COMP9517 lab2 SIFT

https://www.cnblogs.com/my-love-is-python/p/10414135.html

Task1:

　　sift一些函数及用法

　　detector = cv2.xfeatures2d.SIFT_create()

　　keyPoints = detector.detect(img,None)

　　imgWithPoint = cv2.drawKeyPoints( img,keyPoints,img )

　　https://docs.opencv.org/3.4.9/d5/d3c/classcv_1_1xfeatures2d_1_1SIFT.html  　

contrastThreshold

The contrast threshold used to filter out weak features in semi-uniform (low-contrast) regions. The larger the threshold, the less features are produced by the detector.

Task2:

　　https://www.tutorialkart.com/opencv/python/opencv-python-resize-image/

　　cv2.resize()

　　https://docs.opencv.org/master/dc/dc3/tutorial_py_matcher.html

　　bf = cv2.BFMatcher()

　　Sift 感觉都是用的bf.knnMatch()

Task3:

 　　1) 旋转的中心是  image[1]//2, image[0]//2 需要颠倒过来， 旋转的度数，顺时针为负

　　center = get_img_center(img)
　　rotated_img = rotate(img,center[1],center[0],-60)