Conditional random field based image and video content analysis

Abstract

Image and video content analysis is an interesting, meaningful and challenging topic. In recent years much of the research effort in the multimedia field focuses on indexing and retrieval. Semantic gap between low-level features and high-level content is a bottleneck in most systems. To bridge the semantic gap, new content analysis models need to be developed. In this thesis, algorithms based on a relatively new graphical model, called the conditional random field (CRF) model, are developed for two closely-related problems in content analysis: image labeling and video content analysis. The CRF model can represent spatial interactions in image labeling and temporal interactions in video content analysis. New feature functions are designed to better represent the feature distributions. The mixture feature functions are used in image labeling for databases with nature images, and the independent component analysis (ICA) mixture function is applied in sports video content analysis. The spatial dependence of image parts and the temporal dependence of video frames can be explored by the CRF model more effectively using new feature functions. For image labeling with large databases, the content-based image retrieval method is combined with the CRF image labeling model successfully.