如何有效地计算numpy中面具中距离最近1的距离？

Question

In numpy I have a 2d array of 1s and 0s. I need to calculate a new array (same dimensions) where each element contains the distance to the nearest 1 from the corresponding point in the mask array.

eg

a=np.array(
[[1,1,0],
[1,0,0],
[1,0,0]])

I need b to look like this:

array([[0,0,1],
       [0,1,1.41],
       [0,1,2]])

PS. I'll be doing this over very large arrays, so the more efficient the better! Thanks!

Answer 1

You're looking for the equivalent of MATLAB's bwdist ; check out this SO question for more details. The short answer is to use scipy.ndimage.morphology.distance_transform_edt .