itkMutualInformationImageToImageMetric.h

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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkMutualInformationImageToImageMetric.h,v $
  Language:  C++
  Date:      $Date: 2009-04-23 03:53:36 $
  Version:   $Revision: 1.45 $

  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 __itkMutualInformationImageToImageMetric_h
#define __itkMutualInformationImageToImageMetric_h

#include "itkImageToImageMetric.h"
#include "itkCovariantVector.h"
#include "itkPoint.h"

#include "itkIndex.h"
#include "itkKernelFunction.h"
#include "itkCentralDifferenceImageFunction.h"

namespace itk
{

template <class TFixedImage,class TMovingImage >
class ITK_EXPORT MutualInformationImageToImageMetric :
    public ImageToImageMetric< TFixedImage, TMovingImage >
{
public:

  typedef MutualInformationImageToImageMetric             Self;
  typedef ImageToImageMetric< TFixedImage, TMovingImage > Superclass;
  typedef SmartPointer<Self>                              Pointer;
  typedef SmartPointer<const Self>                        ConstPointer;

  itkNewMacro(Self);

  itkTypeMacro(MutualInformationImageToImageMetric, ImageToImageMetric);

  typedef typename Superclass::TransformType            TransformType;
  typedef typename Superclass::TransformPointer         TransformPointer;
  typedef typename Superclass::TransformJacobianType    TransformJacobianType;
  typedef typename Superclass::InterpolatorType         InterpolatorType;
  typedef typename Superclass::MeasureType              MeasureType;
  typedef typename Superclass::DerivativeType           DerivativeType;
  typedef typename Superclass::ParametersType           ParametersType;
  typedef typename Superclass::FixedImageType           FixedImageType;
  typedef typename Superclass::MovingImageType          MovingImageType;
  typedef typename Superclass::FixedImageConstPointer   FixedImageConstPointer;
  typedef typename Superclass::MovingImageConstPointer  MovingImageCosntPointer;

  typedef typename FixedImageType::IndexType            FixedImageIndexType;
  typedef typename FixedImageIndexType::IndexValueType  FixedImageIndexValueType;
  typedef typename MovingImageType::IndexType           MovingImageIndexType;
  typedef typename TransformType::InputPointType        FixedImagePointType;
  typedef typename TransformType::OutputPointType       MovingImagePointType;

  itkStaticConstMacro(MovingImageDimension, unsigned int,
                      MovingImageType::ImageDimension);

  void GetDerivative( 
    const ParametersType& parameters,
    DerivativeType & Derivative ) const;

  MeasureType GetValue( const ParametersType& parameters ) const;

  void GetValueAndDerivative( const ParametersType& parameters, 
                              MeasureType& Value, DerivativeType& Derivative ) const;

  void SetNumberOfSpatialSamples( unsigned int num );

  itkGetConstReferenceMacro( NumberOfSpatialSamples, unsigned int );

  itkSetClampMacro( MovingImageStandardDeviation, double, 
                    NumericTraits<double>::NonpositiveMin(), NumericTraits<double>::max() );
  itkGetConstReferenceMacro( MovingImageStandardDeviation, double );

  itkSetClampMacro( FixedImageStandardDeviation, double,
                    NumericTraits<double>::NonpositiveMin(), NumericTraits<double>::max() );
  itkGetConstMacro( FixedImageStandardDeviation, double );

  itkSetObjectMacro( KernelFunction, KernelFunction );
  itkGetObjectMacro( KernelFunction, KernelFunction );

  void ReinitializeSeed();
  void ReinitializeSeed(int);

protected:
  MutualInformationImageToImageMetric();
  virtual ~MutualInformationImageToImageMetric() {};
  void PrintSelf(std::ostream& os, Indent indent) const;

private:
  MutualInformationImageToImageMetric(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented
  
  class SpatialSample
    {
    public:
    SpatialSample():FixedImageValue(0.0),MovingImageValue(0.0)
      { FixedImagePointValue.Fill( 0.0 ); }
    ~SpatialSample(){};

    FixedImagePointType              FixedImagePointValue;
    double                           FixedImageValue;
    double                           MovingImageValue;
    };

  typedef std::vector<SpatialSample>  SpatialSampleContainer;

  mutable SpatialSampleContainer      m_SampleA;

  mutable SpatialSampleContainer      m_SampleB;

  unsigned int                        m_NumberOfSpatialSamples;
  double                              m_MovingImageStandardDeviation;
  double                              m_FixedImageStandardDeviation;
  typename KernelFunction::Pointer    m_KernelFunction;
  double                              m_MinProbability;

  virtual void SampleFixedImageDomain( SpatialSampleContainer& samples ) const;

  void CalculateDerivatives( const FixedImagePointType& , DerivativeType& ) const;

  typedef typename Superclass::CoordinateRepresentationType  
  CoordinateRepresentationType;
  typedef CentralDifferenceImageFunction< MovingImageType, 
                                          CoordinateRepresentationType > DerivativeFunctionType;

  typename DerivativeFunctionType::Pointer  m_DerivativeCalculator;

  bool             m_ReseedIterator;
  int              m_RandomSeed;
  

};

} // end namespace itk

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

#endif