Temporal sensitivities related to color theory

Abstract

Sensitivities of color-normal observers to temporal variations in stimulus luminance and chromaticity were measured for sine-wave stimuli between 1.5 and 20 Hz. Clear differences were found in observers' sensitivities to isochromatic luminance variations and to isoluminous chromaticity variations for wavelength pairs selected to test temporal discriminability along the red-green and yellow-blue dimensions, respectively. Despite interobserver differences in individual red-green functions, a given observer's sensitivity could be described by a single curve shape specific to that observer. Overall sensitivity for yellow-blue was less than that for red-green for all observers. Differences in curve shape between red-green and yellow-blue functions are found for individual observers, but group averages reveal that the differences are not systematic. Red-green temporal sensitivity is largely unaffected by adapting backgrounds in red-green equilibrium but is attenuated at low frequencies by nonequilibrium backgrounds of the same luminance. Isochromatic luminance sensitivity is largely independent of our adapting backgrounds, but heterochromatic luminance modulation functions undergo expected changes in form.

Essay Concerning Color Constancy

“…Kelly & Burbeck believe that at low spatial frequencies, contrast sensitivity is closely related to mechanisms of lateral inhibition, which are spatially more diffuse than the excitatory pro cesses. The dependence of the effectiveness of suc.h mechanisms on illumina tion level is consistent with our own long-held conviction that visual adapta tion must involve postreceptoral changes as well as receptoral sensitivity adjustments (Hurvich & Jameson 1958, 1961, 1966Jameson 1985;Jameson & Hurvich 1956, 1959, 1961b, 1964, 1970, 1972Varner et al 1984).…”

Detecting and discriminating the direction of motion of luminance and colour gratings

“…This reversal in relative sensitivity to lurilinance. and colour gratings at the lower temporal frequency is analogous to the general finding that chromatic contrast sensitivity tends to be a low-pass function of temporal frequency, whereas luminance contrast sensitivity tends to be a band-pass function of temporal frequency (de Lange, 1958;Varner, Jameson & Hurvich, 1984).…”

Hybrid spatial‐temporal color synthesis and its applications

“…In particular, the resolution of the blue-yellow channel is severely limited and reveals that only relatively coarse spatial patterns can be resolved by the short-wavelength visual mechanism. Similar differences in the resolution of the opponent color channels have been found in the temporal domain, 3 and psychophysical determination of the temporal contrast sensitivity of the long (red), medium (green), and short-wavelength (blue) visual mechanisms, as shown in Fig. 3, reveals that the temporal resolution for short-wavelength visual input is very limited.…”