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00017 #ifndef __itkKalmanLinearEstimator_h
00018 #define __itkKalmanLinearEstimator_h
00019
00020 #include "itkMacro.h"
00021
00022 #include <vnl/vnl_vector_fixed.h>
00023 #include <vnl/vnl_matrix_fixed.h>
00024
00025 namespace itk
00026 {
00027
00040 template <class T, unsigned int VEstimatorDimension>
00041 class ITK_EXPORT KalmanLinearEstimator
00042 {
00043 public:
00046 itkStaticConstMacro( Dimension, unsigned int,
00047 VEstimatorDimension);
00048
00051 typedef vnl_vector_fixed<T,VEstimatorDimension> VectorType;
00052
00055 typedef vnl_matrix_fixed<T,VEstimatorDimension,VEstimatorDimension> MatrixType;
00056
00061 typedef T ValueType;
00062
00067 void UpdateWithNewMeasure( const ValueType & newMeasure,
00068 const VectorType & newPredictor );
00069
00073 void ClearEstimation(void)
00074 { m_Estimator = VectorType(T(0)); }
00075
00078 void ClearVariance(void)
00079 {
00080 m_Variance.set_identity();
00081 }
00082
00089 void SetVariance(const ValueType & var = 1.0)
00090 {
00091 m_Variance.set_identity();
00092 m_Variance *= var;
00093 }
00095
00101 void SetVariance(const MatrixType & m)
00102 { m_Variance = m; }
00103
00106 const VectorType & GetEstimator(void) const
00107 { return m_Estimator; }
00108
00111 const MatrixType & GetVariance(void) const
00112 { return m_Variance; }
00113
00114 private:
00119 void UpdateVariance( const VectorType & );
00120
00123 VectorType m_Estimator;
00124
00131 MatrixType m_Variance;
00132
00133 };
00134
00135
00136 template <class T, unsigned int VEstimatorDimension>
00137 void
00138 KalmanLinearEstimator<T,VEstimatorDimension>
00139 ::UpdateWithNewMeasure( const ValueType & newMeasure,
00140 const VectorType & newPredictor )
00141 {
00142 ValueType measurePrediction = dot_product( newPredictor , m_Estimator );
00143
00144 ValueType errorMeasurePrediction = newMeasure - measurePrediction;
00145
00146 VectorType Corrector = m_Variance * newPredictor;
00147
00148 for( unsigned int j=0; j<VEstimatorDimension; j++)
00149 {
00150 m_Estimator(j) += Corrector(j) * errorMeasurePrediction;
00151 }
00152
00153 UpdateVariance( newPredictor );
00154
00155 }
00156
00157
00158 template <class T, unsigned int VEstimatorDimension>
00159 void
00160 KalmanLinearEstimator<T,VEstimatorDimension>
00161 ::UpdateVariance( const VectorType & newPredictor )
00162 {
00163 VectorType aux = m_Variance * newPredictor;
00164
00165 ValueType denominator = 1.0/(1.0 + dot_product( aux , newPredictor ) );
00166
00167 for( unsigned int col=0; col<VEstimatorDimension; col++)
00168 {
00169 for( unsigned int row=0; row<VEstimatorDimension; row++)
00170 {
00171 m_Variance(col,row) -= aux(col)*aux(row)*denominator;
00172 }
00173 }
00174 }
00175
00176 }
00177
00178 #endif
00179