Measure similarity between images using Python-OpenCV

Prerequisites: Python OpenCV

Suppose we have two data images and a test image. Let’s find out which data image is more similar to the test image using python and OpenCV library in Python.

Let’s first load the image and find out the histogram of images.

Importing library

import cv2

Importing image data

image = cv2.imread('test.jpg')

Converting to gray image

gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

Finding Histogram

histogram = cv2.calcHist([gray_image], [0], 
                              None, [256], [0, 256])


Images used:








import cv2
# test image
image = cv2.imread('cat.jpg')
gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
histogram = cv2.calcHist([gray_image], [0], 
                         None, [256], [0, 256])
# data1 image
image = cv2.imread('cat.jpeg')
gray_image1 = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
histogram1 = cv2.calcHist([gray_image1], [0], 
                          None, [256], [0, 256])
# data2 image
image = cv2.imread('food.jpeg')
gray_image2 = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
histogram2 = cv2.calcHist([gray_image2], [0], 
                          None, [256], [0, 256])
c1, c2 = 0, 0
# Euclidean Distace between data1 and test
i = 0
while i<len(histogram) and i<len(histogram1):
    i+= 1
c1 = c1**(1 / 2)
# Euclidean Distace between data2 and test
i = 0
while i<len(histogram) and i<len(histogram2):
    i+= 1
c2 = c2**(1 / 2)
    print("data1.jpg is more similar to test.jpg as compare to data2.jpg")
    print("data2.jpg is more similar to test.jpg as compare to data1.jpg")


Output :

data1.jpg is more similar to test.jpg as compare to data2.jpg

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :

Be the First to upvote.

Please write to us at to report any issue with the above content.