Outside-in Electromagnetic Tracking Method for Augmented and Virtual Reality 6-Degree of Freedom Head-Mounted Displays

Abstract

Tracking of position and orientation in 3D space termed as 6-Degree of Freedom, is critical for head-mounted displays to experience immersive content in augmented reality and virtual reality applications. Today’s outside-in tracking system commonly uses a light-based tracking method which is very accurate but has limitations of occlusion and line of sight dependency, causing loss of track and bad user experience. In this research work, we present a novel approach of an outside-in tracking system for augmented reality and virtual reality devices using electromagnetism which provides occlusion free and line of sight independent 6-degree of freedom tracking. The tracking method consists of a central coil wound in three orthogonal directions and a set of orthogonally wound receiver coil embedded in the head-mounted display. We propose a very novel closed-form and computationally in-expensive Beyond Line-of-Sight (PLoS) tracking approach to locate the position as well as the orientation angle of the head-mounted display (HMD) concerning the central magnetic coil. Our approach is independent of line-of-sight so the central coil unit can track the HMD in all directions with physical obstruction between the path of central unit and HMD. Our study demonstrates that this electromagnetism based approach can be used to track augmented reality and virtual reality HMD within the field range of the central magnetic coil. We have tested up to 100 cm (1 meter) range with an accuracy up to ± 1cm considering light-based outside-in tracking as ground truth.