edge_detection.py

import math
import sys

from PIL import Image, ImageFilter

# ensure correct usage
if len(sys.argv) != 2:
    sys.exit("Usage: Python3 edge_detection.py imagefilename")


# open image
image = Image.open(sys.argv[1]).convert("RGB")

# filtered image according to edge detection kernel
filtered = image.filter(ImageFilter.Kernel(
    size=(3, 3),
    kernel=[-1, -1, -1, -1, 8, -1, -1, -1, -1],
    scale=1
))

# show resulting image
filtered.show()