x=np.uint8([250])
y=np.uint8([10])
print(cv2.add(x,y))#250+10=260>=255
#结果为[[255]]
print (x+y)#250+10=260%255=4
#结果为[4]

dst = cv2.addWeighted(img1,0.7,img2,0.3,0)

mask_inv = cv2.bitwise_not(mask)
img1_bg = cv2.bitwise_and(roi,roi,mask=mask)

import cv2
import numpy as np
#图像加法
x=np.uint8([250])
y=np.uint8([10])
print(cv2.add(x,y))#250+10=260>=255#.两幅图像的大小，类型必须一致，或者第二个图像可以是一个简单的标量值。
#结果为[[255]]
print (x+y)#250+10=260%255=4
#结果为[4]#图像混合
img1=cv2.imread('test.jpg')
logo = cv2.imread('logo.jpg')
img2=cv2.resize(logo, (50, 50))#dst = cv2.addWeighted(img1,0.7,img2,0.3,0)#.两幅图像的大小，类型必须一致，或者第二个图像可以是一个简单的标量值。#cv2.imshow('dst',dst)
#cv2.waitKey(0)
#cv2.destroyAllWindows()#按位运算
# 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 inverse mask also
img2gray = cv2.cvtColor(img2,cv2.COLOR_BGR2GRAY)#灰度化
ret,mask = cv2.threshold(img2gray,175,255,cv2.THRESH_BINARY)#二值化
mask_inv = cv2.bitwise_not(mask)#取非# Now black-out the area of logo in ROI
#取ROI中与mask中不为零的值对应的像素的值，让其值为0 。
#注意这里必须有mask=mask或者mask=mask_inv，其中mask=不能忽略
img1_bg = cv2.bitwise_and(roi,roi,mask=mask)
#取roi中与mask_inv中不为零的值对应的像素的值，其他值为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)
cv2.imshow('dst', dst)
img1[0:rows,0:cols] =dstcv2.imshow('res',img1)
cv2.waitKey(0)
cv2.destroyAllWindows()