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/*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: $RCSfile: itkCumulativeGaussianCostFunction.h,v $
Language: C++
Date: $Date: 2009-05-12 17:19:44 $
Version: $Revision: 1.8 $
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 __itkCumulativeGaussianCostFunction_h
#define __itkCumulativeGaussianCostFunction_h
#include "itkMultipleValuedCostFunction.h"
namespace itk
{
/** \class CumulativeGaussianCostFunction
* \brief Cost function for the Cumulative Gaussian Optimizer.
*
* The Cumulative Gaussian is defined as the integral of
* a normalized Gaussian over the domain \f$ [-\infty, \infty] \f$.
*
* \par Let G(x) be the normalized Gaussian defined as
* \f$ G(x) = \frac{1}{{\sigma \sqrt {2\pi } }}e^{ - \frac{{\left( {x -
* \mu } \right)^2 }}{{2\sigma ^2 }}} \f$.
* The Cumulative Gaussian, is acquired by integrating G(x) then scaling and
* offseting it by the lower asymptotes \f$ I_1 \f$ and upper \f$ I_2 \f$:
* \f$ C\left( x \right) = I_1 + \frac{{I_2 - I_1 }}{2}\left( {1 +
* erf\left( {\frac{{x - \mu }}{{\sigma \sqrt 2 }}} \right)} \right) \f$, where
* \f$ C\left( { - \infty } \right) = I_1 \f$ and
* \f$ C\left( \infty \right) = I_2 \f$.
*
* \par C(x) can only be tabulated since it's a variation of the
* error function. It is included in this class
* as the function EvaluateCumulativeGaussian, where the argument
* of the function is \f$ {\frac{{x - \mu }}{{\sigma \sqrt 2 }}} \f$.
*
* \ingroup Numerics Cost Functions
*/
class ITK_EXPORT CumulativeGaussianCostFunction : public MultipleValuedCostFunction
{
public:
/** Standard typedefs. */
typedef CumulativeGaussianCostFunction Self;
typedef MultipleValuedCostFunction Superclass;
typedef SmartPointer<Self> Pointer;
typedef SmartPointer<const Self> ConstPointer;
/** Run-time type information (and related methods). */
itkTypeMacro( CumulativeGaussianCostFunction, MultipleValuedCostFunction );
/** Method for creation through the object factory. */
itkNewMacro(Self);
/** Array Typedefs. */
typedef Superclass::ParametersType ParametersType;
typedef Superclass::MeasureType MeasureType;
typedef Superclass::DerivativeType DerivativeType;
/** The dimensions of parameter space; mean, standard deviation, lower and upper asymptotes. */
enum {SpaceDimension = 4};
/** Not necessary for this optimizer. */
void GetDerivative( const ParametersType & itkNotUsed(parameters),
DerivativeType & itkNotUsed(derivative)) const {};
/** Return the values evaluated for the given parameters. */
MeasureType GetValue( const ParametersType & parameters ) const;
/** Return a pointer of values evaluated for the given parameters. */
MeasureType * GetValue( ParametersType & parameters );
/** Calculate a fit error between the data and the fit curve. */
double CalculateFitError(MeasureType * setTestArray);
/** Given the argument of a Cumulative Gaussian, return its value. */
double EvaluateCumulativeGaussian(double argument) const;
/** Get the SpaceDimension. */
unsigned int GetNumberOfParameters() const;
/** Get the number Range Dimension. */
unsigned int GetNumberOfValues() const;
/** Initialize the arrays. */
void Initialize(unsigned int rangeDimension);
/** Set the original data array. */
void SetOriginalDataArray(MeasureType * setOriginalDataArray);
protected:
CumulativeGaussianCostFunction();
virtual ~CumulativeGaussianCostFunction();
void PrintSelf(std::ostream &os, Indent indent) const;
private:
/** Pointer to the original data array. */
MeasureType * m_OriginalDataArray;
/** Number of data samples. */
unsigned int m_RangeDimension;
/** Different arrays. */
mutable MeasureType m_Measure;
mutable MeasureType * m_MeasurePointer;
mutable ParametersType m_Parameters;
};
} // end namespace itk
#endif
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