[Insight-users] Multi-threading a filter

[Jack Lee]

Hi there,

I am trying to implement a multithreaded version of the 
itkHessian3DToVesselnessMeasureImageFilter.hxx. To do this, I've 
followed these steps (sorry it's a bit messy):

1) Created
ThreadedGenerateData(const OutputImageRegionType &region, ThreadIdType 
threadId)

2) changed the iterators' second parameter from

it = ImageRegionConstIterator< EigenValueOutputImageType >(
eigenImage, eigenImage->GetRequestedRegion() );

to

it = ImageRegionConstIterator< EigenValueOutputImageType >(
eigenImage, region );

and similarly with

oit = ImageRegionIterator< OutputImageType >( output, region );

3) commented out the line    this->AllocateOutputs();


This code segfaults, sometimes with error messages indicating that 
ImageConstIterator is trying to access indices outside the buffered 
region, and other times just with a silent core dump. If anybody can 
explain to me what is wrong with the changes made above (or, indeed 
steps I might have missed out) I'd appreciate it very much.

Best wishes,
Jack