itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage > Class Template Reference
[Similarity Metrics of Registration Methods]

Computes the mutual information between two images to be registered. More...

#include <itkMutualInformationImageToImageMetric.h>

Inheritance diagram for itk::MutualInformationImageToImageMetric:

[legend]Collaboration diagram for itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >:

[legend]List of all members.

Public Types
typedef MutualInformationImageToImageMetric	Self
typedef ImageToImageMetric< TFixedImage, TMovingImage >	Superclass
typedef SmartPointer< Self >	Pointer
typedef SmartPointer< const Self >	ConstPointer
typedef Superclass::TransformType	TransformType
typedef Superclass::TransformPointer	TransformPointer
typedef Superclass::TransformJacobianType	TransformJacobianType
typedef Superclass::InterpolatorType	InterpolatorType
typedef Superclass::MeasureType	MeasureType
typedef Superclass::DerivativeType	DerivativeType
typedef Superclass::ParametersType	ParametersType
typedef Superclass::FixedImageType	FixedImageType
typedef Superclass::MovingImageType	MovingImageType
typedef Superclass::FixedImageConstPointer	FixedImageConstPointer
typedef Superclass::MovingImageConstPointer	MovingImageCosntPointer
typedef FixedImageType::IndexType	FixedImageIndexType
typedef FixedImageIndexType::IndexValueType	FixedImageIndexValueType
typedef MovingImageType::IndexType	MovingImageIndexType
typedef TransformType::InputPointType	FixedImagePointType
typedef TransformType::OutputPointType	MovingImagePointType
Public Methods
virtual const char *	GetClassName () const
	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)
virtual unsigned int	GetNumberOfSpatialSamples () const
virtual void	SetMovingImageStandardDeviation (double _arg)
virtual double	GetMovingImageStandardDeviation () const
virtual void	SetFixedImageStandardDeviation (double _arg)
virtual double	GetFixedImageStandardDeviation ()
virtual void	SetKernelFunction (KernelFunction *_arg)
virtual KernelFunction *	GetKernelFunction ()
Static Public Methods
Pointer	New ()
Protected Methods
	MutualInformationImageToImageMetric ()
virtual	~MutualInformationImageToImageMetric ()
void	PrintSelf (std::ostream &os, Indent indent) const

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Detailed Description

template<class TFixedImage, class 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 KernelFunction 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:

KernelFunction , GaussianKernelFunction

Definition at line 90 of file itkMutualInformationImageToImageMetric.h.

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Member Typedef Documentation

template<class TFixedImage, class TMovingImage> typedef SmartPointer<const Self> itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::ConstPointer

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 99 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::DerivativeType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::DerivativeType

Type of the derivative. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 113 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::FixedImageConstPointer itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::FixedImageConstPointer

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 117 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef FixedImageType::IndexType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::FixedImageIndexType

Index and Point typedef support. Definition at line 121 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef FixedImageIndexType::IndexValueType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::FixedImageIndexValueType

Definition at line 122 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef TransformType::InputPointType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::FixedImagePointType

Definition at line 124 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::FixedImageType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::FixedImageType

Type of the fixed Image. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 115 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::InterpolatorType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::InterpolatorType

Type of the Interpolator Base class Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 111 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::MeasureType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MeasureType

Type of the measure. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 112 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::MovingImageConstPointer itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MovingImageCosntPointer

Definition at line 118 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef MovingImageType::IndexType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MovingImageIndexType

Definition at line 123 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef TransformType::OutputPointType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MovingImagePointType

Definition at line 125 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::MovingImageType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MovingImageType

Type of the moving Image. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 116 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::ParametersType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::ParametersType

Type of the parameters. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 114 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef SmartPointer<Self> itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::Pointer

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 98 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef MutualInformationImageToImageMetric itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::Self

Standard class typedefs. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 96 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef ImageToImageMetric< TFixedImage, TMovingImage > itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::Superclass

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 97 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::TransformJacobianType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::TransformJacobianType

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 110 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::TransformPointer itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::TransformPointer

Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 109 of file itkMutualInformationImageToImageMetric.h.

template<class TFixedImage, class TMovingImage> typedef Superclass::TransformType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::TransformType

Types inherited from Superclass. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >. Definition at line 108 of file itkMutualInformationImageToImageMetric.h.

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Constructor & Destructor Documentation

template<class TFixedImage, class TMovingImage> itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::MutualInformationImageToImageMetric (    )  [protected]

template<class TFixedImage, class TMovingImage> virtual itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::~MutualInformationImageToImageMetric (    )  [inline, protected, virtual]

Definition at line 180 of file itkMutualInformationImageToImageMetric.h.

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Member Function Documentation

template<class TFixedImage, class TMovingImage> virtual const char* itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetClassName (    )  const [virtual]

Run-time type information (and related methods). Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >.

template<class TFixedImage, class TMovingImage> void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetDerivative (  const ParametersType &    parameters, DerivativeType &    Derivative )  const [virtual]

Get the derivatives of the match measure. Implements itk::SingleValuedCostFunction.

template<class TFixedImage, class TMovingImage> virtual double itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetFixedImageStandardDeviation (    )  [virtual]

Set/Get the fixed image intensitiy standard deviation. This defines the kernel bandwidth used in the joint probability distribution calculation. Default value is 0.4 which works well for image intensities normalized to a mean of 0 and standard deviation of 1.0. Value is clamped to be always greater than zero.

template<class TFixedImage, class TMovingImage> virtual KernelFunction* itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetKernelFunction (    )  [virtual]

Set/Get the kernel function. This is used to calculate the joint probability distribution. Default is the GaussianKernelFunction.

template<class TFixedImage, class TMovingImage> virtual double itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetMovingImageStandardDeviation (    )  const [virtual]

Set/Get the moving image intensitiy standard deviation. This defines the kernel bandwidth used in the joint probability distribution calculation. Default value is 0.4 which works well for image intensities normalized to a mean of 0 and standard deviation of 1.0. Value is clamped to be always greater than zero.

template<class TFixedImage, class TMovingImage> virtual unsigned int itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetNumberOfSpatialSamples (    )  const [virtual]

Get the number of spatial samples.

template<class TFixedImage, class TMovingImage> MeasureType itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetValue (  const ParametersType &    parameters )  const [virtual]

Get the value. Implements itk::SingleValuedCostFunction.

template<class TFixedImage, class TMovingImage> void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::GetValueAndDerivative (  const ParametersType &    parameters, MeasureType &    Value, DerivativeType &    Derivative )  const [virtual]

Get the value and derivatives for single valued optimizers. Reimplemented from itk::SingleValuedCostFunction.

template<class TFixedImage, class TMovingImage> itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::itkStaticConstMacro (  MovingImageDimension   , unsigned    int, MovingImageType::ImageDimension    )

Enum of the moving image dimension.

template<class TFixedImage, class TMovingImage> Pointer itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::New (    )  [static]

Method for creation through the object factory. Reimplemented from itk::Object.

template<class TFixedImage, class TMovingImage> void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::PrintSelf (  std::ostream &    os, Indent    indent )  const [protected, virtual]

Methods invoked by Print() to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes. Reimplemented from itk::ImageToImageMetric< TFixedImage, TMovingImage >.

template<class TFixedImage, class TMovingImage> virtual void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::SetFixedImageStandardDeviation (  double    _arg )  [virtual]

Set/Get the fixed image intensitiy standard deviation. This defines the kernel bandwidth used in the joint probability distribution calculation. Default value is 0.4 which works well for image intensities normalized to a mean of 0 and standard deviation of 1.0. Value is clamped to be always greater than zero.

template<class TFixedImage, class TMovingImage> virtual void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::SetKernelFunction (  KernelFunction *    _arg )  [virtual]

Set/Get the kernel function. This is used to calculate the joint probability distribution. Default is the GaussianKernelFunction.

template<class TFixedImage, class TMovingImage> virtual void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::SetMovingImageStandardDeviation (  double    _arg )  [virtual]

Set/Get the moving image intensitiy standard deviation. This defines the kernel bandwidth used in the joint probability distribution calculation. Default value is 0.4 which works well for image intensities normalized to a mean of 0 and standard deviation of 1.0. Value is clamped to be always greater than zero.

template<class TFixedImage, class TMovingImage> void itk::MutualInformationImageToImageMetric< TFixedImage, TMovingImage >::SetNumberOfSpatialSamples (  unsigned int    num )

Set the number of spatial samples. This is the number of image samples used to calculate the joint probability distribution. The number of spatial samples is clamped to be a minimum of 1. Default value is 50.

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The documentation for this class was generated from the following file:

• itkMutualInformationImageToImageMetric.h

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