itkMutualInformationImageToImageMetric.h

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/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef itkMutualInformationImageToImageMetric_h
#define itkMutualInformationImageToImageMetric_h

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

#include "itkIndex.h"
#include "itkKernelFunctionBase.h"

namespace itk
{
template< typename TFixedImage, typename TMovingImage >
class ITK_TEMPLATE_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;

  typedef KernelFunctionBase<double>                       KernelFunctionType;

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

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

  MeasureType GetValue(const ParametersType & parameters) const ITK_OVERRIDE;

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

  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, KernelFunctionType);
  itkGetModifiableObjectMacro(KernelFunction, KernelFunctionType);


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

private:
  ITK_DISALLOW_COPY_AND_ASSIGN(MutualInformationImageToImageMetric);

  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;
  double       m_MinProbability;

  typename KernelFunctionType::Pointer m_KernelFunction;

  virtual void SampleFixedImageDomain(SpatialSampleContainer & samples) const;

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

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

  typename DerivativeFunctionType::Pointer m_DerivativeCalculator;

};
} // end namespace itk

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

#endif