Summary
This paper compares three major non-visual lighting metrics—Circadian Stimulus (CS2018, CS2021), melanopic Equivalent Daylight Illuminance (mEDI per CIE S 026), and melatonin suppression formulas—across a database of 884 light sources to clarify their interrelationships for practical use by lighting engineers. The key practical implication is that these metrics are highly correlated and can be converted between one another using linear transformations, simplifying the specification and evaluation of Human Centric Lighting systems.
Key Findings
- Analysis performed across a database of 884 light sources covering diverse light source technologies and daylight spectra.
- The updated CS2021 model (with CLA 2.0) resolves a discontinuity present in CS2018 at approximately 3710 K correlated color temperature, where the opponent channel signal (B-(L+M)) transitions between negative and positive values.
- All three non-visual metric groups (CS2021, mEDI/CIE S 026, and Giménez et al. melatonin suppression formula) show high mutual correlation coefficients, enabling linear transformation functions between them.
- One non-visual metric can be accurately converted to the other two via linear functions, reducing the practical burden of metric selection in integrative lighting design.
Categories
The Science of Light: Analyzes numerical relationships between non-visual metrics (CS2018, CS2021, mEDI) and brightness metrics across 884 light sources, directly relevant to lighting standards and melanopic EDI quantification.
Author(s)
KQ Tran, VQ Trinh, P Bodrogi
Publication Year
2023
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice