用pillow和 opencv做透明通道的两图混全(blend)

from PIL import Image as image 
 
foreground = image.open("donkey.png")
background = image.open( "back.jpg" )
alpha = image.open( "donkeyAlpha.png" )
outImage = image.composite( foreground, background, alpha )
outImage.save( "./pilblend.png" )

import cv2
foreground = cv2.imread("donkey.png")
background = cv2.imread("back.jpg")
alpha = cv2.imread("donkeyAlpha.png")
# Convert uint8 to float
foreground = foreground.astype(float)
background = background.astype(float)
# Normalize the alpha mask to keep intensity between 0 and 1
alpha = alpha.astype(float)/255
foreground = cv2.multiply(alpha, foreground)
background = cv2.multiply(1.0 - alpha, background)
outImage = cv2.add(foreground, background)
cv2.imwrite( "./cv2blend.png"  ,outImage )