash}365}, abstract = {

This paper presents the system architecture of a Content-Based Image Retrieval system implemented as a web service. The proposed solution is composed of two parts, a client running a graphical user interface for query formulation and a server where the search engine explores an image repository. The separation of the user interface and the search engine follows a Service as a Software (SaaS) model, a type of cloud computing design where a single core system is online and available to authorized clients. The proposed architecture follows the REST software architecture and HTTP protocol for communications, two solutions that combined with metadata coded in RDF, make the proposed system ready for its integration in the semantic web. User queries are formulated by visual examples through a graphical interface and content is remotely accessed also through HTTP communication. Visual descriptors and similarity measures implemented in this work are mostly defined in the MPEG-7 standard, while textual metadata is coded according to the Dublin Core specifications.

}, isbn = {978-1-4503-0117-6}, doi = {10.1145/1816041.1816093}, url = {http://doi.acm.org/10.1145/1816041.1816093}, author = {Xavier Gir{\'o}-i-Nieto and Ventura, C. and Jordi Pont-Tuset and Cort{\'e}s, S. and Marqu{\'e}s, F.} } @mastersthesis {xVaras10, title = {Type of view estimation in football sequences}, year = {2010}, abstract = {

Due to the huge repercussion of football broadcast in society, an enormous number of applications can be derived to both analyze the match and enhance the visual experience of the spectator. These applications request semantical information about the content of the images. In particular, the type of view in a football image contains valuable information about the game. Thus, the type of view must be automatically computed to be able to process the large amount of information extracted from each football match. In this work, we propose a robust classification system that estimates the type ofview in football images in real time. For each frame of the sequence, a set of descriptors is extracted to characterize a specific part of the scene: the grass field. Gathering all these descriptors and a few ones related with texture, a decision tree determines the view that is shown in that frame. In order to improve the robustness of the algorithm, the redundancy of the temporal domain is exploited. The validity of the proposed algorithm has been tested on a large amount of frames from broadcasted football sequences in a wide variety of scenarios (stadiums, light conditions, ...). Promising results have been obtained with a 96\% of accuracy in the classification of these images.

}, author = {David Varas}, editor = {Marqu{\'e}s, F.} } @mastersthesis {xRovira09, title = {Aplicaci{\'o} rica d{\textquoteright}internet per a la consulta amb text i imatge a la Corporaci{\'o} Catalana de Mitjans Audiovisuals}, year = {2009}, abstract = {

Premi millor projecte final de carrera d{\textquoteright}Enginyeria de Telecomunicaci{\'o} en Serveis Telem{\`a}tics. Atorgat per Accenture (Curs 2009-2010)

}, url = {http://hdl.handle.net/2099.1/8766}, author = {Salla-Rovira, Ramon}, editor = {Xavier Gir{\'o}-i-Nieto and Vives, X.} } @conference {cLeon09, title = {Caption text extraction for indexing purposes using a hierarchical region-based image model}, booktitle = {16th International Conference on Image Processing}, year = {2009}, pages = {1869{\textendash}1872}, isbn = {978-1-4244-5655-0}, doi = {http://dx.doi.org/10.1109/ICIP.2009.5413607}, url = {http://hdl.handle.net/2117/7940}, author = {Le{\'o}n, M. and Ver{\'o}nica Vilaplana and Gasull, A. and Marqu{\'e}s, F.} } @inbook {bVilaplana09, title = {Compressi{\'o} d{\textquoteright}imatges}, booktitle = {Codificaci{\'o} del so i de la imatge}, year = {2009}, pages = {1{\textendash}65}, isbn = {9788469148365}, url = {http://ccuc.cbuc.cat:2082/record=b4149618~S23*cat}, author = {Ver{\'o}nica Vilaplana} } @conference {cVilaplana09, title = {Face tracking using a region-based mean-shift algorithm with adaptive object and background models}, booktitle = {Workshop on Image Analysis for Multimedia Interactive Services}, year = {2009}, pages = {9{\textendash}12}, doi = {http://dx.doi.org/10.1109/WIAMIS.2009.5031419}, url = {http://hdl.handle.net/2117/7946}, author = {Ver{\'o}nica Vilaplana and David Varas} } @inbook {bCanton-Ferrer09, title = {Image and video processing tools for HCI}, booktitle = {Multimodal signal processing: theory and applications for human-computer interaction}, year = {2009}, pages = {93{\textendash}118}, isbn = {9780123748256}, author = {Cristian Canton-Ferrer and M. Pard{\`a}s and Ver{\'o}nica Vilaplana} } @conference {cCabrera09, title = {LAVICAD: LAboratori VIrtual de Comunicacions Anal{\`o}giques i Digitals}, booktitle = {Jornada d{\textquoteright}Innovaci{\'o} Docent - RIMA (JID-RIMA)}, year = {2009}, month = {02/2009}, publisher = {UPCommons}, organization = {UPCommons}, address = {Barcelona, Catalonia}, abstract = {

Mitjan{\c c}ant el present ajut s{\textquoteright}ha ampliat l{\textquoteright}aplicaci{\'o} en xarxa LAVICAD (LAboratori VIrtual de COmunicacions Anal{\`o}giques i Digitals) que s{\textquoteright}ofereix de forma integrada dins de la plataforma d{\textquoteright}e-learning COM@WEB. LAVICAD {\'e}s una eina programada en Java i Matlab i est{\`a} formada per un conjunt de simuladors de la capa f{\'\i}sica de sistemes de comunicacions. Tots els simuladors es presenten en xarxa i es poden utilitzar pels estudiants des de qualsevol ordinador sense necessitat d{\textquoteright}instal{\textperiodcentered}laci{\'o} de cap tipus de software especial. Durant el curs 2007 2008 s{\textquoteright}han desenvolupat entre d{\textquoteright}altres dos l{\'\i}nies de treball. D{\textquoteright}una banda s{\textquoteright}ha programat l{\textquoteright}applet que emula la capa f{\'\i}sica de la televisi{\'o} digital terrestre, com a referent per a l{\textquoteright}ensenyament de sistemes de comunicacions avan{\c c}ats. D{\textquoteright}altra banda s{\textquoteright}ha treballat en la programaci{\'o} de noves funcionalitats de l{\textquoteright}eina LAVICAD, que permeten ajudar als professors en el seguiment i avaluaci{\'o} del treball continuat dels estudiants. En particular s{\textquoteright}ha programat la generaci{\'o} d{\textquoteright}una base de dades que cont{\'e} la informaci{\'o} dels usuaris que s{\textquoteright}han connectat i els resultats obtinguts a l{\textquoteright}executar un determinat simulador. Les dues l{\'\i}nies desenvolupades han de permetre durant l{\textquoteright}actual curs, consolidar l{\textquoteright}{\'u}s dels diferents simuladors per a la doc{\`e}ncia de les assignatures implicades al projecte.

}, url = {http://hdl.handle.net/2099/7235}, author = {Cabrera, M. and Xavier Gir{\'o}-i-Nieto and Rey, F. and Gasull, A. and Casas, J. and Villares, J. and Fernandez, J. and Sala {\'A}lvarez, josep and Espinosa Fricke, Pedro and Fern{\'a}ndez, Carlos Marcos and Cort{\'e}s, S. and Farr{\'e}, Miquel {\`A}ngel} } @inbook {bVilaplana09a, title = {Processament puntual}, booktitle = {Codificaci{\'o} del so i de la imatge}, year = {2009}, pages = {5{\textendash}65}, isbn = {9788469148365}, url = {http://ccuc.cbuc.cat:2082/record=b4149618~S23*cat}, author = {Ver{\'o}nica Vilaplana} } @article {aVilaplana08, title = {Binary partition trees for object detection}, journal = {IEEE transactions on image processing}, volume = {17}, number = {11}, year = {2008}, pages = {1{\textendash}16}, abstract = {

This paper discusses the use of binary partition trees (BPTs) for object detection. BPTs are hierarchical region-based representations of images. They define a reduced set of regions that covers the image support and that spans various levels of resolution. They are attractive for object detection as they tremendously reduce the search space. In this paper, several issues related to the use of BPT for object detection are studied. Concerning the tree construction, we analyze the compromise between computational complexity reduction and accuracy. This will lead us to define two parts in the BPT: one providing accuracy and one representing the search space for the object detection task. Then we analyze and objectively compare various similarity measures for the tree construction. We conclude that different similarity criteria should be used for the part providing accuracy in the BPT and for the part defining the search space and specific criteria are proposed for each case. Then we discuss the object detection strategy based on BPT. The notion of node extension is proposed and discussed. Finally, several object detection examples illustrating the generality of the approach and its efficiency are reported.

}, issn = {1057-7149}, doi = {10.1109/TIP.2008.2002841}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F. and Salembier, P.} } @inbook {bVilaplana08, title = {Face and speech interaction}, booktitle = {Multimodal user interfaces: from signals to interaction}, year = {2008}, pages = {85{\textendash}118}, isbn = {978-3-540-78344-2}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F. and Gurban, M. and Thiran, J.} } @conference {cVilaplana08, title = {Region-based mean shift tracking: Application to face tracking}, booktitle = {IEEE International Conference on Image Processing}, year = {2008}, pages = {2712{\textendash}2715}, isbn = {978-1-4577-0538-0}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cLuque06a, title = {Audio, Video and Multimodal Person Identification in a Smart Room}, booktitle = {CLEAR{\textquoteright}06 Evaluation Campaign and Workshop - Classification of Events, Activities and Relationships}, year = {2007}, pages = {258{\textendash}269}, isbn = {978-3-540-69567-7}, author = {Luque, J. and Morros, J.R. and Garde, A. and Anguita, J. and Farr{\'u}s, M. and Macho, D. and Marqu{\'e}s, F. and Mart{\'\i}nez, C. and Ver{\'o}nica Vilaplana and Hernando, J.} } @conference {cVilaplana07b, title = {On building a hierarchical region-based representation for generic image analysis}, booktitle = {IEEE International Conference on Image Processing}, year = {2007}, isbn = {978-1-61284-467-1}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @book {eAguilar07, title = {Diccionari de Telecomunicacions}, year = {2007}, isbn = {978-84-412-1459-0}, author = {Aguilar, M. and Alcober, J. and Altes, J. and Aragones, X. and Artigas, D. and Bardes, D. and Barlabe, A. and Bragos, R. and Calderer, J. and Cardama, A. and Casademont, J. and Casals, L. and Comer{\'o}n, A. and Cotrina, J. and Cruz, L. and Federico Dios and Duxans, H. and Esparza, O. and Esquerra, I. and Garcia, D. and Garcias, P. and Gomez, C. and Gorricho, J. and Guinjoan, F. and Hesselbach, X. and Liria, A. and Lopez, J. and Madrenas, J. and Madue{\~n}o, M. and Mestre, F. and Monte, E. and Morros, J.R. and Mu{\~n}oz, J. and Pallar{\'e}s, E. and Pons, J. and Recolons, J. and Rincon, D. and Riu, P. and Pradell, L. and Pascual-Iserte, A. and Prat, L. and Rey, F. and Villares, J.} } @conference {cVilaplana07a, title = {Face detection and segmentation on a hierarchical image representation}, booktitle = {15th European Signal Processing Conference}, year = {2007}, pages = {1955{\textendash}1959}, isbn = {0-7803-7403-7}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @article {aDescampe07, title = {Prefetching and caching strategies for remote and interactive browsing of JPEG2000 images}, journal = {IEEE transactions on image processing}, volume = {16}, number = {5}, year = {2007}, pages = {1339{\textendash}1354}, issn = {1057-7149}, author = {Descampe, A. and Vleeschouwer, D. and Iregui, M. and Macq, B. and Marqu{\'e}s, F.} } @conference {cVilaplana07, title = {Region-based hierarchical representation for object detection}, booktitle = {Fith International Workshop on Content-Based Multimedia Indexing}, year = {2007}, pages = {157{\textendash}164}, isbn = {0-7803-6727-8}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @inbook {bLuque06, title = {Audio, Video and Multimodal Person Identification in a Smart Room}, booktitle = {Lecture notes in computer science - Multimodal Technologies for Perception of Humans}, volume = {4122}, year = {2006}, pages = {258{\textendash}269}, issn = {0302-9743}, doi = {10.1007/978-3-540-69568-4_23}, author = {Luque, J. and Morros, J.R. and Garde, A. and Anguita, J. and Farr{\'u}s, M. and Macho, D. and Marqu{\'e}s, F. and Mart{\'\i}nez, C. and Ver{\'o}nica Vilaplana and Hernando, J.} } @conference {cVilaplana06, title = {Face Recognition Using Groups of Images in Smart Room Scenarios}, booktitle = {International Conference on Image Processing}, year = {2006}, pages = {2071{\textendash}2074}, author = {Ver{\'o}nica Vilaplana and Mart{\'\i}nez, C. and Javier, C. and Marqu{\'e}s, F.} } @conference {cLuque06, title = {Multimodal Person Identification in a Smart Room}, booktitle = {IV Jornadas en Tecnolog{\'\i}a del Habla}, year = {2006}, pages = {327{\textendash}331}, isbn = {84-96214-82-6}, author = {Luque, J. and Morros, J.R. and Anguita, J. and Farr{\'u}s, M. and Macho, D. and Marqu{\'e}s, F. and Mart{\'\i}nez, C. and Ver{\'o}nica Vilaplana and Hernando, J.} } @inbook {bGiro-i-Nieto05, title = {Automatic extraction and analysis of visual objects information}, booktitle = {Multimedia content and the semantic web}, year = {2005}, pages = {203{\textendash}221}, publisher = {Wiley}, organization = {Wiley}, chapter = {7}, isbn = {978-0-470-85753-3}, doi = {10.1002/0470012617.ch7}, url = {http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470857536.html}, author = {Xavier Gir{\'o}-i-Nieto and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F. and Salembier, P.} } @conference {cAnton05, title = {Collaborative Network Space: Infrastructure and Learning Application}, booktitle = {IEEE Region 8 EUROCON 2005 Conference: Computer as a tool.}, year = {2005}, pages = {803{\textendash}806}, isbn = {1-4244-0050-3}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=01630054}, author = {Anton, M. and Vall-Llosera, M. and Jordi Torres and Romeu, J. and Jofre, L. and Sole, F. and Marqu{\'e}s, F. and Sabate, F. and Berenguer, J.} } @article {jFigueras05, title = {Las Mancomunidades en Espa{\~n}a}, journal = {Bolet{\'\i} de la Asociaci{\'o}n de Ge{\'o}grafos Espa{\~n}oles}, number = {39}, year = {2005}, pages = {151{\textendash}176}, issn = {0212-9426}, author = {Figueras, P. and Haas, C. and Capdevila, C. and Ver{\'o}nica Vilaplana} } @conference {cVilaplana05, title = {Region-based extraction and analysis of visual objects information}, booktitle = {Fourth International Workshop on Content-Based Multimedia Indexing, CBMI 2005}, year = {2005}, address = {Riga, Letonia}, abstract = {

In this paper, we propose a strategy to detect objects from\ still images that relies on combining two types of models: a\ perceptual and a structural model. The algorithms that are\ proposed for both types of models make use of a regionbased description of the image relying on a Binary Partition\ Tree. Perceptual models link the low-level signal description with semantic classes of limited variability. Structural\ models represent the common structure of all instances by\ decomposing the semantic object into simpler objects and\ by defining the relations between them using a DescriptionGraph.

}, isbn = {0-7803-6293-4}, author = {Ver{\'o}nica Vilaplana and Xavier Gir{\'o}-i-Nieto and Salembier, P. and Marqu{\'e}s, F.} } @conference {cVilaplana05a, title = {Support Vector Data Description Based on PCA Features for Face Detection}, booktitle = {13th European Signal Processing Conference}, year = {2005}, isbn = {0-7803-6300-0}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cSalerno04, title = {Object recognition based on Binary Partition Trees}, booktitle = {IEEE International Conference on Image Processing}, year = {2004}, pages = {929{\textendash}932}, author = {Salerno, O. and M. Pard{\`a}s and Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cVentosa03, title = {Perceptual mask estimation from watermarked images}, booktitle = {SPIE Electronic Imaging 2003}, year = {2003}, pages = {10{\textendash}17}, isbn = {?}, author = {Ventosa, S. and Elisa Sayrol and Vidal, J.} } @article {aAvrithis03, title = {Unified Access to Heterogeneous Audiovisual Archives}, journal = {Journal of universal computer science}, volume = {9}, number = {6}, year = {2003}, pages = {510{\textendash}519}, abstract = {

In this paper, an integrated information system is presented that offers enhanced search and retrieval capabilities to users of heterogeneous digital audiovisual (a/v) archives. This innovative system exploits the advances in handlings a/v content and related metadata, as introduced by MPEG-4 and worked out by MPEG-7, to offer advanced services characterized by the tri-fold semantic phrasing of the request (query), unified handling and personalized response. The proposed system is targeting the intelligent extraction of semantic information from a/v and text related data taking into account the nature of the queries that users my issue, and the context determined by user profiles. It also provides a personalization process of the response in order to provide end_users with desired information. From a technical point of view, the FAETHON system plays the role of an intermediate access server residing between the end users and multiple heterogeneous audiovisual archives organized according to the new MPEG standards.

}, issn = {0948-6968}, doi = {10.3217/jucs-009-06-0510}, url = {http://www.jucs.org/jucs_9_6}, author = {Avrithis, Y. and Stamou, G. and Wallace, M. and Marqu{\'e}s, F. and Salembier, P. and Xavier Gir{\'o}-i-Nieto and Haas, W. and Vallant, H. and Zufferey, M.} } @conference {cAvrithis03, title = {Unified access to heterogeneous audiovisual archives}, booktitle = {International Conference on Knowledge Management}, year = {2003}, pages = {1{\textendash}2}, address = {Graz, Austria}, author = {Avrithis, Y. and Stamou, G. and Wallace, M. and Marqu{\'e}s, F. and Salembier, P. and Xavier Gir{\'o}-i-Nieto and Haas, W. and Vallant, H. and Zufferey, M.} } @conference {cVidal02, title = {Color Image Watermarking Using Channel-State Knowledge}, booktitle = {SPIE Electronic Imaging 2002}, year = {2002}, pages = {214{\textendash}221}, isbn = {0-8194-4415-4}, author = {Vidal, J. and Maribel, M. and Elisa Sayrol} } @article {aMarques02, title = {Face segmentation and tracking based on connected operators and partition projection}, journal = {Pattern recognition}, volume = {35}, number = {3}, year = {2002}, pages = {601{\textendash}614}, issn = {0031-3203}, author = {Marqu{\'e}s, F. and Ver{\'o}nica Vilaplana} } @conference {cVallverdu02, title = {Graphical study of signals and systems}, booktitle = {14th annual World Conference on Educational Multimedia, Hypermedia \& Telecommunications}, year = {2002}, isbn = {0-8186-7919-0}, author = {Vallverdu, F. and Elisa Sayrol and Gasull, A. and Salavedra, J. and Moreno, A.} } @book {eSayrol02, title = {Senyals i sistemes anal{\`o}gics: una introducci{\'o} pr{\`a}ctica}, year = {2002}, isbn = {84-8301-610-9}, url = {http://www.edicionsupc.es}, author = {Elisa Sayrol and Gasull, A. and Moreno, A. and Salavedra, J. and Vallverdu, F.} } @conference {cSayrol01a, title = {Graphical Study of Signals and Systems}, booktitle = {International Conference on Acoustics, Speech and Signal Processing ICASSP{\textquoteright}01}, year = {2001}, isbn = {0-7803-1775-0}, author = {Elisa Sayrol and Gasull, A. and Moreno, A. and Salavedra, J. and Vallverdu, F.} } @conference {cVilaplana01, title = {Join detection and segmentation of human faces in color images}, booktitle = {International Conference on Augmented, Virtual Environments and 3D Imaging}, year = {2001}, pages = {347{\textendash}350}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cBescos01, title = {An open integrated system for video indexing}, booktitle = {International Workshop on Content-Based Multimedia Indexing}, year = {2001}, pages = {322{\textendash}333}, author = {Bescos, J. and Torres, L. and Menendez, J. and Vil{\`a}, J. and Cisneros, G. and Marqu{\'e}s, F. and Cabrera, J. and Mart{\'\i}nez, J.} } @article {aVilaplana01, title = {A region-based approach to face segmentation and tracking in video sequences}, journal = {Latin american applied research}, volume = {31}, number = {2}, year = {2001}, pages = {99{\textendash}106}, issn = {0327-0793}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @book {eSayrol01, title = {Senyals i sistemes anal{\`o}gics: una introducci{\'o} pr{\`a}ctica}, year = {2001}, isbn = {84-8301-510-2}, url = {www.edicionsupc.es}, author = {Elisa Sayrol and Gasull, A. and Moreno, A. and Salavedra, J. and Vallverdu, F.} } @conference {cGasull00, title = {619 - un ejemplo de dise{\~n}o del laboratorio para asignaturas con cr{\'e}ditos te{\'o}ricos y pr{\'a}cticos}, booktitle = {VIII Congreso Universitario de Innovaci{\'o}n Educativa en las Ense{\~n}anzas T{\'e}cnicas}, year = {2000}, pages = {233{\textendash}240}, isbn = {84-7585-380-3}, author = {Gasull, A. and Moreno, A. and Salavedra, J. and Elisa Sayrol and Vallverdu, F.} } @conference {cVidal00, title = {Data Hidding in Color Images using Perceptual Models}, booktitle = {COST 254 Intelligent Processing and Facilities for Communications Terminals}, year = {2000}, pages = {21{\textendash}25}, author = {Vidal, J. and Elisa Sayrol and Maribel, M.} } @conference {cMarques00, title = {A morphological approach for segmentation and tracking of human faces}, booktitle = {International Symposium on Image/Video Communications over Fixed and Mobile Networks}, year = {2000}, pages = {38{\textendash}43}, author = {Marqu{\'e}s, F. and Ver{\'o}nica Vilaplana} } @conference {cMarques00a, title = {A morphological approach for segmentation and tracking of human faces}, booktitle = {15th IAPR International Conference on Pattern Recognition}, year = {2000}, isbn = {0-7695-0750-6}, author = {Marqu{\'e}s, F. and Ver{\'o}nica Vilaplana} } @conference {cSayrol00, title = {Una Aproximaci{\'o}n experimental a las Se{\~n}ales y Sistemas Anal{\'o}gicos}, booktitle = {XV Simposium Nacional de la Uni{\'o}n Cient{\'\i}fica Internacional de Radio}, year = {2000}, pages = {329{\textendash}330}, isbn = {978-972-8865-74-0}, author = {Elisa Sayrol and Gasull, A. and Moreno, A. and Salavedra, J. and Vallverdu, F.} } @conference {cGasull99, title = {Editor gr{\'a}fico de figuras MATLAB}, booktitle = {III Congreso de Usuarios de MATLAB}, year = {1999}, pages = {219{\textendash}227}, isbn = {84-699-1358-1}, author = {Gasull, A. and Elisa Sayrol and Moreno, A. and Vallverdu, F. and Salavedra, J. and Albert Oliveras} } @conference {cTorres99, title = {Face location and recognition for video indexing in the Hypermedia project}, booktitle = {European Conference on Multimedia Applications, Services and Techniques}, year = {1999}, pages = {364{\textendash}377}, author = {Torres, L. and Marqu{\'e}s, F. and Lorente, L. and Ver{\'o}nica Vilaplana} } @inbook {aTorres99, title = {Face Location and Recognition for Video Indexing in the Hypermedia Project}, booktitle = {Lecture Notes in Computer Science}, volume = {1629}, year = {1999}, issn = {364-377}, doi = {DOI: 10.1007/3-540-48757-3_25}, author = {Torres, L. and Marqu{\'e}s, F. and Lorente, L. and Ver{\'o}nica Vilaplana} } @conference {cMarques99a, title = {Human face segmentation and tracking using connected components and partition projection}, booktitle = {1999 IEEE INternational Conference on Image Processing}, year = {1999}, isbn = {0-7803-5470-2}, author = {Marqu{\'e}s, F. and Ver{\'o}nica Vilaplana and Buxes, A.} } @conference {cMarques99, title = {A morphological approach for human face segmentation and tracking}, booktitle = {Workshop on Image Analysis for Multimedia Services}, year = {1999}, pages = {41{\textendash}44}, author = {Marqu{\'e}s, F. and Ver{\'o}nica Vilaplana and Buxes, A.} } @conference {cVidal99, title = {Non-Noticeable Information Embedding in Color Images : Marking and Detection}, booktitle = {33rd ANNUAL - 1999 International Carnahan Conference on Security Technology}, year = {1999}, pages = {293{\textendash}297}, isbn = {0-7803-5247-5}, author = {Vidal, J. and Elisa Sayrol and Cabanillas, S. and Santamaria, S.} } @conference {cSayrol99, title = {Optimum Watermark Detection in Color Images}, booktitle = {1999 IEEE International Conference on Image Processing}, year = {1999}, pages = {1{\textendash}5}, author = {Elisa Sayrol and Vidal, J. and Cabanillas, S. and Santamaria, S.} } @conference {cVilaplana99, title = {A region-based approach to face segmentation and tracking in video sequences}, booktitle = {VIII Reuni{\'o}n de Trabajo en Procesamiento de la Informaci{\'o}n y Control}, year = {1999}, pages = {345{\textendash}350}, isbn = {0-8186-8821-1}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cSayrol99a, title = {Simulaci{\'o}n digital de se{\~n}ales y sistemas anal{\'o}gicos}, booktitle = {III Congreso de Usuarios de MATLAB}, year = {1999}, pages = {67{\textendash}76}, isbn = {84-699-1358-1}, author = {Sayrol E. and Gasull, A. and Moreno, A. and Vallverdu, F. and Salavedra, J. and Albert Oliveras} } @conference {cVidal98, title = {Autentificacion digital de imagen, marcado y detecci{\'o}n {\'o}ptimos}, booktitle = {XIII Simposium Nacional de la Uni{\'o}n Cient{\'\i}fica Internacional de Radio}, year = {1998}, pages = {105{\textendash}106}, isbn = {84-89654-12-3}, author = {Vidal, J. and Elisa Sayrol and Lagunas, M.} } @conference {cVilaplana98, title = {Face segmentation using connected operators}, booktitle = {Mathematical Morphology and its applications to image and signal processing}, year = {1998}, pages = {207{\textendash}214}, isbn = {0 7923 5133 9}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F.} } @conference {cVidal98a, title = {Optimum Watermark Detection and Embedding in Digital Images}, booktitle = {1998 IEEE Second Workshop on Multimedia Signal Processing}, year = {1998}, pages = {285{\textendash}290}, isbn = {0-7803-4919-9}, author = {Vidal, J. and Elisa Sayrol} } @conference {cVilaplana98, title = {Region-based segmentation segmentation and tracking of human faces}, booktitle = {9th European Signal Processing Conference, EUSIPCO 1998}, year = {1998}, pages = {311{\textendash}314}, address = {Rhodes, Greece}, isbn = {960-7620-06-4}, author = {Ver{\'o}nica Vilaplana and Marqu{\'e}s, F. and Salembier, P. and Garrido, L.} } @conference {cGarrido97b, title = {A hierarchical technique for image sequence analysis}, booktitle = {Workshop on Image Analysis for Multimedia Application Services, WIAMIS{\textquoteright}97}, year = {1997}, pages = {13{\textendash}20}, address = {Louvain-la-Neuve, Belgium}, author = {Garrido, L. and Marqu{\'e}s, F. and M. Pard{\`a}s and Salembier, P. and Ver{\'o}nica Vilaplana} } @article {aMeyer97, title = {Morphological tools for segmentation: connected operators and watersheds}, journal = {Annales des t{\'e}lecommunications. Annals of telecommunications}, volume = {52}, number = {7-8}, year = {1997}, pages = {366{\textendash}379}, issn = {0003-4347}, author = {Meyer, F. and Albert Oliveras and Salembier, P. and Vachier, C.} } @conference {cMarques94a, title = {Hierarchical image sequence model for segmentation: application to region-based sequence coding}, booktitle = {VISUAL COMMUNICATION AND IMAGE PROCESSING}, year = {1994}, pages = {554{\textendash}563}, author = {Marqu{\'e}s, F. and Gasull, A. and Vera, V.} } @conference {cMarques94b, title = {Recursive image sequence segmentation by hierarchical models}, booktitle = {12th IAPR International Conference on Pattern Recognition}, year = {1994}, pages = {523{\textendash}525}, isbn = {0-8186-6265-4}, author = {Marqu{\'e}s, F. and Vera, V. and Gasull, A.} } @conference {cMarques94, title = {Top-down 3d image sequence segmentation technique controlled by morphological}, booktitle = {EUSIPCO-94.}, year = {1994}, pages = {415{\textendash}418}, author = {Marqu{\'e}s, F. and Vera, V. and Gasull, A.} } @conference {cGasull92c, title = {Coagulation time detection by means of a real-time image processing}, booktitle = {14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society}, year = {1992}, pages = {1948{\textendash}1949}, author = {Gasull, A. and Vallverdu, F. and Marqu{\'e}s, F.} } @conference {cOliveras91, title = {Tou - Brazo Robot Asistencial: Control Verbal}, booktitle = {2{\textordmasculine} Congreso de la Asociaci{\'o}n Espa{\~n}ola de Rob{\'o}tica}, year = {1991}, pages = {93{\textendash}100}, isbn = {0-7803-7043-0}, author = {Albert Oliveras and Fuertes, J. and Vill{\`a}, R.} } @conference {cGasull89a, title = {Automated left ventricular contour extraction and volume calculation form echocardiographic images}, booktitle = {Ultrasonics International 89}, year = {1989}, pages = {1{\textendash}4}, isbn = {SN.}, author = {Gasull, A. and Alquezar, R. and Torres, L. and Sallent, S. and Marqu{\'e}s, F. and Vidal, J. and Sangr{\'a}, E.} } @conference {cGasull89, title = {Automatic left ventricular contour for volume calculation}, booktitle = {Ultrasonics International 89}, year = {1989}, pages = {123{\textendash}126}, isbn = {SN.}, author = {Gasull, A. and Vazquez, G.} } @conference {cVazquez89, title = {Constant variance transversal filtering for adaptive channel equalization}, booktitle = {INTERNATIONAL CONFERENCE ON SONAR SIGNAL PROCESSING}, year = {1989}, pages = {212{\textendash}215}, isbn = {0-7923-9733-9}, author = {Vazquez, G. and Gasull, A. and Sanchez, J. and Lagunas, M.} } @conference {cGasull88, title = {Detecci{\'o}n autom{\'a}tica de contornos en im{\'a}genes ecogr{\'a}ficas}, booktitle = {III Simposium Nacional de Reconocimiento de Formas y An{\'a}lisis de Im{\'a}genes}, year = {1988}, pages = {1{\textendash}4}, isbn = {?}, author = {Gasull, A. and Marqu{\'e}s, F. and Sallent, S. and Torres, L. and Vidal, J.} }