[Insight-users] Problem with watersheds segmentation

[Sotiris Dimopoulos]

Hi!
I use watersheds for the segmentation of a ct slice
(of a simple bone) which is in jpeg format, and in the
vtk window in which i see my results...i get
nothing...( as if my program found nothing to segment)

I,m also a bit confused with the parameters..For
example what parameter do i set in the function
SetUsePrincipleComponents() of the
GradientMagnitudeImageFilter class??

I'm sending tyou the code in case something else goes
wrong...

Thanks in advance

Sotiris


int main( int argc, char *argv[])
{
  


// types of data

  typedef   float           InternalPixelType;
   const     unsigned int    Dimension = 2;
  typedef itk::Image< InternalPixelType, Dimension > 
InternalImageType;
 

  typedef unsigned char OutputPixelType;
  typedef itk::Image< OutputPixelType, Dimension >
OutputImageType;
 
  

  // We instantiate reader 
 
  typedef  itk::ImageFileReader< InternalImageType >
ReaderType;
  
  ReaderType::Pointer reader = ReaderType::New();
 
  reader->SetFileName( "C:/Documents and
Settings/sotiris/Desktop/OSTA/osta
3,5/JPEG/Img0108.jpg" );
 
 
 // use the cast filter


  typedef itk::CastImageFilter<InternalImageType ,
OutputImageType>
    CastingFilterType;
  CastingFilterType::Pointer caster =
CastingFilterType::New();
                        


 // Extract the roi

	typedef itk::RegionOfInterestImageFilter<
InternalImageType,InternalImageType > FilterType;
 
	 FilterType::Pointer regionfilter =
FilterType::New();

  InternalImageType::IndexType start;
  start[0] =  220 ;
  start[1] =  220 ;

  InternalImageType::SizeType size;
  size[0] =  120 ;
  size[1] =  120 ;

  InternalImageType::RegionType desiredRegion;
  desiredRegion.SetSize(  size  );
  desiredRegion.SetIndex( start );

  regionfilter->SetRegionOfInterest( desiredRegion );

  

  //  The filters for the image.
  
  typedef
itk::GradientAnisotropicDiffusionImageFilter<InternalImageType,
    InternalImageType>  DiffusionFilterType;

  typedef
itk::GradientMagnitudeImageFilter<InternalImageType,InternalImageType>
    GradientMagnitudeFilterType;
  
  typedef itk::WatershedImageFilter<InternalImageType>
WatershedFilterType;


// The diffusion filter 

  DiffusionFilterType::Pointer diffusion =
DiffusionFilterType::New();
  diffusion->SetNumberOfIterations( 5 );
  diffusion->SetConductanceParameter( 3.0 );
  diffusion->SetTimeStep(0.125);

  // The ITK gradient magnitude filter 
  

  GradientMagnitudeFilterType::Pointer gradient =
GradientMagnitudeFilterType::New();
  //gradient->SetUsePrincipleComponents( ?????? ));

 
  
  // Finally we set up the watershed filter.
  

  WatershedFilterType::Pointer watershed =
WatershedFilterType::New();
  watershed->SetLevel( 1.0 );
  watershed->SetThreshold( 0.5 );


  //  Connect a simple, linear pipeline. 
 

  regionfilter->SetInput( reader->GetOutput() );
  diffusion->SetInput(regionfilter->GetOutput());
  gradient->SetInput(diffusion->GetOutput());
  watershed->SetInput(gradient->GetOutput());
  caster->SetInput( (InternalImageType*)
watershed->GetOutput() );

 
  
// Go  from ITK to VTK


   typedef itk::ImageToVTKImageFilter<OutputImageType>
ConnectorType;   
   
   ConnectorType::Pointer connector=
ConnectorType::New();

   connector->SetInput(caster ->GetOutput() );


    // Create the Image Mapper

    vtkImageMapper *mapper = vtkImageMapper::New();
         mapper -> SetInput(connector -> GetOutput());
         mapper -> SetColorWindow(255);
         mapper -> SetColorLevel(128);
        
     // Create the Actor

    vtkActor2D *actor = vtkActor2D::New();
         actor -> SetMapper(mapper);


     // Create the Rendering Window for viewing what
you've done

    vtkRenderer *imager = vtkRenderer::New();
           imager -> AddActor2D(actor);
        

  
    vtkRenderWindow *imgWin = vtkRenderWindow::New();
           imgWin -> AddRenderer(imager);
           
            

    
    vtkRenderWindowInteractor *iren =
vtkRenderWindowInteractor::New();
           iren -> SetRenderWindow(imgWin);
           
           imager->SetBackground(1,1,1);
           imgWin->SetSize(250,250);


    imgWin -> Render();
    iren->Start();

    
  // Clean up
          
         mapper -> Delete();
	     actor -> Delete();
		 imager -> Delete();
		 imgWin -> Delete();
         iren -> Delete();
 




  return 0;
}
 

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