bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficiency and uniformity comparisons between a diffusing‐optics source and a lamp‐imaging source
Authors: Spadaro John 
Published: June 2007

AbstractIntegrating spheres, when used in a light source, offer a highly uniform illuminated area and, when used in conjunction with a reflective diffuse sleeve, can offer effeciencies equivalent to that of a lamp‐imaging reflector system. The diffuse sleeve provides a means for the sphere to use light normally lost while maintaining a beam that is substantially more uniform than the reflector system. This article describes a test comparison between a modified diffuse integrating sphere source and a lamp‐imaging optics source.
Determination of correlated color temperature based on a color‐appearance model
Authors: Walter Wolfgang 
Published: June 2007

AbstractThe present method of determining the correlated color temperature of an illuminant is based on the obsolete CIE 1960 u,v chromaticity diagram. A new method is proposed that is based on Hunt's color‐appearance model for unrelated colors. Analytic functions were derived for the blackbody locus in appearance space to simplify the computation. CCT was calculated for some light sources and the results were compared to those obtained by the present method.
Color rendering of supplementary artificial lighting
Authors: Embrechts J. J. 
Published: June 2007

AbstractMany interiors may be lit by daylight and artificial light; the CIE color rendering index (CRI) of the sources alone is not a characteristic of the complex situation. It is the purpose of this article to derive the general principles leading to the determination of the CRI distribution in such an interior. the CRI is expressed as a function of the proportion α of the combination, for several types of daylight and artificial light. It is shown that the dependence of the CRI on α is linear for supplementary artificial lightings which have the same chromaticity as daylight. Otherwise, nonlinearities are introduced. the time variation of the CRI is also analyzed.
Color classification of natural color images
Authors: Tominaga Shoji 
Published: June 2007

AbstractThe present article describes a color classification method that partitions a color image into a set of uniform color regions. The input image data are first mapped from device coordinates into the CIE L*a*b* color space, an approximately uniform perceptual color space. Colors used to represent a natural color image are classified by means of cluster detection in the uniform color space. The basic process of color classification is based on histogram analysis to detect color clusters sequentially. The principal components of a color distribution are extracted for effective discrimination of clusters. We present an algorithm for sequential detection of color clusters in the uniform color space, and the related algorithms for region processing and color computation. The performance of the method is discussed in an experiment using three kinds of natural color images.
Toward a more accurate and extensible colorimetry. Part Iii. Discussion (continued)
Authors: Thornton William A. 
Published: June 2007

AbstractThe instrument used to gather the data of this article, a bright split‐field visual colorimeter coupled by quartz light pipe to a spectroradiometer, generated many pairs of lights visually‐matching to one of six normal human observers. an accurate absolute spectral power distribution (SPD) was obtained for every such viewed light. Three disparate primary‐sets were used. Large errors in chromaticity and brightness (represented by luminance), computed by the 1964 CIE Standard Observer, were found to pervade the results. Problems are introduced by the use of maximum‐saturation CMFs, by transformation of primaries, by the structure of the CIE chromaticity diagram, and by measurement inaccuracies of the far past. In Part III, alternative derivations of weighting functions, multiplied against the absolute SPDs of the visually‐matching lights to obtain what are called tristimulus values, are shown to reduce errors in computed chromaticity. an alternative brightness function, of complexity commensurate with that of the three‐input normal human visual system, is shown to correlate considerably better to perceived brightness of white and colored lights than does computed luminance. an alternative chromaticity diagram is constructed of two chromatic terms of the brightness function, as a constant‐perceived‐brightness plane (which conventional diagrams are not), and avoids problems inherent in the conventional diagram.
The Colorcurve Systems®
Authors: Stanziola Rulpha 
Published: June 2007

AbstractThe Colorcurve System is first and foremost a system for color communication. It provides a direct means of communication between spec (fiers or creators of color and the manufacturer of colored products. It is a combination of a visual and numerical system. The system is made up of four main elements: (1) Aim points in CIE L*a*h* color space; (2) Physical representation of the aim points; (3) Data tables and numerical descriptions of the aim points; and (4) Computational methods andlor computer software. A simple notation system that can be easily understood by both creative people and industrial technologists was developed. The numerical description of each aim point can aid manufacturers in getting acceptable color matches in a variety of materials because it fits in with the procedures used for computer color matching. © 1992 John Wiley & Sons, Inc.
Colour appearance of stained glass windows
Authors: Schanda J. D. 
Published: June 2007

AbstractThe ruby reds and the strong blues of the stained glass windows of Romanesque and Gothic cathedrals are some of the most magnificent pieces of craftsmanship mankind has produced. According to our knowledge, no colorimetric attempt has been made to understand the visual impression produced by them. Modern colour‐appearance models permit the description of the colour impression produced by chromatic stimuli under changing adaptation conditions. In the present article, an attempt is made to model the visual situation and to use the colour‐appearance model developed by Nayatani and co‐workers for colorimetrically describing the observed effects. In model experiments, “extra brightness” was found when changing the direction of view from the dark surrounding to the well lit stained glass window. Calculations based on the Nayatani model yielded similar extra brightness and extra colourfulness, in good agreement with visual observations.
Confusion lines of dichromats
Authors: Fry Glenn A. 
Published: June 2007

AbstractA way has been found to plot the mixture data of a protanope or a deuteranope on a constant luminance mixture diagram to show that the confusion lines are parallel to the line tangent to the red end of the spectrum locus. In the case of a tritanope the confusion lines are parallel to each other on a constant luminance diagram. These constant luminance diagrams are projective transformations of the CIExy diagram. My confusion lines converge close to the copunctal points located by Walraven on the CIE diagram. © 1992 John Wiley & Sons, Inc.
Suggested modification of CMC formula for acceptability
Authors: Brill Michael H. 
Published: June 2007

AbstractThe Colour Measurement Committee [CMC] formulas for color‐difference acceptability do not describe ellipsoids in CIELAB space, but the literature describes the acceptability surfaces as ellipsoids. It turns out that the discrepancy does not affect computational results [as long as the CMC parameter c is 1]. However, if the ellipsoid equations were substituted for the existing quartic formulas, the possibility for conceptual confusion would be much reduced. © 1992 John Wiley & Sons, Inc.
Determination of colorcurve colour atlas sample deviation and comparison with NCS, DIN and OSA‐UCS atlas sample deviation
Authors: Smith N. S. 
Published: June 2007

AbstractThis article presents an evaluation of the deviation of the Colorcurve atlas samples from their designated aim points. Sample deviations are evaluated in terms of hue, chroma, and lightness. In addition, the deviation of the Colorcurve samples from their respective aim points are graphically represented for eighteen lightness levels, Comparison is provided with NCS, DIN, and OSA‐UCS atlas sample deviation.
Comparison of colorimetric and spectrophotometric algorithms for computer match prediction
Authors: Sluban Boris 
Published: June 2007

AbstractThe article discusses two types of colour‐formulation strategies: the tristimulus colorimetric strategy (ΔX,ΔY,ΔZ) → (0,0,0) and the least‐squares curve fitting Σjw2j[ΔR(λj)]2 → min. Then a new matching strategy (ΔED65)2 + (ΔEA)2 + (ΔEWWF)2 → min is stated, which tries to combine the advantages of the first two strategies: more “balanced” colour differences for several different illuminants (the case of curve fitting) and small colour differences for the illuminant involved in the matching process (the case of tristimulus matching). An algorithm following this new general strategy is constructed using the case of single‐constant Kubelka‐Munk theory as an example. Results of a few numerical experiments are included for illustration.
Colorcurve and coloroid notations for the OSA‐UCS atlas samples
Authors: Smith N. S. 
Published: June 2007

AbstractColorcurve (D65/1964) and Coloroid (C/1931) notations of the 558 OSA‐UCS atlas samples are presented in two tables. One table provides the Colorcurve and Coloroid notations for the 424 regular samples; the other for the 134 near‐neutral (half‐step) samples. Colorcurve notations are derived from the OSA‐UCS aim points, and Coloroid notations are derived from colorimetric data of the OSA‐UCS samples contained in MacAdam's copy of the OSA‐UCS colour atlas.
Measuring color‐matching functions. Part I
Authors: North Amy D. , Fairchild Mark D. 
Published: June 2007

AbstractA visual colorimeter was designed to implement a new model for the determination of color‐matching functions developed in the Munsell Color Science Laboratory. An instrument utilizing laser primaries was originally developed. The instrument was later improved to incorporate CRT primaries and seven interference filters to make matches to simulated daylight in a 2° bipartite field. The system was designed to minimize the strain on observers. Color‐matching functions of naïve observers can be measured in approximately 30 minutes. Results from an individual observer correlate well with data collected on the National Research Council of Canada's Trichromator. Part II of this article gives the color‐matching functions results for 18 observers and 20 repetitions by a single observer.
Illuminance dependency of L/Y (lightness/luminance‐factor)‐ratio effect
Authors: Nayatani Yoshinobu , Sobagaki Hiroaki , Hashimoto Kenjiro 
Published: June 2007

AbstractUsing a modified model for predicting the perceived lightness of chromatic object colors for various adapting illuminances, the following two kinds of predictions were done for seven illuminance levels from 2 to 3000 lx on the basis of the Wysecki data. One concerned the contour lines of equal L/Y (lightness/luminance‐factor) ratios in the whole chromaticity gamut, and the other the values of L/Y ratios for spectral colors. All the colors predicted have tristimulus value Y = 20. The computed results confirmed that the difference of L/Y‐ratio effect found between the Wysecki and the Sanders‐Wyszecki experiment was caused by the difference of the test adapting illuminance between them.
Image color‐appearance specification through extension of CIELAB
Authors: Fairchild Mark D. , Berns Roy S. 
Published: June 2007

AbstractAn extension of the CIE 1976 (L*, a*, b*) color space, CIELAB is described for applications in color reproduction. This extension incorporates a more accurate model of chromatic adaptation, capability to distinguish between the modes of appearance of reflective and self‐luminous stimuli, and adjustments to account for changes in surround. The extension of CIELAB is referred to as the RLAB color space. This color space can be used for calculating metrics of lightness, chroma, hue, and color difference. It can also be used to determine the required colors for reproduction across changes in media and viewing conditions. A pilot experiment testing the RLAB model for cross‐media color reproduction is also described.
Quantifying colour appearance. part IV. Transmissive media
Authors: Luo M. Ronnier , Gao X. Wang , Rhodes Peter A. , Xin H. John , Clarke Anthony A. , Scrivener Stephen A. R. 
Published: June 2007

AbstractThe experimental data from this study extends the LUTCHI colour‐appearance data to cover transmissive media. Two further experiments were carried out: one used a large cut‐sheet transparency viewed using a back‐lit illuminator, and another used a 35‐mm slide projected onto a white screen. These new data were used to reveal the changes in colour appearance caused by different viewing parameters studied, and to evaluate the predictive accuracy of five uniform colour spaces and colour‐appearance models. The results show that Hunt's 91 model (developed to fit earlier experimental results) did not perform as well as it did in the previous studies using nontransmissive media. This implies that there are large differences in perceived colour appearance between transmissive and nontransmissive media viewing conditions. Some modifications were subsequently made to Hunt's 91 model and the predictive accuracy was greatly improved.
Problems connected with the concept of gloss
Authors: Sève Robert 
Published: June 2007

AbstractA summary of the most recent ideas about gloss is presented with specific attention to the problems raised by the evaluation of perceived gloss with physical quantities. Research work published on the problem of multidimensionality of gloss, as well as methods using several parameters to characterize gloss, are first mentioned. Then physical phenomena related to gloss are discussed from the points of view of physical optics, geometrical optics, and photometry. Experimental results are related to the theory. It is shown that a mirror element reflects light in such a way that its radiant intensity in the specular direction is independent of its area, contrary to the radiant intensity scattered by an isotropic diffuser. The consequences of this fact for the current measurement of gloss are developed, mainly, the arbitrary choice of any gloss scale. A proposal is made to relate the measured gloss to the luminance factor in the specular direction. Problems raised by the terminology are also discussed: terms are needed for the general phenomenon of gloss, for the perceptual aspect of gloss, and for the most widely measured photometric quantity related to gloss. Proposals for future work are made.
Objective evaluation of color design. II
Authors: Kawamoto Naoki , Soen Toshiichi 
Published: June 2007

AbstractA method to predict psychological values of color design was derived from our experimental data on 30 random color patterns previously published. This method, based on the two‐dimensional Fourier transform of color patterns, was designed to evaluate psychological values of the pattern in terms of 13 rating scales such as “beautiful‐ugly,” “warm‐cold,” “hard‐soft,” and so on. It was found that the psychological values of random color patterns could be evaluated in terms of zero‐frequency (average color) and low‐, medium‐, and high‐frequency components of the Fourier transform of the patterns. Applicability of the evaluation method to predict psychological impressions of real color design was tested with results from a new experiment on some fabric design that is described in this article.
Color‐rendering capacity of light
Authors: Xu H. 
Published: June 2007

AbstractTwo types of questions, both related to color‐rendering properties of light, can be identified. Type A: Given a spectral reflectance chip under illumination of a certain spectral power distribution, What color can appear? Does the appearing color, in comparison with a reference one, look right or distorted? Type B: Given a great many chips of different spectral reflectance functions under illumination of a certain spectral power distribution, How many different colors, no matter what colors, can appear? Are there a great many different colors or just a few different colors appearing? Questions of type A reflect an important aspect of color‐rendering properties and can be tackled with an established measure, the CIE color‐rendering index. Questions of type B, related to quite another aspect of color‐rendering properties, have particular relevance when illumination's function of making things visible is of most concern. This article discusses a new measure, the color‐rendering capacity (CRC), developed for dealing with questions of type B, and explains the measure's derivation, calculation, and implications.
Categorized color space on CRT in the aperture and the surface color mode
Authors: Shinoda Hiroyuki , Uchikawa Keiji , Ikeda Mitsuo 
Published: June 2007

AbstractThe study was made for structure of categorized color space in the aperture and the surface color modes. The color appearances of two modes were reproduced on a CRT display with or without a surround configuration. Subjects made categorical color naming with 11 basic color terms. The (x,y,L) color space divided with these terms showed structural difference between the two modes. This result indicates that color is categorized by only chromaticity in the aperture color mode but by luminance and chromaticity in the surface color mode. © 1993 John Wiley & Sons, Inc.
On obtaining shape from color shading
Authors: Petrov A. P. 
Published: June 2007

AbstractColor and Grassmann‐Cayley Coordinates of Shape are considered in this article. The image irradiance equation for colored surfaces and the Grassman manifold λ of orbits Q = {B · h + c; detB ≠ 0} Where c is a vector sweeping the color space H, B is a 3 × 3 matrix, and h(x, y) is the color image of a Lambertian surface assumed to be a linear vector‐function of the normal vectors. Different orbits Q(n) correspond to different shapes but they are invariant under color and illuminant transformation. Coordinates of an orbit Q in λ can be computed as 3 × 3 (2 × 2, sometimes) determining the elements of which are values of some linear functionals (receptive fields) of h(x, y). Based on the approach, a shape‐from‐shading algorithm was developed and successfully tested on the threeband color images of various real objects (an egg, cylinders and cones made of paper, etc.). © 1993 John Wiley & Sons, Inc.
Intersections of matching spectra: Applications
Authors: Thornton William A. 
Published: June 2007

AbstractResults of the preceding article are used to develop (1) a “characteristic” SPD of a light; (2) a method of spectral correction to remove the simple color difference in a pair of lights or reflectances that embody both metamerism and simple color difference; (3) characterization of typical spectral differences between SPDs of lights that match; and (4) a definition and procedure for specifying “degree of metamerism” of a pair of matching lights or reflectances. © 1993 John Wiley & Sons, Inc.
Lightness and reflectance of munsell gray samples
Authors: Xu H. 
Published: June 2007

AbstractA procedure has been designed, on the basis of the general‐type luminance difference threshold data, to find the maximum possible number of the distinguishable luminance levels (the MAX‐NUM‐OF‐LEVELS) between two given luminances with respect to observers under a certain adaptation state. Taking the MAX‐NUM‐OF‐LEVELS as a measure of visibility and applying the procedure to a study of lightness and reflectance of gray samples, it is found that the existing Munsell gray samples with Munsell values 1 to 9, which intend to appear equally spaced, can hardly be regarded as equally‐spaced in lightness, and a group of rearranged reflectances for these gray samples may improve the situation. © 1993 John Wiley & Sons, Inc.
Fuzzy set theory on car‐color design
Authors: Hsiao Shih‐Wen 
Published: June 2007

AbstractThe relationship between some colors of cars and their image sensation are investigated by using the fuzzy set theory. The color image a person has of a car is quantified using the membership function. A computer program is constructed to calculate and analyze the similarity relations of various colors and further to arrange the corresponding membership functions of colors to one image word by size. The results show that the man‐machine matching in color image is mostly dominated by the hue. The orderly table can be suggested to the designer for what color should be used if he can input the demanded image word (or words) for specifying the characteristic of a car in the stage of concept design. In such a way, not only can the error of a design decision be reduced, but the efficiency of the decision making can also be improved. Thus, it is indeed a powerful and valuable method for designing a product.
Modified CIELAB formula tested using a textile pass/fail data set
Authors: Witt Klaus 
Published: June 2007

AbstractThe proposed new color‐difference formula of CIE TC 129, which is a modified version of CIELAB, was tested with a recently published data set of textile pass/fail judgments. Goodness of fit is improved, if the parameter of lightness is set near 2, and if, additionally, a weight function for lightness is defined that reduces the weight of a lightness difference with lightness level in relation to chroma or hue scaling. © 1994 John Wiley & Sons, Inc.
Dichromatic reflection models for a variety of materials
Authors: Tominaga Shoji 
Published: June 2007

AbstractThis article proposes dichromatic reflection models adequate for describing surface‐spectral reflectances of a variety of materials. the standard dichromatic reflection model for inhomogeneous materials assumes that light reflected from an object's surface is decomposed into two additive components: the body reflection and the interface reflection, which is independent of wavelength. First, we present a method for testing the adequacy of this standard model based on the observations of surface‐spectral reflectances. the standard dichromatic reflection model is adequate for many materials. However, the test results point out that there are some cloths for which the standard model is inadequate, and metals that have only the interface reflection. Next, we extend the standard model to have an interface reflection component that depends on wavelength. an algorithm is presented for estimating two reflectance functions in the generalized model. Moreover, a dichromatic reflection model specialized for only the specular reflection is defined for approximating metal's reflection. the reflection characteristics are analyzed using a chromaticity diagram. It is concluded that surfacespectral reflectances of most materials are described by three types of the dichromatic reflection model. © 1994 John Wiley & Sons, Inc.
Spatial integration with chromatic stimuli in dichromatic vision
Authors: Kawabata Yasuhiro 
Published: June 2007

AbstractThe critical area of spatial integration was examined in dichromatic vision (protanope and deuteranope) by means of chromatic thresholds at equiluminance. The results showed that the critical area became smaller as the chromatic saturation of the background field was increased. Here, the chromatic saturation was defined by the colorimetric purity of the background field, multiplied by the saturation coeficient (Cs) of each dominant wave‐length. For the 470‐nm field condition, the trend of dichromatic data was similar to that of the previous data with normal subjects. For the 590‐nm condition, however, the decrease of integration area was less than that of the normal. This discrepancy can be attributed to the diference of saturation coeficients between normals and dichromats. © 1994 John Wiley & Sons, Inc.