Filling holes in objects that touch the border of an image

Question

I\'m trying to fill holes in the below image.

When I use SciPy\'s binary_fill_holes

Answer 1

This assumes that there is more background than other stuff. It basically does a connected component analysis on the image. Extract the largest component (assumed to be the background), and sets everything else to white.

import numpy as np
import matplotlib.pyplot as plt
import skimage.morphology, skimage.data

img = skimage.data.imread('j1ESv.png', 1)
labels = skimage.morphology.label(img)
labelCount = np.bincount(labels.ravel())
background = np.argmax(labelCount)
img[labels != background] = 255
plt.imshow(img, cmap=plt.cm.gray)
plt.show()