Quantifying biologically essential aspects of environmental light

Research output: Contribution to journalArticlepeer-review


Quantifying and comparing light environments are crucial for interior lighting, architecture and visual ergonomics. Yet, current methods only catch a small subset of the parameters that constitute a light environment, and rarely account for the light that reaches the eye. Here, we describe a new method, the environmental light field (ELF) method, which quantifies all essential features that characterize a light environment, including important aspects that have previously been overlooked. The ELF method uses a calibrated digital image sensor with wide-angle optics to record the radiances that would reach the eyes of people in the environment. As a function of elevation angle, it quantifies the absolute photon flux, its spectral composition in red-green-blue resolution as well as its variation (contrast-span). Together these values provide a complete description of the factors that characterize a light environment. The ELF method thus offers a powerful and convenient tool for the assessment and comparison of light environments. We also present a graphic standard for easy comparison of light environments, and show that different natural and artificial environments have characteristic distributions of light.

Original languageEnglish
Article number20210184
Number of pages12
JournalJournal of the Royal Society, Interface
Issue number177
Publication statusPublished - 2021 Apr 1

Subject classification (UKÄ)

  • Biophysics

Free keywords

  • camera
  • environmental light
  • environmental light field
  • human vision
  • measurement method
  • radiometry


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