ITK
6.0.0
Insight 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 horizontal 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 97 of file itkSobelOperator.h.
Protected Types | |
using | CoefficientVector = typename std::vector< PixelRealType > |
Protected Types inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > > | |
using | CoefficientVector = typename std::vector< PixelRealType > |
Protected Member Functions | |
void | Fill (const CoefficientVector &coeff) override |
CoefficientVector | GenerateCoefficients () override |
Protected Member Functions inherited from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > > | |
virtual void | Fill (const CoefficientVector &)=0 |
virtual void | FillCenteredDirectional (const CoefficientVector &) |
virtual CoefficientVector | GenerateCoefficients ()=0 |
void | InitializeToZero () |
Protected Member Functions inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > > | |
virtual void | Allocate (NeighborIndexType i) |
virtual void | ComputeNeighborhoodOffsetTable () |
virtual void | ComputeNeighborhoodStrideTable () |
virtual void | PrintSelf (std::ostream &, Indent) const |
void | SetSize () |
Additional Inherited Members | |
Static Public Attributes inherited from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > > | |
static constexpr unsigned int | NeighborhoodDimension |
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protected |
Type alias support for coefficient vector type. Necessary to fix bug in the microsoft VC++ compiler.
Definition at line 153 of file itkNeighborhoodOperator.h.
using itk::SobelOperator< TPixel, VDimension, TAllocator >::Self = SobelOperator |
Standard class type aliases.
Definition at line 102 of file itkSobelOperator.h.
using itk::SobelOperator< TPixel, VDimension, TAllocator >::Superclass = NeighborhoodOperator<TPixel, VDimension, TAllocator> |
Definition at line 103 of file itkSobelOperator.h.
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inlineoverridevirtual |
Creates the operator with length only in the specified direction. The radius of the operator will be 0 except along the axis on which the operator will work.
Reimplemented from itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >.
Definition at line 112 of file itkSobelOperator.h.
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overrideprotectedvirtual |
Arranges coefficients spatially in the memory buffer.
Implements itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >.
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overrideprotectedvirtual |
Calculates operator coefficients.
Implements itk::NeighborhoodOperator< TPixel, 2, NeighborhoodAllocator< TPixel > >.
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overridevirtual |
Reimplemented from itk::Neighborhood< TPixel, VDimension, NeighborhoodAllocator< TPixel > >.