根据David Lowe的SIFT编写了一个利用其进行特征点提取和匹配的程序，由于该库只支持PGM，所以自己又写了包括jpg等图片转为PGM的子函数-According to David Lowe' s SIFT to write a use of the feature point extraction and matching procedures, the library only supports PGM himself wrote including jpg and other