Python Opencv实践 - 图像混合

import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt

img_dog = cv.imread("../SampleImages/pomeranian.png", cv.IMREAD_COLOR)
plt.imshow(img_dog[:,:,::-1])

img_water = cv.imread("../SampleImages/waterdrop.jpg", cv.IMREAD_COLOR)
plt.imshow(img_water[:,:,::-1])

#相同大小尺寸的两幅图像混合
#g(x) = (1 - a)h(x) + af(x), a为0-1之间的值，h(x),f(x)表示两幅图像的像素值
#cv.addWeighted(src1, alpha, src2, beta, gamma, dst=None, dtype=None)
#参考资料：https://blog.csdn.net/LaoYuanPython/article/details/109143281
img_blended = cv.addWeighted(img_dog, 0.75, img_water, 0.25, 0)
plt.imshow(img_blended[:,:,::-1])

# 不同尺寸之间的两幅图像混合,自定义一个函数
# addWeightedSmallImgToLargeImg(largeImg,alpha,smallImg,beta,gamma=0.0,regionTopLeftPos=(0,0))
# 前五个参数和addWeighted一样，多了一个regionTopLeftPos参数用于指定小图在大图中左上角的位置
def addWeightedSmallImgToLargeImg(largeImg,alpha,smallImg,beta,gamma=0.0,regionTopLeftPos=(0,0)):
    srcW, srcH = largeImg.shape[1::-1]
    refW, refH = smallImg.shape[1::-1]
    x,y =  regionTopLeftPos
    if (refW>srcW) or (refH>srcH):
        #raise ValueError("img2's size must less than or equal to img1")
        raise ValueError(f"img2's size {smallImg.shape[1::-1]} must less than or equal to img1's size {largeImg.shape[1::-1]}")
    else:
        if (x+refW)>srcW:
            x = srcW-refW
        if (y+refH)>srcH:
            y = srcH-refH
        destImg = np.array(largeImg)
        tmpSrcImg = destImg[y:y+refH,x:x+refW]
        tmpImg = cv.addWeighted(tmpSrcImg, alpha, smallImg, beta,gamma)
        destImg[y:y + refH, x:x + refW] = tmpImg
        return destImg

img_cat = cv.imread("../SampleImages/cat.jpg", cv.IMREAD_COLOR)
plt.imshow(img_cat[:,:,::-1])

img_blended = addWeightedSmallImgToLargeImg(img_cat, 0.65, img_dog, 0.35, 0, (100,300))
plt.imshow(img_blended[:,:,::-1])