[Insight-users] VTK - ITK - VTK Pipeline problems

[Jesse C Cronce]

If you do a DisconnectPipeline, that will also disconnect memory
management of the image from the ITK libraries as well, right ? (meaning
that the memory will have to be deleted/freed when no longer in use)
Also, if you call a GetOutput() on the filter that has been disconnected
from the pipeline, it looks like the result should be a NULL pointer
(from the code itkDataObject.cxx - 

    m_Source->SetNthOutput(m_SourceOutputIndex, 0);

) is this also correct ?

Thanks!
JCC

On Mon, 2005-10-31 at 10:53 -0500, Karthik Krishnan wrote:
> Did you try to disconnect the objects from teh pipeline ?
> 
> In ITK:
> 
> filter->Update();
> itkImage = filter->GetOutput();
> itkImage->DisconnectPipeline();
> 
> In VTK:
> 
> use UnRegisterAllOutputs() to disconnect the pipeline
> or use ShallowCopy
> 
> 
> 
> Istvan Matis wrote:
> 
> > Hello ITK users,
> >  
> > I am using a complex pipeline to convert vtkImageData to itk Image, 
> > apply some filters on it (each time a different filter) like 
> > smoohting, segmentation, then convert back to VTK in order to 
> > visualize it.
> > My problem is that I receive various errors, "unhandled exceptions" 
> > sometimes in the itk sources sometimes in system dlls, usually when I 
> > want to apply the itk filters for the 2nd time.
> >  
> > I am using the same pipeline several times on several (different) 
> > images read into VTK.
> > As I understood, if one element (object) in the VTK->ITK->VTK pipeline 
> > is destroyed the whole pipeline will crash. In order to prevent this I 
> > use vtkImageCast to "Clone" the final vtk output in order to separate 
> > the output vtkImageData from the whole pipeline.
> >  
> > Here is the sketch of the pipeline:
> >  
> > vtkImageData Input ->
> > -> vtkImageCast ->
> > -> vtkImageData Input 2 ->
> > -> itk::VTKImageToImageFilter ->
> > -> itk::Image ->
> > -> " different itk filter each time: ex: 
> > itk::ConnectedThresholdImageFilter or itk::CurvatureFlowImageFilter " ->
> > -> itk::Image Output ->
> > -> itk::ImageToVTKImageFilter ->
> > -> vtkImageData Output ->
> > -> vtkImageCast ->
> > -> vtkImageData Output 2
> >  
> > I use ->Update() at every step!
> >  
> > By the way I am using itk 2-0-0, vtk 4-4, VC++6 with SP6, WinXP Pro.
> >  
> > Is a solution to recreate (Delete() and New()) all the itk and vtk 
> > filters in the pipeline each time they need to be used? I observed 
> > that if I destroy even one of these filters the whole thing crashes, 
> > and not immediately, but sooner or later, somewhere when vtk needs the 
> > data.
> >  
> > My question is:
> > How can I separate the resulting vtkImage from the whole vtk-itk-vtk 
> > pipeline once it was processed?
> > Or more generally:
> > How can I reuse the whole pipeline on different images with different 
> > sizes and attributes?
> >  
> > Any hints will be gratefully apreciated.
> >  
> > Sincerelly,
> > Istvan
> >  
> >  
> >
> >------------------------------------------------------------------------
> >
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> >  
> >
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