How to find the endpoint?
10 ビュー (過去 30 日間)
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Hi, i have an image and wanted to find the location of endpoints as shown in red circle.
I am using the
bw=bwmorph(bw,'endpoints')
however, it returns "0" instead of the location of endpoints.
How can I do with this? Thank you.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1025380/image.png)
2 件のコメント
採用された回答
DGM
2022 年 6 月 8 日
編集済み: DGM
2022 年 6 月 8 日
% image recovered from screenshot
A = imread('vessel.png');
A = A>128; % binarize
% skeletonize
B = bwskel(A,'minbranchlength',50);
% fill loops
B = imfill(B,'holes');
% skeletonize to get rid of filled loops
B = bwskel(B,'minbranchlength',50);
imshow(B) % display interpolation makes fine lines look spotty
% get endpoints as a logical image
endpts = bwmorph(B,'endpoints');
imshow(endpts) % again, display interpolation hides most of the dots
That result can be used for logical indexing if needed. If for some reason, you can't use it directly and need indices instead, you can use find().
% if you really truly need indices instead
endptidx = find(endpts)
6 件のコメント
DGM
2022 年 6 月 10 日
I'm not sure if your x,y for the reference center are flipped. it's outside the image region.
% image recovered from screenshot
A = imread('vessel.png');
A = A>128; % binarize
% skeletonize
B = bwskel(A,'minbranchlength',50);
% fill loops
B = imfill(B,'holes');
% skeletonize to get rid of filled loops
B = bwskel(B,'minbranchlength',50);
% get endpoints as a logical image
endpts = bwmorph(B,'endpoints');
% these might be flipped
x=500;
y=1000;
[endpt_Y endpt_X] = find(endpts); %[row col]
% this is the square of the euclidean distance
% if all you need is to optimize distance, there's no need for sqrt()
% if you actually need the distance for something else, you can add it.
Dsquared = sum(([endpt_Y endpt_X] - [y x]).^2,2);
% find most distal endpoint
[~,mxidx] = max(Dsquared);
mostdistal = [endpt_X(mxidx) endpt_Y(mxidx)]
% plot some stuff
imshow(B); hold on
plot(x,y,'x','markersize',20) % specified centroid
plot(mostdistal(1),mostdistal(2),'o','markersize',20)
ylim([0 1050]) % adjust axes to show marker
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