POSTRACK: a low cost real-time motion tracking system for VR application

Abstract

One of the obstacles to the use of VR is the expensive, intrusive, cumbersome and brittle nature of the sensors required to detect user's intent. While optical tracking has been regarded as one solution to this problem, the problems of establishing marker correspondence and resolving their occlusions remain. One solution is to simply add hardware, making the tracking system too expensive for general usage, while another, to track human body parts, suffers from the inability to track point features. In this paper, we present a relatively inexpensive (e.g. runs on a high-end PC) but reasonably accurate tracking system, POSTRACK, that has many VR applications. It uses four cheap 8-bit grayscale cameras attached to infrared LED. The user wears several highly reflective markers. The markers are designed to be very easy to wear, and fashionable. The cameras are calibrated, and the initial marker assignments are found by a simple heuristic based on the normal human posture, while the fundamental matrices are used to find blob correspondence and compute the markers' 3D positions from their image centroids. These constantly change, so the position data are jittery. Results are presented.