共查询到20条相似文献，搜索用时 15 毫秒
1.
María L. F. de Mattiello 《Color research and application》2005,30(6):416-426
The objective of this article is to analyze different color matching functions (CMFs) obtained with three (650, 530, and 460 nm) and four primary colors (650, 565, 513, and 460 nm), using both monoptic and dichoptic central vision. This strategy helps to clarify (i) lack of additivity of brilliance; (ii) shift in maximum sensitivity peaks of CMFs when experimental conditions change; (iii) variations in luminance for the same reason; (iv) strong metamerism of the mixtures; and (v) differences of chromatic opponence between monoptic and dichoptic vision. The results obtained reflect two important facts: marked stability of the visual system, which allows the experimental conditions analyzed to be solved with an equal degree of success, and plasticity based especially on the balance of retinal illumination, which was maintained at an average of 40 trolands. The results obtained bring to mind an assertion made by MacAdam to the effect that the law of additivity when applied to luminance is not applied to measurements of brightness. Perceptively, brightness is not additive, and so CMFs should not be considered as significant functions in computing tristimulus values R, G, and B. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 416–426, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col. 相似文献
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Changjun Li M. Ronnier Luo Bryan Rigg Robert W. G. Hunt 《Color research and application》2002,27(1):49-58
CMCCAT97 is a chromatic adaptation transform included in CIECAM97s, the CIE 1997 colour appearance model, for describing colour appearance under different viewing conditions and is recommended by the Colour Measurement Committee of the Society of Dyers and Colourists for predicting the degree of colour inconstancy of surface colours. Among the many transforms tested, this transform gave the most accurate predictions to a number of experimental data sets. However, the structure of CMCCAT97 is considered complicated and causes problems when applications require the use of its reverse mode. This article describes a simplified version of CMCCAT97— CMCCAT2000—which not only is significantly simpler and eliminates the problems of reversibility, but also gives a more accurate prediction to almost all experimental data sets than does the original transform. © 2002 John Wiley & Sons, Inc. Col Res Appl, 27, 49–58, 2002 相似文献
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CAT02, the most widely used chromatic adaptation transform to characterize the chromatic adaptation mechanism in the human visual system, includes a factor D to characterize the degree of chromatic adaptation. This factor, however, is only determined by the luminance level of the adapting field and surround. This study was designed to investigate how the change of adapting chromaticities and the simultaneous changes of adapting chromaticities and luminance affect the degree of chromatic adaptation and color appearance on computer displays. The human observers adjusted the color appearance of various familiar objects and cubes on different display backgrounds. A higher degree of chromatic adaptation was found when using familiar objects, which was likely due to the cognitive mechanism. Both the adapting chromaticities and luminance significantly affected the degree of chromatic adaptation, with a lower degree under an adapting condition with a lower adapting correlated color temperature and a lower adapting luminance. In addition, the effect of adapting luminance on colorfulness (known as the Hunt Effect) was likely to be overpredicted in CAM02-UCS, which merits further investigations. 相似文献
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Ralph W. Pridmore 《Color research and application》2008,33(1):77-81
In present convention, chromatic induction (simultaneous and successive contrast) is usually held to be an opponent color process. Fifty years ago, it was an accepted complementary color process. The latter was never disputed yet apparently overlooked, and is here shown to be the more accurate account by inspecting afterimages and published data on simultaneous and successive hue induction. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 77–81, 2008 相似文献
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Color difference calculations are usually applied to match or tolerance of small differences between large (>2°) visual fields. In contrast, we examine here the application of ultra‐large color differences to enhance conspicuousness and discriminability of small (1° subtense or smaller) visual targets, e.g., in visual information displays. We show that CIEDE2000, and color difference metrics based on the OSA Uniform Color Space and CIECAM02 are superior to CIELAB and CIELUV. Considering gray scale only, we show that Whittle's JND metric of achromatic contrast is as good as L* for this purpose, while also modeling contrast polarity and “crispening.” Furthermore, using this JND metric, we replicate Highnote's finding that elongation of small targets affects their apparent contrast. We discuss the perceived fading of color differences when targets become smaller, and suggest practical methods to mitigate the adverse effect on color conspicuousness and discriminability. © 2009 Wiley Periodicals, Inc., Col Res Appl, 2010. 相似文献
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Ralph W. Pridmore 《Color research and application》2010,35(6):425-442
A theory of chromatic adaptation is derived from Parts I and II, and presented in terms of relative wavelength, purity, and radiant power, leading directly to a predictive model of corresponding hue, chroma, and lightness. Considering that even simple animals have effective color vision and color constancy, the aim was to develop a simple model of complete adaptation. The model is tested against well‐known data sets for corresponding colors in illuminants D65, D50, and A, and for small and large visual fields, and performs comparably to CIECAM02. Constant hue is predicted from Part I's mechanism of color constancy from invariant wavelength ratios, where constant hues shift wavelength linearly with reciprocal illuminant color temperature. Constant chroma is predicted from constant colorimetric purity. Constant lightness is predicted from chromatic adaptation of spectral sensitivity represented by power ratios of complementary colors (rather than cone responses which lack spectral sharpening). This model is the first of its type and is not formatted for ease of computation. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010 相似文献
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The hue perception and ‘warm‐cool’ feelings were investigated, in response to various lighting settings, following the adaptation to either 3500K or 5000K to compare which one—between conventional iso‐Correlated Color Temperature (CCT) and a new one based on CIE u'v′ color space—is more compatible with the visual perception. Twenty participants evaluated hue and warm‐cool feelings for 48 test lighting settings, by observing an empty gray booth. The results showed that yellow‐blue and ‘warm‐cool’ feelings are closely located around the Planckian locus, while red‐green roughly follows the line orthogonal to the Planckian locus in CIE u'v′ color space, at both 3500 K and 5000 K settings. This suggests that u'v′ color space correlates better with human perception. 相似文献
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Gunilla Derefeldt Tiina Swartling Ulf Berggrund Peter Bodrogi 《Color research and application》2004,29(1):7-19
This report surveys cognitive aspects of color in terms of behavioral, neuropsychological, and neurophysiological data. Color is usually defined as a color stimulus or as perceived color. In this article, a definition of the concept of cognitive color is formulated. To elucidate this concept, those visual tasks are described where it is relevant: in color categorization, color coding, color naming, the Stroop effect, spatial organization of colored visual objects, visual search, and color memory. © 2003 Wiley Periodicals, Inc. Col Res Appl, 29, 7–19, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10209 相似文献
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We performed subjective experiments to evaluate color matching performance of the Spectral Properties Estimation Model (SPEM) and six other models (von Kries, CIELAB, LLAB, RLAB, Nayatani, and CIECAM97s) between two CRT monitors whose whites were quite different. Moreover, we evaluated color matching of these models between a CRT monitor and a printed image set in a dark room. The SPEM we developed is a new chromatic adaptation model based on hypothetical spectral properties estimation. This article describes the subjective experiments and the results obtained. The SPEM produced good color matching performance in the experiments. The detailed algorithm of the SPEM is given in the Appendix. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 445–453, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10197 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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J. A. Díaz L. Jimnez del Barco J. R. Jimnez E. Hita 《Color research and application》2001,26(3):223-233
The present study uses simple reaction time (RT) to examine the temporal response to chromatic changes of the red‐green (L‐2M) and yellow‐blue (S‐(L+M)) chromatic opponent channels. The hue‐substitution method was adopted to negate the luminance channel and generate changes in the chromatic input. The equiluminant stimuli were distributed along three tritanopic and three red‐green confusion lines. RTs were measured at equiluminance from three reference stimuli with chromatic changes occurring in either the tritan or red‐green directions. These reference stimuli also allowed evaluation of the influence of chromatic adaptation level on RT. The results showed that the mean value of RT, for the cone‐input variation either of the L‐2M channel (S‐constant cone axis) or of the S‐(L+M) channel (L&M‐constant cone axis), was described by a similar law as for luminance variations (Piéron's law). Then, the sensitivity of the two channels for chromatic changes was equalized to study their relative response speed. In addition, for both axes, an increase in the chromatic adaptation level lengthens response delay. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 223–233, 2001 相似文献
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We have measured the chromatic‐discrimination ellipses with different luminances for 66 stimuli distributed throughout the CIE‐1931 chromatic diagram. The distribution of these stimuli enabled us to analyze the influence of luminance on discrimination from clearly photopic levels to levels that could enter the mesopic range. The results show a clear influence of the luminance level on the areas of the chromatic‐discrimination ellipses. These areas remain almost constant when the luminance level is clearly photopic, and clearly increase when the luminance diminishes. However, it is not necessary that the luminance level diminish far below 2–3 cd/m2 to detect a substantial increase in the area of the ellipses. According to our data, within the photopic range appears a transition interval of luminance above which the most pronounced increase in the area of the ellipse would be appreciable. Other parameters characteristic of discrimination ellipses, such as orientation and relation to semi‐axes, vary with the luminance level, although without clearly following any rule. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 123–131, 2001 相似文献
15.
William A. Thornton 《Color research and application》2000,25(2):148-150
Suggested optimal “primaries” and concomitant optimal gamut for any form of device or product whose output serves as input to the normal human visual system: TV‐like images, or images reflected from illuminated hardcopy. For those devices and products using additive coloration, three spectral primaries 450–530–610 nm, and their associated gamut, are suggested as goals. For those using subtractive coloration, three reflective components, of width perhaps 50–60 nm at half‐height and peaking at the same wavelengths, are suggested. Thus, in either case, the light from each pixel of the generated color image entering the pupil of the normal human observer is composed of a mixture of that observer's prime colors. “Prime colors” are defined as usual as (a) the wavelengths marking the peaks of the three spectral sensitivities of the (trichromatic) normal human visual system, and, thus, (b) those spectral lights to which the normal human visual system responds most strongly per watt of power content input to the pupil. Spectral sensitivities of the normal human visual system are carefully distinguished from those of the CIE Standard Observers. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 148–150, 2000 相似文献
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Eva M. Valero Juan L. Nieves Javier Hernndez‐Andrs Jos A. García 《Color research and application》2004,29(3):177-182
We have examined the influence of the mean luminance level on the detection thresholds for luminance and red–green chromatic gratings for three different spatial frequencies. The changes in detection thresholds according to the mean luminance level reflect the two different regions, the DeVries–Rose and Weber ranges, found in previous studies. The results for luminance gratings suggest that the transition luminance is proportional to the spatial frequency of the grating. Predictions based on the constant‐flux hypothesis indicate, however, that the transition luminance is proportional to the square of the spatial frequency of the grating and so do not describe the distributions of luminance contrast thresholds adequately. For chromatic gratings, we obtained the same transition luminance for the two lowest spatial frequencies, showing that luminance and chromatic mechanisms behave differently as far as the dependence of the transition luminance on spatial frequency is concerned. Our results suggest that the transition luminance is related to the peak spatial frequency of visual mechanisms that respond to luminance and chromatic gratings. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 177–182, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20003 相似文献
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This research extends the previous RIT-DuPont research on suprathreshold color-difference tolerances in which CIELAB was sampled in a balanced factorial design to quantify global lack of visual uniformity. The current experiments sampled hue, specifically. Three complete hue circles at two lightnesses (L* = 40 and 60) and two chroma levels ( = 20 and 40) plus three of the five CIE recommended colors (red, green, blue) were scaled, visually, for hue discrimination, resulting in 39 color centers. Forty-five observers participated in a forced-choice perceptibility experiment, where the total color difference of 393 sample pairs were compared with a near-neutral anchor-pair stimulus of 1.03 A supplemental experiment was performed by 30 additional observers in order to validate four of the 39 color centers. A total of 34,626 visual observations were made under the recently established CIE recommended reference conditions defined for the CIE94 color-difference equation. The statistical method logit analysis with three-dimensional normit function was used to determine the hue discrimination for each color center. A three-dimensional analysis was required due to precision limitations of a digital printer used to produce the majority of colored samples. There was unwanted variance in lightness and chroma in addition to the required variance in hue. This statistical technique enabled estimates of only hue discrimination. The three-dimensional analysis was validated in the supplemental experiment, where automotive coatings produced with a minimum of unwanted variance yielded the same visual tolerances when analyzed using one-dimensional probit analysis. The results indicated that the hue discrimination suprathresholds of the pooled observers varied with CIELAB hue angle position. The suprathreshold also increased with the chroma position of a given color center, consistent with previous visual results. The results were compared with current color-difference formulas: CMC, BFD, and CIE94. All three formulas had statistically equivalent performance when used to predict the visual data. Given the lack of a hue-angle dependent function embedded in CIE94, it is clear from these results that neither CMC nor BFD adequately predict the visual data. Thus, these and other hue-suprathreshold data can be used to develop a new color-difference formula with superior performance to current equations. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 302–313, 1998 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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The estimation of chromatic diversity of natural images is commonly quantified through the computation of the number of discernible colors and has received much attention because of the different implications it has. However, the relationship between that number and the number of colors that really attracts the attention from an observer is still not clear and has been given little attention. New concepts about salient discernible colors‐the salient chromatic diversity of images‐ and remarkable salient colors‐connected colors in the same salient image area‐are introduced as opposed to the classical number of discernible object colors, which is usually evaluated for the global image without differentiating between probable attended and non‐attended image regions. We have used different well‐known saliency models to locate the salient regions in the scenes and have heuristically studied the extent to which those models preserve the chromatic diversity of natural images. Based on a bottom‐up approach, a reduction of around 40%‐55% in the number of discernible colors were obtained, and not all saliency algorithms preserved a uniform sampling of the original color gamut. Thus, our results suggests that particularly the graph‐based visual saliency model got good low dissimilarity values in comparison with other approaches that put emphasis solely on color as the main low‐level feature. Furthermore, we have introduced a quantification scheme of the average number of remarkable salient colors appearing in the images, and have proved how the heuristic‐based analysis of salient image areas can be used to create segmented images automatically according to their salient chromatic diversity. 相似文献