IEVref:845-21-113ID:
Language:enStatus: Standard
Term: S/P ratio
Synonym1:
Synonym2:
Synonym3:
Symbol: RSP
Definition: ratio of the luminous output of a source evaluated according to the CIE scotopic spectral luminous efficiency, V′(λ), to the luminous output evaluated according to the CIE photopic spectral luminous efficiency, V(λ)

Note 1 to entry: The S/P ratio can be expressed by

R SP = K m 0 S(λ) V (λ)dλ K m 0 S(λ)V(λ)dλ MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadkfadaWgaaWcbaGaae4uaiaabcfaaeqaaOGaeyypa0ZaaSaaaeaa ceWGlbGbauaadaWgaaWcbaGaaeyBaaqabaGcdaWdXbqaaiaadofaca qGOaGaeq4UdWMaaeykaiaaykW7ceWGwbGbauaacaqGOaGaeq4UdWMa aeykaiaaykW7caqGKbGaeq4UdWgaleaacaqGWaaabaGaeyOhIukani abgUIiYdaakeaacaWGlbWaaSbaaSqaaiaab2gaaeqaaOWaa8qCaeaa caWGtbGaaeikaiabeU7aSjaabMcacaaMc8UaamOvaiaabIcacqaH7o aBcaqGPaGaaGPaVlaabsgacqaH7oaBaSqaaiaabcdaaeaacqGHEisP a0Gaey4kIipaaaaaaa@6302@

where Km ≈ 1 700 lm·W−1 is the maximum luminous efficacy for scotopic vision, Km ≈ 683 lm·W−1 is the maximum luminous efficacy for photopic vision, S(λ) is the relative spectral distribution of the source, and λ is the wavelength.

Note 2 to entry: The S/P ratio has unit one.


Publication date:2020-12
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