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Proceedings Paper

Spatiotemporal multiplexing of chromatic and achromatic information in human vision
Author(s): Eugenio Martinez-Uriegas
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Paper Abstract

Human vision is able to discriminate chromatic from achromatic changes under a wide variety of spatiotemporal conditions. Objectively, we distinguish physically between a light whose spectral energy distribution does not vary in space or time (except for a constant factor), and a light whose spectral distribution changes shape significantly, in either space or time or both. On the subjective level, we can visually discriminate spatiotemporal changes in hue from spatiotemporal changes in lightness. The general question of how to relate these subjective discriminations between chromatic and achromatic variations to the objective ones is still one of the basic problems at the core of visual science. Zone theories have generated opponent-color models that provide a useful framework to analyze these problems. According to those models, post-receptor processing is separated into independent channels, two color-opponent and one achromatic or luminance channel. Physiological and psychophysical data on spatiotemporal properties of chromatic and achromatic channels challenge the notion of chromatic-achromatic independence at an early stage, implying at least one intermediate process where the two types of information are intermixed. This intermediate stage can be modeled as an opponent multiplexing process. The multiplex model suggests decoding operations to separate chromatic and achromatic information at more central stages; and the implementation of those operations entails the generation of orientation selectivity. It is concluded that chromaticachromatic independence, a primal characteristic of human vision, must be implemented at stages located more centrally than previously thought. More generally, opponent multiplexing and the decoding algorithm are valid principles for any number of dimensions, which suggests that information processing other than vision could be studied from this perspective.

Paper Details

Date Published: 1 October 1990
PDF: 22 pages
Proc. SPIE 1249, Human Vision and Electronic Imaging: Models, Methods, and Applications, (1 October 1990); doi: 10.1117/12.19668
Show Author Affiliations
Eugenio Martinez-Uriegas, SRI International (United States)

Published in SPIE Proceedings Vol. 1249:
Human Vision and Electronic Imaging: Models, Methods, and Applications
Bernice E. Rogowitz; Jan P. Allebach, Editor(s)

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