opencv/modules/features2d/src/detectors.cpp

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#include "precomp.hpp"

using namespace std;
using namespace cv;

/*
    FeatureDetector
*/
struct MaskPredicate
{
    MaskPredicate( const Mat& _mask ) : mask(_mask)
    {}
    MaskPredicate& operator=(const MaskPredicate&) {}
    bool operator() (const KeyPoint& key_pt) const
    {
      return mask.at<uchar>( (int)(key_pt.pt.y + 0.5f), (int)(key_pt.pt.x + 0.5f) ) != 0;
    }

    const Mat& mask;
};

void FeatureDetector::removeInvalidPoints( const Mat& mask, vector<KeyPoint>& keypoints )
{
    if( mask.empty() )
        return;

    keypoints.erase(remove_if(keypoints.begin(), keypoints.end(), MaskPredicate(mask)), keypoints.end());
};

/*
    FastFeatureDetector
*/
FastFeatureDetector::FastFeatureDetector( int _threshold, bool _nonmaxSuppression )
  : threshold(_threshold), nonmaxSuppression(_nonmaxSuppression)
{}

void FastFeatureDetector::detectImpl( const Mat& image, const Mat& mask, vector<KeyPoint>& keypoints) const
{
    FAST( image, keypoints, threshold, nonmaxSuppression );
    removeInvalidPoints( mask, keypoints );
}

/*
    GoodFeaturesToTrackDetector
*/
GoodFeaturesToTrackDetector::GoodFeaturesToTrackDetector( int _maxCorners, double _qualityLevel, \
                                                          double _minDistance, int _blockSize,
                                                          bool _useHarrisDetector, double _k )
    : maxCorners(_maxCorners), qualityLevel(_qualityLevel), minDistance(_minDistance),
      blockSize(_blockSize), useHarrisDetector(_useHarrisDetector), k(_k)
{}

void GoodFeaturesToTrackDetector::detectImpl( const Mat& image, const Mat& mask,
                                              vector<KeyPoint>& keypoints ) const
{
    vector<Point2f> corners;
    goodFeaturesToTrack( image, corners, maxCorners, qualityLevel, minDistance, mask,
                         blockSize, useHarrisDetector, k );
    keypoints.resize(corners.size());
    vector<Point2f>::const_iterator corner_it = corners.begin();
    vector<KeyPoint>::iterator keypoint_it = keypoints.begin();
    for( ; corner_it != corners.end(); ++corner_it, ++keypoint_it )
    {
        *keypoint_it = KeyPoint( *corner_it, 1.f );
    }
}

/*
    MserFeatureDetector
*/
MserFeatureDetector::MserFeatureDetector( int delta, int minArea, int maxArea,
                                          float maxVariation, float minDiversity,
                                          int maxEvolution, double areaThreshold,
                                          double minMargin, int edgeBlurSize )
  : mser( delta, minArea, maxArea, maxVariation, minDiversity,
          maxEvolution, areaThreshold, minMargin, edgeBlurSize )
{}

void MserFeatureDetector::detectImpl( const Mat& image, const Mat& mask, vector<KeyPoint>& keypoints ) const
{
    vector<vector<Point> > msers;
    mser(image, msers, mask);

    keypoints.resize( msers.size() );
    vector<vector<Point> >::const_iterator contour_it = msers.begin();
    vector<KeyPoint>::iterator keypoint_it = keypoints.begin();
    for( ; contour_it != msers.end(); ++contour_it, ++keypoint_it )
    {
        RotatedRect rect = fitEllipse(Mat(*contour_it));
        *keypoint_it = KeyPoint( rect.center, min(rect.size.height, rect.size.width), rect.angle);
    }
}

/*
    StarFeatureDetector
*/
StarFeatureDetector::StarFeatureDetector(int maxSize, int responseThreshold,
                                         int lineThresholdProjected,
                                         int lineThresholdBinarized,
                                         int suppressNonmaxSize)
  : star( maxSize, responseThreshold, lineThresholdProjected,
          lineThresholdBinarized, suppressNonmaxSize)
{}

void StarFeatureDetector::detectImpl( const Mat& image, const Mat& mask, vector<KeyPoint>& keypoints) const
{
    star(image, keypoints);
    removeInvalidPoints(mask, keypoints);
}

/*
    SiftFeatureDetector
*/
SiftFeatureDetector::SiftFeatureDetector(double threshold, double edgeThreshold,
                                         int nOctaves, int nOctaveLayers, int firstOctave, int angleMode) :
    sift(threshold, edgeThreshold, nOctaves, nOctaveLayers, firstOctave, angleMode)
{
}

void SiftFeatureDetector::detectImpl( const Mat& image, const Mat& mask,
                                      vector<KeyPoint>& keypoints) const
{
    sift(image, mask, keypoints);
}

/*
    SurfFeatureDetector
*/
SurfFeatureDetector::SurfFeatureDetector( double hessianThreshold, int octaves, int octaveLayers)
    : surf(hessianThreshold, octaves, octaveLayers)
{}

void SurfFeatureDetector::detectImpl( const Mat& image, const Mat& mask,
                                      vector<KeyPoint>& keypoints) const
{
    surf(image, mask, keypoints);
}