Peter Kohlhepp Georg Bretthauer Marcus Walther Rüdiger Dillmann Using Orthogonal Surface Directions for Autonomous 3D-Exploration of Indoor Environments. 3086-3092 2006 IROS http://dx.doi.org/10.1109/IROS.2006.282326 conf/iros/2006 db/conf/iros/iros2006.html#KohlheppBWD06