Effect of illuminance and spectrum on peripheral obstacle detection by pedestrians

Obstacle detection is an important visual task for pedestrians. An experiment was carried out to measure the ability to detect peripheral obstacles under variations of illuminance and S/P ratio and with older and younger test participants. The LED array used in this work enabled S/P ratio to be varied whilst chromaticity was held constant. The tests employed a full scale model with dynamic fixation to better simulate pedestrian experience than in past work. Detection performance increased with illuminance, reaching a plateau at 2.0 lux. A higher S/P ratio improved obstacle detection but only at the lowest illuminance used in this study (0.2 lux). Older participants showed poorer obstacle detection performance than younger participants but again only at the lowest illuminance.