m-EDI Measurement Using Low-Cost Spectrometric Sensors Based on Photodiode Arrays with Narrowband Color Filters: An...

Area of Science:

• Photometry and Radiometry
• Human Health and Circadian Rhythms
• Sensor Technology

Background:

• Lighting significantly influences circadian rhythms and human health.
• Melanopic Equivalent Daylight Illuminance (m-EDI) quantifies blue light exposure per CIE S 026.
• Low-cost spectrometric sensors can estimate m-EDI but require calibration due to variability.

Purpose of the Study:

• To analyze the sensitivity of standard m-EDI calibration methods to sensor spectral response and calibration illuminant selection.
• To develop and validate a revised calibration approach for improved accuracy and robustness of m-EDI estimation.
• To reduce the root-mean-square error in m-EDI measurements from low-cost sensors.

Main Methods:

• Analysis of standard multiple linear regression calibration for spectrometric sensors.
• Investigation of sensor spectral response and calibration source selection impacts.
• Development of a revised calibration method involving selective channel discarding.

Main Results:

• Standard calibration is sensitive to sensor characteristics and illuminant choice.
• The proposed revised calibration method significantly improves accuracy.
• Root-mean-square error reduced from 17.6 to 1.36 lux for test LEDs.

Conclusions:

• A novel, selective channel discarding calibration method enhances m-EDI measurement accuracy.
• This improved calibration is vital for reliable assessment of lighting's impact on circadian health.
• The findings support the use of cost-effective sensors for critical lighting research.