[vtkusers] picking from a resliced image

[Greg Book]

I'm using the vtkImagePlaneWidget to create arbitrarily resliced planes
and I'm displaying the new plane as a vtkImageActor. I can do picking on
the imageactor, but it doesn't give the correct 3D location in the
volume data from which i can extract an intensity at that location. Does
the imageactor give the picker access to the full 3D volume, or only the
2D resliced plane?

Basically, how can I do picking on a resliced image?

-Greg