Impala Documentation

template<class ArrayT>

ArrayT* Impala::Core::Matrix::MatMahalanobis	(	ArrayT *	a,
		ArrayT *	b,
		ArrayT *	c
	)			`[inline]`

Mahalanobis distance.

Definition at line 18 of file MatMahalanobis.h.

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

00019 {
00020     typedef typename ArrayT::ArithType ArithT;
00021     typedef typename ArrayT::StorType StorT;
00022 
00023     int nr = MatNrRow(a);
00024     int nc = MatNrCol(b);
00025     ArrayT* m = MatCreate<ArrayT>(nr, nc);
00026     MatSet(m, 0);
00027 
00028     for (int i=0 ; i<nr ; i++)   //for each pixel
00029     {
00030         StorT* miPtr = MatE(m, i, 0);
00031         StorT* aiPtr = MatE(a, i, 0);
00032         for (int j=0 ; j<nc ; j++)   //for each concept
00033         {
00034             double sum = 0;
00035             for (int k=0 ; k<MatNrCol(a) ; k++) //for each filter
00036             {
00037                 double ckj = *MatE(c, k, j);
00038                 double bkj = *MatE(b, k, j);
00039                 if (ckj > 0)  //is this correct?
00040                 {
00041                     sum += ( (aiPtr[k] - bkj) * (aiPtr[k] - bkj) ) / (ckj*ckj);
00042                 }
00043             }   
00044             miPtr[j] = sqrt( sum ); 
00045         }
00046     }
00047     return m;
00048 }

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