ITK  5.4.0
Insight Toolkit
Public Types | Public Member Functions | Private Attributes | List of all members
itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage > Class Template Reference

#include <itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h>

Detailed Description

template<typename TImage>
class itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< 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 is specialized to iterate over the frequency layout that result after applying a

See also
RealToHalfHermitianFFTForwardFFTImageFilter For different layouts, use other frequency iterator.
itkFrequencyFFTLayoutImageRegionConstIteratorWithIndex
itkFrequencyShiftedFFTLayoutImageRegionConstIteratorWithIndex

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: <---------— Frequencies ------------—> 0(DC) fs/N 2*fs/N ... (N/2 -1)*fs/N fs/2 <---------— Indices ----------------—> 0 1 2 ... (N/2-1) N/2

Example: Size 6:

0 <– DC Component (0 freq) 1 2 3 <– 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 ---------------—> 0(DC) fs/N ...... fs/2*(N-2)/N fs/2*(N-1)/N <---------— Indices ---------------—> 0 1 ...... (N-1)/2 -1 N/2(rounded down, i.e (N-1)/2)

Example: Size 5:

0 <– DC Component (0 freq) 1 2 <– Largest Frequency bins

Please see ImageRegionConstIteratorWithIndex for more information.

See also
RealToHalfHermitianFFTForwardFFTImageFilter
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 120 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h.

+ Inheritance diagram for itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >:
+ Collaboration diagram for itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< 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 = FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex
 
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

 FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex ()
 
 FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex (const Superclass &it)
 
 FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex (const TImage *ptr, const RegionType &region)
 
IndexType GetFrequencyBin () const
 
FrequencyValueType GetFrequencyModuloSquare () const
 
virtual const FrequencyTypeGetFrequencyOrigin () const
 
virtual const FrequencyTypeGetFrequencySpacing () const
 
virtual const IndexTypeGetLargestPositiveFrequencyIndex () const
 
virtual const IndexTypeGetMaxIndex () const
 
virtual const IndexTypeGetMinIndex () 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)
 
Selfoperator++ ()
 
Selfoperator-- ()
 
- Public Member Functions inherited from itk::ImageConstIteratorWithIndex< TImage >
PixelType Get () const
 
const IndexTypeGetIndex () const
 
const RegionTypeGetRegion () 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
 
Selfoperator= (const Self &it)
 
bool operator== (const Self &it) const
 
bool operator> (const Self &it) const
 
bool operator>= (const Self &it) const
 
bool Remaining ()
 
const PixelTypeValue () const
 
virtual ~ImageConstIteratorWithIndex ()=default
 
void SetIndex (const IndexType &ind)
 

Private Member Functions

void Init ()
 

Private Attributes

bool m_ActualXDimensionIsOdd { false }
 
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 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 InternalPixelTypem_Begin { nullptr }
 
IndexType m_BeginIndex { { 0 } }
 
const InternalPixelTypem_End { nullptr }
 
IndexType m_EndIndex { { 0 } }
 
TImage::ConstWeakPointer m_Image {}
 
OffsetValueType m_OffsetTable [ImageDimension+1] {}
 
AccessorType m_PixelAccessor {}
 
AccessorFunctorType m_PixelAccessorFunctor {}
 
const InternalPixelTypem_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::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyType = typename ImageType::SpacingType

◆ FrequencyValueType

template<typename TImage>
using itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::FrequencyValueType = typename ImageType::SpacingValueType

◆ 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

Standard class type alias.

Definition at line 126 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.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

Constructor & Destructor Documentation

◆ FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex() [1/3]

Default constructor. Needed since we provide a cast constructor.

Definition at line 144 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h.

References itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init().

◆ FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex() [2/3]

Constructor establishes an iterator to walk a particular image and a particular region of that image.

Definition at line 153 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h.

References itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init().

◆ FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex() [3/3]

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 165 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h.

References itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init().

Member Function Documentation

◆ ActualXDimensionIsOddOn()

template<typename TImage>
virtual void itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::ActualXDimensionIsOddOn ( )
virtual

In images resulting from itkRealToHalfHermitianForwardFFT the size in the fastest dimension (0) is n/2 + 1. To compute the right frequency spacing and the original size, this information has to be provided.

◆ GetActualXDimensionIsOdd()

template<typename TImage>
virtual bool itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetActualXDimensionIsOdd ( )
virtual

In images resulting from itkRealToHalfHermitianForwardFFT the size in the fastest dimension (0) is n/2 + 1. To compute the right frequency spacing and the original size, this information has to be provided.

Referenced by itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init(), and itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::SetActualXDimensionIsOdd().

◆ GetFrequency()

template<typename TImage>
FrequencyType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< 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 217 of file itkFrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex.h.

References itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyBin(), itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_FrequencyOrigin, and itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_FrequencySpacing.

Referenced by itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyModuloSquare().

◆ GetFrequencyBin()

template<typename TImage>
IndexType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyBin ( ) const
inline

◆ GetFrequencyModuloSquare()

template<typename TImage>
FrequencyValueType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyModuloSquare ( ) const
inline

◆ GetFrequencyOrigin()

template<typename TImage>
virtual const FrequencyType& itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetFrequencyOrigin ( ) const
virtual

Origin of frequencies is zero for FFT output.

◆ GetFrequencySpacing()

template<typename TImage>
virtual const FrequencyType& itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< 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::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< 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::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetMaxIndex ( ) const
virtual

Default to UpperIndex of the largest possible Region.

◆ GetMinIndex()

template<typename TImage>
virtual const IndexType& itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::GetMinIndex ( ) const
virtual

Default to first index of the largest possible Region.

◆ Init()

template<typename TImage>
void itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::Init ( )
inlineprivate

◆ SetActualXDimensionIsOdd()

template<typename TImage>
void itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::SetActualXDimensionIsOdd ( bool  value)
inline

Member Data Documentation

◆ m_ActualXDimensionIsOdd

template<typename TImage>
bool itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_ActualXDimensionIsOdd { false }
private

◆ m_FrequencyOrigin

template<typename TImage>
FrequencyType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_FrequencyOrigin
private

◆ m_FrequencySpacing

template<typename TImage>
FrequencyType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_FrequencySpacing
private

◆ m_LargestPositiveFrequencyIndex

template<typename TImage>
IndexType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_LargestPositiveFrequencyIndex
private

◆ m_MaxIndex

template<typename TImage>
IndexType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_MaxIndex
private

◆ m_MinIndex

template<typename TImage>
IndexType itk::FrequencyHalfHermitianFFTLayoutImageRegionConstIteratorWithIndex< TImage >::m_MinIndex
private

The documentation for this class was generated from the following file: