[Insight-users] "Forbidden area" in Level Set?

[Joshua Cates]

Hello Sah,

Your instincts are correct.  To keep the time step reasonable, try
modifying your speed term so that it goes more smoothly to zero at the
boundaries of the regions you that you don't wish the surface to enter. =20
See also the itkAntiAliasBinaryImageFilter for clues on how to apply
constraints to the evolution of the level-sets (you'll have to override
some methods in your subclasses of SegmentationLevelSetImageFilter).

Josh.

______________________________
 Josh Cates=09=09=09
 Scientific Computing and Imaging Institute
 University of Utah
 (801) 587-7697
 http://www.sci.utah.edu/~cates


On Fri, 5 Mar 2004, Sah Rayman wrote:

> I wish my level set never evolve to some area in the
> image. Those area was obtained by another application.
> What can I do?
>=20
> I tried to put a negative speed for those areas. But
> level set will balance with other factors, and still
> enter those region.=20
>=20
> When I increase the negative speed to a very large
> value(compared to other speeds), it now don't enter
> those region. But whenever the edge touches those
> region, speed for everywhere else decrease a lot.
> (Because "timeStep =3D
> df->ComputeGlobalTimeStep(globalData)" will be very
> small so that it's stable)
>=20
> Is there any other way mark a region "non-enterable"?
>=20
> __________________________________
> Do you Yahoo!?
> Yahoo! Search - Find what you=92re looking for faster
> http://search.yahoo.com
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
>=20