Examining perceptual luminance uniformity of simulated luminaire patterns

Abstract

Luminaire luminance uniformity is an important aspect that can affect perceived lighting quality, discomfort glare, and efficacy. While several metrics have been proposed to characterize luminance uniformity, previous studies have shown that current metrics such as Max:Min or Avg:Min luminance ratios can be insensitive to important differences in luminance gradient that may affect perceived uniformity. In an attempt to resolve this issue, previous studies incorporated a contrast sensitivity function for the human eye based on spatial frequency, such as in the recently proposed UHVS metric; however, this metric has not been comprehensively studied in relation to perceived uniformity ratings. The study presented in this paper aimed to examine the relationship between UHVS and perceived uniformity ratings. Specifically, simulated luminance patterns were presented, and participants were asked to assess uniformity using a twoalternative forced-choice procedure. The results of 94 participants’ evaluations showed a significant correlation between UHVS and perceived uniformity. However, comparisons between patterns that had similar UHVS sometimes resulted in statistically different ratings and comparisons between patterns that had larger differences in UHVS sometimes did not result in a statistically significant difference in ratings. These results suggest that UHVS might be used for general guidance but may warrant further studies to better understand its sensitivity and improve its alignment with perceived uniformity ratings.