Image Quantisation

quantisation.py

import numpy as np
from PIL import Image

IMG_PATH = "./assets/water.jpeg"


def quantise(pixelList, width, height):
    pixels = np.array([(q(r), q(g), q(b)) for r, g, b in pixelList], dtype=np.uint8)
    return pixels.reshape([height, width, 3])


def q(val):
    remainder = val % 43
    quotient = val // 43
    return (
        quotient * 43 if remainder < 43 // 2 or quotient == 5 else (quotient + 1) * 43
    )


def main():
    img = Image.open(IMG_PATH)
    quantised_pixels = quantise(list(img.getdata()), img.width, img.height)
    quantised_img = Image.fromarray(quantised_pixels, mode="RGB")
    quantised_img.save("result.png")


if __name__ == "__main__":
    main()