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luminance coefficient

qv; q

quotient of the luminance at a surface element of a medium in a given direction and the illuminance on the medium

where Lv is luminance and Ev is illuminance

Note 1 to entry: The bi-directional reflectance distribution function (BRDF) is similar to the luminance coefficient except that it is defined for directional incident radiation.

Note 2 to entry: The luminance coefficient is expressed in steradian to the power minus one (sr−1).

Note 3 to entry: This entry was numbered 845-04-71 in IEC 60050-845:1987.

Note 4 to entry: This entry was numbered 17-712 in CIE S 017:2011.

Publication date: 2020-12
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