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added SL2 (squared L2 distance) and implemented the descriptors matching in L2 using SL2

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This commit is contained in:
Maria Dimashova 2011-08-08 13:18:12 +00:00
parent a9fdc1bdff
commit fcd999ae6e
3 changed files with 142 additions and 71 deletions
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16
modules/features2d/doc/common_interfaces_of_descriptor_matchers.rst
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@ -301,6 +301,20 @@ For efficiency, ``BruteForceMatcher`` is used as a template parameterized with t
ResultType operator()( const T* a, const T* b, int size ) const;
};
/*
* Squared Euclidean distance functor
*/
template<class T>
struct SL2
{
typedef T ValueType;
typedef typename Accumulator<T>::Type ResultType;
ResultType operator()( const T* a, const T* b, int size ) const;
};
// Note: in case of SL2 distance a parameter maxDistance in the method DescriptorMatcher::radiusMatch
// is a squared maximum distance in L2.
/*
* Manhattan distance (city block distance) functor
*/
@ -311,7 +325,6 @@ For efficiency, ``BruteForceMatcher`` is used as a template parameterized with t
typedef typename Accumulator<T>::Type ResultType;
ResultType operator()( const T* a, const T* b, int size ) const;
...
};
/*
@ -334,7 +347,6 @@ For efficiency, ``BruteForceMatcher`` is used as a template parameterized with t
ResultType operator()( const unsigned char* a, const unsigned char* b,
int size ) const;
...
};

21
modules/features2d/include/opencv2/features2d/features2d.hpp
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@ -2083,6 +2083,27 @@ template<> struct Accumulator<unsigned short> { typedef float Type; };
template<> struct Accumulator<char> { typedef float Type; };
template<> struct Accumulator<short> { typedef float Type; };
/*
* Squeared Euclidean distance functor
*/
template<class T>
struct CV_EXPORTS SL2
{
typedef T ValueType;
typedef typename Accumulator<T>::Type ResultType;
ResultType operator()( const T* a, const T* b, int size ) const
{
ResultType result = ResultType();
for( int i = 0; i < size; i++ )
{
ResultType diff = (ResultType)(a[i] - b[i]);
result += diff*diff;
}
return result;
}
};
/*
* Euclidean distance functor
*/

48
modules/features2d/src/matchers.cpp
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@ -328,6 +328,10 @@ Ptr<DescriptorMatcher> DescriptorMatcher::create( const string& descriptorMatche
{
dm = new BruteForceMatcher<L2<float> >();
}
else if( !descriptorMatcherType.compare( "BruteForce-SL2" ) ) // Squared L2
{
dm = new BruteForceMatcher<SL2<float> >();
}
else if( !descriptorMatcherType.compare( "BruteForce-L1" ) )
{
dm = new BruteForceMatcher<L1<float> >();
@ -345,10 +349,10 @@ Ptr<DescriptorMatcher> DescriptorMatcher::create( const string& descriptorMatche
}
/*
* BruteForce L2 specialization
* BruteForce SL2 and L2 specialization
*/
template<>
void BruteForceMatcher<L2<float> >::knnMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, int knn,
void BruteForceMatcher<SL2<float> >::knnMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, int knn,
const vector<Mat>& masks, bool compactResult )
{
#ifndef HAVE_EIGEN
@ -427,7 +431,7 @@ void BruteForceMatcher<L2<float> >::knnMatchImpl( const Mat& queryDescriptors, v
break;
e_allDists[bestImgIdx](bestTrainIdx) = -std::numeric_limits<float>::max();
curMatches->push_back( DMatch(qIdx, bestTrainIdx, bestImgIdx, sqrt((-2)*totalMaxCoeff + queryNorm2)) );
curMatches->push_back( DMatch(qIdx, bestTrainIdx, bestImgIdx, (-2)*totalMaxCoeff + queryNorm2) );
}
std::sort( curMatches->begin(), curMatches->end() );
}
@ -436,7 +440,7 @@ void BruteForceMatcher<L2<float> >::knnMatchImpl( const Mat& queryDescriptors, v
}
template<>
void BruteForceMatcher<L2<float> >::radiusMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, float maxDistance,
void BruteForceMatcher<SL2<float> >::radiusMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, float maxDistance,
const vector<Mat>& masks, bool compactResult )
{
#ifndef HAVE_EIGEN
@ -492,7 +496,7 @@ void BruteForceMatcher<L2<float> >::radiusMatchImpl( const Mat& queryDescriptors
{
if( masks.empty() || isPossibleMatch(masks[iIdx], qIdx, tIdx) )
{
float d = sqrt((-2)*e_allDists[iIdx](tIdx) + queryNorm2);
float d = (-2)*e_allDists[iIdx](tIdx) + queryNorm2;
if( d < maxDistance )
curMatches->push_back( DMatch( qIdx, tIdx, iIdx, d ) );
}
@ -504,6 +508,40 @@ void BruteForceMatcher<L2<float> >::radiusMatchImpl( const Mat& queryDescriptors
#endif
}
inline void sqrtDistance( vector<vector<DMatch> >& matches )
{
for( size_t imgIdx = 0; imgIdx < matches.size(); imgIdx++ )
{
for( size_t matchIdx = 0; matchIdx < matches[imgIdx].size(); matchIdx++ )
{
matches[imgIdx][matchIdx].distance = std::sqrt( matches[imgIdx][matchIdx].distance );
}
}
}
template<>
void BruteForceMatcher<L2<float> >::knnMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, int knn,
const vector<Mat>& masks, bool compactResult )
{
BruteForceMatcher<SL2<float> > matcherSL2;
matcherSL2.add( getTrainDescriptors() );
matcherSL2.knnMatch( queryDescriptors, matches, knn, masks, compactResult );
sqrtDistance( matches );
}
template<>
void BruteForceMatcher<L2<float> >::radiusMatchImpl( const Mat& queryDescriptors, vector<vector<DMatch> >& matches, float maxDistance,
const vector<Mat>& masks, bool compactResult )
{
const float maxDistance2 = maxDistance * maxDistance;
BruteForceMatcher<SL2<float> > matcherSL2;
matcherSL2.add( getTrainDescriptors() );
matcherSL2.radiusMatch( queryDescriptors, matches, maxDistance2, masks, compactResult );
sqrtDistance( matches );
}
/*
* Flann based matcher
*/