[Insight-users] Are isotropic volumes a must for levelset algorithms or preferable?

[Luis Ibanez]

Hi Sara,

As Koen, already mentioned, is it not that the LevelSet MUST use
isotropic data, but that it is PREFERABLE to have close-to-isotropic
data.

There are cases in which anisotropy is abused at image acquisition
time. For example, instances in MRI (and microscopy) where the
inter-slice spacing is five to ten times larger than the in-plane
spacing.

At such levels it is hard to claim that you have a 3D datasets,
and it is a lot better to accept that the dataset is a collection
of losely correlated 2D slices.

Enabling the use of spacing in an anisotropic dataset, will be fine
for LevelSets if you are working on a dataset with an anisotropy
ratio of less than 5:1. Beyond that, you probably should simply
run 2D level sets on each one of the slices...


Do you have a specific value of anisotropy in mind  ?


    Please let us knonw,


       Thanks



          Luis



-------------------------
sara meghellati wrote:
> Dear itk users,
> 
> I have already found in the mailing list that LevelSet algorithms expect 
> the data to be represented with isotropic pixels. I would like to know 
> if this is a MUST to perform the level set algorithms or just 
> is PREFERABLE in order to have good results.
> 
> Thanks
> 
> Sara
> 
> 
> 
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