bluuebunny/crossref_metadata_2025_split huggingface dataset:
The conceptual NCS: An empirical investigation
Authors: Whitfield T. W. A. , Powell A. S. , O'Connor M. , Wiltshire T. J. 
Published: June 2007

AbstractTwo interesting features of the Natural Color System (NCS) are (a) the clear distinction made between the conceptual and atlas versions of the system and (b) the unique status attributed to the conceptual version. The latter finds expression in the claim that the system can be used without reference to atlas samples. In other words, it is claimed that subjects trained in the NCS perform with a high degree of accuracy in colour identification tasks using only their conceptual model for reference. The study reported here is a replication of experiments cited as support for this claim. Subjects were trained in the NCS using NCS training material and carried out colour‐identification tasks. For comparison, a further subject group was trained in the Munsell system and carried out identical tasks. The results indicated (a) a lower level of accuracy than previously reported for those subjects trained in the NCS and (b) little difference in performance between the NCS‐ and Munsell‐trained groups.
The fry uniform chromaticity scale diagram
Authors: Fry Glenn A. 
Published: June 2007

AbstractIn 1945 I created a uniform chromaticity diagram which was a modification of the 1931 CIE Chromaticity Diagram. At that time I tried to relate it to a modulation theory of color vision which has proved to be untenable. In 1965 I switched to a zone theory of color vision which provides a more acceptable physiological basis for my UCS diagram. In the present article I want to explain how the two are related. I make use of three diagrams. The first (my uv diagram) is a color mixture diagram which deals with responses of the cones. The second (my un vn diagram) deals with the yellow‐blue and red‐cyan signals generated in two separate sets of fibers of the optic nerve. It is this independence which permits the relation between u″ and u on the one hand and between v″ and v on the other to be nonlinear. This is my UCS diagram. It yields better uniformity of discrimination steps across the diagram than is possible with a projective diagram. The second diagram is designed to deal with discrimination at the threshold level. The third diagram (my m n diagram) deals with the suprathreshold spacing of the Munsell colors. It is produced by scissoring the two sets of coordinate lines of the u″ v″ diagram around the standard stimulus C. This is related to the way in which signals in the two sets of fibers mix to produce intermediate colors.
Physiological causes of individual variations in color‐matching functions
Authors: Nayatani Yoshinobu , Takahama Kotaro , Sobagaki Hiroaki 
Published: June 2007

AbstractThe present study confirms that the individual variations of Stiles' 20 color‐matching functions are physiologically well predicted by those of eye lens and macular optical densities. The principal‐component analysis of the blue color‐matching functions shows the significance of the two independent spectral components, which are expected to correspond to lens and macular optical densities. The lens and the macular densities for each of Stiles' 20 observers are estimated by using their published data physiologically measured. The estimated densities predict well each of Stiles' 20 color‐matching functions. The singular‐value decomposition of the estimated 20 color‐matching functions provides a good estimate of the standard‐deviate observer derived from the original Stiles 20 color‐matching functions by using the same procedure.
Field trials on color appearance of chromatic colors under various light sources
Authors: Nayatani Yoshinobu , Takahama Kotaro , Sobagaki Hiroaki 
Published: June 2007

AbstractField trials of the nonlinear color‐appearance model and the nonlinear chromatic‐adaptation transform were done on the effect of chromatic adaptation between illuminants C and A, and also on the visual estimations by Mori and Fuchida under five fluorescent lamps. The model could give reasonably good predictions to the visual estimations in the above two conditions. In addition, the present study confirmed that the nonlinear color‐appearance model and the nonlinear chromatic‐adaptation transform could better predict the chromatic‐adaptation effect between C and A than the von Kries law.
Influence of chroma and hue on spatial balance of color Pairs
Authors: Morriss Robert H. , Dunlap William P. 
Published: June 2007

AbstractEarlier research has shown that the relative chroma (saturation) of color pairs affects the relative areas of those colors that appear balanced in a predictable way. Small areas of high chroma balance large areas of low chroma. The present study shows that this chroma effect is independent of the background the colors were viewed against, and relatively independent of the hues involved. In particular, the chroma effect is as strong for hue pairs adjacent or intermediate on the color circle as for complementary hues. Finally, this study compared Munsell's theory of spatial balance to that of Moon and Spencer, finding better agreement with the former.
Calibration of a computer controlled color monitor
Authors: Brainard David H. 
Published: June 2007

AbstractBecause of the large number of stimulus configurations that may be displayed on a computer controlled color monitor, direct measurement of the relation between the digital input values to the frame buffer and the output of the monitor is not possible. To calibrate a monitor, it is necessary to make assumptions about the monitor's performance. These assumptions allow the monitor's output for any set of input values to be predicted from the input values and the results of a feasible number of calibration measurements. This article describes a set of assumptions that are sufficient to render the problem of monitor calibration tractable. These are the assumptions of phosphor constancy, phosphor independence, spatial independence, and the single scale factor assumption. If these assumptions hold, a monitor may be calibrated by measurements of the phosphor spectral power distributions, measurements of the phosphor input‐output relations, and measurements of the spatial scale factor at a number of locations. Violations of these assumptions limit the accuracy of calibration. The results of measurements that test the validity of these assumptions for a Barco 5351 monitor are presented.
Colorimetric principles applied to designing test kits for medical diagnosis
Authors: Norrington F. E. 
Published: June 2007

AbstractMany diseases involve the introduction into the body of highly specific foreign substances (antigens) to which the body responds by producing complementary antibodies. A test method has been developed whereby several different antigens can be detected simultaneously. One drop of fluid (e.g., blood serum, urine, saliva, etc.) from the patient is mixed with one drop of reagent on a card. Within two minutes a colour change takes place, each colour developed being diagnostic of a particular antigen. This paper describes the test and shows how colorimetric methods were used to optimise its performance, standardise the materials used, and determine the requirements for proposed further development.
A novel method for the determination of color matching functions
Authors: Fairchild Mark D. 
Published: June 2007

AbstractAn instrument was developed for the psychophysical measurement of color matching functions. The instrumental design centers around the use of lasers as the primary light sources. The three (RGB) laser beams are independently controlled with acousto‐optic modulators and projected into a diffuser for color mixing. The instrument was designed to allow for free viewing of the matching fields and versatility in the implementation of the matching fields and surround. To simplify data collection, a model was developed that allows the computation of the full spectral tristimulus functions based on just five visual matches. This model expresses color matching functions as linear transforms of the cone action spectra multiplied by variable transmittances of the lens and macula. The model was tested using the 2° color matching data of Stiles and Burch, and preliminary data were collected and modeled using the new instrument.
Hue shifts in unrelated and related colours
Authors: Hunt R. W. G. 
Published: June 2007

AbstractPublished data on the dependence of hue on luminance (the Bezold‐Brücke effect) is analysed in terms of changes of hue angle instead of changes in wavelength so as to assess their visual importance. For unrelated colours, for a given monochromatic wavelength, the changes in hue caused by altering the luminance vary appreciably according to whether the colours are seen side‐by‐side continuously, or side‐by‐side in flashes, or one‐at‐a‐time in flashes. For related colours, for a given chromaticity, the changes in hue caused by changing the luminance factor are examined in the Munsell and NCS systems; although systematic variations occur, they are different in the two systems, and in neither case is there any similarity to the situation for unrelated colours. Changes in illuminance on related colours do not seem to have any systematic effect on hue for a given chromaticity. It is concluded that the Bezold‐Brücke effect for unrelated colours is not relevant when related colours are considered.
Variance‐based color image quantization for frame buffer display
Authors: Wan S. J. , Prusinkiewicz P. , Wong S. K. M. 
Published: June 2007

AbstractColor image quantization is a process of representing an image with a small number of well selected colors. In this article an algorithm for multidimensional data clustering (termed the variance‐based algorithm), based on the criterion of minimization of the sum‐of‐squared error, is applied to the problem of reducing the number of colors used to represent a given color image. The suitability of the sum‐of‐squared error criterion for measuring the similarity between the original and quantized images is examined using a digitized image and a computer‐generated image. The experimental results indicate that this error measure is basically consistent with the perceived quality of the quantized image. The performance of the variance‐based algorithm is compared with that of other algorithms for color image quantization in terms of quantization images generated using the colors selected by the variance‐based and the mediancut algorithms are also presented.
Historical development of CIE recommended color difference equations
Authors: Robertson A. R. 
Published: June 2007

AbstractIn 1976 the CIE recommended two colour difference formulae, the CIELAB and CIELUV formulae, to promote uniformity of practice pending the development of a better formula. While some of the arguments in favour of the recommendation were political, there were also sound technical reasons for choosing the two formulae. The discussions leading to the recommendation and the reasons that led the CIE to its decision are reviewed. In particular the reasons for the modification of the 1964 (U*, V*, W*) formula to arrive at the CIELUV formula are given, and the derivation of the constants (116, 16, 500 and 200) in the CIELAB formula is explained. Most of the data presented are taken from CIE Committee minutes and correspondence.
Parametric effects on surface color‐difference evaluation at threshold
Authors: Witt Klaus 
Published: June 2007

AbstractExperiments on thresholds of perceptible color‐difference at CIE color centers have been extended for the parametric effects of the lightness of an achromatic surround and of a separating gap between a pair of painted specimens. Components of perceived color‐difference (hue, chroma, lightness) approximately could be assigned to geometric elements of threshold ellipsoids and used for component analysis. A study of ellipsoid and city‐block modelling revealed ellipsoid to be slightly better. An increase of total threshold by changed lightness of the achromatic surround was found only in the case of the dark CIE Blue, but in every case a gap increased threshold the darker the CIE color center. The results can be used for a correction in color‐difference evaluation.
Categorical color rendering of four common light sources
Authors: Boynton Robert M. , Fargo Lee , Collins Belinda L. 
Published: June 2007

AbstractSubjects were asked to sort samples from the Optical Society of America (OSA) Uniform Color Scales set into 33 color categories under four separate illuminants: tungsten‐incandescent, metal halide, high‐pressure sodium, and clear mercury. Sorting required that each color sample be designated as a “good,” “acceptable,” or “poor” example within one of the eleven basic color categories specified by Berlin and Kay. Three indices of the categorical color‐rendering capacity of the sources were developed. Assuming tungsten‐incandescent as the reference illuminant, all three measures rated the color‐rendering quality of the tested illuminants from best to worst in the order listed above, in agreement with the CIE color‐rendering index.
European practices and philosophy in industrial colour‐difference evaluation
Authors: McDonald Roderick 
Published: June 2007

AbstractA survey has been made of the use and methods of Instrumental colour difference measurement in quality control of colour within Europe. Several colour differnce formulae are in use. The performances of the most used formulae, namely CIELAB, CMC, BFD, M&S, and Datacolor, are compared. The degree of implementation of colour difference measurement in the textile, leather, automobile, and coatings industries is summarised. The use of new computer graphics to ensure continuity of colour from batch to batch and the alternative methods of colour sorting to minimise colour differences between batches are described.
Evaluation of a simple method for color monitor recalibration
Authors: Lucassen Marcel P. , Walraven Jan 
Published: June 2007

AbstractAn algorithm for recalibrating a color monitor's RGB input‐output relations is presented that requires only a single measurement of a properly chosen reference stimulus. For the application under concern, i.e., reproduction of 35 different colored patches that were used as stimuli for psychophysical experiments on color constancy, the reference stimulus was a white (D65) presented at a luminance corresponding to the mean of the test stimuli. Three sets of data were obtained for evaluating the algorithm's error reduction power for a given stimulus configuration. These relate to different ways in which the monitor can get out of calibration. That is, slow, but cummulative changes over time, fast changes dur to gun interaction (resulting from changed stimulus conditions), and error introduced by a different setting of the monitor's brightness control. Additional experiments were performed to evaluate the effect of background intensity and color. The algorithm was found to be quite effective in dealing with the instantaneous changes (gun interaction, brightness control), and also for keeping track of the slow changes that may finally necessitate a full recalibration of the monitor.
A colour notation conversion program
Authors: Smith N. S. , Whitfield T. W. A. , Wiltshire T. J. 
Published: June 2007

AbstractA computer program has been developed that converts between the notations of the Munsell, OSA‐UCS, NCS, DIN, and Coloroid colour order systems and the CIE, CIELAB, and CIELUV colour specification systems. The intention of this article is to outline the development of this program and its structure. Particular attention is given to the accuracy of the program and its associated databases.
Lightness perception of chromatic object colors
Authors: Nayatani Yoshinobu , Umemura Yoshifumi , Sobagaki Hiroaki , Takahama Kotaro , Hashimoto Kenjiro 
Published: June 2007

AbstractA hypothesis is proposed to predict the perceived lightness of chromatic object colors, which is well known as the Helmholtz‐Kohlrausch effect or the lightness‐reflectance ratio effect (L/Y effect). The hypothesis is, “When two chromatic object colors with different hues have the same values for each of three attributes (whiteness, blackness, and chromaticness), the two colors have the same perceived lightness, including a chromatic‐component contribution.” The hypothesis is tested by two kinds of experiments: perceivedlightness matching using the NCS Color Atlas, and chromatic tiles determined by Wyszecki. Both results strongly confirm the hypothesis. Further, contour lines of constant L/Y ratios are estimated, and are very similar to those reported previously.
Field trials for assessing the method of observer metamerism adopted by CIE
Authors: Nayatani Y. , Tanaka T. , Sobagaki H. , Takahama K. , Hashimoto K. 
Published: June 2007

AbstractThe following field trials are made for assessing the method of observer metamerism adopted by CIE. (1) The individual variation of metameric match was assessed between a fluorescent‐lamp light and each of three different matching stimuli by the CIE method. The high precision of visual color match was confirmed for the 6‐primary Donaldson colorimeter. The prediction was compared with experimental results for a similar fluorescent lamp. (2) The individual variation predicted by the CIE method was compared with that directly derived by using the Stiles original 20 color‐matching functions. The effectiveness of the CIE method was confirmed. (3) It was clarified that the individual variation of colorimetric values on a single test stimulus corresponds to that for the metameric match between the test stimulus and a mixture of the CIE 10° r, g, b primaries. (4) The actual observer variation found by Stiles and Wyszecki in the field trial on the CIE 1964 color‐matching functions was tested using the CIE method. The method is effective to assess the intrusion of other factors in actual color match, in addition to the individual variation of color‐matching functions.
Hue cycle described by graphs and color names
Authors: Pridmore Ralph W. 
Published: June 2007

AbstractThe color appearance of the hue cycle in equal radiance is described in hue, saturation, and brightness/lightness. The latter does not resemble CIE luminance Y (peaking at 555 nm green), but peaks near 570 nm yellow with minor peaks near 490 nm cyan and 530 c magenta. Saturation per watt peaks near 450, 530, 610 nm (blue, green, red). Newton's choice of seven spectrum colors, and particularly his two bluish colors, is explained as major colors rather than merely different hues.
Revised colour‐appearance model for related and unrelated colours
Authors: Hunt R. W. G. 
Published: June 2007

AbstractTo provide a more realistic balance between the relative contributions from cones and rods to the achromatic signal, at various levels of adaptation, revisions have been made to a previously published model of colour vision. Visual areas denoted as the adapting field, the surround, the background, and the proximal field have also been defined. Several minor changes have also been made to make the model more convenient to use. The steps required in using the model are described, and worked examples are included for both related and unrelated colours. For related colours, the differences between the original and revised models are fairly small in the results obtained for samples viewed on grey, or typical average‐scene, backgrounds, at normal photopic levels of illumination, except for lightness and chroma; but for light and dark backgrounds, more wide‐spread changes occur. For unrelated colours, the revised model includes the Bezold‐Brücke dependence of hue on luminance. The predictions given by the model are compared to physiological and psychophysical experimental data.
A system of mesopic photometry
Authors: Trezona P. W. 
Published: June 2007

AbstractThis paper describes a system of photometry designed to make no unjustifiable assumptions, and to have a strong visual linkage. It spans the photopic, mesopic, and scotopic regions and is based on brightness matching a 10‐degree field, centrally fixated. An intensive investigation was made on the trichromator at the National Physical Laboratory, Great Britain, and an extensive one, using a greater number of observers, on the trichromator at the National Research Council, Canada. A bipartite field allowed equal brightness settings of the aperture colour by each of nine observers. The stimuli tested were both spectral and nonspectral and the data were used to derive formulae which a user could employ. From inserting conventional photometric quantities of a stimulus, which might for example be a light source, the user can obtain its corresponding photometric value whether it be photopic, mesopic, or scotopic.
Discrimination ellipsoids of aperture and simulated surface colors by Matching and paired comparison
Authors: Indow T. , Robertson A. R. , Von Grunau M. , Fielder G. H. 
Published: June 2007

AbstractDiscrimination ellipsoids were constructed in the (x, y, Y) space for six colors so: achromatic, red, yellow, green, blue, and brown. the colors were presented on the surround, either dark (aperture color mode) or bright (simulated surface color mode). Ellipsoids were defined by two methods: matching and paired comparison (an extended form of the method of constant stimuli). Hence, four ellipsoids were obtained with so by each of two observers. For simulated surface colors, except for the yellow color, the two methods gave almost the same ellipsoids. Ellipsoids defined by the fluctuation of matches were almost the same for both aperture and simulated surface colors. Those ellipsoids are similar on the chromaticity diagram to ellipses estimated through MacAdam's colormetric coefficients g's. Paired comparisons were more difficult for aperture colors than for simulated surface colors in the sense that the ellipsoids were larger in size. However, the rates of false discrimination for identical pairs (so, so) were higher for surface colors. In spite of the drastic change of appearance of the brown color, no change was observed between the two modes of appearance for ellipsoids obtained by either method. the study is methodological and detailed statistical analyses of the two data processings are included, one based on matchings and the other based on paired comparisons.
Estimation of luminance factor from cie supplementary standard colorimetric observers
Authors: Ohta N. 
Published: June 2007

AbstractThe luminance or luminance factor is not defined in the large viewing field greater than 4° since the color matching function ȳ10(Λ) is not identical to the spectral luminous efficiency V(Λ). the possible errors are estimated when ȳ10 (Λ) is used in place of V(Λ) for evaluating the luminance factor.