1. 读取两张图片并转换为灰度图像：

import cv2

img1 = cv2.imread('image1.jpg')
img1_gray = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)

img2 = cv2.imread('image2.jpg')
img2_gray = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)

2. 通过减法计算两张图片的差异：

diff = cv2.absdiff(img1_gray, img2_gray)

3. 使用阈值处理来得到二值图像：

threshold = 30
_, thresh = cv2.threshold(diff, threshold, 255, cv2.THRESH_BINARY)

4. 计算轮廓并画出差异区域：

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

for contour in contours:
    (x, y, w, h) = cv2.boundingRect(contour)
    cv2.rectangle(img1, (x, y), (x + w, y + h), (0, 0, 255), 2)

5. 显示结果：

cv2.imshow('result', img1)
cv2.waitKey(0)