Laplacian pyramid

# -*- coding: utf-8 -*-
"""
Created on Fri Jun 24 14:24:07 2022
 
@author: https://theailearner.com/tag/laplacian-pyramid-opencv/
"""
import cv2
from matplotlib import pyplot as plt
 
def showimage(myimage, figsize=[10,10]):
    if (myimage.ndim>2):  #This only applies to RGB or RGBA images (e.g. not to Black and White images)
        myimage = myimage[:,:,::-1] #OpenCV follows BGR order, while matplotlib likely follows RGB order
 
    fig, ax = plt.subplots(figsize=figsize)
    ax.imshow(myimage, cmap = 'gray', interpolation = 'bicubic')
    plt.xticks([]), plt.yticks([])  # to hide tick values on X and Y axis
    plt.show()
 
# Load the grayscale image
img = cv2.imread('lena.jpg',0)
lower = img.copy()
 
# Create a Gaussian Pyramid
gaussian_pyr = [lower]
for i in range(5):
    lower = cv2.pyrDown(lower)
    gaussian_pyr.append(lower)
 
# Last level of Gaussian remains same in Laplacian
laplacian_top = gaussian_pyr[-1]
 
# Create a Laplacian Pyramid
laplacian_pyr = [laplacian_top]
for i in range(5,0,-1):
    size = (gaussian_pyr[i - 1].shape[1], gaussian_pyr[i - 1].shape[0])
    print(size)
    gaussian_expanded = cv2.pyrUp(gaussian_pyr[i], dstsize=size)
    laplacian = cv2.subtract(gaussian_pyr[i-1]*10, gaussian_expanded)
    laplacian_pyr.append(laplacian)
    showimage(laplacian)