cie

17-22-085

visibility level

FVL

quotient of the real difference in luminance between the target and its background, ΔL, and the luminance difference needed between a target of a certain angular size and its background for the target to be just visible, ΔLth, that is at the threshold
FVL = ΔL / ΔLth

Note 1 to entry: The visibility level indicates how much the contrast of the target is above threshold contrast.

Note 2 to entry: The visibility level has unit one.

Note 3 to entry: This entry was numbered 17-1401 in CIE S 017:2011.

Publication date: 2020-12
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