[vtkusers] Convert ITK image to VTK volume keeping proper orientation and position

[David Doria]

2011/7/5 Dženan Zukić <dzenanz at gmail.com>:
> I hope this function can save someone a lot of time and headaches. It takes
> an itk::Image and converts it into a vtkVolume, keeping it in DICOM's
> patient physical world space. Its main usage is combining it with segmented
> structures (vtkPolyData) whose vertices are in DICOM patient space, that is,
> vertex coordinates were obtained using
> visualizing->TransformIndexToPhysicalPoint().
> typedef itk::Image<unsigned char, 3> VisualizingImageType
> void showITKimageInVTKqwidget(VisualizingImageType::Pointer visualizing)
> {
>     typedef itk::ImageToVTKImageFilter<VisualizingImageType>
> itkVtkConverter;
>     itkVtkConverter::Pointer conv=itkVtkConverter::New();
>     conv->SetInput(visualizing);
>
>     vtkGPUVolumeRayCastMapper *mapper = vtkGPUVolumeRayCastMapper::New();
>     mapper->SetInput(conv->GetOutput());
>     vtkVolume *volume=vtkVolume::New();
>     volume->SetProperty( myTransferFunction );
>     volume->SetMapper( mapper );
>     // vtkVolume only manages spacing by itself.
>     // Here we take care of position and orientation so it is in DICOM
> physical space
> VisualizingImageType::DirectionType d=visualizing->GetDirection();
> vtkMatrix4x4 *mat=vtkMatrix4x4::New(); //identity matrix
> for (int i=0; i<3; i++)
> for (int k=0; k<3; k++)
> mat->SetElement(i,k, d(i,k));
> VisualizingImageType::PointType origin=visualizing->GetOrigin();
> volume->SetOrigin(-origin[0], -origin[1], -origin[2]);
> volume->SetPosition(-origin[0], -origin[1], -origin[2]);
> for (int i=0; i<3; i++)
> mat->SetElement(i,3, origin[i]);
> volume->SetUserMatrix(mat);
>     vtkRenderer *renderer =
> myQWidget->GetRenderWindow()->GetRenderers()->GetFirstRenderer();
>     renderer->AddVolume( volume );
>     myQWidget->GetRenderWindow()->Render();
>     renderer->ResetCamera();
> }
>
> Dženan

Dženan,

Thanks for sharing. I would put something like this on the examples
wiki in a section called "Bridge" or "Glue" or something like that
(these are names that have been previously used to describe
interactions between ITK and VTK). This will make it much easier to
find in the future instead of having to dig through old mailing list
archives.

David D.