Influence of field-of-view (FOV) size and depth range on heading perception with or without visual path information

Abstract

We have previously shown that humans can perceive heading without visual path information (Li et al, 2006 Journal of Vision 6 874 - 881). Here we examine how varying two key parameters for estimating heading from optic flow, FOV size, and depth range of environmental points, influences human heading perception with or without visual path information. The display simulated an observer travelling on a circular path. Observers used a joystick to rotate their line of sight until deemed aligned with true heading. Four FOV sizes (110 deg694 deg, 48 deg641 deg, 16 deg614 deg, 8 deg67 deg) and depth ranges (6 - 50 m, 6 - 25 m, 6 - 12.5 m, 6 - 9 m) were tested. Heading bias increased with the reduction of FOV size or depth range when the display did not contain visual path information relative to when the display did contain such information (mean heading-bias ± SE: 4:88 ± 1:08 vs 2:28 ± 0:88 and 3:98 ± 0:38 vs 2:28 ± 0:58 for FOV size with N = 5 and depth range with N = 6, respectively). Human heading and path perception are independent. Path helps heading perception when the display does not contain enough optic flow information.