scholarly journals Contrast normalization in colour vision: the effect of luminance contrast on colour contrast detection

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Kathy T. Mullen ◽  
Yeon Jin Kim ◽  
Mina Gheiratmand
Keyword(s):  
Colour Vision ◽  
Luminance Contrast ◽  
Contrast Detection ◽  
Colour Contrast ◽  
Contrast Normalization

scholarly journals Luminance contrast and colour contrast related errors in pseudoisochromatic plate identification

Eye ◽  
1997 ◽  
Vol 11 (5) ◽  
pp. 713-716
Author(s):  
Michael Wall ◽  
Paul B Donzis
Keyword(s):  
Luminance Contrast ◽  
Colour Contrast

Texture Segregation by Orientation Differences: Colour Sensitive but Not Hue Specific?

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 98-98
Author(s):  
U Leonards ◽  
W Singer
Keyword(s):  
Experimental Psychology ◽  
Human Perception ◽  
Luminance Contrast ◽  
Texture Element ◽  
Feature Maps ◽  
Texture Segregation ◽  
Colour Contrast

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.

Does L/M Cone Opponency Disappear in Human Periphery?

Perception ◽  
10.1068/p5374 ◽  
2005 ◽  
Vol 34 (8) ◽  
pp. 951-959 ◽  
Author(s):  
Kathy T Mullen ◽  
Masato Sakurai ◽  
William Chu
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Sine Wave ◽  
Human Vision ◽  
Peripheral Retina ◽  
Contrast Detection ◽  
Colour Contrast

We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a ‘sinring’, that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25–30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally.

Isoluminant Colour Contrast Does Not Fill in Surfaces

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 40-40
Author(s):  
B Dresp ◽  
C Wehrhahn
Keyword(s):  
Luminance Contrast ◽  
Opposite Polarity ◽  
The Other ◽  
Test Surface ◽  
Colour Contrast ◽  
Mixed Polarity ◽  
Polarity Condition ◽  
Matching Procedure ◽  
The Mean ◽  
Neurophysiological Basis

It has been suggested (Livingstone and Hubel, 1988 Science240 740 – 749) that the ‘colour-blind’ magnocellular pathways generate the neurophysiological basis of surfaces with illusory contours since the latter do not seem to be perceived in inducing configurations of a given colour which is isoluminant with regard to the colour of the background (equiluminant colour contrast). However, psychophysical data allowing us to assess the relative visibility of illusory surfaces in coloured stimuli with luminance contrast compared to configurations with equiluminant colour contrast are not yet available. We designed a colour-matching experiment where ten naive observers had to adjust the intensity of a red illusory surface so that it appeared to match the intensity of the red background. The configurations used were Kanizsa squares with green inducing elements, isoluminant or not with regard to the background. Isoluminance was assessed individually for each observer by means of a classical flicker test. A brightness-matching procedure was applied to configurations of achromatic inducers on a grey background. In this case, the inducers had either all the same contrast polarity (light), or both polarities (light and dark) within a given configuration. Luminance contrast in the achromatic configuration with only one polarity was the same as in the non-isoluminant colour condition. Luminance contrasts of light and dark inducers in the mixed-polarity condition were physically balanced. The results show that the mean point of subjective equality (PSE) of the test surface corresponds to the physical intensity of the background with equiluminant colour contrast only, indicating the absence of an apparent surface in this condition. This result supports the idea that magnocellular pathways in the human visual system mediate the neurophysiological genesis of illusory surfaces. In all the other stimulus conditions, the PSE does not correspond to the physical intensity of the background. Matching ‘errors’ are significantly stronger in the achromatic conditions, but, paradoxically, strongest in the condition with balanced contrasts of opposite polarity. This finding suggests that luminance contrast is not the only determinant of the perceived strength of illusory surfaces.

Neglect for low luminance contrast stimuli but not for high colour contrast stimuli

Neuroreport ◽  
1996 ◽  
Vol 7 (8) ◽  
pp. 1360-1364 ◽  
Author(s):  
Fabrizio Doricchi ◽  
Paola Angelelli ◽  
Maria De Luca ◽  
Donatella Spinelli
Keyword(s):  
Luminance Contrast ◽  
Colour Contrast ◽  
Low Luminance

scholarly journals Hue-selective elevation in luminance contrast detection threshold following adaptation to luminance-varying gabor patches

2010 ◽  
Vol 2 (7) ◽  
pp. 209-209
Author(s):  
J. L. Hardy ◽  
K. K. Valois
Keyword(s):  
Detection Threshold ◽  
Luminance Contrast ◽  
Contrast Detection

Colour Constancy in Goldfish—The Role of Surround Reflectance

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 52-52
Author(s):  
J Fritsch ◽  
C Neumeyer
Keyword(s):  
White Light ◽  
Colour Vision ◽  
Test Situation ◽  
Lateral Interactions ◽  
Colour Constancy ◽  
Colour Contrast ◽  
Behavioural Experiments ◽  
Deep Green ◽  
High Reflectance

Simultaneous colour contrast as well as colour constancy have been shown quantitatively for the goldfish. In behavioural experiments we investigated colour constancy in goldfish for green and purple colours. Two fish were trained with food rewards to select one of ten test-fields in hues ranging, in small steps of saturation, from deep green, through grey, to deep purple. In the training situation the whole disk was illuminated by white light, whereas in the test situation it was changed to green and purple light, respectively. The role of surround reflectance was investigated by presenting the test fields either on a black or on a white surround. With a black surround (low reflectance) in purple illumination the fish chose test fields that were more green than the training field indicating imperfect colour constancy. With a white surround (high reflectance), however, the fish chose testfields that were more purple. This ‘overcompensation’ indicates that a white surround induces a hue complementary to that of the illumination. A similar phenomenon is known as the Helson — Judd effect in human colour vision. For green illumination the phenomenon was similar. The effect could be decreased by reducing the white surround to small white annuli around the test fields. A decrease was also achieved by separating the white surround from the test fields by black annuli. Perfect colour constancy could thus be obtained with a certain size of a white surround as well as with a certain size of separation. We therefore assume that lateral interactions play an important role in colour constancy.

Proposed modification to the CAM16 colour appearance model to predict the simultaneous colour contrast effect

2019 ◽  
Vol 2019 (1) ◽  
pp. 190-194
Author(s):  
Yuechen Zhu ◽  
Ming Ronnier Luo
Keyword(s):  
Contrast Effect ◽  
Colour Vision ◽  
Appearance Model ◽  
Matching Method ◽  
Colour Contrast ◽  
Normal Colour ◽  
Proposed Modification ◽  
Colour Appearance

Experiments were carried out to investigate the simultaneous colour contrast effect on a self-luminous display using colour matching method. The goals of this study were to accumulate a new visual dataset and to extend CAM16 to predict the simultaneous colour contrast effect. Five coloured targets together with a neutral grey were studied. A total of 132 test/background combinations were displayed on a calibrated display. Twenty normal colour vision observers performed colour matching in the experiment. In total, 2,640 matches were accumulated. The data were used to accurately model the lightness and hue contrast results. The model was also successfully tested using two independent datasets.

Colour Pools, Brightness Pools, Assimilation, and the Spatial Resolving Power of the Human Colour-Vision System

Perception ◽  
1993 ◽  
Vol 22 (3) ◽  
pp. 343-351 ◽  
Author(s):  
Bernard Moulden ◽  
Fred Kingdom ◽  
Brian Wink
Keyword(s):  
Colour Vision ◽  
Vision System ◽  
Spatial Scales ◽  
Receptive Fields ◽  
Luminance Contrast ◽  
Resolving Power ◽  
Spatial Pooling ◽  
Infant Vision ◽  
Spatial Frequencies ◽  
Normal Colour

A stimulus is described that demonstrates the spatial pooling of colour information in the visual system. Chequerboards (or gratings) consisting of alternating squares (or stripes) of complementary colours become achromatic at particular spatial scales; such stimuli have been named ‘transchromatic’ stimuli. Colour pools are much larger than the receptive fields that respond to luminance contrast. Some measurements are described which form the basis for estimates of the size of the colour pools. The size of colour pools varies according to the colours involved. For red—cyan and green—magenta complementary pairs colour is pooled at spatial frequencies above about 7–8 cycles deg−1, implying pools whose diameter is around 8 min arc. For yellow—blue complementary pairs the corresponding figures are about 4 cycles deg−1 and 15 min arc. Some phenomena of normal colour vision, colour blindness, and the development of infant vision are discussed in the light of these findings.

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