[Insight-users] Laplacian level set filter

[Luis Ibanez]

Hi Radhika,

Did the LaplacianSegmentationLevelSet
filter use all the iterations that you set ?

That its, did it reached the target RMS error
before using all the iterations ?

If not,
your parameters are probably too conservative.

If you need to accelerate the propagation of
the front you could try using values as high
as 10 to 100 for the Translation scaling as
well as the Advection scaling.

Please also check visually the result of
smoothing the MRI image before you pass it
as input to the LevelSet filter.


Regards,


    Luis



--------------------------------
Radhika Sivaramakrishna wrote:

> Hi Luis,
> 
> I was trying to use the Laplacian level set (with anisotropic diffiusion 
> as a preprocessing step) to improve an already available initial mask. 
> These are 3D brain T2-weighted images.
> 
>  
> 
> I set the # of iterations for diffusion as 10
> 
> Time step for diffusion = 0.125
> 
> Conductance parameter for diffusion = 2.0
> 
>  
> 
> Curvature scaling = 1.0
> 
> Propagation Scaling for Laplacian =  1.0
> 
> # iterations for Laplacian = 10
> 
> Isosurface value = 127.5
> 
> Maximum rms error for laplacian = 0.002
> 
>  
> 
> The initial mask was quite approximate but the solution was a good 
> starting point. However, after running with above settings, I found very 
> marginal improvement.
> 
> I was playing with some of the parameters but did not see significant 
> improvement.
> 
>  
> 
> So my question was, for a 3D MRI T2-weighted image,
> 
>  
> 
> 1)       what are the recommended values for the above parameters
> 
> 2)       What is the range of reasonable values to "play with" for each 
> of these parameters?
> 
> 3)       What are the parameters for the Laplacian scaling that make the 
> growing surface move faster? It seems to me that the advancement at each 
> iteration is very less.
> 
>  
> 
> Thanks
> 
> Radhika
> 
>  
> 
>  
> 
>  
> 
>  
> 
>  
> 
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