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 pattern classification, matching and tracking, visual surveillance, image content anaysis, and so on.