feature_tracker.h

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#ifndef feature_tracker_h_DEFINED
#define feature_tracker_h_DEFINED

// OpenCV
#include <opencv2/core/core.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <opencv2/nonfree/features2d.hpp>
// STL
#include <vector>
#include <deque>
#include <cpl_visual_features/motion/flow_types.h>
#include <utility>

namespace cpl_visual_features
{

typedef std::vector<float> Descriptor;
typedef std::vector<Descriptor> Descriptors;
typedef std::vector<cv::KeyPoint> KeyPoints;

class FeatureTracker
{
 public:
  FeatureTracker(std::string name, double hessian_thresh=250, int num_octaves=4,
                 int num_layers=2, bool extended=true, bool upright=false,
                 bool use_fast=false);

  //
  // Main tracking logic functions
  //

  void initTracks(cv::Mat& frame);

  AffineFlowMeasures updateTracksLK(cv::Mat& cur_frame, cv::Mat& prev_frame);

  AffineFlowMeasures updateTracks(const cv::Mat& frame);

  AffineFlowMeasures updateTracks(const cv::Mat& frame, const cv::Mat& mask);

  //
  // Feature Matching Functions
  //
 protected:
  /*
   * SSD
   *
   * @short Computes the squareroot of squared differences
   * @param a First descriptor
   * @param b second descriptor
   * @return value of squareroot of squared differences
   */
  double SSD(Descriptor& a, Descriptor& b);

  /*
   * ratioTest
   *
   * @short Computes the  ratio test described in Lowe 2004
   * @param a Descriptor from the first image to compare
   * @param bList List of descriptors from the second image
   * @param threshold Threshold value for ratioTest comparison
   *
   * @return index of the best match, -1 if no match ratio is less than threshold
   */
  std::pair<int, float> ratioTest(Descriptor& a, std::vector<Descriptor>& bList,
                                  double threshold);

  void findMatches(Descriptors& descriptors1, Descriptors& descriptors2,
                   std::vector<int>& matches1, std::vector<int>& matches2,
                   std::vector<float>& scores);

  //
  // Helper Functions
  //

  void updateCurrentDescriptors(const cv::Mat& frame, const cv::Mat& mask);

 public:
  //
  // Getters & Setters
  //

  bool isInitialized() const
  {
    return initialized_;
  }

  void setMinFlowThresh(int min_thresh)
  {
    min_flow_thresh_= min_thresh;
  }

  void setKLTCornerThresh(double corner_thresh)
  {
    klt_corner_thresh_ = corner_thresh;
  }

  void setKLTCornerMinDist(double min_dist)
  {
    klt_corner_min_dist_ = min_dist;
  }

  void setKLTMaxCorners(int max_corners)
  {
    max_corners_ = max_corners;
  }

  void setUseFast(bool use_fast)
  {
    use_fast_ = use_fast;
  }
  void stop() { initialized_ = false; }

  AffineFlowMeasures getMostRecentFlow() const
  {
    return cur_flow_;
  }

  Descriptors getMostRecentDescriptors() const
  {
    return cur_descriptors_;
  }

  KeyPoints getMostRecentKeyPoints() const
  {
    return cur_keypoints_;
  }

  std::vector<float> getMostRecentScores() const
  {
    return cur_scores_;
  }

 public:
  cv::SURF surf_;
 protected:
  KeyPoints prev_keypoints_;
  KeyPoints cur_keypoints_;
  Descriptors prev_descriptors_;
  Descriptors cur_descriptors_;
  AffineFlowMeasures cur_flow_;
  std::vector<float> cur_scores_;
  bool initialized_;
  double ratio_threshold_;
  std::string window_name_;
  int min_flow_thresh_;
  int max_corners_;
  double klt_corner_thresh_;
  double klt_corner_min_dist_;
  bool use_fast_;
};
}
#endif // feature_tracker_h_DEFINED