Equivalent veiling luminance caused by small glare light source near the visual line

An experiment was conducted on the degradation of visibility when affected by glare light sources near the visual line, to examine the effects of glare light source size and eccentricity, and background luminance on the equivalent veiling luminance. In this experiment, a circular glare light source of diameter 3 to 27 minutes was presented near the visual line of an observer. Landolt rings were employed as test objects on a screen panel. When the size of the glare light source was relatively small, the rate of degradation in visibility depended on not only the luminous intensity of the light but also its siz.