[vtkusers] Extracting one component from a color image

[Pierre Barbier de Reuille]

Hello,

I have 3D images saved in PNG file format. The images are in shades of
grey only. The PNG reader outputs a vtkImageData with 3 components. That
makes perfect sense to me, and I don't see how it could be otherwise.
However, my data are really linear and I just don't see how I can
extract one of the channels (for now I don't care which as they are all
the same).

Thanks,

Pierre