itk::GaussianOperator< TPixel, VDimension, TAllocator > Class Template Reference

#include <itkGaussianOperator.h>

Detailed Description

template<typename TPixel, unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>
class itk::GaussianOperator< TPixel, VDimension, TAllocator >

A NeighborhoodOperator whose coefficients are a one dimensional, discrete Gaussian kernel.

GaussianOperator can be used to perform Gaussian blurring by taking its inner product with a Neighborhood (NeighborhoodIterator) that is swept across an image region. It is a directional operator. N successive applications oriented along each dimensional direction will effect separable, efficient, N-D Gaussian blurring of an image region.

GaussianOperator takes two parameters:

(1) The floating-point variance of the desired Gaussian function.

(2) The "maximum error" allowed in the discrete Gaussian function. "Maximum error" is defined as the difference between the area under the discrete Gaussian curve and the area under the continuous Gaussian. Maximum error affects the Gaussian operator size. Care should be taken not to make this value too small relative to the variance lest the operator size become unreasonably large.

References: The Gaussian kernel contained in this operator was described by Tony Lindeberg (Discrete Scale-Space Theory and the Scale-Space Primal Sketch. Dissertation. Royal Institute of Technology, Stockholm, Sweden. May 1991.).

Note

GaussianOperator does not have any user-declared "special member function", following the C++ Rule of Zero: the compiler will generate them if necessary.

See also

NeighborhoodOperator

NeighborhoodIterator

Neighborhood

ITK Sphinx Examples:

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Definition at line 69 of file itkGaussianOperator.h.

Inheritance diagram for itk::GaussianOperator< TPixel, VDimension, TAllocator >:

Collaboration diagram for itk::GaussianOperator< TPixel, VDimension, TAllocator >:

Public Types
using	Self = GaussianOperator
using	Superclass = NeighborhoodOperator< TPixel, VDimension, TAllocator >
Public Types inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >
using	PixelRealType = typename NumericTraits< TPixel >::RealType
using	PixelType = TPixel
using	Self = NeighborhoodOperator
using	SizeType = itk::Size< VDimension >
using	SliceIteratorType = SliceIterator< TPixel, Self >
using	Superclass = Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >
Public Types inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >
using	AllocatorType = NeighborhoodAllocator< TPixel >
using	ConstIterator = typename AllocatorType::const_iterator
using	DimensionValueType = unsigned int
using	Iterator = typename AllocatorType::iterator
using	NeighborIndexType = SizeValueType
using	OffsetType = Offset< VDimension >
using	PixelType = TPixel
using	RadiusType = itk::Size< VDimension >
using	Self = Neighborhood
using	SizeType = itk::Size< VDimension >
using	SizeValueType = typename SizeType::SizeValueType
using	SliceIteratorType = SliceIterator< TPixel, Self >

Public Member Functions
void	DebugOff () const
void	DebugOn () const
bool	GetDebug () const
double	GetMaximumError ()
unsigned int	GetMaximumKernelWidth () const
const char *	GetNameOfClass () const override
double	GetVariance ()
double	ModifiedBesselI (int, double)
double	ModifiedBesselI0 (double)
double	ModifiedBesselI1 (double)
void	PrintSelf (std::ostream &os, Indent indent) const override
void	SetDebug (bool debugFlag) const
void	SetMaximumError (const double max_error)
void	SetMaximumKernelWidth (unsigned int n)
void	SetVariance (const double variance)
Public Member Functions inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >
virtual void	CreateDirectional ()
virtual void	CreateToRadius (const SizeType &)
virtual void	CreateToRadius (const SizeValueType)
virtual void	FlipAxes ()
unsigned long	GetDirection () const
const char *	GetNameOfClass () const override
void	PrintSelf (std::ostream &os, Indent indent) const override
void	ScaleCoefficients (PixelRealType)
void	SetDirection (const unsigned long direction)
Public Member Functions inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >
NeighborIndexType	GetCenterNeighborhoodIndex () const
TPixel	GetCenterValue () const
virtual const char *	GetNameOfClass () const
virtual NeighborIndexType	GetNeighborhoodIndex (const OffsetType &) const
OffsetType	GetOffset (NeighborIndexType i) const
const SizeType	GetRadius () const
SizeValueType	GetRadius (DimensionValueType n) const
SizeType	GetSize () const
SizeValueType	GetSize (DimensionValueType n) const
std::slice	GetSlice (unsigned int) const
OffsetValueType	GetStride (DimensionValueType axis) const
	ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION (Self)
	Neighborhood ()=default
	Neighborhood (const Self &)=default
	Neighborhood (Self &&)=default
Self &	operator= (const Self &)=default
Self &	operator= (Self &&)=default
bool	operator== (const Self &other) const
void	Print (std::ostream &os) const
void	SetRadius (const SizeType &)
void	SetRadius (const SizeValueType)
NeighborIndexType	Size () const
virtual	~Neighborhood ()=default
Iterator	End ()
ConstIterator	End () const
Iterator	Begin ()
ConstIterator	Begin () const
TPixel &	operator[] (NeighborIndexType i)
const TPixel &	operator[] (NeighborIndexType i) const
TPixel &	GetElement (NeighborIndexType i)
TPixel &	operator[] (const OffsetType &o)
const TPixel &	operator[] (const OffsetType &o) const
void	SetRadius (const SizeValueType *rad)
AllocatorType &	GetBufferReference ()
const AllocatorType &	GetBufferReference () const

Protected Types
using	CoefficientVector = typename std::vector< PixelRealType >
Protected Types inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >
using	CoefficientVector = typename std::vector< PixelRealType >

Protected Member Functions
void	Fill (const CoefficientVector &coeff) override
CoefficientVector	GenerateCoefficients () override
Protected Member Functions inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >
virtual void	Fill (const CoefficientVector &)=0
virtual void	FillCenteredDirectional (const CoefficientVector &)
virtual CoefficientVector	GenerateCoefficients ()=0
void	InitializeToZero ()
Protected Member Functions inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >
virtual void	Allocate (NeighborIndexType i)
virtual void	ComputeNeighborhoodOffsetTable ()
virtual void	ComputeNeighborhoodStrideTable ()
virtual void	PrintSelf (std::ostream &, Indent) const
void	SetSize ()

Private Attributes
bool	m_Debug { false }
double	m_MaximumError { .01 }
unsigned int	m_MaximumKernelWidth { 30 }
double	m_Variance { 1 }

Additional Inherited Members
Static Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >
static constexpr unsigned int	NeighborhoodDimension

Member Typedef Documentation

CoefficientVector

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

using itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >::CoefficientVector = typename std::vector<PixelRealType>

protected

Type alias support for coefficient vector type. Necessary to fix bug in the microsoft VC++ compiler.

Definition at line 153 of file itkNeighborhoodOperator.h.

Self

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

using itk::GaussianOperator< TPixel, VDimension, TAllocator >::Self = GaussianOperator

Standard class type aliases.

Definition at line 74 of file itkGaussianOperator.h.

Superclass

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

using itk::GaussianOperator< TPixel, VDimension, TAllocator >::Superclass = NeighborhoodOperator<TPixel, VDimension, TAllocator>

Definition at line 75 of file itkGaussianOperator.h.

Member Function Documentation

DebugOff()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::DebugOff ( ) const

inline

Turn debugging output off.

Definition at line 164 of file itkGaussianOperator.h.

DebugOn()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::DebugOn ( ) const

inline

Turn debugging output on.

Definition at line 157 of file itkGaussianOperator.h.

Fill()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::Fill ( const CoefficientVector &  coeff )

inlineoverrideprotectedvirtual

Arranges coefficients spatially in the memory buffer.

Implements itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >.

Definition at line 202 of file itkGaussianOperator.h.

GenerateCoefficients()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

CoefficientVector itk::GaussianOperator< TPixel, VDimension, TAllocator >::GenerateCoefficients ( )

overrideprotectedvirtual

Calculates operator coefficients.

Implements itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >.

GetDebug()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

bool itk::GaussianOperator< TPixel, VDimension, TAllocator >::GetDebug ( ) const

inline

Get the value of the debug flag. Mimics the itk::Object interface so that itkDebugMacro can be used in selective printouts from Gaussian kernel generation.

Definition at line 150 of file itkGaussianOperator.h.

GetMaximumError()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::GetMaximumError ( )

inline

Returns the maximum error of the gaussian approximation. Maximum error is the difference between the area under the discrete Gaussian curve and the area under the continuous Gaussian. Maximum error affects the Gaussian operator size.

Definition at line 114 of file itkGaussianOperator.h.

GetMaximumKernelWidth()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

unsigned int itk::GaussianOperator< TPixel, VDimension, TAllocator >::GetMaximumKernelWidth ( ) const

inline

Returns the maximum allowed kernel width.

Definition at line 131 of file itkGaussianOperator.h.

GetNameOfClass()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

const char * itk::GaussianOperator< TPixel, VDimension, TAllocator >::GetNameOfClass ( ) const

overridevirtual

See also

LightObject::GetNameOfClass()

Reimplemented from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >.

GetVariance()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::GetVariance ( )

inline

Returns the variance of the Gaussian (scale) for the operator.

Definition at line 104 of file itkGaussianOperator.h.

ModifiedBesselI()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::ModifiedBesselI	(	int	,
		double
	)

Returns the value of the modified Bessel function Ik(x) at a point x>=0, where k>=2.

ModifiedBesselI0()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::ModifiedBesselI0

(

double

)

Returns the value of the modified Bessel function I0(x) at a point x >= 0.

ModifiedBesselI1()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::ModifiedBesselI1

(

double

)

Returns the value of the modified Bessel function I1(x) at a point x, x real.

PrintSelf()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::PrintSelf ( std::ostream &  , Indent    ) const

inlineoverridevirtual

Standard itk object method.

Reimplemented from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >.

Definition at line 137 of file itkGaussianOperator.h.

SetDebug()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::SetDebug ( bool  debugFlag ) const

inline

Set the value of the debug flag. A non-zero value turns debugging on.

Definition at line 171 of file itkGaussianOperator.h.

SetMaximumError()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::SetMaximumError ( const double  max_error )

inline

Sets the desired maximum error of the gaussian approximation. Maximum error is the difference between the area under the discrete Gaussian curve and the area under the continuous Gaussian. Maximum error affects the Gaussian operator size. The value must be between 0.0 and 1.0.

Definition at line 92 of file itkGaussianOperator.h.

SetMaximumKernelWidth()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::SetMaximumKernelWidth ( unsigned int  n )

inline

Sets a limit for growth of the kernel. Small maximum error values with large variances will yield very large kernel sizes. This value can be used to truncate a kernel in such instances. A warning will be given on truncation of the kernel.

Definition at line 124 of file itkGaussianOperator.h.

SetVariance()

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

void itk::GaussianOperator< TPixel, VDimension, TAllocator >::SetVariance ( const double  variance )

inline

Sets the desired variance of the Gaussian kernel.

Definition at line 82 of file itkGaussianOperator.h.

Member Data Documentation

m_Debug

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

bool itk::GaussianOperator< TPixel, VDimension, TAllocator >::m_Debug { false }

mutableprivate

Enable/disable kernel generation debug warnings

Definition at line 221 of file itkGaussianOperator.h.

m_MaximumError

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::m_MaximumError { .01 }

private

Difference between the areas under the curves of the continuous and discrete Gaussian functions.

Definition at line 213 of file itkGaussianOperator.h.

m_MaximumKernelWidth

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

unsigned int itk::GaussianOperator< TPixel, VDimension, TAllocator >::m_MaximumKernelWidth { 30 }

private

Maximum kernel size allowed. This value is used to truncate a kernel that has grown too large. A warning is given when the specified maximum error causes the kernel to exceed this size.

Definition at line 218 of file itkGaussianOperator.h.

m_Variance

template<typename TPixel , unsigned int VDimension = 2, typename TAllocator = NeighborhoodAllocator<TPixel>>

double itk::GaussianOperator< TPixel, VDimension, TAllocator >::m_Variance { 1 }

private

Desired variance of the discrete Gaussian function.

Definition at line 209 of file itkGaussianOperator.h.

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

• itkGaussianOperator.h