A function to segment a binary image

segmentation.py

import numpy as np
import matplotlib.pyplot as plt
import cv2


def segment(src=None):
    img = cv2.copyMakeBorder(src, 1, 1, 1, 1, cv2.BORDER_REPLICATE)

    tags = np.zeros(img.shape)

    for i in range(1,img.shape[0]-1):
        for j in range(1,img.shape[1]-1):
            for k in range(i-1, i+2):
                for l in range(j-1, j+2):
                    if tags[k, l] != 0 and img[k, l] == img[i, j]:
                        if tags[i, j] != 0:
                            tags[tags == tags[i, j]] = tags[k, l]
                        else:
                            tags[i, j] = tags[k, l]

                    if k == i+1 and l == j+1 and tags[i, j] == 0:
                        tags[i, j] = np.max(tags) + 1

    return tags[1:-1,1:-1]/np.max(tags)*255

Using this code

img = np.array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
                [0, 0, 1, 1, 0, 0, 1, 1, 0, 0],
                [0, 0, 1, 1, 0, 0, 1, 1, 0, 0],
                [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
                [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
                [0, 0, 1, 1, 0, 0, 1, 1, 0, 0],
                [0, 0, 1, 1, 0, 0, 1, 1, 0, 0],
                [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])*255


plt.subplot(1, 2, 1)
plt.imshow(img, cmap='gray')

plt.subplot(1, 2, 2)
plt.imshow(segment(img), cmap='gray')
plt.show()

We can obtain:

Where each gray level is a region in the right image.