从avi格式的视频中提取bmp格式的关键帧，以达到压缩空间的效果。-Avi video format from bmp format to extract the key frames to achieve the effect of compressed space.

基于matlab编写的提取交通视频关键帧的小程序，设置了虚拟区域，便于选中关键帧进行处理。-Keyframe matlab prepared extract traffic video-based program, set the virtual area, easy to select the key frames for processing.