CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

Le lundi 14 mai 2012 11:29:01 Andrea Cortis a écrit :
> Dear All,
> 
> I am new to CGAL and seeking help on how to generate a 3d mesh from a
> segmented image.
> So far I have been able to run the examples at
> 
> [1]
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Mesh_3/Chapter_main.
> html#Subsection_50.3.3
> 
> [2]
> http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Surface_mesher/Chapt
> er_main.html
> 
> I have also run some examples on my own images, but I am finding some
> problems with segmented images that consist of isolated regions. In
> particular, I have noticed that, generally speaking (1) only some of
> the isolated regions are correctly spotted, and (2) which regions are
> spotted depends on the center and radius of the ball in link [2] and,
> for the same radius and center, it depends on the particular
> random_seed number.
> 
> I have uploaded a "test.inr" file at this location:
> 
> http://www.tempfiles.net/download/201205/243508/test.html
> 
> (Please let me know if you are able to download it correctly)
> 
> 
> 
> I would greatly appreciate any help on this problem. Thanks in advance,

Do you have a way to know in advance how many isolated regions you have, do 
you have a way to find an rough enclosing sphere for each (with the 
constraint 
that the center of the sphere is inside the region)? In that case I might 
help.

The issue is the initialization step of the meshing process. It uses random 
ray queries, issuing from the center of the sphere you give. To find out all 
regions, one needs to run that process for each region.

-- 
Laurent Rineau, PhD
R&D Engineer at GeometryFactory           http://www.geometryfactory.com/
Release Manager of the CGAL Project       http://www.cgal.org/