1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
/*
* Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
*
* This file is part of Orfeo Toolbox
*
* https://www.orfeo-toolbox.org/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef otbSVMCrossValidationCostFunction_h
#define otbSVMCrossValidationCostFunction_h
#include "itkSingleValuedCostFunction.h"
namespace otb
{
/** \class SVMCrossValidationCostFunction
* \brief This function returns the cross validation accuracy of a SVM model.
*
* It allows performing parameters selection to maximize the
* accuracy using ITK optimizers.
*
* Given an input SVM model, the number of parameters depends on the
* type of kernel:
* - Linear kernel : C
* - Polynomial kernel : C, gamma, coef0
* - RBF kernel : C, Gamma
* - Gaussian kernel : C, Gamma, coef0
* - Other kernels : C
*
* Please note that this function is only defined on \f$ R_{+}^{*} \f$.
*
* The GetDerivative() uses the GetValue() function to
* compute the partial derivatives. as such, it can be quite intensive.
*
* \ingroup ClassificationFilters
*
* \ingroup OTBSupervised
*/
template <class TModel>
class ITK_EXPORT SVMCrossValidationCostFunction : public itk::SingleValuedCostFunction
{
public:
/** Standard class typedefs. */
typedef SVMCrossValidationCostFunction Self;
typedef itk::SingleValuedCostFunction Superclass;
typedef itk::SmartPointer<Self> Pointer;
typedef itk::SmartPointer<const Self> ConstPointer;
/** Method for creation through the object factory. */
itkNewMacro(Self);
/** Type definitions for the SVM Model. */
typedef TModel SVMModelType;
typedef typename SVMModelType::Pointer SVMModelPointer;
/** Superclass typedefs */
typedef typename Superclass::MeasureType MeasurementType;
typedef typename Superclass::ParametersType ParametersType;
typedef typename Superclass::ParametersValueType ParametersValueType;
typedef typename Superclass::DerivativeType DerivativeType;
/** Set the model */
itkSetObjectMacro(Model, SVMModelType);
itkGetObjectMacro(Model, SVMModelType);
/** Set/Get the derivative step */
itkSetMacro(DerivativeStep, ParametersValueType);
itkGetMacro(DerivativeStep, ParametersValueType);
/** \return The accuracy value corresponding the parameters */
MeasureType GetValue(const ParametersType& parameters) const override;
/** \return The accuracy derivative corresponding to the parameters */
void GetDerivative(const ParametersType& parameters, DerivativeType& derivative) const override;
/** \return the number of parameters to optimize */
unsigned int GetNumberOfParameters(void) const override;
protected:
/// Constructor
SVMCrossValidationCostFunction();
/// Destructor
~SVMCrossValidationCostFunction() override;
/** Update svm parameters struct according to the input parameters
*/
void UpdateParameters(const ParametersType& parameters) const;
private:
SVMCrossValidationCostFunction(const Self&) = delete;
void operator=(const Self&) = delete;
/**Pointer to the SVM model to optimize */
SVMModelPointer m_Model;
/** Step used to compute the derivatives */
ParametersValueType m_DerivativeStep;
}; // class SVMCrossValidationCostFunction
} // namespace otb
#ifndef OTB_MANUAL_INSTANTIATION
#include "otbSVMCrossValidationCostFunction.hxx"
#endif
#endif
|
