Image Blending

Steps Image Blending:  

1.       Load the two images of apple and orange

2.       Find the Gaussian pyramids for apple and orange(in this particular example, number of lavels is 6).

3.       From Gaussian pyramids, find their laplacian pyramids.

4.       Now join the left half of apple and right half of orange in each levels of laplacian pyramids.

5.       Finally from this joint image pyramids, reconstruct the original image.

Note: When we apply the Gaussian and laplacian pyramid the line between apple and orange is not visible.

import cv2
import numpy as np
apple = cv2.imread('apple.jpg')
orange = cv2.imread('orange.jpg')
print(apple.shape)
print(orange.shape)
apple_orange = np.hstack((apple[:, :256], orange[:, 256:]))
#generate Gaussian pyramid for apple
apple_copy = apple.copy()
gp_apple = [apple_copy]
for i in range(6):
    apple_copy = cv2.pyrDown(apple_copy)
    gp_apple.append(apple_copy)

#generate Gaussian pyramid for orange
orange_copy = orange.copy()
gp_orange = [orange_copy]
for i in range(6):
    orange_copy = cv2.pyrDown(orange_copy)
    gp_orange.append(orange_copy)

#generate Laplacian pyramid for apple
apple_copy = gp_apple[5]
lp_apple = [apple_copy]
for i in range(5, 0, -1):
    gaussian_expanded = cv2.pyrUp(gp_apple[i])
    laplacian = cv2.subtract(gp_apple[i-1], gaussian_expanded)
    lp_apple.append(laplacian)

#generate Laplacian pyramid for orange
orange_copy = gp_orange[5]
lp_orange = [orange_copy]
for i in range(5, 0, -1):
    gaussian_expanded = cv2.pyrUp(gp_orange[i])
    laplacian = cv2.subtract(gp_orange[i-1], gaussian_expanded)
    lp_orange.append(laplacian)

#now add left and right halves of images in each level
apple_orange_pyramid = []
n = 0
for apple_lap, orange_lap in zip(lp_apple, lp_orange):
    n += 1
    cols, rows, ch = apple_lap.shape
    laplacian = np.hstack((apple_lap[:, 0:int(cols/2)], orange_lap[:, int(cols/2):]))
    apple_orange_pyramid.append(laplacian)

#now reconstruct
apple_orange_reconstruct = apple_orange_pyramid[0]
for i in range(1, 6):
    apple_orange_reconstruct = cv2.pyrUp(apple_orange_reconstruct)
    apple_orange_reconstruct = cv2.add(apple_orange_pyramid[i], apple_orange_reconstruct)

cv2.imshow("apple", apple)
cv2.imshow("orange", orange)
cv2.imshow("apple_orange", apple_orange)
cv2.imshow("apple_orange_reconstruct", apple_orange_reconstruct)
cv2.waitKey(0)
cv2.destroyAllWindows()