Exploring spatiotemporal dynamics in light-dosimetry

Light-dosimetry aims to measure personal light exposure in real-life settings, allowing to investigate the role of light in visual, physiological, and behavioural processes. One aspect not yet considered in light-dosimetry is the spatial distribution of light in the field of view. Therefore, we developed and tested a novel measurement setup for spatially resolved light-dosimetry. The setup consisted of an industry-standard wide-angle video-radiometer (LMK) worn at the chest and two novel sensor prototypes: a miniature video-radiometer (alphaOmega-meter) and a spectrally resolved dosimeter (Spectrace), both worn at the chest and forehead. The LMK recorded melanopic radiance images at a sampling frequency of 0.5 Hz, achieved with a custom developed algorithm. The alphaOmega-meter recorded α-opic radiance images at 0.1 Hz and Spectrace recorded 14-channel spectral irradiance at 0.03 Hz. A series of test measurements were then conducted in various urban environments, to assess the potential of the measurement setup. Suitable evaluation methods for spatially resolved light-dosimetry data are presented, which may offer novel insights into the effects of light on visual and non-visual responses by enabling a closer approximation of retinal illumination compared to the spatially integrated measurements that are commonly used. Together, this study demonstrates the feasibility of incorporating spatial characteristics in light-dosimetry.