The terms and definitions pursuant to the VIM and VIML1 as well as the terms and definitions specified in the following shall apply for the purposes of this General Measure:
1.1 lux metre device for measuring illuminance composed of an optical radiation detector and an electronic unit which converts the detector’s signal into a value which characterises the radiation incident on the detector.
NOTE: A lux metre is a special type of integral radiometer in which the detector part has a relative spectral responsivity corresponding to effective weighting function V(λ).
1.2 photoelectric transducer converts radiation in the visible range of the spectrum from 380 nm to 830 nm into an electrical signal using external or internal photoelectric effect.
1.3 CIE of standardised source A radiation of absolutely black body at temperature 2 856 K.
1.4 photopic vision daylight vision conveyed via the retinal cones with which it is possible to discern colours; develops when the eye adapts to radiance greater than 3 cd × m-2 NOTE: The spectral responsivity of radiation transducers in the case of photopic vision is defined by the function V (λ). The function V (λ) is a conventional function and is depicted in tabular form.
1.5 relative spectral sensitivity / relative spectral responsivitysrel (λ)
proportion of radiant flux at wavelength λm to the value of the radiant flux at wavelength λ which actuates perception in the human eye under defined conditions.
NOTE λ m = 555 nm is the wavelength at which the spectral responsivity of the average human eye is at its maximum in photopic vision.
1.6 integral characteristicf1'
describes the suitability of a detector’s spectral adaptation to the required spectral weighting function V (λ).
