Photometric measurements of lighting quality: An overview

This paper aims to provide an overview of various aspects used to measure the overall lighting quality, instead of solely focusing on a single aspect. Lighting quality is a concept that allows excellent vision while providing high comfort. However, it cannot be measured directly; although, it can be indicated by measuring different aspects of lighting quality individually. By reviewing thirty eligible studies, based on forward and backward citation, eleven lighting quality aspects were determined that influence the overall lighting quality. Preferably, control algorithms for high quality lighting implement all these aspects; however, current control algorithms generally have a limited focus on energy or one or two specific aspects. Consequently, these control algorithms do not necessarily provide high quality lighting. This paper reviews measurement methodologies for the variable aspects of lighting quality, namely quantity, distribution, glare, spectral power distribution, daylight, directionality, and dynamics. We distinguish ad hoc and continuous measurements for each aspect. Ad hoc measurements are single measurements that provide a high accuracy "snapshot"; continuous measurements have a lower accuracy but provide a good overview over time that is relevant as input for lighting control algorithms optimizing the lighting quality. This overview shows that luminance distribution measurement devices are highly suitable for measuring lighting quality for both ad hoc and continuous measurements. Except the spectral power distribution, all variable aspects of lighting quality can be measured using such a device although the aspects directionality and dynamics still require more suitable luminance based indicators. Hence, it can be concluded that a luminance distribution measurement device is very suitable device to provide relevant input for lighting quality control algorithms.