#include <itkShapedNeighborhoodIterator.h>

Inheritance diagram for itk::ShapedNeighborhoodIterator< TImage, TBoundaryCondition >:

Collaboration diagram for itk::ShapedNeighborhoodIterator< TImage, TBoundaryCondition >:

Detailed Description

template<typename TImage, typename TBoundaryCondition = ZeroFluxNeumannBoundaryCondition< TImage >>
class itk::ShapedNeighborhoodIterator< TImage, TBoundaryCondition >

A neighborhood iterator which can take on an arbitrary shape.

General Information: The ShapedNeighborhoodIterator is a refinement of NeighborhoodIterator which allows the user to specify which of the neighborhood elements are active and which will be ignored. This is useful for applications which only need to work with a subset of the neighborhood around a pixel such as morphological operations or cellular automata. This iterator can also be used, for example, to specify "cross-shaped" neighborhood where only elements along a spatial axes are significant.

Constructing a shaped neighborhood iterator: A shaped neighborhood iterator is constructed by constructing a list of active neighbor locations. The list is called the ActiveIndexList. The methods ActivateOffset, DeactivateOffset, and ClearActiveList are used to construct the ActiveIndexList. The argument to Activate/DeactivateOffset is an itk::Offset which represents the ND spatial offset from the center of the neighborhood. For example, to activate the center pixel in the neighborhood, you would do the following:

* typedef Image<float, 3> ImageType;
* ShapedNeighborhoodIterator<ImageType> it(radius, image, region);
* ShapedNeighborhoodIterator<ImageType>::OffsetType offset = {{0,0,0}};
* it.ActivateOffset(offset);
* 

where radius, image, and region are as described in NeighborhoodIterator.

Once a neighborhood location has been activated, iteration (operator++, operator--, operator+=, operator-=) will update the value at the active location. Note that values at inactive locations will NOT be valid if queried.

Accessing elements in a shaped neighborhood.: To access the value at an active neighborhood location, you can use the standard GetPixel, SetPixel methods. SetPixel is not defined for ConstShapedNeighborhoodIterator. The class will not complain if you attempt to access a value at a non-active location, but be aware that the result will be undefined. Error checking is not done in this case for the sake of efficiency.

A second way to access active shaped neighborhood values is through a ShapedNeighborhoodIterator::Iterator or ConstShapedNeighborhoodIterator::ConstIterator. The following example demonstrates the use of these iterators.

* typedef Image<float, 3> ImageType;
* ShapedNeighborhoodIterator<ImageType> it(radius, image, region);
* .
* .
* .
* it.ActivateOffset(offset1);
* it.ActivateOffset(offset2);
* it.ActivateOffset(offset3);
* etc..
* .
* .
* .
* ShapedNeighborhoodIterator<ImageType>::Iterator i;
* for (i = it.Begin(); ! i.IsAtEnd(); i++)
* { i.Set(i.Get() + 1.0); }
* \\ you may also use i != i.End(), but IsAtEnd() may be slightly faster.
* 

You can also iterate backward through the neighbohood active list.

* i = it.End();
* i--;
* while (i != it.Begin())
* {
*   i.Set(i.Get() + 1.0);
*   i--;
* }
*  i.Set(i.Get() + 1.0);
* 

The Get() Set() syntax was chosen versus defining operator* for these iterators because lvalue vs. rvalue context information is needed to determine whether bounds checking must take place.

See Also: Neighborhood

MORE INFORMATION: For a complete description of the ITK Image Iterators and their API, please see the Iterators chapter in the ITK Software Guide. The ITK Software Guide is available in print and as a free .pdf download from http://www.itk.org.

See Also: ImageConstIterator; ConditionalConstIterator; ConstNeighborhoodIterator; ConstShapedNeighborhoodIterator; ConstSliceIterator; CorrespondenceDataStructureIterator; FloodFilledFunctionConditionalConstIterator; FloodFilledImageFunctionConditionalConstIterator; FloodFilledImageFunctionConditionalIterator; FloodFilledSpatialFunctionConditionalConstIterator; FloodFilledSpatialFunctionConditionalIterator; ImageConstIterator; ImageConstIteratorWithIndex; ImageIterator; ImageIteratorWithIndex; ImageLinearConstIteratorWithIndex; ImageLinearIteratorWithIndex; ImageRandomConstIteratorWithIndex; ImageRandomIteratorWithIndex; ImageRegionConstIterator; ImageRegionConstIteratorWithIndex; ImageRegionExclusionConstIteratorWithIndex; ImageRegionExclusionIteratorWithIndex; ImageRegionIterator; ImageRegionIteratorWithIndex; ImageRegionReverseConstIterator; ImageRegionReverseIterator; ImageReverseConstIterator; ImageReverseIterator; ImageSliceConstIteratorWithIndex; ImageSliceIteratorWithIndex; NeighborhoodIterator; PathConstIterator; PathIterator; ShapedNeighborhoodIterator; SliceIterator; ImageConstIteratorWithIndex

Wiki Examples:

Definition at line 152 of file itkShapedNeighborhoodIterator.h.

Classes
struct	Iterator

Public Types
typedef Superclass::BoundaryConditionType	BoundaryConditionType

typedef Superclass::ConstIterator	ConstIterator

typedef Superclass::ImageBoundaryConditionPointerType	ImageBoundaryConditionPointerType

typedef Superclass::ImageType	ImageType

typedef Superclass::IndexListType	IndexListType

typedef Superclass::IndexType	IndexType

typedef Superclass::IndexValueType	IndexValueType

typedef TImage::InternalPixelType	InternalPixelType

typedef Superclass::NeighborhoodType	NeighborhoodType

typedef Superclass::OffsetType	OffsetType

typedef OffsetType::OffsetValueType	OffsetValueType

typedef TImage::PixelType	PixelType

typedef Superclass::RadiusType	RadiusType

typedef Superclass::RegionType	RegionType

typedef ShapedNeighborhoodIterator	Self

typedef Superclass::SizeType	SizeType

typedef Superclass::SizeValueType	SizeValueType

typedef ConstShapedNeighborhoodIterator < TImage, TBoundaryCondition >	Superclass

Public Types inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
typedef TBoundaryCondition	BoundaryConditionType

typedef ImageBoundaryCondition < ImageType > *	ImageBoundaryConditionPointerType

typedef IndexListType::const_iterator	IndexListConstIterator

typedef IndexListType::iterator	IndexListIterator

typedef std::list < NeighborIndexType >	IndexListType

typedef TImage::InternalPixelType	InternalPixelType

typedef NeighborhoodType::NeighborIndexType	NeighborIndexType

typedef Superclass::OffsetType	OffsetType

typedef OffsetType::OffsetValueType	OffsetValueType

typedef TImage::PixelType	PixelType

typedef Superclass::RadiusType	RadiusType

typedef ConstShapedNeighborhoodIterator	Self

typedef Superclass::SizeType	SizeType

typedef SizeType::SizeValueType	SizeValueType

typedef NeighborhoodIterator < TImage, TBoundaryCondition >	Superclass

typedef TImage	ImageType

typedef TImage::RegionType	RegionType

typedef Index < itkGetStaticConstMacro(Dimension) >	IndexType

typedef IndexType::IndexValueType	IndexValueType

typedef Neighborhood < PixelType, itkGetStaticConstMacro(Dimension) >	NeighborhoodType

Public Member Functions
void	ClearActiveList ()

const ConstIterator &	End () const

Self &	operator= (const Self &orig)

virtual void	PrintSelf (std::ostream &, Indent) const

virtual	~ShapedNeighborhoodIterator ()


	ShapedNeighborhoodIterator ()


	ShapedNeighborhoodIterator (const SizeType &radius, const ImageType *ptr, const RegionType &region)


Iterator &	Begin ()

Iterator &	End ()

Public Member Functions inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
	ConstShapedNeighborhoodIterator (const SizeType &radius, const ImageType *ptr, const RegionType &region)

void	CreateActiveListFromNeighborhood (const NeighborhoodType &)

const IndexListType &	GetActiveIndexList () const

IndexListType::size_type	GetActiveIndexListSize () const

Self &	operator++ ()

Self &	operator+= (const OffsetType &)

Self &	operator-- ()

Self &	operator-= (const OffsetType &)

virtual	~ConstShapedNeighborhoodIterator ()

const ConstIterator &	Begin () const

const ConstIterator &	End () const

	ConstShapedNeighborhoodIterator ()

void	InitializeConstShapedNeighborhoodIterator ()

Self &	operator= (const Self &orig)

virtual void	ActivateOffset (const OffsetType &off)

virtual void	DeactivateOffset (const OffsetType &off)

Static Public Attributes
static const unsigned int	Dimension = TImage::ImageDimension

Static Public Attributes inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
static const unsigned int	Dimension = TImage::ImageDimension

Protected Types
typedef Superclass::NeighborIndexType	NeighborIndexType

Protected Member Functions
void	ActivateIndex (NeighborIndexType n)

void	DeactivateIndex (NeighborIndexType n)

	ShapedNeighborhoodIterator (const ShapedNeighborhoodIterator &o)

Protected Member Functions inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
	ConstShapedNeighborhoodIterator (const ConstShapedNeighborhoodIterator &)

Protected Attributes
Iterator	m_BeginIterator

Iterator	m_EndIterator

Protected Attributes inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
IndexListType	m_ActiveIndexList

bool	m_CenterIsActive

ConstIterator	m_ConstBeginIterator

ConstIterator	m_ConstEndIterator