Characterizing and Calibrating the Novel PhaseSpace Camera System
Commercial vision based tracking systems are popular in robotics and aerial vehicle laboratories across the country for providing an inertial feedback measurement. Though Vicon is the most widely used, the PhaseSpace system offers a unique sensor with similar capabilities for a fraction of the cost. The PhaseSpace cameras utilize two linear imagers angled ninety degrees apart, each with their own cylindrical lens to focus light from mod- ulated beacons onto the imagers. The LED based beacons each blink a unique binary ID using full-power and half-power states allowing the 1-D information from each imager to be correlated and producing a site line much like a 2-D imager. This paper develops a detailed model of this unique, two imager camera, along with an empirical distortion model, and a calibration method is proposed and demonstrated. The PhaseSpace system was tested in its standard configuration with multiple cameras observing a dynamic rigid body, and the accuracy of the system is compared to Vicon. The system was also tested using a single camera in a simulated spacecraft rendezvous scenario to assess its capability as a 6-DOF localization sensor. All tests were run using both the "out of the box" calibration and the custom calibration developed. 2011 by the authors.