APPROACH TO ANALYSE SEASONAL AND GEOGRAPHICAL VARIATIONS IN DAYLIGHT ILLUMINANTS

摘要

Based on 622 spectral measurements, a reconstruction approach for spectral power distributions of daylight was proposed in 1964. This procedure allows to derive the spectral power distribution of daylight illuminants from their chromaticity coordinates or correlated colour temperature. It suggests that inexpensive sensors can be used to measure daylight and a representation of colour characteristics of daylight can be done with just one single value, without large errors. The reconstruction approach was adopted by the CIE, nonetheless, emphasising that geographical and seasonal variations might exist. Up until today, these variations are investigated in single studies. This paper includes a review of relevant parameters that affect the reconstruction procedure and proposes a template for spectral measurements, to be used in a large worldwide measurement campaign, to modify or complement the existing CIE approach for reconstitution of daylight's spectral power distribution.