AW: [Insight-users] Snake?, Yes

[Waltraud Henrich]

Hi,

 I would like to use "deformablemesh3Dfilter" but I am not sure how to 
do this.
I am working with VTK (vtkImageData). First I connect my VTK pipeline to an
ITK 
pipeline, with vtkImageExport -> itk::VTKImageImport for VTK->ITK and 
at the end itk::VTKImageExport -> vtkImageImport for ITK->VTK.
After the first connection I used ImageToMeshFilter for to get a mesh.
The next step was that I used the GradientImageFilter, then the
DeformableMesh3DFilter.
My question now are:
- how can I use the DeformableMesh3DFilter in a corrct way ?
- how exactly is the DeformableMesh3DFilter working ?
- and then I would like to know if the way I used the filters was right 

I add my code

//VTK->ITK

	vtkImageExport* vtkExporter = vtkImageExport::New();
	vtkExporter->SetInput(pImage);
	
	
	
//------------------------------------------------------------------------
	// VTK to ITK pipeline connection.
	
//------------------------------------------------------------------------
	
	typedef itk::Image<short, 3> ImageType;
	typedef itk::Image<unsigned long, 3> ImageTypeULONG;
	typedef itk::VTKImageImport<ImageType> ImageImportType;
	ImageImportType::Pointer itkImporter = ImageImportType::New();
	ConnectPipelines(vtkExporter, itkImporter);
	


	typedef itk::Mesh<short, 3> MeshType;
	itk::ImageToMeshFilter<ImageType, MeshType>::Pointer
		mesh = itk::ImageToMeshFilter<ImageType,MeshType>::New();
	mesh->SetInput(0,itkImporter->GetOutput());
	mesh->Update();
  


	typedef itk::GradientImageFilter<ImageType, short, short>
FilterType;
    typedef FilterType::OutputImageType OutputImageType;
      
      // Set up filter
    itk::GradientImageFilter<ImageType, short, short>::Pointer 
      filter = itk::GradientImageFilter<ImageType, short, short>::New();

	double m_stiff[2];
	double m_scale[3];
	m_stiff[0]=0.00001;
	m_stiff[1]=0.04;
	m_scale[0] = 2;
	m_scale[1] = 2;
	m_scale[2] = 2;

	
	itk::DeformableMesh3DFilter<MeshType, MeshType>::Pointer 
	m_bfilter= itk::DeformableMesh3DFilter<MeshType, MeshType>::New();
	m_bfilter->SetStiffness(m_stiff);
	m_bfilter->SetTimeStep(0.2);
	m_bfilter->SetStepThreshold(1);
	m_bfilter->SetScale(m_scale);
	m_bfilter->SetGradient(filter->GetOutput());
	m_bfilter->SetInput(mesh->GetOutput());
	m_bfilter->Update();
	
  
 
	
//------------------------------------------------------------------------
	// ITK to VTK pipeline connection.
	
//------------------------------------------------------------------------
		  
	typedef itk::VTKImageExport<ImageTypeULONG> ImageExportType;	
		  
	ImageExportType::Pointer itkExporter = ImageExportType::New();
	itkExporter->SetInput(m_bfilter->GetOutput());

		  
		  
		  
		  
	// Create the vtkImageImport and connect it to the
itk::VTKImageExport instance.
	vtkImageImport* vtkImageImport = vtkImageImport::New();  
	ConnectPipelines(itkExporter, vtkImageImport);
		  
	vtkImageImport->Update();
		  
		  
	vtkImageData* pResultImage = vtkImageImport->GetOutput();
		 
	vtkImageData* pNewResultImage = vtkImageData::New();
	pNewResultImage->DeepCopy(pResultImage); 


	GfxPlaneViewer(pNewResultImage, "snake");




I want to thanks for your help in advance.
Yours sincerely

Waltraut Henrich


-----Originalnachricht-----
Von: Luis Ibanez
An: Waltraud Henrich
Cc: 'insight-users@public.kitware.com'
Gesendet: 04.11.02 15:05
Betreff: Re: [Insight-users] Snake?,   Yes


Hi Waltraud,

There are several flavors of active contours in ITK.

1) The  first is the traditional expanding Mesh
    controled by a force with a constant component
    and an image derived component.

This approach is implemented by Dr.Metaxas group
in the classes:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableMeshFilter
.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableMesh3DFilt
er.html


2) The second approach is based on Level Sets.
    The surface is represented as the level set
    of a function in a higher dimensional space.

The evolution of the function under differential
equations determines the evolution of the embebded
surface. This is implemented in the GeodesicActiveContour
class:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1GeodesicActiveContou
rImageFilter.html


3)  Similar effects can be obtained in general with
     level sets approached. You may want to consider the
     ThresholdSegmentation filter:
 
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ThresholdSegmentatio
nLevelSetImageFilter.html

and the LaplacianSegmentation filter:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1LaplacianSegmentatio
nLevelSetImageFilter.html


Please let us know if you have any question about
the use of these classes.



Thanks


    Luis



===========================================
Waltraud Henrich wrote:
> 
> Dear users, 
> 
> I am new to ITK and  I have a question . Is there something to program
in
> ITK around Active Contour Models (or snakes) ? 
> 
> thank for the help. 
> 
> Waltraut.
> _______________________________________________
> Insight-users mailing list
> Insight-users@public.kitware.com
> http://public.kitware.com/mailman/listinfo/insight-users
> 
>