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Area Lighting / Visual signalling

IEV ref 845-31-020

en
Koschmieder's law
law relating the apparent contrast, Cd, of an object against a sky background, at a given distance of observation, d, to the inherent contrast, C0, and to the atmospheric transmissivity, T, which is assumed to be uniform

C d = C 0 T d/ d 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4qamaaBa aaleaacaWGKbaabeaakiabg2da9iaadoeadaWgaaWcbaGaaGimaaqa baGccaWGubWaaWbaaSqabeaacaWGKbGaai4laiaadsgadaWgaaadba GaaGimaaqabaaaaaaa@3EEE@

where d0 is the length specified for the definition of T

Note 1 to entry: The formula is sometimes written

C d = C 0 T δ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadoeadaWgaaWcbaGaamizaaqabaGccqGH9aqpcaWGdbWaaSbaaSqa aiaaicdaaeqaaOGaamivamaaCaaaleqabaGaeqiTdqgaaaaa@3F01@

where the exponent, δ, in Tδ is the numerical value of d measured with d0 as "unit".

Note 2 to entry: Taking into account the relationship between atmospheric transmissivity, T, and meteorological optical range, v, given in Note 2 to entry of "meteorological optical range", Koschmieder's law can be also written as

C d = C 0 ( 0,05 d/v ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbb a9frFj0xb9Lqpepeea0xd9q8as0=LqLs=Jirpepeea0=as0Fb9pgea 0lrP0xe9Fve9Fve9qapdbaqaaiGadiWacmaacmqaaqaacaqbaaGcba Gaam4qamaaBaaaleaacaWGKbaabeaakiabg2da9iaadoeadaWgaaWc baGaaGimaaqabaGccaGGOaqcaaKaaGimaiaacYcacaaIWaGaaGynaO WaaWbaaSqabeaacaWGKbGaai4laiaadAhaaaGccaGGPaaaaa@47EE@

Note 3 to entry: The contrast is taken to be the quotient of the difference between the luminance of the object and the luminance of the background, and the luminance of the background.

Note 4 to entry: This entry was numbered 845-11-22 in IEC 60050-845:1987.


fr
loi de Koschmieder, f
loi associant le contraste apparent Cd, d'un objet sur un fond de ciel à une distance d'observation donnée, d, au contraste propre C0, de cet objet et à la transmissivité atmosphérique T réputée uniforme

C d = C 0 T d/ d 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4qamaaBa aaleaacaWGKbaabeaakiabg2da9iaadoeadaWgaaWcbaGaaGimaaqa baGccaWGubWaaWbaaSqabeaacaWGKbGaai4laiaadsgadaWgaaadba GaaGimaaqabaaaaaaa@3EEE@

d0 est la longueur spécifiée pour la définition de T

Note 1 à l'article: La formule est parfois écrite sous la forme

C d = C 0 T δ MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadoeadaWgaaWcbaGaamizaaqabaGccqGH9aqpcaWGdbWaaSbaaSqa aiaaicdaaeqaaOGaamivamaaCaaaleqabaGaeqiTdqgaaaaa@3F01@

où l'exposant, δ, dans Tδ est la valeur numérique de d mesurée avec d0 comme "unité".

Note 2 à l'article: Compte tenu de la relation entre la transmissivité atmosphérique T, et la portée optique météorologique, v, donnée à la Note 2 à l'article de la définition "portée optique météorologique", la loi de Koschmieder peut aussi s'écrire sous la forme

C d = C 0 ( 0,05 d/v ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbb a9frFj0xb9Lqpepeea0xd9q8as0=LqLs=Jirpepeea0=as0Fb9pgea 0lrP0xe9Fve9Fve9qapdbaqaaiGadiWacmaacmqaaqaacaqbaaGcba Gaam4qamaaBaaaleaacaWGKbaabeaakiabg2da9iaadoeadaWgaaWc baGaaGimaaqabaGccaGGOaqcaaKaaGimaiaacYcacaaIWaGaaGynaO WaaWbaaSqabeaacaWGKbGaai4laiaadAhaaaGccaGGPaaaaa@47EE@

Note 3 à l'article: Le contraste est considéré comme étant le quotient de la différence entre la luminance de l'objet et la luminance du fond par la luminance du fond.

Note 4 à l'article: Cet article était numéroté 845-11-22 dans l'IEC 60050-845:1987.


ar
قانون كوشميدر

cs
Koschmiederův zákon

de
Gesetz von Koschmieder, n

it
legge di Koschmieder

ko
코쉬 미더 법칙

ja
コシュミーダの法則

nl
nl wet van Koschmieder

nl
be wet van Koschmieder, f

pl
prawo Koschmiedera, n

pt
lei de Koschmieder

zh
科施米德定律

Publication date: 2020-12
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