VISIBILITY EVALUATION FOR FACE OF PERSON STANDING UNDER LED STREET LIGHTING ENVIRONMENT

摘要

In this research, we performed the field experiments during night to determine the effect of LED street lighting on pedestrian visibility. A total of five different LED sources were used: three different luminous flux levels and two different types of mounted diffusion filters. We also added two other types of lights for comparison: fluorescent light and HID mercury vapour lamp. We used human faces as the objects of visibility evaluations. The first finding of our research was that a 1,000 lm LED light and a 2,000 lm LED light with an 80° diffusion plate provided low illumination of the object surface, and had lower evaluation values than did the other lights. Our second finding was that the evaluation values for 2,000 lm LED light; 3,000 lm LED light; and 2,000 lm LED light with 20° diffusion plate were higher than the first two LED lamps and about the same as that of fluorescent lamp. Our third finding was that HID mercury vapour lamps had the highest evaluation among any lighting type employed in the experiment.