Conspicuity Of Aids To Navigation: Ii. Spatial Configurations For Flashing Lights.

Abstract

Lights used as aids to navigation are typically point sources that are easily confused with the background clutter of lights on shore. This study investigated the conspicuity, or how well lights of various spatial configurations stand out from a background of lights, and serves as a basis for the design of lighted aids to navigation. The measure of conspicuity was the response time for an observer to find a flashing target among backgrounds of steady lights on a CRT display. Twenty observers participated. There were nine targets tested, each at three temporal flash patterns and four background light densities. ANOVAS showed significant effects of target, flash pattern, and background. Simultaneously flashing the target elements of two horizontal bars of lights produced the greatest conspicuity, followed by two diagonal bars and a triad of lights. Search time increased with the density of background lights.