[Insight-users] Gradient Vecotr Flow Snake in itk

[Pingkun Yan]

Hi, Xujf,

Hope the following code can help you. Rgds,


/************************************************************************/
/*  Convert itk mesh to vtk PolyData                                */
/************************************************************************/
void MeshToPolyData(MeshType* mesh, vtkPolyData* polydata)
{
  // Get the number of points in the mesh
  int numPoints = mesh->GetNumberOfPoints();
  if(numPoints == 0)
  {
    mesh->Print(std::cerr);
  }

  // Create the vtkPoints object and set the number of points
  vtkPoints* vpoints = vtkPoints::New();
  vpoints->SetNumberOfPoints(numPoints);

  // iterate over all the points in the itk mesh filling in
  // the vtkPoints object as we go
  MeshType::PointsContainer::Pointer points = mesh->GetPoints();
  for(MeshType::PointsContainer::Iterator i = points->Begin(); i != 
points->End(); ++i)
  {
    // Get the point index from the point container iterator
    int idx = i->Index();
    // Set the vtk point at the index with the the coord array from itk
    // itk returns a const pointer, but vtk is not const correct, so
    // we have to use a const cast to get rid of the const
    vpoints->SetPoint(idx, const_cast<FLOAT*>(i->Value().GetDataPointer()));
  }
  // Set the points on the vtk grid
  polydata->SetPoints(vpoints);

  // Now create the cells using the MulitVisitor
  // 1. Create a MultiVisitor
  MeshType::CellType::MultiVisitor::Pointer mv = 
MeshType::CellType::MultiVisitor::New();

  // 2. Create a triangle and quadrilateral visitor
  TriangleVisitor::Pointer tv = TriangleVisitor::New();
  QuadrilateralVisitor::Pointer qv =  QuadrilateralVisitor::New();

  // 3. Set up the visitors
  int vtkCellCount = 0;       // running counter for current cell being 
inserted into vtk
  int numCells = mesh->GetNumberOfCells();
  int *types = new int[numCells];  // type array for vtk
  // create vtk cells and estimate the size
  vtkCellArray* cells = vtkCellArray::New();
  cells->EstimateSize(numCells, 4);

  // Set the TypeArray CellCount and CellArray for both visitors
  tv->SetTypeArray(types);
  tv->SetCellCounter(&vtkCellCount);
  tv->SetCellArray(cells);

  qv->SetTypeArray(types);
  qv->SetCellCounter(&vtkCellCount);
  qv->SetCellArray(cells);

  // add the visitors to the multivisitor
  mv->AddVisitor(tv);
  mv->AddVisitor(qv);
  // Now ask the mesh to accept the multivisitor which
  // will Call Visit for each cell in the mesh that matches the
  // cell types of the visitors added to the MultiVisitor
  mesh->Accept(mv);

  // Now set the cells on the vtk polydata
  polydata->SetPolys(cells);

  // Clean up vtk objects (no vtkSmartPointer ... )
  cells->Delete();
  vpoints->Delete();
}

----- Original Message ----- 
From: "xujf" <xujf at sjtu.edu.cn>
To: <insight-users at itk.org>
Sent: Thursday, October 14, 2004 8:34 PM
Subject: Re: Re: [Insight-users] Gradient Vecotr Flow Snake in itk


> hello, Luis:
>
>     In the examples you descriped, I only find the tranformation from 
> itkSimplexMesh to vtkPolyData
> and the transformation from itkMesh to vtkUnstructedGrid. the method that 
> transforms itkMesh to vtkPolyData is not found.  Is there any method that 
> transforms itkMesh to vtkPolyData?
>
>     I just tried to translate my semgmentation result which is itkMesh to 
> vtkUnStructedGrid (according the example 
> InsightApplications/Auxiliary/vtk/vtk2itk.cxx),then I  visulize the 
> result. however the result is very bad, and the surface of the result is 
> not smooth.
>
>    my ultimate aim is to realize tranditional snake or GVF snake. I wonder 
> whether ITK provider such
> classes to realize it?
>
> Best Regards!
> xujf
>
> ----- Original Message -----
> From: Luis Ibanez <luis.ibanez at kitware.com>
> To: xujf at sjtu.edu.cn
> Cc: Insight-users at itk.org
> Subject: Re: [Insight-users] Gradient Vecotr Flow Snake in itk
>
>
> Hi Xujf
>
> You will find multiple examples on how to convert an ITK
> itk::Mesh in to a VTK vtkPolyData in the directory
>
>          InsightApplications/Auxiliary/vtk
>
>
> you will also find an example on this in the demo application
>
>
>   InsightApplications/DeformableModelSimplexMesh
>
>
>
> Regards,
>
>
>   Luis
>
>
> -------------------
> xujf wrote:
>
>> Hello,Luis:
>>    According the 
>> example:Insight/Examples/Segmentation/DeformableModel1.cxx,I wrote my 
>> code in vc++.
>> In order to visilize the segmenatation result, I have to transform 
>> itkMesh (itk::DeformableMesh3DFilter->GetOutput()) to vtkPolyData. I 
>> wonder how to realize the transformation.
>>
>> Best Regards!
>> xujf
>> ----- Original Message -----
>> From: Luis Ibanez <luis.ibanez at kitware.com>
>> To: xujf at sjtu.edu.cn
>> Cc: insight-users at itk.org
>> Subject: Re: [Insight-users] Gradient Vecotr Flow Snake in itk
>>
>>
>> Hi Xujf,
>>
>> Please look at the examples:
>>
>>
>>    Insight/Examples/Segmentation/
>>                        DeformableModel1.cxx
>>                        DeformableModel2.cxx
>>
>>
>> The classes in ITK that implement deformable models
>> on the "Snake" family are:
>>
>> A)
>> http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableMesh3DFilter.html
>>
>> B)
>> http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableSimplexMesh3DBalloonForceFilter.html
>>
>>
>>
>> (A) uses a classical triangulation mesh
>>
>> (B) uses a Simplex mesh, contributed by Thomas Bottger of
>>     the MBI group at the German Cancer Research Center (DKZF).
>>
>>
>>
>> You will find a demo application using (B) (the simplex mesh) under
>>
>>       InsightApplications/
>>                DeformableModelSimplexMesh
>>
>>
>> This application was contributed by Leila Baghdadi from the Mouse
>> Imaging Center (MICE) at the Hospital for Sick Kids in Toronto.
>> This application will require you to intall VTK and FLTK.
>>
>> Note that deformable models are quite sensitive to the parameter
>> settings, so be prepared to be patient when fine tunning those
>> parameters.
>>
>>
>>
>>   Regards,
>>
>>
>>      Luis
>>
>>
>>
>> -------------------
>> xujf wrote:
>>
>>
>>>hello,everyone:
>>>    how to realize GVFS(Gradient Vecotr Flow Snake) segmentation. which 
>>> itk classes I should use ?
>>>
>>>Thanks in advance!
>>>xujf
>>>
>>>
>>>------------------------------------------------------------------------
>>>
>>>_______________________________________________
>>>Insight-users mailing list
>>>Insight-users at itk.org
>>>http://www.itk.org/mailman/listinfo/insight-users
>>
>>
>>
>>
>>
>>
>>
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