[Insight-users] confirmation of isotropic spacing requirement for levelset filters in ITK

Luca Antiga luca.antiga at gmail.com
Mon Dec 10 11:41:34 EST 2007


Hi all,

>> However, as Karthik pointed out, it remains to be seen whether there
>> are other places where the spacing should have been taking into  
>> account.
>> (and may have not been used correctly).

from what I recall, spacing is important in the  
itk::SparseFieldLevelSetImageFilter
class, which is a child of itk::FiniteDifferenceImageFilter and a  
base class for most
of the actual level sets classes.
itk::SparseFieldLevelSetImageFilter contains all the machinery needed  
to track the
zero level front, which includes computing upwind gradients and  
evaluating the
distance of the zero level set from the voxels in the various layers.  
That part I
believe is the hardest part that needs to be revisited if one wants  
to allow
anisotropic spacings in level sets.

Other than this, also other bits, like  
itk::SegmentationLevelSetFunction::AdvectionField,
assume uniform spacing, but they are definitely easier to fix.

I'll be happy to give my contribution if you want to embark in this  
adventure!
I think this would make it for a very useful generalization (I know,  
Luis, I know we should
ask our radiologists to acquire at isotropic resolutions... :-) )

Cheers

Luca

--
Luca Antiga, PhD
Head, Medical Imaging Unit,
Bioengineering Department,
Mario Negri Institute
email: antiga at marionegri.it
web: http://villacamozzi.marionegri.it/~luca
mail: Villa Camozzi, 24020, Ranica (BG), Italy
phone: +39 035 4535-381


On Dec 10, 2007, at 5:22 PM, Charl Botha wrote:

> On 12/10/07, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>> However, as Karthik pointed out, it remains to be seen whether there
>> are other places where the spacing should have been taking into  
>> account.
>> (and may have not been used correctly).
>
> Karthik and Luis, thanks for your rapid and informative answers!
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users



More information about the Insight-users mailing list