[vtk-developers] Incorrect color function in vtkImageMapToWindowLevelColors with lookupTable

[David Gobbi]

Hi Victor,

I have updated the vtkImageMapToWindowLevelColors documentation according
to my understanding of how it works:
https://www.vtk.org/doc/nightly/html/classvtkImageMapToWindowLevelColors.html
Honestly I think the class would be better without the "color modulation"
feature.  If you are displaying grayscale, you can use the class without a
lookup table.

It might be possible to set GL_UNSIGNED_INT_2_10_10_10_REV in VTK if you
make your own frame buffer object, but you can't use it with any of the
usual image viewers or image mappers that are already in VTK, since they
all assume 8 bits per color component for the display.  The luminance via
RGB trick should work fine if you have a suitable grayscale monitor with
RGB input.

 - David



On Tue, May 29, 2018 at 3:21 AM, xVict <suharev at roentgenprom.ru> wrote:

> Hi David,
>
> To test the vtkImageMapToWindowLevelColors class the sources was uploaded
> on
> GitHub:
> https://github.com/xThorn/vtk-tests
> See mapToWLC folder.
>
> By first item: can I set texture type GL_UNSIGNED_INT_2_10_10_10_REV?
>
> In https://www.vtk.org/Wiki/VTK/Image_Rendering_Classes
>
> Many greyscale monitors with DVI inputs use the equation L = 0.30*R +
> 0.59*G
> + 0.11B to convert the 24-bit RGB DVI signal into a greyscale signal. For
> such monitors, it is possible to create a vtkLookupTable with 4096 entries
> that provides distinct greyscale values via appropriately-chosen RGB
> values.
>
> This method works through GDI.
>
> Victor.
>
>
>
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