Abstract
Video segmentation is fundamental to a number of applications related to video retrieval and analysis. Shot change detection is the initial step of video segmentation and indexing. There are two basic types of shot changes. One is the abrupt change or cut, and the other is the gradual shot transition. The smooth variations of the video feature values in a gradual transition produced by the editing effects are often confused with those caused by camera or object motions. To overcome this difficulty, it is reasonable to estimate the motions and suppress the disturbance caused by them. In this thesis, we explore the possibility to exploit motion and illumination estimation in a video sequence to detect both abrupt and gradual shot changes. A generalized optical flow constraint that includes an illumination parameter to model local illumination changes is employed in the motion and illumination estimation. An iterative process is used to refine the generalized optical flow constraints step by step. A robust measure that is the likelihood ratio of the corresponding motion-compensated blocks in the consecutive frames is used for detecting abrupt changes. For the detection of gradual shot transitions, we compute the average monotony of intensity variations on the stable pixels in the images in a twin-comparison framework. We test the proposed algorithm on a number of video sequences in TREC 2001 and compare the detection results with the best results reported in the TREC 2001 benchmark. The comparisons indicate that the proposed shot change detection algorithm is competitive against the best existing algorithms.