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1.
Rolf G. Kuehni 《Color research and application》2016,41(5):439-444
The question of how many different colors humans can perceive has been of interest to philosophers, psychologists and color scientists for centuries. In recent years the question of the number of distinguishable object color stimuli has been addressed by color scientists by defining a distinguishable color as a given stimulus surrounded by the contour of stimuli just noticeably different from the central stimulus. For a particular set of conditions the number of distinguishable object color stimuli assessed in this manner has recently been found to be slightly larger than 2 million. In this article an argument is made that the related rules are arbitrary and unnecessarily limiting. Based on logical arguments and experimental just noticeable difference data it is shown that, for the conditions involved, a more realistic if conservative number of distinguishable object color stimuli is ～40 million. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 439–444, 2016 相似文献
2.
《Color research and application》2016,41(5):540-576
In his response to the comments on his article ‘How many colors can we distinguish?’ by Flinkman and Laamanen, Kuehni points out that their suggestion for just noticeable differences to be defined as diameters rather than radii in related unit difference ellipsoids or spheres lacks the conceptual and geometric logic behind JND solids and is not valid. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016 相似文献
3.
Rolf G. Kuehni 《Color research and application》2016,41(5):522-529
M. Brill, in his comments “Maximum number of discriminable colors in a region of uniform color space,” offers a different calculation method from that used by R. G. Kuehni in “How many object colors can we distinguish?,” one based on close‐packing of just noticeable difference spheres. The number per just noticeable difference (JND) sphere is lower than that derived in Kuehni's study. Based on the resulting number of close‐packed JND spheres in the CIECAM02/D65 object color solid and Brill's described multiplier of 5.923 potential stimuli within a JND sphere, the resulting number of distinguishable color stimuli is 9.114 million. © 2016 Wiley Periodicals, Inc. Col Res Appl, 00, 000–000, 2016 相似文献
4.
This is a comment on Prof. Rolf G. Kuehni's article, How Many Object Colors Can We Distinguish? We give a reasoning why the previously calculated estimates for the number of discernible colors are valid, apart from the possible deviations caused by uncertainty of JND and non‐uniformity of color space, without correcting them with a coefficient proposed by Kuehni. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016 相似文献
5.
Michael H. Brill 《Color research and application》2016,41(5):492-512
Continuing a discussion by Kuehni, this note examines the problem of fitting as many as possible colors in a 1‐JND radius sphere such that each pair of colors is separated by at least 1 JND. Kuehni announced nine. A first estimate yields a maximum of 13, but this is too many because colors populating adjacent spheres will be too close to each other. Accordingly, I derive the maximum number, , of discriminable colors per unit volume of color space, and then formally compute from this number packing density a number of colors inside the unit sphere. That estimate, nearly 6, will undoubtedly erode when discrete color points are chosen within the unit sphere. Kuehni's estimate of 9 is too high. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016 相似文献
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7.
With the concept of memory colors being considered to play a crucial role for many imaging and lighting applications, the questions how people assess the color appearance of familiar objects and what kind of fundamental characteristics can be derived from these assessments have extensively been studied in the past. However, all of the previous studies, the authors of this article are aware of, lack in realistic viewing and adaptation conditions. In the attempt of overcoming these deficiencies, a new experiment investigating the impact of long‐term memory on the color appearance ratings of 12 familiar test objects was performed. The pooled observer data were modeled in CIECAM02 color space using bivariate Gaussian functions whose centroids define the corresponding memory color centers for each test object. Comparisons with previous results obtained by Smet et al. revealed no significant differences in the reported memory color centers, but showed distinct deviations in the covariance matrices defining the shape of the fitted distribution functions. It is supposed that this new set of functions will lead to significantly different results when being used for the construction of an updated memory‐based color quality metric. 相似文献
8.
With their inherent ability of serving as an internal reference, memory colors provide a very powerful concept in the evaluation of color rendering properties of white light sources with respect to visual appreciation. Recent results for example suggest fairly good correlations between memory-based color quality metrics and the observers' general color preferences. However, due to technical limitations in the design of the underlying psychophysical experiments, they generally lack the explicit inclusion of realistic viewing and adaptation conditions, which is supposed to have a nonnegligible impact on the model prediction performance. In addition, intercultural effects might play a crucial role in the context of memory colors. For these reasons, the current article investigates the impact of both the adapted white point and the observers' cultural background on memory color assessments in order to contribute to a better understanding of these dependencies and their interactions. For this purpose, the color appearance rating results of Chinese and German observers were collected for a selection of 12 different familiar test objects assessed under two different adaptation conditions at 3200 K and 5600 K, respectively. From the statistical analysis of the experimental data, it is shown, in accordance to previous studies, that the impact of the observed intercultural deviations is likely to be of no practical importance even though significance is found. Despite considerably larger effect sizes, the same must be concluded for the two tested adaptation conditions. 相似文献
9.
Matthias Scheller Lichtenauer Peter Zolliker Iris Sprow 《Color research and application》2013,38(5):334-343
Color technology needs specifications to which extent physical differences of stimuli correspond to differences in perception. Generalized linear models (GLMs) have proved successful to provide such specifications from choice‐based experiments. However, the use of GLMs imposes practical restrictions on the experiment and stimulus parameters. We propose an alternative analytic approach based on machine learning and demonstrate its use in designing and analyzing choice‐based experiments with multiple stimulus dimensions. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 334–343, 2013 相似文献
10.
An elaborated subjective color model is presented that includes the predictions of emulated Benham disk results and additional predictions that refer to local and remote achromatic illuminations on perceived subjective color shifts. A computer emulated Benham disk pattern was used as a stimulus to test the effects of remote illumination on its color sensation. An analytical model and its predictions are proposed in order to account for the results of the perceived hue shift, when changing either the remote illumination area or the stimulus illumination. This model is based on previous retinal color‐coded cells responses which yield the subjective color, and on local and remote adaptation mechanisms. The similarity between the role and mechanism of remote illumination (achromatic or chromatic) in subjective and perceived color is also discussed. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 197–208, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10145 相似文献
11.
Boundary colors are observed when light from a scene is dispersed by a prism or diffraction grating. We discovered that patterns with repeating black and white stripes can produce repeating bands of boundary colors with two hues. These hues are virtually constant as measured by chromaticity or CIELAB. We found seven cases of this kind using a new appearance model for boundary colors. The model correctly predicts that green and magenta bands recur as stripe widths and dispersion strength vary. The first green/magenta case in the sequence traces out an accurate ellipse in XYZ color space. Green and magenta bands are prominent in supernumerary rainbows and interference rings, and we explain why that might be the case. The explanation is based on an interesting property of the visible spectrum. In addition to the green/magenta cases, the other cases are orange/cyan, yellowish‐green/purple, and yellow/violet. The success of the boundary color appearance model implies that bands are perceived as if the wavelength responses of the cones were essentially independent, which contradicts the actual behavior of cones. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 135–146, 2015 相似文献
12.
I. Tortajada Montañana J. Montalvá Colomer M. Aguilar Rico 《Color research and application》2012,37(5):336-342
The aim of this article is to study the influence of an achromatic Ronchi grating (white and black stripes) used as a background, over a periodic chromatic test (red or green). Depending on the grating frequency, two parameters were used to study this influence: modulation ratio and grating contrast. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012 相似文献
13.
Despite the crucial role of color appearance in forming first impressions, it is still not clear how color evokes personality associations—that is, a color‐personality association (CPA). This study aims to propose a method for quantifying the relationships between color attributes and CPAs for single colors. Specifically, we first collected the CPAs of five traits evoked by single colors (i.e., extraverted–introverted, moody–unemotional, agreeable–disagreeable, organized–disorganized, and wide interests–narrow interests) in a carefully controlled experiment. Then, multiple linear regression (MLR) analyses were adopted to predict these CPAs based on three color attributes (lightness, chroma, and hue). Our results showed that (1) the personality associations could be evoked by colors and perceived consistently by observers; (2) the relationships between the color attributes and the CPAs could be well quantified by separately conducting MLR analyses in different regions of hue (i.e., red, green, blue, and yellow regions); and (3) both lightness and chroma were significant predictors in almost all predictive models and they might have different relative importance or directions of effect when predicting the CPAs in different regions of hue, even for the same trait. This study improves the understanding of how color evokes personality associations and takes the first step toward developing the method for predicting the CPAs for multicolor combinations. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 388–396, 2017 相似文献
14.
Two color-memory experiments were performed to investigate whether observers tended to confuse colors with a smaller color difference in memory or colors in a same color-category region. We made color stimuli on a color CRT. Color difference was determined by a simultaneous color discrimination experiment. Color-category regions were obtained by a categorical color-naming experiment using the 11 basic color names: white, black, red, green, yellow, blue, brown, orange, purple, pink, and gray. The results show that two colors with a certain color difference can be confused more easily when they are in a same color category than in different color categories, and that colors identified with memory tend to distribute within their own color-category regions or their neighbor color-category regions, depending on their positions in a color space. These findings indicate that color memory is characterized by the color categories, suggesting a color-category mechanism in a higher level of color vision. © 1996 John Wiley & Sons, Inc. 相似文献
15.
Ralph W. Pridmore 《Color research and application》2011,36(6):394-412
I describe complementary colors' physiology and functional roles in color vision, in a three‐stage theory (receptor, opponent color, and complementary color stages). 40 specific roles include the complementary structuring of: S and L cones, opponent single cells, cardinal directions, hue cycle structure, hue constancy, trichromatic color mixture, additive/subtractive primaries, two unique hues, color mixture space, uniform hue difference, lightness‐, saturation‐, and wavelength/hue‐discrimination, spectral sensitivity, chromatic adaptation, metamerism, chromatic induction, Helson‐Judd effect, colored shadows, color rendering, warm‐cool colors, brilliance, color harmony, Aristotle's flight of colors, white‐black responsivity, Helmholtz‐Kohlrausch effect, rainbows/halos/glories, dichromatism, spectral‐sharpening, and trimodality of functions (RGB peaks, CMY troughs whose complementarism adapts functions to illuminant). The 40 specific roles fall into 3 general roles: color mixture, color constancy, and color perception. Complementarism evidently structures much of the visual process. Its physiology is evident in complementarism of cones, and opponent single cells in retina, LGN, and cortex. Genetics show our first cones were S and L, which are complementary in daylight D65, giving a standard white to aid chromatic adaptation. M cone later split from L to oppose the nonspectral (red and purple) hues mixed from S+L. Response curves and wavelength peaks of cones L, S, and (S+L), M, closely resemble, and lead to, those of opponent‐color chromatic responses y, b, and r, g, a bimodal system whose summation gives spectral‐sharpened trimodal complementarism (RGB peaks, CMY troughs). Spectral sharpening demands a post‐receptoral, post‐opponent‐colors location, hence a third stage. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011 相似文献
16.
Rolf G. Kuehni 《Color research and application》2007,32(2):92-99
The development of the idea of simple or fundamental colors in Western culture from classical Greece to the early 17th century is shown, with particular emphasis on writers in the 16th and early 17th centuries. Four streams of thought are found: (1) Aristotle's seven colors, congruent with seven tastes and seven tones, thus symptomatic of an underlying general harmony; (2) Four‐basic‐color sequences where colors are emblematic of the four classical elements; (3) Spectral sequences; (4) Three simple chromatic colors between white and black, based on colorant mixture. In the late 16th century seven‐color sequences came to represent categorical sequences, in addition to shorter fundamental color sequences. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 92 – 99, 2007 相似文献
17.
Ralph W. Pridmore 《Color research and application》2008,33(3):238-249
The wavelengths of several constant hues over four illuminants (D95, D65, D50, A) are derived from several sets of published data. In the plane of wavelength and reciprocal illuminant color temperature (MK?1), the wavelengths of constant hues plot straight approximately parallel lines whose mean slope is about 87°. Parallel lines give invariant wavelength ratios, hence constant hues in this plane are near‐invariant wavelength ratios across illuminants. As recently demonstrated, the complementary wavelengths to a constant hue (across illuminants) represent the complementary constant hue; these complementary wavelengths also plot a near‐parallel line to the first constant hue. To confirm and further define the constant slope of these lines, it is shown that complementary wavelength pairs, per CIE data, can only plot parallel straight lines at the angle of 87° ± 1. In summary, near‐parallel sloping lines represent constant hues at near‐invariant wavelength ratios. This mechanism of color constancy is shown to relate to the well‐known theory of relational color constancy from invariant cone‐excitation ratios. In the visual process, the latter ratios are presumably the source of the former (invariant wavelength ratios). © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 238–249, 2008 相似文献
18.
Y. Nayatani 《Color research and application》2001,26(4):290-304
Some modifications are made to the achromatic color perceptions in Hering's opponent‐colors theory. They are the introduction of the reference color Gray and the use of the orthogonal coordinate system. The modified opponent‐colors theory has a symmetrical structure for the three opponent‐colors axes, whiteness‐grayness‐blackness, redness‐grayness‐greenness, and yellowness‐grayness‐blueness, and it unifies the Hunt and the Stevens and Jameson–Hurvich effects. It is also noted that two kinds of color‐appearance spaces exist. One is the color‐appearance space derived from color perceptions of object colors (called the CPS color‐appearance space). The other is that modeled from their colorimetric values for predicting color perceptions (called the UCS color‐appearance space). The CPS color‐appearance space is mainly described in this article. Scaling of the CPS color‐appearance space and the existence of the reference color perception Gray are discussed in detail. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 290–304, 2001 相似文献
19.
Ralph W. Pridmore 《Color research and application》2016,41(5):468-476
In a recent article on color constancy, the chromatic adaptation model was of a novel type comprising three components separately calculated—hue, chromaticness, and lightness. The constant hue component was a simple calculation of predicted wavelength but the other two components were less direct. This article provides an algorithm to simplify the model's calculation. Calculation is far simpler and more intuitive than conventional models using complex 3 × 3 matrix transforms with their various and contentious adaptation primaries and potential disadvantages (e.g., in brightness and color gamut). The model is shown to be at least as accurate as six other (conventional) models and does not require high math skill. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 468–476, 2016 相似文献
20.
探讨牙科陶瓷配色的方法和机理，通过将钒锆黄、锆镨黄、锆铁红、铬铝锌红对牙科陶瓷进行配色。采用分光光度计测量了样品的L＊、a＊、b＊值和色差，并与VitaA2和ceramcoA2瓷粉对比，研究了样品色差与配方之间的关系。 相似文献