Function TriangulationDltTerm

src/colmap/geometry/triangulation.cc:143–148

Contribution of a single bearing observation to the projector-based DLT normal-equation matrix. With unit bearing b and projection matrix P = cam_from_world, the residual operator is term = P - b b^T P, and the system accumulates term^T term.

// P = cam_from_world, the residual operator is term = P - b b^T P, and the
// system accumulates term^T term.
inline Eigen::Matrix4d TriangulationDltTerm(
    const Eigen::Matrix3x4d& cam_from_world, const Eigen::Vector3d& cam_ray) {
  const Eigen::Matrix3x4d term =
      cam_from_world - cam_ray * cam_ray.transpose() * cam_from_world;
  return term.transpose() * term;
}

// Solve the DLT system for the homogeneous point (smallest eigenvector of A).
inline bool SolveTriangulationDlt(const Eigen::Matrix4d& A,