[Insight-developers] Re: Suggestion: Tensors and Tensor Image Filters

[Jeffrey Duda]

I've actually been working on writing code for processing dti data in 
ITK.  I've developed a DiffusionTensorPixel class as well as some code 
for IO, eigen decomposition, filters for calculation of various scalars 
(anisotropy, etc) and interpolators that incorporate various 
reorientation schemes.  I'd be happy to show you what I've got, although 
I'll probably need to clean it up a bit first.

-jeff
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Mon, 31 Jan 2005 22:26:26 +0000
> From: Torsten Rohlfing <torsten at synapse.sri.com>
> Subject: [Insight-developers] Suggestion: Tensors and Tensor Image
> 	Filters
> To: insight-developers at itk.org
> Message-ID: <41FEB092.4080509 at synapse.sri.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> Greetings!
> 
> It appears that there is not much functionality in ITK currently for 
> processing (MR diffusion) tensor data. I am therefore currently in the 
> process of writing such components myself.
> 
> Since I am planning to contribute the resulting code to ITK (if there is 
> interest), I wanted to ask for comments on some design decisions before 
> getting too far into the endeavour. Of course I would also be very 
> interest to hear whether this work has been done already (or is in 
> progress somewhere) and my efforts are, therefore, futile.
> 
> Most fundamentally in terms of design, I am unsure whether the basic 
> tensor processing operations (e.g., eigenvalues, eigenvectors, 
> potentially common anisotropy measures) should be implemented entirely 
> in image filter classes for tensor images (similar to the vector 
> gradient magnitude filters for example). It seems to me that a separate 
> tensor class would make sense to provide access to basic functions such 
> as eigensystem decomposition, which is useful for many tensor 
> operations, whereas the anisotropy measures for example should probably 
> go into filter classes.
> 
> Also, can anyone think of a reason why the tensor dimension (i.e., the 
> tensor matrix size) should be a template parameter (as opposed to fixed 
> 3x3)? My current state of mind is that tensor image dimensions should 
> definitely be templated to allow processing of 2D slices, whereas the 
> tensors themselves really don't seem to make much sense in anything 
> other than 3D.
> 
> Looking foward to comments and suggestions.
> 
> Best,
>   Torsten
>