Evaluating Luminance Uniformity Metrics Using Online Experiments

ABSTRACT

Luminance uniformity of luminaires is an important design aspect that can affect perceived discomfort glare, luminaire efficiency, and visual satisfaction. There is, however, a lack of studies that evaluated the performance of different luminance uniformity metrics. This article presents results of two studies where luminance patterns were presented via online questionnaires and subjective ratings of uniformity were collected. Study 1 examined the performance of a uniformity metric based on the human visual system (U_HVS) using a priori hypotheses, whereas Study 2 compared U_HVS to four other metrics: Max:Min, Avg:Min, entropy uniformity (EU), and coefficient of variation (CV) using correlations and non-linear models. Of the metrics evaluated, U_HVS performed best for predicting perceived luminance uniformity. In situations where a tradeoff between metric calculation simplicity and performance is acceptable, the use of CV is recommended.

KEYWORDS:

• Luminaire luminance uniformity
• luminance patterns
• uniformity metrics

Acknowledgments

We would like to acknowledge the help of Sarah Safranek for her help with pattern preparation for Study 2, and Robert Davis for reviewing an earlier draft of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15502724.2022.2133964

Additional information

Funding

This work was supported by the U.S. Department of Energy’s Lighting R&D Program, part of the Building Technologies Office within the Office of Energy Efficiency and Renewable Energy (EERE).