[Insight-users] Selecting the sigma for the vesselness

[rashedk]

Hi Chris, 

Doesn't Manniseng's VED filter *enhance* the vessels rather than detecting
them? It does do multi-scale analysis, but goes one step further by applying
the appropriate diffusion (iso- or aniso-) process. So the output of the VED
filter should be the same image with the vessels enhanced and not the
vesselness. Please, correct me if I am wrong. 

What I also don't understand is why Hessian3DToVesselnessMeasureImageFilter
does not implement a multiscale approach? If it is Frangi's vesselness which
is implemented here, then his paper did suggest returning the highest
response by varying the sigma. 

Regards, 
Rashed



Chris McIntosh-2 wrote:
> 
> Hello,
> 
> I'm not sure if this helps, but just in case.
> 
> In general, using a constant sigma for an image is troublesome because 
> the ideal scale for each vessel
> is the actual radius of that vessel (in voxels). So you need a different 
> scale at each voxel.
> 
> I would suggest looking at:
> http://hdl.handle.net/1926/558
> 
> They implement a powerful multi-scale technique for vessel filtering, 
> where each pixel's response
> is tested under a range of scales and the maximal response is taken.
> 
> 
> Cheers,
> 
> Chris
> 
> rashedk wrote:
>> Hi everyone, 
>>
>> I am currently using the vesselness filters to detect vessels. I use a
>> pipeline with HessianRecursiveGaussianImageFilter and
>> Hessian3DToVesselnessMeasureImageFilter filters which works fine.
>> However, I
>> am using a trial and error approach for selecting the sigma. In a
>> previous
>> post I came across an approach whereby sigma selection can be done
>> effectively by observing the responses of a single pixel that is known to
>> be
>> part of a vessel (a.k.a multi-scale analysis). How do I constraint the
>> above
>> filters to only process a single pixel and not the entire image? 
>>
>> Thanks, 
>>
>> Rashed Karim
>>   
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