How detect spot white circle on image

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Duc Hang
Duc Hang 2017-6-6
评论： Rena Berman 2017-6-23
I would like detect spot white are like below image . Hope anyone help . Thanks!

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KSSV
KSSV 2017-6-6
编辑：KSSV 2017-6-6
I = imread('Screen Shot 2017-06-06 at 3.54.58 PM.png') ;
im = imclearborder(im2bw(I));
im_fill = imfill(im, 'holes');
s = regionprops(im_fill, 'Area', 'PixelList');
[~,ind] = max([s.Area]);
pix = sub2ind(size(im), s(ind).PixelList(:,2), s(ind).PixelList(:,1));
out = zeros(size(im));
out(pix) = im(pix);
% imshow(out);
[y,x] = find(out) ;
idx = boundary(x,y) ;
% idx = convhull(x,y) ;
imshow(I)
hold on
plot(x(idx),y(idx),'r','linewidth',3)
Code taken from: https://in.mathworks.com/matlabcentral/answers/343337-how-to-remove-small-portion-in-an-image
If boundary doesn't work, use convexhull

更多回答（1 个）

Image Analyst
Image Analyst 2017-6-6
KSSV's code finds the largest blob that is not touching the border, whereas you actually want roundish objects.
Like I said in your duplicate post, You could use my code for circularity. Or you could also look for Solidities close to 1, or get the BoundingBox and look for aspect ratios close to 1.

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