Fluorescence and Gray Content of Surface Colors

Evans, R. M.

doi:10.1364/josa.49.001049

Cited by 53 publications

(35 citation statements)

References 8 publications

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“…This seems to be a general finding in luminosity threshold experiments. Other work using achromatic stimuli (Bonato & Gilchrist, 1994 and chromatic stimuli (Evans, 1959;Speigle & Brainard, 1996) has exhibited a high degree of variability.…”

Section: Resultsmentioning

confidence: 99%

The effects of figure/ground, perceived area, and target saliency on the luminosity threshold

Bonato

Cataliotti

2000

Perception & Psychophysics

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Observers adjusted the luminance of a target region until it began to appear self-luminous, or glowing. In Experiment 1, the target was either a face-shaped region (figure) or a non-face-shaped region (ground) of identical area that appeared to be the face's background. In Experiment 2, the target was a square or a trapezoid of identical area that appeared as a tilted rectangle. In Experiment 3, the target was a square surrounded by square, circular, or diamond-shaped elements. Targets that (1) were perceived as figures, (2) were phenomenally small in area, or (3) did not group well with other elements in the array because of shape appeared self-luminous at significantly lower luminance levels. These results indicate that like lightness perception, the luminosity threshold is influenced by perceptual organization and is not based on low-level retinal processes alone.

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Section: Resultsmentioning

confidence: 99%

The effects of figure/ground, perceived area, and target saliency on the luminosity threshold

Bonato

Cataliotti

2000

Perception & Psychophysics

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“…Instead, they appear to be self-luminous. [2][3][4][5][6][7][8][9][10][11][12] Indeed, for any viewing context, colored stimuli at most chromaticities can be varied in luminance so that they appear either as surfaces (at low luminances) or as self-luminous objects (at high luminances). We refer to the luminance at which the mode of appearance changes as the luminosity threshold.…”

Section: Introductionmentioning

confidence: 99%

Luminosity thresholds: effects of test chromaticity and ambient illumination

Speigle

Brainard

1996

J. Opt. Soc. Am. A

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Color constancy is often modeled on the assumption that color appearance in natural scenes is a function of the visual system's estimates of surface reflectance. Some stimuli, however, do not look like illuminated surfaces. Instead, they appear to be self-luminous. We hypothesized that the appearance of luminosity occurs when the visual system estimates a reflectance spectrum that is outside the gamut of physically realizable surfaces. To test this idea, we measured luminosity thresholds as a function of stimulus chromaticity and illuminant spectral power distribution. Observers adjusted the luminance of a test patch until it just appeared selfluminous. The test patch was spot illuminated by a computer-controlled projection colorimeter viewed in an experimental room lit diffusely by computer-controlled theater lamps. Luminosity thresholds were determined for a number of test patch chromaticities under five experimental illuminants. The luminosity thresholds define a surface in color space. The shape of this surface depends on the illuminant. We were able to describe much of the luminosity threshold variation with a simple model whose parameters define an equivalent illuminant. In the context of our model, the equivalent illuminant may be interpreted as the illuminant perceived by the observer. As part of our model calculations we generalized the classic notion of optimal stimuli by incorporating linear-model constraints. Given the equivalent illuminant, the model predicts that a patch will appear self-luminous when it is not consistent with any physically realizable surface seen under that illuminant. In addition, we show that much of the variation of the equivalent illuminant with the physical illuminant can be modeled with a simple linearity principle. The fact that our model provides a good account of our data extends the physics-based approach to judgments of self-luminosity. This in turn might be taken as support for the notion that the visual system has internalized the physics of reflectance.

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“…As group data seems to be necessary to label the second dimension, it seemed unnecessary to use the exhausting procedure of Experiment I. Therefore, a simpler method (described below), adapted from Evans (1959), was adopted.…”

Section: Resultsmentioning

confidence: 99%

The psychological relationship between lightness and saturation

Davidoff

1974

Perception & Psychophysics

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Lightness and saturation, though independent in a physical sense, have often been seen to be psychologically related. The first experiment uses a multidimensional scaling technique to again verify this nonindependence for untrained as. A further experiment, using a matching technique, quantifies this relationship, giving the extent of the error in lightness for varying levels of saturation. This relationship is found to be independent of hue if saturation is measured by the colorimetric purity of the hue. Errors in value (lightness on the Munsell system) were found to be linearly related to colorimetric purity.

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Fluorescence and Gray Content of Surface Colors

Cited by 53 publications

References 8 publications

The effects of figure/ground, perceived area, and target saliency on the luminosity threshold

The effects of figure/ground, perceived area, and target saliency on the luminosity threshold

Luminosity thresholds: effects of test chromaticity and ambient illumination

The psychological relationship between lightness and saturation

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