CornerDetectorHarris.cpp

/*
This file is part of the BIAS library (Basic ImageAlgorithmS).

Copyright (C) 2003-2009    (see file CONTACT for details)
  Multimediale Systeme der Informationsverarbeitung
  Institut fuer Informatik
  Christian-Albrechts-Universitaet Kiel


BIAS is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

BIAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with BIAS; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "CornerDetectorHarris.hh"

using namespace std;
using namespace BIAS;


//////////////////////////////////////////////////////////////////////////
//                 implementation
//////////////////////////////////////////////////////////////////////////


template <class StorageType, class CalculationType>
CornerDetectorHarris<StorageType, CalculationType>::
CornerDetectorHarris():
CornerDetectorGradient<StorageType,CalculationType>()
{
  _Scale = 0.04;
}

template <class StorageType, class CalculationType>
CornerDetectorHarris<StorageType,CalculationType>::
~CornerDetectorHarris()
{
}

template <class StorageType, class CalculationType> int
CornerDetectorHarris<StorageType, CalculationType>::
_ComputeCornerness(Image<CalculationType>& Cornerness)
{
  // preserver ROI
  int tlx, tly, brx, bry;
  this->_sgxx.GetROI()->GetCorners(tlx, tly, brx, bry);
  Cornerness.GetROI()->SetCorners(tlx, tly, brx, bry);

  const unsigned int minx=tlx;
  const unsigned int miny=tly;
  const unsigned int maxx=brx;
  const unsigned int maxy=bry;

  const unsigned int width=Cornerness.GetWidth();
  //const unsigned int height=Cornerness.GetHeight(); not used

  // work pointers to summed multiplied derivatives
  CalculationType **psgxx=this->_sgxx.GetImageDataArray(),
    **psgyy=this->_sgyy.GetImageDataArray(),
    **psgxy=this->_sgxy.GetImageDataArray();
  CalculationType *ptr, *end, tmp;

  // init min und max with impossible values
  float scale = float ( _Scale );
  // init all pointers to first usable position (skip upper two lines)
  unsigned offs = width*miny;
  unsigned int x=0,y=0;
  ptr = Cornerness.GetImageData()+offs;
  end   = Cornerness.GetImageData()+width*(maxy);
  const double me=(double)this->_MinCornerness;
  Feat fp;
  this->_FeatList.clear();
  this->_FeatList.reserve(end-ptr);
  // run over all pixels, from roi start to end
  for (y=miny; y<maxy; y++){
    for (x=minx; x<maxx; x++){
      const CalculationType xx = (CalculationType)psgxx[y][x];
      const CalculationType xy = (CalculationType)psgxy[y][x];
      const CalculationType yy = (CalculationType)psgyy[y][x];

      //cornerness = det - scale*trace*trace
      tmp = (CalculationType) (xx*yy-xy*xy - scale * (xx+yy) * (xx+yy));

      // save highest/lowest values for quality analysis later
      if (tmp>me){
          fp.x=x;
          fp.y=y;
          fp.val=(tmp>(double)INT_MAX)?(INT_MAX):((int)tmp);
          this->_FeatList.push_back(fp);
          //cout <<"Found a point above min cornerness: "<<endl;
      }
      *ptr++ = tmp;
      if (++x>=width){
          y++;
          x=0;
      }
    }
  }
  return 0;
}

//////////////////////////////////////////////////////////////////////////
//                 instantiation
//////////////////////////////////////////////////////////////////////////
namespace BIAS{
template class CornerDetectorHarris<unsigned char, float>;
template class CornerDetectorHarris<float, float>;

// fill in instances as required
#ifdef BUILD_IMAGE_INT
template class CornerDetectorHarris<unsigned char, int>;
#endif
#ifdef BUILD_IMAGE_CHAR
template class CornerDetectorHarris<unsigned char, char>;
#endif
#ifdef BUILD_IMAGE_SHORT
#endif
#ifdef BUILD_IMAGE_USHORT
template class CornerDetectorHarris<unsigned short, float>;
#ifdef BUILD_IMAGE_INT
template class CornerDetectorHarris<unsigned short, int>;
#endif
#endif
#ifdef BUILD_IMAGE_UINT
#endif
#ifdef BUILD_IMAGE_DOUBLE
#endif
}