Cardinal directions of color space

Krauskopf, John; Williams, David R.; Heeley, D.W.

doi:10.1016/0042-6989(82)90077-3

Cited by 692 publications

(460 citation statements)

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“…two of the components of the stimulus-vector are zero) are called cardinal directions. 86 The cardinal directions of the chromatic mechanisms, plotted in the CIE1931 chromaticity diagram, are shown in figure 21. An example of the appearance of the gratings along such directions is shown in figure 22 (with fy=0).…”

Section: The Chromatic Contrast Sensitivity Functions: Ccsfsmentioning

confidence: 99%

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Dı́ez-Ajenjo

Capilla

2010

Journal of Optometry

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We review the psychophysics of the spatio-temporal contrast sensitivity in the cardinal directions of the colour space and their correlation with those neural characteristics of the visual system that limit the ability to perform contrast detection or pattern-resolution tasks. We focus our attention particularly on the influence of luminance level, spatial extent and spatial location of the stimuli -factors that determine the characteristics of the physiological mechanisms underlying detection. Optical factors do obviously play a role, but we will refer to them only briefly. Contrast sensitivity measurements are often used in clinical practice as a method to detect, at their early stages, a variety of pathologies affecting the visual system, but their usefulness is very limited due to several reasons. We suggest some considerations about stimuli characteristics that should be taken into account in order to improve the performance of this kind of measurement. RESUMENSe revisa la psicofísica sobre la sensibilidad al contraste con patrones espacio-temporales en las direcciones cardinales del espacio de color y su relación con las características neuronales del sistema visual que limitan la habilidad para realizar una tarea de detección de contraste o de resolución de patrones. La atención se centra especialmente en la influencia del nivel de luminancia, el tamaño y la localización espacial de los estímulos, en la medida que estos son los factores más importantes que determinan las características de los mecanismos fisiológicos que median la detección. Obviamente, los factores ópti-cos también juegan un papel en el conjunto del sistema visual, pero nos referiremos a ellos sólo brevemente. Las medidas de sensibilidad al contraste son a menudo usadas en clínica como método para detectar, en un estado temprano, una amplia variedad de patologías del sistema visual, pero su utilidad en la práctica es bastante limitada por diferentes razones. Sugerimos que ciertas consideraciones sobre los estímulos deberían ser tenidas en cuenta si se quiere mejorar las prestaciones actuales de este tipo de medidas. (J Optom 2010;3:2-19 ©2010 Consejo General de Colegios de Ópticos-Optometristas de España) PALABRAS CLAVE: sensibilidad al contraste; patrones espacio-temporales; espacio de color; direcciones cardinales; caminos visuales. INTRODUCTIONDuring the last three decades, the possibility of early detection of a variety of pathologies affecting the visual system by means of the measurement of spatial and temporal contrast sensitivity functions -CSFs-has been thoroughly explored. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] (Burr D, et al. IOVS 2003;44: ARVO E-Abstract 3193). It has been shown, however, that the usefulness of these functions is rather limited in practice, for several reasons. In the first place, measurements are often limited to the fovea, whilst anatomical damage and functional loss frequently begin outside this region [see, for example, F. Rowe's book 17 ]. In fact, different perimetry technique...

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Section: The Chromatic Contrast Sensitivity Functions: Ccsfsmentioning

confidence: 99%

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Dı́ez-Ajenjo

Capilla

2010

Journal of Optometry

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“…The attenuation of human flicker sensitivity, consequent to adaptation, is evident in both behavioral (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and neural (9,23,24) response measures, but its frequency dependence has never been assessed systematically. Here we measure the reduction in flicker sensitivity after prolonged exposure, or adaptation, to both luminance and chromatic flicker across a wide range of frequencies.…”

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confidence: 99%

“…Here we pursue these questions through an experimental design that exploits, as a functional landmark, the known process of flicker adaptation, by which flicker sensitivity of an observer is attenuated after prolonged exposure to flickering lights (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). The attenuation of human flicker sensitivity, consequent to adaptation, is evident in both behavioral (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and neural (9,23,24) response measures, but its frequency dependence has never been assessed systematically.…”

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Adaptation from invisible flicker

Shady

MacLeod

Fisher

2004

Proc. Natl. Acad. Sci. U.S.A.

102

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Human ability to resolve temporal variation, or flicker, in the luminance (brightness) or chromaticity (color) of an image declines with increasing frequency and is limited, within the central visual field, to a critical flicker frequency of Ϸ50 and 25 Hz, respectively. Much remains unknown about the neural filtering that underlies this frequency-dependent attenuation of flicker sensitivity, most notably the number of filtering stages involved and their neural loci. Here we use the process of flicker adaptation, by which an observer's flicker sensitivity is attenuated after prolonged exposure to flickering lights, as a functional landmark. We show that flicker adaptation is more sensitive to high temporal frequencies than is conscious perception and that prolonged exposure to invisible flicker of either luminance or chromaticity, at frequencies above the respective critical flicker frequency, can compromise our visual sensitivity. This suggests that multiple filtering stages, distributed across retinal and cortical loci that straddle the locus for flicker adaptation, are involved in the neural filtering of high temporal frequencies by the human visual system.

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“…Empirical evidence shows that contrast sensitivity functions for stimuli containing achromatic, L/M-opponent and S-opponent modulations take differing forms, reflecting differences in the properties of the mechanisms that convey each class of signal (Mullen 1985). Adapting stimuli that isolate one of the opponent mechanisms do not alter visual threshold measurements taken along the orthogonal opponent direction (Bradley et al 1988;Krauskopf and Gegenfurtner 1992;Krauskopf et al 1982).Differences in performance have been observed in shape discrimination tasks, measuring the radial modulation threshold for discrimination between circular and non-circular stimuli matched in multiples of stimulus detection threshold. The Sopponent system was found to perform worst, followed by the L/M-opponent system and the achromatic system (Mullen and Beaudot 2002).…”

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The L/M-Opponent Channel Provides a Distinct and Time-Dependent Contribution towards Visual Recognition

Vincent

Gobet²,

Parker

et al. 2010

Perception

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The visual pathway has been successfully modelled as containing separate channels consisting of one achromatically opponent mechanism and two chromatically opponent mechanisms. However, little is known about how time affects the processing of chromatic information. Parametrically defined objects were generated. Reduced colour objects were interleaved with full-colour objects and measures of recognition performance (d-prime [d']) were compared using the continuous serial recognition paradigm. Measures were taken at multiple delay intervals (1 s, 4 s, 7 s, and 10 s). When chromatic variations were removed, recognition performance was impaired, but at the 1 s and 10 s intervals only. When luminance variations were removed, no impairment resulted. When only L/Mopponent modulations were removed, a deficit in performance was produced only at the 1 s and 10 s intervals, similar to the removal of chromatic variation. When only Sopponent modulations were removed, no impairment was observed. The results suggest that the L/M-opponent pathway provides a specialized contribution to visual recognition, but that its effect is modulated by time. A three-stage process model is proposed to explain the data. We wanted to examine whether constraints placed on a single dimension (colour) modulated VSTM performance. Understanding VSTM and its role in recognition ability is important as it has the potential to aid normal and deficient behaviour. In this study, the contribution of colour to human visual recognition performance was examined to ascertain the effect of time on removing variation from object stimuli along one or two dimensions of the 3D colour space. The visual pathway has been successfully modelled as containing separate channels consisting of one achromatically opponent mechanism and two chromatically opponent mechanisms (Buchsbaum and Gottschalk 1983). Empirical evidence shows that contrast sensitivity functions for stimuli containing achromatic, L/M-opponent and S-opponent modulations take differing forms, reflecting differences in the properties of the mechanisms that convey each class of signal (Mullen 1985). Adapting stimuli that isolate one of the opponent mechanisms do not alter visual threshold measurements taken along the orthogonal opponent direction (Bradley et al 1988;Krauskopf and Gegenfurtner 1992;Krauskopf et al 1982).Differences in performance have been observed in shape discrimination tasks, measuring the radial modulation threshold for discrimination between circular and non-circular stimuli matched in multiples of stimulus detection threshold. The Sopponent system was found to perform worst, followed by the L/M-opponent system and the achromatic system (Mullen and Beaudot 2002).Imaging studies using functional magnetic resonance imaging (fMRI) have shown how extremely sensitive the visual system is to chromatic modulations of low In this study, we examined how time affects the relative contribution of the L/M-opponent and S-opponent modulations to visual recognition. We were interested in the d...

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Cardinal directions of color space

Cited by 692 publications

References 14 publications

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Spatio-temporal Contrast Sensitivity in the Cardinal Directions of the Colour Space. A Review

Adaptation from invisible flicker

The L/M-Opponent Channel Provides a Distinct and Time-Dependent Contribution towards Visual Recognition

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