提取和匹配线特征的一个demo

一、代码来源： https://github.com/drozdvadym/opencv_line_descriptor

二、依赖包：OpenCV 2.4.9

三、Matching的运行结果截图：

四、代码分析

代码里重要的语句都有注释，在这里只附上代码，并做简要补充。。

下面是LBD，LSD两种方案的主要代码

int main(void argc,const char **argv)
{
...
...
  /* load image */
  cv::Mat imageMat1 = imread( image_path1, 1 );
  cv::Mat imageMat2 = imread( image_path2, 1 );
...
  /* create binary masks */
  //These will be used to when descript line.   
  cv::Mat mask1 = Mat::ones( imageMat1.size(), CV_8UC1 );
  cv::Mat mask2 = Mat::ones( imageMat2.size(), CV_8UC1 );
...
  /* compute lines and descriptors */
  std::vector<KeyLine> keylines1, keylines2;
  cv::Mat descr1, descr2;

  ( *bd )( imageMat1, mask1, keylines1, descr1, false, false );
  ( *bd )( imageMat2, mask2, keylines2, descr2, false, false );
...
  /* select keylines from first octave and their descriptors */
  std::vector<KeyLine> lbd_octave1, lbd_octave2;
  Mat left_lbd, right_lbd;
  for ( int i = 0; i < (int) keylines1.size(); i++ )
  {
    if( keylines1[i].octave == 0 )
    {
      lbd_octave1.push_back( keylines1[i] );
      left_lbd.push_back( descr1.row( i ) );
    }
  }
...
  /* create a BinaryDescriptorMatcher object */
  Ptr<BinaryDescriptorMatcher> bdm = BinaryDescriptorMatcher::createBinaryDescriptorMatcher();

  /* require match */
  std::vector<DMatch> matches;
  bdm->match( left_lbd, right_lbd, matches );

  /* select best matches */
  std::vector<DMatch> good_matches;
  for ( int i = 0; i < (int) matches.size(); i++ )
  {
    if( matches[i].distance < MATCHES_DIST_THRESHOLD )
      good_matches.push_back( matches[i] );
  }
...
//code for image show.
} 

  ...
  /* create an LSD detector */
  Ptr<LSDDetector> lsd = LSDDetector::createLSDDetector();

  /* detect lines */
  std::vector<KeyLine> klsd1, klsd2;
  Mat lsd_descr1, lsd_descr2;
  lsd->detect( imageMat1, klsd1, 2, 2, mask1 );
  lsd->detect( imageMat2, klsd2, 2, 2, mask2 );

  /* compute descriptors for lines from first octave */
  bd->compute( imageMat1, klsd1, lsd_descr1 );
  bd->compute( imageMat2, klsd2, lsd_descr2 );

  //select lines and descriptors
  ...
  /* compute matches */
  std::vector<DMatch> lsd_matches;
  bdm->match( leftDEscr, rightDescr, lsd_matches );
  //select best match
  ...
  //show image with lines feature.
  ...

由于matching.cpp里已包含线特征的提取，所以没有单独运行一下提取线特征的程序。

sample里其他程序的测试以后再添上去吧。