[vtkusers] How to stop blurring between images when volume rendering an imag e stack.

[Lisa Avila]

Hi Rupert,

It seems the "feature" you like is actually one of the shortcomings of 2D 
texture mapping - seeing the space between slices from some view angles 
because interpolation is only performed in 2D, not 3D.

Volume rendering assumes you have a field of data defined over some 3D 
space, with an interpolation function that can be used to compute values in 
between sample points. The software rendering method allows for two 
different interpolation functions: trilinear and nearest neighbor. The 2D 
texture mapper only allows for bilinear in the plane in which the textures 
are created (this changes depending on your viewing direction).

I suspect what you want to see are the actual slices stacked on top of each 
other - for this I would recommend texture mapping each image only a 
polygon. You'll need to ensure that they are rendering in the correct 
order, which the view frustum culler may be able to do for you.

Lisa


At 06:39 AM 2/20/2004, Rupert Shute wrote:
>
>Hello,
>
>Does anyone know how I can stop the blurring effect between images in a
>stack when volume rendering? The images are required to have a relatively
>large, empty, gap between them. If I use a vtkVolumeTextureMapper the
>desired effect is achieved from certain viewing angles. However, I need this
>from all viewing angles. It would also be nice if I could achieve the same
>effect using software rendering.
>
>Any ideas, or am I asking the impossible?
>
>Cheers
>
>Rupert
>--
>_______________________________________________________________________________
>
>The information in this email and in any attachment(s) is commercial in 
>confidence. If you are not the named addressee(s) or if you receive this 
>email in error then any distribution, copying or use of this communication 
>or the information in it is strictly prohibited.  Please notify us 
>immediately by email at intadmin at awe.co.uk, and then delete this message 
>from your computer.  While attachments are virus checked, AWE plc does not 
>accept any liability in respect of any virus which is not detected.
>
>_______________________________________________
>This is the private VTK discussion list.
>Please keep messages on-topic. Check the FAQ at: 
><http://public.kitware.com/cgi-bin/vtkfaq>
>Follow this link to subscribe/unsubscribe:
>http://www.vtk.org/mailman/listinfo/vtkusers