Undelayed initialization of line segments in monocular SLAM

This paper presents 6-DOF monocular EKF-SLAM with undelayed initialization using linear landmarks with extensible endpoints, based on the Plu¿cker parametrization. A careful analysis of the properties of the Plu¿cker coordinates, defined in the projective space P⁵, permits their direct usage for undelayed initialization. Immediately after detection of a segment in the image, a Plu¿cker line is incorporated in the map. A single Gaussian pdf includes inside its 2-sigma region all possible lines given the observed segment, from arbitrarily close up to the infinity range, and in any orientation. The lines converge to stable 3D configurations as the moving camera gathers observations from new viewpoints. The line´s endpoints, maintained out of the map, are constantly retro-projected from the image onto the line´s local reference frame. An extending-only policy is defined to update them. We validate the method via Monte Carlo simulations and with real imagery data.