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

[Karthik Krishnan]

Jesse C Cronce wrote:

>If you do a DisconnectPipeline, that will also disconnect memory
>management of the image from the ITK libraries as well, right ? 
>
Not if you use smart pointers. (Memory management should be taken care 
of) For instance, this is ok if you had

filter->Update();
ImageType::Pointer x = filter->GetOutput();
x->DisconnectPipeline();

this is not ok.

filter->Update();
ImageType* x = filter->GetOutput();
x->DisconnectPipeline();

The reference count is needed to prevent x from getting destroyed.

>(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 ?
>
>  
>
yes

>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
>>> 
>>> 
>>>
>>>------------------------------------------------------------------------
>>>
>>>_______________________________________________
>>>Insight-users mailing list
>>>Insight-users at itk.org
>>>http://www.itk.org/mailman/listinfo/insight-users
>>> 
>>>
>>>      
>>>
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>>
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