An efficient graphical shot verifier incorporating visual rhythm

Recent publications regarding video shot change detection algorithms show that abrupt shot changes are detected fairly well. However, gradual shot changes, including wipes and dissolves, are often missed or falsely detected. A robust shot change detection system, therefore, must include a shot verification step to further enhance the overall system performance. In this paper, we introduce the concept of a visual rhythm, an abstraction of the video. A visual rhythm is a single image, a sub-sampled version of a full video in which the sampling is performed in a pre-determined and in a systematic fashion. It is basically a representation of the video which includes the overall content of the video, but most importantly, the visual rhythm contains patterns or visual features that allow the viewer/operator to distinguish and classify many different types of video effects (edits and otherwise): cuts, wipes, dissolves, fades, camera motions, object motions, flashlights, zooms, etc. The different video effects manifest themselves as different patterns on the visual rhythm. Using the visual rhythm, it becomes possible, without sequentially playing the entire video, to find false positive shots as well as undetected shots. Thus, inclusion of the visual rhythm in the shot verification process will aid the operator to verify detected shots as well as to find undetected shots fast and efficiently. For this purpose, we have developed a new tool, a shot verifier that includes the visual rhythm. The usefulness of the visual rhythm during the shot verification process is presented.