VisualGREP : a systematic method to compare and retrieve video sequences

In this paper, we consider the problem of similarity between video sequences. Three basic questions are raised and (partially) answered. Firstly, at what temporal duration can video sequences be compared? The frame, shot, scene and video levels are identified. Secondly, given some image or video feature, what are the requirements on its distance measure and how can it be "easily" transformed into the visual similarity desired by the inquirer? Thirdly, how can video sequences be compared at different levels? A general approach based on either a set or sequence representation with variable degrees of aggregation is proposed and applied recursively over the different levels of temporal resolution: It allows the inquirer to fully control the importance of temporal ordering and duration. The general approach is illustrated by introducing and discussing some of the many possible image and video features. Promising experimental results are presented