Can I make bwareafilt keep any ties for n-th place?

I've been using bwareafilt, but keep getting warnings that there are ties for n-th place, and that the ties were not selected. Is there any way to make it keep any ties for n-th place?

Answer 1

[Image Analyst]

Please post your binary image where this happens. Also state the criteria where you'd delete one. For example, if you take the two largest blobs and they are both exactly 10,000 pixels and it keeps them both, then do you just want to randomly select one for deletion? Or just delete the one on top (or left, right, bottom)?

[Nick Fliss]

Thank you for the reply. It’s actually a video, I can’t post it at the moment, but I’ll post it when I’m able. What I want it to do is, if there is a tie for largest blob, to keep both blobs.

[Image Analyst]

Use bwareafilt() in a different way. See demo below:

mask = false(640, 480);
mask(50:100, 50:100) = true;
mask(150:200, 150:200) = true;
mask(350:370, 100:120) = true;
subplot(2, 2, 1);
imshow(mask);
title('Mask', 'FontSize', 30);

% Keep largest blob only.  See if it keeps both since they are tied.
mask2 = bwareafilt(mask, 1);
subplot(2, 2, 2);
imshow(mask2);
title('Filtered Mask', 'FontSize', 30);
% It does not keep both!

% To keep both we need to measure the size and
% use bwareafilt() in a different way
props = regionprops(mask, 'Area');
allAreas = [props.Area]
maxArea = max(allAreas)
mask3 = bwareafilt(mask, [maxArea, inf]);
% Now keep anything maxArea or larger
subplot(2, 2, 3);
imshow(mask3);
title('Filtered Mask', 'FontSize', 30);
% This will keep both.

[Nick Fliss]

Thank you for the help! I didn't get a notification, so I just saw this today.