实现“基于互信息量”进行关键帧提取的具体算法，该算法以帧间的互信息量来衡量两帧图像内容的相似性，可以对具体镜头按其特点自动提取出一或多个关键帧。-To achieve " Based on mutual information" to a specific key-fr a me extraction algorithm in order to fr a mes to measure the two mutual information similarity of image