Defining the visual adaptation field for mesopic photometry: How does the high-luminance source affect peripheral...

CIE 191:2010 recommends the mesopic photometry system, in which the luminous efficiency function is determined from the adaptation luminance. However, it cannot be implemented because the adaptation field to determine the adaptation luminance is not defined. Surrounding luminance effect is a key factor to define the adaptation field. Vision experiments have been conducted to measure the surrounding luminance effect on peripheral adaptation state with a point source at varied intensities placed at different position. The results reveal that the effect can be described as veiling luminance and that the magnitude of the effect is larger than that of the foveal veiling luminance. A model for the peripheral veiling luminance proposed by Stiles and Crawford in 1937 shows the best prediction for the surrounding luminance effect.