Impala Documentation

template<class ArrayT>

void Impala::Core::Matrix::MatFeatureNormalization ( ArrayT * m ) [inline]

Definition at line 16 of file MatFeatureNormalization.h.

References MatE(), MatNrCol(), MatNrRow(), MatSet(), and VecE().

Referenced by Impala::Core::Array::ColorSegmentation().

00017 {
00018     typedef typename ArrayT::ArithType ArithT;
00019     typedef typename ArrayT::StorType StorT;
00020 
00021     int nRow = MatNrRow(m);
00022     int nCol = MatNrCol(m);
00023     ArrayT* M = VecCreate<ArrayT>(nCol); //means
00024     ArrayT* S = VecCreate<ArrayT>(nCol); //variances 
00025 
00026     MatSet(M, 0);
00027     MatSet(S, 0);
00028 
00029     StorT* MPtr = VecE(M, 0);
00030     StorT* SPtr = VecE(S, 0);
00031     for (int i=0 ; i<nRow ; i++)
00032     {
00033         StorT* miPtr = MatE(m, i, 0);
00034         for (int j=0 ; j<nCol ; j++)
00035         {
00036             ArithT x = miPtr[j];
00037             MPtr[j] += x;
00038             SPtr[j] += x*x;
00039         }
00040     }
00041 
00042     for (int j=0 ; j<nCol ; j++)
00043     {
00044         ArithT mj = MPtr[j]/nRow;
00045         SPtr[j] = sqrt( SPtr[j]/nRow - mj * mj );
00046     }
00047 
00048     //normalize
00049     for (int k=0 ; k<nRow; k++)
00050     {
00051         StorT* mkPtr = MatE(m, k, 0);
00052         for (int j=0 ; j<nCol ; j++)
00053             mkPtr[j] = mkPtr[j] / SPtr[j];
00054     }
00055 
00056     delete M;
00057     delete S;
00058 }

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