[vtkusers] Problem with vtkLookupTable

[Miguel Sotaquira]

Hi Sandra,

Maybe you have to rescale your image (using vtkImageShiftScale) after
resampling with vtkResample, so as to ensure that pixels' type is unsigned
char.

Miguel

On Fri, Mar 30, 2012 at 6:23 PM, Hikaruchan
<Sandra.Schroetter.fl at ait.ac.at>wrote:

> Hi everyone!
>
> I have a little Problem with my vtkLookupTable, and I don't know why. I
> have
> a Lookuptable with 256 colors, but after rendering my actor it seems that
> the image which is rendered to the screen and was mapped through the
> lookuptable only something about eight colors (it only looks like that).
> And
> I don't get it, where I make my mistake. Hope you can help me or give me a
> hint.
>
> I have attached two images. The first one (HowItIsNow.jpg), shows the
> actual
> result. You can see that it seems, that there are not 256 colors.
>
> http://vtk.1045678.n5.nabble.com/file/n5607138/HowItIsNow.jpg
>
> The second one (HowIWouldLikeIt.jpg) shows the result, which I want to
> have.
> The two images are based on the same data, the second is a result in MATLAB
> the first in VTK. Maybe you can give me a hint how to get the image in VTK
> like the second image shown (done in Matlab).
>
> http://vtk.1045678.n5.nabble.com/file/n5607138/HowIWouldLikeIt.jpg
>
> My Pipeline is as follows:
>
> vtkImageData -> filled via frequencyDataIma->GetScalarPointer() with
> unsigned char
> vtkLookupTable -> 256 colors
> vtkResample -> for resizing the image (make it bigger)
> vtkImageMapToColors -> the lookuptable is applied to it and the
> resample->Output() is the Input for it
> vtkImageMapper -> Input is the Output of the vtkImageMapToColors
> vtkActor2D -> input is the mapper
>
>
>
> Greets
>
> Sandra
>
> --
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