使用OpenCV库中的Canny边缘检测函数进行预处理，然后使用霍夫变换检测直线，进而确定矩形的边缘。

示例代码：

import cv2

读取图像

img = cv2.imread('image.jpg')

灰度化

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

Canny边缘检测

edges = cv2.Canny(gray, 50, 150, apertureSize=3)

霍夫变换检测直线

lines = cv2.HoughLines(edges, 1, np.pi/180, 200)

转换直线为矩形

for line in lines: rho, theta = line[0] a = np.cos(theta) b = np.sin(theta) x0 = arho y0 = brho x1 = int(x0 + 1000*(-b)) y1 = int(y0 + 1000*(a)) x2 = int(x0 - 1000*(-b)) y2 = int(y0 - 1000*(a)) cv2.rectangle(img, (x1, y1), (x2, y2), (0, 255, 0), 2)

显示结果

cv2.imshow('result', img) cv2.waitKey(0) cv2.destroyAllWindows()