Perceived Change in Orientation from Optic Flow in the Central Visual Field

Abstract

An important consideration for some types of flight simulation is that sufficient information be provided for a veridical perception of a pilot's motion and/or change in orientation. Previous research (Andersen & Braunstein, 1985) has suggested that induced self-motion from stimulation of the central visual field may be related to internal depth within the display. The purpose of the present study was to examine the effects of internal depth within the display on perceived changes in orientation. Subjects monocularly viewed displays simulating observer motion within a volume of randomly positioned points through a window which limited the field of view to 15 degrees. The velocity of the displays varied according to a sum of four frequencies. Change in posture was used to measure changes in perceived spatial orientation. Three variables were examined: 1) the extent of internal depth within the display, 2) the presence or absence of visual information specifying change in orientation, and 3) the frequency of motion simulated by the display. A frequency analysis of postural sway indicated that increased sway occurred at frequencies of .375 Hz and lower when motion at these frequencies was present in the display. However, the extent of internal depth in the display had no consistent effect on the perception of changing orientation. The implications of this research for flight simulation will be discussed.