Python OpenCV使用轮廓线查找正方形

import cv2
import numpy as np

image = cv2.imread('image.jpg')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray, (5, 5), 0)

edges = cv2.Canny(blur, 50, 150)

contours, _ = cv2.findContours(edges, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)

squares = []
for contour in contours:
    perimeter = cv2.arcLength(contour, True)
    approx = cv2.approxPolyDP(contour, 0.04 * perimeter, True)
    if len(approx) == 4:
        squares.append(approx)

cv2.drawContours(image, squares, -1, (0, 255, 0), 3)