bilinearInterpolator.h

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00001 
00015 #ifndef DLR_NUMERIC_BILINEARINTERPOLATOR_H
00016 #define DLR_NUMERIC_BILINEARINTERPOLATOR_H
00017 
00018 #include <cmath>
00019 #include <dlrNumeric/array2D.h>
00020 
00021 namespace dlr {
00022 
00023   namespace numeric {
00024     
00025     template <class TYPE>
00026     class BilinearInterpolator
00027     {
00028     public:
00029 
00030       BilinearInterpolator(const Array2D<TYPE>& image0)
00031         : m_array(image0) {}
00032 
00033 
00034       ~BilinearInterpolator() {}
00035 
00036       
00037       inline double
00038       operator()(double row, double column);
00039 
00040     private:
00041 
00042       inline void
00043       checkBounds(double row, double column) const;
00044 
00045     
00046       Array2D<TYPE> m_array;
00047     
00048     };
00049 
00050   } // namespace numeric
00051 
00052 } // namespace dlr
00053 
00054 
00055 /* ======= Declarations to maintain compatibility with legacy code. ======= */
00056 
00057 namespace dlr {
00058 
00059   using numeric::BilinearInterpolator;
00060 
00061 } // namespace dlr
00062 
00063 
00064 namespace dlr {
00065 
00066   namespace numeric {
00067     
00068     template <class TYPE>
00069     inline double
00070     BilinearInterpolator<TYPE>::
00071     operator()(double row, double column)
00072     {
00073       this->checkBounds(row, column);
00074     
00075       double tmpDbl;
00076       double x1 = modf(column, &tmpDbl);
00077       size_t i0 = static_cast<size_t>(tmpDbl);
00078       double y1 = modf(row, &tmpDbl);
00079       size_t j0 = static_cast<size_t>(tmpDbl);
00080       double x0 = 1.0 - x1;
00081       double y0 = 1.0 - y1;
00082       size_t index0 = m_array.columns() * j0 + i0;
00083       return (x0 * (y0 * this->m_array(index0)
00084                     + y1 * this->m_array(index0 + m_array.columns()))
00085               + x1 * (y0 * this->m_array(index0 + 1)
00086                       + y1 * this->m_array(index0 + m_array.columns() + 1)));
00087     }
00088 
00089 
00090     template <class TYPE>
00091     inline void
00092     BilinearInterpolator<TYPE>::
00093     checkBounds(double row, double column) const
00094     {
00095 #ifdef _DLRNUMERIC_CHECKBOUNDS_
00096       int row0 = static_cast<int>(row);
00097       if(row0 < 0 || (row0 + 1) >= static_cast<int>(m_array.rows())) {
00098         std::ostringstream message;
00099         message << "Row index " << row << " is invalid for a(n) "
00100                 << m_array.rows() << " x " << m_array.columns() << " array.";
00101         DLR_THROW(IndexException, "BilinearInterpolator::checkBounds()",
00102                   message.str().c_str());
00103       }
00104       int column0 = static_cast<int>(column);
00105       if(column0 < 0 || (column0 + 1) >= static_cast<int>(m_array.columns())) {
00106         std::ostringstream message;
00107         message << "Column index " << column << " is invalid for a(n) "
00108                 << m_array.rows() << " x " << m_array.columns() << " array.";
00109         DLR_THROW(IndexException, "BilinearInterpolator::checkBounds()",
00110                   message.str().c_str());
00111       }
00112 #endif
00113     }
00114 
00115   } // namespace numeric
00116 
00117 } // namespace dlr
00118 
00119 #endif /* #ifndef DLR_NUMERIC_BILINEARINTERPOLATOR_H */