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Add the ensureSimpleDistance() method to ensure the user the returned distance is not ^2 (the default for L2 for instance)

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Pierre-Emmanuel Viel 2014-05-21 13:16:12 +02:00
parent 976da2f3d3
commit ec99f96c62
1 changed files with 60 additions and 0 deletions
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60
modules/flann/include/opencv2/flann/dist.h
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@ -872,6 +872,66 @@ typename Distance::ResultType ensureSquareDistance( typename Distance::ResultTyp
return dummy( dist );
}
/*
* ...and a template to ensure the user that he will process the normal distance,
* and not squared distance, without loosing processing time calling sqrt(ensureSquareDistance)
* that will result in doing actually sqrt(dist*dist) for L1 distance for instance.
*/
template <typename Distance, typename ElementType>
struct simpleDistance
{
typedef typename Distance::ResultType ResultType;
ResultType operator()( ResultType dist ) { return dist; }
};
template <typename ElementType>
struct simpleDistance<L2_Simple<ElementType>, ElementType>
{
typedef typename L2_Simple<ElementType>::ResultType ResultType;
ResultType operator()( ResultType dist ) { return sqrt(dist); }
};
template <typename ElementType>
struct simpleDistance<L2<ElementType>, ElementType>
{
typedef typename L2<ElementType>::ResultType ResultType;
ResultType operator()( ResultType dist ) { return sqrt(dist); }
};
template <typename ElementType>
struct simpleDistance<MinkowskiDistance<ElementType>, ElementType>
{
typedef typename MinkowskiDistance<ElementType>::ResultType ResultType;
ResultType operator()( ResultType dist ) { return sqrt(dist); }
};
template <typename ElementType>
struct simpleDistance<HellingerDistance<ElementType>, ElementType>
{
typedef typename HellingerDistance<ElementType>::ResultType ResultType;
ResultType operator()( ResultType dist ) { return sqrt(dist); }
};
template <typename ElementType>
struct simpleDistance<ChiSquareDistance<ElementType>, ElementType>
{
typedef typename ChiSquareDistance<ElementType>::ResultType ResultType;
ResultType operator()( ResultType dist ) { return sqrt(dist); }
};
template <typename Distance>
typename Distance::ResultType ensureSimpleDistance( typename Distance::ResultType dist )
{
typedef typename Distance::ElementType ElementType;
simpleDistance<Distance, ElementType> dummy;
return dummy( dist );
}
}
#endif //OPENCV_FLANN_DIST_H_