Fiducial Marker and Camera-Based Passive High-Accuracy 6-DoF Tracking for Mobile Objects

Accurate 6-DoF tracking technology is indispensable in robotics research, particularly for assessing the accuracy of 3D localization. We have developed an innovative 6-DoF tracking system for mobile objects that is cost-effective, passive, portable, scalable, and accurate. This proposed system employs high-accuracy markers, which have been enhanced from commonly used planar fiducial markers. All the operator needs to do is place these markers in the environment and on the measurement targets, and capture them with cameras. Subsequent processing, including marker measurements, establishing the world coordinate system, determining camera pose, outlier removal, calculating relative marker poses, handling occlusions, and generating 6-DoF tracking results, is automatically executed by the analysis software we have developed. We conducted experiments to measure the 6-DoF travel path of an electric wheelchair in a
$\mathbf{6}\times \mathbf{9}\ \mathbf{m}$
indoor space, demonstrating that highly accurate measurements with a position error of less than 10 mm and an orientation error of less than 0.5° were achievable.