使用对称帧差法提取运动模板，后结合背景帧差提取运动目标，二者结合进行逻辑运算，得到最终的运动目标；内部含有一个单独的函数，用于背景重构-Extracted using the symmetric difference motion template frame, combined with the background of the frame difference after the extraction of moving objects, a combination of both logic operations, the final of the moving object　inside with a separate function, for background reconstruction