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Nagy A L - - 1985
An alternation method of color matching was used to obtain a series of extended Rayleigh matches from several deutan color deficients with varying degrees of color discrimination. With large stimulus fields there were differences in the matches made by observers with good color discrimination and the matches made by observers ...
Jacobs G H - - 1984
A forced-choice discrimination procedure was used to test color vision and visual sensitivity in 10 squirrel monkeys (Saimiri sciureus) originating from three geographical locations (Bolivia, Colombia, Guyana). In agreement with results from an earlier study of vision in squirrel monkeys of Peruvian origin, striking individual variations in color vision were ...
King-Smith P E - - 1984
Acquired color deficiencies may correspond to a general, non-selective loss of visual sensitivity. We summarise evidence for the opposite view that, in some cases, chromatic sensitivity can be more (or less) reduced than achromatic sensitivity. This evidence is based on: (1) Disproportion between chromatic and achromatic isopters; (2) Differential damage ...
Nagy A L - - 1984
The additivity of color matches to short-wavelength lights was examined in observers who behaved as red-green dichromats under the stimulus conditions used. Color matches were obtained at several luminance levels and on several different adapting backgrounds. The range of mixtures acceptable as a match and the midpoint of this range ...
Grover P B PB - - 1984
Phototactic response rates in the aquatic crustacean Daphnia magna were found to increase greatly when cultured under a lighting regime that included simulation of sunset and sunrise. The changes in intensity and color of the crepuscular periods are known to be the primary stimulus for vertical migrations of many planktonic ...
Morrissette D L - - 1984
Thirty-six subjects completed questionnaires on their experiences wearing the CPF 550 lenses. Twenty-six subjects [21 with retinitis pigmentosa (RP)] were users of the 550's and 10 subjects (6 with RP) were nonusers who had rejected the 550's after a trial period. Subjects were asked about such factors as effects on ...
Rice D C - - 1984
Monkeys (Macaca fascicularis) were dosed po from birth with 500 micrograms/kg/day of lead as lead acetate. Blood levels peaked at an average of 55 micrograms/dl by 100 days of age, and dropped after 200 days of age to a steady-state level averaging 33 micrograms/dl. No overt signs of lead toxicity ...
Buchsbaum G - - 1984
We compute the gamut of coordinates in the Commission Internationale de l'Eclairage chromaticity diagram that correspond to positive frequency-limited functions having only three degrees of freedom (a trichromatic system). The results suggest that practical colors are either suitably frequency limited to be represented by three samples or have suitably frequency-limited ...
Ejima Y - - 1984
Dependence of the red-green and yellow-blue opponent-color responses on stimulus intensity was examined. First, each of four chromatic responses was measured as a function of illuminance by using a hue cancellation procedure. The cancellation redness and greenness increased proportionally with illuminance, but the cancellation yellowness and blueness did not. Second, ...
Ejima Y - - 1984
The neon color effect can be described as an illusory spread of color surrounding colored lines embedded in certain line gaps. The effect is seen in the Ehrenstein pattern if colored crosses are added to the central gaps so as to connect the inner tips of the pattern. Experiments were ...
Kolers P A - - 1984
Two shapes of either the same or different color will seem to be in smooth apparent motion with like-colored mates, at proper conditions of flash timing and spacing. An experiment is reported in which the condition was tested for unlike-colored pairs, for example red-green alternated with green-red. The question of ...
Jacobs G H - - 1984
Color vision was studied in 27 squirrel monkeys (Saimiri sciureus) of Peruvian origin (Roman Arch variety). Tests of wavelength discrimination and Rayleigh matching as well as a search for a spectral neutral point were carried out in a behavioral paradigm involving a three-alternative, forced-choice discrimination. Significant individual variations in color ...
Gilchrist A L - - 1983
Observers were asked to select samples from a Munsell chart to match the lightness of seven identified surfaces in an outdoor scene they were shown. A separate group that was given the same task but viewed the same scene covered with a veiling luminance equal in intensity to the highest ...
Koslow R E - - 1983
The subjects were 32 college student volunteers all assessed to have normal or corrected normal visual abilities. Each subject reacted to each of five variously colored balls 100 times per day over a 2-day period. These balls randomly appeared at one of four locations in the subjects' visual field. Analysis ...
Xu H - - 1983
A new measure called color-rendering capacity is developed, by applying some of the concepts used in communication engineering, to describe another aspect of the color-rendering properties of illumination, i.e., the maximum possible number of different colors that can be displayed by a given illumination. It is a relative measure expressed ...
Dorea J G - - 1983
Head hair of 150 normal boys from Brazil ranging in age from 1 to 12 years was studied for the influence of color on concentrations of zinc and copper. Hair color was classified visually and also quantified by melanin concentration. Visual classification and spectrophotometric measurements of melanin showed good agreement ...
Noorlander C - - 1983
Three-dimensional discrimination ellipsoids are presented for a number of representative points in color space. These ellipsoids have been obtained not with the conventional split field but with flickering grating patterns. Thus our study extends the well-known results of Brown and MacAdam [J. Opt. Soc. Am. 39, 808-813 (1949)] to cases ...
Ware C - - 1983
There is a discrepancy between several studies that have shown the human luminous-efficiency function to vary with surround color and a recent study that failed to find this dependence. Data are presented that show that this discrepancy can be explained by differences in the matching techniques. Luminous efficiency measured by ...
Richterman H - - 1983
The emphasis of this study encompasses two major areas: 1) light intensity, 2) color contrast. We were interested in this study to see how the manipulation of these two major variables might aid severely visually handicapped persons (legally blind) to be more productive and comfortable on the job. In the ...
Kovach J K - - 1983
One-day-old visually naive and experienced quail chicks (C. coturnix japonica) were mass-screened for approach preferences by pairs of stimuli that were identical in size and luminance but different in color, or pattern, or both color and pattern. Subjects were drawn from the 18th generation of quail lines that were bidirectionally ...
Kovach J K - - 1983
Approach choices were tested in genetically and environmentally manipulated quail chicks with pairs of stimuli identical in size and luminance but different in color, flicker, or both color and flicker. Data indicated comparable flicker and vastly different color preferences in subjects that were bidirectionally selected for color choices. In the ...
Ejima Y - - 1983
Red-green and yellow-blue chromaticnesses were scaled for various monochromatic lights by a just-noticeable-difference method. The just-noticeable difference of each chromaticness, i.e., redness, greenness, yellowness, or blueness, was defined by the change of the canceling light intensity that was required to produce a just-noticeable difference in the amount of the opponent-hue ...
Richards O W - - 1983
For over a hundred years, colored filters have helped people with less than normal color vision, to discriminate colors. Filtered light does not restore missing or abnormal pigments within the defective eye. Contrast and discrimination provided by a suitable colored filter can help discrimination of a given set of colors, ...
Neeley W E - - 1983
We have designed and constructed a digital matrix photometer for quantitative measurement of reflected light of small chromophoric areas or colored spots. The areas are divided conceptually into small subunits in which the reflected light is measured. This is done through stepwise scanning with a photodiode array. The sum of ...
Klemm W R - - 1983
In this study we evaluated in humans the question of whether contrast effects with patterned color stimuli varied in the same way as is known to occur with black-and-white stimuli. Using a counterphasing checkerboard pattern, we evaluated the steady-state visual evoked potential (VEP) in 10 subjects for the response to ...
Takahashi S - - 1983
Induced chromatic effects were determined for monochromatic, equal-luminance inducing stimuli from 460 to 680 nm by using a hue-cancellation procedure. The observed red-green-and yellow-blue-induced chromatic-response functions, which were different from the prediction based on the opponent-color hypothesis, could accurately explain the characteristics of the simultaneous color contrast effect. Good linear ...
Wolfe J M - - 1983
Isoluminant stimulus is an image whose edges are defined only by a change in color, not by change in brightness. The stimulus here is imperfect: the blue parts and the green parts of the image are only as nearly equal in brightness as they can be on the printed page. ...
Favreau O E - - 1983
Interocular transfer of a spatial frequency shift was obtained with equiluminous color gratings. Gratings which combined both color and luminance contrast yielded small aftereffects and no interocular transfer. Recent electrophysiological work has uncovered color-sensitive binocularly driven cells in visual cortex. These cells are transient and often respond to color contrast ...
Yaguchi H - - 1983
Heterochromatic brightness matches were carried out between bichromatic mixtures of lambda 1 and lambda 2, and a 100 td white reference light of 2 degrees arc. Two characteristic properties of additivity failure were observed. One is the asymmetrical property of additivity failure, that is a remarkable brightness reduction at the ...
Sabban Y - - 1982
The responses of different races to the colors used in the Pollimeter were examined. This scaling device is based on a movable visual element of one or two different colors permitting attitude, involvement, or choice to be measured on a continuous scale. The scores of Negroes and non-Negroes were highly ...
Smith E L - - 1982
Increment-threshold spectral sensitivity functions were determined during the dominance and suppression phases of binocular rivalry. The shapes of the functions obtained during the dominance phase exhibited three maxima at approximately 440, 530, and 610 nanometers and resembled functions obtained for nonrivalrous control conditions. However, the functions measured during suppression had ...
Adams A J - - 1982
Color vision changes may occur early in the course of glaucoma and may precede visual field loss. Glaucoma suspects, having raised intraocular pressure and no diagnostic optic nerve head or visual field changes, may also have color vision loss. Unfortunately, the instruments used in the studies that have demonstrated these ...
Uchikawa K - - 1982
With a modified step-by-step brightness-matching procedure, a series of colors, with dominant wavelengths from 400 to 670 nm, was adjusted so that the saturations and brightnesses of the colors appeared equal to those of the reference, which was a mixture of 570-nm and white light. The results show that equally ...
Burns S A - - 1982
The brightness of lights defined by heterochromatic flicker photometry as being of equal luminance was determined by direct comparison with a white standard. Stimuli included mixtures of white and colored lights. Eight different colorimetric purities were tested for each of eleven primaries. Adaptation to a known white was maintained. Resulting ...
Santucci G - - 1982
Three experiments were conducted on 90 flying personnel to determine the role of luminance, hue, and saturation contrasts on angular visual acuity measured on a CRT system. A Snellen E test object was displayed under various visual acuity conditions on a TV screen, in color contrast, using red, yellow, green, ...
Ayama M - - 1982
The amount of red chromatic valence of the red-green opponent colors channel of the human visual system has been reported to be greatly reduced in short wavelengths when the hue-matching method is used to measure red valence instead of the more typical cancellation method. Receptive fields with a silent surround ...
Ware C - - 1982
Studies of chromatic induction have generally examined either (a) the effects of a chromatic surround on a neutral test field, or (b) the effects of one spectral hue on another. To investigate how colors interact in other regions of color space an experiment was designed using fifteen test stimuli scattered ...
Rogers D C - - 1982
Binocular rivalry for a series of colored targets was measured in three trichomats and two red-green dichromats by cumulating those times when ony one target or the other was perceived (exclusive visibility time). Targets were black and colored 3 c/deg square-wave gratings, 1 degree in diameter. For trichromats, exclusive visibility ...
West G - - 1982
Necessary and sufficient spectral conditions are presented for Von Kries chromatic adaptation to give color constancy. Von-Kries-invariant reflectance spectra are computed for illuminant spectral power distributions that are arbitrary linear combinations of the first three daylight phases. Experiments are suggested to test models of color constancy using computed spectra (either ...
Krauskopf J - - 1982
Thresholds for detecting changes in color are raised following viewing a field sinusoidally modulated in color over time. This effect is highly selective. For example, thresholds for detecting reddish and greenish changes from white are raised following viewing a field varying in a reddish-greenish direction, but not after viewing one ...
Schwartz S H - - 1982
Reaction time distributions were determined in response to near-threshold intensity increments predicted to isolate either the opponent-color or luminance system. The reaction time histograms show a clear distinction between when the chromatic and achromatic systems detect the stimulus. Our results are consistent with previous reports suggesting the achromatic system is ...
Shevell S K - - 1982
Observers viewed a thin (0.8-1.3) annulus composed of a mixture of 540 and 660 nm monochromatic lights (denoted delta G and delta R, respectively). The annular mixture was superimposed upon a larger (2.7) 660 nm circular background field. The observer adjusted the radiance of either delta G or delta R ...
Kirk D B - - 1982
A close correlation between Stiles's increment threshold (pi-mechanism) approach and color discrimination at threshold was found: a sharp transition from detection of two lights via two pi-mechanisms (pi 1 and pi 4) to detection via only one pi-mechanism (pi 1) was paralleled by a sharp decline from excellent discrimination between ...
Redies C - - 1982
Van Tuijl's neon color effect arises in the Ehrenstein figure if a colored cross is added such as to connect the black arms across the central gap. The effect consists of a circular veil of color in the illusory area and has the same hue as the inducing cross. The ...
Cohen J B - - 1982
In 1953, Wyszecki described radiometric functions as composed of two components--a fundamental color-stimulus function and a metameric black function. The present paper discusses procedures for accomplishing the decomposition or resolution of any visual stimulus into these components. These methods rest on the fact that the color-stimulus space is a space ...
Blakeslee B - - 1982
Spectral sensitivity and color vision were investigated in 2 spider monkeys (Ateles) using a forced-choice discrimination paradigm. The increment-threshold spectral sensitivity functions of both animals were very similar to those of normal human trichromats; all had three regions of peak sensitivity located at 440-460, 520-540, and 670-620 nm. However, color ...
Pinckers A - - 1982
The classification of neutral grays is helpful for the differential diagnosis of color vision defects, especially when anomaloscopic examination is not possible. In congenital color vision defects the PR, RP region of the spectrum appears 'dark' to protan-defective subjects and 'light' to deutan-defective subjects. Acquired color vision defects have a ...
Worthey J A - - 1982
Starting with an opponent-colors formulation of color vision, two parameters, t and d, may be defined that express an illuminant's ability to realize red-green and blue-yellow contrasts of objects. For instance, calculation of t and d for daylight shows that on a gray day, color contrasts are actually reduced. By ...
Stabell U - - 1982
Chromaticities of spectral colors were measured during the cone-plateau period at 17 degrees, 25 degrees, 40 degrees and 60 degrees in the nasal field of view and at 40 degrees and 70 degrees in the temporal field. The results obtained in the nasal field show a progressive contraction of the ...
Shimomura T - - 1981
The theoretical color gamut of a nematic liquid crystal display under ambient illumination is described. The color gamut in the transmission-type of both the tunable-birefringence and guest-host modes is shown by the CIE chromaticity diagram and color solid. Calculation of the color matching between the given chromaticity coordinates and those ...
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