A generic, visual system-based model for discomfort from glare

Conventional measures of discomfort from glare are based on glare source properties like luminous intensity or luminance and typically are valid only to specific situations and to specific types of light sources. For instance, the unified glare rating (UGR) is intended for indoor lighting conditions with medium-sized glare sources, whereas another class of glare measures is specifically devoted to car headlamps. Recently, CIE TC 3-57 started with the aim to develop a more generic glare sensation model based on the human visual system. We present an example of such a model, including a detailed description of aspects like pupil constriction, retinal image formation, photoreceptor response and adaptation, receptive field-type filtering in the retina and neural spatial summation. The linear correlation of the model to UGR in an indoor setting and to subjective glare responses in an outdoor-like setting indicate that the human-visual-system-based model may indeed be considered generic.