[Insight-users] using ImageToVTKImageFilter for multiple WindowRenderer

[snrf at no-log.org]

Hello Luis (and already thanks for the previous tip on vtkImagePlaneWidget:

All my code is in c++/VTK5.0/ITK3.2/Linux fedora 7.

What I want to achieve is to create one caster (casted image) per reader
(loaded dataset), and then be able to use them in any ITK/VTK pipeline.
Where my reader is a table of pointer right now, my caster is not and I
feel this is the problem. However, I tried to change my caster pipeline to
have a table of caster but each time I try to display 2 casted input
images in two different renderers I have a crash.

Originally, I used VTK a lot and I think I have a lack of understanding of
ITK's pipeline with regards to memory allocation and pointers specially.

Getting to my code:

My function that actually casts the ITK inputs is as follows -
void File::CastMIP(int DataID)
{

	//create cast filter to cast inputImage into output image data
	typedef itk::MinimumMaximumImageCalculator< ImageType >
MinMaxCalculatorType;
MinMaxCalculatorType::Pointer calculator = MinMaxCalculatorType::New( );
	calculator -> SetImage( reader[DataID]->GetOutput() );
	calculator->ComputeMaximum();
	calculator->ComputeMinimm();
	ImageType::PixelType minIntensity = calculator->GetMinimum();
	ImageType::PixelType maxIntensity = calculator->GetMaximum();

	Original_Min_Intensity = minIntensity;
	Original_Max_Intensity = maxIntensity;
	typedef itk::RescaleIntensityImageFilter< ImageType, MIPImageType >
RescaleFilterType1;
	RescaleFilterType1::Pointer caster1 = RescaleFilterType1::New();
	caster1->SetInput( reader[DataID]->GetOutput() );
	caster1->SetOutputMinimum(   0 );
	caster1->SetOutputMaximum( (int) maxIntensity + abs(minIntensity) );
	caster1->Update();
	//caster1->SetReleaseDataBeforeUpdateFlag(TRUE);
	///////////// ITK - VTK Connection //////////////
	connector = ConnectorType::New();
	connector->SetInput(caster1->GetOutput());
	connector->Update();
}

Here reader refers to a function that just read (who'd guess) data - each
new set of data being loaded in a table of reader indexed by DataID, and
as follows -

void File::Load3D(QWidget* Window)
{

	/*			ITK pipeline to load images			*/


	typedef itk::GDCMSeriesFileNames                NamesGeneratorType;
	typedef std::vector< std::string > SeriesIdContainer;
	typedef std::vector< unsigned int> NumSeriesFilesContainer;
	typedef std::vector< std::string > FileNamesContainer;
.............. usual ITK code to read dicom files ..........
try
	{

	reader[DataLoaded.NbDataLoaded] = ReaderType::New();
	reader[DataLoaded.NbDataLoaded]->SetImageIO( gdcmIO );
	reader[DataLoaded.NbDataLoaded]->SetFileNames( fileNames );
	reader[DataLoaded.NbDataLoaded]->Update();

	}
}

- here DataLoaded is a global structure that keeps tracks of every input
and output information.

Finally, my call to the caster is done, for example, in the MIP rendering
function as follows -
 void ThreeDRendering::DisplayMIP(int TabID)
 {

........... usual VTK code here .........
volumeMapper->SetInput( FileAction->connector->GetImporter()->GetOutput()  );
	   volume->SetMapper( volumeMapper );
	   volume->SetProperty( mipProperty );
		ren3DMain->AddVolume(volume);
	   ren3DMain->ResetCamera ();
	   ren3DMain->ResetCameraClippingRange ();
	   renWin3DMain->Render();
}

Here, FileAction is the object of type FILE that handles, amongst others,
the reader and caster., The renderers are not directly set within this
context, but set in the core program (the main one) and each time a new
object is created it has an internal function that does set the pointers
toward the renderers created in the main program, - as follows -

void SetPrt(vtkRenderer *ren3DMainptr, vtkRenderWindow *renWin3DMainptr, 
vtkRenderWindowInteractor *iren3DMainptr,
	File	*FileActionptr)
	{
		ren3DMain = ren3DMainptr;
		renWin3DMain = renWin3DMainptr;
		iren3DMain = iren3DMainptr;
		FileAction = FileActionptr;
	};


Thanks for your help.
Flo.

>>
>> Hi Flo,
>>
>> Please post the the list the following:
>>
>> 1) The declaration of your void function
>> 2) The lines where you call the function
>> 3) The declaration of your ITK image and vtkImageData
>>    outside of the function.
>>
>> BTW: Are you programing in C++ ?
>>
>> Are you instantiating the RenderWindow outside of the void function ?
>> or inside ?
>>
>>
>>   Please let us know,
>>
>>
>>      Thanks
>>
>>
>>        Luis
>>
>>
>> ---------------
>> Flo wrote:
>>> Dear all:
>>> I'm using a void function containing ImageToVTKImageFilter in
>>> conjunction with a Caster to pass images from ITK to VTK.
>>> Everything works fine in the case where I use a single
>>> WindowRender/ Renderer.
>>> However, If I have 2 or more WindowRenders, and if each has a
>>> different call to my function (with different input images) then
>>> I  have a segmentation fault.
>>> To my understanding, this is a memory access violation due to the
>>> "pointer" strategy of ITK while creating the Casting/Exporting
>>> pipeline.
>>> Thus, I tried different update(), updatewholeextent() calls but
>>> in  vain (I thought it would have force the ITK pipeline to create
>>> a new  pointer - now I understand why this was a bad guess !!!).
>>> So here is my question, is creating such a function but returning
>>> a  pointer to the casted data the best way to do things ? But
>>> then, how  to make sure I really have a new pointer towards my new
>>> casted data ?  I tried to declare a table of connector
>>> (ImageToVTKImageFilter  connectors) but it failed as well !
>>> any suggestions would be of great help.
>>> Flo.
>>> _______________________________________________
>>> Insight-users mailing list
>>> Insight-users at itk.org
>>> http://www.itk.org/mailman/listinfo/insight-users
>
>