[Insight-users] Question about multiResolutionPyramidImageFilter class

[Luis Ibanez]

Hi Kaveh,

Yes, Jeffrey Duda's work is quite relevant here.


Although,
there may have been multiple efforts in this front.


Regarding your questions:

1) VectorResampleImageFitler:

    This class will take as input an image whose
     pixels have multiple components and will
     resample it with another image's grid, and by
     applying a geometrical Transform in between.

     You could use this class for generating the
     multiple resolution levels of the image pyramid.
     Note that in principle you need just to connect
     an Identity Transform, and to manipulate the
     number of pixels and pixel spacing of the output
     grid, in order to generate sub-resolution images
     that cover the same physical extent as the initial
     image.

2)  Yes, a Deformation field is essentially an image
     whose pixels are Vectors (in the geometrical
     sense: that is, they indicate the relative position
     between two points).

3)  For the purpose of constructing the image
     Pyramid, you don't need to worry about the
     differences between CovariantVectors and Vectors
     (strictly speaking ContravariantVectors).
     All the pixels in the deformation field will be
     "Vectors".


BTW, I you would like to contribute code, you could
request to have write access to the NAMIC Sandbox.

Please let me know if you would be interested in
doing so.


    Luis


-------------------------------------------------------------------------------
On Mon, Oct 12, 2009 at 2:40 PM, Kaveh Kohan <kaveh.kohan at yahoo.com> wrote:
> Dear Luis,
>
> Thank you for your reply.
>
> Is it the same effort as this (I mean that this code is uploaded by the same
> people). This one sound very comprehensive:
>
> http://www.seas.upenn.edu/~jtduda/itkvector.html
>
> I have a another question which sounds orthogonal but it is very relevant:
>
> There is also another class in ITK for vectorial image "
> VectorResampleImageFilter" but it seems that it is mostly used for
> deformation field expansion. I am wondering what is the difference?
> DeformationField is basically a vectorial image isn't it? Since there have
> been classes in ITK to do multiResolution image registration (for scalar)
> and as a part of that one needs to apply the same pyramid on deformation
> field (VectorResampleImageFilter), I thought it is very natural to have this
> class imeplemented for vectorial image pyramid. Please illustrate me if I am
> missing something in my induction. Does it have anything to do with
> difference between covector and vector image (I am sorry if it is
> irrelevant)?
>
> Thanks,
>
>
> ________________________________
> From: Luis Ibanez <luis.ibanez at kitware.com>
> To: Kaveh Kohan <kaveh.kohan at yahoo.com>
> Cc: insight-users at itk.org
> Sent: Mon, October 12, 2009 12:41:57 PM
> Subject: Re: [Insight-users] Question about
> multiResolutionPyramidImageFilter class
>
> Hi Kaveh,
>
> Unfortunately,
> I think that the answer to both question is : no.
>
> On the bright side, however, there have been some efforts
> for extending the Image Registration Framework to  support
> vector images.
>
> The major components to be modified are the Image metrics.
> A couple of Vector Image interpolators are already available,
> and the other components (Optimizer, Transform) are image
> agnostic.
>
> See for example:
> http://svn.na-mic.org/NAMICSandBox/trunk/VectorImageRegistrationMethod/
>
>
> You may want to join these efforts.
>
>
>     Regards,
>
>
>           Luis
>
>
>
> --------------------------------------------------------------------------
> On Sat, Oct 10, 2009 at 6:38 PM, Kaveh Kohan <kaveh.kohan at yahoo.com> wrote:
>> Hello Everybody,
>>
>>
>> I have two questions and I would appreciate if anybody answer:
>>
>> 1. I have a question about MultiResolutionPyramidImageFilter class. I was
>> wondering whether it accepts vector image (i.e. image voxels of which is
>> not
>> scalar but vector) as input or not.
>>
>> 2. Plus I am wondering is there any available example of multi-resolution
>> re-sampling of vectorial image available in ITK?
>>
>> Thnka you very much,
>>
>>
>>
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>
>