[Insight-users] variable voxel spacing and anisotropic diffusion

[Mauro Maiorca]

Thank you very much for pointing out the insight-developers mailing list!!

Regards,
Mauro


2011/4/5 Dženan Zukić <dzenanz at gmail.com>:
> Maybe you should ask this question on insight-developers mailing list?
> Perhaps there is some difference.
> HTH
>
> On Sun, Apr 3, 2011 at 06:36, Mauro Maiorca <mauromaiorca at gmail.com> wrote:
>>
>> nobody? :-(
>>
>> what I've done so far is transforming the input image with variable
>> voxel spacing into one with constant voxel spacing (by using
>> interpolation), then applying anisotropic diffusion, finally
>> interpolating back the image to the original (variable) spacing. Well,
>> it works, and I can apply any filter without worrying about the
>> variable voxel spacing.
>>
>> However, I'm afraid this (re)interpolation trick might affect the
>> final quality of the image, furthermore I'm just interested to few
>> anisotropic diffusion filters. Thus, I'm still looking forward to find
>> a way to modify the anisotropic diffusion filters already implemented
>> in ITK in order to tackle the problem without using interpolation. Itk
>> source code is well documented (thanks for that), but it's a quite big
>> package, and it would be great to have directions regarding where in
>> the code I should get my hands dirty on and what's the cleanest way to
>> do it. I reckon itkFiniteDifferenceImageFilter.txx is one of the first
>> target files I should inspect, and I guess at some stage I should play
>> with the function
>> void FiniteDifferenceImageFilter<TI,TO>::initializeFunctionCoefficients()
>> I would like to treat the "voxel spacing mask" as image, something like
>> that:
>> typedef itk::Image<double, Dimension> variableVoxelSpacingMaskType;
>> variableVoxelSpaceMaskType m_variableVoxelSpaceMask;
>> I guess I have also to ask the user to insert the voxel space "mask"
>> with a sort of SetVoxelSpaceMask() somewhere.
>>
>> Unfortunately, as you can see I have only fragmentary ideas of
>> how/where I should modify the code, so any input would be appreciated.
>> Since I haven't received any answer so far, please let me know whether
>> I didn't explain my problem clearly enough, or maybe whether you think
>> it's too complicate to be easily solved within the ITK toolkit.
>>
>> Regards,
>> Mauro
>>
>>
>> On Mon, Mar 28, 2011 at 6:57 PM, Mauro Maiorca <mauromaiorca at gmail.com>
>> wrote:
>> > Hello Itk-users,
>> >
>> > I'm successfully using anisotropic diffusion filters on n-dimension
>> > volumes.
>> > Unfortunately, many of my volumes don't have uniform voxel spacing. In
>> > fact, in the simplest 3D scenario (n=3, x1=x, x2=y, x3=z) I can
>> > summarise the voxel spacing within my images with a function f:R^3->R,
>> > where df/dx=0, df/dy=0 df/dz=k (k constant). I was wondering whether
>> > there is a way to apply diffusion parameters independently for each
>> > dimension, or according to some sort of mask.
>> > If negative, can you please point me to the quickest/cleanest way to
>> > implement it within ITK (i.e. which files I need to modify, etc)? I'm
>> > more then happy to share the code (InsightJournal) if other people
>> > might be interested on this.
>> >
>> > thanks a lot,
>> > Mauro
>> >
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>