image_blending.py

"""
to use image pyramids to blend images:
1)load the 2 images
2) find gaussian pyramids of these 2 images
3)from gaussian pyramids, find their lepracian pyramids
4) now join each left part of apple to right part of orange using in level of lapracian pyramids
5)finally from this join image, reconstruct the original image.
"""

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:])) #to join half of apple image to orange image, but its just pure joining

# 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()