img_aux = np.array([[1, 1, 1,1,1,1,1,1], #3x3 kernel
[1, 0, 1,0,0,1,0,1],
[1, 1, 1,1,0,1,0,1],
[1, 1, 1,1,0,1,0,1],
[1, 1, 1,1,0,1,0,1],
[0, 0, 0,0,0,0,0,0],
[1, 1, 1,1,0,1,0,1],
[1, 1, 1,1,0,1,0,0]])
print(img_aux.shape)
plt.imshow(img_aux,cmap='gray')