/*========================================================================= * * 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 itkSymmetricForcesDemonsRegistrationFunction_h #define itkSymmetricForcesDemonsRegistrationFunction_h #include "itkPDEDeformableRegistrationFunction.h" #include "itkPoint.h" #include "itkLinearInterpolateImageFunction.h" #include "itkCentralDifferenceImageFunction.h" namespace itk { /** * \class SymmetricForcesDemonsRegistrationFunction * * This class encapsulate the PDE which drives the demons registration * algorithm (formula (5) in J.-P. Thirions's paper "Fast Non-Rigid Matching of * 3D MEdical Images", May 1995). It is used by SymmetricForcesDemonsRegistrationFilter * to compute the output displacement field which will map a moving image onto a * a fixed image. * * This class was contributed by Corinne Mattmann, ETH Zurich, Switzerland. * based on a variation of the DemonsRegistrationFunction. The basic modification * is to use equation (5) from Thirion's paper along with the modification for * avoiding large displacements when gradients have small values. * * Non-integer moving image values are obtained by using * interpolation. The default interpolator is of type * LinearInterpolateImageFunction. The user may set other * interpolators via method SetMovingImageInterpolator. Note that the input * interpolator must derive from baseclass InterpolateImageFunction. * * This class is templated over the fixed image type, moving image type, * and the displacement field type. * * \warning This filter assumes that the fixed image type, moving image type * and displacement field type all have the same number of dimensions. * * \sa SymmetricForcesDemonsRegistrationFilter * \sa DemonsRegistrationFilter * \sa DemonsRegistrationFunction * \ingroup FiniteDifferenceFunctions * \ingroup ITKPDEDeformableRegistration */ template< typename TFixedImage, typename TMovingImage, typename TDisplacementField > class ITK_TEMPLATE_EXPORT SymmetricForcesDemonsRegistrationFunction: public PDEDeformableRegistrationFunction< TFixedImage, TMovingImage, TDisplacementField > { public: /** Standard class typedefs. */ typedef SymmetricForcesDemonsRegistrationFunction Self; typedef PDEDeformableRegistrationFunction< TFixedImage, TMovingImage, TDisplacementField > Superclass; typedef SmartPointer< Self > Pointer; typedef SmartPointer< const Self > ConstPointer; /** Method for creation through the object factory. */ itkNewMacro(Self); /** Run-time type information (and related methods). */ itkTypeMacro(SymmetricForcesDemonsRegistrationFunction, PDEDeformableRegistrationFunction); /** MovingImage image type. */ typedef typename Superclass::MovingImageType MovingImageType; typedef typename Superclass::MovingImagePointer MovingImagePointer; /** FixedImage image type. */ typedef typename Superclass::FixedImageType FixedImageType; typedef typename Superclass::FixedImagePointer FixedImagePointer; typedef typename FixedImageType::IndexType IndexType; typedef typename FixedImageType::SizeType SizeType; typedef typename FixedImageType::SpacingType SpacingType; /** Deformation field type. */ typedef typename Superclass::DisplacementFieldType DisplacementFieldType; typedef typename Superclass::DisplacementFieldTypePointer DisplacementFieldTypePointer; /** Inherit some enums from the superclass. */ itkStaticConstMacro(ImageDimension, unsigned int, Superclass::ImageDimension); /** Inherit some enums from the superclass. */ typedef typename Superclass::PixelType PixelType; typedef typename Superclass::RadiusType RadiusType; typedef typename Superclass::NeighborhoodType NeighborhoodType; typedef typename Superclass::FloatOffsetType FloatOffsetType; typedef typename Superclass::TimeStepType TimeStepType; /** Interpolator type. */ typedef double CoordRepType; typedef InterpolateImageFunction< MovingImageType, CoordRepType > InterpolatorType; typedef typename InterpolatorType::Pointer InterpolatorPointer; typedef typename InterpolatorType::PointType PointType; typedef LinearInterpolateImageFunction< MovingImageType, CoordRepType > DefaultInterpolatorType; /** Covariant vector type. */ typedef CovariantVector< double, itkGetStaticConstMacro(ImageDimension) > CovariantVectorType; /** Gradient calculator type. */ typedef CentralDifferenceImageFunction< FixedImageType > GradientCalculatorType; typedef typename GradientCalculatorType::Pointer GradientCalculatorPointer; /** Set the moving image interpolator. */ void SetMovingImageInterpolator(InterpolatorType *ptr) { m_MovingImageInterpolator = ptr; } /** Get the moving image interpolator. */ InterpolatorType * GetMovingImageInterpolator(void) { return m_MovingImageInterpolator; } /** This class uses a constant timestep of 1. */ virtual TimeStepType ComputeGlobalTimeStep( void *itkNotUsed(GlobalData) ) const ITK_OVERRIDE { return m_TimeStep; } /** Return a pointer to a global data structure that is passed to * this object from the solver at each calculation. */ virtual void * GetGlobalDataPointer() const ITK_OVERRIDE { GlobalDataStruct *global = new GlobalDataStruct(); global->m_SumOfSquaredDifference = 0.0; global->m_NumberOfPixelsProcessed = 0L; global->m_SumOfSquaredChange = 0; return global; } /** Release memory for global data structure. */ virtual void ReleaseGlobalDataPointer(void *GlobalData) const ITK_OVERRIDE; /** Set the object's state before each iteration. */ virtual void InitializeIteration() ITK_OVERRIDE; /** This method is called by a finite difference solver image filter at * each pixel that does not lie on a data set boundary */ virtual PixelType ComputeUpdate( const NeighborhoodType & neighborhood, void *globalData, const FloatOffsetType & offset = FloatOffsetType(0.0) ) ITK_OVERRIDE; /** Get the metric value. The metric value is the mean square difference * in intensity between the fixed image and transforming moving image * computed over the the overlapping region between the two images. */ virtual double GetMetric() const { return m_Metric; } /** Get the rms change in displacement field. */ virtual const double & GetRMSChange() const { return m_RMSChange; } /** Set/Get the threshold below which the absolute difference of * intensity yields a match. When the intensities match between a * moving and fixed image pixel, the update vector (for that * iteration) will be the zero vector. Default is 0.001. */ virtual void SetIntensityDifferenceThreshold(double); virtual double GetIntensityDifferenceThreshold() const; protected: SymmetricForcesDemonsRegistrationFunction(); ~SymmetricForcesDemonsRegistrationFunction() ITK_OVERRIDE {} void PrintSelf(std::ostream & os, Indent indent) const ITK_OVERRIDE; /** FixedImage image neighborhood iterator type. */ typedef ConstNeighborhoodIterator< FixedImageType > FixedImageNeighborhoodIteratorType; /** A global data type for this class of equation. Used to store * iterators for the fixed image. */ struct GlobalDataStruct { double m_SumOfSquaredDifference; SizeValueType m_NumberOfPixelsProcessed; double m_SumOfSquaredChange; }; private: ITK_DISALLOW_COPY_AND_ASSIGN(SymmetricForcesDemonsRegistrationFunction); /** Cache fixed image information. */ SpacingType m_FixedImageSpacing; PointType m_FixedImageOrigin; double m_Normalizer; /** Function to compute derivatives of the fixed image. */ GradientCalculatorPointer m_FixedImageGradientCalculator; /** Function to interpolate the moving image. */ InterpolatorPointer m_MovingImageInterpolator; /** The global timestep. */ TimeStepType m_TimeStep; /** Threshold below which the denominator term is considered zero. */ double m_DenominatorThreshold; /** Threshold below which two intensity value are assumed to match. */ double m_IntensityDifferenceThreshold; /** The metric value is the mean square difference in intensity between * the fixed image and transforming moving image computed over the * the overlapping region between the two images. */ mutable double m_Metric; mutable double m_SumOfSquaredDifference; mutable SizeValueType m_NumberOfPixelsProcessed; mutable double m_RMSChange; mutable double m_SumOfSquaredChange; /** Mutex lock to protect modification to metric. */ mutable SimpleFastMutexLock m_MetricCalculationLock; }; } // end namespace itk #ifndef ITK_MANUAL_INSTANTIATION #include "itkSymmetricForcesDemonsRegistrationFunction.hxx" #endif #endif