In order to solve the problem that a big breaking in object causes the background to change its illumination and make detection results invalid, three frame difference is used to detect moving object. 首先给出三帧差运动对象检测算法,同时利用像素的亮度分量和色度分量避免由于大尺寸对象闯入引起图像背景像素变化造成运动对象检测的失败。