中文说明：使用五帧进行差分计算，用第五帧与前四帧进行相减，然后将得到的结果进行与操作，运行时间比三帧差的运行时间快一点，可以作为帧差法的改进算法。
English Description：
Five frames are used for difference calculation, the fifth frame is subtracted from the first four frames, and then the results are processed and operated. The running time is faster than that of three frames difference, which can be used as an improved algorithm of frame difference method.