孟德宇老师的低秩分解代码，对动态变化的视频帧提取它的低秩背景，同时得到它的稀疏部分。利用混合高斯对误差进行建模(Teacher Meng Deyu's low rank decomposition code extracts the low rank background of the dynamic video fr a me and obtains the sparse part of it. The error is modeled by mixed Gauss)