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

#include <itkSobelOperator.h>

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

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

Detailed Description

template<class TPixel, unsigned int VDimension = 2, class 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

itk::Size<2> radius;
radius.Fill(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 horizonal 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 extension to 3D is from the publication "Irwin Sobel. An Isotropic 3x3x3 Volume Gradient Operator. Technical report, Hewlett-Packard Laboratories, April 1995."

The Sobel operator in 3D has the kernel

* -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
* 

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

See Also

NeighborhoodOperator

Neighborhood

ForwardDifferenceOperator

BackwardDifferenceOperator

Wiki Examples:

• All Examples

• Create the Sobel kernel

Definition at line 96 of file itkSobelOperator.h.

Public Types
typedef SobelOperator	Self
typedef NeighborhoodOperator < TPixel, VDimension, TAllocator >	Superclass
Public Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
typedef NumericTraits< TPixel > ::RealType	PixelRealType
typedef TPixel	PixelType
typedef NeighborhoodOperator	Self
typedef Superclass::SizeType	SizeType
typedef SliceIterator< TPixel, Self >	SliceIteratorType
typedef Neighborhood< TPixel, VDimension, TAllocator >	Superclass
Public Types inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
typedef TAllocator	AllocatorType
typedef AllocatorType::const_iterator	ConstIterator
typedef unsigned int	DimensionValueType
typedef AllocatorType::iterator	Iterator
typedef SizeValueType	NeighborIndexType
typedef Offset< VDimension >	OffsetType
typedef TPixel	PixelType
typedef Neighborhood	Self
typedef SizeType::SizeValueType	SizeValueType
typedef SliceIterator< TPixel, Self >	SliceIteratorType

Public Member Functions
virtual void	CreateDirectional ()
virtual const char *	GetNameOfClass () const
	SobelOperator ()
	SobelOperator (const Self &other)
Self &	operator= (const Self &other)
virtual void	PrintSelf (std::ostream &os, Indent i) const
Public Member Functions inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
virtual void	CreateToRadius (const SizeType &)
virtual void	CreateToRadius (const SizeValueType)
virtual void	FlipAxes ()
unsigned long	GetDirection () const
	NeighborhoodOperator ()
	NeighborhoodOperator (const Self &orig)
void	ScaleCoefficients (PixelRealType)
void	SetDirection (const unsigned long &direction)
Self &	operator= (const Self &orig)
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
SizeValueType	GetSize (DimensionValueType n) const
SizeType	GetSize () const
std::slice	GetSlice (unsigned int) const
OffsetValueType	GetStride (DimensionValueType axis) const
	Neighborhood (const Self &other)
bool	operator!= (const Self &other) const
Self &	operator= (const Self &other)
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 ()
	Neighborhood ()
Iterator	End ()
Iterator	Begin ()
ConstIterator	End () const
ConstIterator	Begin () const
TPixel &	operator[] (NeighborIndexType i)
const TPixel &	operator[] (NeighborIndexType i) const
TPixel &	GetElement (NeighborIndexType i)
void	SetRadius (const SizeValueType *rad)
AllocatorType &	GetBufferReference ()
const AllocatorType &	GetBufferReference () const
TPixel &	operator[] (const OffsetType &o)
const TPixel &	operator[] (const OffsetType &o) const

Protected Types
typedef Superclass::CoefficientVector	CoefficientVector
typedef Superclass::PixelType	PixelType
Protected Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >
typedef std::vector < PixelRealType >	CoefficientVector

Protected Member Functions
void	Fill (const CoefficientVector &c)
CoefficientVector	GenerateCoefficients ()
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 ()

Additional Inherited Members
Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
typedef::itk::Size< VDimension >	RadiusType
typedef::itk::Size< VDimension >	SizeType
Static Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, TAllocator >
static const unsigned int	NeighborhoodDimension = VDimension

Member Typedef Documentation

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

typedef Superclass::CoefficientVector itk::SobelOperator< TPixel, VDimension, TAllocator >::CoefficientVector

protected

Typedef support for coefficient vector type. Necessary to work around compiler bug on VC++.

Definition at line 153 of file itkSobelOperator.h.

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

typedef Superclass::PixelType itk::SobelOperator< TPixel, VDimension, TAllocator >::PixelType

protected

Definition at line 154 of file itkSobelOperator.h.

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

typedef SobelOperator itk::SobelOperator< TPixel, VDimension, TAllocator >::Self

Standard typedefs

Definition at line 102 of file itkSobelOperator.h.

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

typedef NeighborhoodOperator< TPixel, VDimension, TAllocator > itk::SobelOperator< TPixel, VDimension, TAllocator >::Superclass

Definition at line 103 of file itkSobelOperator.h.

Constructor & Destructor Documentation

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

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

inline

Definition at line 107 of file itkSobelOperator.h.

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

itk::SobelOperator< TPixel, VDimension, TAllocator >::SobelOperator ( const Self &  other )

inline

Definition at line 108 of file itkSobelOperator.h.

Member Function Documentation

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

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

inlinevirtual

Creates the operator with length only in the specified direction. For the Sobel operator, this 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 >.

Definition at line 117 of file itkSobelOperator.h.

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

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

protectedvirtual

Arranges coefficients spatially in the memory buffer.

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

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

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

protectedvirtual

Calculates operator coefficients.

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

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

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

virtual

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

Self& itk::SobelOperator< TPixel, VDimension, TAllocator >::operator= ( const Self &  other )

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 Assignment operator

Definition at line 131 of file itkSobelOperator.h.

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

virtual void itk::SobelOperator< TPixel, VDimension, TAllocator >::PrintSelf ( std::ostream &  os, Indent  i  ) const

inlinevirtual

Prints some debugging information

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

Definition at line 141 of file itkSobelOperator.h.

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

• itkSobelOperator.h