[vtkusers] Applying different transfer functions to even/odd slices

[Lisa Avila]

Hi Rita,

Please keep this discussion on the mailing list.

You should be able to create a blank image from one of your existing images 
- just threshold it to set all values in it to a constant value (you'll 
need to determine what that value should be). Then you can use 
vtkImageAppend repeatedly to append a "real" slice, then a "blank" slice, 
then a "real" slice, etc. Do the same thing again into another volume, 
starting with a "blank" slice, then a "real" slice, etc. Then use 
vtkImageAppendComponents to put the two volumes together into one.

Lisa



At 07:50 PM 5/31/2005, rywchiu wrote:
>Hi Lisa,
>
>Thanks for your reply! I'm now wondering how you can insert "blank" slices 
>between even/odd slices.
>
>So far I have tried using vtkExtractVOI; however that gives me a compacted 
>version of my original volume containing only the even or odd slices, 
>without any spacing between slices. Any way I can put in blank slices in there?
>
>I've also tried ImageReslice and ImageAppend, and I get the same results. 
>I can probably add a blank image with slice dimensions in between each 
>even/odd slice, but I'm not sure how to create this blank image. Any 
>suggestions?
>
>Thanks again,
>
>Rita
>
>
>
>-----Original Message-----
>
> > Date: Tue May 31 07:12:33 PDT 2005
> > From: "Lisa Avila" <lisa.avila at kitware.com>
> > Subject: Re: [vtkusers] Applying different transfer functions 
> to  even/odd slices
> > To: "rywchiu" <rywchiu at interchange.ubc.ca>, vtkusers at vtk.org
> >
> > Hello Rita,
> >
> > Currently VTK supports only one set of transfer functions per component of
> > your volume, and only supports multiple volumes that do not overlap. If 
> you
> > use the vtkFixedPointVolumeRayCastMapper which supports multiple
> > components, you could break your odd and even slices out into separate
> > components (using twice the memory though - you would need to insert
> > "blank" slices in each component in between the "real" slices) and give
> > each a separate transfer function.
> >
> > Lisa
> >
> >
> > At 02:58 PM 5/27/2005, rywchiu wrote:
> > >Hi,
> > >
> > >I want to be able to apply different colour transfer functions for even
> > >and odd slices of a 3D volume. The data that is being read is a MetaImage
> > >with a single raw file. How could you go about doing this?
> > >
> > >Would I have to read even slices separately from odd slices? And does
> > >vtkImageReader2::SetFileNameSpacing() work for a single raw file? And if
> > >I'm reading even/odd slices separately, is it possible to output them 
> back
> > >together (after giving them different transfer functions) within the same
> > >volume?
> > >
> > >Any suggestions are greatly appreciated!
> > >
> > >Thanks,
> > >Rita
> > >
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