MATLAB Count spheres with overlap

Question

I am trying to count the number of spheres based on intensity value. The spheres are biomarkers from a CT scan. Therefore the center has the largest intensity. However, it is hard for me to count the spheres if there are overlaps. How can we figure out how to do the count of the spheres with overlap.

Answer 1

for a 3D binary image, you can call bwlabeln ( https://www.mathworks.com/help/images/ref/bwlabeln.html ) in the image processing toolbox to count/label isolated islands, but this can be slow.

if you download my iso2mesh toolbox ( http://github.com/fangq/iso2mesh ), you can also try the bwislands function

https://github.com/fangq/iso2mesh/blob/master/bwislands.m

or, create isosurfaces first and then count the closed surface components using finddisconnsurf in iso2mesh.

fv=isosurface(im, 0.5);
fc=finddisconnsurf(fv.faces);
length(fc)