opencv的sift算法

import cv2
import matplotlib.pyplot as plt

chess = cv2.imread('./chess.png')

gray = cv2.cvtColor(chess, cv2.COLOR_BGR2GRAY)

#创建sift对象
#需要opencv-contrib-python
sift = cv2.xfeatures2d.SIFT_create()
#进行检测

kp = sift.detect(gray)
#kp是一个列表
#绘制关键点（gray是对谁画，kp是画的点，chess是画的地方）
cv2.drawKeypoints(gray, kp, chess)
cv2.imshow('img', chess)
           
cv2.waitKey(0)
cv2.destroyAllWindows()