ITK
4.3.0
Insight Segmentation and Registration Toolkit
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#include <itkSobelOperator.h>
A NeighborhoodOperator for performing a directional Sobel edge-detection operation at a pixel location.
SobelOperator is a directional NeighborhoodOperator that should be applied a NeighborhoodIterator using the NeighborhoodInnerProduct method. To create the operator:
1) Set the direction by calling
2) call
3) You may optionally scale the coefficients of this operator using the
method. This is useful if you want to take the spacing of the image into account when computing the edge strength. Apply the scaling only after calling to
.
The Sobel Operator in vertical direction for 2 dimensions is
* -1 -2 -1 * 0 0 0 * 1 2 1 * *
The Sobel Operator in horizonal direction is for 2 dimensions is
* -1 0 1 * -2 0 2 * -1 0 1 *
The current implementation of the Sobel operator is for 2 and 3 dimensions only. The ND version is planned for future releases.
The extension to 3D is from the publication "Irwin Sobel. An Isotropic 3x3x3 Volume Gradient Operator. Technical report, Hewlett-Packard Laboratories, April 1995."
The Sobel operator in 3D has the kernel
* -1 -3 -1 0 0 0 1 3 1 * -3 -6 -3 0 0 0 3 6 3 * -1 -3 -1 0 0 0 1 3 1 * * x-1 x x+1 *
The x
kernel is just rotated as required to obtain the kernel in the y
and z
directions.
Definition at line 96 of file itkSobelOperator.h.
Public Types | |
typedef SobelOperator | Self |
typedef NeighborhoodOperator < TPixel, VDimension, TAllocator > | Superclass |
Public Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator > | |
typedef NumericTraits< TPixel > ::RealType | PixelRealType |
typedef TPixel | PixelType |
typedef NeighborhoodOperator | Self |
typedef Superclass::SizeType | SizeType |
typedef SliceIterator< TPixel, Self > | SliceIteratorType |
typedef Neighborhood< TPixel, VDimension, TAllocator > | Superclass |
Public Types inherited from itk::Neighborhood< TPixel, VDimension, TAllocator > | |
typedef TAllocator | AllocatorType |
typedef AllocatorType::const_iterator | ConstIterator |
typedef unsigned int | DimensionValueType |
typedef AllocatorType::iterator | Iterator |
typedef SizeValueType | NeighborIndexType |
typedef Offset< VDimension > | OffsetType |
typedef TPixel | PixelType |
typedef Neighborhood | Self |
typedef SizeType::SizeValueType | SizeValueType |
typedef SliceIterator< TPixel, Self > | SliceIteratorType |
Protected Types | |
typedef Superclass::CoefficientVector | CoefficientVector |
typedef Superclass::PixelType | PixelType |
Protected Types inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator > | |
typedef std::vector< double > | CoefficientVector |
Protected Member Functions | |
void | Fill (const CoefficientVector &c) |
CoefficientVector | GenerateCoefficients () |
Protected Member Functions inherited from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator > | |
virtual void | FillCenteredDirectional (const CoefficientVector &) |
void | InitializeToZero () |
Protected Member Functions inherited from itk::Neighborhood< TPixel, VDimension, TAllocator > | |
virtual void | Allocate (NeighborIndexType i) |
virtual void | ComputeNeighborhoodOffsetTable () |
virtual void | ComputeNeighborhoodStrideTable () |
void | SetSize () |
Additional Inherited Members | |
Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, TAllocator > | |
typedef::itk::Size< VDimension > | RadiusType |
typedef::itk::Size< VDimension > | SizeType |
Static Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, TAllocator > | |
static const unsigned int | NeighborhoodDimension = VDimension |
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protected |
Typedef support for coefficient vector type. Necessary to work around compiler bug on VC++.
Definition at line 153 of file itkSobelOperator.h.
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protected |
Definition at line 154 of file itkSobelOperator.h.
typedef SobelOperator itk::SobelOperator< TPixel, VDimension, TAllocator >::Self |
Standard typedefs
Definition at line 102 of file itkSobelOperator.h.
typedef NeighborhoodOperator< TPixel, VDimension, TAllocator > itk::SobelOperator< TPixel, VDimension, TAllocator >::Superclass |
Definition at line 103 of file itkSobelOperator.h.
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inline |
Definition at line 107 of file itkSobelOperator.h.
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inline |
Definition at line 108 of file itkSobelOperator.h.
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inlinevirtual |
Creates the operator with length only in the specified direction. For the Sobel operator, this The radius of the operator will be 0 except along the axis on which the operator will work.
Reimplemented from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.
Definition at line 117 of file itkSobelOperator.h.
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protectedvirtual |
Arranges coefficients spatially in the memory buffer.
Implements itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.
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protectedvirtual |
Calculates operator coefficients.
Implements itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.
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virtual |
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inline |
Creates the operator with a specified radius ("square", same length on each side). The spatial location of the coefficients within the operator is defined by the subclass implementation of the Fill method.
Definition at line 131 of file itkSobelOperator.h.
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inlinevirtual |
Prints some debugging information
Reimplemented from itk::NeighborhoodOperator< TPixel, VDimension, TAllocator >.
Definition at line 141 of file itkSobelOperator.h.