No measured effect of a familiar contextual object on color constancy

Kanematsu, Erika; Brainard, David H.

doi:10.1002/col.21805

Cited by 16 publications

(12 citation statements)

References 39 publications

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“…At the same time, the images of scenes should still allow for controlled rendering of colors based on reflectances. Moreover, they should not contain color diagnostic objects because we also wanted to control for possible effects of memory colors on color constancy (Granzier & Gegenfurtner, 2012;Kanematsu & Brainard, 2013). Hence, the images used in the present study attempted to combine photorealism, the control of color rendering, and the absence of color diagnostic objects (cf.…”

Section: Methodsmentioning

confidence: 99%

Uncertainty of sensory signal explains variation of color constancy

et al. 2016

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Color constancy is the ability to recognize the color of an object (or more generally of a surface) under different illuminations. Without color constancy, surface color as a perceptual attribute would not be meaningful in the visual environment, where illumination changes all the time. Nevertheless, it is not obvious how color constancy is possible in the light of metamer mismatching. Surfaces that produce exactly the same sensory color signal under one illumination (metamerism) may produce utterly different sensory signals under another illumination (metamer mismatching). Here we show that this phenomenon explains to a large extent the variation of color constancy across different colors. For this purpose, color constancy was measured for different colors in an asymmetric matching task with photorealistic images. Color constancy performance was strongly correlated to the size of metamer mismatch volumes, which describe the uncertainty of the sensory signal due to metamer mismatching for a given color. The higher the uncertainty of the sensory signal, the lower the observers' color constancy. At the same time, sensory singularities, color categories, and cone ratios did not affect color constancy. The present findings do not only provide considerable insight into the determinants of color constancy, they also show that metamer mismatch volumes must be taken into account when investigating color as a perceptual property of objects and surfaces.

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Section: Methodsmentioning

confidence: 99%

Uncertainty of sensory signal explains variation of color constancy

et al. 2016

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“…• Memory color matches might be less sensitive to changes in viewing conditions and therefore be less representative [59], but see [60].…”

Section: Memory Color Matching (Mcm)mentioning

confidence: 99%

Study of chromatic adaptation using memory color matches, Part I: neutral illuminants

et al. 2017

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Twelve corresponding color data sets have been obtained using the long-term memory colors of familiar objects as target stimuli. Data were collected for familiar objects with neutral, red, yellow, green and blue hues under 4 approximately neutral illumination conditions on or near the blackbody locus. The advantages of the memory color matching method are discussed in light of other more traditional asymmetric matching techniques. Results were compared to eight corresponding color data sets available in literature. The corresponding color data was used to test several linear (von Kries, RLAB, etc.) and nonlinear (Hunt & Nayatani) chromatic adaptation transforms (CAT). It was found that a simple two-step von Kries, whereby the degree of adaptation D is optimized to minimize the DEu'v' prediction errors, outperformed all other tested models for both memory color and literature corresponding color sets, whereby prediction errors were lower for the memory color sets. The predictive errors were substantially smaller than the standard uncertainty on the average observer and were comparable to what are considered just-noticeable-differences in the CIE u'v' chromaticity diagram, supporting the use of memory color based internal references to study chromatic adaptation mechanisms.

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“…Recent experimental evidence is divided, demonstrating heightened colour constancy for colour matches of Munsell papers in real scenes containing (among other fruits) a banana [19] but no effect of an image of a real banana image on colour matches of simulated patches [23]. These experiments address surface colour specifically, and while it is not clear whether colour constancy mechanisms are optimised for frequently encountered or natural surface colours, it is also unclear whether constancy mechanisms are biased towards illuminations to which we are commonly exposed.…”

Section: Introductionmentioning

confidence: 99%

Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

et al. 2014

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The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

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No measured effect of a familiar contextual object on color constancy

Cited by 16 publications

References 39 publications

Uncertainty of sensory signal explains variation of color constancy

Uncertainty of sensory signal explains variation of color constancy

Study of chromatic adaptation using memory color matches, Part I: neutral illuminants

Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

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