Neon Flank and Illusory Contour: Interaction between the Two Processes Leads to Color Filling-in

Perception ◽  
1992 ◽  
Vol 21 (3) ◽  
pp. 313-324 ◽  
Author(s):  
Hiroshige Takeichi ◽  
Shinsuke Shimojo ◽  
Takeo Watanabe
Keyword(s):  
Visual Processing ◽  
Illusory Contour ◽  
Feature Detection ◽  
Illusory Contours ◽  
Local Color ◽  
Color Spreading ◽  
Surface Separation ◽  
Dichoptic Viewing ◽  
Contour Interaction ◽  
Neon Color Spreading

Two aspects of neon color spreading, local color spreading (neon flank) and illusory contour, were investigated by dichoptic viewing. Neon flank was not observed under appropriate dichoptic stimulation, suggesting that input to the process for local color spreading is based on monocular configuration. However, illusory contours were formed according to the interocularly combined configuration rather than according to each monocular configuration, suggesting that input to the process responsible for illusory contours should be ocularly-nonselective and binocular, rather than monocular. The possibilities of artifacts such as those arising from interocular rivalry were appropriately eliminated, and thus, it is tentatively concluded that the process underlying local color spreading is monocularly driven, whereas the process underlying illusory contours is binocularly driven. Furthermore, a new demonstration is presented that indicates that interocularly-induced illusory contours ‘capture’ and extend the monocularly-induced local color spreading, resulting in global color spreading (neon color spreading). These results support our hypotheses that neon color spreading involves two separable processes in the early visual processing, the feature detection process (for local color spreading) and the illusory contour process, and that these two processes interact with each other at later stages of cortical processing. The relation of local color spreading and illusory contours to surface separation is also discussed.

How a Brain Sees: Neural Mechanisms

2021 ◽  
pp. 122-183
Author(s):  
Stephen Grossberg
Keyword(s):  
Illusory Contour ◽  
Local Contrast ◽  
Simple Complex ◽  
3D Vision ◽  
Color Spreading ◽  
Surface Filling ◽  
Contour Strength ◽  
Neon Color Spreading ◽  
Glass Patterns ◽  
Boundary Completion

Multiple paradoxical visual percepts are explained using boundary completion and surface filling-in properties, including discounting the illuminant; brightness constancy, contrast, and assimilation; the Craik-O’Brien-Cornsweet Effect; and Glass patterns. Boundaries act as both generators and barriers to filling-in using specific cooperative and competitive interactions. Oriented local contrast detectors, like cortical simple cells, create uncertainties that are resolved using networks of simple, complex, and hypercomplex cells, leading to unexpected insights such as why Roman typeface letter fonts use serifs. Further uncertainties are resolved by interactions with bipole grouping cells. These simple-complex-hypercomplex-bipole networks form a double filter and grouping network that provides unified explanations of texture segregation, hyperacuity, and illusory contour strength. Discounting the illuminant suppresses illumination contaminants so that feature contours can hierarchically induce surface filling-in. These three hierarchical resolutions of uncertainty explain neon color spreading. Why groupings do not penetrate occluding objects is explained, as are percepts of DaVinci stereopsis, the Koffka-Benussi and Kanizsa-Minguzzi rings, and pictures of graffiti artists and Mooney faces. The property of analog coherence is achieved by laminar neocortical circuits. Variations of a shared canonical laminar circuit have explained data about vision, speech, and cognition. The FACADE theory of 3D vision and figure-ground separation explains much more data than a Bayesian model can. The same cortical process that assures consistency of boundary and surface percepts, despite their complementary laws, also explains how figure-ground separation is triggered. It is also explained how cortical areas V2 and V4 regulate seeing and recognition without forcing all occluders to look transparent.

A Theory of Illusory Lightness and Transparency in Monocular and Binocular Images: The Role of Contour Junctions

Perception ◽  
1997 ◽  
Vol 26 (4) ◽  
pp. 419-453 ◽  
Author(s):  
Barton L Anderson
Keyword(s):  
Illumination Change ◽  
Discontinuous Change ◽  
Illusory Contours ◽  
Contrast Polarity ◽  
Color Spreading ◽  
Transparent Surface ◽  
Neon Color Spreading ◽  
Lower Contrast

A theory of illusory transparency and lightness is described for monocular and binocular images containing X-, T- and I-contour junctions. This theory asserts that the geometric and luminance relationships of contour junctions induce illusory transparency and lightness percepts by causing a phenomenal scission of a homogenous luminance into multiple contributions. Specifically, it is argued that a discontinuous change in contrast along aligned contours that preserve contrast polarity induces a scission of the lower contrast region into a near-transparent surface or an illumination change, and a more distant surface that continues behind this near layer. This scission is assumed to cause changes in perceived lightness and/or surface opacity. Discontinuous changes in contrast along contours also are assumed to induce end-cut illusory contours that run roughly perpendicular to the inducing orientation of the contour, both monocularly and binocularly. Binocular illusory contours are shown to be caused by the presence of unmatchable contour terminators. It is argued that the presented theory can provide a unified account of a variety of monocular and binocular illusions that induce uniform transformations in perceived lightness, including neon-color spreading, the Munker – White illusion, Benary's illusion, and illusory monocular and binocular transparency.

Flank Transparency: The Effects of Gaps, Line Spacing, and Apparent Motion

Perception ◽  
10.1068/p3410 ◽  
2002 ◽  
Vol 31 (9) ◽  
pp. 1073-1092 ◽  
Author(s):  
Daniel Wollschläger ◽  
Antonio M Rodriguez ◽  
Donald D Hoffman
Keyword(s):  
Apparent Motion ◽  
Spatial Extent ◽  
Illusory Contours ◽  
Spreading Effect ◽  
Color Spreading ◽  
Line Spacing ◽  
Neon Color Spreading

We analyze the properties of a dynamic color-spreading display created by adding narrow colored flanks to rigidly moving black lines where these lines fall in the interior of a stationary virtual disk. This recently introduced display (Wollschläger et al, 2001 Perception30 1423–1426) induces the perception of a colored transparent disk bounded by strong illusory contours. It provides a link between the classical neon-color-spreading effect and edge-induced color spreading as discussed by Pinna et al (2001 Vision Research41 2669–2676). We performed three experiments to quantitatively study (i) the enhancing influence of apparent motion; (ii) the degrading effect of small spatial discontinuities (gaps) between lines and flanks; and (iii) the spatial extent of the color spreading. We interpret the results as due to varying degrees of objecthood of the dynamically specified disk: increased objecthood leads to increased surface visibility in both contour and color.

Insect perception of illusory contours

1992 ◽  
Vol 337 (1279) ◽  
pp. 59-64 ◽  
Keyword(s):  
Human Visual System ◽  
Illusory Contour ◽  
Optic Lobe ◽  
Insect Vision ◽  
Local Contrast ◽  
Fault Line ◽  
Illusory Contours ◽  
Striped Pattern ◽  
Processing Power ◽  
As If

The human visual system sees an illusory contour where there is a fault line across a regular striped pattern. We demonstrate that bees respond as if they see the same illusory contour. There is also a type of neuron in the lobula of the dragonfly optic lobe which responds directionally to motion of the illusory contour as if to an edge or line. Apparently insects have a mechanism that sees illusory contours and therefore assists in the demarcation of edges and objects at places where local contrast falls to zero at an edge, or where one textured object partially obscures another. These results suggest that insect vision, although spatially crude and low in processing power, sees separate objects by similar mechanisms to our own.

An Illusory Contour Can Facilitate Visually Induced Self-Motion Perception

2018 ◽  
Vol 31 (8) ◽  
pp. 715-727
Author(s):  
Shinji Nakamura ◽  
Shin’ya Takahashi
Keyword(s):  
Motion Perception ◽  
Illusory Contour ◽  
Uniform Motion ◽  
Horizontal Line ◽  
Illusory Contours ◽  
End Points ◽  
Line Segments ◽  
Illusory Perception ◽  
Vertically Aligned ◽  
Self Motion

Abstract Uniform motion of a visual stimulus induces an illusory perception of the observer’s self-body moving in the opposite direction (vection). The present study investigated whether vertical illusory contours can affect horizontal translational vection using abutting-line stimulus. The stimulus consisted of a number of horizontal line segments that moved horizontally at a constant speed. A group of vertically aligned segments created a ‘striped column’, while line segments in adjoining columns were shifted vertically to make a slight gap between them. In the illusory contour condition, the end points of the segments within the column were horizontally aligned to generate vertical illusory contours. In the condition with no illusory contour, these end points were not aligned within the column so that the illusory contour was not perceived. In the current study, 11 participants performed this experiment, and it was shown that stronger vection was induced in the illusory contour condition than in the condition with no illusory contour. The results of the current experiment provide novel evidence suggesting that non-luminance-defined visual features have a facilitative effect on visual self-motion perception.

Contour Interaction in Visual Space

1978 ◽  
Vol 22 (1) ◽  
pp. 74-77
Author(s):  
Robert Fox
Keyword(s):  
Visual Processing ◽  
Visual Masking ◽  
Random Element ◽  
Visual Space ◽  
Depth Information ◽  
Implicit Assumption ◽  
Depth Position ◽  
Series Of Experiments ◽  
Contour Interaction ◽  
Inhibitory Interactions

Virtually all the extensive research on inhibitory interactions among adjacent visual stimuli seen in such phenomena as simultaneous contrast and visual masking have employed situations in which the interacting stimulus elements occupy the same depth plane, i.e., the z-axis values are the same, in deference to the implicit assumption that processing of depth information occurs only after the visual processing of contour information is completed. But there are theoretical reasons and some data suggesting that the interactions among contours depend critically upon their relative positions in depth—interactions may not occur if the stimulus elements occupy different depth positions. The extent to which the metacontrast form of visual masking is dependent upon depth position was investigated in a series of experiments that used stereoscopic contours formed from random-element stereograms as test and mask stimuli. The random-element stereogram generation system permitted large variations in depth to be made without introducing confounding changes in proximal stimulation. The main results are 1) separation of test and mask stimuli in depth substantially reduces masking, and 2) when more than one stimulus is in visual space the stimulus that either appears first or appears closer to the observer receives preferential processing by the visual system.

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