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Description / Abstract:
Summary
The CIE Supplementary System of Photometry, which evaluates
lights in terms of comparative brightness relationship at any
level, is described. The system introduces the concept of
equivalent luminance to describe brightness of a light or an object
at any level including mesopic levels. The system develops a
photometric model to calculate brightness-related equivalent
luminance by using three components of existing photometric and
colorimetric quantities (photopic luminance, L, scotopic luminance,
L′, and chromatic contribution to brightness, c, i.e.
brightness-to-luminance ratio (B/L)) with some weighting factors in
their combinations that depend on the adaptation level. The use of
the system and an example of calculation are also described.
Results of testing the system with experimental brightness matching
data are given in an appendix.