TagDetection.h

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#ifndef TAGDETECTION_H
#define TAGDETECTION_H

#include <Eigen/Dense>

#include "opencv2/opencv.hpp"

#include <utility>
#include <vector>

namespace AprilTags {

struct TagDetection {

  TagDetection();

  TagDetection(int id);

  bool good;

  long long obsCode;

  long long code;

  int id;

  int hammingDistance;
  
  int rotation;

  /*  The points travel counter-clockwise around the target, always
   *  starting from the same corner of the tag.
   */
  std::pair<float,float> p[4];

  std::pair<float,float> cxy;


  float observedPerimeter;

  /*  Both the input and output coordinates are 2D homogeneous vectors, with y = Hx.
   *  'y' are pixel coordinates, 'x' are tag-relative coordinates. Tag coordinates span
   *  from (-1,-1) to (1,1). The orientation of the homography reflects the orientation
   *  of the target.
   */
  Eigen::Matrix3d homography;

  float getXYOrientation() const;

  std::pair<float,float> hxy;

  std::pair<float,float> interpolate(float x, float y) const;

  bool overlapsTooMuch(const TagDetection &other) const;

  /* Returns the relative location and orientation of the tag using a
     4x4 homogeneous transformation matrix (see Hartley&Zisserman,
     Multi-View Geometry, 2003). Requires knowledge of physical tag
     size (side length of black square in meters) as well as camera
     calibration (focal length and principal point); Result is in
     camera frame (z forward, x right, y down)
  */
  Eigen::Matrix4d getRelativeTransform(double tag_size, double fx, double fy,
                                       double px, double py) const;

  // Result is in object frame (x forward, y left, z up)
  void getRelativeTranslationRotation(double tag_size, double fx, double fy, double px, double py,
                                      Eigen::Vector3d& trans, Eigen::Matrix3d& rot) const;

  void draw(cv::Mat& image) const;
};

} // namespace

#endif