The visibility measuring system we developed can monitor an entire scene in a TV picture without focusing on particular targets. The correlation coefficient of visibility registered between this system and a reflector-type visibility sensor was O.92.Visibility fluctuates very little in falling snow and fog,but varies greatly,both spatially and temporally,in blowing snow and vehicle-generated snow clouds.The temporal and spatial characteristics of visibility attenuation in snowy conditions are presented.Using the TV camera,the visibility meter can monitor visual range in many locations in he picture localized visibility was compared at various points along highways. |