[vtkusers] Re: vtkImageData & tensors & filters

[Alexandre Guimond]

On Thu, 28 Jun 2001 04:20:37 -0400 (EDT)
David Gobbi <dgobbi at irus.rri.ca> writes:

> Hi Alexandre, Christina:
> 
> I don't think that anything apart from perhaps some new imaging
> filters is required to support tensor images.  Most of the
> existing filters will already accept any number of components
> per pixel, so you just need to use images with 6 (or is it 9?)
> components as needed to describe the tensor.

I though scalars were restricted to 4 chanels.  Did that change?

> No changes to vtkImageSource should be necessary, as far as I can
> see, as long as >4 components are already properly supported.

So I guess it is new.  Wonderful!

> Could you make a list of operations you'll need to be supported for
> tensors?  I'm not one of the 'vtk folks' but I can probably offer
> some advice re: implementation.

I don't have an exaustive list now.  I'm just starting to play with
it.  For the moment I do need math operators "+", "-", and composition
with tensors, and "*" and "/" with scalars, and something similar to
vtkImageShrink.  At some point I'll also need something similar to
vtkImageReslice that would reorient tensors aswell as move them
according to a given transformation.  For non-rigid transforms, it
should also be able to modify the tensor appropriatly.  I don't really
know yet what that implies in details; I'll have to figure it out at
some point.

If it's true with the 4 chanels thing, the parts missings are tensor
composition and the vtkImageReslice.
-- 
Alexandre Guimond, Ph.D. guimond at bwh.harvard.edu Phone:(617) 278-0800 
http://spl.bwh.harvard.edu:8000/~guimond/          Fax:(617) 264-5154
Brigham and Women's Hospital, Harvard Medical School
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