Real-time obstacle detection and avoidance in the presence of specular surfaces using an active 3D sensor

This paper proposes a novel approach to obstacle detection and avoidance using a 3D sensor. We depart from the approach of previous researchers who use depth images from 3D sensors projected onto UV-disparity to detect obstacles. Instead, our approach relies on projecting 3D points onto the ground plane, which is estimated during a calibration step. A 2D occupancy map is then used to determine the presence of obstacles, from which translation and rotation velocities are computed to avoid the obstacles. Two innovations are introduced to overcome the limitations of the sensor: An infinite pole approach is proposed to hypothesize infinitely tall, thin obstacles when the sensor yields invalid readings, and a control strategy is adopted to turn the robot away from scenes that yield a high percentage of invalid readings. Together, these extensions enable the system to overcome the inherent limitations of the sensor. Experiments in a variety of environments, including dynamic objects, obstacles of varying heights, and dimly-lit conditions, show the ability of the system to perform robust obstacle avoidance in real time under realistic indoor conditions.