Interaction- Hardware Support

Head and Hand Tracking - HiBall

The UNC and Utah sites collaborated on several joint design-and-manufacture efforts, including the design and rapid production of a head-tracker component (HiBall) (now used in the experimental UNC wide-area ceiling tracker)

Precise, unencumbered tracking of a user's head and hands over a room-sized working area has been an elusive goal in modern technology and the weak link in most virtual reality systems. Current commercial offerings based on magnetic technologies perform poorly around such ubiquitous, magnetically noisy computer components as CRTs, while optical-based products have a very small working volume and often need to maintain line-of-sight access between tracking cameras and illuminated beacon targets (LEDs). Lack of an effective tracker has crippled a host of augmented reality applications in which the user's views of the local surroundings are augmented by synthetic data (e.g., location of a tumor in the patient's breast or the removal path of a part from within a complicated piece of machinery).

For years UNC has been pursuing a variety of new approaches to head and hand tracking, principally with DARPA funding but also with Center support. Our latest system, an optical tracker with a golf-ball-sized tracking target that is either worn on the head or held in the hand, consists of a miniature cluster of six optical sensors looking out onto a specially outfitted room whose ceiling tiles have been embedded with infrared LEDs. The system is fully operational and has exceeded initial expectations: operating anywhere in a large (20 x 20 foot) room at a 1khz update rate, exhibiting resolution of under 1mm with excellent stability. The system itself has made possible a host of formerly stymied applications.

The system results from a satisfying collaboration among UNC, Utah, Brown, and Caltech. Its excellent performance encourages us to develop future trackers that will be able to operate outside the instrumented rooms, e.g., outdoors, whose target can be miniaturized not merely into a golfball sized enclosure but can be embedded, for instance, within normal (appearing) eyeglass frames. The availability of such radically improved trackers may well stimulate a wide variety of new applications, from on-site architecture planning to allowing emergency rescue personnel to see inside buildings.

The HiBall tracking technology has recently been licensed to 3rd Tech, Inc. in Chapel Hill, NC, from whom a commercial system is available and has been shipping since November 2000.