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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
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《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
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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
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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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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
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Shih‐Wen Hsiao Ming‐Feng Wang Dai‐Jung Lee Chien‐Wei Chen 《Color research and application》2015,40(4):341-351
In the recent years, great importance has been shown toward the cultural creativity in Taiwan. Cultural identification and determining how best to apply it to commercial products require investigating and compiling a vast amount of cultural information, along with the individual ideas of designers, to develop new cultural products. During the product development and design process, the color scheme is the final and most important element. It not only represents the first image of the product but also elicits the important first‐sight impression of consumers. Consequently, color ranks first in cultural commodity development. By understanding the Taiwanese culture, as well as assessing, verifying, and internalizing it into the materials that can be used by the designers, this study uses an artificial neural network system and simplifies the collected pictures that are representative of the Taiwanese culture into groups of different matching colors to assist designers in developing cultural commodities with different features and according to different cultural styles. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 341–351, 2015 相似文献
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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
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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
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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
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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
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Within the framework of this article the results of two experiments are compared, on the preference and harmony content of neutral colours, carried out 50‐year apart, in 1967 and 2017. The experimental conditions and sample boards, shown to the experimental subjects were identical in both occasions. Result shows that in 2017 the very light and very dark colours have been preferred over other colours, against the findings in1967. At the same time, the experimental subjects found the colour pairs, formed of colours with higher contrast, more harmonic in 2017 than 50‐year earlier in 1967. 相似文献
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We have performed a computational color analysis of images of paintings for six master painters: Titian, Rubens, El Greco, Velázquez, Rembrandt, and Vermeer. These painters show the evolution from the renaissance to the baroque style. Different first and second‐order statistical parameters have been obtained and analyzed in order to fix which of them can be common for the different artists and which of them can be representative of a certain period of time or the evolution of the art. The firsts include the orientation and semi‐axes ratio of the ellipses that define the gamut in the chromaticity diagram and the dependencies with the frequency of the power of the Fourier transforms. Most differences among artists can be found in the volume and area of the gamut, the number of discernible colors which is greater for Titian, El Greco and Rubens, compared to Velázquez, Rembrandt and Vermeer, the average value of L* and the number of dark pixels. 相似文献
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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
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This study investigates how a holistic color interval, i.e., the nondirectional color difference between a pair of colors in a CIELAB uniform color space, influences perceived color harmony. A set of 1035 test color pairs displayed on a CRT was evaluated for the degree of harmony. These test color pairs consist of pairs combined from among the selected 46 test colors evenly distributed in color space. The subjects were asked to select their three preferred colors from these 46 test colors and then to evaluate the degree of harmony of the test color combinations. The color intervals (ΔE) of each test color combination were calculated and treated as values of an independent variable. In addition, the evaluated degrees of color harmony were considered as values of a dependent variable, in which statistical analysis confirmed the relationship: the degree of harmony is a cubic function of the color interval. Moreover, the plot of this relationship allowed us to identify four color intervals: roughly corresponding to the regions of first ambiguity, similarity, second ambiguity, and contrast in Moon and Spencer's model. However, our results indicated that Moon and Spencer's principles for classifying harmonious/disharmonious regions in terms of the color interval for three color attributes—lightness, chroma and hue—may be inappropriate in predicting perceived color harmony. As for the color intervals between a pair of colors considered as a function of the three attributes, the interval for lightness may have a predominant effect on color harmony, expressed in terms of a cubic relationship. Results of the study further demonstrated that the subject's choice of colors significantly influences perceived color harmony. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 29–39, 2001 相似文献
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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
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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
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描述和评论了敦煌莫高窟壁画的色标及变色问题,并从涂料专业的角度对敦煌莫高窟壁画的保护和维修问题提出了看法。 相似文献