[vtkusers] change contrast in volume object (it's too dark)

[Lisa Avila]

Hi,

First you need to determine why your image is dark. Is it dark because you 
are using shading and 1) don't have appropriate lighting parameters 
(ambient, diffuse, specular) or 2) don't have well-defined gradients in the 
data? Or, is it dark because your opacity function is too low and you are 
"seeing through" the whole volume (seeing mostly the background color)? Or 
is it dark because you have dark colors in your color transfer function? 
The solution is different depending on the reason for your dark image.

Lisa

At 09:33 AM 8/18/2005, powerhouseofexcellence wrote:
>Hi Amy,
>
>In principle it should just be a matter of:
>
>this->WindowLevel->SetInput(this->ImageData);
>this->VolumeMapper->SetInput(this->WindowLevel->GetOutput());
>
>I am afraid it will kill my machine to do window/level on the whole
>image data which probably has about 50 slices - when I try window
>leveling it will do the calculation for the whole image data container
>right? Are there any shortcuts or is this nothing to be concerned
>about?
>
>Thanks
>
>On 8/18/05, Amy Squillacote <amy.squillacote at kitware.com> wrote:
> > You should be able to use vtkImageMapToWindowLevelColors to do what
> > you want to do. The on-line documentation for that class is here:
> > 
> http://www.vtk.org/doc/nightly/html/classvtkImageMapToWindowLevelColors.html.
> >
> > - Amy
> >
> > At 11:01 PM 8/17/2005, powerhouseofexcellence wrote:
> > >Hello,
> > >
> > >I have a volume rendering going on, but the contrast of the volume is
> > >very poor, it's kind of difficult to see. Is there a way to implement
> > >a window/level function on the volume object? Or do I shift the values
> > >in my opacity/color transfer functions to create a window/level type
> > >effect?
> > >
> > >Thanks
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