Texture Density Effects on Accuracy of Control of Egospeed are Nonlinear

Abstract

Knowledge of how the visual system determines the speed of self-motion is necessary for the design of virtual displays that will enhance accurate perception and control of airspeed, lower the incidence of loss of situational awareness and increase pilot performance. Changes in texture density have been shown to bias the perceived speed of moving 2D patterns (Watamaniuk, Grzywacz, & Yuille, 1993) and 3D self-motion or egospeed (Dyre, 1997; Ballard, Roach, and Dyre, 1998), suggesting that visual motion channels that code speed are also sensitive to changes in texture density. This study examined the relationship between display density and performance on a speed control task over a wide range of densities. Observers attempted to maintain constant speed while countering a simulated fore-aft wind disturbance. Overall, participants tended to increase speed (positive errors) over the trial duration for every condition. However, moderate densities produced less error than higher or lower densities. Precision of egospeed control was not affected by variations in density. These results show that texture density is an important parameter to consider in designing virtual displays and that moderate texture density levels may be the most effective for supporting control of speed.