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itkCoxDeBoorBSplineKernelFunction.h

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00001 /*=========================================================================
00002 
00003   Program:   Insight Segmentation & Registration Toolkit
00004   Module:    $RCSfile: itkCoxDeBoorBSplineKernelFunction.h,v $
00005   Language:  C++
00006   Date:      $Date: 2009-04-23 03:43:41 $
00007   Version:   $Revision: 1.4 $
00008 
00009   Copyright (c) Insight Software Consortium. All rights reserved.
00010   See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
00011 
00012      This software is distributed WITHOUT ANY WARRANTY; without even
00013      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
00014      PURPOSE.  See the above copyright notices for more information.
00015 
00016 =========================================================================*/
00017 #ifndef __itkCoxDeBoorBSplineKernelFunction_h
00018 #define __itkCoxDeBoorBSplineKernelFunction_h
00019 
00020 #include "itkKernelFunction.h"
00021 #include "itkNumericTraits.h"
00022 #include "vnl/vnl_math.h"
00023 #include "vnl/vnl_real_polynomial.h"
00024 #include "vnl/vnl_matrix.h"
00025 
00026 namespace itk
00027 {
00028 
00056 template <unsigned int VSplineOrder = 3>
00057 class ITK_EXPORT CoxDeBoorBSplineKernelFunction
00058 : public KernelFunction
00059 {
00060 public:
00062   typedef CoxDeBoorBSplineKernelFunction        Self;
00063   typedef KernelFunction                        Superclass;
00064   typedef SmartPointer<Self>                    Pointer;
00065   typedef SmartPointer<const Self>              ConstPointer;
00066 
00068   itkNewMacro(Self);
00069 
00071   itkTypeMacro( CoxDeBoorBSplineKernelFunction, KernelFunction );
00072 
00073   typedef double                                RealType;
00074   typedef vnl_vector<RealType>                  VectorType;
00075   typedef vnl_real_polynomial                   PolynomialType;
00076   typedef vnl_matrix<RealType>                  MatrixType;
00077 
00079   void SetSplineOrder( unsigned int );
00080   itkGetConstMacro( SplineOrder, unsigned int );
00082 
00084   inline RealType Evaluate( const RealType & u ) const
00085     {
00086     RealType absValue = vnl_math_abs( u );
00087     unsigned int which;
00088     if( this->m_SplineOrder % 2 == 0 )
00089       {
00090       which = static_cast<unsigned int>( absValue+0.5 );
00091       }
00092     else
00093       {
00094       which = static_cast<unsigned int>( absValue );
00095       }
00096     if( which < this->m_BSplineShapeFunctions.rows() )
00097       {
00098       return PolynomialType(
00099         this->m_BSplineShapeFunctions.get_row( which ) ).evaluate( absValue );
00100       }
00101     else
00102       {
00103       return NumericTraits<RealType>::Zero;
00104       }
00105     }
00107 
00109   inline RealType EvaluateDerivative( const double & u ) const
00110     {
00111     return this->EvaluateNthDerivative( u, 1 );
00112     }
00113 
00115   inline RealType EvaluateNthDerivative( const double & u, unsigned int n ) const
00116     {
00117     RealType absValue = vnl_math_abs( u );
00118     unsigned int which;
00119     if( this->m_SplineOrder % 2 == 0 )
00120       {
00121       which = static_cast<unsigned int>( absValue+0.5 );
00122       }
00123     else
00124       {
00125       which = static_cast<unsigned int>( absValue );
00126       }
00127     if( which < this->m_BSplineShapeFunctions.rows() )
00128       {
00129       PolynomialType polynomial( 
00130         this->m_BSplineShapeFunctions.get_row( which ) );
00131       for( unsigned int i = 0; i < n; i++ )
00132         {
00133         polynomial = polynomial.derivative();
00134         }
00135       RealType der = polynomial.evaluate( absValue );
00136       if( u < NumericTraits<RealType>::Zero && n % 2 != 0 )
00137         {
00138         return -der;
00139         }
00140       else
00141         {
00142         return der;
00143         }
00144       }
00145     else
00146       {
00147       return NumericTraits<RealType>::Zero;
00148       }
00149     }
00151 
00157   MatrixType GetShapeFunctions()
00158     {
00159     return this->m_BSplineShapeFunctions;
00160     }
00161 
00166   MatrixType GetShapeFunctionsInZeroToOneInterval();
00167 
00168 protected:
00169   CoxDeBoorBSplineKernelFunction();
00170   ~CoxDeBoorBSplineKernelFunction();
00171   void PrintSelf( std::ostream& os, Indent indent ) const;
00172 
00173 private:
00174   CoxDeBoorBSplineKernelFunction( const Self& ); //purposely not implemented
00175   void operator=( const Self& ); //purposely not implemented
00176 
00181   void GenerateBSplineShapeFunctions( unsigned int );
00182 
00189   PolynomialType CoxDeBoor( unsigned short, 
00190     VectorType, unsigned int, unsigned int );
00191 
00192   MatrixType    m_BSplineShapeFunctions;
00193   unsigned int  m_SplineOrder;
00194 
00195 };
00196 
00197 } // end namespace itk
00198 
00199 #ifndef ITK_MANUAL_INSTANTIATION
00200 #include "itkCoxDeBoorBSplineKernelFunction.txx"
00201 #endif
00202 
00203 #endif
00204 

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