[vtkusers] Thresholding with Transparency

[Ben Wilde]

Hello,

I am very, very new to VTK, and I'm trying to do some video processing that 
I don't imagine should be too complicated.

I have some video data that I would like to apply a threshold to, in which 
only the image above the threshold appears, and the non-thresholded sections 
are transparent.

I am using am using video.getOutput to turn my video into an image.  I have 
looked at using vtkImageThreshold, but I can't figure out how to make the 
thresholded parts of the image transparent.  Am I missing something easy?  
If not, does anybody have suggestions on how to proceed?

I apologize if this is too easy or if I misused any terminology.  Again, I'm 
am about as much of a beginner as you can be.

Thank you,
Ben