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

#include <itkSobelOperator.h>

Detailed Description

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

A NeighborhoodOperator for performing a directional Sobel edge-detection operation at a pixel location.

SobelOperator is a directional NeighborhoodOperator that should be applied a NeighborhoodIterator using the NeighborhoodInnerProduct method. To create the operator:

1) Set the direction by calling

SetDirection 

2) call

constexpr  auto radius = itk::Size<2>::Filled(1);
sobelOperator.CreateToRadius(radius);

3) You may optionally scale the coefficients of this operator using the

ScaleCoefficients 

method. This is useful if you want to take the spacing of the image into account when computing the edge strength. Apply the scaling only after calling to

CreateToRadius 

.

The Sobel Operator in vertical direction for 2 dimensions is

*             -1  -2  -1
*             0    0   0
*             1    2   1
*
* 

The Sobel Operator in horizontal direction is for 2 dimensions is

*             -1   0   1
*             -2   0   2
*             -1   0   1
* 

The current implementation of the Sobel operator is for 2 and 3 dimensions only. The ND version is planned for future releases.

The Sobel operator in 3D has the following kernel, when using legacy coefficients:

* -1 -3 -1   0 0 0  1 3 1
* -3 -6 -3   0 0 0  3 6 3
* -1 -3 -1   0 0 0  1 3 1
*
*    x-1       x     x+1
* 

And it has the following kernel, when it is not using legacy coefficients:

* -1 -2 -1   0 0 0  1 2 1
* -2 -4 -2   0 0 0  2 4 2
* -1 -2 -1   0 0 0  1 2 1
*
*    x-1       x     x+1
* 

The x kernel is just rotated as required to obtain the kernel in the y and z directions.

Note

SobelOperator 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

Neighborhood

ForwardDifferenceOperator

BackwardDifferenceOperator

ITK Sphinx Examples:

• All ITK Sphinx Examples

• Create Sobel Kernel

Examples

Examples/Iterators/NeighborhoodIterators2.cxx, and Examples/Iterators/NeighborhoodIterators3.cxx.

Definition at line 103 of file itkSobelOperator.h.

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

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

Public Types
using	Self = SobelOperator
using	Superclass = NeighborhoodOperator<TPixel, VDimension, TAllocator>
Public Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
using	PixelRealType = typename NumericTraits<TPixel>::RealType
using	PixelType = TPixel
using	Self = NeighborhoodOperator
using	SliceIteratorType = SliceIterator<TPixel, Self>
using	Superclass = Neighborhood<TPixel, VDimension, TAllocator>
Public Types inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
using	AllocatorType = TAllocator
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	CreateDirectional () override
virtual const char *	GetNameOfClass () const
bool	IsUsingLegacyCoefficients () const
void	UseLegacyCoefficients (const bool useLegacyCoefficients)
Public Member Functions inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
virtual void	CreateToRadius (const SizeType &)
virtual void	CreateToRadius (const SizeValueType)
virtual void	FlipAxes ()
unsigned int	GetDirection () const
void	PrintSelf (std::ostream &os, Indent indent) const override
void	ScaleCoefficients (PixelRealType)
void	SetDirection (const unsigned int direction)
Public Member Functions inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
NeighborIndexType	GetCenterNeighborhoodIndex () const
TPixel	GetCenterValue () 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 *rad)
void	SetRadius (const SizeValueType)
NeighborIndexType	Size () const
virtual	~Neighborhood ()=default
Iterator	End ()
Iterator	Begin ()
ConstIterator	End () const
ConstIterator	Begin () const
TPixel &	operator[] (NeighborIndexType i)
const TPixel &	operator[] (NeighborIndexType i) const
TPixel &	GetElement (NeighborIndexType i)
AllocatorType &	GetBufferReference ()
const AllocatorType &	GetBufferReference () const
TPixel &	operator[] (const OffsetType &o)
const TPixel &	operator[] (const OffsetType &o) const

Protected Types
using	CoefficientVector
Protected Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
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, VDimension, TAllocator >
virtual void	FillCenteredDirectional (const CoefficientVector &)
void	InitializeToZero ()
Protected Member Functions inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
virtual void	Allocate (NeighborIndexType i)
virtual void	ComputeNeighborhoodOffsetTable ()
virtual void	ComputeNeighborhoodStrideTable ()
void	SetSize ()

Private Attributes
bool	m_UseLegacyCoefficients { true }

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

Member Typedef Documentation

CoefficientVector

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

using itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >::CoefficientVector

protected

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

Definition at line 152 of file itkNeighborhoodOperator.h.

Self

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

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

Standard class type aliases.

Definition at line 107 of file itkSobelOperator.h.

Superclass

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

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

Definition at line 108 of file itkSobelOperator.h.

Member Function Documentation

CreateDirectional()

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

void itk::SobelOperator< TPixel, VDimension, TAllocator >::CreateDirectional ( )

inlineoverridevirtual

Creates the operator with length only in the specified direction. The radius of the operator will be 0 except along the axis on which the operator will work.

See also

CreateToRadius

FillCenteredDirectional

SetDirection()

GetDirection()

Reimplemented from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.

Examples

Examples/Iterators/NeighborhoodIterators2.cxx, and Examples/Iterators/NeighborhoodIterators3.cxx.

Definition at line 120 of file itkSobelOperator.h.

References itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >::CreateToRadius().

Fill()

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

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

overrideprotectedvirtual

Arranges coefficients spatially in the memory buffer.

Implements itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.

GenerateCoefficients()

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

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

overrideprotectedvirtual

Calculates operator coefficients.

Implements itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.

GetNameOfClass()

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

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

virtual

See also

LightObject::GetNameOfClass()

Reimplemented from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.

IsUsingLegacyCoefficients()

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

bool itk::SobelOperator< TPixel, VDimension, TAllocator >::IsUsingLegacyCoefficients ( ) const

inline

Tells whether or not GenerateCoefficients() returns the legacy coordinate values, compatible with ITK <= 5.4.

Definition at line 141 of file itkSobelOperator.h.

References m_UseLegacyCoefficients.

UseLegacyCoefficients()

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

void itk::SobelOperator< TPixel, VDimension, TAllocator >::UseLegacyCoefficients ( const bool useLegacyCoefficients )

inline

Creates the operator with a specified radius ("square", same length on each side). The spatial location of the coefficients within the operator is defined by the subclass implementation of the Fill method.

See also

CreateDirectional

Fill Allows specifying whether or not GenerateCoefficients() should return the legacy coordinate values, compatible with ITK <= 5.4.

Definition at line 134 of file itkSobelOperator.h.

References m_UseLegacyCoefficients.

Member Data Documentation

m_UseLegacyCoefficients

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

bool itk::SobelOperator< TPixel, VDimension, TAllocator >::m_UseLegacyCoefficients { true }

private

Definition at line 161 of file itkSobelOperator.h.

Referenced by IsUsingLegacyCoefficients(), and UseLegacyCoefficients().

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

• itkSobelOperator.h