My main research directions include computer vision, pattern recognition, and image/signal processing. I have worked on some fundamental problems and contributed to the frontier knowledge in these areas. Some of the techniques have been used to conduct advanced multimedia applications. In recent years, I particularly focus on researches of computer vision-based technologies. The techniques developed are benefit to applications such as visual surveillance, human-computer interaction, and image/video analysis. The research topics include pedestrian detection, articulated hand tracking, motion segmentation, salient feature matching, 3D virtual exhibition, lighting normalization, near-duplicate image detection, and so on.