[Insight-users] simplest way to find the zero level set ( no evolution necessary)

[Luis Ibanez]

Hi Liam,

You may find useful to study the internal implementation of itk Level 
Set filters. In particular the SparseFieldLevelSetImageFilter.

            Insight/Code/BasicFilters
               itkSparseFieldLevelSetImageFilter.h

You will find that the values (and positions) of the LevelSet are
stored only for a couple of layers of pixels around the Zero Set.

You could reuse such structure, and implement on top of it, the
calculation of the radial basis functions.

Of course, once you do this, it will be great to post your code,
along with a technical report, to the Insight Journal   :-)


    Regards,


        Luis


-----------------------
quantumLeaf wrote:
> Hi,
> 
> I want to use ITK to find the zero level set of an implicit function. 
> I want to find a list of points about the zero contour so that i can perform
> a numerical integration over it. 
> I've been reading the manual and looking at the level set methods in ITK.
> These methods seem to be more complicated than i need since i dont wish to
> evolve the embedding function in ITK. 
> 
> It trying to implement the method described in 
> 'A Variational Approach to the Evolution of Radial Basis Functions for Image
> Segmentation'
> http://www.cs.stevens.edu/~quynh/papers/Slabaugh_RBFevolution_CVPR07.pdf
> 
> The function is a sum of RBFs. Once i can do the integration over the zero
> contour of the current state of the field i can evolve the RBF parameters. 
> 
> How can i use ITK to get coordinates along the zero level set of my
> function? 
> 
> if anyone reading can see some conceptual mis-understanding or problems in
> my approach, please let me know.
> 
> best regards,
> 
> Liam
> 
>