The effect of stimulus duration on the luminous efficiency functions for brightness

Abstract

AbstractSpectral luminous efficiency functions were obtained by direct heterochromatic brightness matching for four different stimulus durations: namely, 10‐ms, 200‐ms, 1‐s, and continuous presentation. The functions clearly changed in their shape, depending on the stimulus duration for two of three subjects. They showed usual double peaks at about 540 and 600 nm, which were greatly enhanced when the duration was 1 s. The enhancement decreased both with longer and shorter duration. Linear combinations of cone outputs model was applied to our results. The logR‐logG type mechanism in the long‐wavelength region and the logG‐logR‐logB type mechanism in the middle‐wavelength region were found for brightness perception. For the short‐wavelength region, by lifting up the short‐wavelength portion of the logR‐logG mechanism, luminous efficiency functions could be expressed. In the long‐ and middle‐wavelength region, the effects of the stimulus duration were explained by changing the negative input (originating from R or G cones) to the positive input as the stimulus duration increased from 10 ms to 1 s. The amount of the short‐wavelength sensitive cones' contribution in the middle‐wavelength region were small and there were no systematic changes for the stimulus durations. For the short‐wavelength region, the amount of the shift of the logR‐logG type mechanism was largest at the 1‐s duration.