Calibration of diverse tracking systems to enable local collaborative mixed reality applications

Mixed reality (MR) devices offer advantages for a wide range of applications, e.g. simulation, communication or training purposes. Local multi user applications allow users to engage with virtual worlds collaboratively, while being in the same physical room. A shared coordinate system is necessary for this local collaboration. However, current mixed reality platforms do not offer a standardized way to calibrate multiple devices. Not all systems offer the required hardware that is used by available algorithms, either because the hardware is not available or not accessible by developers. We propose an algorithm that calibrates two devices using only their tracking data. More devices can be calibrated through repetition. Two MR devices are held together and moved around the room. Our trajectory-based algorithm provides reliable and precise results when compared to SfM or marker based algorithms. The accurate, but easy to use rotational calibration gesture can be executed effortlessly in a small space. The proposed method enables local multi user collaboration for all six degrees of freedom (DOF) MR devices.