#include <itkVectorGradientMagnitudeImageFilter.h>

Inheritance diagram for itk::VectorGradientMagnitudeImageFilter< TInputImage, TRealType, TOutputImage >:

Collaboration diagram for itk::VectorGradientMagnitudeImageFilter< TInputImage, TRealType, TOutputImage >:

Public Types
typedef ConstNeighborhoodIterator < RealVectorImageType >	ConstNeighborhoodIteratorType
typedef SmartPointer< const Self >	ConstPointer
typedef InputImageType::Pointer	InputImagePointer
typedef TInputImage	InputImageType
typedef TInputImage::PixelType	InputPixelType
typedef OutputImageType::Pointer	OutputImagePointer
typedef Superclass::OutputImageRegionType	OutputImageRegionType
typedef TOutputImage	OutputImageType
typedef TOutputImage::PixelType	OutputPixelType
typedef SmartPointer< Self >	Pointer
typedef ConstNeighborhoodIteratorType::RadiusType	RadiusType
typedef TRealType	RealType
typedef Image< RealVectorType,::itk::GetImageDimension < TInputImage > ::ImageDimension >	RealVectorImageType
typedef Vector< TRealType,::itk::GetVectorDimension < InputPixelType > ::VectorDimension >	RealVectorType
typedef VectorGradientMagnitudeImageFilter	Self
typedef ImageToImageFilter < TInputImage, TOutputImage >	Superclass
typedef FixedArray< TRealType, VectorDimension >	WeightsType
Public Types inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
typedef InputImageType::ConstPointer	InputImageConstPointer
typedef InputImageType::PixelType	InputImagePixelType
typedef InputImageType::RegionType	InputImageRegionType
typedef Superclass::OutputImagePixelType	OutputImagePixelType
Public Types inherited from itk::ImageSource< TOutputImage >
typedef Superclass::DataObjectIdentifierType	DataObjectIdentifierType
typedef DataObject::Pointer	DataObjectPointer
typedef Superclass::DataObjectPointerArraySizeType	DataObjectPointerArraySizeType
Public Types inherited from itk::ProcessObject
typedef std::vector < DataObjectPointer >	DataObjectPointerArray
typedef std::vector < DataObjectIdentifierType >	NameArray
Public Types inherited from itk::Object
Public Types inherited from itk::LightObject

Public Member Functions
virtual ::itk::LightObject::Pointer	CreateAnother (void) const
virtual void	GenerateInputRequestedRegion () throw ( InvalidRequestedRegionError )
virtual const char *	GetNameOfClass () const
virtual bool	GetUseImageSpacing () const
void	SetUseImageSpacing (bool)
void	SetUseImageSpacingOff ()
void	SetUseImageSpacingOn ()
void	SetUsePrincipleComponentsOff ()
	typedef (Concept::HasNumericTraits< typename InputPixelType::ValueType >) InputHasNumericTraitsCheck
	typedef (Concept::HasNumericTraits< RealType >) RealTypeHasNumericTraitsCheck

virtual void	SetDerivativeWeights (WeightsType _arg)
virtual const WeightsType &	GetDerivativeWeights ()

virtual void	SetComponentWeights (WeightsType _arg)
virtual const WeightsType &	GetComponentWeights ()

virtual const RadiusType &	GetNeighborhoodRadius ()
virtual void	SetNeighborhoodRadius (RadiusType _arg)

virtual void	SetUsePrincipleComponents (bool _arg)
virtual bool	GetUsePrincipleComponents () const
void	SetUsePrincipleComponentsOn ()
Public Member Functions inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
const InputImageType *	GetInput (void) const
const InputImageType *	GetInput (unsigned int idx) const
virtual void	PopBackInput ()
virtual void	PopFrontInput ()
virtual void	PushBackInput (const InputImageType *image)
virtual void	PushFrontInput (const InputImageType *image)
virtual void	SetInput (const InputImageType *image)
virtual void	SetInput (unsigned int, const TInputImage *image)
Public Member Functions inherited from itk::ImageSource< TOutputImage >
OutputImageType *	GetOutput (unsigned int idx)
virtual void	GraftNthOutput (unsigned int idx, DataObject *output)
virtual void	GraftOutput (DataObject *output)
virtual void	GraftOutput (const DataObjectIdentifierType &key, DataObject *output)
OutputImageType *	GetOutput (void)
const OutputImageType *	GetOutput (void) const
virtual ProcessObject::DataObjectPointer	MakeOutput (ProcessObject::DataObjectPointerArraySizeType idx)
Public Member Functions inherited from itk::ProcessObject
virtual void	AbortGenerateDataOff ()
virtual void	AbortGenerateDataOn ()
virtual void	EnlargeOutputRequestedRegion (DataObject *)
virtual const bool &	GetAbortGenerateData ()
NameArray	GetInputNames () const
MultiThreader *	GetMultiThreader () const
DataObjectPointerArraySizeType	GetNumberOfIndexedInputs () const
DataObjectPointerArraySizeType	GetNumberOfInputs () const
DataObjectPointerArraySizeType	GetNumberOfOutputs () const
virtual DataObjectPointerArraySizeType	GetNumberOfValidRequiredInputs () const
NameArray	GetOutputNames () const
virtual const float &	GetProgress ()
NameArray	GetRequiredInputNames () const
bool	HasInput (const DataObjectIdentifierType &key) const
bool	HasOutput (const DataObjectIdentifierType &key) const
virtual DataObjectPointer	MakeOutput (const DataObjectIdentifierType &)
virtual void	PrepareOutputs ()
virtual void	PropagateRequestedRegion (DataObject *output)
virtual void	ResetPipeline ()
virtual void	SetAbortGenerateData (bool _arg)
virtual void	SetProgress (float _arg)
virtual void	Update ()
virtual void	UpdateLargestPossibleRegion ()
virtual void	UpdateOutputData (DataObject *output)
virtual void	UpdateOutputInformation ()
void	UpdateProgress (float amount)
DataObjectPointerArray	GetInputs ()
DataObjectPointerArray	GetOutputs ()
DataObjectPointerArray	GetIndexedInputs ()
DataObjectPointerArray	GetIndexedOutputs ()
DataObjectPointerArraySizeType	GetNumberOfIndexedOutputs () const
virtual void	SetReleaseDataFlag (bool flag)
virtual bool	GetReleaseDataFlag () const
void	ReleaseDataFlagOn ()
void	ReleaseDataFlagOff ()
virtual void	SetReleaseDataBeforeUpdateFlag (bool _arg)
virtual const bool &	GetReleaseDataBeforeUpdateFlag ()
virtual void	ReleaseDataBeforeUpdateFlagOn ()
virtual void	ReleaseDataBeforeUpdateFlagOff ()
virtual void	SetNumberOfThreads (ThreadIdType _arg)
virtual const ThreadIdType &	GetNumberOfThreads ()
Public Member Functions inherited from itk::Object
unsigned long	AddObserver (const EventObject &event, Command *)
unsigned long	AddObserver (const EventObject &event, Command *) const
virtual void	DebugOff () const
virtual void	DebugOn () const
Command *	GetCommand (unsigned long tag)
bool	GetDebug () const
MetaDataDictionary &	GetMetaDataDictionary (void)
const MetaDataDictionary &	GetMetaDataDictionary (void) const
virtual unsigned long	GetMTime () const
virtual const TimeStamp &	GetTimeStamp () const
bool	HasObserver (const EventObject &event) const
void	InvokeEvent (const EventObject &)
void	InvokeEvent (const EventObject &) const
virtual void	Modified () const
virtual void	Register () const
void	RemoveAllObservers ()
void	RemoveObserver (unsigned long tag)
void	SetDebug (bool debugFlag) const
void	SetMetaDataDictionary (const MetaDataDictionary &rhs)
virtual void	SetReferenceCount (int)
virtual void	UnRegister () const
Public Member Functions inherited from itk::LightObject
virtual void	Delete ()
virtual int	GetReferenceCount () const
	itkCloneMacro (Self)
void	Print (std::ostream &os, Indent indent=0) const

Static Public Member Functions
static int	CubicSolver (double , double )
static Pointer	New ()

Static Public Attributes
static const unsigned int	ImageDimension = TOutputImage::ImageDimension
static const unsigned int	VectorDimension = InputPixelType::Dimension
Static Public Attributes inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
static const unsigned int	InputImageDimension = TInputImage::ImageDimension
static const unsigned int	OutputImageDimension = TOutputImage::ImageDimension
Static Public Attributes inherited from itk::ImageSource< TOutputImage >

Protected Types
typedef InputImageType::Superclass	ImageBaseType
Protected Types inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
typedef ImageToImageFilterDetail::ImageRegionCopier < itkGetStaticConstMacro(OutputImageDimension), itkGetStaticConstMacro(InputImageDimension) >	InputToOutputRegionCopierType
typedef ImageToImageFilterDetail::ImageRegionCopier < itkGetStaticConstMacro(InputImageDimension), itkGetStaticConstMacro(OutputImageDimension) >	OutputToInputRegionCopierType

Protected Member Functions
void	BeforeThreadedGenerateData ()
TRealType	EvaluateAtNeighborhood (const ConstNeighborhoodIteratorType &it) const
TRealType	EvaluateAtNeighborhood3D (const ConstNeighborhoodIteratorType &it) const
virtual const ImageBaseType *	GetRealValuedInputImage ()
TRealType	NonPCEvaluateAtNeighborhood (const ConstNeighborhoodIteratorType &it) const
void	PrintSelf (std::ostream &os, Indent indent) const
void	ThreadedGenerateData (const OutputImageRegionType &outputRegionForThread, ThreadIdType threadId)
	VectorGradientMagnitudeImageFilter ()
virtual	~VectorGradientMagnitudeImageFilter ()
Protected Member Functions inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
virtual void	CallCopyInputRegionToOutputRegion (OutputImageRegionType &destRegion, const InputImageRegionType &srcRegion)
virtual void	CallCopyOutputRegionToInputRegion (InputImageRegionType &destRegion, const OutputImageRegionType &srcRegion)
	ImageToImageFilter ()
virtual void	VerifyInputInformation ()
	~ImageToImageFilter ()
void	PushBackInput (const DataObject *input)
void	PushFrontInput (const DataObject *input)
Protected Member Functions inherited from itk::ImageSource< TOutputImage >
virtual void	AfterThreadedGenerateData ()
virtual void	AllocateOutputs ()
virtual void	GenerateData ()
	ImageSource ()
virtual unsigned int	SplitRequestedRegion (unsigned int i, unsigned int num, OutputImageRegionType &splitRegion)
virtual	~ImageSource ()
Protected Member Functions inherited from itk::ProcessObject
virtual void	AddInput (DataObject *input)
virtual void	AddOutput (DataObject *output)
bool	AddRequiredInputName (const DataObjectIdentifierType &)
virtual void	CacheInputReleaseDataFlags ()
virtual void	GenerateOutputInformation ()
virtual void	GenerateOutputRequestedRegion (DataObject *output)
virtual const DataObjectPointerArraySizeType &	GetNumberOfRequiredInputs ()
virtual const DataObjectPointerArraySizeType &	GetNumberOfRequiredOutputs ()
bool	IsIndexedName (const DataObjectIdentifierType &) const
bool	IsRequiredInputName (const DataObjectIdentifierType &) const
	itkLegacyMacro (virtual void RemoveInput(DataObject *input))
	itkLegacyMacro (virtual void RemoveOutput(DataObject *output))
	itkLegacyMacro (void SetNumberOfInputs(DataObjectPointerArraySizeType num))
	itkLegacyMacro (void SetNumberOfOutputs(DataObjectPointerArraySizeType num))
DataObjectPointerArraySizeType	MakeIndexFromName (const DataObjectIdentifierType &) const
DataObjectIdentifierType	MakeNameFromIndex (DataObjectPointerArraySizeType) const
	ProcessObject ()
virtual void	PropagateResetPipeline ()
virtual void	ReleaseInputs ()
virtual void	RemoveInput (const DataObjectIdentifierType &key)
virtual void	RemoveInput (DataObjectPointerArraySizeType)
virtual void	RemoveOutput (const DataObjectIdentifierType &key)
virtual void	RemoveOutput (DataObjectPointerArraySizeType idx)
bool	RemoveRequiredInputName (const DataObjectIdentifierType &)
virtual void	RestoreInputReleaseDataFlags ()
virtual void	SetInput (const DataObjectIdentifierType &key, DataObject *input)
virtual void	SetNthInput (DataObjectPointerArraySizeType num, DataObject *input)
virtual void	SetNthOutput (DataObjectPointerArraySizeType num, DataObject *output)
void	SetNumberOfIndexedInputs (DataObjectPointerArraySizeType num)
void	SetNumberOfIndexedOutputs (DataObjectPointerArraySizeType num)
virtual void	SetNumberOfRequiredInputs (DataObjectPointerArraySizeType)
virtual void	SetNumberOfRequiredOutputs (DataObjectPointerArraySizeType _arg)
virtual void	SetOutput (const DataObjectIdentifierType &key, DataObject *output)
virtual void	SetPrimaryInput (DataObject *input)
virtual void	SetPrimaryOutput (DataObject *output)
void	SetRequiredInputNames (const NameArray &)
virtual void	VerifyPreconditions ()
	~ProcessObject ()
DataObject *	GetInput (const DataObjectIdentifierType &key)
const DataObject *	GetInput (const DataObjectIdentifierType &key) const
DataObject *	GetInput (DataObjectPointerArraySizeType)
const DataObject *	GetInput (DataObjectPointerArraySizeType idx) const
DataObject *	GetPrimaryInput ()
const DataObject *	GetPrimaryInput () const
DataObject *	GetOutput (const DataObjectIdentifierType &key)
const DataObject *	GetOutput (const DataObjectIdentifierType &key) const
DataObject *	GetOutput (DataObjectPointerArraySizeType idx)
const DataObject *	GetOutput (DataObjectPointerArraySizeType idx) const
DataObject *	GetPrimaryOutput ()
const DataObject *	GetPrimaryOutput () const
Protected Member Functions inherited from itk::Object
	Object ()
bool	PrintObservers (std::ostream &os, Indent indent) const
virtual void	SetTimeStamp (const TimeStamp &time)
virtual	~Object ()
Protected Member Functions inherited from itk::LightObject
virtual LightObject::Pointer	InternalClone () const
	LightObject ()
virtual void	PrintHeader (std::ostream &os, Indent indent) const
virtual void	PrintTrailer (std::ostream &os, Indent indent) const
virtual	~LightObject ()

Protected Attributes
WeightsType	m_ComponentWeights
WeightsType	m_DerivativeWeights
WeightsType	m_SqrtComponentWeights

Private Member Functions
void	operator= (const Self &)
	VectorGradientMagnitudeImageFilter (const Self &)

Private Attributes
RadiusType	m_NeighborhoodRadius
ImageBaseType::ConstPointer	m_RealValuedInputImage
ThreadIdType	m_RequestedNumberOfThreads
bool	m_UseImageSpacing
bool	m_UsePrincipleComponents

Detailed Description

template<typename TInputImage, typename TRealType = float, typename TOutputImage = Image< TRealType, ::itk::GetImageDimension< TInputImage >::ImageDimension >>
class itk::VectorGradientMagnitudeImageFilter< TInputImage, TRealType, TOutputImage >

Computes a scalar, gradient magnitude image from a multiple channel (pixels are vectors) input.

Overview: This filter has two calculation modes. The first (default) mode calculates gradient magnitude as the difference between the largest two eigenvalues in a principle component analysis of the partial derivatives [1]. The gradient is then based on the direction of maximal change, and is a characterization of how "elongated" the point-spread of the analysis is found to be.

The second, more heuristic, calculation mode finds gradient magnitude as the square-root of the sum of the * individual weighted vector component derivative sums squared. That is, * $\mathbf{magnitude} = \left( \sum_{i=0}^n \sum_{j=0}^m \frac{\delta * \phi_j}{\delta \mathbf{x}_{i}}^2 \right)^{\frac{1}{2}}$ , where $\phi_j$ * is the $j^{\mathbf{th}}$ channel of vector image $\phi$ of dimension $n$ . * Weighting terms are applied to each vector component.

The second mode is computationally much faster than the first and has the advantage that it is automatically multi-threaded (some vnl functions used in the first mode are not thread-safe). The first mode, however, tends to give intuitively better results with less (or no) parameter tuning.

Template Parameters (Input and Output): This filter has one required template parameter which defines the input image type. The pixel type of the input image is assumed to be a vector (e.g., itk::Vector, itk::RGBPixel, itk::FixedArray). The scalar type of the vector components must be castable to floating point. Instantiating with an image of RGBPixel<unsigned short>, for example, is allowed, but the filter will convert it to an image of Vector<float,3> for processing.

The second template parameter, TRealType, can be optionally specified to define the scalar numerical type used in calculations. This is the component type of the output image, which will be of itk::Vector<TRealType, N>, where N is the number of channels in the multiple component input image. The default type of TRealType is float. For extra precision, you may safely change this parameter to double.

The third template parameter is the output image type. The third parameter will be automatically constructed from the first and second parameters, so it is not necessary (or advisable) to set this parameter explicitly. Given an M-channel input image with dimensionality N, and a numerical type specified as TRealType, the output image will be of type itk::Image<itk::Vector<TRealType, M>, N>.

Filter Parameters: The methods Set/GetUsePrincipleComponents and SetUsePrincipleComponentsOn/Off determine controls the calculation mode that is used.

The method SetUseImageSpacingOn will cause derivatives in the image to be scaled (inversely) with the pixel size of the input image, effectively taking derivatives in world coordinates (versus isotropic image space). SetUseImageSpacingOff turns this functionality off. Default is UseImageSpacingOn. The parameter UseImageSpacing can be set directly with the method SetUseImageSpacing(bool).

Weights can be applied to the derivatives directly using the SetDerivativeWeights method. Note that if UseImageSpacing is set to TRUE (ON), then these weights will be overridden by weights derived from the image spacing when the filter is updated. The argument to this method is a C array of TRealValue type.

Weights can be applied to each vector component of the image when the component derivative values are summed during computation. Specify these weights using the SetComponentWeights method. The argument to this method is a C array of TRealValue type.

Constraints: The filter requires an image with at least two dimensions and a vector length of at least 2. The theory supports extension to scalar images, but the implementation of the itk vector classes do not

The template parameter TRealType must be floating point (float or double) or a user-defined "real" numerical type with arithmetic operations defined sufficient to compute derivatives.

Performance: This filter will automatically multithread if run with SetUsePrincipleComponents=Off or on 3D data in UsePrincipleComponents=On mode. Unfortunately the ND eigen solver used is not thread safe (a special 3D solver is), so it cannot multithread for data other than 3D in UsePrincipleComponents=On mode.

References

[1] G. Sapiro and D. Ringach, "Anisotropic Diffusion of Multivalued Images with Application to Color Filtering," IEEE Transactions on Image Processing, Vol 5, No. 11 pp. 1582-1586, 1996

See also:: Image; Neighborhood; NeighborhoodOperator; NeighborhoodIterator

Definition at line 139 of file itkVectorGradientMagnitudeImageFilter.h.