How to select only round objects from this image?

I am working on images that have round and some non-round objects and I want to select only the round objects. How can I select only round objects from the image in post https://www.mathworks.com/help/images/identifying-round-objects.html ?

Any help is appreciated.

Answer 1

[Image Analyst]

Threshold the image to get the blobs, then compute circularities and filter to get those with circularities near 1:

mask = imbinarize(grayImage);
mask = imfill(mask, 'holes');
labeledImage = bwlabel(mask);
props = regionprops(mask, 'Area', 'Perimeter');
allAreas = [props.Area];
allPerimeters = [props.Perimeter];
circularities = allPerimeters .^ 2 ./ (4 * pi * allAreas);
% Get those blobs with circularity near 1.
roundindexes = find(circularities > 0.8 & circularities < 1.5)
% Get new mask
roundBlobs = ismember(labeledImage, roundIndexes);
imshow(roundBlobs);
title('Only the round blobs')

[Mohammad Farhad Aryan]

Thank you very much.

It worked!

[Amal]

what is the function ismember

[Image Analyst]

ismember tells you if some or all of one list is contained in another list.