https://www.cnblogs.com/my-love-is-python/p/10414135.html
sift一些函数及用法
detector = cv2.xfeatures2d.SIFT_create()
keyPoints = detector.detect(img,None)
imgWithPoint = cv2.drawKeyPoints( img,keyPoints,img )
原文：https://www.cnblogs.com/ChevisZhang/p/13182808.html