We propose an algorithmic compass that yields the heading information of a mobile robot using the vanishing point in indoor environments: VPass. With the VPass, a loop-closing effect (which is a significant reduction of errors by revisiting a known place through a loop) can be achieved even for a loop-less environment. From the implementation point of view, the VPass is useful because it can be appended upon any existing navigation algorithms. Experimental results show that the VPass yields accurate angle information in indoor environments for paths with lengths of around 200m.
<Fig. 2> Experiment1. Building with a loop: (Left) EKF SLAM Only (Center) Line Based SLAM (Right) VPass + EKF SLAM
<Fig. 3> Experiment2. Building without a loop: (Left) EKF SLAM Only (Center) Line Based SLAM (Right) VPass + EKF SLAM
 Young Hoon Lee, Changjoo Nam, Keon Yong Lee, Yuen Shang Li, Soo Yong Yeon, and Nakju Lett Doh,
VPass: Algorithmic Compass using Vanishing Points in Indoor Environments,
International Conference on Intelligent Robots and Systems (IROS) 2009, pp. 936-941, St. Louis, USA, Oct. 11-15, 2009.