In recent years, the use of multimedia content has experienced an exponential growth. In this context, the need of new image/video sequence representation is becoming a necessity for many applications. This paper deals with the structuring of video shots in terms of various foreground key-regions and a background mosaic. Each key-region represents different foreground objects that appear through the entire sequence in a similar manner the mosaic image represents the background information of the complete sequence. We focus on the interest of morphological tools such as connected operators or watersheds to perform the shot analysis and the computation of the key-regions and the mosaic. It will be shown that morphological tools are particularly attractive to improve the robustness of the various steps of the algorithm.