In 1995 the CIE Technical Committee 3-13 developed the Unified Glare Rating (UGR) to predict discomfort glare for indoor lighting systems. For practical reasons, the UGR is based on the average source luminance. The introduction of LEDs in general lighting enabled many new luminaire designs, sometimes with unprecedented high luminance contrasts. The literature review presented in this report shows that UGR tends to underestimate the discomfort provoked by such luminaires with highly non-uniform source luminance. [more]
