Abstract
Purpose. We measured observers' ability to adjust their heading direction at different eye-heights and with simulated pursuit fixation on one target. In a previous experiment using the same display, we established that passively driven observers performed better with increased elevation. However in driving most attention might be allocated to relative object motion, while other information related to global flow is used less effectively. Methods: Stimulus trials simulated locomotion across a textured plane with trees, and with fixation on a central tree. The task was to adjust heading by moving a mouse in direction of the fixation tree. Each trial consisted of a 12-s motion sequence showing a group of trees observed from 4 different eye heights (1.25, 1.6, 3.2 and 16 m). Thresholds were computed from adjustments of heading responses. Results. At lower eye-heights (1.25 & 1.6 m) heading errors were smaller than 4\[DownExclamation] and closer to accustomed values, but at higher eye heights thresholds increased to 8\[DownExclamation] of angle. Conclusion. Drivers do not appear to benefit from the decrease in texture compression with increase in elevation because they have to keep their gaze oriented towards the trees to be reached. Future research will investigate this assumption with eye records to establish if comparatively less time is spent to explore layout surface in this case.
Supported by Swiss FNSRS Grant 1114-57239.99.