ABSTRACT
INTRODUCTION The Institut National de Metrologie du Conservatoire National des Arts et Métiers, laboratory belonging to the Groupement d'Interet Publique Bureau National de Metrologie (BNM-INM/CNAM) is the French national metrological laboratory in charge of realising the photometric and radiometric units. The primary reference for radiometric measurements is an electrically calibrated cryogenic radiometer. This equipment is able to achieve an accuracy better than 1.10-4 in the measurement of radiation emitted by lasers in the visible spectral range. All the radiometric and photometric measurements carried out in our laboratory are link to this primary standard. The quantities described in this paper deal only with photometry. The photometric measurements are used to quantify the visual effect of radiation on the human eye. But, as eye is a very complicated organ and not the same for everybody, it is necessary to define a standard observer which is mainly described by the luminous efficiency function V(2).
