#include <itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h>

Detailed Description

template<typename TImage>
class itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >

A multi-dimensional iterator templated over image type that walks pixels within a region and is specialized to keep track of its image index location.

This class is a specialization of ImageRegionConstIteratorWithIndex, adding method GetFrequencyBins to give the frequency bins corresponding to image indices, and GetFrequency to get the frequency of the bin. The frequency bins depends on the image size. The default assumes that the image to iterate over is the output of a forward FFT filter, where the first index corresponds to 0 frequency, and Nyquist Frequencies are in the middle, between positive and negative frequencies.

This class can be specialized further to iterate over other frequency layouts, for example shifted images (where 0 frequency is in the middle of the image, and Nyquist are in the border). For different layout, use other frequency iterator.

This iterator is for the frequency layout that results from applying a FFT (vnl or fftw) to an image. The default ImageInformation is: Origin = {{0}}, Spacing = {{1}}. In this case the frequency values will be in the range: [-1/2, 1/2] Hz Or [-pi, pi] rad/s To modify those ranges: a) Avoid modifying the origin. The origin index always corresponds to zero frequency after a FFT. The range should be always centered around zero. b) The spacing control the range of frequencies (always around zero). If the spacing is = {{0.5}} we get a frequency range of [-1/4, 1/4] or [-pi/2, pi/2].

The frequency layout is assumed to be: where fs is frequency sampling, or frequency spacing (1.0 by default). If N is even: Nyquist frequency at index=N/2 is shared between + and - regions. <---------—positive f ------------—><---------—negative f-----------—> 0(DC) fs/N 2*fs/N ... (N/2 -1)*fs/N fs/2 -(N/2-1)*fs/N ... -2*fs/N -fs/N

Example: Size 6:

+ | -

0 <– DC Component (0 freq) 1 | 5 2 | 4 3 <– Shared between regions, unique Nyquist.

If N is odd: Nyquist frequency is not represented but there are symmetric largest frequencies at index=N/2, N/2 +1 <-------—positive f ------------—><---------—negative f--------------—> 0(DC) fs/N 2*fs/N ...... fs/2*(N-1)/N -fs/2*(N-1)/N ... -2*fs/N -fs/N

Example: Size 5:

+ | -

0 <– DC Component (0 freq) 1 | 4 2 | 3 <– Absolute Largest Frequency bins (+, -)

Please see ImageRegionConstIteratorWithIndex for more information.

See also: ForwardFFTImageFilter

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: ImageRegionIteratorWithIndex; 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

Definition at line 115 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

Inheritance diagram for itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >:

Collaboration diagram for itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >:

Public Types
using	AccessorType = typename TImage::AccessorType

using	FrequencyType = typename ImageType::SpacingType

using	FrequencyValueType = typename ImageType::SpacingValueType

using	ImageType = TImage

using	IndexType = typename TImage::IndexType

using	InternalPixelType = typename TImage::InternalPixelType

using	OffsetType = typename TImage::OffsetType

using	PixelContainer = typename TImage::PixelContainer

using	PixelContainerPointer = typename PixelContainer::Pointer

using	PixelType = typename TImage::PixelType

using	RegionType = typename TImage::RegionType

using	Self = FrequencyFFTLayoutImageRegionConstIteratorWithIndex

using	SizeType = typename TImage::SizeType

using	Superclass = ImageRegionConstIteratorWithIndex< TImage >

Public Types inherited from itk::ImageRegionConstIteratorWithIndex< TImage >
using	AccessorType = typename TImage::AccessorType

using	ImageType = TImage

using	IndexType = typename TImage::IndexType

using	InternalPixelType = typename TImage::InternalPixelType

using	OffsetType = typename TImage::OffsetType

using	PixelContainer = typename TImage::PixelContainer

using	PixelContainerPointer = typename PixelContainer::Pointer

using	PixelType = typename TImage::PixelType

using	RegionType = typename TImage::RegionType

using	Self = ImageRegionConstIteratorWithIndex

using	SizeType = typename TImage::SizeType

using	Superclass = ImageConstIteratorWithIndex< TImage >

Public Types inherited from itk::ImageConstIteratorWithIndex< TImage >
using	AccessorFunctorType = typename TImage::AccessorFunctorType

using	AccessorType = typename TImage::AccessorType

using	ImageType = TImage

using	IndexType = typename TImage::IndexType

using	IndexValueType = typename IndexType::IndexValueType

using	InternalPixelType = typename TImage::InternalPixelType

using	OffsetType = typename TImage::OffsetType

using	OffsetValueType = typename OffsetType::OffsetValueType

using	PixelContainer = typename TImage::PixelContainer

using	PixelContainerPointer = typename PixelContainer::Pointer

using	PixelType = typename TImage::PixelType

using	RegionType = typename TImage::RegionType

using	Self = ImageConstIteratorWithIndex

using	SizeType = typename TImage::SizeType

using	SizeValueType = typename SizeType::SizeValueType

Public Member Functions
	FrequencyFFTLayoutImageRegionConstIteratorWithIndex ()

	FrequencyFFTLayoutImageRegionConstIteratorWithIndex (const Superclass &it)

	FrequencyFFTLayoutImageRegionConstIteratorWithIndex (const TImage *ptr, const RegionType &region)

IndexType	GetFrequencyBin () const

FrequencyValueType	GetFrequencyModuloSquare () const

virtual const FrequencyType &	GetFrequencyOrigin () const

virtual const FrequencyType &	GetFrequencySpacing () const

virtual const IndexType &	GetLargestPositiveFrequencyIndex () const

virtual const IndexType &	GetMaxIndex () const

virtual const IndexType &	GetMinIndex () const


FrequencyType	GetFrequency () const


void	SetActualXDimensionIsOdd (bool value)

virtual bool	GetActualXDimensionIsOdd ()

virtual void	ActualXDimensionIsOddOn ()

Public Member Functions inherited from itk::ImageRegionConstIteratorWithIndex< TImage >
	ImageRegionConstIteratorWithIndex ()

	ImageRegionConstIteratorWithIndex (const ImageConstIteratorWithIndex< TImage > &it)

	ImageRegionConstIteratorWithIndex (const TImage *ptr, const RegionType &region)

Self &	operator++ ()

Self &	operator-- ()

Public Member Functions inherited from itk::ImageConstIteratorWithIndex< TImage >
PixelType	Get () const

const IndexType &	GetIndex () const

const RegionType &	GetRegion () const

void	GoToBegin ()

void	GoToReverseBegin ()

	ImageConstIteratorWithIndex ()=default

	ImageConstIteratorWithIndex (const Self &it)

	ImageConstIteratorWithIndex (const TImage *ptr, const RegionType &region)

bool	IsAtEnd () const

bool	IsAtReverseEnd () const

	ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION (Self)

bool	operator< (const Self &it) const

bool	operator<= (const Self &it) const

Self &	operator= (const Self &it)

bool	operator== (const Self &it) const

bool	operator> (const Self &it) const

bool	operator>= (const Self &it) const

bool	Remaining ()

const PixelType &	Value () const

virtual	~ImageConstIteratorWithIndex ()=default

void	SetIndex (const IndexType &ind)

Private Member Functions

void	Init ()

Private Attributes
bool	m_ActualXDimensionIsOdd

FrequencyType	m_FrequencyOrigin

FrequencyType	m_FrequencySpacing

IndexType	m_LargestPositiveFrequencyIndex

IndexType	m_MaxIndex

IndexType	m_MinIndex

Additional Inherited Members
Static Public Member Functions inherited from itk::ImageConstIteratorWithIndex< TImage >
static constexpr unsigned int	GetImageDimension ()

Static Public Attributes inherited from itk::ImageConstIteratorWithIndex< TImage >
static constexpr unsigned int	ImageDimension = TImage::ImageDimension

Protected Attributes inherited from itk::ImageConstIteratorWithIndex< TImage >
const InternalPixelType *	m_Begin { nullptr }

IndexType	m_BeginIndex { { 0 } }

const InternalPixelType *	m_End { nullptr }

IndexType	m_EndIndex { { 0 } }

TImage::ConstWeakPointer	m_Image {}

OffsetValueType	m_OffsetTable [ImageDimension+1] {}

AccessorType	m_PixelAccessor {}

AccessorFunctorType	m_PixelAccessorFunctor {}

const InternalPixelType *	m_Position { nullptr }

IndexType	m_PositionIndex { { 0 } }

RegionType	m_Region {}

bool	m_Remaining { false }

Member Typedef Documentation

◆ AccessorType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::AccessorType = typename TImage::AccessorType

Accessor type that converts data between internal and external representations.

Definition at line 132 of file itkImageConstIteratorWithIndex.h.

◆ FrequencyType

template<typename TImage>

using itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyType = typename ImageType::SpacingType

Definition at line 136 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ FrequencyValueType

template<typename TImage>

using itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyValueType = typename ImageType::SpacingValueType

Definition at line 137 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ ImageType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::ImageType = TImage

Image type alias support

Definition at line 116 of file itkImageConstIteratorWithIndex.h.

◆ IndexType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::IndexType = typename TImage::IndexType

Index type alias support

Definition at line 105 of file itkImageConstIteratorWithIndex.h.

◆ InternalPixelType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::InternalPixelType = typename TImage::InternalPixelType

Internal Pixel Type

Definition at line 125 of file itkImageConstIteratorWithIndex.h.

◆ OffsetType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::OffsetType = typename TImage::OffsetType

Type of the Offset taken from the image

Definition at line 136 of file itkImageConstIteratorWithIndex.h.

◆ PixelContainer

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::PixelContainer = typename TImage::PixelContainer

PixelContainer type alias support Used to refer to the container for the pixel data. While this was already typedef'ed in the superclass, it needs to be redone here for this subclass to compile properly with gcc.

Definition at line 121 of file itkImageConstIteratorWithIndex.h.

◆ PixelContainerPointer

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::PixelContainerPointer = typename PixelContainer::Pointer

Definition at line 122 of file itkImageConstIteratorWithIndex.h.

◆ PixelType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::PixelType = typename TImage::PixelType

External Pixel Type

Definition at line 128 of file itkImageConstIteratorWithIndex.h.

◆ RegionType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::RegionType = typename TImage::RegionType

Region type alias support

Definition at line 113 of file itkImageConstIteratorWithIndex.h.

◆ Self

template<typename TImage>

using itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Self = FrequencyFFTLayoutImageRegionConstIteratorWithIndex

Standard class type alias.

Definition at line 121 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ SizeType

template<typename TImage>

using itk::ImageConstIteratorWithIndex< TImage >::SizeType = typename TImage::SizeType

Size type alias support

Definition at line 109 of file itkImageConstIteratorWithIndex.h.

◆ Superclass

template<typename TImage>

using itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Superclass = ImageRegionConstIteratorWithIndex<TImage>

Definition at line 122 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

Constructor & Destructor Documentation

◆ FrequencyFFTLayoutImageRegionConstIteratorWithIndex() [1/3]

template<typename TImage>

itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyFFTLayoutImageRegionConstIteratorWithIndex ( )

inline

Default constructor. Needed since we provide a cast constructor.

Definition at line 139 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ FrequencyFFTLayoutImageRegionConstIteratorWithIndex() [2/3]

template<typename TImage>

itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyFFTLayoutImageRegionConstIteratorWithIndex	(	const TImage *	ptr,
		const RegionType &	region
	)

inline

Constructor establishes an iterator to walk a particular image and a particular region of that image. Initializes the iterator at the begin of the region.

Definition at line 147 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ FrequencyFFTLayoutImageRegionConstIteratorWithIndex() [3/3]

template<typename TImage>

itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyFFTLayoutImageRegionConstIteratorWithIndex ( const Superclass & it )

inlineexplicit

Constructor that can be used to cast from an ImageIterator to an ImageRegionIteratorWithIndex. Many routines return an ImageIterator, but for a particular task, you may want an ImageRegionIteratorWithIndex. Rather than provide overloaded APIs that return different types of Iterators, itk returns ImageIterators and uses constructors to cast from an ImageIterator to a ImageRegionIteratorWithIndex.

Definition at line 159 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

Member Function Documentation

◆ ActualXDimensionIsOddOn()

template<typename TImage>

virtual void itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::ActualXDimensionIsOddOn ( )

virtual

Does nothing. This member only affects HalfHermitianFrequencyIterator. Provided for homogeneous interface between iterators.

◆ GetActualXDimensionIsOdd()

template<typename TImage>

virtual bool itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetActualXDimensionIsOdd ( )

virtual

Does nothing. This member only affects HalfHermitianFrequencyIterator. Provided for homogeneous interface between iterators.

◆ GetFrequency()

template<typename TImage>

FrequencyType itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequency ( ) const

inline

Note that this method is independent of the region in the constructor. It takes into account the ImageInformation of the Image in the frequency domain. This iterator is for the frequency layout that results from applying a FFT (vnl or fftw) to an image. If your image has a different layout, use other frequency iterator. The default ImageInformation is: Origin = {{0}}, Spacing = {{1}}. In this case the frequency values will be in the range: [-1/2, 1/2] Hz Or [-pi, pi] rad/s To modify those ranges: a) Avoid modifying the origin. The origin index always corresponds to zero frequency after a FFT. The range should be always centered around zero. b) The spacing control the range of frequencies (always around zero). If the spacing is = {{0.5}} we get a frequency range of [-1/4, 1/4] or [-pi/2, pi/2].

f = [0, 1, ..., N/2-1, -N/2, ..., -1] * FrequencySpacing if N is even f = [0, 1, ..., (N-1)/2, -(N-1)/2, ..., -1] * FrequencySpacing if N is odd

Where FrequencySpacing = samplingFrequency / N; and samplingFrequency = 1.0 / inputImageSpatialDomainSpacing;

Definition at line 208 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ GetFrequencyBin()

template<typename TImage>

IndexType itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyBin ( ) const

inline

Definition at line 171 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ GetFrequencyModuloSquare()

template<typename TImage>

FrequencyValueType itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyModuloSquare ( ) const

inline

Definition at line 222 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.

◆ GetFrequencyOrigin()

template<typename TImage>

virtual const FrequencyType& itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyOrigin ( ) const

virtual

Origin of frequencies is zero for FFT output.

◆ GetFrequencySpacing()

template<typename TImage>

virtual const FrequencyType& itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencySpacing ( ) const

virtual

This is the pixel width, or the bin size of the frequency in physical or world coordinates. SamplingFrequency = 1.0 / SpatialImageSpacing FrequencySpacing = SamplingFrequency / ImageSize FrequencySpacing = 1.0 / (SpatialImageSpacing * ImageSize) FrequencySpacing is computed at construction from the spacing of the input image, and cannot be modified.

◆ GetLargestPositiveFrequencyIndex()

template<typename TImage>

virtual const IndexType& itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetLargestPositiveFrequencyIndex ( ) const

virtual

Index corresponding to the first highest frequency (Nyquist) after a FFT transform. If the size of the image is even, the Nyquist frequency = fs/2 is unique and shared between positive and negative frequencies. (Even Size) LargestPositiveFrequencyIndex = originIndex + N / 2 If odd, Nyquist frequency is not represented, but there is still a largest frequency at this index = fs/2 * (N-1)/N. (Odd Size) LargestPositiveFrequencyIndex = originIndex + (N + 1) / 2

◆ GetMaxIndex()

template<typename TImage>

virtual const IndexType& itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetMaxIndex ( ) const

virtual

Default to UpperIndex of the largest possible Region.

◆ GetMinIndex()

template<typename TImage>

virtual const IndexType& itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetMinIndex ( ) const

virtual

Default to first index of the largest possible Region.

◆ Init()

template<typename TImage>

void itk::FrequencyFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init ( )

inlineprivate

Calculate Nyquist frequency index (m_LargestPositiveFrequencyIndex), Min/Max indices from LargestPossibleRegion. Also sets FrequencySpacing and FrequencyOrigin. Called by constructors.

Definition at line 278 of file itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex.h.