Basic Study on visual effetiveness airport coloured lights

摘要

References(5) Airport lights are installed in or around the runway in order to convey appropriate visual information to an approaching pilot. Such coloured lights as white, red, green or blue are used as appropriate to their functions as visual aids. The visual effectiveness of airport lights is a function of their colour, the background luminance (daytime, twilight or night) and the visibility. In the past, effectiveness has been investigated only at the visual threshold under clear visibility. For more precise and quicker pilot reaction during the actual approach phase, however, studies of the visual effect with far higher illuminance than visual threshold are required, furthermore the identification of lights under low visibility conditions must be taken into consideration. A fog chamber is used for this comparative analysis among 4 coloured light sources (white, red, yellow and green) with a 3-minute visual angle. As for visual effect levels, the 4 levels of illuminance at the observer’s eye using point sources are chosen, namely, illuminance threshold, chromatic threshold, optimum illuminance, and lower limit of glare. Each level is measured under various conditions background luminance and visibility. The following results were obtained from this study.(1) Irrespective of fog condition, the illuminance required for each visual level increases as the background luminance increases. Larger increments are required after the background luminance exceeds 1 cd/m2.(2) Without fog in the chamber, the chromatic threshold of red is relatively low and that of green is comparativily high, while those of white and yellow fall between red and green. The ratios of optimum value to chromatic threshold for the 4 colours are 80 to 500 in dark background and those decrease as background luminance increases.(3) With fog in the chamber, there are no remarkable differences relatively low chromatic thresholds. The ratios of optimum to chromatic threshold of the 4 colours are 15 to 40 in the dark.