itkGradientVectorFlowImageFilter.h

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/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkGradientVectorFlowImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2009-04-23 03:53:35 $
  Version:   $Revision: 1.15 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __itkGradientVectorFlowImageFilter_h
#define __itkGradientVectorFlowImageFilter_h

#include "itkImageToImageFilter.h"
#include "vnl/vnl_matrix_fixed.h"
#include "vnl/vnl_math.h"
#include "itkImage.h"
#include "itkVector.h"
#include "itkLaplacianImageFilter.h"
#include "itkImageRegionIterator.h"
#include "itkImageRegionConstIteratorWithIndex.h"

namespace itk
{

template <class TInputImage, class TOutputImage, class TInternalPixel=double>
class ITK_EXPORT GradientVectorFlowImageFilter : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  typedef GradientVectorFlowImageFilter  Self;

  typedef ImageToImageFilter<TInputImage, TOutputImage> Superclass;

  typedef SmartPointer<Self>        Pointer;
  typedef SmartPointer<const Self>  ConstPointer;

  itkNewMacro(Self);

  itkTypeMacro(GradientVectorFlowImageFilter, ImageToImageFilter);

  typedef TInputImage  InputImageType;
  typedef TOutputImage OutputImageType;

  typedef typename TInputImage::IndexType      IndexType;
  typedef typename TInputImage::SizeType       SizeType;
  typedef typename TInputImage::PixelType      PixelType;
  typedef typename OutputImageType::Pointer    OutputImagePointer;
  typedef typename OutputImageType::RegionType RegionType;

//  typedef ImageRegionConstIterator<InputImageType> InputImageConstIterator;
  typedef ImageRegionIterator<InputImageType>                InputImageIterator;
  typedef ImageRegionConstIteratorWithIndex<InputImageType>  InputImageConstIterator;
  typedef ImageRegionIterator<OutputImageType>               OutputImageIterator;

  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage::ImageDimension);
  itkStaticConstMacro(OutputImageDimension, unsigned int,
                      TOutputImage::ImageDimension);

  typedef TInternalPixel                         InternalPixelType;
  typedef itk::Image<InternalPixelType, itkGetStaticConstMacro(ImageDimension)>
                                                 InternalImageType;
  typedef typename InternalImageType::Pointer    InternalImagePointer;
  typedef ImageRegionIterator<InternalImageType> InternalImageIterator;

  typedef LaplacianImageFilter<InternalImageType, InternalImageType>
                                                 LaplacianFilterType;
  typedef typename LaplacianFilterType::Pointer  LaplacianFilterPointer;

  itkSetMacro(LaplacianFilter, LaplacianFilterPointer);

  itkSetMacro(TimeStep, double);
  itkGetConstMacro(TimeStep, double);

  itkSetMacro(NoiseLevel, double);
  itkGetConstMacro(NoiseLevel, double);

  itkSetMacro(IterationNum, int);
  itkGetConstMacro(IterationNum, int);

#ifdef ITK_USE_CONCEPT_CHECKING

  itkConceptMacro(SameDimensionCheck,
    (Concept::SameDimension<ImageDimension, OutputImageDimension>));
  itkConceptMacro(InputHasNumericTraitsCheck,
    (Concept::HasNumericTraits<typename PixelType::ValueType>));
  itkConceptMacro(OutputHasNumericTraitsCheck,
    (Concept::HasNumericTraits<typename TOutputImage::PixelType::ValueType>));

#endif

protected:
  GradientVectorFlowImageFilter();
  ~GradientVectorFlowImageFilter() {}
  GradientVectorFlowImageFilter(const Self&) {}
  void operator=(const Self&) {}
  void PrintSelf(std::ostream& os, Indent indent) const; 

  virtual void GenerateData();

  void InitInterImage();
  void UpdateInterImage();
  void UpdatePixels();

private:
  // parameters;
  double m_TimeStep; //the timestep of each iteration
  double m_Steps[Superclass::InputImageDimension]; // set to be 1 in all directions in most cases
  double m_NoiseLevel; // the noise level of the image
  int    m_IterationNum;  // the iteration number

  LaplacianFilterPointer                 m_LaplacianFilter;
  typename Superclass::InputImagePointer m_IntermediateImage;

  InternalImagePointer m_InternalImages[Superclass::InputImageDimension];
  InternalImagePointer m_BImage;  // store the "b" value for every pixel

  typename Superclass::InputImagePointer m_CImage; // store the $c_i$ value for every pixel
};

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkGradientVectorFlowImageFilter.txx"
#endif

#endif