[OPTICAL REVIEW Vol. 8, No. 3 (2001) 198-202]
Brightness Perception of Light Source Colors in Dense Fog
Mamoru TAKAMATSU* and Yoshio NAKASHIMA
Faculty of Engineering, Toyama University, 3190, Gofuku, Toyama, 930-8555 Japan
(Received January 11, 2001; Accepted March 23, 2001)
The characteristics of our color vision are affected by various visual environments. In this experiment, we examined how colored lights look in dense fog. We used 12 kinds of colored light as a test stimulus. At first, in the absence of fog, subjects matched brightness of all the test stimuli with a reference white light adjusted to 0.1 cd/m2 or 0.5 cd/m2 in luminance, respectively. They then evaluated the apparent brightness of the test stimuli in dense fog with magnitude estimation of 10 grades. In the presence of fog, test stimuli containing a yellow component were given the highest point value of brightness, while test stimuli containing a blue component were given the lowest point value of brightness in fog. We are confident that in a visual environment involving fog, these results will be extremely helpful and practical.
Key words : visual characteristics, dense fog, characteristics of color vision, traffic visual environments, illuminance level