共查询到20条相似文献，搜索用时 15 毫秒
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Arthur D. Broadbent 《Color research and application》2004,29(4):267-272
This article describes the development of the CIE1931 chromaticity coordinates and color‐matching functions starting from the initial experimental data of W. D. Wright and J. Guild. Sufficient information is given to allow the reader to reproduce and verify the results obtained at each stage of the calculations and to analyze critically the procedures used. Unfortunately, some of the information required for the coordinate transformations was never published and the appended tables provide likely versions of that missing data. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 267–272, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20020 相似文献
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The use of colorimetry within industry has grown extensively in the last few decades. Central to many of today's instruments is the CIE system, established in 1931. Many have questioned the validity of the assumptions made by Wright1 and Guild,2 some suggesting that the 1931 color‐matching functions are not the best representation of the human visual system's cone responses. A computational analysis was performed using metameric data to evaluate the CIE 1931 color‐matching functions as compared to with other responsivity functions. The underlying assumption was that an optimal set of responsivity functions would yield minimal color‐difference error between pairs of visually matched metamers. The difference of average color differences found in the six chosen sets of responsivity functions was small. The CIE 1931 2° color‐matching functions on average yielded the largest color difference, 4.56 ΔE. The best performance came from the CIE 1964 10° color‐matching functions, which yielded an average color difference of 4.02 ΔE. An optimization was then performed to derive a new set of color‐matching functions that were visually matched using metameric pairs of spectral data. If all pairs were to be optimized to globally minimize the average color difference, it is expected that this would produce an optimal set of responsivity functions. The optimum solution was to use a weighted combination of each set of responsivity functions. The optimized set, called the Shaw and Fairchild responsivity functions, was able to reduce the average color difference to 3.92 ΔE. In the final part of this study a computer‐based simulation of the color differences between the sets of responsivity functions was built. This simulation allowed a user to load a spectral radiance or a spectral reflectance data file and display the tristimulus match predicted by each of the seven sets of responsivity functions. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 316–329, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10077 相似文献
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A CIELAB anomaly, in which smaller spectrophotometric errors at all wavelengths lead to larger CIELAB differences, is identified. It is shown that the reversal can occur throughout tristimulus space and is colorimetrically important during calibration procedures. Three numerical examples of the reversal, using data from the BCRA tiles, are given. The reversal cannot be attributed entirely to metamerism, which itself may cause large spectrophotometric error leading to small CIELAB difference. The effect is compounded by the nonlinearity of CIELAB relative to tristimulus coordinates. A recommendation for avoiding the reversal is offered. © 2004 Wiley Periodicals, Inc. Col Res Appl, 30, 66–68, 2005; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/col.20076 相似文献
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Julio M. del Hoyo‐Melndez Berta Carrin‐Ruiz Gabriel Riutort‐Mayol Jos L. Lerma 《Color research and application》2019,44(4):547-555
The documentation of archeological sites requires the adoption of non‐destructive techniques to safeguard the unique legacy coming from prehistoric periods. This article tackles the assessment of lightfastness properties on a rock art site to determine the behavior of motif's color deterioration over time in Remígia Cave, Castellón (Spain), which is considered part of a UNESCO World Heritage Site. The measurements were performed using a microfade testing device to analyze the spectral characteristics and the aging properties of the colorant system and various substrates on site. Two scenarios have been identified depending on whether the lightness (L*) parameter of the rocky substrate changes or not in relation with the painted motifs. If the substrate remains stable without any change, red motifs containing iron oxide pigments will become more visible. If the substrate becomes lighter, the pigments will experience similar changes. Therefore, the contrast between paintings and support will be considerably enhanced. 相似文献
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光声光谱技术在色分析研究中的应用 总被引：1，自引：0，他引：1
现行测色法多以常规光谱为基础。通过测量样品对光的透射或反射率以及光源的能量分布,叠合色匹配函数,来寻找颜色的三刺激量,由此获取样品的色别、色饱和度和明度的信息。这些方法的共同特点是定向输入光子,并计量定向输出光子的情况。为了能将测定范围扩展到那些高反射、散射、漫射、辐射和层状样品,对一般常规光谱法是困难的。我们因此提出了光声测色法(PAC)。 相似文献
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James A. Worthey 《Color research and application》2012,37(6):410-423
A companion article introduced a set of orthonormal opponent color matching functions (CMFs). That “orthonormal basis” is an expedient for plotting lights in Cohen's logical color space. Indeed, graphing the new CMFs together (as a parametric plot) gives Cohen's invariant locus of unit monochromats (LUM). In this article, the functions and related vector methods are applied to fundamental problems. In signal transmission and propagation‐of‐errors work, it is desirable to describe stimuli by decorrelated components. The orthonormal CMFs inherently do this, and an example is worked out using a large set of color chips. Starting with the orthonormal functions, related functions, such as cone sensitivities, are graphed as directions in color space, showing their intrinsic relationships. Building on work of Tominaga et al., vectorial plots are related to the problem of guessing the illuminant, a step toward a constancy method. The issue of color rendering is clarified when the vectorial compositions of test and reference lights are graphed. A single graph shows the constraint that the total vectors are the same, but also shows the differences in colorimetric terms. Since the LUM summarizes a trichromatic system by a three‐dimensional graph, dichromatic observers can be represented by 2‐D graphs, revealing details in a consistent way. The “fit first method” compares camera with human, applying the Maxwell‐Ives criterion in graphical detail. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011. 相似文献
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Rolf G. Kuehni 《Color research and application》2001,26(2):141-150
In a systematic optimization process five sets of recent color difference data have been analyzed for commonalities. Adjustment of the X tristimulus values and application of a systematic, surround dependent SL function was found to be beneficial in all cases. Other modifications of the CIE94 color‐difference formula were found to bring improvements only in some cases and may be spurious. Application of what seem to be nonsystematic scale factors in a range of 0.78–1.38 improve correlation between calculated and visual color differences in all cases. After optimization, calculated color difference values explain between 80–90% of the variation in visual color differences. Some of the datasets are shown not to be well suited for formula optimization. Optimization in all cases by set, for three sets of data by quadrant in the a*b* diagram, and for one set by subset did not reveal any additional systematic trends for improvement. It appears that the basic structure of CIE94, with the recommended modifications, is a good approximation as a model for color‐difference evaluation in the range from 0.5–10 units of difference. The model is surround dependent. A number of issues remain to be resolved. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 141–150, 2001 相似文献
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M. Melgosa 《Color research and application》2006,31(3):239-241
This communication reports additional analyses of the dataset presented in the article “A preliminary comparison of CIE color differences to textile color acceptability using average observers” by Mangine, Jakes, and Noel © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 239–241, 2006 相似文献
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James A. Worthey 《Color research and application》2012,37(6):394-409
A set of orthonormal color matching functions is developed, in which the first is an all‐positive achromatic function, the second is red–green, and the third can be loosely described as blue–yellow. The achromatic function, proportional to the familiar $ bar y $ , is a sum of red and green cones. The red–green function uses the same cone sensitivities, but subtracted, with coefficients so that it is orthogonal to the achromatic one. The third function involves all three cones, but is primarily a blue sensitivity. Using this basis to compute the tristimulus vectors of narrow‐band lights at unit power gives Jozef Cohen's locus of unit monochromats, (LUM) an invariant shape now graphed in a space where the axes have intuitive meaning. The extreme points of the LUM reveal the wavelengths that act most strongly in mixtures, a close approximation to William Thornton's Prime Colors. In effect, decades of research converge in three functions and a vectorial schema, demystifying such issues as color rendering and the selection of additive primaries. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011. 相似文献
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Sonja Haastrup Donghong Yu Thomas Broch Kim Lambertsen Larsen 《Color research and application》2016,41(5):484-492
The properties of polypropylene (PP) mixed with masterbatch (MB) and liquid color concentrates (LCC), respectively, were compared by preparing samples of PP with MB and PP with LCC and neat PP as a reference material using 1–4 extrusion cycles. Two colors were examined, i.e., a white color consisting of pigment white 6, and a green color consisting of pigment white 6, pigment blue 15:3, and pigment green 7. The color difference between PP prepared with MB and LCC was determined and the mechanical, rheological, and crystalline properties of PP prepared with MB and LCC were found to be generic. The color of PP obtained from MB and LCC were comparable. Further, it was found that the tensile strength, the viscosity, and the crystal structure obtained were similar when using LCC instead of MB. The viscosity of the treated PP generally decreased with increasing extruder retention time due to thermal degradation. The tensile strength and the crystal structure were independent of increased extruder retention time. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 484–492, 2016 相似文献
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In this research we compare the colorimetric behavior of several observers. For color centers recommended by CIE we have produced large sets of spectral distributions, which are metameric for the CIE 1931 standard observer. For each one of the color centers, we compare the clouds of chromaticity coordinates with the chromaticity thresholds. We define a parameter that provides a quantitative measure of the interobserver variability. This parameter is used to arrange the observers by their degree of likeness. A similar procedure has been used to compare two real observers. It is shown how there is no reciprocity between the colorimetric behavior of two real observers. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 262–269, 2001 相似文献
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In this article, we report new color discrimination ellipsoids calculated from two normal observers, using a CRT device and five values of luminance at each of the five centers recommended by the CIE in 1978 (Col Res Appl 1978;3:149–151). Our main goal was to test the weighting function for lightness adopted by the CIE94 color‐difference model (CIE Publication 116, 1995). Although some of the experimental conditions employed here (CRT monitor, small size of the visual field, and controlled exposure time) did not fit those recommended by this model, our results support the weighting function for lightness proposed by CIE94. The only robust trends observed in the ellipsoids obtained were a confirmation of Weber's law and a decrease in the area of the x, y chromaticity ellipses, when the luminance of each reference stimulus increased towards the one of the surround. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 38–44, 1999 相似文献
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Joni Orava Timo Jääskeläinen Jussi Parkkinen Veli‐Pekka Leppanen 《Color research and application》2007,32(5):409-413
A novel diffractive CIE 1931 chromaticity diagram is generated by utilizing surface relief gratings on a plastic sample. A properly illuminated sample is shown to reflect the CIE chromaticity diagram with exact colors and large gamut. Additive color mixing is accomplished by utilizing the four main peaks of a 4000 K fluorescent lamp's spectrum as the primary colors. The primary grating units are reflecting the combination of the primary colors to the desired viewing angle and thereby forming the correct chromaticity (x, y) at each pixel of chromaticity diagram. Weights of primary colors at each pixel of the diagram are controlled by fixing the relative areas of the primary gratings. The master grating is fabricated with aid of electron beam lithography. The final grating is hot embossed on a polycarbonate sample using an electroplated nickel shim. Chromaticity values are measured from the plastic sample by a spectroradiometer. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 409–413, 2007 相似文献
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Roy S. Berns 《Color research and application》1996,21(6):459-472
Equations such as CIE94 and CMC are now in common use to set instrumental tolerances for industrial color control. A visual experiment was performed to generate a data set to be used in evaluating typical industrial practices. Twenty-two observers performed a pass-fail color tolerance experiment for a single high-chroma yellow color. Thirty-two glossy samples varying in all three CIE-LAB dimensions were compared with a single standard. A near-neutral anchor pair was used to define the quality of match criterion. The pooled pass data were used to fit a 95% confidence ellipsoid. The chromaticness dimension was well estimated by either CMC or CIE94. The lightness dimension was poorly estimated by either equation. Evaluating the sampling distribution of the 32 test samples via a covariance matrix revealed a poor sampling, particularly in the ΔL*Δb* plane. This sampling may have biased the visual experiment. The visual data were used to optimize various color-difference equations based on CIE94 and CMC, where the l:c and total color difference were adjustable parameters. Several methods of optimization are described including minimizing the number of instrumental wrong decisions and logistic multiple-linear regression. Some methods require only pass response data, while others require both pass and fail data. Because industrial tolerances are usually based on a single observer, ellipsoids were fitted for three observers to demonstrate the large variability between observers in judging color differences. It was concluded that when tolerances need to be set based on a single observer's visual responses of samples not well distributed about the standard, typical industrial occurences, one should only adjust the tolerance magnitude based on a statistically valid equation such as CIE94. One should not change l:c or derive a new ellipsoid. © 1996 John Wiley & Sons, Inc. 相似文献
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The purpose of this study is to evaluate the factors affecting the assessment of granite color, such as grain size and texture, and to propose a methodology for this task which would reduce the margin of error associated with this procedure. For this purpose, an evaluation was carried out on the color of several granites with different textures used in the dimensional stone industry to highlight the importance of the sample area, the number of measurements per sample and the aperture of the equipment. A colorimeter was used to measure the granite color according to the CIE‐L*a*b* and CIE‐L*C*abhab systems, in both large slabs and small samples selected in a processing plant of ornamental granites. Granite color characteristics from large slabs had to be obtained with at least 60 shots due to the variation between different slabs. Therefore, several samples are needed for granite characterization. The color of gray granites does not vary significantly. Nevertheless, the more weathered granites show significant differences which are more evident in the b*‐parameter, or the yellow–blue component, which allow the use of the colorimeter for quality control. By doing so significant differences among the rock pieces used in a single building can be avoided. There were no significant differences found in the color parameters from distinct apertures. However, due to the heterogeneity of the granite the color is evaluated better with larger apertures. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012 相似文献
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In a text dating between 1259 and 1277, the Persian scholar al‐Tusi presented a systematic arrangement of 26 color terms. We propose a reconstruction of all color terms from al‐Tusi's scheme, in terms of preferred translation, mean CIEL*a*b* coordinates and digital representation. This reconstruction is based on a visual experiment with 30 subjects, who identified the Munsell chip best representing each color term. Persian words for which the meaning changed since the time of al‐Tusi were substituted by direct translations. The results show considerable interobserver variability in the colors selected when identifying color terms. This relatively large variation was shown to be a characteristic for memory matching experiments in general. Several specific color terms for which the resulting color variation was particularly large are discussed in more detail, and possible explanations for these variations are proposed. The proposed reconstruction suggests that al‐Tusi's list is largely consistent in modern colorimetric terms, although some large hue shifts are observed for color terms corresponding to green. We found no evidence for blue‐green (“grue”) confusion. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 206–216, 2016 相似文献
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To prevent the photodegradation process, a wide range of coatings have been developed. This study evaluated wood color change (ΔE*) and the surface quality index (SQI) generated by ASTM D‐660 standards in wood protected with polyurethane and varnish finishes of three tropical species (Acacia mangium, Cedrela odorata and Tectona grandis) in two weathering conditions (natural and accelerated condition). In addition, a model was developed to predict ΔE* and SQI in natural weathering based on ΔE* and SQI from accelerated weathering. The results showed that the application of these finishes generated variations in the color parameters of wood before being exposed to the elements. Additionally, it was found that finishes generated increases in ΔE*, especially the varnish type finish, and decreasing of SQI. Finally, models were found to predict color changes or surface quality in natural weathering based on color changes or surface quality in accelerated weathering. The model algorithm was expressed by ΔE* or SQI measured (X) and time exposure (t) in accelerated weathering by equation . With these models, it is possible to predict the equivalence of exposure times in natural weathering in tropical conditions for different kinds of finishes in three tropical species. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 519–529, 2014 相似文献
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Maria E. Nadal Edward A. Early Will Weber Robert Bousquet 《Color research and application》2008,33(2):94-99
The NIST 0:45 reflectometer measures the spectral reflectance factor at an influx angle of 0° and an efflux angle of 45° of colored, nonfluorescent specimens at room temperature, with widths ranging from 3 to 10 cm and heights from 3 to 20 cm and with an uncertainty of less than 0.5 in color difference units. Published in 2008 by John Wiley & Sons, Inc. Col Res Appl, 33, 94–99, 2008 相似文献