Perceptual continuity is an important aspect of our experience of the visual world. In this study, we focus on an example of perceptual continuity involving the maintenance of figure-ground segregation despite the removal of binding cues that initiated the segregation. Fragmented line drawings of objects were superimposed on a background ...

Red-green color vision is strongly suspected to enhance the survival of its possessors. Despite being red-green color blind, however, many species have successfully competed in nature, which brings into question the evolutionary advantage of achieving red-green color vision. Here, we propose a new method of identifying positive selection at individual ...

The mode of color appearance is determined not solely by physical properties of the stimulus but also by the conditions of surrounding stimuli. Coplanar ratio hypothesis suggests that the information provided in the same plane plays an important role in the judgment of lightness. We measured the upper-limit luminances of ...

We examined the interactive contribution of the color and size of the three areas occupied by the primary colors red, yellow, and blue in adaptations of abstract compositions by Mondrian to the perceived weight of the areas and the location of the balance centers of the compositions. Thirty-six art stimuli ...

The initial evolution of aposematic and mimetic antipredator signals is thought to be paradoxical because such coloration is expected to increase the risk of predation before reaching a stage when predators associate it effectively with a defense. We propose, however, that constraints associated with the alternative strategy, cryptic coloration, may ...

In interactions, many tropical stomatopod species display conspicuous colored body spots that can communicate information about the sender's state (e.g., sex, aggressiveness, etc.). Species inhabiting a variety of depths experience large differences in illumination spectrum and intensity due to filtering of light by water and its constituents. Stomatopod spectral sensitivity ...

Glass patterns are a valuable tool to study the cortical stages of form perception. We use circular Glass patterns (cGP) to study the relation between form and color vision. The detection of Glass patterns is thought to be carried out in at least two stages. In the first stage, the ...

In order to test the human color vision objectively, we have developed the technique using the sweep parameter VEP technique (Norcia and Tyler, 1985) with an iso-luminant chromatic grating is effective to detect the defective color vision (Momose and Saito, EMBC2002). In this study, the wavelet transform using complex Morlet ...

Humans can identify the colors of objects fairly consistently, despite considerable variations in the spectral composition of the illumination. It has been suggested that the correlation between luminance and color within a scene helps to disentangle the influences of illumination and reflectance, because the surfaces that reflect the light of ...

The motion of a color-defined edge is often more difficult to perceive than the motion of a luminance-defined edge. Neurons subserving motion vision may therefore be particularly sensitive to luminance contrast. One class of neurons thought to play a critical role in motion perception is V1 neurons whose spatiotemporal receptive ...

A method to assess the discrimination capability of a camera to measure small color differences is proposed. The method helps to fix the working conditions of the camera and analyzes the reliability of the measurements through comparison with a reference instrument. Attention is paid to the camera's performance in the ...

Chromatic assimilation is the shift in color appearance of a test field toward the appearance of nearby light. Possible explanations of chromatic assimilation include wavelength independent spread light, wavelength-dependent chromatic aberration and neural summation. This study evaluated these explanations by measuring chromatic assimilation from a concentric-ring pattern into an equal-energy-white ...

The common Spanish name of the moth Rothschildia lebeau (Saturniidae) is cuatro ventanas (four 'windows'), because it exhibits a transparent oval path in each wing. The scales of the colored areas and the bristles from the "window" were analyzed. We developed a simple device to measure transmittance across the "windows" ...

Visual input is segregated in the brain into subsystems that process different attributes such as motion and color. At the same time, visual information is perceptually segregated into objects and surfaces. Here we demonstrate that perceptual segregation of visual entities based on a transparency cue precedes and affects perceptual binding ...

The maintenance of floral-color variation within natural populations is enigmatic because directional selection through pollinator preferences combined with random genetic drift should lead to the rapid loss of such variation. Fluctuating, balancing, and negative frequency-dependent selection mediated through pollinators have been identified as factors that may contribute to the maintenance ...

We examined the threshold at which a camouflaged color texture pattern (target) embedded in a surrounding colored texture pattern (background) was discriminated by making the difference between their color distributions serve as a cue. The texture consisted of 900 colored disks. The color applied to the disk was chosen from ...

We measured the color tuning of a population of S-cone-driven V1 neurons in awake, fixating monkeys. Analysis of randomly chosen color stimuli that were effective in evoking action potentials showed that these neurons received opposite sign input from the S cones and a combination of L and M cones. Surprisingly, ...

A novel full-color autostereoscopic three-dimensional (3D) display system has been developed using color-dispersion-compensated (CDC) synthetic phase holograms (SPHs) on a phase-type spatial light modulator. To design the CDC phase holograms, we used a modified iterative Fourier transform algorithm with scaling constants and phase quantization level constraints. We obtained a high ...

We report the discovery of a new class of light-sensing molecules. These light sensors are composed of fluorophore oligomers assembled on a DNA backbone. A combinatorial library of tetrafluorophores consisting of over 14 000 compounds was synthesized and screened for rapid responses toward light exposure. Among the most light-sensitive molecules, ...

Before accepting a configural or holistic account of visual perception, one should be sure that an analytic (elemental) account does not provide an equal or better explanation of the results. I suggest that when one forms a compound of a color and a line orientation with one element previously trained ...

A color-reconstruction method for electroholography is proposed in which three colored reference lights, namely, red, green, and blue light-emitting diodes, simultaneously illuminate one hologram plane. Three colored light-emitting diodes are placed at the apexes of a small right-angled triangle. Inasmuch as there is a small gap between consecutive light axes, ...

Spectral-sensitivity functions for large, long-duration increments presented on a photopic white background indicate that wavelength-opponent mechanisms mediate detection in both normal and dichromatic humans. Normal humans exhibit high color-vision sensitivity as they discriminate the color of spectral flashes at detection-threshold intensities. However, dichromatic humans require stimuli up to about 0.4 ...

Gloss is an attribute of visual appearance that originates from the geometrical distribution of the light reflected by the surface. We used the maximum likelihood difference scaling (MLDS) procedure (L.T. Maloney & J. N. Yang, 2003) to estimate gloss scales over an extended range. Observers' judgments were obtained for a ...

The color perceived to belong to the illumination of objects is often based on cues from the scene within which the objects are perceived, instead of being based on any view of the source itself. We present measurements of illuminant color estimation by human observers for moving, spectrally filtered spotlights. ...

This paper describes an automatic system for the analysis and classification of leech behavior. Three colored beads were attached to the dorsal side of a free moving or pinned leech, and color CCD camera images were taken of the animal. The leech was restrained to moving in a small tank ...

In the present study, the electrical activities of paired retinal ganglion cells, under full field light stimuli with a variety of chromatic configurations, were recorded from a small functioning piece of retina using multi-electrode array (MEA). Neurons that had increased firings at light-ON and -OFF transients and did not show ...

Precortical color vision is mediated by three independent opponent or cardinal mechanisms that linearly combine receptoral outputs to form L/M, S/(L+M), and L+M channels. However, data from a variety of psychophysical and physiological experiments indicate that chromatic processing undergoes a reorganization away from the basic opponent model. Frequently, this post-opponent ...

We examined grouping under inattention using Driver, Davis, Russell, Turatto, & Freeman's (2001) method. On each trial, two successive displays were briefly presented, each comprising a central target square surrounded by elements. The task was to judge whether the two targets were the same or different. The organization of the ...

Many animal species display striking color differences with respect to geographic location, sex, and body region. Traditional adaptive explanations for such complex patterns invoke an interaction between selection for conspicuous signals and natural selection for crypsis. Although there is now a substantial body of evidence supporting the role of sexual ...

Chimpanzees (Pan troglodytes) and rhesus macaques (Macaca mulatta) selected either Arabic numerals or colored squares on a computer monitor in a learned sequence. On shift trials, the locations of 2 stimuli were interchanged at some point. More errors were made when this interchange occurred for the next 2 stimuli to ...

The human visual system undergoes continuous anatomical, physiological and functional changes throughout the life span. There is also continuous change in the spectral distribution and intensity of light reaching the retina from infancy through senescence, primarily due to changes in the absorption of short-wave light by the lens. Despite these ...

Poison frogs in the anuran family Dendrobatidae use bright colors on their bodies to advertise toxicity. The species Dendrobates pumilio Schmidt 1858, the strawberry poison frog, shows extreme polymorphism in color and pattern in Panama. It is known that females of D. pumilio preferentially choose mates of their own color ...

Patterns of geographic variation in phenotype or genotype may provide evidence for natural selection. Here, we compare phenotypic variation in color, allele frequencies of a pigmentation gene (the melanocortin-1 receptor, Mc1r), and patterns of neutral mitochondrial DNA (mtDNA) variation in rock pocket mice (Chaetodipus intermedius) across a habitat gradient in ...

Rapid automatic naming tasks are clinical tools for probing brain functions that underlie normal cognition. To compare performance for various stimuli in normal subjects and assess the effect of aging, we administered six single-dimension stimuli (color, form, number, letter, animal, and object) and five dual-dimension stimuli (color-form, color-number, color-letter, color-animal, ...

There is enormous variation in the X-linked L/M (long/middle wavelength sensitive) gene array underlying "normal" color vision in humans. This variability has been shown to underlie individual variation in color matching behavior. Recently, red-green color blindness has also been shown to be associated with distinctly different genotypes. This has opened ...

Many problems regarding color opponency are still unsolved. In this study the system of the uniform color scales of the Optical Society of America (OSA-UCS) is analyzed with the aim of obtaining answers to very general questions on color opponency. The perceptual color opponencies in the OSA-UCS system, represented by ...

The spectral properties of chromatic-detection mechanisms were investigated using a noise-masking paradigm. Contrast-detection thresholds were measured for a signal with a Gaussian spatial profile, modulated in the equiluminant plane in the presence of spatial chromatic noise. The noise was distributed within a sector in the equiluminant plane, centered on the ...

We have studied the influence of chromatic adaptation upon the perceived visual position of a test stimulus using a Vernier alignment task. Maximum and minimum offsets in spatial position are generated when the adapting and test stimuli lie on the same and orthogonal axes in MBDKL color space, respectively. When ...

Previous work (Nagy & Thomas, 2003) showed that signals in different Cardinal color mechanisms could be combined to facilitate search for a color target. Further investigation (Nagy et al., 2003) suggested that signals in one Cardinal color mechanism were used to select a subset of stimuli to be attended, while ...

The optical density of the human crystalline lens progressively increases with age, the greatest increase in the visible spectrum being at short wavelengths. This produces a gradual shift in the spectral distribution of the light reaching the retina, yet color appearance remains relatively stable across the life span, implying that ...

We used color contrast adaptation to examine the chromatic and contrast selectivity of central color mechanisms. Adaptation to a field whose color varies along a single axis of color space induces a selective loss in sensitivity to the adapting axis. The resulting changes in color appearance are consistent with mechanisms ...

The ability of color-deficient observers to discriminate between illuminant changes and surface-reflectance changes in a scene was tested with natural and Munsell reflectance spectra. To avoid the confounding effects of spatial structure, stimuli were simulations of Mondrian-like colored patterns, presented on a computer-controlled color monitor. Protanopes performed less well than ...

A new visual phenomenon that we call flashing anomalous color contrast is described. This phenomenon arises from the interaction between a gray central disk and a chromatic annulus surrounded by black radial lines. In an array of such figures, the central gray disk no longer appears gray, but assumes a ...

Relational color constancy refers to the constancy of the perceived relations between the colors of surfaces of a scene under changes in the spectral composition of the illuminant. Spatial ratios of cone excitations provide a natural physical basis for this constancy, as, on average, they are almost invariant under illuminant ...

If surfaces in a scene are to be distinguished by their color, their neural representation at some level should ideally vary little with the color of the illumination. Four possible neural codes were considered: von-Kries-scaled cone responses from single points in a scene, spatial ratios of cone responses produced by ...

STATEMENT OF PROBLEM: External prostheses composed of silicone elastomers exhibit an unwanted color change over time. PURPOSE: This study evaluated color stability when an ultraviolet light absorber and hindered amine light stabilizer were mixed in the maxillofacial elastomer containing either organic or inorganic pigments. MATERIAL AND METHODS: The materials used ...

For normal trichromats, the hue of a light can change as its luminance varies. This Bezold-Brücke (B-B) hue shift is commonly attributed to nonlinearity in the blue-yellow opponent system. In the present study, we questioned whether protanopes experience analogous changes. Two protanopes (Ps) viewed spectral lights at six luminance levels ...

Chromatic induction from patterned backgrounds depends on the spatial as well as the chromatic aspects of the background light. Color appearance with patterned and uniform backgrounds was compared using chromaticities distinguished by only the S cones; all backgrounds were equivalent to equal-energy white in terms of L-cone and M-cone stimulation. ...

Many previous studies have shown that background color affects the discriminability and appearance of color stimuli. However, research on visual search has not typically considered the role that the background may play. Rosenholtz (2001a) has suggested that color search asymmetries result from the relationship between the stimuli and the background. ...

The inability of the human visual system to fuse dissimilar patterns in corresponding regions of the two eyes results in stochastic alternation of perceptual dominance between the two patterns: rivalry. When rivalrous stimuli are presented intermittently their perception is stabilized (Leopold, Wilke, Maier, & Logothetis, 2002). This stability indicates the ...