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Heggelund P - - 1993
The variations in the color of a test field of constant luminance during changes in the luminance of a contiguous inducing field was measured psychophysically. The fields had the same hue (red, green, or blue). The colors induced in the test field could be specified by the strength of a ...
Swanson W H WH Retina Foundation of the Southwest, Dallas, Texas - - 1993
Color matches have been used for a variety of purposes, yet the psychometric properties of color-matching data have not been thoroughly investigated. A method is given for generating psychometric functions for the two ends of the color-matching range by use of a perceptual dimension for stimulus magnitude based on ratios ...
Oliphant L W - - 1993
This paper reviews evidence for the presence of pteridines in iridophores, leucophores, and xanthophores in a wide variety of vertebrate chromatophores, and argues that the chemical and functional distinction between pterinosomes and reflecting platelets is not as clear-cut as previously believed. Observations indicate that: (1) Pteridines may, either alone or ...
Werner J S - - 1993
Mixtures of monochromatic lights that appear achromatic were measured for 50 normal, trichromatic observers ranging in age from 11 to 78 years. Stimuli were presented to one eye as a 1 degree-diameter, 1-s flash (10-s interstimulus interval) in Maxwellian view. We found the achromatic locus by varying the intensity ratio ...
Bressan P - - 1993
This paper develops the idea (Bressan, 1993) that neon spreading derives from the perceptual scissioning of ordinary assimilation color, a process identical to that occurring with nonillusory colors in phenomenal transparency. It is commonly held that the critical elements in achromatic neon spreading patterns must be of luminance intermediate between ...
Zaidi Q - - 1993
The perceived color of a region of visual space depends both on the spectral composition of the light incident from it and the light incident from surrounding regions. We studied the induced effect of combinations of colors surrounding a central test disk. Surround colors varied in a radially sinusoidal fashion ...
Antick J R - - 1993
The interaction of color wavelength and perception was evaluated during two experiments. The first study used a time-estimation task which included controls for both stimulus duration and frequency. The second study required production of duration using the same colors and three time periods to be reproduced by the participant according ...
Nagy A L - - 1993
Red-green color-discrimination thresholds were measured at eccentricities of 10 and 25 deg in the nasal retina. Thresholds were measured as a function of stimulus field size both during the cone plateau and after dark adaptation. During the cone plateau, threshold decreased with increasing field size, but the effect of field ...
Ohtani Y - - 1993
Long range apparent motion (AM) between two isolated stimuli breaks down following prolonged inspection. Time-till-breakdown (TTB) for AM between random-dot squares (red or green) on a red random-dot background was measured as a function of luminance contrast of the stimuli against the background. For the same-color (red squares on the ...
Rizzo M - - 1993
Central achromatopsia is an impairment of color perception caused by damage to the visual association cortex. Its psychophysical underpinnings remain poorly defined. We report our attempt to characterize the defect along critical dimensions of color space, taking advantage of the same standardized tasks that allow detailed profiles in patients with ...
Wehner R - - 1993
In bees and many other insects the majority of photoreceptors are twisted like a corkscrew. Here we show that this structural feature of insect eyes-whose very existence was a source of dispute for several years-is necessary for reliable encoding of information about color. Light reflected from waxy plant surfaces is ...
Zaidi Q - - 1993
Evidence is presented for a visual capacity specialized to sense the chromatic direction of change in colors over time. Discrimination thresholds were measured between pairs of suprathreshold color changes presented in consecutive intervals. In one interval, the color of a spatially uniform disk was changed at a constant speed along ...
Lucassen M P - - 1993
Color constancy was studied by the method of comparing color samples under two different illuminants using a CRT color monitor. In addition to the classical approach in which one of the illuminants is a (standard) white, we performed experiments in which the range of differential illumination was extended by using ...
Hudspeth W J - - 1993
Visual event-related potentials (VEPs) were recorded from the scalp of human observers who viewed an orthogonal stimulus set, consisting of four stimuli, each of which had two attributes: a form (circle or triangle) and a color (green or red). The stimulus set was represented by an a priori stimulus classification ...
Dengler M - - 1993
Color stereopsis refers to the effect of stimulus color on perceived depth of stimuli viewed binocularly. It is well established and well understood that the wavelength of a stimulus affects its perceived depth in color stereopsis by prismatic effects in human optics, with long-wavelength stimuli normally seen in front of ...
Korth M - - 1993
Pattern-onset electroretinograms (PERGs) with red-green color contrast (CC) and green-"black" luminance contrast (LC) stripe patterns (0.3 c/deg) were recorded in a group of 80 control subjects and in a group of 42 patients having glaucomas of varying etiology and severity. The PERG data were correlated with the results of static ...
Brown R J - - 1993
Our findings indicate that preattentive processes, such as the filling in of homogeneously colored areas, discrete dots, or bars across the blind spot, take into account both the color and the form that stimulate the retina around the optic disk. Perceptual completion of the "junction" of two opposite colors facing ...
Burns S A SA Schepens Eye Research Institute, Boston, Massachusetts - - 1993
Changes in the effective optical density of the cones are sufficient to explain changes in color matches with retinal illuminance and pupil entry. We performed three experiments. In the first experiment, six observers made color matches under both bleached and unbleached conditions to a series of six standard wavelengths. The ...
Kumar T - - 1993
It is shown that human observers can use color both for detecting and for discriminating motion. The contributions of chromaticity and luminance to the detection and discrimination of motion are investigated with a high-contrast, nonisoluminant stimulus. The motion stimulus is a rectangular 'particle' defined by its luminance and chromaticity, which ...
Watanabe T - - 1993
At the retina, each location can have only one value of luminance or color. When transparency is perceived, however, different surface qualities can be redistributed to two or more apparently superimposed layers. The experiments described here explored the characteristics of this surface decomposition. It is shown that the surface decomposition ...
Zaidi Q - - 1993
This paper concerns the processing of the outputs of the two opponent-color mechanisms in the human visual system. We present experimental evidence that opponent-color signals interact after joint modulation even though they are essentially independent under neutral steady adaptation and after exclusive modulation of each mechanism. In addition, prolonged modulation ...
Nerger J L - - 1993
A long-wavelength background can affect the appearance of an increment of light superimposed upon it in two ways. It can change the visual system's sensitivity to the increment, and it can change the appearance of the increment by directly adding redness to it. Through selective retinal-image stabilization, we evoked the ...
Dannemiller J L - - 1993
To examine the potential contribution of first-stage photoreceptor adaptation to color constancy, photon catches from 337 natural objects illuminated with phases of daylight and tungsten light were calculated for a model human fovea. The rank ordering of these photon catches within each cone photoreceptor class was examined. When first-stage adaptation ...
Capilla P - - 1993
We studied the influence of color and accommodation on the contrast sensitivity function (CSF). At the same time, we measured the effect of axial chromatic aberration (ACA) on the CSF. The CSF's of two observers were determined using red, green, blue, and white light, at 5- and 0.5-m viewing distances. ...
Neitz J - - 1993
A fundamental feature of normal color vision is that red and green lights can be mixed to appear identical with a monochromatic yellow light. Another characteristic of normal color vision is that people often disagree on the amounts of red and green needed in the mixture to exactly match the ...
Rabin J - - 1993
Certain psychophysical phenomena occur separately for color and for luminance stimulation. Separate psychophysical effects have also been elicited along different directions in equiluminant colour space. Whereas in most studies in which separate luminance and color effects have been reported the authors have used successive-adaptation approaches, less is known about the ...
Nagy A L - - 1993
Color discrimination thresholds were measured for four colors from the red-green portion of the visible spectrum. Thresholds were measured for a stimulus field 1.5 deg in diameter in the fovea and at three locations on the nasal retina (eccentricities of 5, 20 and 40 deg). Outside the fovea threshold increased ...
Shapiro A G - - 1992
The identification of three independent cardinal directions in color space suggests the existence of three independent post-receptoral mechanisms that can be desensitized by habituation to a temporally modulated light. In this paper, the differential response of each cardinal mechanism is estimated over a range of inputs before and after habituation. ...
Krauskopf J - - 1992
We have measured color discrimination in the isoluminant plane under rigorously controlled adaptation conditions. Two regimes were studied. Under the first regime the observer was adapted to the region of color space in which the discriminations were made. Thresholds for detecting changes along the S-(L + M) axis are a ...
Heggelund P - - 1992
The theory is based on a perceptive color system where the achromatic colors are specified by their degree of similarity to the three qualities white, black and luminous. Black and luminous are treated as opponent variables. It is assumed that white and luminous/black are determined by different kinds of visual ...
Kovaćs I - - 1992
Many experiments concerned with the role of color in depth and motion perception have applied isoluminant random-dot stereograms and cinematograms. The poor performance in the absence of luminance contrast has been associated with color-blindness of stereopsis and motion perception (Livingstone, M.S. & Hubel, D.H. (1987) J. Neurosci. 7, 3416-3468). Nevertheless, ...
Palacios A G - - 1992
Pigeons were trained to discriminate between spectral lights and additive mixtures in the 350-560 nm spectral range using a successive "autoshaping" discrimination procedure [introduced in Palacios, Martinoya, Bloch & Varela, Vision Research, 30, 587-596 (1990)]. Dichromatic mixtures were found in the short and near UV region, but not in the ...
Brainard D H - - 1992
We report the results of matching experiments designed to study the color appearance of objects rendered under different simulated illuminants on a CRT monitor. Subjects set asymmetric color matches between a standard object and a test object that were rendered under illuminants with different spectral power distributions. For any illuminant ...
Chaudhuri A - - 1992
The use of chromatic patterns that are equated for luminance has become increasingly popular in psychophysical and neurophysiological studies of visual processing. The currently available techniques for equating different colors for brightness rely upon human reports of perceptual events that are reduced at some luminance ratio. We report here the ...
Cameron D L - - 1992
A novel approach [referred to as the RLMS (Red Light Means Stop) approach] to automotive rear lighting has recently been suggested as a means to enhance perceptibility of the rear lights. In the RLMS approach, only red colored light is displayed during braking, and only amber colored light is displayed ...
Mukae H - - 1992
The present study was designed to investigate the effects of color temperature of lighting sources on the heart rate variability. Eight male students volunteered as subjects. The heart rate variability during task and rest sessions were estimated under nine different lighting environments consisting of three levels of color temperature (3000 ...
Dinsmoor J A - - 1992
In the first experiment, 4 pigeons were each presented with a recurring sequence of four key colors followed by the delivery of grain (block clock). Once the rate of pecking had stabilized, three of the colors were replaced, during different series of sessions, by a darkening of the key. The ...
Wesner M F - - 1992
We measured changes in the color appearance of one light caused by another light presented in a well-separated region. Observers viewed a 1 degrees test field superimposed on a 3 degrees, 540 or 660 nm adapting field (32 or 320 td). The change in appearance due to noncontiguous light was ...
Miller L K - - 1992
Researchers continue to examine the distinctiveness of motor performance by dark- versus light-eyed individuals. Dark-eyed individuals generally perform better at reactive type tasks (boxing, hitting a ball, defensive positions in football, rotary pursuit), while light-eyed individuals perform better at self-paced tasks (bowling, golf, pitching baseballs). Subjects performed two tasks, rotary ...
Meyer G J - - 1992
The Rorschach Inkblot Test was factor analyzed to assess for a two-dimensional structure that was expected to reflect the traditional interpretation of many scores, as well as two dimensions that have become a basic paradigm for studying self-reported personality and mood. In my sample (N = 268), Comprehensive System scores ...
Webster M A - - 1992
Individual differences in the color matches made by normal observers can be attributed in part to small interobserver variations in the spectral peaks (lambda max) of the cone sensitivities. I compared two different analyses of these lambda max variations that were both based on the Stiles-Burch 10 degrees color-matching functions ...
Backhaus W - - 1992
Evidence is presented that intensity dependent color shifts (Bezold-Brücke effect) occur in the color vision system of the honeybee. The evidence comes from a fit between the choices of monochromatic lights in training experiments (Menzel, R., 1981; Journal of Comparative Physiology A, 141, 389-393) and the choice percentages derived now ...
Tritsch M F - - 1992
Pattern-induced flicker colors (PIFCs) were observed and color matched in rotating discs from which higher-harmonic Fourier components in the square-wave temporal luminance functions of a conventional black-and-white Benham disc had been removed. Since both reddish-brown and blue PIFCs were visible with purely sinusoidal stimuli they cannot result from differences in ...
Bach M - - 1992
Pattern electroretinograms (PERG) and cortical visually evoked potentials (VEP) were simultaneously recorded from 7 visually normal and 1 protanopic subjects. Stimuli were color checkerboards (0.5 degrees check size), phase-reversing at 17 Hz (i.e. 34 reversals/sec). Using a stepwise sweep procedure, the luminance of the red (lambda peak = 550 nm) ...
Bensinger R - - 1992
1. Color deficiency occurs in about 8% of the population, due to alterations in the chemistry of one of the three receptive pigments for colored light, or the substitution of one pigment for another in the photoreceptor cones. 2. Subjects with pigment alteration can see a broad range of color; ...
Jitsumori M - - 1992
Pigeons were trained in a delayed matching-to-sample procedure in which the sample stimuli consisted of a compound of color (red or green) and spatial location (left or right). A postsample cue (houselight on or off) signaled whether color matching or location matching would be required following the delay. In Experiment ...
Scharff L V - - 1992
Stereo (front-back) discrimination thresholds were measured in a two-interval forced-choice paradigm for chromatic (red-green) random-dot stereograms that had all detectable longitudinal and transverse aberrations removed by low-pass filtering. The thresholds were measured as a function of the luminance ratio of the red and the green stereo elements. Although individual differences ...
Whillans M G - - 1992
At least seven million drivers in North American cannot reliably identify red and green lights. The common assumption by traffic authorities that no serious problems exist is contradicted by the data on color vision, the testimonies of color defective drivers, studies under controlled conditions, and by reliable accident statistics. Color ...
Fry G A - - 1992
The relative rates of absorption of quanta per unit of energy for the various wavelengths can be assessed for the human red, green, and blue photoreceptors by assuming that the responses generated by a photoreceptor are proportional to the rate of absorption of quanta. We start by selecting three points ...
Kwak H W - - 1992
Simple reaction time to a light target may be lengthened when the light is preceded by a noninformative stimulus at the same location. This is known as inhibition of return. Does inhibition of return result if the relation between successive stimuli is defined in terms of color or orientation? Subjects ...
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