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replaced KeyPoint::overlap implementation by faster version (thanks to Suat Gedikli)

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Maria Dimashova 2010-07-30 14:21:55 +00:00
parent 8f8aba9c88
commit 5e84ab0222
1 changed files with 27 additions and 34 deletions
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61
modules/features2d/src/keypoint.cpp
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@ -111,48 +111,41 @@ void KeyPoint::convert( const std::vector<Point2f>& points2f, std::vector<KeyPoi
float KeyPoint::overlap( const KeyPoint& kp1, const KeyPoint& kp2 )
{
const int seedsPerDim = 50;
float a = kp1.size * 0.5f;
float b = kp2.size * 0.5f;
float a_2 = a * a;
float b_2 = b * b;
float radius1 = kp1.size/2;
float radius2 = kp2.size/2;
float radius1_2 = radius1*radius1,
radius2_2 = radius2*radius2;
Point2f p1 = kp1.pt, p2 = kp2.pt;
float dist = norm(p1-p2);
Point2f p1 = kp1.pt;
Point2f p2 = kp2.pt;
float c = norm( p1 - p2 );
float ovrl = 0.f;
if( dist < radius1+radius2 ) // circles are intersected
// one circle is completely encovered by the other => no intersection points!
if( min( a, b ) + c <= max( a, b ) )
return min( a_2, b_2 ) / max( a_2, b_2 );
if( c < a + b ) // circles intersect
{
float minx = min( p1.x - radius1, p2.x - radius2 );
float maxx = max( p1.x + radius1, p2.x + radius2 );
float miny = min( p1.y - radius1, p2.y - radius2 );
float maxy = max( p1.y + radius1, p2.y + radius2 );
float c_2 = c * c;
float cosAlpha = ( b_2 + c_2 - a_2 ) / ( kp2.size * c );
float cosBeta = ( a_2 + c_2 - b_2 ) / ( kp1.size * c );
float alpha = acos( cosAlpha );
float beta = acos( cosBeta );
float sinAlpha = sin(alpha);
float sinBeta = sin(beta);
float mina = (maxx-minx) < (maxy-miny) ? (maxx-minx) : (maxy-miny);
float step = mina/seedsPerDim;
float bua = 0, bna = 0;
float segmentAreaA = a_2 * beta;
float segmentAreaB = b_2 * alpha;
//compute the areas
for( float x = minx; x <= maxx; x+=step )
{
for( float y = miny; y <= maxy; y+=step )
{
float rx1 = x-p1.x;
float ry1 = y-p1.y;
float rx2 = x-p2.x;
float ry2 = y-p2.y;
float triangleAreaA = a_2 * sinBeta * cosBeta;
float triangleAreaB = b_2 * sinAlpha * cosAlpha;
//substitution in the equation of a circle
float c1 = rx1*rx1+ry1*ry1;
float c2 = rx2*rx2+ry2*ry2;
float intersectionArea = segmentAreaA + segmentAreaB - triangleAreaA - triangleAreaB;
float unionArea = (a_2 + b_2) * M_PI - intersectionArea;
if( c1<radius1_2 && c2<radius2_2 ) bna++;
if( c1<radius1_2 || c2<radius2_2 ) bua++;
}
}
if( bna > 0)
ovrl = bna/bua;
ovrl = intersectionArea / unionArea;
}
return ovrl;