Conjunctions of colour, luminance and orientation: the role of colour and luminance contrast on saliency and proximity grouping in texture segregation

Segregation of textures on the basis of orientation differences between texture elements is achieved even when these texture elements differ from their surround only by colour (McIlhagga et al, 1990 Vision Research30 489 – 495). This finding seems to contradict the assumption that colour and orientation are extracted in separate feature maps (eg Treisman and Sato, 1990 Journal of Experimental Psychology: Human Perception and Performance16 459 – 478). To examine whether colour information is evaluated in parallel in different processing streams for the assessment of hue and form, we tested whether texture elements can be segregated if they differ only by specific conjunctions of colour and orientation; texture elements consisted of crosses with their two crossing lines differing in colour. Texture elements defining figure and background had the same coloured composition but the conjunction of colour with the two crossing lines was reversed. Different colour combinations were tested under various luminance contrast conditions, irrespective of the colour combination, segmentation was achieved as long as the two crossing lines of the texture elements differed in luminance. If, however, the different colours of the two crossing lines were approximately equiluminant, segmentation was reduced or impossible. Thus, subjects were able to use for texture segregation conjunctions between luminance and orientation but not between colour and orientation. Our results suggest that colour cannot be associated selectively with differently oriented components of the same texture element. This supports the hypothesis that colour contrast is used in parallel by different processing streams to assess the orientation and hue of contours and reveals limitations in the selectivity with which features are subsequently bound together.

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Task-Dependence of Texture-Segregation-Specific VEP Components

Perception ◽

10.1068/v970278 ◽

1997 ◽

Vol 26 (1_suppl) ◽

pp. 267-267

Author(s):

T Meigen

Keyword(s):

Visual Evoked Potential ◽

Evoked Potential ◽

Normal Subjects ◽

Luminance Contrast ◽

Auditory Stimuli ◽

Cognitive Responses ◽

Texture Segregation ◽

Task Dependence ◽

Additional Task ◽

Temporal Overlap

Recently, texture-segregation-specific components have been isolated in the human visual evoked potential (tsVEPs). As tsVEPs are characterised by a negative peak near 200 ms they occur between luminance-contrast responses (P100) and cognitive responses (P300). The aim of this study was to estimate the temporal overlap of tsVEPs and cognitive VEP components by directing a task to either visual or auditory stimuli. Eight visually normal subjects participated in the experiment. Horizontal and vertical line segments were arranged to yield either an ‘orientation chequerboard’ stimulus or two fields with homogeneous orientations. As auditory stimuli, two tones with different pitches were presented through headphones. Auditory and visual stimuli were temporally uncorrelated, which allowed off-line isolation of VEPs and AEPs by appropriate averaging from the same raw data. VEPs and AEPs were recorded from an array of 13 electrodes ranging from frontal to occipital positions. tsVEPs were isolated under two conditions, where the subjects detected the presence of (a) the orientation chequerboard, or (b) the higher pitch by pressing a button. It was found that (1) tsVEPs could be isolated under both tasks; (2) tsVEPs were strongly modulated by the task; (3) the task-specific modulation occurred in the same time domain as the tsVEP itself, but showed a different topography; (4) AEPs were less modulated by the task. The data suggest that an additional task concerning the gradient content of texture stimuli may modulate the resulting tsVEPs. This may partially account for the interindividual variability in recent tsVEP data, as a comparable task may be introduced tacitly by the subjects.

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Reduced Cognitive Control of a Visually Bistable Image in Schizophrenia

Journal of the International Neuropsychological Society ◽

10.1017/s1355617711000245 ◽

2011 ◽

Vol 17 (3) ◽

pp. 551-556 ◽

Cited By ~ 8

Author(s):

Ryan McBain ◽

Daniel J. Norton ◽

Jejoong Kim ◽

Yue Chen

Keyword(s):

Cognitive Control ◽

Sensory Input ◽

Necker Cube ◽

Cognitive Remediation ◽

Luminance Contrast ◽

Contrast Condition ◽

Cube Plane ◽

Sensory Features ◽

Visual Modulation

AbstractSchizophrenia is associated with the inability to control and coordinate thoughts, actions, and perceptions. In conventional assessments of cognitive control, multiple sensory features of stimuli are concomitantly manipulated, introducing a confounding role of bottom-up perceptual information. To overcome this difficulty, we used an ambiguous visual stimulus (Necker cube), which allowed measurement of cognitive control with constant sensory input. Subjects (20 patients, 20 controls) were asked to control their perception of a transparent Necker cube by keeping a designated plane at the front or back of the stimulus, the position of which is perceptually bistable. Patients were highly deficient at controlling their perception of the cube. When a visual feature (the luminance contrast between a designated cube plane and the other planes) was systematically manipulated, an interaction was found whereby schizophrenia patients no longer under-performed on the highest contrast condition. These results show patients’ impairment of controlling perception in the absence of visual modulation and suggest the potential utility of perceptually based approaches to cognitive remediation in schizophrenia. (JINS, 2011, 551–556)

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Geometrical Errors Are the Cost of Maintaining the Luminance Contrast Polarity

10.1093/acprof:oso/9780199794607.003.0032 ◽

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.

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Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2010.0204 ◽

2011 ◽

Vol 366 (1565) ◽

pp. 734-741 ◽

Cited By ~ 37

Author(s):

Vincenzo Pignatelli ◽

Shelby E. Temple ◽

Tsyr-Huei Chiou ◽

Nicholas W. Roberts ◽

Shaun P. Collin ◽

...

Keyword(s):

Target Detection ◽

Polarized Light ◽

Luminance Contrast ◽

Polarization Sensitivity ◽

Prey Detection ◽

Free Swimming ◽

Detection Mechanism ◽

Set Up ◽

Polarization Of Light

Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to free-swimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast.

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Central-Cue Discriminability Modulates Object-Based Attention by Influencing Spatial Attention

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000135 ◽

2012 ◽

Vol 59 (3) ◽

pp. 132-137 ◽

Cited By ~ 2

Author(s):

Morris Goldsmith ◽

Menahem Yeari

Keyword(s):

Spatial Attention ◽

Luminance Contrast ◽

Attentional Focus ◽

Perceptual Representation ◽

Object Representations ◽

Attentional Deployment ◽

Object Based ◽

Target Locations ◽

Central Arrow

The role of central-cue discriminability in modulating object-based effects was examined using Egly, Driver, and Rafal’s (1994) “double-rectangle” spatial cueing paradigm. Based on the attentional focusing hypothesis (Goldsmith & Yeari, 2003), we hypothesized that highly discriminable central-arrow cues would be processed with attention spread across the two rectangles (potential target locations), thereby strengthening the perceptual representation of these objects so that they influence the subsequent endogenous deployment of attention, yielding object-based effects. By contrast, less discriminable central-arrow cues should induce a more narrow attentional focus to the center of the display, thereby weakening the rectangle object representations so that they no longer influence the subsequent attentional deployment. Central-arrow-cue discriminability was manipulated by size and luminance contrast. The results supported the predictions, reinforcing the attentional focusing hypothesis and highlighting the need to consider central-cue discriminability when designing experiments and in comparing experimental results.

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The Role of the Background: Texture Segregation and Figure—Ground Segmentation

Vision Research ◽

10.1016/0042-6989(96)00045-4 ◽

1996 ◽

Vol 36 (18) ◽

pp. 2815-2826 ◽

Cited By ~ 19

Author(s):

GIOVANNI CAPUTO

Keyword(s):

Texture Segregation ◽

Background Texture ◽

Ground Segmentation

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Color tuning of neurons in face patches of macaque inferior temporal cortex

10.1101/863779 ◽

2019 ◽

Author(s):

Marianne Duyck ◽

Tessa J. Gruen ◽

Lawrence Y. Tello ◽

Serena Eastman ◽

Joshua Fuller-Deets ◽

...

Keyword(s):

Second Harmonic ◽

Temporal Cortex ◽

Luminance Contrast ◽

Macaque Monkey ◽

Inferior Temporal Cortex ◽

Color Tuning ◽

Quantitative Measurements ◽

Cone Activity ◽

Insight Into

Previous work has shown that under viewing conditions that break retinal mechanisms for color, one class of objects appears paradoxically colored: faces, and they look green. Interpreted within a Bayesian-observer framework, this observation makes the surprising prediction that face-selective neurons are sensitive to color and weakly biased for colors that elicit L>M cone activity (warm colors). We tested this hypothesis by measuring color-tuning responses of face-selective cells in alert macaque monkey, using fMRI-guided microelectrode recording of the middle and anterior face patches and carefully color-calibrated stimuli. The population of face-selective neurons showed significant color tuning when assessed using images that preserved the luminance contrast relationships of the original face photographs. A Fourier analysis of the color-tuning responses uncovered two components. The first harmonic was biased towards the L>M colors, consistent with the prediction. Interestingly, the second harmonic aligned with the S-cone cardinal axis, which may relate to the computation of animacy by IT cells.SignificanceThe results provide the first quantitative measurements of the color tuning properties of face-selective neurons. The results provide insight into the neural mechanisms that could support the role of color in face perception.

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