CODEWITHSUNDEEP
pythonimageopencv
Amanda
Amanda

Reputation: 2143

Blending multiple images with OpenCV

What is the way to blend multiple images with OpenCV using python? I came across the following snippet:

img = cv2.addWeighted(mountain, 0.3, dog, 0.7, 0)

on https://docs.opencv.org/3.4/d5/dc4/tutorial_adding_images.html

that shows a way to blend 2 images mountain and dog. What if I want to blend more than 2 images? How could I do this?

Upvotes: 3

Views: 17990

Answers (3)

stackoverflowuser2010
stackoverflowuser2010

Reputation: 40859

Here is Python code to blend multiple images in a list. I used the basic formulation from Shamsheer's answer.

First, let's get three images.

import numpy as np
import cv2
import matplotlib.pyplot as plt
import matplotlib.image as mpimg

dim = (425, 425)

apple = mpimg.imread('apple.jpg')
apple = cv2.resize(apple, dim)

banana = mpimg.imread('banana.jpg')
banana = cv2.resize(banana, dim)

orange = mpimg.imread('orange.jpg')
orange = cv2.resize(orange, dim)

_ = plt.imshow(apple)
_ = plt.show()

_ = plt.imshow(banana)
_ = plt.show()

_ = plt.imshow(orange)
_ = plt.show()

Here are the images:

enter image description here

enter image description here

enter image description here

Now let's blend them together equally. Since there are three images, the fraction of each image's contribution to the final output is 0.333.

def blend(list_images): # Blend images equally.

    equal_fraction = 1.0 / (len(list_images))

    output = np.zeros_like(list_images[0])

    for img in list_images:
        output = output + img * equal_fraction

    output = output.astype(np.uint8)
    return output

list_images = [apple, banana, orange]
output = blend(list_images)

_ = plt.imshow(output)

And here is the result:

enter image description here

Upvotes: 2

Shamsheer
Shamsheer

Reputation: 744

Try This:

blendedImage = weight_1 * image_1 + weight_2 * image_2 + ... + weight_n * image_n

Upvotes: 7

AnsFourtyTwo
AnsFourtyTwo

Reputation: 2518

You can blend all of your images by blending according to follwoing sequence:

  1. Blend the first two images
  2. Take the result and blend it with the next image
  3. and so forth
for idx, img in enumerate(imgs):
    if idx == 1:
        first_img = img
        continue
    else:
        second_img = img
        first_img = cv2.addWeighted(first_img, 0.5, second_img, 0.5, 0)

You might have a problem with the weights of each image, but this is another issues. To achieve an equal weigth for all images you can use the index to calculate the appropriate portion:

for idx, img in enumerate(imgs):
    if idx == 1:
        first_img = img
        continue
    else:
        second_img = img
        second_weight = 1/(idx+1)
        first_weight = 1 - second_weight
        first_img = cv2.addWeighted(first_img, first_weight, second_img, second_weight, 0)

Upvotes: 4

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