https://twitter.com/inaniwa3/status/1255116782303469568

mu.py

#!/usr/bin/env python

# ref.
#   伝説の超古代文明「ムー」
#   http://www.nazotoki.com/mu.html

import cv2
import numpy as np

kernel7 = np.array([
    [0, 0, 1, 1, 1, 0, 0],
    [0, 1, 1, 1, 1, 1, 0],
    [1, 1, 1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1, 1, 1],
    [0, 1, 1, 1, 1, 1, 0],
    [0, 0, 1, 1, 1, 0, 0],
    ], np.uint8)
kernel5 = np.array([
    [0, 1, 1, 1, 0],
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1],
    [1, 1, 1, 1, 1],
    [0, 1, 1, 1, 0],
    ], np.uint8)

mu = cv2.imread('mu.png', cv2.IMREAD_GRAYSCALE)
pacific = cv2.imread('pacific.png', cv2.IMREAD_COLOR)
dilation = cv2.dilate(mu, kernel7, iterations = 6)
gradient = cv2.morphologyEx(dilation, cv2.MORPH_GRADIENT, kernel5)
idx = gradient[...] == 255
pacific[idx] = [0, 0, 255]
cv2.imwrite('eez.png', pacific)