#include <itkCannyEdgeDetectionImageFilter.h>

Inheritance diagram for itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >:

Collaboration diagram for itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >:

Detailed Description

template<typename TInputImage, typename TOutputImage>
class itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >

This filter is an implementation of a Canny edge detector for scalar-valued images.

Based on John Canny's paper "A Computational Approach to Edge Detection"(IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. PAMI-8, No.6, November 1986), there are four major steps used in the edge-detection scheme: (1) Smooth the input image with Gaussian filter. (2) Calculate the second directional derivatives of the smoothed image. (3) Non-Maximum Suppression: the zero-crossings of 2nd derivative are found, and the sign of third derivative is used to find the correct extrema. (4) The hysteresis thresholding is applied to the gradient magnitude (multiplied with zero-crossings) of the smoothed image to find and link edges.

Inputs and Outputs: The input to this filter should be a scalar, real-valued Itk image of arbitrary dimension. The output should also be a scalar, real-value Itk image of the same dimensionality.

Parameters: There are four parameters for this filter that control the sub-filters used by the algorithm.

: Variance and Maximum error are used in the Gaussian smoothing of the input image. See itkDiscreteGaussianImageFilter for information on these parameters.

: Threshold is the lowest allowed value in the output image. Its data type is the same as the data type of the output image. Any values below the Threshold level will be replaced with the OutsideValue parameter value, whose default is zero.

Todo:: Edge-linking will be added when an itk connected component labeling algorithm is available.

See Also: DiscreteGaussianImageFilter; ZeroCrossingImageFilter; ThresholdImageFilter

Examples:: Examples/Filtering/CannyEdgeDetectionImageFilter.cxx, and SphinxExamples/src/Filtering/ImageFeature/DetectEdgesWithCannyFilter/Code.cxx.

Definition at line 86 of file itkCannyEdgeDetectionImageFilter.h.

Classes
struct	CannyThreadStruct

Public Types
typedef FixedArray< double, itkGetStaticConstMacro(ImageDimension) >	ArrayType

typedef SmartPointer< const Self >	ConstPointer

typedef ZeroFluxNeumannBoundaryCondition < OutputImageType >	DefaultBoundaryConditionType

typedef TInputImage::IndexType	IndexType

typedef TInputImage::PixelType	InputImagePixelType

typedef TInputImage::RegionType	InputImageRegionType

typedef TInputImage	InputImageType

typedef ObjectStore< ListNodeType >	ListNodeStorageType

typedef ListNode< IndexType >	ListNodeType

typedef ListType::Pointer	ListPointerType

typedef SparseFieldLayer < ListNodeType >	ListType

typedef ConstNeighborhoodIterator < OutputImageType, DefaultBoundaryConditionType >	NeighborhoodType

typedef TOutputImage::PixelType	OutputImagePixelType

typedef TOutputImage::RegionType	OutputImageRegionType

typedef TOutputImage	OutputImageType

typedef SmartPointer< Self >	Pointer

typedef CannyEdgeDetectionImageFilter	Self

typedef TInputImage::SizeValueType	SizeValueType

typedef ImageToImageFilter < TInputImage, TOutputImage >	Superclass

Public Types inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
typedef SmartPointer< const Self >	ConstPointer

typedef InputImageType::ConstPointer	InputImageConstPointer

typedef InputImageType::PixelType	InputImagePixelType

typedef InputImageType::Pointer	InputImagePointer

typedef InputImageType::RegionType	InputImageRegionType

typedef TInputImage	InputImageType

typedef Superclass::OutputImagePixelType	OutputImagePixelType

typedef Superclass::OutputImageRegionType	OutputImageRegionType

typedef SmartPointer< Self >	Pointer

typedef ImageToImageFilter	Self

typedef ImageSource< TOutputImage >	Superclass

Public Types inherited from itk::ImageSource< TOutputImage >
typedef SmartPointer< const Self >	ConstPointer

typedef Superclass::DataObjectIdentifierType	DataObjectIdentifierType

typedef DataObject::Pointer	DataObjectPointer

typedef Superclass::DataObjectPointerArraySizeType	DataObjectPointerArraySizeType

typedef OutputImageType::PixelType	OutputImagePixelType

typedef OutputImageType::Pointer	OutputImagePointer

typedef OutputImageType::RegionType	OutputImageRegionType

typedef TOutputImage	OutputImageType

typedef SmartPointer< Self >	Pointer

typedef ImageSource	Self

typedef ProcessObject	Superclass

Public Types inherited from itk::ProcessObject
typedef SmartPointer< const Self >	ConstPointer

typedef DataObject::DataObjectIdentifierType	DataObjectIdentifierType

typedef DataObject::Pointer	DataObjectPointer

typedef std::vector < DataObjectPointer >	DataObjectPointerArray

typedef DataObjectPointerArray::size_type	DataObjectPointerArraySizeType

typedef std::vector < DataObjectIdentifierType >	NameArray

typedef SmartPointer< Self >	Pointer

typedef ProcessObject	Self

typedef Object	Superclass

Public Types inherited from itk::Object
typedef SmartPointer< const Self >	ConstPointer

typedef SmartPointer< Self >	Pointer

typedef Object	Self

typedef LightObject	Superclass

Public Types inherited from itk::LightObject
typedef SmartPointer< const Self >	ConstPointer

typedef SmartPointer< Self >	Pointer

typedef LightObject	Self

Public Member Functions
virtual ::itk::LightObject::Pointer	CreateAnother () const

virtual void	GenerateInputRequestedRegion () override

virtual OutputImagePixelType	GetLowerThreshold () const

virtual const char *	GetNameOfClass () const

OutputImageType *	GetNonMaximumSuppressionImage ()

virtual OutputImagePixelType	GetUpperThreshold () const

virtual void	SetLowerThreshold (OutputImagePixelType _arg)

virtual void	SetUpperThreshold (OutputImagePixelType _arg)

	typedef (Concept::HasNumericTraits< InputImagePixelType >) InputHasNumericTraitsCheck

	typedef (Concept::HasNumericTraits< OutputImagePixelType >) OutputHasNumericTraitsCheck

	typedef (Concept::SameDimension< ImageDimension, OutputImageDimension >) SameDimensionCheck

	typedef (Concept::IsFloatingPoint< InputImagePixelType >) InputIsFloatingPointCheck

	typedef (Concept::IsFloatingPoint< OutputImagePixelType >) OutputIsFloatingPointCheck


virtual void	SetVariance (ArrayType _arg)

virtual const ArrayType	GetVariance () const

virtual void	SetMaximumError (ArrayType _arg)

virtual const ArrayType	GetMaximumError () const


void	SetVariance (const typename ArrayType::ValueType v)


void	SetMaximumError (const typename ArrayType::ValueType v)

Public Member Functions inherited from itk::ImageToImageFilter< TInputImage, TOutputImage >
const InputImageType *	GetInput () const

const InputImageType *	GetInput (unsigned int idx) const

virtual void	PopBackInput () override

virtual void	PopFrontInput () override

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)

virtual void	SetCoordinateTolerance (double _arg)

virtual double	GetCoordinateTolerance () const

virtual void	SetDirectionTolerance (double _arg)

virtual double	GetDirectionTolerance () const

Public Member Functions inherited from itk::ImageSource< TOutputImage >
OutputImageType *	GetOutput (unsigned int idx)

virtual void	GraftNthOutput (unsigned int idx, DataObject *output)

virtual void	GraftOutput (const DataObjectIdentifierType &key, DataObject *output)

OutputImageType *	GetOutput ()

const OutputImageType *	GetOutput () const

virtual void	GraftOutput (DataObject *output)

virtual ProcessObject::DataObjectPointer	MakeOutput (ProcessObject::DataObjectPointerArraySizeType idx) override

virtual ProcessObject::DataObjectPointer	MakeOutput (const ProcessObject::DataObjectIdentifierType &) override

Public Member Functions inherited from itk::ProcessObject
virtual void	AbortGenerateDataOff ()

virtual void	AbortGenerateDataOn ()

virtual void	EnlargeOutputRequestedRegion (DataObject *)

virtual const bool &	GetAbortGenerateData () const

DataObjectPointerArray	GetIndexedInputs ()

DataObjectPointerArray	GetIndexedOutputs ()

NameArray	GetInputNames () const

DataObjectPointerArray	GetInputs ()

MultiThreader *	GetMultiThreader () const

DataObjectPointerArraySizeType	GetNumberOfIndexedInputs () const

DataObjectPointerArraySizeType	GetNumberOfIndexedOutputs () const

DataObjectPointerArraySizeType	GetNumberOfInputs () const

DataObjectPointerArraySizeType	GetNumberOfOutputs () const

virtual DataObjectPointerArraySizeType	GetNumberOfValidRequiredInputs () const

NameArray	GetOutputNames () const

DataObjectPointerArray	GetOutputs ()

virtual const float &	GetProgress () const

NameArray	GetRequiredInputNames () const

bool	HasInput (const DataObjectIdentifierType &key) const

bool	HasOutput (const DataObjectIdentifierType &key) const

virtual void	PrepareOutputs ()

virtual void	PropagateRequestedRegion (DataObject *output)

virtual void	ResetPipeline ()

virtual void	SetAbortGenerateData (bool _arg)

virtual void	Update ()

virtual void	UpdateLargestPossibleRegion ()

virtual void	UpdateOutputData (DataObject *output)

virtual void	UpdateOutputInformation ()

void	UpdateProgress (float progress)

void	SetProgress (float progress)

virtual void	SetReleaseDataFlag (bool flag)

virtual bool	GetReleaseDataFlag () const

void	ReleaseDataFlagOn ()

void	ReleaseDataFlagOff ()

virtual void	SetReleaseDataBeforeUpdateFlag (bool _arg)

virtual const bool &	GetReleaseDataBeforeUpdateFlag () const

virtual void	ReleaseDataBeforeUpdateFlagOn ()

virtual void	ReleaseDataBeforeUpdateFlagOff ()

virtual void	SetNumberOfThreads (ThreadIdType _arg)

virtual const ThreadIdType &	GetNumberOfThreads () const

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 ()

const MetaDataDictionary &	GetMetaDataDictionary () const

virtual ModifiedTimeType	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 override

void	RemoveAllObservers ()

void	RemoveObserver (unsigned long tag)

void	SetDebug (bool debugFlag) const

void	SetMetaDataDictionary (const MetaDataDictionary &rhs)

virtual void	SetReferenceCount (int) override

virtual void	UnRegister () const noexceptoverride

virtual void	SetObjectName (std::string _arg)

virtual const std::string &	GetObjectName () 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 Pointer	New ()

Static Public Member Functions inherited from itk::Object
static bool	GetGlobalWarningDisplay ()

static void	GlobalWarningDisplayOff ()

static void	GlobalWarningDisplayOn ()

static Pointer	New ()

static void	SetGlobalWarningDisplay (bool flag)

Static Public Member Functions inherited from itk::LightObject
static void	BreakOnError ()

static Pointer	New ()

Static Public Attributes

static const unsigned int	ImageDimension = TInputImage::ImageDimension

static const unsigned int	OutputImageDimension = TOutputImage::ImageDimension

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 >
static const unsigned int	OutputImageDimension = TOutputImage::ImageDimension

Protected Types
typedef DiscreteGaussianImageFilter < InputImageType, OutputImageType >	GaussianImageFilterType

typedef MultiplyImageFilter < OutputImageType, OutputImageType, OutputImageType >	MultiplyImageFilterType

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
	CannyEdgeDetectionImageFilter ()

void	GenerateData () override

void	PrintSelf (std::ostream &os, Indent indent) const override

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 () override

	~ImageToImageFilter ()

void	PushBackInput (const DataObject *input) override

void	PushFrontInput (const DataObject *input) override

Protected Member Functions inherited from itk::ImageSource< TOutputImage >
virtual void	AfterThreadedGenerateData ()

virtual void	AllocateOutputs ()

virtual void	BeforeThreadedGenerateData ()

virtual const ImageRegionSplitterBase *	GetImageRegionSplitter () const

	ImageSource ()

virtual unsigned int	SplitRequestedRegion (unsigned int i, unsigned int pieces, OutputImageRegionType &splitRegion)

virtual void	ThreadedGenerateData (const OutputImageRegionType &outputRegionForThread, ThreadIdType threadId)

virtual	~ImageSource ()

Protected Member Functions inherited from itk::ProcessObject
virtual void	AddInput (DataObject *input)

virtual void	AddOutput (DataObject *output)

bool	AddRequiredInputName (const DataObjectIdentifierType &)

bool	AddRequiredInputName (const DataObjectIdentifierType &, DataObjectPointerArraySizeType idx)

virtual void	CacheInputReleaseDataFlags ()

virtual void	GenerateOutputInformation ()

virtual void	GenerateOutputRequestedRegion (DataObject *output)

DataObject *	GetInput (const DataObjectIdentifierType &key)

const DataObject *	GetInput (const DataObjectIdentifierType &key) const

virtual const DataObjectPointerArraySizeType &	GetNumberOfRequiredInputs () const

virtual const DataObjectPointerArraySizeType &	GetNumberOfRequiredOutputs () const

bool	IsIndexedInputName (const DataObjectIdentifierType &) const

bool	IsIndexedOutputName (const DataObjectIdentifierType &) const

bool	IsRequiredInputName (const DataObjectIdentifierType &) const

	itkLegacyMacro (virtual void RemoveOutput(DataObject *output))

	itkLegacyMacro (void SetNumberOfOutputs(DataObjectPointerArraySizeType num))

	itkLegacyMacro (virtual void RemoveInput(DataObject *input))

	itkLegacyMacro (void SetNumberOfInputs(DataObjectPointerArraySizeType num))

DataObjectPointerArraySizeType	MakeIndexFromInputName (const DataObjectIdentifierType &name) const

DataObjectPointerArraySizeType	MakeIndexFromOutputName (const DataObjectIdentifierType &name) const

DataObjectIdentifierType	MakeNameFromInputIndex (DataObjectPointerArraySizeType idx) const

DataObjectIdentifierType	MakeNameFromOutputIndex (DataObjectPointerArraySizeType idx) 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 (DataObjectPointerArraySizeType idx)

const DataObject *	GetInput (DataObjectPointerArraySizeType idx) const

DataObject *	GetPrimaryInput ()

const DataObject *	GetPrimaryInput () const

virtual void	SetPrimaryInputName (const DataObjectIdentifierType &key)

virtual const char *	GetPrimaryInputName (void) const

DataObject *	GetOutput (const DataObjectIdentifierType &key)

const DataObject *	GetOutput (const DataObjectIdentifierType &key) const

virtual void	SetPrimaryOutputName (const DataObjectIdentifierType &key)

virtual const char *	GetPrimaryOutputName (void) 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 ()

Private Member Functions
void	AllocateUpdateBuffer ()

	CannyEdgeDetectionImageFilter (const Self &)

void	Compute2ndDerivative ()

void	Compute2ndDerivativePos ()

OutputImagePixelType	ComputeCannyEdge (const NeighborhoodType &it, void *globalData)

void	FollowEdge (IndexType index, const OutputImageType *multiplyImageFilterOutput)

void	HysteresisThresholding ()

void	operator= (const Self &)

void	ThreadedCompute2ndDerivative (const OutputImageRegionType &outputRegionForThread, ThreadIdType threadId)

void	ThreadedCompute2ndDerivativePos (const OutputImageRegionType &outputRegionForThread, ThreadIdType threadId)

virtual	~CannyEdgeDetectionImageFilter ()

Static Private Member Functions
static ITK_THREAD_RETURN_TYPE	Compute2ndDerivativePosThreaderCallback (void *arg)

static ITK_THREAD_RETURN_TYPE	Compute2ndDerivativeThreaderCallback (void *arg)

Private Attributes
SizeValueType	m_Center

std::slice	m_ComputeCannyEdgeSlice [ImageDimension]

GaussianImageFilterType::Pointer	m_GaussianFilter

OutputImagePixelType	m_LowerThreshold

ArrayType	m_MaximumError

MultiplyImageFilterType::Pointer	m_MultiplyImageFilter

ListPointerType	m_NodeList

ListNodeStorageType::Pointer	m_NodeStore

OutputImageType *	m_OutputImage

SizeValueType	m_Stride [ImageDimension]

OutputImageType::Pointer	m_UpdateBuffer1

OutputImagePixelType	m_UpperThreshold

ArrayType	m_Variance


DerivativeOperator < OutputImagePixelType, itkGetStaticConstMacro(ImageDimension) >	m_ComputeCannyEdge1stDerivativeOper

DerivativeOperator < OutputImagePixelType, itkGetStaticConstMacro(ImageDimension) >	m_ComputeCannyEdge2ndDerivativeOper

Additional Inherited Members
Static Protected Member Functions inherited from itk::ImageSource< TOutputImage >
static const ImageRegionSplitterBase *	GetGlobalDefaultSplitter ()

static ITK_THREAD_RETURN_TYPE	ThreaderCallback (void *arg)

Protected Attributes inherited from itk::ProcessObject
TimeStamp	m_OutputInformationMTime

bool	m_Updating

Protected Attributes inherited from itk::LightObject
AtomicInt< int >	m_ReferenceCount