Mesopic spectral sensitivity functions based on visibility and recognition contrast thresholds.

Human vision works in a complex way in the mesopic luminance range which is not yet clearly understood, although several important visual tasks are performed at these luminance levels. In this study, spectral data for detection visibility and recognition contrast sensitivity were obtained in visual experiments. From our data it appears that chromatic channels also influence mesopic contrast sensitivity. An achromatic model of spectral sensitivity is fitted to our experimental data and the remaining chromatic components are discussed.