[Insight-users] Questions about the fast marching and level set filters

[Joshua Cates]

Hi Luca,

Yes the level set is calculated to subvoxel accuracy as in Whitaker's
implementation.  The implementation in Insight is based on that described
in "A Level-Set Approach to 3D Reconstruction from Range Data" Whitaker,
International Journal of Computer Vision 29(3), 203-231, 1998.

Josh.

______________________________
 Josh Cates
 School of Computer Science
 University of Utah
 Email: cates@sci.utah.edu
 Phone: (801) 587-7697
 URL:   www.cs.utk.edu/~cates


On Fri, 7 Jun 2002, Luca Antiga wrote:

> Dear users,
> dealing with sparse field and narrow band level sets. I know that sparse
> field method (at least in the implementation given by Whitaker in his
> library) ensures sub-voxel accuracy even with first order upwinding, by
> estimating level set position according to \phi and \nabla(\phi) and
> evaluating there all the quantities involved with evolution. Is this feature
> included in narrow band version?
> Thanks
>
> Luca
>
>
> >From: Bjorn Hanch Sollie <bhs@pvv.org>
> >To: insight-users <insight-users@public.kitware.com>, Joshua Cates
> ><cates@sci.utah.edu>
> >Subject: Re: [Insight-users] Questions about the fast marching and level
> >set filters
> >Date: Thu, 6 Jun 2002 19:29:35 +0200 (CEST)
> >
> >On Tue, 4 Jun 2002, Joshua Cates wrote:
> >
> > > You can use the SparseFieldLevelSetImageFilter for applications that
> >only
> > > care about a single level set (and you will almost certainly get some
> > > speed advantage by doing so).  I
> >
> >Thanks for answering some questions.  I've been looking at the
> >SparseFieldLevelSet filter examples, and as far as I can see, it
> >requires the potential map (or target image) to have positive values
> >on the inside of the region and negative values on the outside.  This
> >is in contrast to the potential map for the ShapeDetectionLevelSet
> >filter which wants values between 0 and 1.  My queston then is: What
> >is the best way of making a potential map for the SparseFieldLevelSet
> >filter from an edge image?  Just do a simple positive/negative
> >threshold on some grey value?  Are there any recommended (better?)
> >ways?
> >
> >-Bjorn
> >--
> >The History of the Universe
> >Chapter 1: Bang!  Chapter 2: Sss...  Chapter 3: Crunch!
> >The End
> >
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>
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