[Insight-developers] Level Set Function

[Joshua Cates]

Hi Paul,

This sounds fine to me.  One more if statement shouldn't make much 
difference and others might want to subclass to use your Laplacian term 
as well.  Glad the framework is working out for you!

Josh.

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


On Thu, 12 Jun 2003, Paul Yushkevich wrote:

> Hi Josh,
> 
> I've just been examining your implementation of the level set function 
> and comaring it to the SNAP level set formulation.   I really like your 
> implementation because it's generic, and almost all the terms of the 
> SnAP function can be folded into the LevelSetFunction using the 
> CurvatureSpeed, PropagationSpeed and AdvectionField virtual functions.
> 
> There is one term in the SNAP equation that is not in the Level Set 
> function.  This is a very simple term used for smoothing the level set 
> function over time in order to prevent instabilities. This is just the 
> Laplacian of \phi multiplied by a weight and by it's own speed function, 
> which is usually identity.
> 
> What would you say if I add the Laplacian term to the level set function 
> formulation?  That is, I will add Get/SetLaplacianSmoothingWeight() and 
> GetLaplacianSmoothingSpeed() methods and add an 
> if(LaplacianSmoothingWeight != 0){} clause to the ComputeUpdate() method.  
> 
> The reason that I want to add the laplacean computation to the existing 
> ComputeUpdate method in LevelSetFunction is because this computation 
> requires finite differences that are already being computed in this 
> method for calculating curvature and gradient.  It would be beneficial 
> to reuse these terms.  The computational cost of this addition will be 
> one more 'if' statement for existing level set implementations.
> 
> Thanks!
> 
> Paul.
> 
> 
> 
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