Mask¶
Define a binary mask to access a part of the image.

The mask is basically a 2D array of booleans that select pixels.
import imageio
import numpy as np
a = imageio.imread("bbtor.jpg")
h, w = a.shape[0], a.shape[1]
Y, X = np.ogrid[0:h, 0:w]
mask = (X - w / 2) ** 2 + (Y - h / 2) ** 2 > w * h / 6
a[mask] = 0
imageio.imsave('mask.png', a)
Challenge¶
Modify the code to create your own mask shape.