SIFT特征提取的实现和演示，VC6.0下实现。-SIFT feature extraction implementation and demonstration, VC6.0 achieve.

用于图像拷贝检测的图像匹配，提取图像的SIFT特征点，构成图像的特征。-For image copy detection of image matching, image SIFT feature point extraction, and then sift feature point the image characteristics