根据平均值法获得背景图片我要分享

中文说明：

首先从视频中提取100张图片，用其中五十张图片根据平均值法获得背景图片，然后做差，二值化，提取目标。

English Description：

First, extract 100 pictures from the video, use 50 of them to obtain the background picture according to the average method, and then make difference, binarization and extract the target