Sample code transform image using LUT

import cv2
import numpy as np

def lookup_table_transform(image, table):
    if len(table) != 256:
        raise ValueError("Lookup table must have exactly 256 values")
    
    lut = np.array(table, dtype=np.uint8)
    
    if len(image.shape) == 2:
        return cv2.LUT(image, lut)
    
    elif len(image.shape) == 3:
        result = image.copy()
        for i in range(image.shape[2]):
            result[:, :, i] = cv2.LUT(image[:, :, i], lut)
        return result
    
    else:
        raise ValueError("Unsupported image format")


def main():
    
    output_image = 'output.png'
    image = cv2.imread('image.png',0)
    
    table = np.arange(256)
    table[0:100] = 0
    table[100:200] = 100
    table[200:255] = 200
    table[255] = 255
    transformed_image = lookup_table_transform(image, table)

    cv2.imwrite(output_image, transformed_image)
    
    final_image = np.hstack((image, transformed_image))
    cv2.imshow('Final Image', final_image)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

if __name__ == "__main__":
    main()