CIE 191:2010 recommends a mesopic photometry system that defines the luminous efficiency function for peripheral visual tasks, which vary depending on adaptation state of observers. For implementation of the system, an adaptation field to determine the adaptation state needs to be defined. To address this issue, vision experiments have been conducted to measure surrounding luminance effect on the adaptation state at a peripheral task point. The results reveal that the adaptation state depends mainly on the local luminance at the task point but there is also a small effect by surrounding luminance. The results suggest that the surrounding luminance effect is larger than the veiling luminance predicted with existing foveal models, nevertheless it is not significant for the mesopic luminance on uniform luminance distributions.
Citation: Lighting Research & Technology
Pub Type: Journals
adaptation field, luminance contrast detection threshold, mesopic photometry, visual task performance, veiling luminance