How do I get the fork points of a skeleton of an image?

I want to find the fork points of a skeleton of an image. I have obtained the skeleton of the image using the bwmorph(binaryImage, 'skel', Inf) function.

Answer 1

[Guillaume]

How about?

skelimage = bwmorph(binaryImage, 'skel', Inf);
branchimage = bwmorph(skelimage, 'branchpoints');

[Image Analyst]

S.P., you might want to look over the bwmorph() documentation. It can do so much more than skel - there is a huge list of things it can do so you should at least look it over because there are other things in there you will use someday, like perhaps endpoints or whatever.

[Soumyajit Pal]

Thank you for commenting. I have gone through the documentation a number of times but there's nothing mentioned regarding fork points. Keywords like 'endpoints' and 'branchpoints' are present but nothing like 'fork'.

[Image Analyst]

Please provide a small skeleton image showing whatever you call a "fork" point, and show us how the code for finding "branchpoints" does not work to find the same points. Otherwise we have nothing to visualize and can't imagine why it would not work to do what you need to do.

[Soumyajit Pal]

A skeleton point having only one adjacent point is called an endpoint. A skeleton point having more than two adjacent points is called a fork point. A skeleton segment between two skeleton points is called a skeleton branch. Every point which is not an endpoint or fork point is called a branch point. Could you please help now?

[Guillaume]

"A skeleton point having more than two adjacent points is called a fork point": bwmorph calls this a branch point.

"Every point which is not an endpoint or fork point": these are just a normal segment point. It does not have a particular name, and I don't see why you'd call them branch point. If you want to obtain these, it's just the skeleton point minus the end and branch points:

skelimage = bwmorph(binaryImage, 'skel', Inf);
branchimage = bwmorph(skelimage, 'branchpoints'); %branch (fork) points
endimage = bwmorph(skelimage, 'endpoints'); %end points
otherimage = skelimage - branchimage - endimage; %points other than branch and end

[Soumyajit Pal]

Thank you so very much Guillaume.