Abstract

Like other aspects of color vision, interactions between the visual pathways of the long-wave-sensitive (LWS) and the middle-wave-sensitive (MWS) photoreceptors can no longer be regarded only as functions of wavelength. The results of color matching, detection, discrimination, and cancellation procedures may also vary with spatial and/or temporal properties of the stimulus. In some ways, these two stimulus dimensions have analogous effects on color perception. For example, responses to isoluminant, red/green, sine-wave stimuli are low pass in both spatial and temporal frequency domains, and responses to monochromatic or achromatic stimuli emphasize higher frequencies in both domains. But some chromatic interactions with space and time are quite different often due to physical constraints. Because they are not limited to one dimension, spatial patterns can have properties that temporal waveforms cannot involving orientation or symmetry. The spatial response of a chromatic mechanism can be symmetric about the stimulus but its temporal response cannot due to the causality constraint (time's arrow). Thus the simplest model for spatial phase relations—a linear filter with zero phase-shift—is forbidden in the temporal case.

© 1987 Optical Society of America