关键词: 背景提取, 背景更新, 帧间差分, 背景差分

Abstract: To extract good background image from complex scenes，this paper proposes an algorithm of background extraction based on both frame-difference and background subtraction，and using multi-level adaptive background update strategy，it can avoid the effect of new objects to the background and eliminate the ghosts caused by the move-away of background objects.Experiment shows it is a practical method that is robust under lighting variations，fast in speed，satisfactory in updating performance.

Key words: background extraction, background updating, frame-difference, background subtraction