IEVref:845-31-020ID:
Language:enStatus: Standard
Term: Koschmieder's law
Synonym1:
Synonym2:
Synonym3:
Symbol:
Definition: 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.


Publication date:2020-12
Source
Replaces:
Internal notes:
CO remarks:
TC/SC remarks:
VT remarks:
Domain1:
Domain2:
Domain3:
Domain4:
Domain5: