EndPoints in 3D skeleton

I have a 3D Skeletonized Micro-CT Fiber model which obtains completely seperated 7 volumes(fibers). I would like to find the endpoints of each and every fiber and I used below commands to find the end points.

B1=bwskel(testvol,'Minbranchlength',20);

BP = bwmorph3(B1,'endpoints');

Endpoints_Cor=regionprops3(BP,'VoxelList');

stats4=regionprops3(B1,'Volume','VoxelList');

However, my model obtains 7 volumes which are completely seperated. But it gives only 13 endpoints(But I am expecting 14 end points.7*2=14). I noticed one of the endpoint of my third volume does not obtain in the end point list. only one end point is in the list. Could you please explain how I should obtain all the endpoints in each and every volume and why I am missing one endpoint of the third volume? And also, is there anyway to categorise which endpoints belongs to which volume?

Your answers are highly appreciated!

Answer 1

[Image Analyst]

bwmorph() has an 'endpoints' option. The image should be a skeleton. bwmorph() also has a skeleton option but I think bwskel() has a better algorithm.

[Hege]

Thank you Image Analyst!

Yes. After importing denoised and binarised CT Volume, I used bwskel() in order to acquire the skeleton and then used bwmorph3() to detect the endpoints under 'endpoints' option. But I really dont have idea why one of the endpoint is missing in the output result. However, regionprops3() of the whole volume clearly says whole domain obtains 7 volumes and I expected 14 endpoints. Unfortunately, it gives me 13 endpoints that I have no idea to rectify the issue and why and how it occurs. But I went through all the points of each and every volume manually and found that one of the endpoint of the volume (3) missed in the endpoints list.

I really apperciate your valuable comments and advices!

[Image Analyst]

Have you seen bwferet():

https://www.mathworks.com/matlabcentral/answers/793992-how-to-find-the-end-point-coordinates-of-an-object-in-binary-image#answer_669822

[Hege]

Thank you so much Image Analyst.

I tried bwferet(). Unfortunately, I have a CT Volume (3D Image) and bwferet() doesnot work. I searched whether there is any 3D syntax for bwferet() is available or not. But I could not find.

Apprecite if you could give me a tip if there is any available solution!

[Image Analyst]

You can do a brute force loop to find the distance of every point to every other point.

[Hege]

Thank you so much Image Analyst! I really appreciate your answer.

What I did was, found the minimum distance for each and every voxel and rearranged the regionporops3() data as I want using a one ending point of each volume.

Thank you so much!