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itk::FiniteDifferenceFunction< TImageType > Class Template Reference
[Functions]

#include <itkFiniteDifferenceFunction.h>

Inheritance diagram for itk::FiniteDifferenceFunction:

[legend]Collaboration diagram for itk::FiniteDifferenceFunction< TImageType >:

[legend]List of all members.

Public Types
typedef FiniteDifferenceFunction	Self
typedef LightObject	Superclass
typedef SmartPointer< Self >	Pointer
typedef SmartPointer< const Self >	ConstPointer
typedef TImageType	ImageType
typedef ImageType::PixelType	PixelType
typedef double	TimeStepType
typedef ZeroFluxNeumannBoundaryCondition< ImageType >	DefaultBoundaryConditionType
typedef ConstNeighborhoodIterator< TImageType >::RadiusType	RadiusType
typedef ConstNeighborhoodIterator< TImageType, DefaultBoundaryConditionType >	NeighborhoodType
typedef Vector< float, itkGetStaticConstMacro(ImageDimension)	FloatOffsetType )
Public Methods
virtual const char *	GetClassName () const
	itkStaticConstMacro (ImageDimension, unsigned int, ImageType::ImageDimension)
virtual void	InitializeIteration ()
virtual PixelType	ComputeUpdate (const NeighborhoodType &neighborhood, void *globalData, const FloatOffsetType &offset=FloatOffsetType(0.0)) const=0
void	SetRadius (const RadiusType &r)
const RadiusType &	GetRadius () const
virtual TimeStepType	ComputeGlobalTimeStep (void *GlobalData) const=0
virtual void *	GetGlobalDataPointer () const=0
virtual void	ReleaseGlobalDataPointer (void *GlobalData) const=0
Protected Methods
	FiniteDifferenceFunction ()
	~FiniteDifferenceFunction ()
void	PrintSelf (std::ostream &os, Indent indent) const
Protected Attributes
RadiusType	m_Radius

Detailed Description

template<class TImageType>
class itk::FiniteDifferenceFunction< TImageType >

This class is a component object of the finite difference solver hierarchy (see itkFiniteDifferenceImageFilter). It defines a generic interface for a function object that computes a single scalar value from a neighborhood of values. Examples of the application of this class are the various flavors of AnisotropicDiffusionFunctions and LevelSetFunction objects.

These functions calculate the incremental change at a pixel in the solution image from one iteration of the p.d.e. solver to the next.

Subclasses of FiniteDifferenceImageFilter (solvers) call the ComputeUpdate() method of this class to compute at each . in . Because the size of the time step for each iteration of the p.d.e. solution depends on the particular calculations done, this function object is also responsible for computing that time step (see ComputeGlobalTimeStep).

How to use this class: FiniteDifferenceFunction must be subclassed to add functionality for ComputeUpdate, ComputeGlobalTimeStep, and Get/ReleaseGlobalDataPointer.

A note on thread safety.: The ComputeUpdate() methods of this filter are declared as const to enforce thread-safety during execution of FiniteDifferenceImageFilter solver algorithms. The InitializeIteration() method is intended to provide a safe way to modify the state of the object between threaded calculations of solvers.

Todo:: Possibly subclass this object from Function. Stumbling blocks here are the specialized api of FiniteDifferenceFunction.

Definition at line 62 of file itkFiniteDifferenceFunction.h.

Member Typedef Documentation

template<class TImageType>

typedef ZeroFluxNeumannBoundaryCondition<ImageType> itk::FiniteDifferenceFunction< TImageType >::DefaultBoundaryConditionType

The default boundary condition for finite difference functions that is used unless overridden in the Evaluate() method.
Definition at line 89 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

typedef Vector<float,itkGetStaticConstMacro(ImageDimension) itk::FiniteDifferenceFunction< TImageType >::FloatOffsetType)

A floating point offset from an image grid location. Used for interpolation among grid values in a neighborhood.
Reimplemented in itk::BinaryMinMaxCurvatureFlowFunction< TImage >, itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::GeodesicActiveContourLevelSetFunction< TImageType, TFeatureImageType >, itk::MinMaxCurvatureFlowFunction< TImage >, itk::ShapeDetectionLevelSetFunction< TImageType, TFeatureImageType >, itk::AnisotropicDiffusionFunction< TImage >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, itk::VectorGradientNDAnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, itk::LevelSetFunctionBase< TImageType >, itk::SegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::LevelSetFunction< OutputImageType >, itk::LevelSetFunctionBase< OutputImageType >, and itk::SegmentationLevelSetFunction< OutputImageType, FeatureImageType >.
Definition at line 100 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

typedef TImageType itk::FiniteDifferenceFunction< TImageType >::ImageType

Extract some parameters from the image type
Reimplemented in itk::BinaryMinMaxCurvatureFlowFunction< TImage >, itk::CannySegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::CurvatureFlowFunction< TImage >, itk::GeodesicActiveContourLevelSetFunction< TImageType, TFeatureImageType >, itk::LaplacianSegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::MinMaxCurvatureFlowFunction< TImage >, itk::ShapeDetectionLevelSetFunction< TImageType, TFeatureImageType >, itk::ThresholdSegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::AnisotropicDiffusionFunction< TImage >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::ScalarAnisotropicDiffusionFunction< TImage >, itk::VectorAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, itk::VectorGradientNDAnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, itk::LevelSetFunctionBase< TImageType >, itk::SegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::LevelSetFunction< OutputImageType >, itk::LevelSetFunctionBase< OutputImageType >, and itk::SegmentationLevelSetFunction< OutputImageType, FeatureImageType >.
Definition at line 77 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

typedef double itk::FiniteDifferenceFunction< TImageType >::TimeStepType

Define the TimeStepType to always be double.
Reimplemented in itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::AnisotropicDiffusionFunction< TImage >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::ScalarAnisotropicDiffusionFunction< TImage >, itk::VectorAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, itk::VectorGradientNDAnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, itk::LevelSetFunctionBase< TImageType >, itk::LevelSetFunction< OutputImageType >, and itk::LevelSetFunctionBase< OutputImageType >.
Definition at line 84 of file itkFiniteDifferenceFunction.h.

Constructor & Destructor Documentation

template<class TImageType>

itk::FiniteDifferenceFunction< TImageType >::FiniteDifferenceFunction ( ) [inline, protected]

Definition at line 167 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

itk::FiniteDifferenceFunction< TImageType >::~FiniteDifferenceFunction ( ) [inline, protected]

Definition at line 168 of file itkFiniteDifferenceFunction.h.

Member Function Documentation

template<class TImageType>

virtual TimeStepType itk::FiniteDifferenceFunction< TImageType >::ComputeGlobalTimeStep ( void * GlobalData ) const [pure virtual]

Computes the time step for an update given a global data structure. The data used in the computation may take different forms depending on the nature of the equations. This global data cannot be kept in the instance of the equation object itself since the equation object must remain stateless for thread safety. The global data is therefore managed for each thread by the finite difference solver filters.
Implemented in itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::AnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, and itk::LevelSetFunction< OutputImageType >.

template<class TImageType>

virtual PixelType itk::FiniteDifferenceFunction< TImageType >::ComputeUpdate ( const NeighborhoodType & neighborhood,

void * globalData,

const FloatOffsetType & offset = FloatOffsetType(0.0)

) const [pure virtual]

This method is called by a finite difference solver image filter at each pixel that does not lie on a data set boundary. The width of the data set boundary is defined by the width of the neighborhood being evaluated.
The neighborhood argument is the neighborhood data. The globalData argument is a pointer to a data structure that holds values that need to be persistent across calls to this function, but cannot be stored in the function object itself for thread-safety reasons. Examples are values needed to compute the time-step for an iteration of the solver.
See also:
InitializeIteration , ComputeGlobalTimeStep

Implemented in itk::BinaryMinMaxCurvatureFlowFunction< TImage >, itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::MinMaxCurvatureFlowFunction< TImage >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, itk::VectorGradientNDAnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, and itk::LevelSetFunction< OutputImageType >.

template<class TImageType>

virtual void* itk::FiniteDifferenceFunction< TImageType >::GetGlobalDataPointer ( ) const [pure virtual]

Returns a pointer to a global data structure that is passed to this object from the solver at each calculation. The idea is that the solver holds the state of any global values needed to calculate the time step, while the equation object performs the actual calculations.
The global data should also be initialized in this method.
Implemented in itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::AnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, and itk::LevelSetFunction< OutputImageType >.

template<class TImageType>

const RadiusType& itk::FiniteDifferenceFunction< TImageType >::GetRadius ( ) const [inline]

Returns the radius of the neighborhood this FiniteDifferenceFunction needs to perform its calculations.
Definition at line 139 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

virtual void itk::FiniteDifferenceFunction< TImageType >::InitializeIteration ( ) [inline, virtual]

This method allows the function to set its state before each iteration of the finite difference solver (image filter) that uses it. This is a thread-safe time to manipulate the object's state.
An example of how this can be used: the Anisotropic diffusion class of FiniteDifferenceFunctions use this method to pre-calculate an average gradient magnitude across the entire image region. This value is set in the function object and used by the ComputeUpdate methods that are called at each pixel as a constant.
Reimplemented in itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, and itk::VectorGradientNDAnisotropicDiffusionFunction< TImage >.
Definition at line 111 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

itk::FiniteDifferenceFunction< TImageType >::itkStaticConstMacro ( ImageDimension ,

unsigned int,

ImageType::ImageDimension

)

Save image dimension.

template<class TImageType>

void itk::FiniteDifferenceFunction< TImageType >::PrintSelf ( std::ostream & os,

Indent indent

) const [inline, 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::LightObject.
Reimplemented in itk::CannySegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::GeodesicActiveContourLevelSetFunction< TImageType, TFeatureImageType >, itk::LaplacianSegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::PDEDeformableRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::ShapeDetectionLevelSetFunction< TImageType, TFeatureImageType >, itk::ThresholdSegmentationLevelSetFunction< TImageType, TFeatureImageType >, itk::AnisotropicDiffusionFunction< TImage >, itk::CurvatureNDAnisotropicDiffusionFunction< TImage >, itk::GradientNDAnisotropicDiffusionFunction< TImage >, itk::ScalarAnisotropicDiffusionFunction< TImage >, itk::VectorAnisotropicDiffusionFunction< TImage >, itk::VectorCurvatureNDAnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, itk::LevelSetFunctionBase< TImageType >, itk::LevelSetFunction< OutputImageType >, and itk::LevelSetFunctionBase< OutputImageType >.
Definition at line 169 of file itkFiniteDifferenceFunction.h.

template<class TImageType>

virtual void itk::FiniteDifferenceFunction< TImageType >::ReleaseGlobalDataPointer ( void * GlobalData ) const [pure virtual]

When the finite difference solver filter has finished using a global data pointer, it passes it to this method, which frees the memory.
The solver cannot free the memory because it does not know the type to which the pointer points.
Implemented in itk::CurvatureFlowFunction< TImage >, itk::DemonsRegistrationFunction< TFixedImage, TMovingImage, TDeformationField >, itk::AnisotropicDiffusionFunction< TImage >, itk::LevelSetFunction< TImageType >, and itk::LevelSetFunction< OutputImageType >.

template<class TImageType>

void itk::FiniteDifferenceFunction< TImageType >::SetRadius ( const RadiusType & r ) [inline]

Sets the radius of the neighborhood this FiniteDifferenceFunction needs to perform its calculations.
Definition at line 134 of file itkFiniteDifferenceFunction.h.

Member Data Documentation

template<class TImageType>

RadiusType itk::FiniteDifferenceFunction< TImageType >::m_Radius [protected]

Definition at line 175 of file itkFiniteDifferenceFunction.h.
Referenced by itk::FiniteDifferenceFunction< TDeformationField >::GetRadius(), itk::FiniteDifferenceFunction< TDeformationField >::PrintSelf(), and itk::FiniteDifferenceFunction< TDeformationField >::SetRadius().

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

itkFiniteDifferenceFunction.h

Generated at Fri May 21 01:26:22 2004 for ITK by

itk::FiniteDifferenceFunction< TImageType > Class Template Reference [Functions]

Public Types

Public Methods

Protected Methods

Protected Attributes