#include <itkMutualInformationImageToImageMetric.h>

Inheritance diagram for itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >:

Collaboration diagram for itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >:

Detailed Description

template<typename TFixedImage, typename TMovingImage>
class itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >

Computes the mutual information between two images to be registered.

MutualInformationImageToImageMetric computes the mutual information between a fixed and moving image to be registered.

This class is templated over the FixedImage type and the MovingImage type.

The fixed and moving images are set via methods SetFixedImage() and SetMovingImage(). This metric makes use of user specified Transform and Interpolator. The Transform is used to map points from the fixed image to the moving image domain. The Interpolator is used to evaluate the image intensity at user specified geometric points in the moving image. The Transform and Interpolator are set via methods SetTransform() and SetInterpolator().

Warning: This metric assumes that the moving image has already been connected to the interpolator outside of this class.

The method GetValue() computes of the mutual information while method GetValueAndDerivative() computes both the mutual information and its derivatives with respect to the transform parameters.

The calculations are based on the method of Viola and Wells where the probability density distributions are estimated using Parzen windows.

By default a Gaussian kernel is used in the density estimation. Other option include Cauchy and spline-based. A user can specify the kernel passing in a pointer a KernelFunctionBase using the SetKernelFunction() method.

Mutual information is estimated using two sample sets: one to calculate the singular and joint pdf's and one to calculate the entropy integral. By default 50 samples points are used in each set. Other values can be set via the SetNumberOfSpatialSamples() method.

Quality of the density estimate depends on the choice of the kernel's standard deviation. Optimal choice will depend on the images. It is can be shown that around the optimal variance, the mutual information estimate is relatively insensitive to small changes of the standard deviation. In our experiments, we have found that a standard deviation of 0.4 works well for images normalized to have a mean of zero and standard deviation of 1.0. The variance can be set via methods SetFixedImageStandardDeviation() and SetMovingImageStandardDeviation().

Implementaton of this class is based on: Viola, P. and Wells III, W. (1997). "Alignment by Maximization of Mutual Information" International Journal of Computer Vision, 24(2):137-154

See Also: KernelFunctionBase; GaussianKernelFunction

Wiki Examples:

Examples:: Examples/RegistrationITKv3/ImageRegistration2.cxx, Examples/RegistrationITKv4/ImageRegistration2.cxx, SphinxExamples/src/Registration/Common/PerformMultiModalityRegistrationWithMutualInformation/Code.cxx, WikiExamples/Registration/MutualInformation.cxx, and WikiExamples/Registration/MutualInformationAffine.cxx.

Definition at line 94 of file itkMutualInformationImageToImageMetric.h.

Classes
class	SpatialSample

Public Types
typedef SmartPointer< const Self >	ConstPointer

typedef Superclass::DerivativeType	DerivativeType

typedef Superclass::FixedImageConstPointer	FixedImageConstPointer

typedef FixedImageType::IndexType	FixedImageIndexType

typedef FixedImageIndexType::IndexValueType	FixedImageIndexValueType

typedef TransformType::InputPointType	FixedImagePointType

typedef Superclass::FixedImageType	FixedImageType

typedef Superclass::InterpolatorType	InterpolatorType

typedef KernelFunctionBase < double >	KernelFunctionType

typedef Superclass::MeasureType	MeasureType

typedef Superclass::MovingImageConstPointer	MovingImageCosntPointer

typedef MovingImageType::IndexType	MovingImageIndexType

typedef TransformType::OutputPointType	MovingImagePointType

typedef Superclass::MovingImageType	MovingImageType

typedef Superclass::ParametersType	ParametersType

typedef SmartPointer< Self >	Pointer

typedef MutualInformationImageToImageMetric	Self

typedef ImageToImageMetric < TFixedImage, TMovingImage >	Superclass

typedef Superclass::TransformJacobianType	TransformJacobianType

typedef Superclass::TransformPointer	TransformPointer

typedef Superclass::TransformType	TransformType

Public Types inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
typedef SmartPointer< const Self >	ConstPointer

typedef Superclass::ParametersValueType	CoordinateRepresentationType

typedef Superclass::DerivativeType	DerivativeType

typedef FixedImageType::ConstPointer	FixedImageConstPointer

typedef std::vector < FixedImageIndexType >	FixedImageIndexContainer

typedef FixedImageType::IndexType	FixedImageIndexType

typedef FixedImageIndexType::IndexValueType	FixedImageIndexValueType

typedef FixedImageMaskType::ConstPointer	FixedImageMaskConstPointer

typedef FixedImageMaskType::Pointer	FixedImageMaskPointer

typedef SpatialObject < itkGetStaticConstMacro(FixedImageDimension) >	FixedImageMaskType

typedef TFixedImage::PixelType	FixedImagePixelType

typedef TransformType::InputPointType	FixedImagePointType

typedef FixedImageType::RegionType	FixedImageRegionType

typedef TFixedImage	FixedImageType

typedef TransformType::InputPointType	InputPointType

typedef InterpolatorType::Pointer	InterpolatorPointer

typedef InterpolateImageFunction < MovingImageType, CoordinateRepresentationType >	InterpolatorType

typedef Superclass::MeasureType	MeasureType

typedef MovingImageType::ConstPointer	MovingImageConstPointer

typedef MovingImageType::IndexType	MovingImageIndexType

typedef MovingImageMaskType::ConstPointer	MovingImageMaskConstPointer

typedef MovingImageMaskType::Pointer	MovingImageMaskPointer

typedef SpatialObject < itkGetStaticConstMacro(MovingImageDimension) >	MovingImageMaskType

typedef TMovingImage::PixelType	MovingImagePixelType

typedef TransformType::OutputPointType	MovingImagePointType

typedef TMovingImage	MovingImageType

typedef MultiThreader	MultiThreaderType

typedef TransformType::OutputPointType	OutputPointType

typedef Superclass::ParametersType	ParametersType

typedef SmartPointer< Self >	Pointer

typedef ImageToImageMetric	Self

typedef SingleValuedCostFunction	Superclass

typedef TransformType::JacobianType	TransformJacobianType

typedef TransformType::ParametersType	TransformParametersType

typedef TransformType::Pointer	TransformPointer

typedef Transform < CoordinateRepresentationType, itkGetStaticConstMacro(MovingImageDimension), itkGetStaticConstMacro(FixedImageDimension) >	TransformType

typedef NumericTraits < MovingImagePixelType > ::RealType	RealType

typedef CovariantVector < RealType, itkGetStaticConstMacro(MovingImageDimension) >	GradientPixelType

typedef Image < GradientPixelType, itkGetStaticConstMacro(MovingImageDimension) >	GradientImageType

typedef SmartPointer < GradientImageType >	GradientImagePointer

typedef GradientRecursiveGaussianImageFilter < MovingImageType, GradientImageType >	GradientImageFilterType

typedef GradientImageFilterType::Pointer	GradientImageFilterPointer

Public Types inherited from itk::SingleValuedCostFunction
typedef SmartPointer< const Self >	ConstPointer

typedef Array < ParametersValueType >	DerivativeType

typedef double	MeasureType

typedef Superclass::ParametersType	ParametersType

typedef Superclass::ParametersValueType	ParametersValueType

typedef SmartPointer< Self >	Pointer

typedef SingleValuedCostFunction	Self

typedef CostFunction	Superclass

Public Types inherited from itk::CostFunctionTemplate< TInternalComputationValueType >
typedef SmartPointer< const Self >	ConstPointer

typedef OptimizerParameters < TInternalComputationValueType >	ParametersType

typedef TInternalComputationValueType	ParametersValueType

typedef SmartPointer< Self >	Pointer

typedef CostFunctionTemplate	Self

typedef Object	Superclass

Public Types inherited from itk::Object
typedef SmartPointer< const Self >	ConstPointer

typedef SmartPointer< Self >	Pointer

typedef Object	Self

typedef LightObject	Superclass

Public Types inherited from itk::LightObject
typedef SmartPointer< const Self >	ConstPointer

typedef SmartPointer< Self >	Pointer

typedef LightObject	Self

Public Member Functions
virtual ::itk::LightObject::Pointer	CreateAnother () const

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

virtual const char *	GetNameOfClass () const

virtual const unsigned int &	GetNumberOfSpatialSamples () const

MeasureType	GetValue (const ParametersType &parameters) const override

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

void	SetNumberOfSpatialSamples (unsigned int num)


virtual void	SetMovingImageStandardDeviation (double _arg)

virtual const double &	GetMovingImageStandardDeviation () const


virtual void	SetFixedImageStandardDeviation (double _arg)

virtual double	GetFixedImageStandardDeviation () const


virtual void	SetKernelFunction (KernelFunctionType *_arg)

virtual KernelFunctionType *	GetModifiableKernelFunction ()

virtual const KernelFunctionType *	GetKernelFunction () const

Public Member Functions inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
virtual void	ComputeGradient ()

virtual const FixedImageRegionType &	GetFixedImageRegion () const

virtual const FixedImagePixelType &	GetFixedImageSamplesIntensityThreshold () const

virtual const GradientImageType *	GetGradientImage () const

virtual const InterpolatorType *	GetInterpolator () const

virtual GradientImageType *	GetModifiableGradientImage ()

virtual InterpolatorType *	GetModifiableInterpolator ()

virtual TransformType *	GetModifiableTransform ()

SizeValueType	GetNumberOfMovingImageSamples (void)

virtual unsigned int	GetNumberOfParameters (void) const override

virtual const SizeValueType &	GetNumberOfPixelsCounted () const

SizeValueType	GetNumberOfSpatialSamples (void)

virtual const TransformType *	GetTransform () const

virtual const bool &	GetUseAllPixels () const

virtual const bool &	GetUseFixedImageIndexes () const

virtual const bool &	GetUseFixedImageSamplesIntensityThreshold () const

virtual const bool &	GetUseSequentialSampling () const

virtual void	Initialize (void)

virtual void	MultiThreadingInitialize (void)

void	SetFixedImageIndexes (const FixedImageIndexContainer &indexes)

virtual void	SetFixedImageRegion (const FixedImageRegionType reg)

void	SetFixedImageSamplesIntensityThreshold (const FixedImagePixelType &thresh)

virtual void	SetInterpolator (InterpolatorType *_arg)

void	SetNumberOfSpatialSamples (SizeValueType num)

virtual void	SetTransform (TransformType *_arg)

void	SetTransformParameters (const ParametersType &parameters) const

void	SetUseAllPixels (bool useAllPixels)

void	SetUseFixedImageIndexes (bool useIndex)

void	SetUseFixedImageSamplesIntensityThreshold (bool useThresh)

void	SetUseSequentialSampling (bool sequentialSampling)

void	UseAllPixelsOff (void)

void	UseAllPixelsOn (void)

virtual void	SetFixedImage (const FixedImageType *_arg)

virtual const FixedImageType *	GetFixedImage () const

virtual void	SetMovingImage (const MovingImageType *_arg)

virtual const MovingImageType *	GetMovingImage () const

virtual void	SetMovingImageMask (MovingImageMaskType *_arg)

virtual void	SetMovingImageMask (const MovingImageMaskType *_arg)

virtual const MovingImageMaskType *	GetMovingImageMask () const

virtual void	SetFixedImageMask (FixedImageMaskType *_arg)

virtual void	SetFixedImageMask (const FixedImageMaskType *_arg)

virtual const FixedImageMaskType *	GetFixedImageMask () const

void	SetNumberOfThreads (ThreadIdType numberOfThreads)

virtual const ThreadIdType &	GetNumberOfThreads () const

virtual void	SetComputeGradient (bool _arg)

virtual const bool &	GetComputeGradient () const

virtual void	ComputeGradientOn ()

virtual void	ComputeGradientOff ()

virtual void	SetNumberOfFixedImageSamples (SizeValueType numSamples)

virtual const SizeValueType &	GetNumberOfFixedImageSamples () const

void	ReinitializeSeed ()

void	ReinitializeSeed (int seed)

virtual void	SetUseCachingOfBSplineWeights (bool _arg)

virtual const bool &	GetUseCachingOfBSplineWeights () const

virtual void	UseCachingOfBSplineWeightsOn ()

virtual void	UseCachingOfBSplineWeightsOff ()

virtual MultiThreaderType *	GetModifiableThreader ()

virtual const MultiThreaderType *	GetThreader () const

const TransformPointer *	GetThreaderTransform ()

Public Member Functions inherited from itk::Object
unsigned long	AddObserver (const EventObject &event, Command *)

unsigned long	AddObserver (const EventObject &event, Command *) const

virtual void	DebugOff () const

virtual void	DebugOn () const

Command *	GetCommand (unsigned long tag)

bool	GetDebug () const

MetaDataDictionary &	GetMetaDataDictionary ()

const MetaDataDictionary &	GetMetaDataDictionary () const

virtual ModifiedTimeType	GetMTime () const

virtual const TimeStamp &	GetTimeStamp () const

bool	HasObserver (const EventObject &event) const

void	InvokeEvent (const EventObject &)

void	InvokeEvent (const EventObject &) const

virtual void	Modified () const

virtual void	Register () const override

void	RemoveAllObservers ()

void	RemoveObserver (unsigned long tag)

void	SetDebug (bool debugFlag) const

void	SetMetaDataDictionary (const MetaDataDictionary &rhs)

virtual void	SetReferenceCount (int) override

virtual void	UnRegister () const noexceptoverride

virtual void	SetObjectName (std::string _arg)

virtual const std::string &	GetObjectName () const

Public Member Functions inherited from itk::LightObject
virtual void	Delete ()

virtual int	GetReferenceCount () const

	itkCloneMacro (Self)

void	Print (std::ostream &os, Indent indent=0) const

Static Public Member Functions
static Pointer	New ()

Static Public Member Functions inherited from itk::Object
static bool	GetGlobalWarningDisplay ()

static void	GlobalWarningDisplayOff ()

static void	GlobalWarningDisplayOn ()

static Pointer	New ()

static void	SetGlobalWarningDisplay (bool flag)

Static Public Member Functions inherited from itk::LightObject
static void	BreakOnError ()

static Pointer	New ()

Static Public Attributes
static const unsigned int	MovingImageDimension = MovingImageType::ImageDimension

Static Public Attributes inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
static const unsigned int	MovingImageDimension = TMovingImage::ImageDimension

static const unsigned int	FixedImageDimension = TFixedImage::ImageDimension

Protected Member Functions
	MutualInformationImageToImageMetric ()

void	PrintSelf (std::ostream &os, Indent indent) const override

virtual	~MutualInformationImageToImageMetric () override

Protected Member Functions inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
virtual void	ComputeImageDerivatives (const MovingImagePointType &mappedPoint, ImageDerivativesType &gradient, ThreadIdType threadId) const

void	GetValueAndDerivativeMultiThreadedInitiate () const

void	GetValueAndDerivativeMultiThreadedPostProcessInitiate () const

void	GetValueAndDerivativeMultiThreadedPreProcessInitiate () const

virtual void	GetValueAndDerivativeThread (ThreadIdType threadId) const

virtual void	GetValueAndDerivativeThreadPostProcess (ThreadIdType, bool) const

virtual void	GetValueAndDerivativeThreadPreProcess (ThreadIdType, bool) const

virtual bool	GetValueAndDerivativeThreadProcessSample (ThreadIdType, SizeValueType, const MovingImagePointType &, double, const ImageDerivativesType &) const

void	GetValueMultiThreadedInitiate () const

void	GetValueMultiThreadedPostProcessInitiate () const

void	GetValueMultiThreadedPreProcessInitiate () const

virtual void	GetValueThread (ThreadIdType threadId) const

virtual void	GetValueThreadPostProcess (ThreadIdType, bool) const

virtual void	GetValueThreadPreProcess (ThreadIdType, bool) const

virtual bool	GetValueThreadProcessSample (ThreadIdType, SizeValueType, const MovingImagePointType &, double) const

	ImageToImageMetric ()

virtual void	PreComputeTransformValues ()

virtual void	SampleFixedImageIndexes (FixedImageSampleContainer &samples) const

virtual void	SampleFixedImageRegion (FixedImageSampleContainer &samples) const

virtual void	SampleFullFixedImageRegion (FixedImageSampleContainer &samples) const

virtual void	SynchronizeTransforms () const

virtual void	TransformPoint (unsigned int sampleNumber, MovingImagePointType &mappedPoint, bool &sampleWithinSupportRegion, double &movingImageValue, ThreadIdType threadId) const

virtual void	TransformPointWithDerivatives (unsigned int sampleNumber, MovingImagePointType &mappedPoint, bool &sampleWithinSupportRegion, double &movingImageValue, ImageDerivativesType &gradient, ThreadIdType threadId) const

virtual	~ImageToImageMetric () override

Protected Member Functions inherited from itk::SingleValuedCostFunction
	SingleValuedCostFunction ()

virtual	~SingleValuedCostFunction () override

Protected Member Functions inherited from itk::CostFunctionTemplate< TInternalComputationValueType >
	CostFunctionTemplate ()

virtual	~CostFunctionTemplate () override

Protected Member Functions inherited from itk::Object
	Object ()

bool	PrintObservers (std::ostream &os, Indent indent) const

virtual void	SetTimeStamp (const TimeStamp &time)

virtual	~Object () override

Protected Member Functions inherited from itk::LightObject
virtual LightObject::Pointer	InternalClone () const

	LightObject ()

virtual void	PrintHeader (std::ostream &os, Indent indent) const

virtual void	PrintTrailer (std::ostream &os, Indent indent) const

virtual	~LightObject ()

Private Types
typedef Superclass::CoordinateRepresentationType	CoordinateRepresentationType

typedef CentralDifferenceImageFunction < MovingImageType, CoordinateRepresentationType >	DerivativeFunctionType

typedef std::vector < SpatialSample >	SpatialSampleContainer

Private Member Functions
void	CalculateDerivatives (const FixedImagePointType &, DerivativeType &, TransformJacobianType &) const

virtual void	SampleFixedImageDomain (SpatialSampleContainer &samples) const

Private Attributes
DerivativeFunctionType::Pointer	m_DerivativeCalculator

double	m_FixedImageStandardDeviation

KernelFunctionType::Pointer	m_KernelFunction

double	m_MinProbability

double	m_MovingImageStandardDeviation

unsigned int	m_NumberOfSpatialSamples

SpatialSampleContainer	m_SampleA

SpatialSampleContainer	m_SampleB

Additional Inherited Members
Protected Types inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
typedef std::vector< bool >	BooleanArrayType

typedef BSplineInterpolateImageFunction < MovingImageType, CoordinateRepresentationType >	BSplineInterpolatorType

typedef FixedArray < SizeValueType, FixedImageType::ImageDimension >	BSplineParametersOffsetType

typedef BSplineTransformType::ParameterIndexArrayType	BSplineTransformIndexArrayType

typedef Array2D< IndexValueType >	BSplineTransformIndicesArrayType

typedef BSplineBaseTransform < CoordinateRepresentationType, FixedImageType::ImageDimension, itkGetStaticConstMacro(DeformationSplineOrder) >	BSplineTransformType

typedef Array2D< WeightsValueType >	BSplineTransformWeightsArrayType

typedef BSplineTransformType::WeightsType	BSplineTransformWeightsType

typedef CentralDifferenceImageFunction < MovingImageType, CoordinateRepresentationType >	DerivativeFunctionType

typedef std::vector < FixedImageSamplePoint >	FixedImageSampleContainer

typedef CovariantVector < double, itkGetStaticConstMacro(MovingImageDimension) >	ImageDerivativesType

typedef BSplineTransformIndexArrayType::ValueType	IndexValueType

typedef std::vector < MovingImagePointType >	MovingImagePointArrayType

typedef BSplineTransformWeightsType::ValueType	WeightsValueType

Static Protected Member Functions inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
static ITK_THREAD_RETURN_TYPE	GetValueAndDerivativeMultiThreaded (void *arg)

static ITK_THREAD_RETURN_TYPE	GetValueAndDerivativeMultiThreadedPostProcess (void *arg)

static ITK_THREAD_RETURN_TYPE	GetValueAndDerivativeMultiThreadedPreProcess (void *arg)

static ITK_THREAD_RETURN_TYPE	GetValueMultiThreaded (void *arg)

static ITK_THREAD_RETURN_TYPE	GetValueMultiThreadedPostProcess (void *arg)

static ITK_THREAD_RETURN_TYPE	GetValueMultiThreadedPreProcess (void *arg)

Protected Attributes inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
BSplineInterpolatorType::Pointer	m_BSplineInterpolator

BSplineParametersOffsetType	m_BSplineParametersOffset

MovingImagePointArrayType	m_BSplinePreTransformPointsArray

BSplineTransformType::Pointer	m_BSplineTransform

BSplineTransformIndexArrayType	m_BSplineTransformIndices

BSplineTransformIndicesArrayType	m_BSplineTransformIndicesArray

BSplineTransformWeightsType	m_BSplineTransformWeights

BSplineTransformWeightsArrayType	m_BSplineTransformWeightsArray

bool	m_ComputeGradient

DerivativeFunctionType::Pointer	m_DerivativeCalculator

FixedImageConstPointer	m_FixedImage

FixedImageIndexContainer	m_FixedImageIndexes

FixedImageMaskConstPointer	m_FixedImageMask

FixedImageSampleContainer	m_FixedImageSamples

FixedImagePixelType	m_FixedImageSamplesIntensityThreshold

GradientImagePointer	m_GradientImage

InterpolatorPointer	m_Interpolator

bool	m_InterpolatorIsBSpline

MovingImageConstPointer	m_MovingImage

MovingImageMaskConstPointer	m_MovingImageMask

SizeValueType	m_NumberOfFixedImageSamples

SizeValueType	m_NumberOfParameters

SizeValueType	m_NumberOfPixelsCounted

ThreadIdType	m_NumberOfThreads

SizeValueType	m_NumBSplineWeights

int	m_RandomSeed

bool	m_ReseedIterator

MultiThreaderType::Pointer	m_Threader

BSplineTransformIndexArrayType *	m_ThreaderBSplineTransformIndices

BSplineTransformWeightsType *	m_ThreaderBSplineTransformWeights

unsigned int *	m_ThreaderNumberOfMovingImageSamples

MultiThreaderParameterType	m_ThreaderParameter

TransformPointer *	m_ThreaderTransform

TransformPointer	m_Transform

bool	m_TransformIsBSpline

bool	m_UseAllPixels

bool	m_UseCachingOfBSplineWeights

bool	m_UseFixedImageIndexes

bool	m_UseFixedImageSamplesIntensityThreshold

bool	m_UseSequentialSampling

BooleanArrayType	m_WithinBSplineSupportRegionArray

bool	m_WithinThreadPostProcess

bool	m_WithinThreadPreProcess

Protected Attributes inherited from itk::LightObject
AtomicInt< int >	m_ReferenceCount

Static Protected Attributes inherited from itk::ImageToImageMetric< TFixedImage, TMovingImage >
static const unsigned int	DeformationSplineOrder = 3