Head-mounted displays and the measurement of performance in a virtual world

The problems associated with assessing visual performance during translation and rotation in a virtual world are presented. Two studies are summarized that highlight the difficulties in defining and measuring the optical and visual variables that pilots use during the control of a craft in simulated flight. The analysis suggests that gaze line-of-sight (LOS), based on craft orientation, should be used to describe the visual information available to an observer. Head-mounted displays that utilize a headtracker provide a technology that can be used for determining an observer's LOS and generating a virtual world display. Such head-mounted displays put observers in a graphical world that exists no matter where they look.