ground_truth.h

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* Copyright 2008-2009  Marius Muja (mariusm@cs.ubc.ca). All rights reserved.





* Copyright 2008-2009  David G. Lowe (lowe@cs.ubc.ca). All rights reserved.





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#ifndef OPENCV_FLANN_GROUND_TRUTH_H_




#define OPENCV_FLANN_GROUND_TRUTH_H_












#include "dist.h"




#include "matrix.h"












namespace
cvflann


{







template
<typename
Distance>



void
find_nearest(const
Matrix<typename Distance::ElementType>& dataset,
typename
Distance::ElementType* query,
int* matches,
int
nn,



int
skip = 0, Distance distance = Distance())


{



typedef
typename
Distance::ResultType DistanceType;



int
n = nn + skip;







std::vector<int> match(n);



std::vector<DistanceType> dists(n);







dists[0] = distance(dataset[0], query, dataset.cols);



match[0] = 0;



int
dcnt = 1;







for
(size_t
i=1; i<dataset.rows; ++i) {



DistanceType tmp = distance(dataset[i], query, dataset.cols);







if
(dcnt<n) {



match[dcnt] = (int)i;



dists[dcnt++] = tmp;



}



else
if
(tmp < dists[dcnt-1]) {



dists[dcnt-1] = tmp;



match[dcnt-1] = (int)i;



}







int
j = dcnt-1;



// bubble up




while
(j>=1 && dists[j]<dists[j-1]) {



std::swap(dists[j],dists[j-1]);



std::swap(match[j],match[j-1]);



j--;



}



}







for
(int
i=0; i<nn; ++i) {



matches[i] = match[i+skip];



}


}











template
<typename
Distance>



void
compute_ground_truth(const
Matrix<typename Distance::ElementType>& dataset,
const
Matrix<typename Distance::ElementType>& testset, Matrix<int>& matches,



int
skip=0, Distance d = Distance())


{



for
(size_t
i=0; i<testset.rows; ++i) {



find_nearest<Distance>(dataset, testset[i], matches[i], (int)matches.cols, skip, d);



}


}










}











#endif

//OPENCV_FLANN_GROUND_TRUTH_H_