Python 19.opencv 形状匹配，输出相似率

import cv2
import numpy as np

img1 = cv2.imread('star1.PNG', 0)
img2 = cv2.imread('star2.PNG', 0)
img3 = cv2.imread('star3.PNG', 0)

ret, thresh1 = cv2.threshold(img1, 127, 255, 0)
ret, thresh2 = cv2.threshold(img2, 127, 255, 0)
ret, thresh3 = cv2.threshold(img3, 127, 255, 0)

contours, hierarchy = cv2.findContours(thresh1, 2, 1)
cnt1 = contours[0]
contours, hierarchy = cv2.findContours(thresh2, 2, 1)
cnt2 = contours[0]
contours, hierarchy = cv2.findContours(thresh3, 2, 1)
cnt3 = contours[0]

# 越相近，数越小，轮廓大小最好相当
ret1 = cv2.matchShapes(cnt1, cnt2, 1, 0.0)
ret2 = cv2.matchShapes(cnt1, cnt3, 1, 0.0)
ret3 = cv2.matchShapes(cnt1, cnt1, 1, 0.0)

print(ret1)
print(ret2)
print(ret3)