itkDemonsRegistrationFunction.h

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/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://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 itkDemonsRegistrationFunction_h
#define itkDemonsRegistrationFunction_h
 
#include "itkPDEDeformableRegistrationFunction.h"
#include "itkPoint.h"
#include "itkLinearInterpolateImageFunction.h"
#include "itkCentralDifferenceImageFunction.h"
#include <mutex>
 
namespace itk
{
template <typename TFixedImage, typename TMovingImage, typename TDisplacementField>
class ITK_TEMPLATE_EXPORT DemonsRegistrationFunction
  : public PDEDeformableRegistrationFunction<TFixedImage, TMovingImage, TDisplacementField>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(DemonsRegistrationFunction);

  using Self = DemonsRegistrationFunction;
  using Superclass = PDEDeformableRegistrationFunction<TFixedImage, TMovingImage, TDisplacementField>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(DemonsRegistrationFunction);

  using typename Superclass::MovingImageType;
  using typename Superclass::MovingImagePointer;

  using typename Superclass::FixedImageType;
  using typename Superclass::FixedImagePointer;
  using IndexType = typename FixedImageType::IndexType;
  using SizeType = typename FixedImageType::SizeType;
  using SpacingType = typename FixedImageType::SpacingType;

  using typename Superclass::DisplacementFieldType;
  using typename Superclass::DisplacementFieldTypePointer;

  static constexpr unsigned int ImageDimension = Superclass::ImageDimension;

  using typename Superclass::PixelType;
  using typename Superclass::RadiusType;
  using typename Superclass::NeighborhoodType;
  using typename Superclass::FloatOffsetType;
  using typename Superclass::TimeStepType;

  using CoordinateType = double;
#ifndef ITK_FUTURE_LEGACY_REMOVE
  using CoordRepType ITK_FUTURE_DEPRECATED(
    "ITK 6 discourages using `CoordRepType`. Please use `CoordinateType` instead!") = CoordinateType;
#endif
  using InterpolatorType = InterpolateImageFunction<MovingImageType, CoordinateType>;
  using InterpolatorPointer = typename InterpolatorType::Pointer;
  using PointType = typename InterpolatorType::PointType;
  using DefaultInterpolatorType = LinearInterpolateImageFunction<MovingImageType, CoordinateType>;

  using CovariantVectorType = CovariantVector<double, Self::ImageDimension>;

  using GradientCalculatorType = CentralDifferenceImageFunction<FixedImageType>;
  using GradientCalculatorPointer = typename GradientCalculatorType::Pointer;

  using MovingImageGradientCalculatorType = CentralDifferenceImageFunction<MovingImageType, CoordinateType>;
  using MovingImageGradientCalculatorPointer = typename MovingImageGradientCalculatorType::Pointer;

  void
  SetMovingImageInterpolator(InterpolatorType * ptr)
  {
    m_MovingImageInterpolator = ptr;
  }

  InterpolatorType *
  GetMovingImageInterpolator()
  {
    return m_MovingImageInterpolator;
  }

  TimeStepType
  ComputeGlobalTimeStep(void * itkNotUsed(GlobalData)) const override
  {
    return m_TimeStep;
  }

  void *
  GetGlobalDataPointer() const override
  {
    auto * global = new GlobalDataStruct();
 
    global->m_SumOfSquaredDifference = 0.0;
    global->m_NumberOfPixelsProcessed = 0L;
    global->m_SumOfSquaredChange = 0;
    return global;
  }

  void
  ReleaseGlobalDataPointer(void * gd) const override;

  void
  InitializeIteration() override;

  PixelType
  ComputeUpdate(const NeighborhoodType & it, void * gd, const FloatOffsetType & offset = FloatOffsetType(0.0)) override;

  virtual double
  GetMetric() const
  {
    return m_Metric;
  }

  virtual double
  GetRMSChange() const
  {
    return m_RMSChange;
  }

  virtual void
  SetUseMovingImageGradient(bool flag)
  {
    m_UseMovingImageGradient = flag;
  }
  virtual bool
  GetUseMovingImageGradient() const
  {
    return m_UseMovingImageGradient;
  }


  virtual void
  SetIntensityDifferenceThreshold(double);
 
  virtual double
  GetIntensityDifferenceThreshold() const;
 
protected:
  DemonsRegistrationFunction();
  ~DemonsRegistrationFunction() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  using FixedImageNeighborhoodIteratorType = ConstNeighborhoodIterator<FixedImageType>;

  struct GlobalDataStruct
  {
    double        m_SumOfSquaredDifference;
    SizeValueType m_NumberOfPixelsProcessed;
    double        m_SumOfSquaredChange;
  };
 
private:
  // SpacingType                  m_FixedImageSpacing;
  // PointType                    m_FixedImageOrigin;
  PixelType m_ZeroUpdateReturn{};
  double    m_Normalizer{};

  GradientCalculatorPointer m_FixedImageGradientCalculator{};

  MovingImageGradientCalculatorPointer m_MovingImageGradientCalculator{};
  bool                                 m_UseMovingImageGradient{};

  InterpolatorPointer m_MovingImageInterpolator{};

  TimeStepType m_TimeStep{};

  double m_DenominatorThreshold{};

  double m_IntensityDifferenceThreshold{};

  mutable double        m_Metric{};
  mutable double        m_SumOfSquaredDifference{};
  mutable SizeValueType m_NumberOfPixelsProcessed{};
  mutable double        m_RMSChange{};
  mutable double        m_SumOfSquaredChange{};

  mutable std::mutex m_MetricCalculationMutex{};
};
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkDemonsRegistrationFunction.hxx"
#endif
 
#endif