NOTE: This term was added in RP-16-17 Addendum 3.
In roadway lighting:
At a surface of a medium, in a given direction, under specified conditions of illumination: The quotient of the luminance of the surface element in the given direction by the illuminance on the medium, expressed by:
q = L/E ,
L is the luminance in cd/m2
E is the illuminance in lx
Unit: sr-1« Back to Definitions Index