Determination and Measurement of Melanopic Equivalent Daylight (D65) Illuminance (mEDI) in the Context of Smart and Integrative Lighting

Abstract

In the context of intelligent and integrative lighting, in addition to the need for color quality and brightness, the non-visual effect is essential. This refers to the retinal ganglion cells ((Formula presented.)) and their function, which were first proposed in 1927. The melanopsin action spectrum has been published in CIE S 026/E: 2018 with the corresponding melanopic equivalent daylight (D65) illuminance ((Formula presented.)), melanopic daylight (D65) efficacy ratio ((Formula presented.)), and four other parameters. Due to the importance of (Formula presented.) and (Formula presented.), this work synthesizes a simple computational model of (Formula presented.) as the main research objective, based on a database of 4214 practical spectral power distributions (SPDs) of daylight, conventional, LED, and mixed light sources. In addition to the high correlation coefficient (Formula presented.) of 0.96795 and the 97% confidence offset of 0.0067802, the feasibility of the (Formula presented.) model in intelligent and integrated lighting applications has been extensively tested and validated. The uncertainty between the (Formula presented.) calculated directly from the spectra and that obtained by processing the RGB sensor and applying the (Formula presented.) model reached ± 3.3% after matrix transformation and illuminance processing combined with the successful (Formula presented.) calculation model. This result opens the potential for low-cost RGB sensors for applications in intelligent and integrative lighting systems to optimize and compensate for the non-visual effective parameter (Formula presented.) using daylight and artificial light in indoor spaces. The goal of the research on (Formula presented.) sensors and the corresponding processing method are also presented and their feasibility is methodically demonstrated. A comprehensive investigation with a huge amount of color sensor sensitivities is necessary in a future work of other research.