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ITK
5.4.0
Insight Toolkit
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ITK
5.4.0
Insight Toolkit
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#include <itkNeighborhoodIterator.h>
Defines iteration of a local N-dimensional neighborhood of pixels across an itk::Image.
This class is a loose extension of the Standard Template Library (STL) bi-directional iterator concept to masks of pixel neighborhoods within itk::Image objects. This NeighborhoodIterator base class defines simple forward and reverse iteration of an N-dimensional neighborhood mask across an image. Elements within the mask can be accessed like elements within an array.
NeighborhoodIterators are designed to encapsulate some of the complexity of working with image neighborhoods, complexity that would otherwise have to be managed at the algorithmic level. Use NeighborhoodIterators to simplify writing algorithms that perform geometrically localized operations on images (for example, convolution and morphological operations).
To motivate the discussion of NeighborhoodIterators and their use in Itk, consider the following code that takes directional derivatives at each point in an image.
Most of the work for the programmer in the code above is in setting up for the iteration. There are three steps. First an inner product function object is created which will be used to effect convolution with the derivative kernel. Setting up the derivative kernel, DerivativeOperator, involves setting the order and direction of the derivative. Finally, we create an iterator over the RequestedRegion of the itk::Image (see Image) using the radius of the derivative kernel as the size.
Itk iterators only loosely follow STL conventions. Notice that instead of asking myImage for myImage.begin() and myImage.end(), iterator.SetToBegin() and iterator.IsAtEnd() are called. Itk iterators are typically more complex objects than traditional, pointer-style STL iterators, and the increased overhead required to conform to the complete STL API is not always justified.
The API for creating and manipulating a NeighborhoodIterator mimics that of the itk::ImageIterators. Like the itk::ImageIterator, a ConstNeighborhoodIterator is defined on a region of interest in an itk::Image. Iteration is constrained within that region of interest.
A NeighborhoodIterator is constructed as a container of pointers (offsets) to a geometric neighborhood of image pixels. As the central pixel position in the mask is moved around the image, the neighboring pixel pointers (offsets) are moved accordingly.
A pixel neighborhood is defined as a central pixel location and an N-dimensional radius extending outward from that location.
Pixels in a neighborhood can be accessed through a NeighborhoodIterator like elements in an array. For example, a 2D neighborhood with radius 2x1 has indices:
Now suppose a NeighborhoodIterator with the above dimensions is constructed and positioned over a neighborhood of values in an Image:
Shown below is some sample pixel access code and the values that it returns.
Results:
Use of GetPixel() is preferred over the *iterator[] form, and can be used without loss of efficiency in most cases. Some variations (subclasses) of NeighborhoodIterators may exist which do not support the latter API. Corresponding SetPixel() methods exist to modify pixel values in non-const NeighborhoodIterators.
NeighborhoodIterators are "bidirectional iterators". They move only in two directions through the data set. These directions correspond to the layout of the image data in memory and not to spatial directions of the N-dimensional itk::Image. Iteration always proceeds along the fastest increasing dimension (as defined by the layout of the image data). For itk::Image this is the first dimension specified (i.e. for 3-dimensional (x,y,z) NeighborhoodIterator proceeds along the x-dimension) (For random access iteration through N-dimensional indices, use RandomAccessNeighborhoodIterator).
Each subclass of a ConstNeighborhoodIterator may also define its own mechanism for iteration through an image. In general, the Iterator does not directly keep track of its spatial location in the image, but uses a set of internal loop variables and offsets to trigger wraps at itk::Image region boundaries, and to identify the end of the itk::Image region.
Definition at line 212 of file itkNeighborhoodIterator.h.
Inheritance diagram for itk::NeighborhoodIterator< TImage, TBoundaryCondition >: Collaboration diagram for itk::NeighborhoodIterator< TImage, TBoundaryCondition >:Public Member Functions | |
| InternalPixelType * | GetCenterPointer () |
| NeighborhoodIterator () | |
| NeighborhoodIterator (const NeighborhoodIterator &n) | |
| NeighborhoodIterator (const SizeType &radius, ImageType *ptr, const RegionType ®ion) | |
| ITK_ITERATOR_VIRTUAL void | SetCenterPixel (const PixelType &p) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetNeighborhood (const NeighborhoodType &) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetNext (const unsigned int axis, const PixelType &v) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetNext (const unsigned int axis, const unsigned int i, const PixelType &v) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetPixel (const unsigned int i, const PixelType &v) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetPixel (const unsigned int i, const PixelType &v, bool &status) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetPrevious (const unsigned int axis, const unsigned int i, const PixelType &v) ITK_ITERATOR_FINAL |
| Self & | operator= (const Self &orig) |
| ITK_ITERATOR_VIRTUAL void | SetPixel (const OffsetType o, const PixelType &v) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | SetPrevious (const unsigned int axis, const PixelType &v) ITK_ITERATOR_FINAL |
| Public Member Functions inherited from itk::ConstNeighborhoodIterator< TImage, TBoundaryCondition > | |
| OffsetType | ComputeInternalIndex (const NeighborIndexType n) const |
| ConstNeighborhoodIterator ()=default | |
| ConstNeighborhoodIterator (const ConstNeighborhoodIterator &) | |
| IndexType | GetBeginIndex () const |
| IndexType | GetBound () const |
| IndexValueType | GetBound (NeighborIndexType n) const |
| ImageBoundaryConditionPointerType | GetBoundaryCondition () const |
| RegionType | GetBoundingBoxAsImageRegion () const |
| PixelType | GetCenterPixel () const |
| const InternalPixelType * | GetCenterPointer () const |
| IndexType | GetFastIndexPlusOffset (const OffsetType &o) const |
| const ImageType * | GetImagePointer () const |
| ITK_ITERATOR_VIRTUAL IndexType | GetIndex () const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL IndexType | GetIndex (const OffsetType &o) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL IndexType | GetIndex (NeighborIndexType i) const ITK_ITERATOR_FINAL |
| bool | GetNeedToUseBoundaryCondition () const |
| ITK_ITERATOR_VIRTUAL NeighborhoodType | GetNeighborhood () const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetNext (const unsigned int axis) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetNext (const unsigned int axis, NeighborIndexType i) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPixel (const NeighborIndexType i) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPixel (const OffsetType &o) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPixel (const OffsetType &o, bool &IsInBounds) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPixel (NeighborIndexType i, bool &IsInBounds) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPrevious (const unsigned int axis) const ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL PixelType | GetPrevious (const unsigned int axis, NeighborIndexType i) const ITK_ITERATOR_FINAL |
| RegionType | GetRegion () const |
| OffsetType | GetWrapOffset () const |
| OffsetValueType | GetWrapOffset (NeighborIndexType n) const |
| ITK_ITERATOR_VIRTUAL void | GoToBegin () ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL void | GoToEnd () ITK_ITERATOR_FINAL |
| bool | InBounds () const |
| bool | IndexInBounds (const NeighborIndexType n) const |
| bool | IndexInBounds (const NeighborIndexType n, OffsetType &internalIndex, OffsetType &offset) const |
| ITK_ITERATOR_VIRTUAL void | Initialize (const SizeType &radius, const ImageType *ptr, const RegionType ®ion) ITK_ITERATOR_FINAL |
| ITK_ITERATOR_VIRTUAL bool | IsAtBegin () const ITK_ITERATOR_FINAL |
| ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION (Self) | |
| void | NeedToUseBoundaryConditionOff () |
| void | NeedToUseBoundaryConditionOn () |
| Self & | operator++ () |
| Self & | operator+= (const OffsetType &) |
| OffsetType | operator- (const Self &b) const |
| Self & | operator-- () |
| Self & | operator-= (const OffsetType &) |
| bool | operator< (const Self &it) const |
| bool | operator<= (const Self &it) const |
| Self & | operator= (const Self &orig) |
| bool | operator== (const Self &it) const |
| bool | operator> (const Self &it) const |
| bool | operator>= (const Self &it) const |
| ITK_ITERATOR_VIRTUAL void | OverrideBoundaryCondition (const ImageBoundaryConditionPointerType i) ITK_ITERATOR_FINAL |
| void | PrintSelf (std::ostream &, Indent) const override |
| ITK_ITERATOR_VIRTUAL void | ResetBoundaryCondition () ITK_ITERATOR_FINAL |
| void | SetBoundaryCondition (const TBoundaryCondition &c) |
| void | SetNeedToUseBoundaryCondition (bool b) |
| ITK_ITERATOR_VIRTUAL void | SetRegion (const RegionType ®ion) ITK_ITERATOR_FINAL |
| ~ConstNeighborhoodIterator () override=default | |
| ConstNeighborhoodIterator (const SizeType &radius, const ImageType *ptr, const RegionType ®ion) | |
| ITK_ITERATOR_VIRTUAL bool | IsAtEnd () const ITK_ITERATOR_FINAL |
| void | SetLocation (const IndexType &position) |
| Public Member Functions inherited from itk::Neighborhood< TImage::InternalPixelType *, TImage::ImageDimension > | |
| NeighborIndexType | GetCenterNeighborhoodIndex () const |
| TImage::InternalPixelType * | GetCenterValue () const |
| virtual const char * | GetNameOfClass () 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) |
| NeighborIndexType | Size () const |
| virtual | ~Neighborhood ()=default |
| Iterator | End () |
| ConstIterator | End () const |
| Iterator | Begin () |
| ConstIterator | Begin () const |
| TImage::InternalPixelType * & | operator[] (NeighborIndexType i) |
| const TImage::InternalPixelType * & | operator[] (NeighborIndexType i) const |
| TImage::InternalPixelType * & | GetElement (NeighborIndexType i) |
| TImage::InternalPixelType * & | operator[] (const OffsetType &o) |
| const TImage::InternalPixelType * & | operator[] (const OffsetType &o) const |
| void | SetRadius (const SizeValueType *rad) |
| AllocatorType & | GetBufferReference () |
| const AllocatorType & | GetBufferReference () const |
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::ConstIterator = typename AllocatorType::const_iterator |
Definition at line 76 of file itkNeighborhood.h.
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::Iterator = typename AllocatorType::iterator |
Iterator type alias support Note the naming is intentional, i.e., AllocatorType::iterator and AllocatorType::const_iterator, because the allocator may be a vnl object or other type, which uses this form.
Definition at line 75 of file itkNeighborhood.h.
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::OffsetType = Offset<VDimension> |
Offset type used to reference neighbor locations
Definition at line 86 of file itkNeighborhood.h.
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::PixelType = TPixel |
External support for pixel type.
Definition at line 70 of file itkNeighborhood.h.
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::RadiusType = itk::Size<VDimension> |
Radius type alias support
Definition at line 83 of file itkNeighborhood.h.
| using itk::NeighborhoodIterator< TImage, TBoundaryCondition >::Self = NeighborhoodIterator |
Standard class type aliases.
Definition at line 216 of file itkNeighborhoodIterator.h.
| using itk::Neighborhood< TPixel, VDimension, TAllocator >::SizeType = itk::Size<VDimension> |
Size and value type alias support
Definition at line 79 of file itkNeighborhood.h.
| using itk::NeighborhoodIterator< TImage, TBoundaryCondition >::Superclass = ConstNeighborhoodIterator<TImage, TBoundaryCondition> |
Definition at line 217 of file itkNeighborhoodIterator.h.
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Default constructor.
Definition at line 234 of file itkNeighborhoodIterator.h.
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Copy constructor
Definition at line 239 of file itkNeighborhoodIterator.h.
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Constructor which establishes the region size, neighborhood, and image over which to walk.
Definition at line 254 of file itkNeighborhoodIterator.h.
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Returns the central memory pointer of the neighborhood.
Definition at line 260 of file itkNeighborhoodIterator.h.
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Assignment operator
Definition at line 245 of file itkNeighborhoodIterator.h.
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Returns the central pixel of the neighborhood.
Definition at line 267 of file itkNeighborhoodIterator.h.
| ITK_ITERATOR_VIRTUAL void itk::NeighborhoodIterator< TImage, TBoundaryCondition >::SetNeighborhood | ( | const NeighborhoodType & | ) |
Virtual function that replaces the pixel values in the image neighborhood that are pointed to by this NeighborhoodIterator with the pixel values contained in a Neighborhood.
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Sets the pixel value located one pixel distant from the neighborhood center in the specified positive axis direction. No bounds checking is done on the size of the neighborhood.
Definition at line 311 of file itkNeighborhoodIterator.h.
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Sets the pixel value located i pixels distant from the neighborhood center in the positive specified "axis" direction. No bounds checking is done on the size of the neighborhood.
Definition at line 302 of file itkNeighborhoodIterator.h.
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Set the pixel at offset o from the neighborhood center
Definition at line 291 of file itkNeighborhoodIterator.h.
| ITK_ITERATOR_VIRTUAL void itk::NeighborhoodIterator< TImage, TBoundaryCondition >::SetPixel | ( | const unsigned int | i, |
| const PixelType & | v | ||
| ) |
Set the pixel at the ith location.
| ITK_ITERATOR_VIRTUAL void itk::NeighborhoodIterator< TImage, TBoundaryCondition >::SetPixel | ( | const unsigned int | i, |
| const PixelType & | v, | ||
| bool & | status | ||
| ) |
Special SetPixel method which quietly ignores out-of-bounds attempts. Sets status TRUE if pixel has been set, FALSE otherwise.
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Sets the pixel value located one pixel distant from the neighborhood center in the specified negative axis direction. No bounds checking is done on the size of the neighborhood.
Definition at line 329 of file itkNeighborhoodIterator.h.
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Sets the pixel value located i pixels distant from the neighborhood center in the negative specified "axis" direction. No bounds checking is done on the size of the neighborhood.
Definition at line 320 of file itkNeighborhoodIterator.h.
1.8.16