#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:

using ImageType = Image<float, 3>;
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.

using ImageType = Image<float, 3>;
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 https://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 153 of file itkShapedNeighborhoodIterator.h.

Classes
struct	Iterator

Public Types
using	BoundaryConditionType = typename Superclass::BoundaryConditionType

using	ConstIterator = typename Superclass::ConstIterator

using	ImageBoundaryConditionPointerType = typename Superclass::ImageBoundaryConditionPointerType

using	ImageType = typename Superclass::ImageType

using	IndexListType = typename Superclass::IndexListType

using	IndexType = typename Superclass::IndexType

using	IndexValueType = typename Superclass::IndexValueType

using	InternalPixelType = typename TImage::InternalPixelType

using	NeighborhoodType = typename Superclass::NeighborhoodType

using	OffsetType = typename Superclass::OffsetType

using	OffsetValueType = typename OffsetType::OffsetValueType

using	PixelType = typename TImage::PixelType

using	RadiusType = typename Superclass::RadiusType

using	RegionType = typename Superclass::RegionType

using	Self = ShapedNeighborhoodIterator

using	SizeType = typename Superclass::SizeType

using	SizeValueType = typename Superclass::SizeValueType

using	Superclass = ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >

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

using	ImageBoundaryConditionPointerType = ImageBoundaryCondition< ImageType > *

using	ImageType = TImage

using	IndexListConstIterator = typename IndexListType::const_iterator

using	IndexListIterator = typename IndexListType::iterator

using	IndexListType = std::list< NeighborIndexType >

using	IndexType = Index< Self::Dimension >

using	IndexValueType = typename IndexType::IndexValueType

using	InternalPixelType = typename TImage::InternalPixelType

using	NeighborhoodType = Neighborhood< PixelType, Self::Dimension >

using	NeighborIndexType = typename NeighborhoodType::NeighborIndexType

using	OffsetType = typename Superclass::OffsetType

using	OffsetValueType = typename OffsetType::OffsetValueType

using	PixelType = typename TImage::PixelType

using	RadiusType = typename Superclass::RadiusType

using	RegionType = typename TImage::RegionType

using	Self = ConstShapedNeighborhoodIterator

using	SizeType = typename Superclass::SizeType

using	SizeValueType = typename SizeType::SizeValueType

using	Superclass = NeighborhoodIterator< TImage, TBoundaryCondition >

Public Member Functions
void	PrintSelf (std::ostream &, Indent) const override

	ShapedNeighborhoodIterator ()=default

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

	~ShapedNeighborhoodIterator () override=default


Self &	operator= (const Self &orig)


Iterator	Begin ()

Iterator	End ()

Public Member Functions inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
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 &)

ConstIterator	Begin () const

ConstIterator	End () const

	ConstShapedNeighborhoodIterator ()=default

	~ConstShapedNeighborhoodIterator () override=default

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

Self &	operator= (const Self &orig)

ITK_ITERATOR_VIRTUAL void	ActivateOffset (const OffsetType &off) ITK_ITERATOR_FINAL

ITK_ITERATOR_VIRTUAL void	DeactivateOffset (const OffsetType &off) ITK_ITERATOR_FINAL

template<typename TOffsets >
void	ActivateOffsets (const TOffsets &offsets)

ITK_ITERATOR_VIRTUAL void	ClearActiveList () ITK_ITERATOR_FINAL

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

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

Protected Types
using	NeighborIndexType = typename Superclass::NeighborIndexType

Protected Member Functions
	ShapedNeighborhoodIterator (const ShapedNeighborhoodIterator &o)=delete

Protected Member Functions inherited from itk::ConstShapedNeighborhoodIterator< TImage, TBoundaryCondition >
ITK_ITERATOR_VIRTUAL void	ActivateIndex (NeighborIndexType) ITK_ITERATOR_FINAL

ITK_ITERATOR_VIRTUAL void	DeactivateIndex (NeighborIndexType) ITK_ITERATOR_FINAL

Protected Attributes
friend	Superclass

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

bool	m_CenterIsActive { false }