基于OPENCV的SIFT特征提取与匹配算法。包含完整的从图像高斯金字塔、DOG、空间极值点提取、关键点描述、KDtree匹配等关键步骤的全部函数实现，对全面深入理解Lowe的SIFT算法有莫大帮助。-OPENCV based SIFT feature extraction and matching algorithms. Extracted from the image Gaussian pyramid, DOG, space extremum point contains a complet