MATLAB: Removing black holes from within a white circles

image processingImage Processing Toolbox

Hey, I want to remove the black patches that occur within the white circles, i tries using imfill(,'holes') but it turns the whole image white. I don't understand whats happening. Thanks

Best Answer

You have white stuff around the border of the image, which means that everything will get filled. So call imclearborder first

binaryImage = imclearborder(binaryImage);
binaryImage = imfill(binaryImage, 'holes');

If you need to put the white border back, let me know.

Related Solutions

MATLAB: Counting holes in an image

Threshold then call imclearborder() and bwlabel(). Assuming you have dark holes on a bright background:

% Binarize:
binaryImage = grayImage < someValue;
% Remove those touching border
binaryImage = imclearborder(binaryImage);
% Count holes:
[~, numHoles] = bwlabel(binaryImage);

MATLAB: Fill holes in binary Image

You could try imclose() followed by imfill()

se = strel('disk', 20, 0);
mask = imclose(mask, se);
mask = imfill(mask, 'holes');
imshow(mask);

or you could try an active contour, like the attached demo.

There are fancier ways if you want to make sure the outer boundary doesn't change, but it's more work and I don't have time for that now. See if one of the two methods I gave above works OK for you.

Best Answer

Related Solutions

MATLAB: Counting holes in an image

MATLAB: Fill holes in binary Image

Related Question