Compute variance of image

Question

I want to compute a variance of laplacian of an image without using opencv since opencv is quite huge. So, I want to use any other library that has smaller size.

Here is my current code. It works perfectly but using opencv-python-headless:

import cv2

image = cv2.imread("images/test.png")
image_gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

laplacian = cv2.Laplacian(image_gray, cv2.CV_64F).var()
print(laplacian)

How can I get the same result (same laplacian value) using any other library/libraries that has smaller size?

Answer 1

You might consider using scipy instead with its laplacian function.

from scipy import ndimage #To compute the laplacian
import imageio #To load the image as a numpy array
import numpy as np #To convert it to gray

#A function to convert your rgb image to gray
convert_to_gray = lambda rgb : np.dot(rgb[... , :3] , [0.299 , 0.587, 0.114]) 

image = imageio.imread("images/test.png")
image_gray = convert_to_gray(image)

laplacian = ndimage.laplace(image_gray).var()
print(laplacian)