带有alpha通道的模板匹配（局限性：只能匹配从图中截取的某一部分）

gistfile1.py

import cv2
import numpy as np


def main():
    # 加载原始RGB图像
    img_rgb = cv2.imread("test.png", cv2.IMREAD_UNCHANGED)

    # 加载将要搜索的图像模板
    template = cv2.imread('logo.png', cv2.IMREAD_UNCHANGED)
    # 记录图像模板的尺寸
    h = template.shape[0]
    w = template.shape[1]

    channels = cv2.split(template)

    mask = np.array(channels[3])
    transparent_mask = cv2.merge([mask, mask, mask, mask])

    res = cv2.matchTemplate(img_rgb, template, cv2.TM_CCORR_NORMED,
                            mask=transparent_mask)

    min_val, max_val, min_loc, max_loc = cv2.minMaxLoc(res)
    print(min_val)
    top_left = min_loc
    bottom_right = (top_left[0] + w, top_left[1] + h)
    cv2.rectangle(img_rgb, top_left, bottom_right, (7, 249, 151), 2)

    cv2.imshow('Detected', img_rgb)
    cv2.waitKey(0)
    cv2.destroyAllWindows()


if __name__ == '__main__':
    main()