Visual information transmission to navigators for the navigation safety

Abstract

For the navigators during coastal navigation at night, signal lights such as the navigational aids and the navigation lights of other ships should have a good visual transmission from the view point of navigation safety. In this paper the relation between the recognition of the signal and background lights is described. The measured results of background lights using a wide-angle luminance meter of 20° visual field show that the city lights of medium and small sized cities at night have generally the average luminance of about 10^-3 to 10^-1 cd/m² when viewed through clear atmosphere. In order to study various factors affecting the signal recognition an indoor experiment was conducted using a model set in a fog chamber, however, without generating fog in this study. Furthermore, the effect of peripheral vision is discussed.