中文说明：检测当前图像和背景图像中对应像素点的差异，如果差值大于一定阈值，则判定该像素为前景运动目标。 前提假设 在背景模型提取阶段，运动目标在场景区域中运动，不会长时间停留在某一位置 视频流中某一像素
English Description：
Detect the difference between the current image and the background image, if the difference is greater than a certain threshold, then determine the pixel as the moving target.The premise hypothesis is that the moving target is in the scene area, and the object is not to stay in a certain position for a long time.Video stream in a pixel only in the foreground object and its brightness value of a big change took place, within a period of time, brightness value mainly concentrated in a very small area, can be used within the region average value as the background value. Specific implementation process: in the YUV color space, the range of Y value is 0~255, and the range is divided into several ranges [0, T][T, 2T]... [Nt, 255], n=255/T, for each pixel, the number of times within each interval of the brightness values of the time. Find the interval that occurs most frequently, and the average value of all values within the interval is the luminance value of the background model at that poi