Cortical dynamics of three-dimensional form, color, and brightness perception: I. Monocular theory

Abstract

A real-time visual processing theory is developed to explain how three-dimensional form, color, and brightness percepts are coherently synthesized. The theory describes how several fundamental uncertainty principles which limit the computation of visual information at individual processing stages are resolved through parallel and hierarchical interactions among several processing stages. The theory hereby provides a unified analysis and many predictions of data about stereopsis, binocular rivalry, hyperacuity, McCollough effect, textural grouping, border distinctness, surface perception, monocular and binocular brightness percepts, filling-in, metacontrast, transparency, figural aftereffects, lateral inhibition within spatial frequency channels, proximityluminance covariance, tissue contrast, motion segmentation, and illusory figures, as well as about reciprocal interactions among the hypercolumns, blobs, and stripes of cortical areas VI, V2, and V4. Monocular and binocular interactions between a Boundary Contour (BC) System and a Feature Contour (FC) System are developed. The BC System, defined by a hierarchy of oriented in-.teractions, synthesizes an emergent and coherent binocular boundary segmentation from combinations of unoriented and oriented scenic elements. These BC System interactions instantiate a new theory of stereopsis and of how mechanisms of stereopsis are related to mechanisms of boundary segmentation. Interactions between the BC System and the FC System explain why boundary completion and segmentation processes become binocular at an earlier processing stage than do color and brightness perception processes. The new stereopsis theory includes a new model of how chromatically broadband cortical complex cells can be adaptively tuned to multiplex information about position, orientation, spatial frequency, positional disparity, and orientational disparity. These binocular cells input to spatially short-range competitive interactions (within orientations and between positions, followed by between orientations and within positions) that initiate suppression of binocular double images as they complete boundaries at scenic line ends and comers. The competitive interactions interact via both feedforward and feedback pathways with spatially long-range-oriented cooperative gating interactions that generate a coherent, multiple-scale, three-dimensional boundary segmentation as they complete the suppression of double-image boundaries. The completed BC System boundary segmentation generates output signals, called filling-in generators (FIGs) and filling-in barriers (FIBs), along parallel pathways to two successive FC System stages: the monocular syncytium and the binocular syncytium. FIB signals at the monocular syncytium suppress monocular color and brightness signals that are binocularly inconsistent and select binocularly consistent, monocular FC signals as outputs to the binocular syncytium. Binocular matching of these FC signals further suppresses binocularly inconsistent color and brightness signals. B...

Color from Motion: Separate Contributions of Chromaticity and Luminance

“…Thus, in these conditions observers see the spread of subjective color without seeing a distinct subjective contour, suggesting that color spread and the formation of a subjective contour are governed by separate mechanisms. This is parallel to findings which show that color spread and contour formation in the static neon color display are governed by separate mechanisms (Grossberg andMingolla 1985a, 1985b;Grossberg 1987;Watanabe and Sato 1989). For conditions with test and surround dots of the same chromaticity (both red or both green) and of different luminances, color spread was perceived if the test dots were more luminous than the surround dots but not when the test dots were less luminous than the surround dots (figure 4, bottom two panels).…”

“…Redies and Spillmann (1981) showed that the spread of neon color occurs in the static display even at equiluminance, as was confirmed experimentally by Ejima et al (1984). Grossberg andMingolla 1985a, 1985b;Grossberg 1987) proposed a model in which two separate mechanisms are postulated, one to produce color spreading and the other to produce the subjective contour. In line with this model, the experiments of Watanabe and Sato (1989) showed that the neon color effect is seen without a subjective contour when the inner and outer segments are near equiluminance, suggesting that the perception of color spreading and the formation of a subjective contour are governed by two different mechanisms.…”

Cortical dynamics of three-dimensional figure–ground perception of two-dimensional pictures.

“…A horizontal bipole cell is also inhibited by activation of vertical hypercomplex cells ( Figure 13A). This spatial impenetrability operation (Grossberg, 1987a;Grossberg & Mingolla, 1987) prevents collinear grouping from occurring across regions wherein noncollinear orientations are present.…”

“…In other words, end-cuts were not introduced in the model to explain boundary detachment. They were introduced to explain how the visual system compensates for measurement uncertainties that are caused by using oriented receptive fields, a much more basic requirement (Grossberg, 1987a;Grossberg & Mingolla, 1985b).…”

Effects of luminance contrast on color spreading and illusory contour in the neon color spreading effect

“…Grossberg and Mingolla (Grossberg, 1987; Gossberg & Mingolla, 1985a, 1985b have, in fact, constructed a model in which the mechanism for the color spreading is different from that for the illusory contour formation.…”