[Insight-users] ReinitializeLevelSetImageFilter

[Karthik Krishnan]

Bryn:

I don't think that is true. The Reinitialize level set filter simply relies
on the fast marching filter to generate the signed distance function. The
fastmarching filter does take voxel anisotropicity into account when
marching the level set front.

See the lines involving the update equation in itkFastMarchingImageFilter.h

      const int axis = node.GetAxis();
      const double spaceFactor = vnl_math_sqr( 1.0 / spacing[axis] );
      const double value = double(node.GetValue());
      aa += spaceFactor;
      bb += value * spaceFactor;
      cc += vnl_math_sqr( value ) * spaceFactor;


On Fri, Mar 6, 2009 at 8:06 AM, Bryn Lloyd <blloyd at vision.ee.ethz.ch> wrote:

> Hi all,
>
> Do I understand correctly that the ReinitializeLevelSetImageFilter does not
> use the spacing of the input image?
>
> If yes, I guess I need to resample the input image, in order to be
> isotropic AND scale the results in order to have Euclidean distances. Right?
>
> Thanks
> Bryn
>
>
>
>
>
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-- 
Karthik Krishnan
R&D Engineer,
Kitware Inc.
Ph: 518 371 3971 x119
Fax: 518 371 3971
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