itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType > Class Template Reference

Segments structures in images based on image features derived from pseudo-canny-edges. More...

#include <itkCannySegmentationLevelSetImageFilter.h>

List of all members.

Public Types
typedef CannySegmentationLevelSetImageFilter	Self
typedef SegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType, Image< TOutputPixelType,::itk::GetImageDimension< TInputImage >::ImageDimension > >	Superclass
typedef SmartPointer< Self >	Pointer
typedef SmartPointer< const Self >	ConstPointer
typedef Superclass::ValueType	ValueType
typedef Superclass::OutputImageType	OutputImageType
typedef Superclass::FeatureImageType	FeatureImageType
typedef Superclass::VectorImageType	VectorImageType
typedef ::itk::CannySegmentationLevelSetFunction< OutputImageType, FeatureImageType >	CannyFunctionType
typedef CannyFunctionType::ScalarValueType	ScalarValueType
Public Member Functions
virtual const char *	GetClassName () const
void	SetThreshold (ScalarValueType v)
ScalarValueType	GetThreshold () const
void	SetVariance (double v)
double	GetVariance () const
Static Public Member Functions
Pointer	New ()
Protected Member Functions
	~CannySegmentationLevelSetImageFilter ()
	CannySegmentationLevelSetImageFilter ()

---

Detailed Description

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float>
class itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >

Segments structures in images based on image features derived from pseudo-canny-edges.

IMPORTANT

The SegmentationLevelSetImageFilter class and the CannySegmentationLevelSetFunction class contain additional information necessary to the full understanding of how to use this filter.

OVERVIEW

This class is a level set method segmentation filter. It constructs a speed function which is designed to lock onto edges as detected by a Canny filter.

The CannySegmentationLevelSetImageFilter can be a tool for refining an existing segmentation, or it can be used to try to segment a region by itself. Like all other level-set based segmentation filters (see SegmentationLevelSetImageFilter), it works by first constructing a scalar speed term and a vector advection field based on edge features in the image. The level set front is then moved according to these two terms with the addition of a third curvature term to contol the smoothness of the solution.

The speed term is constructed as the Danielsson distance transform of the Canny edge image, as calculated by the CannyEdgeDetectionImageFilter. This scalar speed can be tuned in and out of the final evolution equation by setting the PropagationScaling parameter (a value of 0 removes the speed term).

The advection field term is constructed by minimizing Danielsson distance squared. i.e. . This term moves the level set down the gradient of the distance transform.

In practice, you may set the speed (propagation) term to zero if your initialization is already close to the edge you are interested in. If you are trying to segment a region by seeding with a small surface (blob, sphere) then you will likely want to add speed (propagation) to the equation so that the levelsets can expand along zero gradients. The relative influence of these two terms are controlled by the SetPropagationScaling and SetAdvectionScaling parameters.

INPUTS

This filter requires two inputs. The first input is a seed image. This seed image must contain an isosurface that you want to use as the seed for your segmentation. It can be a binary, graylevel, or floating point image. The only requirement is that it contain a closed isosurface that you will identify as the seed by setting the IsosurfaceValue parameter of the filter. For a binary image you will want to set your isosurface value halfway between your on and off values (i.e. for 0's and 1's, use an isosurface value of 0.5).

The second input is the feature image. This is the image from which the speed function will be calculated. For most applications, this is the image that you want to segment. The desired isosurface in your seed image should lie within the region of your feature image that you are trying to segment.

See SegmentationLevelSetImageFilter for more information on Inputs.

OUTPUTS

The filter outputs a single, scalar, real-valued image. Positive *values in the output image are inside the segmentated region and negative *values in the image are outside of the inside region. The zero crossings of *the image correspond to the position of the level set front.

See SparseFieldLevelSetImageFilter and SegmentationLevelSetImageFilter for more information.

PARAMETERS

There are five parameters important for controlling the behavior of this filter.

(1) Threshold. Sets the thresholding value of the Canny edge detection. See CannyEdgeDetectionImageFilter for more information.

(2) Variance. Controls the smoothing paramter of the gaussian filtering done during Canny edge detection.

(3) CurvatureScaling. Controls the degree to which curvature influences the evolution of the level set. Higher values relative to Propagation and Advection scalings will yield a smoother surface.

(4) PropagationScaling. Scales the propagation (speed) term of the level set equation. Set this term to zero to allow the level set to flow _only_ down the gradient of the distance transform.

(5) AdvectionScaling. Scales influence of the advection field relative to curvature and propagation terms.

See also:

SegmentationLevelSetImageFilter

CannySegmentationLevelSetFunction,

SparseFieldLevelSetImageFilter

Definition at line 129 of file itkCannySegmentationLevelSetImageFilter.h.

---

Member Typedef Documentation

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef ::itk::CannySegmentationLevelSetFunction<OutputImageType, FeatureImageType> itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::CannyFunctionType

Type of the segmentation function Definition at line 150 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef SmartPointer<const Self> itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::ConstPointer

Definition at line 140 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef Superclass::FeatureImageType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::FeatureImageType

Definition at line 145 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef Superclass::OutputImageType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::OutputImageType

Definition at line 144 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef SmartPointer<Self> itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::Pointer

Definition at line 139 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef CannyFunctionType::ScalarValueType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::ScalarValueType

Definition at line 152 of file itkCannySegmentationLevelSetImageFilter.h. Referenced by itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::GetThreshold(), and itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::SetThreshold().

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef CannySegmentationLevelSetImageFilter itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::Self

Standard class typedefs Definition at line 135 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef SegmentationLevelSetImageFilter<TInputImage, TFeatureImage, TOutputPixelType, Image<TOutputPixelType, ::itk::GetImageDimension<TInputImage>::ImageDimension> > itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::Superclass

Definition at line 138 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef Superclass::ValueType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::ValueType

Inherited typedef from the superclass. Definition at line 143 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> typedef Superclass::VectorImageType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::VectorImageType

Definition at line 146 of file itkCannySegmentationLevelSetImageFilter.h.

---

Constructor & Destructor Documentation

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::~CannySegmentationLevelSetImageFilter (   )  [inline, protected]

Definition at line 177 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::CannySegmentationLevelSetImageFilter (   )  [protected]

---

Member Function Documentation

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> virtual const char* itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::GetClassName (   )  const [virtual]

Run-time type information (and related methods).

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> ScalarValueType itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::GetThreshold (   )  const [inline]

Set the Threshold parameter of the CannyEdgeDetectionImageFilter used by the underlying level set function. Definition at line 164 of file itkCannySegmentationLevelSetImageFilter.h. References itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::ScalarValueType.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> double itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::GetVariance (   )  const [inline]

Set the Variance parameter of the CannyEdgeDetectionImageFilter used by the underlying level set function. Definition at line 172 of file itkCannySegmentationLevelSetImageFilter.h.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> Pointer itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::New (   )  [static]

Method for creation through the object factory

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> void itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::SetThreshold (  ScalarValueType  v  )  [inline]

Set the Threshold parameter of the CannyEdgeDetectionImageFilter used by the underlying level set function. Definition at line 162 of file itkCannySegmentationLevelSetImageFilter.h. References itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::ScalarValueType.

template<class TInputImage, class TFeatureImage, class TOutputPixelType = float> void itk::CannySegmentationLevelSetImageFilter< TInputImage, TFeatureImage, TOutputPixelType >::SetVariance (  double  v  )  [inline]

Set the Variance parameter of the CannyEdgeDetectionImageFilter used by the underlying level set function. Definition at line 170 of file itkCannySegmentationLevelSetImageFilter.h.

---

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

• itkCannySegmentationLevelSetImageFilter.h

---