itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage > Class Template Reference

#include <itkCannyEdgeDetectionImageFilter.h>

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

[legend]Collaboration diagram for itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >:

[legend]List of all members.

Public Types
typedef CannyEdgeDetectionImageFilter	Self
typedef ImageToImageFilter< TInputImage, TOutputImage >	Superclass
typedef TInputImage	InputImageType
typedef TOutputImage	OutputImageType
typedef SmartPointer< Self >	Pointer
typedef SmartPointer< const Self >	ConstPointer
typedef TInputImage::PixelType	InputImagePixelType
typedef TOutputImage::PixelType	OutputImagePixelType
typedef TInputImage::IndexType	IndexType
typedef ZeroFluxNeumannBoundaryCondition< OutputImageType >	DefaultBoundaryConditionType
typedef ConstNeighborhoodIterator< OutputImageType, DefaultBoundaryConditionType >	NeighborhoodType
typedef ListNode< IndexType >	ListNodeType
typedef ObjectStore< ListNodeType >	ListNodeStorageType
typedef SparseFieldLayer< ListNodeType >	ListType
typedef ListType::Pointer	ListPointerType
typedef TOutputImage::RegionType	OutputImageRegionType
Public Member Functions
virtual const char *	GetClassName () const
	itkStaticConstMacro (ImageDimension, unsigned int, TInputImage::ImageDimension)
virtual void	SetThreshold (OutputImagePixelType _arg)
virtual OutputImagePixelType	GetThreshold ()
virtual void	SetOutsideValue (OutputImagePixelType _arg)
virtual OutputImagePixelType	GetOutsideValue ()
virtual void	GenerateInputRequestedRegion () throw (InvalidRequestedRegionError)
virtual void	SetVariance (double data[])
virtual const double *	GetVariance () const
virtual void	SetMaximumError (double data[])
virtual const double *	GetMaximumError () const
void	SetVariance (const double v)
void	SetMaximumError (const double v)
Static Public Member Functions
Pointer	New ()
Protected Member Functions
	CannyEdgeDetectionImageFilter ()
	CannyEdgeDetectionImageFilter (const Self &)
void	PrintSelf (std::ostream &os, Indent indent) const
void	GenerateData ()

---

Detailed Description

template<class TInputImage, class 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) Smoothe 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

Definition at line 86 of file itkCannyEdgeDetectionImageFilter.h.

---

Member Typedef Documentation

template<class TInputImage, class TOutputImage> typedef SmartPointer<const Self> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::ConstPointer

Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 100 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ZeroFluxNeumannBoundaryCondition<OutputImageType> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::DefaultBoundaryConditionType

The default boundary condition is used unless overridden in the Evaluate() method. Definition at line 110 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TInputImage::IndexType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::IndexType

Definition at line 105 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TInputImage::PixelType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::InputImagePixelType

Define pixel types. Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 103 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TInputImage itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::InputImageType

Image typedef support Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 95 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ObjectStore<ListNodeType> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::ListNodeStorageType

Definition at line 119 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ListNode<IndexType> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::ListNodeType

Definition at line 118 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ListType::Pointer itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::ListPointerType

Definition at line 121 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef SparseFieldLayer<ListNodeType> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::ListType

Definition at line 120 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ConstNeighborhoodIterator<OutputImageType, DefaultBoundaryConditionType> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::NeighborhoodType

The type of data structure that is passed to this function object to evaluate at a pixel that does not lie on a data set boundary. Definition at line 116 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TOutputImage::PixelType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::OutputImagePixelType

Reimplemented from itk::ImageSource< TOutputImage >. Definition at line 104 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TOutputImage::RegionType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::OutputImageRegionType

Typedef to describe the output image region type. Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 127 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef TOutputImage itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::OutputImageType

Some convenient typedefs. Reimplemented from itk::ImageSource< TOutputImage >. Definition at line 96 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef SmartPointer<Self> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::Pointer

SmartPointer typedef support Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 99 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef CannyEdgeDetectionImageFilter itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::Self

Standard "Self" & Superclass typedef. Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 91 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> typedef ImageToImageFilter<TInputImage, TOutputImage> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::Superclass

Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >. Definition at line 92 of file itkCannyEdgeDetectionImageFilter.h.

---

Constructor & Destructor Documentation

template<class TInputImage, class TOutputImage> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::CannyEdgeDetectionImageFilter (   )  [protected]

template<class TInputImage, class TOutputImage> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::CannyEdgeDetectionImageFilter (  const Self &   )  [inline, protected]

Definition at line 189 of file itkCannyEdgeDetectionImageFilter.h.

---

Member Function Documentation

template<class TInputImage, class TOutputImage> void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GenerateData (   )  [protected, virtual]

A version of GenerateData() specific for image processing filters. This implementation will split the processing across multiple threads. The buffer is allocated by this method. Then the BeforeThreadedGenerateData() method is called (if provided). Then, a series of threads are spawned each calling ThreadedGenerateData(). After all the threads have completed processing, the AfterThreadedGenerateData() method is called (if provided). If an image processing filter cannot be threaded, the filter should provide an implementation of GenerateData(). That implementation is responsible for allocating the output buffer. If a filter an be threaded, it should NOT provide a GenerateData() method but should provide a ThreadedGenerateData() instead. See also: ThreadedGenerateData() Reimplemented from itk::ImageSource< TOutputImage >.

template<class TInputImage, class TOutputImage> virtual void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GenerateInputRequestedRegion (   )  throw (InvalidRequestedRegionError) [virtual]

CannyEdgeDetectionImageFilter needs a larger input requested region than the output requested region ( derivative operators, etc). As such, CannyEdgeDetectionImageFilter needs to provide an implementation for GenerateInputRequestedRegion() in order to inform the pipeline execution model. See also: ImageToImageFilter::GenerateInputRequestedRegion() Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >.

template<class TInputImage, class TOutputImage> virtual const char* itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GetClassName (   )  const [virtual]

Run-time type information (and related methods). Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >.

template<class TInputImage, class TOutputImage> virtual const double* itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GetMaximumError (   )  const [virtual]

Standard get/set macros for filter parameters.

template<class TInputImage, class TOutputImage> virtual OutputImagePixelType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GetOutsideValue (   )  [virtual]

template<class TInputImage, class TOutputImage> virtual OutputImagePixelType itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GetThreshold (   )  [virtual]

template<class TInputImage, class TOutputImage> virtual const double* itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::GetVariance (   )  const [virtual]

Standard get/set macros for filter parameters.

template<class TInputImage, class TOutputImage> itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::itkStaticConstMacro (  ImageDimension  , unsigned  int, TInputImage::ImageDimension  )

ImageDimension constant

template<class TInputImage, class TOutputImage> Pointer itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::New (   )  [static]

Method for creation through the object factory. Reimplemented from itk::Object.

template<class TInputImage, class TOutputImage> void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::PrintSelf (  std::ostream &  os, Indent  indent )  const [protected, virtual]

Methods invoked by Print() to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes. Reimplemented from itk::ImageToImageFilter< TInputImage, TOutputImage >.

template<class TInputImage, class TOutputImage> void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetMaximumError (  const double  v  )  [inline]

Set/Get the MaximumError paramter used by the Gaussian smoothing filter in this algorithm Definition at line 155 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> virtual void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetMaximumError (  double  data[]  )  [virtual]

Standard get/set macros for filter parameters.

template<class TInputImage, class TOutputImage> virtual void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetOutsideValue (  OutputImagePixelType  _arg  )  [virtual]

* Set the Threshold value for detected edges. */

template<class TInputImage, class TOutputImage> virtual void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetThreshold (  OutputImagePixelType  _arg  )  [virtual]

template<class TInputImage, class TOutputImage> void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetVariance (  const double  v  )  [inline]

Set/Get the Variance parameter used by the Gaussian smoothing filter in this algorithm Definition at line 145 of file itkCannyEdgeDetectionImageFilter.h.

template<class TInputImage, class TOutputImage> virtual void itk::CannyEdgeDetectionImageFilter< TInputImage, TOutputImage >::SetVariance (  double  data[]  )  [virtual]

Standard get/set macros for filter parameters.

---

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

• itkCannyEdgeDetectionImageFilter.h

---