ipoint.cpp

/*********************************************************** 
*  --- OpenSURF ---                                       *
*  This library is distributed under the GNU GPL. Please   *
*  use the contact form at http://www.chrisevansdev.com    *
*  for more information.                                   *
*                                                          *
*  C. Evans, Research Into Robust Visual Features,         *
*  MSc University of Bristol, 2008.                        *
*                                                          *
************************************************************/

#include <opencv/cv.h>
#include <vector>

#include "ipoint.h"

//! Populate IpPairVec with matched ipts 
void getMatches(IpVec &ipts1, IpVec &ipts2, IpPairVec &matches)
{
  float dist, d1, d2;
  Ipoint *match;

  matches.clear();

  for(unsigned int i = 0; i < ipts1.size(); i++) 
  {
    d1 = d2 = FLT_MAX;

    for(unsigned int j = 0; j < ipts2.size(); j++) 
    {
      dist = ipts1[i] - ipts2[j];  

      if(dist<d1) // if this feature matches better than current best
      {
        d2 = d1;
        d1 = dist;
        match = &ipts2[j];
      }
      else if(dist<d2) // this feature matches better than second best
      {
        d2 = dist;
      }
    }

    // If match has a d1:d2 ratio < 0.65 ipoints are a match
    if(d1/d2 < 0.65) 
    { 
      // Store the change in position
      ipts1[i].dx = match->x - ipts1[i].x; 
      ipts1[i].dy = match->y - ipts1[i].y;
      matches.push_back(std::make_pair(ipts1[i], *match));
    }
  }
}

//
// This function uses homography with CV_RANSAC (OpenCV 1.1)
// Won't compile on most linux distributions
//

//-------------------------------------------------------

////! Find homography between matched points and translate src_corners to dst_corners
int translateCorners(IpPairVec &matches, const CvPoint src_corners[4], CvPoint dst_corners[4])
{
//#ifndef LINUX
//  double h[9];
//  CvMat _h = cvMat(3, 3, CV_64F, h);
//  std::vector<CvPoint2D32f> pt1, pt2;
//  CvMat _pt1, _pt2;
  
//  int n = (int)matches.size();
//  if( n < 4 ) return 0;

//  // Set vectors to correct size
//  pt1.resize(n);
//  pt2.resize(n);

//  // Copy Ipoints from match vector into cvPoint vectors
//  for(int i = 0; i < n; i++ )
//  {
//    pt1[i] = cvPoint2D32f(matches[i].second.x, matches[i].second.y);
//    pt2[i] = cvPoint2D32f(matches[i].first.x, matches[i].first.y);
//  }
//  _pt1 = cv::Mat(1, n, CV_32FC2, &pt1[0] );
//  _pt2 = cv::Mat(1, n, CV_32FC2, &pt2[0] );

//  // Find the homography (transformation) between the two sets of points
//  _h = cv::findHomography(cv::Mat(&_pt1),cv::Mat(&_pt2),cv::RANSAC,5);
//  //  if(!cv::findHomography(cvFindHomography(&_pt1, &_pt2, &_h, CV_RANSAC, 5))  // this line requires opencv 1.1
////    return 0;

//  // Translate src_corners to dst_corners using homography
//  for(int i = 0; i < 4; i++ )
//  {
//    double x = src_corners[i].x, y = src_corners[i].y;
//    double Z = 1./(h[6]*x + h[7]*y + h[8]);
//    double X = (h[0]*x + h[1]*y + h[2])*Z;
//    double Y = (h[3]*x + h[4]*y + h[5])*Z;
//    dst_corners[i] = cvPoint(cvRound(X), cvRound(Y));
//  }
//#endif
  return 1;
}