In order for an unmanned vehicle (UV) to safely navigate through its course, it must be capable of detecting and avoiding obstacles in its path.  From a single camera on the vehicle, the 3D structure of its surrounding environment, including any obstacles, can be estimated from motion parallax using a technique called structure from motion.  We present a novel method for calculating structure from motion that does not require a precise calculation of optical flow at each feature point. 

     Another approach we developed for autonomous vehicle to avoid obstacle is using focus of expansion to calculate time-to-impact.  Feature points are detected and a statistically analysis of their distribution change helps determine time-to-impact.  This approach does not require accurate feature tracking and is suitable for the ground vehicle traveling on a planar surface.  We implemented this algorithm in an FPGA system. 

 Graduate Students:

  Jonathan Anderson, Barrett Edwards, Wade Fife, and Paul Merrell

1. A.W. Dennis, J.K. Archibald, B.B. Edwards, and D. J. Lee, “On-Board Vision-Based See and Avoid for Small UAVs,” AIAA Guidance, Navigation, and Control Conference, Honolulu, HI, USA, August 18-21, 2008.

2. B.B. Edwards, W.S. Fife, J.K. Archibald, D.J. Lee, and D.K. Wilde, "A Design Approach for Small Vision-based Autonomous Vehicles,” SPIE Optics East, Intelligent Robots and Computer Vision XXIV: Algorithms, Techniques, and Active Vision, vol. 6384, 63840L, Boston, MA, USA October. 3-4, 2006.

3. J.D. Anderson, D.J. Lee, and J.K. Archibald, “Hardware Implementation of Feature Density Distribution Algorithm for Autonomous Robot,” Proceedings of The 31st Annual Conference of the IEEE Industrial Electronics Society (IECON), p. 357-362, Raleigh, NC, USA, November 6-10, 2005.

4. P.C. Merrell, D.J. Lee, and R.W. Beard, “Obstacle Avoidance for Unmanned Air Vehicles Using Optical Flow Probability Distributions”, SPIE Optics East, Robotics Technologies and Architectures, Mobile Robot XVII, vol. 5609-04, p. 13-22, Philadelphia, PA, USA, October 25-28, 2004.

5. D.J. Lee, R.W. Beard, P.C. Merrell, and P. Zhan, “See and Avoidance Behaviors for Autonomous Navigation”, SPIE Optics East, Robotics Technologies and Architectures, Mobile Robot XVII, vol. 5609-05, p. 23-34, Philadelphia, PA, USA, October 25-28, 2004.

6. P. Merrell, D.J. Lee, and R.W. Beard, “Statistical Analysis of Multiple Optical Flow Values for Estimation of Unmanned Air Vehicles Height Above Ground”, SPIE Optics East, Robotics Technologies and Architectures, Intelligent Robots and Computer Vision XXII, vol. 5608, p. 298-305, Philadelphia, PA, USA, October 25-28, 2004.