label two objects that share part of the same boundary separately
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I have a matrix like this:
m = [0,1,1,1,0;1,0,0,0,1;0,1,1,1,0;0,1,0,1,0;0,0,1,0,0];
And I want to label the interior separately, which results in a matrix like this:
m1 = [0,1,1,1,0;1,2,2,2,1;0,1,1,1,0;0,1,3,1,0;0,0,1,0,0];
But I'm not sure how to do that. Any suggestion will be appreciated! Thank you!
Steve Eddins on 3 Aug 2022
m = [0,1,1,1,0;1,0,0,0,1;0,1,1,1,0;0,1,0,1,0;0,0,1,0,0]
Fill the holes. From your example, it looks like the background connectivity should be 4.
filled_holes = imfill(m,4,'holes')
The pixels that were added are the holes.
hole_pixels = filled_holes & ~m
Label the hole pixels.
L = bwlabel(hole_pixels,4)
Add the labels (incremented by one) to the original matrix.
m_out = m;
m_out(hole_pixels) = L(hole_pixels) + 1