共查询到20条相似文献，搜索用时 15 毫秒
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J. A. Martínez F. J. Vega J. A. Díaz F. Prez‐Ocn J. R. Jimnez 《Color research and application》2005,30(5):363-370
Recently,in our laboratories, a set of color‐matching functions (cmfs) has been formulated for small fields by using two groups of real observers: JAM, MM, CF and AY, JR, MR, JL, JA, FP. The measurements of these cmfs have been made using different experimental devices and methods and it has enabled us to propose a New Deviate Observer for small fields (JF‐DO). This new JF‐DO was derived from the average observer of our nine real observers, following the technique used by the CIE to establish the Standard Deviate Observer (CIE‐1989 SDO), which was established for fields of 10°, despite the CIE's assumption that it can be applied to smaller fields. In the present work, we report experimental results of the JF‐DO using metameric reflectances in comparison to the CIE‐1931 Standard Observer and to the CIE‐1989 SDO. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 363–370, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col. 相似文献
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Color‐matching functions (CMFs) were derived with the Maxwell method for 10 subjects using two field conditions: (1) horizontally bisected circular 10° and (2) vertically bisected rectangular 102° (wide) × 50° (high). The primary set was composed of 453–533–601 nm components with a mean full‐width at half maximum of 18.3 nm; the reference field was illuminated with daylight fluorescent lamplight. Field size had a significant effect on the shape of the resulting CMFs. Under the large‐field conditions subjects were less sensitive to shorter wavelengths as characterized with the b? function and had higher sensitivities to the longer wavelengths as characterized with the r? function. © 2005 Wiley Periodicals, Inc. Col Res Appl, 31, 18–29, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20170 相似文献
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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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The UNL trichromatic colorimeter was designed to perform color‐matching experiments under a range of stimulus conditions. The colorimeter can be set up with a conventional 10° structure‐free bipartite viewing field (either horizontally or vertically bisected) but can also be configured for field sizes as large as 102° (wide) × 50° (high), and depth cues can be introduced into the viewing field. This article documents the construction and performance of the apparatus, including the structural components, light sources, optics, filters, and instrumentation. Maxwell method CMFs measured at a homogeneous 10° horizontally bisected field are reported with results that compare favorably with CMFs reported by Thornton under similar stimulus conditions. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 209–220, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20109 相似文献
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J. A. Martínez F. Prez‐Ocn A. García‐Beltrn E. Hita 《Color research and application》2003,28(3):209-215
The CIE established the Standard Deviate Observer (SDO) CIE 1989 for fields of 10°, enabling the evaluation of discrepancies caused by the variability among these observers. This observer could also be applied to smaller fields, depending on the physiological causes of this variability in color‐matching functions (cmf's) among observers. Here, we have obtained a new Deviate Observer (which we call JF‐DO) established from the cmf's for small fields (2°) corresponding to two groups of real observers: JAM, MM and CF; AY, JR, MR, JL, JA and FA. Both groups of cmf's were measured experimentally in our laboratories using one for each of the different experimental methods and devices. All the new cmf's of the 9 real observers were referred to a new, unique system of unreal primaries, which we call X′Y′Z′ (derived in a way similar to that of the CIE 1931 XYZ system of unreal primaries). To establish a new JF‐DO for small fields, we followed a procedure similar to the one used by the CIE to establish the CIE 1989 SDO. A comparative study was also made between the cmf's of the CIE 1989 SDO (established for fields of 10°), the SDO from Stiles‐Burch (which we call Poza‐SDO, developed for small fields), and our JF‐DO. For this comparison, the cmf's of all these deviate observers were referred to the new system of unreal primaries X′Y′Z′. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 209–215, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10146 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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Four data sets are analyzed to quantify three effects of luminance of samples on chromaticity discrimination: on ellipse area, axis dimensions (a and b), and a/b ratio. Ellipses for aperture, surface, and simulated surface colors in CIE 1931 and 1964 x, y, Y color spaces are shown to reduce axis dimensions with higher luminance by different functions for the major and minor axes. Reduction is greater for major than minor axes, thus improving ellipse circularity. The functions plot straight lines in log‐log scale as power law equations, except luminances below 3 cd/m2. We give formulae to predict a and b axes, a/b ratio, and ellipse area for almost any luminance in x, y, Y spaces. Effect of luminance is remarkable on ellipse area, which on average halves with every 3.5 times higher luminance. To illustrate the substantial effects of luminance, RIT‐DuPont ellipses are predicted for three levels of equal luminance at 42, 212, and 2120 cd/m2. In the latter, ellipses are much smaller and are nearer circular than in the former. Higher luminance is known to improve color discrimination, so reduced ellipse area is to be expected but does not occur in CIELAB and DIN99 spaces because of lack of luminance‐level dependency. We discuss our results' implications on uniform color space. Weber fraction ΔY/Y indicates brightness discrimination decreases with increasing luminance and is thus independent of chromaticity discrimination. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 186–197, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20107 相似文献
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Over time, much work has been carried out to ascertain the validity of Grassmann's laws, Abney's law, CIE standard color‐matching functions and, up to now, no definitive answer has been given. Some of the phenomena subject of this debate are considered. An apparatus for color matching in 1.8° visual field has been realized with two sets of primary lights with broad spectral bands. This kind of primaries is the great difference with respect to other laboratories because it allows an indirect check of the Grassmann additivity law on the basis of the spectra and individual color‐matching functions by evaluating: (1) the tristimulus values of the primary lights; (2) the transformation matrices between the two reference frames defined by the two primary sets; and (3) the tristimulus values associated to all the pairs of matching lights in the bipartite field produced in the evaluation of the two sets of color‐matching function. The discrepancies of the data resulting in the check (1) and (2) are all compatible with the range defined by the uncertainty propagation of the individual color‐matching functions. In the check (3) fifteen tristimulus values over 18 have a discrepancy lower than one standard uncertainty. Grassmann's proportionality law is checked directly by reducing the matching lights with a neutral filter and holds true. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 271–281, 2008. 相似文献
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Color‐matchingfunctions may be considered dimension reduction functions that project a spectral reflectance function into the desired space of colors. Using a gray metameric pair with maximal spectral difference we compare the abilities of various human and other observers with regard to the transition wavelengths for that metameric pair. Transition wavelengths are shown to be a convenient tool for comparing and classifying observers regardless of the number of dimension reduction functions. Four human observers were identified as differing in a comparable manner from the CIE 2° standard observer. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 183–186, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20004 相似文献
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A systematic method of analyzing the colorimetric behavior of a set of observers is proposed. The differences between each observer and a standard one are analyzed with different procedures in two color‐representation systems. It is apparent that these differences strongly depend on the color‐representation system in which they are analyzed. Results obtained in this work indicate that comparison between two observers should be carried out by applying an optimized operator. This operator minimizes the differences between the color‐representation systems associated with the observers that are compared. The proposed method should be applied when color‐matching properties of a set of observers, or when color matching obtained with different colorimetric instruments, are compared. © 2002 Wiley Periodicals, Inc. Col Res Appl, 28, 15–24, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col. 相似文献
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Accurate colorimetry starts with accurate color matching functions (CMFs). Due to changes in the macular pigment and cone pigment optical densities at different retinal locations, different CMFs are required for different stimulus field sizes. To characterize the accuracy of the CIE recommendation for the use of 2° and 10° standard CMFs and the field-size dependent CIEPO06 model, in this study, a series of achromatic matching experiments were performed with 2°, 4°, 6°, 8°, and 10° bipartite fields using spectrally narrowband primaries. Using the CIEPO06 model, optimal field sizes were estimated that minimize the chromaticity differences between the spectrally narrowband observer matches and the spectrally broadband achromatic target. It was found that the optimal field size estimated using the CIEPO06 model is close to half the actual bipartite field size in most cases, except for the 2° field. The discrepancy between the 10° bipartite field in Stiles & Burch's experiments and our optimal field size (6.54°) was assumed to be due to different individual color comparison strategies. However, the results of experiments requiring specific observer gaze positions did not support this assumption and the reason for the discrepancy remains unclear. Confirming our earlier results, the primary set (636, 521, 447 nm) was again found to be largely insensitive to changes in CMFs and to provide the most accurate matches under various fields of view. The inter- and intra-observer variability ellipses for 2° matches are larger than those for 10°, consistent with Brown's finding for color discrimination ellipses. The magnitude of the intraobserver variability was similar for all field sizes, except for 2° field size, where matching errors were larger for some primary sets. 相似文献
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Yuetong Shen;Min Huang;Xinyuan Gao;Minchen Wei;Xuping Gong;Dan Wang; 《Color research and application》2024,49(6):600-608
The performance of color matching functions (CMFs) is important to color specification and calibration. In comparison to the great number of studies focusing on the effect of primary set, few studies focused on how observer age and field of view (FOV) jointly affected the performance of CMFs. In this study, a color matching experiment with three different primary sets, which were carefully selected based on our previous study, was carried out by two observer age groups under four FOVs (i.e., 2°, 4°, 8°, and 13°). The results suggested that the observer age had a more significant effect than the FOV, and the change of the FOV did not introduce a systematic trend to the color matching results. Neither the CIE 1931 2° nor 1964 10° CMFs were found to accurately characterize the color matches. The CIE 2006 CMFs with the FOV set to the experiment setup also did not have good performance. On average, the CIE 2006 2° CMFs were found to have the best performance, without considering the effects of the observer age and FOV. 相似文献
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Fernando Carreño José Miguel Ezquerro Jesús M. Zoido 《Color research and application》2009,34(3):194-200
An analytical method to determine how color‐matching functions influence the perception of chromaticity differences is proposed. We show that, as a consequence of the observer metamerism, a metameric color‐match perceived by one observer may appear to be a significant mismatch to a different observer. It is also shown that, on average, the differences between the color‐matchings made by two different observers can be estimated to be in the order of 2 CIELAB units. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 194–200, 2009 相似文献
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Fernando Carreo Jos Miguel Ezquerro Jesús M. Zoido 《Color research and application》2006,31(6):468-474
We present an analytical method to analyze, from a theoretical point of view, the influence of color‐matching functions on the perception of luminance thresholds. We show that the thresholds depend on the spectral responsivities of each observer. We also analyze the influence of luminance level on the thresholds: a strong inter‐observer variability is found at low or moderate luminance levels (0.02 < Y < 1 ft?L) whereas at high intensities (1 < Y < 7 ft?L) the thresholds are observer‐independent. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 468–474, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20259 相似文献
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Cara Cocking Stephan Helling Marcus Oswald Peter Rammelsberg Gerhard Reinelt Alexander J. Hassel 《Color research and application》2010,35(3):233-239
A key criterion in the design of dental shade guides used for matching tooth color is that the shade tabs cover the natural tooth color space as completely as possible with a manageable number of tabs. Earlier studies have designed hypothetical shade guides from a given population of tooth colors described in the CIELAB system using the goal of minimizing the mean coverage error. In this study, we investigate this topic using the goal of maximizing coverage, meaning that as many measured colors as possible were within a given color difference from the nearest shade tab of the guide. We use techniques of linear discrete optimization to determine the positions of the shade tabs and consider both color difference formulas, CIELAB and CIEDE2000, in an exemplary tooth color population. We obtain coverage error and coverage figures for hypothetical shade guides of various numbers of tabs designed with the goal of either minimizing coverage error or maximizing coverage. Results show that discrete optimization and the goal of maximizing coverage could be used to improve shade guide development. The described technique could be used not only for dental shade guides development, but also for any purpose requiring coverage of as many colors as possible while keeping the number of reference colors manageable. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010 相似文献