scholarly journals Why is the tilt after-effect selective to local but not global luminance-contrast polarity?

2013 ◽  
Vol 13 (9) ◽  
pp. 712-712
Author(s):  
E. Gheorghiu ◽  
J. Bell ◽  
F. A. A. Kingdom
Keyword(s):  
Luminance Contrast ◽  
Contrast Polarity ◽  
After Effect

scholarly journals Surface and motion integration determined by luminance contrast polarity

2004 ◽  
Vol 4 (8) ◽  
pp. 888-888
Author(s):  
Y. Su ◽  
T. Leng ◽  
Z. J. He
Keyword(s):  
Luminance Contrast ◽  
Contrast Polarity ◽  
Motion Integration

Geometrical Errors Are the Cost of Maintaining the Luminance Contrast Polarity

2017 ◽  
Author(s):  
Sergio Roncato
Keyword(s):  
Luminance Contrast ◽  
Contrast Polarity ◽  
Geometrical Errors ◽  
Visual Completion ◽  
Visual Organization ◽  
Preferential Rule ◽  
The Cost

The visual completion is the result of the integration of fragmented contours. The contrast polarity (or contrast sign) may affect this interpolation by strengthening the completion in a direction where the contrast polarity is preserved. This chapter illustrates some manifestations of these phenomena: the alteration of the alignment of the visual units and the illusory tilt of more complex visual organization. The occurrence of basic distorting effects underlying classic illusions—such as the Frazer illusion—is discussed. It is noted that the role of the contrast polarity rule in representing a “preferential” rule does not preclude other possibilities, such as edges completion, although it renders the contour detectable to a lesser degree.

scholarly journals The butterfly Papilio xuthus detects visual motion using chromatic contrast

2015 ◽  
Vol 11 (10) ◽  
pp. 20150687 ◽  
Author(s):  
Finlay J. Stewart ◽  
Michiyo Kinoshita ◽  
Kentaro Arikawa
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Luminance Contrast ◽  
Head Movements ◽  
Motion Vision ◽  
Measuring Head ◽  
Chromatic Contrast ◽  
Contrast Polarity ◽  
Papilio Xuthus ◽  
Colour Patterns

Many insects’ motion vision is achromatic and thus dependent on brightness rather than on colour contrast. We investigate whether this is true of the butterfly Papilio xuthus , an animal noted for its complex retinal organization, by measuring head movements of restrained animals in response to moving two-colour patterns. Responses were never eliminated across a range of relative colour intensities, indicating that motion can be detected through chromatic contrast in the absence of luminance contrast. Furthermore, we identify an interaction between colour and contrast polarity in sensitivity to achromatic patterns, suggesting that ON and OFF contrasts are processed by two channels with different spectral sensitivities. We propose a model of the motion detection process in the retina/lamina based on these observations.

A Test for Contrast-Polarity Selectivity in the Tilt Aftereffect

Perception ◽  
1979 ◽  
Vol 8 (5) ◽  
pp. 523-528 ◽  
Author(s):  
Svein Magnussen ◽  
Wolfgang Kurtenbach
Keyword(s):  
Luminance Contrast ◽  
Tilt Aftereffect ◽  
Contrast Polarity

The tilt aftereffect (TAE) was studied with adapting and test stimuli consisting of black or white bars (experiment 1), and of luminance edges (experiment 2). Both experiments failed to demonstrate selectivity of the TAE to the polarity of luminance contrast.

scholarly journals The effect of nearby luminance contrast polarity on color boundary localization

1995 ◽  
Vol 35 (19) ◽  
pp. 2767-2771 ◽  
Author(s):  
Harold H. Greene ◽  
James M. Brown
Keyword(s):  
Luminance Contrast ◽  
Contrast Polarity

scholarly journals Dependence of perceptual saccadic suppression on peri-saccadic image flow properties and luminance contrast polarity

2021 ◽  
Vol 21 (9) ◽  
pp. 2282
Author(s):  
Matthias Philipp Baumann ◽  
Saad Idrees ◽  
Thomas Münch ◽  
Ziad Hafed
Keyword(s):  
Luminance Contrast ◽  
Saccadic Suppression ◽  
Flow Properties ◽  
Contrast Polarity ◽  
Image Flow

scholarly journals Dependence of perceptual saccadic suppression on peri-saccadic image flow properties and luminance contrast polarity

2021 ◽  
Vol 21 (5) ◽  
pp. 15
Author(s):  
Matthias P. Baumann ◽  
Saad Idrees ◽  
Thomas A. Münch ◽  
Ziad M. Hafed
Keyword(s):  
Luminance Contrast ◽  
Saccadic Suppression ◽  
Flow Properties ◽  
Contrast Polarity ◽  
Image Flow

Illusory-Contour Formation Affected by Luminance Contrast Polarity

Perception ◽  
1998 ◽  
Vol 27 (3) ◽  
pp. 313-335 ◽  
Author(s):  
Zijiang J He ◽  
Teng Leng Ooi
Keyword(s):  
Illusory Contour ◽  
Necker Cube ◽  
Spatial Separation ◽  
Luminance Contrast ◽  
Amodal Completion ◽  
Illusory Contours ◽  
Contrast Polarity ◽  
Spatial Alignment ◽  
Occluded Objects ◽  
Partially Occluded

We report a new type of illusory contour (Illusory-O) whose formation is contingent upon the contrast polarity of its juxtaposed inducing elements being similar, ie both elements must either be positive or negative in contrast sign. To test the hypothesis that this contingency is primarily dictated by factors that determine amodal surface completion (occlusion) between the inducing elements we conducted a series of experiments employing known spatial properties of the amodal completion mechanism, to show that spatial conditions unfavorable to occlusion lead to a concurrent weakening of the Illusory-O formation. For instance, we found that when the juxtaposed inducing elements (solid rectangles) were spatially misaligned, or when their spatial separation increased, our observers rated the perception of the Illusory-O as reduced. We also showed that, in addition to using solid-form inducing elements, the Illusory-O can be induced by line terminals, as long as these lines respect the requirements of the amodal completion mechanism such as similar contrast polarity and spatial alignment. Then we demonstrated that the role of the amodal completion mechanism is not limited to our particular arrangement of inducing elements by showing that the formation of the illusory Necker cube also relies on similar contrast polarity. Finally, to explain why some illusory contours like the Illusory-O are dependent on contrast polarity while others (eg Kanizsa square) are not, we propose that the key rests upon the visual system's presumption of occlusion. That is, in forming the illusory contour, if the visual system infers that it is a byproduct of the inducing elements being occluded, then having inducing elements of similar contrast polarity becomes a prerequisite. This assumption can be traced to the occurrence in the real world where partially occluded objects usually have visible parts (on both ends) with similar contrast polarity. Along this line of thinking, we suggest a plausible neural circuitry that may be implemented to form both contrast polarity sensitive and insensitive types of illusory contours.

Features of the Selectivity for Contrast Polarity in Contour Integration Revealed by a Novel Tilt Illusion

Perception ◽  
10.1068/p6897 ◽  
2011 ◽  
Vol 40 (11) ◽  
pp. 1357-1375 ◽  
Author(s):  
Stefano Guidi ◽  
Oronzo Parlangeli ◽  
Sandro Bettella ◽  
Sergio Roncato
Keyword(s):  
Luminance Contrast ◽  
Opposite Polarity ◽  
Contour Integration ◽  
Good Continuation ◽  
Distance Threshold ◽  
Binding Effect ◽  
Tilt Illusion ◽  
Contrast Polarity ◽  
The One

We studied a novel illusion of tilt inside checkerboards due to the role of contrast polarity in contour integration. The preference for binding of oriented contours having same contrast polarity, over binding of opposite polarity ones (CP rule), has been used to explain several visual illusions. In three experiments we investigated how the binding effect is influenced by luminance contrast value, relatability of contour elements, and distance among them. Experiment 1 showed that the effect was indeed present only when the CP rule was satisfied, and found it to be stronger when the luminance contrast values of the elements are more similar. In experiment 2 the illusion was reported only with relatable edges, and its strength was modulated by the degree of relatability. The CP-rule effectiveness, thus, seems to depend on good continuation. The intensity of contrast polarity signals propagating from an oriented contour might be the less intense, the more its direction deviates from linearity. In experiment 3 we estimated the distance threshold and found it to be smaller than the one found for other illusions, arising with collinear fragments. This seems to show that the reach of the contrast polarity signal inside the association field of a contour unit is shorter along non-collinear orientations than along collinear ones.

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