[vtkusers] Iterative Imaging Filter: DeepCopy / Extent problems

[Sven Prevrhal]

I'd need help with the following:

I want to do an iterative image filter (grayscale morphologic
reconstruction), so the output of the filter chain needs to go in the input
again. I guess I have to copy the output vtkImageData into a new input
vtkImageData object. So I do (in Tcl)

...
vtkImageData input($i)
input($i) DeepCopy output([expr $i-1])
...
-filter chain-
...

It seems I can't get the Extent methods right. When I have input($i) in a
vtkImageViewer, then ouput($iminus1) GetExtent gives 0 63 0 63 3 3 when the
viewed slice is number 3. After the DeepCopy, input($i) GetExtent is ..3 3
as well, and points outside this slice always give 0 with
GetScalarComponentAsFloat!! 

I tried various combinations of SetExtent, SetUpdateExtent and
SetWholeExtent on both input and output before the DeepCopy, no help.
Sometimes the app even crashes after that when I want to view a new slice.

What do I need to do??

:-) sven
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