Detailed Description

template<unsigned int VDimension>
class itk::FlatStructuringElement< VDimension >

A class to support a variety of flat structuring elements, including versions created by decomposition of lines.

FlatStructuringElement provides several static methods, which can be used to create a structuring element with a particular shape, size, etc. Currently, those methods enable the creation of the following structuring elements: ball, box, cross, annulus, or polygon. Polygons are available as fast approximations of balls using line decompositions. Boxes also use line decompositions.

"Flat" refers to binary as opposed to grayscale structuring elements. Flat structuring elements can be used for both binary and grayscale images.

A Neighborhood has an N-dimensional radius. The radius is defined separately for each dimension as the number of pixels that the neighborhood extends outward from the center pixel. For example, a 2D Neighborhood object with a radius of 2x3 has sides of length 5x7. However, in the case of balls and annuli, this definition is slightly different from the parametric definition of those objects. For example, an ellipse of radius 2x3 has a diameter of 4x6, not 5x7. To have a diameter of 5x7, the radius would need to increase by 0.5 in each dimension. Thus, the "radius" of the neighborhood and the "radius" of the object should be distinguished.

To accomplish this, the "ball" and "annulus" structuring elements have an optional flag called "radiusIsParametric" (off by default). Setting this flag to true will use the parametric definition of the object and will generate structuring elements with more accurate areas, which can be especially important when morphological operations are intended to remove or retain objects of particular sizes. When the mode is turned off (default), the radius is the same, but the object diameter is set to (radius*2)+1, which is the size of the neighborhood region. Thus, the original ball and annulus structuring elements have a systematic bias in the radius of +0.5 voxels in each dimension relative to the parametric definition of the radius. Thus, we recommend turning this mode on for more accurate structuring elements, but this mode is turned off by default for backward compatibility.

As an example, a 3D ball of radius 5 should have an area of 523. With this mode turned on, the number of "on" pixels is 515 (error 1.6%), but with it turned off, the area is 739 (error 41%). For a 3D annulus of radius 5 and thickness 2, the area should be 410. With this mode turned on, the area is 392 (error 4.5%), but when turned off it is 560 (error 36%). This same trend holds for balls and annuli of any radius or dimension. For more detailed experiments with this mode, please refer to the results of the test itkFlatStructuringElementTest.cxx or the wiki example.

Wiki Examples:

Examples:: SphinxExamples/src/Filtering/BinaryMathematicalMorphology/DilateABinaryImage/Code.cxx, SphinxExamples/src/Filtering/BinaryMathematicalMorphology/ErodeABinaryImage/Code.cxx, SphinxExamples/src/Filtering/LabelMap/ApplyMorphologicalClosingOnAllLabelObjects/Code.cxx, SphinxExamples/src/Filtering/LabelMap/ApplyMorphologicalClosingOnSpecificLabelObject/Code.cxx, SphinxExamples/src/Filtering/MathematicalMorphology/DilateAGrayscaleImage/Code.cxx, SphinxExamples/src/Filtering/MathematicalMorphology/ErodeAGrayscaleImage/Code.cxx, WikiExamples/Morphology/FlatStructuringElement.cxx, and WikiExamples/Morphology/FlatStructuringElementRadiusIsParametric.cxx.

Definition at line 26 of file itkKernelImageFilter.h.

Classes
struct	StructuringElementFacet

Public Types
using	ConstIterator = typename Superclass::ConstIterator

using	DecompType = std::vector< LType >

using	ImageType = typename itk::Image< PixelType, VDimension >

using	Iterator = typename Superclass::Iterator

using	LType = Vector< float, VDimension >

using	OffsetType = typename Superclass::OffsetType

using	PixelType = typename Superclass::PixelType

using	RadiusType = typename Superclass::RadiusType

using	Self = FlatStructuringElement< VDimension >

using	SizeType = typename Superclass::SizeType

using	SliceIteratorType = typename Superclass::SliceIteratorType

using	Superclass = Neighborhood< bool, VDimension >

Public Types inherited from itk::Neighborhood< bool, VDimension >
using	AllocatorType = NeighborhoodAllocator< bool >

using	ConstIterator = typename AllocatorType::const_iterator

using	DimensionValueType = unsigned int

using	Iterator = typename AllocatorType::iterator

using	NeighborIndexType = SizeValueType

using	OffsetType = Offset< VDimension >

using	PixelType = bool

using	RadiusType = ::itk::Size< VDimension >

using	Self = Neighborhood

using	SizeType = ::itk::Size< VDimension >

using	SizeValueType = typename SizeType::SizeValueType

using	SliceIteratorType = SliceIterator< bool, Self >

Public Member Functions
bool	CheckParallel (LType NewVec) const

void	ComputeBufferFromLines ()

	FlatStructuringElement ()

	~FlatStructuringElement () override=default


bool	GetDecomposable () const

void	SetDecomposable (bool v)


const DecompType &	GetLines () const

void	AddLine (LType l)


bool	GetRadiusIsParametric () const

void	SetRadiusIsParametric (bool flag)

virtual void	RadiusIsParametricOn ()

virtual void	RadiusIsParametricOff ()

Public Member Functions inherited from itk::Neighborhood< bool, VDimension >
NeighborIndexType	GetCenterNeighborhoodIndex () const

bool	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

	itkTypeMacroNoParent (Neighborhood)

	Neighborhood (const Self &other)

	Neighborhood (Self &&)=default

bool	operator!= (const Self &other) const

Self &	operator= (const Self &other)

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

	Neighborhood ()

Iterator	End ()

ConstIterator	End () const

Iterator	Begin ()

ConstIterator	Begin () const

bool &	operator[] (NeighborIndexType i)

const bool &	operator[] (NeighborIndexType i) const

bool &	GetElement (NeighborIndexType i)

bool &	operator[] (const OffsetType &o)

const bool &	operator[] (const OffsetType &o) const

void	SetRadius (const SizeValueType *rad)

AllocatorType &	GetBufferReference ()

const AllocatorType &	GetBufferReference () const

Static Public Member Functions
static Self	Annulus (RadiusType radius, unsigned int thickness=1, bool includeCenter=false, bool radiusIsParametric=false)

static Self	Ball (RadiusType radius, bool radiusIsParametric=false)

static Self	Box (RadiusType radius)

static Self	Cross (RadiusType radius)

static Self	FromImage (const ImageType *image)

static Self	Polygon (RadiusType radius, unsigned lines)

Static Public Attributes
static constexpr unsigned int	NeighborhoodDimension = VDimension

Static Public Attributes inherited from itk::Neighborhood< bool, VDimension >
static constexpr unsigned int	NeighborhoodDimension

Protected Member Functions
void	PrintSelf (std::ostream &os, Indent indent) const override

Protected Member Functions inherited from itk::Neighborhood< bool, VDimension >
virtual void	Allocate (NeighborIndexType i)

virtual void	ComputeNeighborhoodOffsetTable ()

virtual void	ComputeNeighborhoodStrideTable ()

void	SetSize ()

Private Types
using	FacetType = StructuringElementFacet< VDimension >

using	FacetType3 = StructuringElementFacet< 3 >

using	LType2 = Vector< float, 2 >

using	LType3 = Vector< float, 3 >

Static Private Member Functions
static RadiusType	CheckImageSize (const ImageType *image)

template<typename TStructuringElement , typename TRadius >
static void	GeneratePolygon (TStructuringElement &res, TRadius radius, unsigned lines)

static void	GeneratePolygon (itk::FlatStructuringElement< 2 > &res, itk::Size< 2 > radius, unsigned lines)

static void	GeneratePolygon (itk::FlatStructuringElement< 3 > &res, itk::Size< 3 > radius, unsigned lines)

Private Attributes
bool	m_Decomposable

DecompType	m_Lines

bool	m_RadiusIsParametric