[vtkusers] how to brighten an image?

[Wolfram H Volpi]

I have an image that is very dark, almost all black.

Is there a vtkImage filter that will multiply the pixel values
by a constant?

vtkImageToImageFilter might be the thing to use, but it has no
documentation, or tcl example.  How does it work?

Does any one have a suggestion on how to brighten up an image?

Thank you,
Wolfv.