由图像的颜色直方图求取相应的区域颜色熵，利用该信息判断出两幅图像间的相似度，可将其利用到诸如镜头检测之类的场合中-Use color histogram to calculate corresponding regional color entropy, use this information to determine the similarity between two images,which can be used to detect the occasions such as shot

SIFT源代码，检测两幅图像的相似度。详细检测过程，在原文中有备注(SIFT source code, to detect the similarity of two images)