OPTICS: Open-source Position Tracking Implementation with Consumer Smartphones

Motion capture systems can provide ground truth in millimeter accuracy for evaluating positioning algorithms but the high cost and specialized hardware requirements of current commercial solutions limit accessibility for many researchers. This paper presents OPTICS, an open-source, low-cost marker tracking system built using readily available hardware (smart-phones and consumer-grade measuring tools). The methodological contribution of this paper is related to the implementation of the camera calibration. Particularly, we present a novel approach for estimating reference points for extrinsic calibration using pairwise distances between ground reference markers without precisely manufactured reference objects. While the system shows some accuracy limitations compared to professional setups, OPTICS offers a viable alternative for preliminary evaluations and studies without access to a high-end motion capture system.