背景提取，迭代法(Surendra算法）；即采用帧差的方法，一帧图像减去前一帧图像，即可以对比得到图像中变化（移动）的区域，扣除移动的区域，即得到不动的背景。采用多帧图像迭代的方法，得到更加准确的背景。-Background extraction, iterative method (Surendra algorithm)　frame difference method is used, an image by subtracting the previous frame, which can receive the image contrast change (movement) of the area, less the area of ​ ​ movement, that is obtained immovable background. Multi-frame image iteration method, to be more accurate background.