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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkGaborKernelFunction.h
Language: C++
Date: $Date$
Version: $Revision$
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#ifndef __itkGaborKernelFunction_h
#define __itkGaborKernelFunction_h
#include "itkKernelFunction.h"
#include "vnl/vnl_math.h"
#include <math.h>
namespace itk
{
/** \class GaborKernelFunction
* \brief Gabor kernel used for various computer vision tasks.
*
* This class encapsulates a complex Gabor kernel used for
* various computer vision tasks such as texture segmentation,
* motion analysis, and object recognition. It is essentially
* a complex sinusoid enveloped within a gaussian.
* See the discussion in
*
* Andreas Klein, Forester Lee, and Amir A. Amini, "Quantitative
* Coronary Angiography with Deformable Spline Models", IEEE-TMI
* 16(5):468-482, October 1997.
*
* for a basic discussion including additional references.
*
* This implementation was contributed as a paper to the Insight Journal
* http://hdl.handle.net/1926/500
*
* \sa KernelFunction
*
* \ingroup Functions
*/
class ITK_EXPORT GaborKernelFunction : public KernelFunction
{
public:
/** Standard class typedefs. */
typedef GaborKernelFunction Self;
typedef KernelFunction Superclass;
typedef SmartPointer<Self> Pointer;
/** Method for creation through the object factory. */
itkNewMacro( Self );
/** Run-time type information (and related methods). */
itkTypeMacro( GaborKernelFunction, KernelFunction );
/** Evaluate the function. */
inline double Evaluate ( const double &u ) const
{
double parameter = vnl_math_sqr( u / this->m_Sigma );
double envelope = vcl_exp( -0.5 * parameter );
double phase = 2.0 * vnl_math::pi * this->m_Frequency * u
+ this->m_PhaseOffset;
if ( this->m_CalculateImaginaryPart )
{
return envelope * vcl_sin( phase );
}
else
{
return envelope * vcl_cos( phase );
}
}
itkSetMacro( Sigma, double );
itkGetConstMacro( Sigma, double );
itkSetMacro( Frequency, double );
itkGetConstMacro( Frequency, double );
itkSetMacro( PhaseOffset, double );
itkGetConstMacro( PhaseOffset, double );
itkSetMacro( CalculateImaginaryPart, bool );
itkGetConstMacro( CalculateImaginaryPart, bool );
itkBooleanMacro( CalculateImaginaryPart );
protected:
GaborKernelFunction();
~GaborKernelFunction();
void PrintSelf( std::ostream& os, Indent indent ) const;
private:
GaborKernelFunction( const Self& ); //purposely not implemented
void operator=( const Self& ); //purposely not implemented
/** Standard deviation of the Gaussian envelope */
double m_Sigma;
/** Modulation frequency of the sine or cosine component */
double m_Frequency;
/** Phase offset of the sine or cosine component */
double m_PhaseOffset;
/** Evaluate using the complex part */
bool m_CalculateImaginaryPart;
};
} // end namespace itk
#endif
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