cv2.bitwise_and的應用,

import cv2
import numpy as np

Load two images

img1 = cv2.imread('messi.png')
img2 = cv2.imread('logo.png')

I want to put logo on top-left corner, So I create a ROI

rows,cols,channels = img2.shape
roi = img1[0:rows, 0:cols ]

Now create a mask of logo and create its invers mask also

img2gray = cv2.cvtColor(img2,cv2.COLOR_BGR2GRAY)
ret, mask = cv2.threshold(img2gray, 240, 255, cv2.THRESH_BINARY) # mask 背景依然是白色，彩色logo是黑色
mask_inv = cv2.bitwise_not(mask)

Now black-out the area of logo in ROI

img1_bg = cv2.bitwise_and(roi,roi,mask = mask) #背景變成白，2背景部分進行操作，logo部分變黑，為0，這部分的值變為0

Take only region of logo from logo image.

img2_fg = cv2.bitwise_and(img2,img2,mask = mask_inv)

Put logo in ROI and modify the main image

dst = cv2.add(img1_bg,img2_fg)
img1[0:rows, 0:cols ] = dst

cv2.imshow('res',img1)

cv2.waitKey(0)
cv2.destroyAllWindows()