THE ROLE OF SYSTEM LATENCY IN MULTI-SENSORY VIRTUAL DISPLAYS FOR SPACE APPLICATIONS

摘要

In any virtual environment (VE), system parameters such as the update rate and the total system latency (TSL) may have a significant impact on the smoothness and responsiveness of the dynamic simulation if they exceed perceptual tolerances. The TSL refers to the time elapsed from the transduction of an event or action, such as movement of the head or hand, until the consequences of that action cause the equivalent change in a virtual source/object. The source and magnitude of these latencies may depend upon the context in which the virtual display is used. In space applications, TSLs may include the basic computational overhead in rendering the VE in typical ground-based tasks, as well as the more significant delays (0.4―6 s; Sheridan, 1992) produced by satellite and other communications delays during space-based activities. The presence of latencies creates the potential for a decoupling between the vestibular/kinesthetic sensation of motion and the consequences of motion in the sensory world. Such a decoupling can cause various undesirable perceptual effects, including positional instability of objects or an effective compression of the VE's response to head or hand motion. Recent research has investigated the impact of increasing latency on such measures as localization accuracy for virtual sounds and the ability of viewers to discriminate between different latencies in a visual virtual environment. It appears that subjects are less sensitive to latency in the auditory than in the visual domain, and highly sensitive in the haptic domain.