[Insight-users] Polar transforms

[Luis Ibanez]

Hi Jakub,


Thanks for your willingness to contribute your code to ITK.

We will be happy to add your transform to the toolkit.

Could you please send us the files (.h and .txx) along with
a test for this transform.  The test should exercise all the
methods of the new class.

Please let us know too how do you want the credits for authorship
to be listed in the header file.  Typicall we follow the Doxygen
format of:


   \author John Doe, Department of Surgery, University of Zion



   Thanks


      Luis



---------------------
Jakub Bican wrote:

>  
> Hi all,
>  
> i am implementing a multidimensional polar transform. It transforms 
> first two dimensions of cartesian space into <angle,radius> coordinates, 
> leaving the other dimensions unchanged (i.e. - multidimensional 
> cylindric transform). I have implemented both forward and backward 
> transforms. To transform space to cylinder in general position (to 
> transform other than first two dimensions), it is neccessary to 
> transform the image first by for example Euler3DTransform, or 
> PermuteAxesImageFilter. To avoid excess memory and time, i implemented 
> PermuteAxesTransform, which does the same as the filter, but it is a 
> transform.
>  
> Now i have two possibilities what to do:
> 1) imlement something like "bulk transform" as it is in 
> BSplineDeformableTransform into the polar transforms, or
>  
> 2) implement general "ComposeTransformsTransform", which keeps a queue 
> of transforms and successively transforms points and vectors by all of 
> them. So it is possible to do several transforms in just one 
> ResampleImageFilter.
>  
> I find the second solution more laborious but principally much more 
> useful. But before i will do it, i need to know surely, if there is not 
> such class in ITK yet, because i did not find it and i think that it is 
> really useful and it should be implemented. Or is there any other way 
> how to pass several transforms into one ResampleImageFilter??
>  
> I also found AzimuthElevationToCartesianTransform class in ITK. This 
> does a kind of spheric transform and i must say that it is implemented 
> badly. It uses several parameters to "sample" the "polar" space once 
> more. All these parameters are redundant to properly set Size, Spacing 
> and Origin parameters of ResampleImageFilters output and only comlicates 
> the situation. Keeping in mind that transforms are transforming "real" 
> coordinates, such transforms as polar, cylindric or spheric do not need 
> any parameters. Everything is just question of proper sampling of input 
> and output space.
>  
> Finally, i found several requests for polar transforms in insight-users 
> archives, so if it is still open and if it is possible, i would be 
> pleased to submit my classes into ITK.
>  
> Regards
> Jakub
> 
> 
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