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Sample records for colour vision impairment

  1. Colour Vision Impairment in Young Alcohol Consumers

    PubMed Central

    Brasil, Alódia; Castro, Antônio José O.; Martins, Isabelle Christine V. S.; Lacerda, Eliza Maria C. B.; Souza, Givago S.; Herculano, Anderson Manoel; Rosa, Alexandre Antônio M.; Rodrigues, Anderson R.; Silveira, Luiz Carlos L.

    2015-01-01

    Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns. Twenty-four young adults were evaluated by an ophthalmologist and performed three psychophysical tests to evaluate their vision functions. We estimated the spatial luminance contrast sensitivity function at 11 spatial frequencies ranging from 0.1 to 30 cycles/degree. No difference in contrast sensitivity was observed comparing alcohol consumers and control subjects. For the evaluation of colour vision, we used the Farnsworth-Munsell 100 hue test (FM 100 test) to test subject’s ability to perform a colour arrangement task and the Mollon-Reffin test (MR test) to measure subject’s colour discrimination thresholds. Alcohol consumers made more mistakes than controls in the FM100 test, and their mistakes were diffusely distributed in the FM colour space without any colour axis preference. Alcohol consumers also performed worse than controls in the MR test and had higher colour discrimination thresholds compared to controls around three different reference points of a perceptually homogeneous colour space, the CIE 1976 chromaticity diagram. There was no colour axis preference in the threshold elevation observed among alcoholic subjects. Young adult weekly alcohol consumers showed subclinical colour vision losses with preservation of spatial luminance contrast sensitivity. Adolescence and young adult age are periods of important neurological development and alcohol exposure during this period of life might be responsible for deficits in visual functions, especially colour vision that is very sensitive to neurotoxicants. PMID:26465148

  2. Unconventional colour vision.

    PubMed

    Marshall, Justin; Arikawa, Kentaro

    2014-12-15

    Butterflies and stomatopods are certainly outliers in their unconventional colour sense and despite some similarities at first glance, in fact sample the world of colour very differently. In one way, butterflies are relatively conventional, possessing either tri-or tetrachromatic colour vision, then just adding one or several task-specific sub-mechanisms onto this. It is the stomatopods so far that have really pushed the boat out into a different colour vision mechanism. Over 400 million years of independent evolution they have arrived at a solution with more in common with the way a satellite sensor examines the colours of the earth than other animals. Remember, however, that unconventional colour vision is not just the realm of the serially polychromatic. Apparently waterfleas with four classes of spectral receptors living in ponds operate a task-specific spectral sense with no need, or indeed neural processing power, to construct a complex discriminatory mechanism. It seems they have the butterfly added-extra set without the more complex comparative chromatic mechanisms, although in truth, conclusive behavioural proof is lacking. Behavioural observation of colour vision in the ecological context of each animal is vital before making the distinction between conventional and unconventional. Just counting spectral sensitivities is never enough. PMID:25514002

  3. Colour vision in marine organisms.

    PubMed

    Marshall, Justin; Carleton, Karen L; Cronin, Thomas

    2015-10-01

    Colour vision in the marine environment is on average simpler than in terrestrial environments with simple or no colour vision through monochromacy or dichromacy. Monochromacy is found in marine mammals and elasmobranchs, including whales and sharks, but not some rays. Conversely, there is also a greater diversity of colour vision in the ocean than on land, examples being the polyspectral stomatopods and the many colour vision solutions found among reef fish. Recent advances in sequencing reveal more opsin (visual pigment) types than functionally useful at any one time. This diversity arises through opsin duplication and conversion. Such mechanisms allow pick-and-mix adaptation that tunes colour vision on a variety of very short non-evolutionary timescales. At least some of the diversity in marine colour vision is best explained as unconventional colour vision or as neutral drift. PMID:25725325

  4. All Vision Impairment

    MedlinePLUS

    ... Research at NEI Education Programs Training and Jobs All Vision Impairment Listen Vision Impairment Defined Vision impairment ... being blind by the U.S. definition.) The category “All Vision Impairment” includes both low vision and blindness. ...

  5. A Colour Vision Experiment.

    ERIC Educational Resources Information Center

    Lovett, David; Hore, Kevin

    1991-01-01

    The model for color vision put forward by Edwin Land is explained. The aspects of the theory that can be demonstrated within the classroom are described. A random arrangement of straight-edged colored areas mounted on a screen, called a Mondrian, projectors, and a computer are used to calculate reflectance. (KR)

  6. Impairment of Colour Vision in Diabetes with No Retinopathy: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetics Study (SNDREAMS- II, Report 3)

    PubMed Central

    Gella, Laxmi; Raman, Rajiv; Kulothungan, Vaitheeswaran; Pal, Swakshyar Saumya; Ganesan, Suganeswari; Sharma, Tarun

    2015-01-01

    Purpose To assess impairment of colour vision in type 2 diabetics with no diabetic retinopathy and elucidate associated risk factors in a population-based cross-sectional study. Methods This is part of Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular-genetics Study (SN-DREAMS II) which was conducted between 2007–2010. FM 100 hue-test was performed in 253 subjects with no clinical evidence of diabetic retinopathy. All subjects underwent detailed ophthalmic evaluation including cataract grading using LOCS III and 45° 4-field stereoscopic fundus photography. Various ocular and systemic risk factors for impairment of colour vision (ICV) were assessed in subjects with diabetes but no retinopathy. P value of < 0.05 was considered statistically significant. Results The mean age of the study sample was 57.08 ± 9.21 (range: 44–86 years). Gender adjusted prevalence of ICV among subjects with diabetes with no retinopathy was 39.5% (CI: 33.5–45.5). The mean total error score in the study sample was 197.77 ± 100 (range: 19–583). The risk factors for ICV in the study were women OR: 1.79 (1.00–3.18), increased resting heart rate OR: 1.04 (1.01–1.07) and increased intraocular pressure OR: 1.12 (1.00–1.24). Significant protective factor was serum high-density lipoprotein OR: 0.96 (0.93–0.99). Conclusions Acquired ICV is an early indicator of neurodegenerative changes in the retina. ICV found in diabetic subjects without retinopathy may be of non-vascular etiology. PMID:26053017

  7. Evolution of colour vision in mammals

    PubMed Central

    Jacobs, Gerald H.

    2009-01-01

    Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The basic biological mechanisms on which vertebrate colour vision ultimately rests, the cone opsin genes and the photopigments they specify, are highly conserved. Within that constraint, however, the utilization of these basic elements varies in striking ways in that they appear, disappear and emerge in altered form during the course of evolution. These changes, along with other alterations in the visual system, have led to profound variations in the nature and salience of colour vision among the vertebrates. This article concerns the evolution of colour vision among the mammals, viewing that process in the context of relevant biological mechanisms, of variations in mammalian colour vision, and of the utility of colour vision. PMID:19720656

  8. Kids' Quest: Vision Impairment

    MedlinePLUS

    ... important job. Â Return to Steps World-Wide Web Search Kids Health: What is Vision Impairment What ... for the Blind (AFB) created the Braille Bug web site to teach sighted children about braille, and ...

  9. Molecular genetics of colour vision deficiencies.

    PubMed

    Deeb, Samir S

    2004-07-01

    Common variation in colour vision exists among both colour normal and colour deficient subjects. Differences at a few amino acid positions that influence the spectra of the L and M cone pigments account for most of this variation. The genes encoding the L and M photopigments are arranged in head-to-tail arrays on the X-chromosome, beginning with the L and followed by one or more M pigment genes. The L and M pigment genes are highly homologous, which predisposed them to unequal crossing over (recombination) resulting in gene deletions and in formation of L/M hybrid genes that encode a variety of pigments with either L-like or M-like spectra that account for the majority of colour vision defects. Only the first two pigment genes of the L/M array are expressed in the retina and, therefore, need to be considered in predicting colour vision. A common single amino acid polymorphism (serine or alanine) at position 180 of the L-pigment plays an important role both in variation in normal colour vision and in the severity of colour vision defects. Blue cone monochromacy is a rare form of colour vision deficiency that results from mutations that abolish function of both the L and M pigment genes. All the above defects are inherited as X-linked recessive traits. Tritanopia is also a rare autosomal dominant colour vision defect caused by mutations in the S pigment gene located on chromosome 7. Total colour blindness (achromatopsia or rod monochromacy) is a rare autosomal recessive trait caused by mutations in genes encoding the proteins of the photoreceptor cation channel or cone transducin that are essential for function of all classes of cone. PMID:15312026

  10. Ecology and evolution of primate colour vision.

    PubMed

    Vorobyev, Misha

    2004-07-01

    More than one hundred years ago, Grant Allen suggested that colour vision in primates, birds and insects evolved as an adaptation for foraging on colourful advertisements of plants--fruits and flowers. Recent studies have shown that well developed colour vision appeared long before fruits and flowers evolved. Thus, colour vision is generally beneficial for many animals, not only for those eating colourful food. Primates are the only placental mammals that have trichromatic colour vision. This may indicate either that trichromacy is particularly useful for primates or that primates are unique among placental mammals in their ability to utilise the signals of three spectrally distinct types of cones or both. Because fruits are an important component of the primate diet, primate trichromacy could have evolved as a specific adaptation for foraging on fruits. Alternatively, primate trichromacy could have evolved as an adaptation for many visual tasks. Comparative studies of mammalian eyes indicate that primates are the only placental mammals that have in their retina a pre-existing neural machinery capable of utilising the signals of an additional spectral type of cone. Thus, the failure of non-primate placental mammals to evolve trichromacy can be explained by constraints imposed on the wiring of retinal neurones. PMID:15312027

  11. The Physics of Colour Vision.

    ERIC Educational Resources Information Center

    Goldman, Martin

    1985-01-01

    An elementary physical model of cone receptor cells is explained and applied to complexities of human color vision. One-, two-, and three-receptor systems are considered, with the later shown to be the best model for the human eye. Color blindness is also discussed. (DH)

  12. Vision Impairment and Blindness

    MedlinePLUS

    ... aids such as special glasses and large print books can make life easier. There are also devices ... no vision, like text-reading software and braille books. The sooner vision loss or eye disease is ...

  13. Animal colour vision--behavioural tests and physiological concepts.

    PubMed

    Kelber, Almut; Vorobyev, Misha; Osorio, Daniel

    2003-02-01

    Over a century ago workers such as J. Lubbock and K. von Frisch developed behavioural criteria for establishing that non-human animals see colour. Many animals in most phyla have since then been shown to have colour vision. Colour is used for specific behaviours, such as phototaxis and object recognition, while other behaviours such as motion detection are colour blind. Having established the existence of colour vision, research focussed on the question of how many spectral types of photoreceptors are involved. Recently, data on photoreceptor spectral sensitivities have been combined with behavioural experiments and physiological models to study systematically the next logical question: 'what neural interactions underlie colour vision?' This review gives an overview of the methods used to study animal colour vision, and discusses how quantitative modelling can suggest how photoreceptor signals are combined and compared to allow for the discrimination of biologically relevant stimuli. PMID:12620062

  14. From spectral information to animal colour vision: experiments and concepts

    PubMed Central

    Kelber, Almut; Osorio, Daniel

    2010-01-01

    Many animals use the spectral distribution of light to guide behaviour, but whether they have colour vision has been debated for over a century. Our strong subjective experience of colour and the fact that human vision is the paradigm for colour science inevitably raises the question of how we compare with other species. This article outlines four grades of colour vision that can be related to the behavioural uses of spectral information, and perhaps to the underlying mechanisms. In the first, even without an (image-forming) eye, simple organisms can compare photoreceptor signals to locate a desired light environment. At the next grade, chromatic mechanisms along with spatial vision guide innate preferences for objects such as food or mates; this is sometimes described as wavelength-specific behaviour. Here, we compare the capabilities of di- and trichromatic vision, and ask why some animals have more than three spectral types of receptors. Behaviours guided by innate preferences are then distinguished from a grade that allows learning, in part because the ability to learn an arbitrary colour is evidence for a neural representation of colour. The fourth grade concerns colour appearance rather than colour difference: for instance, the distinction between hue and saturation, and colour categorization. These higher-level phenomena are essential to human colour perception but poorly known in animals, and we suggest how they can be studied. Finally, we observe that awareness of colour and colour qualia cannot be easily tested in animals. PMID:20164101

  15. Colour vision of the foraging swallowtail butterfly papilio xuthus

    PubMed

    Kinoshita; Shimada; Arikawa

    1999-01-01

    This paper demonstrates that foraging summer-form females of the Japanese yellow swallowtail butterfly Papilio xuthus have colour vision. The butterflies were trained to feed on sucrose solution placed on a disk of a particular colour in a cage set in the laboratory. After a few such training runs, a butterfly was presented with the training colour randomly positioned within an array of disks of other colours, but with no sucrose solution. The results indicate that the butterflies learn rapidly to select the training colour reliably among different colours. The training colour was also correctly selected when it was covered with neutral density filters to reduce its brightness, or even when the colour was presented together with disks of a variety of shades of grey. These results demonstrate convincingly, for the first time, that a butterfly has true colour vision. PMID:9851899

  16. Behavioural evidence for colour vision in an elasmobranch.

    PubMed

    Van-Eyk, Sarah M; Siebeck, Ulrike E; Champ, Connor M; Marshall, Justin; Hart, Nathan S

    2011-12-15

    Little is known about the sensory abilities of elasmobranchs (sharks, skates and rays) compared with other fishes. Despite their role as apex predators in most marine and some freshwater habitats, interspecific variations in visual function are especially poorly studied. Of particular interest is whether they possess colour vision and, if so, the role(s) that colour may play in elasmobranch visual ecology. The recent discovery of three spectrally distinct cone types in three different species of ray suggests that at least some elasmobranchs have the potential for functional trichromatic colour vision. However, in order to confirm that these species possess colour vision, behavioural experiments are required. Here, we present evidence for the presence of colour vision in the giant shovelnose ray (Glaucostegus typus) through the use of a series of behavioural experiments based on visual discrimination tasks. Our results show that these rays are capable of discriminating coloured reward stimuli from other coloured (unrewarded) distracter stimuli of variable brightness with a success rate significantly different from chance. This study represents the first behavioural evidence for colour vision in any elasmobranch, using a paradigm that incorporates extensive controls for relative stimulus brightness. The ability to discriminate colours may have a strong selective advantage for animals living in an aquatic ecosystem, such as rays, as a means of filtering out surface-wave-induced flicker. PMID:22116761

  17. The absolute threshold of colour vision in the horse.

    PubMed

    Roth, Lina S V; Balkenius, Anna; Kelber, Almut

    2008-01-01

    Arrhythmic mammals are active both during day and night if they are allowed. The arrhythmic horses are in possession of one of the largest terrestrial animal eyes and the purpose of this study is to reveal whether their eye is sensitive enough to see colours at night. During the day horses are known to have dichromatic colour vision. To disclose whether they can discriminate colours in dim light a behavioural dual choice experiment was performed. We started the training and testing at daylight intensities and the horses continued to choose correctly at a high frequency down to light intensities corresponding to moonlight. One Shetland pony mare, was able to discriminate colours at 0.08 cd/m(2), while a half blood gelding, still discriminated colours at 0.02 cd/m(2). For comparison, the colour vision limit for several human subjects tested in the very same experiment was also 0.02 cd/m(2). Hence, the threshold of colour vision for the horse that performed best was similar to that of the humans. The behavioural results are in line with calculations of the sensitivity of cone vision where the horse eye and human eye again are similar. The advantage of the large eye of the horse lies not in colour vision at night, but probably instead in achromatic tasks where presumably signal summation enhances sensitivity. PMID:19002261

  18. The Absolute Threshold of Colour Vision in the Horse

    PubMed Central

    Roth, Lina S. V.; Balkenius, Anna; Kelber, Almut

    2008-01-01

    Arrhythmic mammals are active both during day and night if they are allowed. The arrhythmic horses are in possession of one of the largest terrestrial animal eyes and the purpose of this study is to reveal whether their eye is sensitive enough to see colours at night. During the day horses are known to have dichromatic colour vision. To disclose whether they can discriminate colours in dim light a behavioural dual choice experiment was performed. We started the training and testing at daylight intensities and the horses continued to choose correctly at a high frequency down to light intensities corresponding to moonlight. One Shetland pony mare, was able to discriminate colours at 0.08 cd/m2, while a half blood gelding, still discriminated colours at 0.02 cd/m2. For comparison, the colour vision limit for several human subjects tested in the very same experiment was also 0.02 cd/m2. Hence, the threshold of colour vision for the horse that performed best was similar to that of the humans. The behavioural results are in line with calculations of the sensitivity of cone vision where the horse eye and human eye again are similar. The advantage of the large eye of the horse lies not in colour vision at night, but probably instead in achromatic tasks where presumably signal summation enhances sensitivity. PMID:19002261

  19. Parallel inputs to memory in bee colour vision.

    PubMed

    Horridge, Adrian

    2016-03-01

    In the 19(th) century, it was found that attraction of bees to light was controlled by light intensity irrespective of colour, and a few critical entomologists inferred that vision of bees foraging on flowers was unlike human colour vision. Therefore, quite justly, Professor Carl von Hess concluded in his book on the Comparative Physiology of Vision (1912) that bees do not distinguish colours in the way that humans enjoy. Immediately, Karl von Frisch, an assistant in the Zoology Department of the same University of Münich, set to work to show that indeed bees have colour vision like humans, thereby initiating a new research tradition, and setting off a decade of controversy that ended only at the death of Hess in 1923. Until 1939, several researchers continued the tradition of trying to untangle the mechanism of bee vision by repeatedly testing trained bees, but made little progress, partly because von Frisch and his legacy dominated the scene. The theory of trichromatic colour vision further developed after three types of receptors sensitive to green, blue, and ultraviolet (UV), were demonstrated in 1964 in the bee. Then, until the end of the century, all data was interpreted in terms of trichromatic colour space. Anomalies were nothing new, but eventually after 1996 they led to the discovery that bees have a previously unknown type of colour vision based on a monochromatic measure and distribution of blue and measures of modulation in green and blue receptor pathways. Meanwhile, in the 20(th) century, search for a suitable rationalization, and explorations of sterile culs-de-sac had filled the literature of bee colour vision, but were based on the wrong theory. PMID:26960353

  20. [Inherited colour vision deficiencies--from Dalton to molecular genetics].

    PubMed

    Cvetkovi?, Dragana; Cvetkovi?, Dobrosav

    2005-01-01

    In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton's real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or "blue" gene) and X (the L or "red" gene and the M or "green" gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes--a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin. PMID:16758855

  1. Bird colour vision: behavioural thresholds reveal receptor noise.

    PubMed

    Olsson, Peter; Lind, Olle; Kelber, Almut

    2015-01-15

    Birds have impressive physiological adaptations for colour vision, including tetrachromacy and coloured oil droplets, yet it is not clear exactly how well birds can discriminate the reflecting object colours that they encounter in nature. With behavioural experiments, we determined colour discrimination thresholds of chickens in bright and dim light. We performed the experiments with two colour series, orange and green, covering two parts of chicken colour space. These experiments allowed us to compare behavioural results with model expectations and determine how different noise types limit colour discrimination. At intensities ranging from bright light to those corresponding to early dusk (250-10 cd m(-2)), we describe thresholds accurately by assuming a constant signal-to-noise ratio, in agreement with an invariant Weber fraction of Weber's law. Below this intensity, signal-to-noise ratio decreases and Weber's law is violated because photon-shot noise limits colour discrimination. In very dim light (below 0.05 cd m(-2) for the orange series or 0.2 cd m(-2) for the green series) colour discrimination is possibly constrained by dark noise, and the lowest intensity at which chickens can discriminate colours is 0.025 and 0.08 cd m(-2) for the orange and green series, respectively. Our results suggest that chickens use spatial pooling of cone outputs to mitigate photon-shot noise. Surprisingly, we found no difference between colour discrimination of chickens and humans tested with the same test in bright light. PMID:25609782

  2. Dark Adaptation of Colour Vision in Diabetic Subjects

    NASA Astrophysics Data System (ADS)

    Márquez-Gamiño, S.; Cortés-Peñaloza, J. L.; Pérez-Hernández, J. U.; Cruz-Rodríguez, E.; Caudillo, C.

    2004-09-01

    Eye disease, a late complication of diabetes mellitus (DM) occurs even under a careful glicemic control. It includes optic nerve, retina, vitreous humor, crystalline lens and pupillary affection. The physiopathological process could be independent of blood glucose levels or start at initial stages of the disease. Photoreceptors have specific physiological functions. The functional substrate of day light or colour vision in superior primates, the cones have different spectral sensitivity, 455, 530 and 560 nm. The rods, maximal sensitivity at 505 nm, are much more sensitive to light than are cones. Dark adaptation was tested to evaluate functional impairment differences in photoreceptors of diabetic subjects. 14 DM2 (type 2 DM), and 5 DM1 (type 1 DM) patients, as well as 9 healthy subjects were studied. Retinal affected individuals, were excluded. Dark adaptation curves seemed to be different between DM, and healthy subjects. Cones, specially those sensitive to 560 nm type, seems to be more labile to DM, as demonstrated by the lack of sensitivity to low, and medium intensity stimuli. Medical Physics and elementary Biomedical Engineering exhibited to be useful to discern malfunction between different types of photorreceptors. The inexpensive method used could be applied for early color vision alteration detection.

  3. Homing in Pigeons with Impaired Vision

    PubMed Central

    Schmidt-Koenig, K.; Schlichte, H. J.

    1972-01-01

    In order to test the importance of vision in homing pigeons, their vision was impaired by frosted contact lenses. Pigeons wearing such lenses seemed unable to recognize artificial landmarks at 6-m distance. Nevertheless, most birds homed from distances of 15 km, and some even from 130-km distance. This result indicates that, contrary to common expectation, vision need not play an essential role in homing. PMID:4506767

  4. Colour vision and response bias in a coral reef fish.

    PubMed

    Cheney, Karen L; Newport, Cait; McClure, Eva C; Marshall, N Justin

    2013-08-01

    Animals use coloured signals for a variety of communication purposes, including to attract potential mates, recognize individuals, defend territories and warn predators of secondary defences (aposematism). To understand the mechanisms that drive the evolution and design of such visual signals, it is important to understand the visual systems and potential response biases of signal receivers. Here, we provide raw data on the spectral capabilities of a coral reef fish, the Picasso triggerfish Rhinecanthus aculeatus, which is potentially trichromatic with three cone sensitivities of 413 nm (single cone), 480 nm (double cone, medium sensitivity) and 528 nm (double cone, long sensitivity), and a rod sensitivity of 498 nm. The ocular media have a 50% transmission cut off at 405 nm. Behavioural experiments confirmed colour vision over their spectral range; triggerfish were significantly more likely to choose coloured stimuli over grey distractors, irrespective of luminance. We then examined whether response biases existed towards coloured and patterned stimuli to provide insight into how visual signals - in particular, aposematic colouration - may evolve. Triggerfish showed a preferential foraging response bias to red and green stimuli, in contrast to blue and yellow, irrespective of pattern. There was no response bias to patterned over monochromatic non-patterned stimuli. A foraging response bias towards red in fish differs from that of avian predators, who often avoid red food items. Red is frequently associated with warning colouration in terrestrial environments (ladybirds, snakes, frogs), whilst blue is used in aquatic environments (blue-ringed octopus, nudibranchs); whether the design of warning (aposematic) displays is a cause or consequence of response biases is unclear. PMID:23580729

  5. Colour change in cyanosis and the confusions of congenital colour vision deficient observers.

    PubMed

    McNamara, Renae; Taylor, Clair M; McKenzie, David K; Coroneo, Minas T; Dain, Stephen J

    2010-09-01

    Visual recognition of cyanosis is an important clinical activity. While pulse oximetry is almost universal in the hospital environment, there are circumstances where it is not available or may be unreliable. Cyanosis recognition is affected by lighting colour. In addition, there is, mainly anecdotal, evidence that people with greater colour vision deficiencies (CVDs) have particular difficulty and there is no effective lighting strategy to assist in the observation. The change of blood colour with oxygenation has been shown to lie close to the direction of colour confusions made by congenital red-green dichromats. The important sites of observation are lips, nail beds and palm creases. 10 subjects who were known to be chronically hypoxaemic were recruited from the chronic respiratory program. Their blood oxygen saturation (SpO(2)) varied from 84% to 96% pre-exercise, and 61-84% post-exercise. Ten normal subjects were recruited whose SpO(2) was 99% or 100%. The spectral radiances of lips, nail beds and palm creases were measured using a telespectroradiometer and compared with the spectral radiances of a white tile of known spectral reflectances measured in the same location. This is a non-contact method of measurement, avoiding the blanching caused by pressure of contact methods. The spectral reflectances were calculated, and the chromaticities calculated for a Planckian radiator T = 4000K. Measurements on lips yielded the most consistent results. The colour changes pre- and post-exercise and compared with normal colour lie generally along a deutan confusion line. These results show the direction of the colour change and confirm the, previously anecdotal, difficulties in detecting cyanosis by observers with CVDs. PMID:20883357

  6. Orientation tuning in human colour vision at detection threshold.

    PubMed

    Gheiratmand, Mina; Mullen, Kathy T

    2014-01-01

    We measure the orientation tuning of red-green colour and luminance vision at low (0.375?c/deg) and mid (1.5?c/deg) spatial frequencies using the low-contrast psychophysical method of subthreshold summation. Orientation bandwidths of the underlying neural detectors are found using a model involving Minkowski summation of the rectified outputs of a bank of oriented filters. At 1.5?c/deg, we find orientation-tuned detectors with similar bandwidths for chromatic and achromatic contrast. At 0.375?c/deg, orientation tuning is preserved with no change in bandwidth for achromatic stimuli, however, for chromatic stimuli orientation tuning becomes extremely broad, compatible with detection by non-oriented colour detectors. A non-oriented colour detector, previously reported in single cells in primate V1 but not psychophysically in humans, can transmit crucial information about the color of larger areas or surfaces whereas orientation-tuned detectors are required to detect the colour or luminance edges that delineate an object's shape. PMID:24594749

  7. L-cone pigment genes expressed in normal colour vision.

    PubMed

    Sjoberg, S A; Neitz, M; Balding, S D; Neitz, J

    1998-11-01

    To directly test the hypothesis that only two pigment genes are expressed from the X-chromosome array, we examined expressed M and L pigment gene sequences from > 100 male eye donors. In this sample, there were eight men who expressed high levels of more than one L pigment gene in addition to M pigment genes. The fact that these eyes expressed both L and M pigment genes at significant levels suggests they were from men with normal colour vision. We reject the hypothesis that only two pigment genes from one X-chromosome array can be expressed. PMID:9893828

  8. Stochastic spineless expression creates the retinal mosaic for colour vision

    PubMed Central

    Duncan, Dianne M.; Duncan, Ian; Desplan, Claude

    2013-01-01

    Drosophila colour vision is achieved by R7 and R8 photoreceptor cells present in every ommatidium. The fly retina contains two types of ommatidia, called pale and yellow, defined by different rhodopsin pairs expressed in R7 and R8 cells. Similar to the human cone photoreceptors, these ommatidial subtypes are distributed stochastically in the retina. The choice between pale versus yellow ommatidia is made in R7 cells, which then impose their fate onto R8. Here we report that the Drosophila dioxin receptor Spineless is both necessary and sufficient for the formation of the ommatidial mosaic. A short burst of spineless expression at mid-pupation in a large subset of R7 cells precedes rhodopsin expression. In spineless mutants, all R7 and most R8 cells adopt the pale fate, whereas overexpression of spineless is sufficient to induce the yellow R7 fate. Therefore, this study suggests that the entire retinal mosaic required for colour vision is defined by the stochastic expression of a single transcription factor, Spineless. PMID:16525464

  9. Psychological Adjustment in Adolescents with Vision Impairment

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2012-01-01

    The present study compared psychological adjustment of 158 adolescents with vision impairment and 158 sighted adolescents with a matched-pair design using the Strengths and Difficulties Questionnaire. Adolescent self-reports and teacher reports on emotional problems, peer problems, and total difficulties showed higher scores in students with

  10. Low Vision Aids for Visually Impaired Children

    ERIC Educational Resources Information Center

    Schurink, J.; Cox, R. F. A.; Cillessen, A. H. N.; van Rens, G. H. M. B.; Boonstra, F. N.

    2011-01-01

    It is a widely accepted belief in clinical practice that children with a visual impairment can profit from the use of a low vision aid (LVA). However, we found a considerable gap in our scientific understanding of LVA use, particularly in young children. This is the reason for the analysis presented in this paper. A selected overview of LVA use in

  11. Low Vision Aids for Visually Impaired Children

    ERIC Educational Resources Information Center

    Schurink, J.; Cox, R. F. A.; Cillessen, A. H. N.; van Rens, G. H. M. B.; Boonstra, F. N.

    2011-01-01

    It is a widely accepted belief in clinical practice that children with a visual impairment can profit from the use of a low vision aid (LVA). However, we found a considerable gap in our scientific understanding of LVA use, particularly in young children. This is the reason for the analysis presented in this paper. A selected overview of LVA use in…

  12. Is screening for congenital colour vision deficiency in school students worthwhile? A review.

    PubMed

    Ramachandran, Nishanthan; Wilson, Graham A; Wilson, Nick

    2014-11-01

    This review analyses the literature on screening for congenital colour vision deficiency in school students, which predominantly uses the Ishihara test. The review was framed with respect to the established Wilson and Jungner criteria for screening programs. These criteria relate to the characteristics of the condition concerned, the performance of the screening test, the existence of treatment options and the performance of screening programs. The literature reviewed suggests that congenital colour vision deficiency has not been shown to increase risk of road traffic crashes and is not a preclusion to driver licensing in most developed countries. The occurrence of congenital colour vision deficiency has been used to limit entry into certain occupations; however, the value of screening school students with regard to occupational preclusion is questionable. Stronger evidence exists indicating no association between congenital colour vision deficiency and level of educational achievement. Studies showing any association between congenital colour vision deficiency and other health and lifestyle impacts were rare. The most commonly used screening test (using Ishihara pseudoisochromatic plates) performs well with respect to detecting red-green colour vision deficiencies. Finally, the only interventions we identified for congenital colour vision deficiency were management ones around the availability of specific tinted lenses and computer programs to aid colour perception in certain tasks. Given this picture, the weight of evidence appears to be in favour of not adopting (or discontinuing) routine colour vision screening programs for school students; however, it may be worthwhile for a career advisor to refer school students to an optometrist or ophthalmologist for colour vision screening, upon expression of interest in an occupation where normal colour vision is either particularly desirable or is a regulatory requirement. PMID:25039829

  13. Suitability of School Textbooks for 5 to 7 Year Old Children with Colour Vision Deficiencies

    ERIC Educational Resources Information Center

    Torrents, Aurora; Bofill, Francesc; Cardona, Genis

    2011-01-01

    Purpose: The aim of the present study was to determine, through colorimetric analysis, whether school textbooks for children aged 5 to 7 years contained tasks requiring normal colour vision discrimination for their resolution. In addition, the performance of a group of observers with diverse colour vision deficiencies was evaluated while

  14. Suitability of School Textbooks for 5 to 7 Year Old Children with Colour Vision Deficiencies

    ERIC Educational Resources Information Center

    Torrents, Aurora; Bofill, Francesc; Cardona, Genis

    2011-01-01

    Purpose: The aim of the present study was to determine, through colorimetric analysis, whether school textbooks for children aged 5 to 7 years contained tasks requiring normal colour vision discrimination for their resolution. In addition, the performance of a group of observers with diverse colour vision deficiencies was evaluated while…

  15. The fiddler crab Uca mjoebergi uses colour vision in mate choice.

    PubMed

    Detto, Tanya

    2007-11-22

    Although the role of colour in mate choice is well known, few tests of colour vision have been based on mating behaviour. Females of the fiddler crab Uca mjoebergi have recently been shown to use claw coloration to recognize conspecific males. In this study I demonstrate that the females use colour vision for this task; preferentially approaching yellow claws over grey claws regardless of their intensity while failing to discriminate between yellow claws differing in intensity. This is one of only a handful of studies confirming the involvement of colour vision in mate choice and the first conclusive evidence in fiddler crabs. PMID:17848366

  16. The fiddler crab Uca mjoebergi uses colour vision in mate choice

    PubMed Central

    Detto, Tanya

    2007-01-01

    Although the role of colour in mate choice is well known, few tests of colour vision have been based on mating behaviour. Females of the fiddler crab Uca mjoebergi have recently been shown to use claw coloration to recognize conspecific males. In this study I demonstrate that the females use colour vision for this task; preferentially approaching yellow claws over grey claws regardless of their intensity while failing to discriminate between yellow claws differing in intensity. This is one of only a handful of studies confirming the involvement of colour vision in mate choice and the first conclusive evidence in fiddler crabs. PMID:17848366

  17. Reprint of: Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed

    Rogers, Timothy T; Graham, Kim S; Patterson, Karalyn

    2015-09-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:26051501

  18. Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed

    Rogers, Timothy T; Graham, Kim S; Patterson, Karalyn

    2015-04-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:25637227

  19. Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed Central

    Rogers, Timothy T.; Graham, Kim S.; Patterson, Karalyn

    2015-01-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:25637227

  20. Resilience and vision impairment in older people.

    PubMed

    Thetford, Clare; Bennett, Kate M; Hodge, Suzanne; Knox, Paul C; Robinson, Jude

    2015-12-01

    Some people fare better than others when faced with adversity; they appear to be more 'resilient'. This article explores the concept of resilience in the context of vision impairment using two linked sets of narrative interview data from 2007 to 2010. Three case studies were analysed in detail using a framework approach based upon a social-ecological model of resilience and vision impairment. Within the model a range of assets and resources are identified which influence an individual's capacity for resilience. A set of criteria were used to establish the extent to which each individual appeared to be resilient at each point in time. Analysis revealed that it is not merely the presence or absence of individual, social, and community resources - but how these resources interact with each other - that influences resilience and can create a risk to wellbeing. To possess only some of these resources is not sufficient; there is a co-dependency between these resources which requires the presence of other resources for resilience to be achieved. Resilience is not a fixed state; individuals can become more or less resilient as their circumstances and resources change over time. We suggest that the concept of resilience has much to offer the field of vision impairment as it allows the identification of enablers as well as areas of barriers to improving people's health and wellbeing and suggests further opportunities for service providers to engage with clients, even those who appear to be supported, as people's social, economic and emotional landscapes continue to change over time, rather than identifying deficit. PMID:26568213

  1. Polymorphism of the long-wavelength cone in normal human colour vision

    NASA Astrophysics Data System (ADS)

    Neitz, Jay; Jacobs, Gerald H.

    1986-10-01

    Colour vision is based on the presence of multiple classes of cone each of which contains a different type of photopigment1. Colour matching tests have long revealed that the normal human has three cone types. Results from these tests have also been used to provide estimates of cone spectral sensitivities2. There are significant variations in colour matches made by individuals whose colour vision is classified as normal3-6. Some of this is due to individual differences in preretinal absorption and photopigment density, but some is also believed to arise because there is variation in the spectral positioning of the cone pigments among those who have normal colour vision. We have used a sensitive colour matching test to examine the magnitude and nature of this individual variation and here report evidence for the existence of two different long-wavelength cone mechanisms in normal humans. The different patterns of colour matches made by male and female subjects indicate these two mechanisms are inherited as an X-chromosome linked trait.

  2. Red-Green Color Vision Impairment in Duchenne Muscular Dystrophy

    PubMed Central

    Costa, Marcelo Fernandes ; Oliveira, Andre Gustavo Fernandes ; Feitosa-Santana, Claudia ; Zatz, Mayana ; Ventura, Dora Fix 

    2007-01-01

    The present study evaluated the color vision of 44 patients with Duchenne muscular dystrophy (DMD) (mean age 14.8 years; SD 4.9) who were submitted to a battery of four different color tests: Cambridge Colour Test (CCT), Neitz Anomaloscope, Ishihara, and American Optical Hardy-Rand-Rittler (AO H-R-R). Patients were divided into two groups according to the region of deletion in the dystrophin gene: upstream of exon 30 (n=12) and downstream of exon 30 (n=32). The control group was composed of 70 age-matched healthy male subjects with no ophthalmological complaints. Of the patients with DMD, 47% (21/44) had a red-green color vision defect in the CCT, confirmed by the Neitz Anomaloscope with statistical agreement (P<.001). The Ishihara and the AO H-R-R had a lower capacity to detect color defects—5% and 7%, respectively, with no statistical similarity between the results of these two tests nor between CCT and Anomaloscope results (P>.05). Of the patients with deletion downstream of exon 30, 66% had a red-green color defect. No color defect was found in the patients with deletion upstream of exon 30. A negative correlation between the color thresholds and age was found for the controls and patients with DMD, suggesting a nonprogressive color defect. The percentage (66%) of patients with a red-green defect was significantly higher than the expected <10% for the normal male population (P<.001). In contrast, patients with DMD with deletion upstream of exon 30 had normal color vision. This color defect might be partially explained by a retina impairment related to dystrophin isoform Dp260. PMID:17503325

  3. The intensity threshold of colour vision in a passerine bird, the blue tit (Cyanistes caeruleus).

    PubMed

    Gomez, Doris; Grgoire, Arnaud; Del Rey Granado, Maria; Bassoul, Marine; Degueldre, David; Perret, Philippe; Doutrelant, Claire

    2014-11-01

    Many vertebrates use colour vision for vital behaviour but their visual performance in dim light is largely unknown. The light intensity threshold of colour vision is known only for humans, horses and two parrot species. Here, we first explore this threshold in a passerine bird, the blue tit (Cyanistes caeruleus). Using classic conditioning of colour cues to food rewards in three individuals, we find a threshold ranging from 0.05 to 0.2 cd m(-2). Results are comparable to the two previously tested bird species. For tits, nest light conditions probably exceed that threshold, at least after sunrise. These results shed new light on the lively debate questioning the visual performance of cavity nesters and the evolutionary significance of egg and chick coloration. Although this needs further investigation, it is possible that blue tits exploit both colour and brightness cues when viewing their eggs, chicks or conspecifics in their nests. PMID:25214487

  4. Loss of form vision impairs spatial imagery

    PubMed Central

    Occelli, Valeria; Lin, Jonathan B.; Lacey, Simon; Sathian, K.

    2014-01-01

    Previous studies have reported inconsistent results when comparing spatial imagery performance in the blind and the sighted, with some, but not all, studies demonstrating deficits in the blind. Here, we investigated the effect of visual status and individual preferences (cognitive style) on performance of a spatial imagery task. Participants with blindness resulting in the loss of form vision at or after age 6, and age- and gender-matched sighted participants, performed a spatial imagery task requiring memorization of a 4 4 lettered matrix and subsequent mental construction of shapes within the matrix from four-letter auditory cues. They also completed the Santa Barbara Sense of Direction Scale (SBSoDS) and a self-evaluation of cognitive style. The sighted participants also completed the Object-Spatial Imagery and Verbal Questionnaire (OSIVQ). Visual status affected performance on the spatial imagery task: the blind performed significantly worse than the sighted, independently of the age at which form vision was completely lost. Visual status did not affect the distribution of preferences based on self-reported cognitive style. Across all participants, self-reported verbalizer scores were significantly negatively correlated with accuracy on the spatial imagery task. There was a positive correlation between the SBSoDS score and accuracy on the spatial imagery task, across all participants, indicating that a better sense of direction is related to a more proficient spatial representation and that the imagery task indexes ecologically relevant spatial abilities. Moreover, the older the participants were, the worse their performance was, indicating a detrimental effect of age on spatial imagery performance. Thus, spatial skills represent an important target for rehabilitative approaches to visual impairment, and individual differences, which can modulate performance, should be taken into account in such approaches. PMID:24678294

  5. REVIEW ARTICLE: Optical and developmental constraints on colour vision with lens eyes

    NASA Astrophysics Data System (ADS)

    Kröger, Ronald H. H.

    2000-11-01

    Longitudinal chromatic aberration (LCA) is present in all animal lens eyes and is a limiting factor for colour vision. It is discussed how natural evolution has dealt with the problem of chromatic defocus in ways entirely different from technical solutions. Adaptations to LCA are present in the spectral sensitivities of photoreceptors, the architecture of the retina, the lens and the shape of the pupil. These adaptations raise interesting questions in developmental and cell biology, as well as regarding the evolution of lens eyes and colour vision. It is suggested that LCA has been a limiting factor in the evolution of the human visual system.

  6. A complex carotenoid palette tunes avian colour vision.

    PubMed

    Toomey, Matthew B; Collins, Aaron M; Frederiksen, Rikard; Cornwall, M Carter; Timlin, Jerilyn A; Corbo, Joseph C

    2015-10-01

    The brilliantly coloured cone oil droplets of the avian retina function as long-pass cut-off filters that tune the spectral sensitivity of the photoreceptors and are hypothesized to enhance colour discrimination and improve colour constancy. Although it has long been known that these droplets are pigmented with carotenoids, their precise composition has remained uncertain owing to the technical challenges of measuring these very small, dense and highly refractile optical organelles. In this study, we integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken (Gallus gallus). We find that each of the four carotenoid-containing droplet types consists of a complex mixture of carotenoids, with a single predominant carotenoid determining the wavelength of the spectral filtering cut-off. Consistent with previous reports, we find that the predominant carotenoid type in the oil droplets of long-wavelength-sensitive, medium-wavelength-sensitive and short-wavelength-sensitive type 2 cones are astaxanthin, zeaxanthin and galloxanthin, respectively. In addition, the oil droplet of the principal member of the double cone contains a mixture of galloxanthin and two hydroxycarotenoids (lutein and zeaxanthin). Short-wavelength-absorbing apocarotenoids are present in all of the droplet types, providing filtering of light in a region of the spectrum where filtering by hydroxy- and ketocarotenoids may be incomplete. Thus, birds rely on a complex palette of carotenoid pigments within their cone oil droplets to achieve finely tuned spectral filtering. PMID:26446559

  7. Vision impairment in the Pacific region

    PubMed Central

    Keeffe, J E; Konyama, K; Taylor, H R

    2002-01-01

    The Western Pacific region is one of great diversity, containing the most populous country, China, and many small Pacific island countries. This review describes the prevalence of blindness and vision loss, illustrates the changing trends in the important causes of vision loss and blindness, and the stages of development of the delivery of eye care services across this region. PMID:12034678

  8. Vision impairment and dual sensory problems in middle age

    PubMed Central

    Dawes, Piers; Dickinson, Christine; Emsley, Richard; Bishop, Paul; Cruickshanks, Karen; Edmondson-Jones, Mark; McCormack, Abby; Fortnum, Heather; Moore, David R.; Norman, Paul; Munro, Kevin

    2014-01-01

    Purpose Vision and hearing impairments are known to increase in middle age. In this study we describe the prevalence of vision impairment and dual sensory impairment in UK adults aged 40 to 69 years in a very large and recently ascertained data set. The associations between vision impairment, age, sex, socioeconomic status, and ethnicity are reported. Methods This research was conducted using the UK Biobank Resource, with subsets of UK Biobank data analysed with respect to self-report of eye problems and glasses use. Better-eye visual acuity with habitually worn refractive correction was assessed with a logMAR chart (n = 116,682). Better-ear speech reception threshold was measured with an adaptive speech in noise test, the Digit Triplet Test (n = 164,770). Prevalence estimates were weighted with respect to UK 2001 Census data. Results Prevalence of mild visual impairment and low vision was estimated at 15.2% (95% CI 14.9–15.5%) and 0.9% (95% CI 0.8–1.0%), respectively. Use of glasses was 88.0% (95% CI 87.9–88.1%). The prevalence of dual sensory impairment was 3.1% (95% CI 3.0–3.2%) and there was a nine-fold increase in the prevalence of dual sensory problems between the youngest and oldest age groups. Older adults, those from low socioeconomic and ethnic minority backgrounds were most at risk for vision problems. Conclusions Mild vision impairment is common in middle aged UK adults, despite widespread use of spectacles. Possible barriers to optometric care for those from low socioeconomic and ethnic minority backgrounds may require attention. A higher than expected prevalence of dual impairment suggests that hearing and vision problems share common causes. Optometrists should consider screening for hearing problems, particularly among older adults. PMID:24888710

  9. Project VISION: Visually Impaired Students and Internet Opportunities Now.

    ERIC Educational Resources Information Center

    Kapperman, Gaylen; And Others

    Project VISION (Visually Impaired Students and Internet Opportunities Now) was a 2-year effort to develop and test methods and strategies by which blind and visually impaired students can use assistive technology to gain access to the resources found on the Internet. The project produced a manual and a videotape. Nine students were provided with

  10. Theory and practice of colour vision testing: A review. Part 2

    PubMed Central

    Lakowski, R.

    1969-01-01

    Lakowski, R. (1969).Brit. J. industr. Med.,26, 265-288. Theory and practice of colour vision testing: A review. Part 2. The more modern tests of colour confusion, hue discrimination, metamerism, and special aptitudes measure a wide variety of attributes. Norms, including variations among normal as well as among defective observers, are given for each test, along with any other information we require to understand them. Finally there is the problem of choice, and factors influencing it, of which tests should be used in different circumstances. Some advice is given on the most useful combinations of tests. PMID:4899666

  11. Beyond W3C: TruVision--Enhanced Online Learning for People Blind or Vision Impaired.

    ERIC Educational Resources Information Center

    Bate, Frank; Oliver, Ron

    This paper describes the design and development of TruVision, an online learning environment designed to enable blind and vision impaired students to develop skills and expertise in elementary and advanced information processing strategies to enable them to seek full-time employment within industry in such positions as administrative assistants,

  12. Dichromatic colour vision in wallabies as characterised by three behavioural paradigms.

    PubMed

    Ebeling, Wiebke; Hemmi, Jan M

    2014-01-01

    Despite lacking genetic evidence of a third cone opsin in the retina of any Australian marsupial, most species tested so far appear to be trichromatic. In the light of this, we have re-examined colour vision of the tammar wallaby which had previously been identified as a dichromat. Three different psychophysical tests, based on an operant conditioning paradigm, were used to confirm that colour perception in the wallaby can be predicted and conclusively explained by the existence of only two cone types. Firstly, colour-mixing experiments revealed a Confusion Point between the three primary colours of a LCD monitor that can be predicted by the cone excitation ratio of the short- and middle-wavelength sensitive cones. Secondly, the wavelength discrimination ability in the wallaby, when tested with monochromatic stimuli, was found to be limited to a narrow range between 440 nm and 500 nm. Lastly, an experiment designed to test the wallaby's ability to discriminate monochromatic lights from a white light provided clear evidence for a Neutral Point around 485 nm where discrimination consistently failed. Relative colour discrimination seemed clearly preferred but it was possible to train a wallaby to perform absolute colour discriminations. The results confirm the tammar wallaby as a dichromat, and so far the only behaviourally confirmed dichromat among the Australian marsupials. PMID:24489742

  13. Dichromatic Colour Vision in Wallabies as Characterised by Three Behavioural Paradigms

    PubMed Central

    Ebeling, Wiebke; Hemmi, Jan M.

    2014-01-01

    Despite lacking genetic evidence of a third cone opsin in the retina of any Australian marsupial, most species tested so far appear to be trichromatic. In the light of this, we have re-examined colour vision of the tammar wallaby which had previously been identified as a dichromat. Three different psychophysical tests, based on an operant conditioning paradigm, were used to confirm that colour perception in the wallaby can be predicted and conclusively explained by the existence of only two cone types. Firstly, colour-mixing experiments revealed a Confusion Point between the three primary colours of a LCD monitor that can be predicted by the cone excitation ratio of the short- and middle-wavelength sensitive cones. Secondly, the wavelength discrimination ability in the wallaby, when tested with monochromatic stimuli, was found to be limited to a narrow range between 440 nm and 500 nm. Lastly, an experiment designed to test the wallaby’s ability to discriminate monochromatic lights from a white light provided clear evidence for a Neutral Point around 485 nm where discrimination consistently failed. Relative colour discrimination seemed clearly preferred but it was possible to train a wallaby to perform absolute colour discriminations. The results confirm the tammar wallaby as a dichromat, and so far the only behaviourally confirmed dichromat among the Australian marsupials. PMID:24489742

  14. Mineralized rods and cones suggest colour vision in a 300 Myr-old fossil fish.

    PubMed

    Tanaka, Gengo; Parker, Andrew R; Hasegawa, Yoshikazu; Siveter, David J; Yamamoto, Ryoichi; Miyashita, Kiyoshi; Takahashi, Yuichi; Ito, Shosuke; Wakamatsu, Kazumasa; Mukuda, Takao; Matsuura, Marie; Tomikawa, Ko; Furutani, Masumi; Suzuki, Kayo; Maeda, Haruyoshi

    2014-01-01

    Vision, which consists of an optical system, receptors and image-processing capacity, has existed for at least 520 Myr. Except for the optical system, as in the calcified lenses of trilobite and ostracod arthropods, other parts of the visual system are not usually preserved in the fossil record, because the soft tissue of the eye and the brain decay rapidly after death, such as within 64 days and 11 days, respectively. The Upper Carboniferous Hamilton Formation (300 Myr) in Kansas, USA, yields exceptionally well-preserved animal fossils in an estuarine depositional setting. Here we show that the original colour, shape and putative presence of eumelanin have been preserved in the acanthodii fish Acanthodes bridgei. We also report on the tissues of its eye, which provides the first record of mineralized rods and cones in a fossil and indicates that this 300 Myr-old fish likely possessed colour vision. PMID:25536302

  15. Global cost of correcting vision impairment from uncorrected refractive error

    PubMed Central

    Fricke, TR; Wilson, DA; Schlenther, G; Naidoo, KS; Resnikoff, S; Frick, KD

    2012-01-01

    Abstract Objective To estimate the global cost of establishing and operating the educational and refractive care facilities required to provide care to all individuals who currently have vision impairment resulting from uncorrected refractive error (URE). Methods The global cost of correcting URE was estimated using data on the population, the prevalence of URE and the number of existing refractive care practitioners in individual countries, the cost of establishing and operating educational programmes for practitioners and the cost of establishing and operating refractive care facilities. The assumptions made ensured that costs were not underestimated and an upper limit to the costs was derived using the most expensive extreme for each assumption. Findings There were an estimated 158 million cases of distance vision impairment and 544 million cases of near vision impairment caused by URE worldwide in 2007. Approximately 47?000 additional full-time functional clinical refractionists and 18?000 ophthalmic dispensers would be required to provide refractive care services for these individuals. The global cost of educating the additional personnel and of establishing, maintaining and operating the refractive care facilities needed was estimated to be around 20?000 million United States dollars (US$) and the upper-limit cost was US$28?000 million. The estimated loss in global gross domestic product due to distance vision impairment caused by URE was US$202?000 million annually. Conclusion The cost of establishing and operating the educational and refractive care facilities required to deal with vision impairment resulting from URE was a small proportion of the global loss in productivity associated with that vision impairment. PMID:23109740

  16. Costs of vision impairment: present and future issues.

    PubMed

    Keeffe, Jill E

    2007-10-01

    There is no standard method for measuring costs of vision impairment. Examples are given of global estimates and from two industrialized countries, Australia and the USA. The comparisons between these countries illustrate how the differences in healthcare systems influence the contribution of direct and indirect costs to the total. Modeling of costs and outcomes (cost-effectiveness analysis) has illustrated the extraordinary benefit of programs to prevent vision loss and blindness. These data need to be used in advocacy for the funding of national Vision 2020: the Right to Sight programs. PMID:20528396

  17. Insights into the Support Services for Students with Vision Impairment

    ERIC Educational Resources Information Center

    Datta, Poulomee; Palmer, Carolyn

    2015-01-01

    There is a general need for research in Australia on whether the support services provided in schools prove useful for students with disabilities (Datta, 2015; O'Rourke & Houghton, 2006), especially students with vision impairment. This qualitative study aimed to provide insights into the influence of the support services delivered in South

  18. Advanced IT Education for the Vision Impaired via e-Learning

    ERIC Educational Resources Information Center

    Armstrong, Helen L.

    2009-01-01

    Lack of accessibility in the design of e-learning courses continues to hinder students with vision impairment. E-learning materials are predominantly vision-centric, incorporating images, animation, and interactive media, and as a result students with acute vision impairment do not have equal opportunity to gain tertiary qualifications or skills

  19. Multiple cone visual pigments and the potential for trichromatic colour vision in two species of elasmobranch.

    PubMed

    Hart, Nathan S; Lisney, Thomas J; Marshall, N Justin; Collin, Shaun P

    2004-12-01

    Elasmobranchs (sharks, skates and rays) are the modern descendents of the first jawed vertebrates and, as apex predators, often occupy the highest trophic levels of aquatic (predominantly marine) ecosystems. However, despite their crucial role in the structure of marine communities, their importance both to commercial and to recreational fisheries, and the inherent interest in their role in vertebrate evolution, very little is known about their visual capabilities, especially with regard to whether or not they have the potential for colour vision. Using microspectrophotometry, we show that the retinae of the giant shovelnose ray (Rhinobatos typus) and the eastern shovelnose ray (Aptychotrema rostrata) contain three spectrally distinct cone visual pigments with wavelengths of maximum absorbance (lambdamax) at 477, 502 and 561 nm and at 459, 492 and 553 nm, respectively. The retinae of R. typus and A. rostrata also contain a single type of rod visual pigment with lambdamax at 504 and 498 nm, respectively. R. typus, living in the same estuarine waters as A. rostrata, were found to have identical visual pigments to R. typus inhabiting coral reef flats, despite a considerable difference in habitat spectral radiance. This is the first time that multiple cone visual pigments have been measured directly in an elasmobranch. The finding raises the possibility that some species are able to discriminate colour--a visual ability traditionally thought to be lacking in this vertebrate class--and it is evident that the visual ecology of elasmobranchs is far more complex than once thought. PMID:15579554

  20. Computer vision-based analysis of foods: a non-destructive colour measurement tool to monitor quality and safety.

    PubMed

    Mogol, Bure Ata; Gkmen, Vural

    2014-05-01

    Computer vision-based image analysis has been widely used in food industry to monitor food quality. It allows low-cost and non-contact measurements of colour to be performed. In this paper, two computer vision-based image analysis approaches are discussed to extract mean colour or featured colour information from the digital images of foods. These types of information may be of particular importance as colour indicates certain chemical changes or physical properties in foods. As exemplified here, the mean CIE a* value or browning ratio determined by means of computer vision-based image analysis algorithms can be correlated with acrylamide content of potato chips or cookies. Or, porosity index as an important physical property of breadcrumb can be calculated easily. In this respect, computer vision-based image analysis provides a useful tool for automatic inspection of food products in a manufacturing line, and it can be actively involved in the decision-making process where rapid quality/safety evaluation is needed. PMID:24288215

  1. The Reliability of the CVI Range: A Functional Vision Assessment for Children with Cortical Visual Impairment

    ERIC Educational Resources Information Center

    Newcomb, Sandra

    2010-01-01

    Children who are identified as visually impaired frequently have a functional vision assessment as one way to determine how their visual impairment affects their educational performance. The CVI Range is a functional vision assessment for children with cortical visual impairment. The purpose of the study presented here was to examine the

  2. Prevalence of Adult Vision Impairment and Age-Related Eye Diseases in America

    MedlinePLUS

    ... and Jobs Prevalence of Adult Vision Impairment and Age-Related Eye Diseases in America Listen (Based on ... populations) Estimated Number of Cases by Vision Problem Age ≥ 40 Total Population ≥ 40 142,648,393 AMD* ...

  3. VISION PROBLEMS IN THE U.S.-PREVALENCE OF ADULT VISION IMPAIRMENT AND AGE-RELATED EYE DISEASES IN AMERICA

    EPA Science Inventory

    Leading causes of vision impairment and blindness in the United States. Diabetic retinopathy? Age-related macular degeneration (AMD)? Cataract? Glaucoma? The Vision Problems in the U.S. study was the result of a 2001 consensus meeting, convened by the National Eye Institute and ...

  4. The Potential Impact of Undiagnosed Vision Impairment on Reading Development in the Early Years of School

    ERIC Educational Resources Information Center

    Thurston, Allen

    2014-01-01

    This article presents a critical review of the literature surrounding the potential impact of undiagnosed and untreated vision impairment on reading development in the early years of primary school. Despite pre-school screening programmes, it is still possible for children to enter school with undiagnosed, uncorrected vision impairments. This can…

  5. The Potential Impact of Undiagnosed Vision Impairment on Reading Development in the Early Years of School

    ERIC Educational Resources Information Center

    Thurston, Allen

    2014-01-01

    This article presents a critical review of the literature surrounding the potential impact of undiagnosed and untreated vision impairment on reading development in the early years of primary school. Despite pre-school screening programmes, it is still possible for children to enter school with undiagnosed, uncorrected vision impairments. This can

  6. The Impact of Residual Vision in Spatial Skills of Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

    2011-01-01

    Loss of vision is believed to have a great impact on the acquisition of spatial knowledge. The aims of the present study are to examine the performance of individuals with visual impairments on spatial tasks and the impact of residual vision on processing these tasks. In all, 28 individuals with visual impairments--blindness or low

  7. The Impact of Residual Vision in Spatial Skills of Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni; Kartasidou, Lefkothea

    2011-01-01

    Loss of vision is believed to have a great impact on the acquisition of spatial knowledge. The aims of the present study are to examine the performance of individuals with visual impairments on spatial tasks and the impact of residual vision on processing these tasks. In all, 28 individuals with visual impairments--blindness or low…

  8. The Perspectives of Singapore Secondary School Students with Vision Impairments towards Their Inclusion in Mainstream Education

    ERIC Educational Resources Information Center

    West, John; Houghton, Stephen; Taylor, Myra; Ling, Phua Kia

    2004-01-01

    Students with vision impairments in Singapore are educated in segregated settings from an early age. On completing primary school these students continue their education in mainstream secondary school settings. This transition requires considerable adjustment on the part of students with vision impairments. The present research explored the social

  9. Position of a 'green-red' hybrid gene in the visual pigment array determines colour-vision phenotype.

    PubMed

    Hayashi, T; Motulsky, A G; Deeb, S S

    1999-05-01

    The X-linked red- and green-pigment genes are arranged in a head-to-tail tandem array. The colour-vision defect of deuteranomaly (in 5% of males of European descent) is associated with a 5'-green-red-3' visual-pigment hybrid gene, which may also exist in males with normal colour vision. To explain why males with a normal red, a normal green and a green-red hybrid gene may have either normal or deutan colour vision, we hypothesized that only the first two genes are expressed and deuteranomaly results only if the green-red hybrid gene occupies the second position and is expressed preferentially over normal green-pigment genes occupying more distal positions. We used long-range PCR amplification and studied 10 deutan males (8 deuteranomalous and 2 deuteranopic) with 3 visual pigment genes (red, green and green-red hybrid) to investigate whether position of the hybrid gene in the array determined gene expression. The green-red hybrid gene was always at the second position (and the first position was always occupied by the red gene). Conversely, in two men with red, green and green-red hybrid genes and normal colour vision, the hybrid gene occupied the third position. When pigment gene mRNA expression was assessed in post-mortem retinae of three men with the red, green and green-red genotype, the green-red hybrid gene was expressed only when located in the second position. We conclude that the green-red hybrid gene will only cause deutan defects when it occupies the second position of the pigment gene array. PMID:10319869

  10. Vision of the active limb impairs bimanual motor tracking in young and older adults

    PubMed Central

    Boisgontier, Matthieu P.; Van Halewyck, Florian; Corporaal, Sharissa H. A.; Willacker, Lina; Van Den Bergh, Veerle; Beets, Iseult A. M.; Levin, Oron; Swinnen, Stephan P.

    2014-01-01

    Despite the intensive investigation of bimanual coordination, it remains unclear how directing vision toward either limb influences performance, and whether this influence is affected by age. To examine these questions, we assessed the performance of young and older adults on a bimanual tracking task in which they matched motor-driven movements of their right hand (passive limb) with their left hand (active limb) according to in-phase and anti-phase patterns. Performance in six visual conditions involving central vision, and/or peripheral vision of the active and/or passive limb was compared to performance in a no vision condition. Results indicated that directing central vision to the active limb consistently impaired performance, with higher impairment in older than young adults. Conversely, directing central vision to the passive limb improved performance in young adults, but less consistently in older adults. In conditions involving central vision of one limb and peripheral vision of the other limb, similar effects were found to those for conditions involving central vision of one limb only. Peripheral vision alone resulted in similar or impaired performance compared to the no vision (NV) condition. These results indicate that the locus of visual attention is critical for bimanual motor control in young and older adults, with older adults being either more impaired or less able to benefit from a given visual condition. PMID:25452727

  11. Exercise and Drinking May Play a Role in Vision Impairment Risk

    MedlinePLUS

    ... May Play a Role in Vision Impairment Risk Mar. 20, 2014 In 2020, the number of people ... smoking, drinking alcohol and staying physically active. The research was conducted as part of the Beaver Dam ...

  12. Facilitating the Inclusion of Children with Vision Impairment: Perspectives of Itinerant Support Teachers

    ERIC Educational Resources Information Center

    Morris, Christine; Sharma, Umesh

    2011-01-01

    Children with vision impairment (VI) and blindness are largely educated in mainstream schools in Australia. Specialist itinerant support teachers--vision (ISTVs) travel from school to school to facilitate the education of these children. The purposes of this study were to examine the barriers that ISTVs face in this role, and to identify

  13. Efficacy of Low Vision Services for Visually Impaired Children.

    ERIC Educational Resources Information Center

    Hofstetter, H. W.

    1991-01-01

    Low vision children (ages 4-19, n=137) were screened, and 77 percent were advised to have comprehensive clinical evaluations or ophthalmology services. The visual capability of the referred children was determined, low vision aids were prescribed for 56 children, and the degree of successful utilization of aids was evaluated. (JDD)

  14. Beauty in the eyes of the beholders: colour vision is tuned to mate preference in the Trinidadian guppy (Poecilia reticulata).

    PubMed

    Sandkam, Benjamin; Young, C Megan; Breden, Felix

    2015-02-01

    A broad range of animals use visual signals to assess potential mates, and the theory of sensory exploitation suggests variation in visual systems drives mate preference variation due to sensory bias. Trinidadian guppies (Poecilia reticulata), a classic system for studies of the evolution of female mate choice, provide a unique opportunity to test this theory by looking for covariation in visual tuning, light environment and mate preferences. Female preference co-evolves with male coloration, such that guppy females from 'low-predation' environments have stronger preferences for males with more orange/red coloration than do females from 'high-predation' environments. Here, we show that colour vision also varies across populations, with 'low'-predation guppies investing more of their colour vision to detect red/orange coloration. In independently colonized watersheds, guppies expressed higher levels of both LWS-1 and LWS-3 (the most abundant LWS opsins) in 'low-predation' populations than 'high-predation' populations at a time that corresponds to differences in cone cell abundance. We also observed that the frequency of a coding polymorphism differed between high- and low-predation populations. Together, this shows that the variation underlying preference could be explained by simple changes in expression and coding of opsins, providing important candidate genes to investigate the genetic basis of female preference variation in this model system. PMID:25556876

  15. Colour vision in the glow-worm Lampyris noctiluca (L.) (Coleoptera: Lampyridae): evidence for a green-blue chromatic mechanism.

    PubMed

    Booth, David; Stewart, Alan J A; Osorio, Daniel

    2004-06-01

    Male glow-worms Lampyris noctiluca find their bioluminescent mates at night by phototaxis. There is good evidence that location of mates by lampyrid beetles is achieved by a single spectral class of photoreceptor, whose spectral sensitivity is tuned to the bioluminescent spectrum emitted by conspecifics, and is achromatic. We ask whether glow-worm phototaxis involves interactions between two spectral classes of photoreceptor. Binary choice experiments were conducted in which males were presented with artificial light stimuli that differ in spectral composition. The normal preference for a green stimulus (lambdamax=555 nm), corresponding to the bioluminescence wavelength produced by signalling females, was significantly reduced by adding a blue (lambdamax=485 nm) component to the signal. This implies an antagonistic interaction between long- and short-wavelength sensitive photoreceptors, suggesting colour vision based on chromatic opponency. Cryosections showed a band of yellow filter pigment in the fronto-dorsal region of the male compound eye, which could severely constrain colour vision in the dim conditions in which the insects signal. This apparent paradox is discussed in the context of the distribution of the pigment within the eye and the photic niche of the species. PMID:15184509

  16. Use of the Simplified Color Video Magnifier by Young Children with Severely Impaired Vision.

    ERIC Educational Resources Information Center

    Muranaka, Yoshio; And Others

    1985-01-01

    A new image magnifier system that enlarges color picture images for visually impaired children consists of home video components following the closed-circuit television model. The technique seems especially effective in enriching visual experience of children with severely impaired vision and bridging the interest development gap between picture

  17. Use of the Simplified Color Video Magnifier by Young Children with Severely Impaired Vision.

    ERIC Educational Resources Information Center

    Muranaka, Yoshio; And Others

    1985-01-01

    A new image magnifier system that enlarges color picture images for visually impaired children consists of home video components following the closed-circuit television model. The technique seems especially effective in enriching visual experience of children with severely impaired vision and bridging the interest development gap between picture…

  18. Is colour cognitive?

    NASA Astrophysics Data System (ADS)

    Skorupski, Peter; Chittka, Lars

    2011-03-01

    In recent years, colour-vision abilities have been rather generously ascribed to various invertebrates and even bacteria. This uncertainty of when to diagnose colour vision stems in part from confusing what colour vision can do with what it is. What colour vision can do is discriminate wavelength independent of intensity. However, if we take this as a definition of what colour vision is, then we might be obliged to conclude that some plants and bacteria have colour vision. Moreover, there is a similar confusion of what are necessary and what are sufficient mechanisms and behavioural abilities for colour vision. To humans, seeing in colour means seeing an image in which objects/lights have chromatic attributes—in contrast to the sensation that we have when viewing monochrome movies, or our experience in dim light when only rod vision is possible. The necessary basic equipment for this is to have at least two types of photoreceptors that differ in spectral sensitivity, and at least one type of spectrally opponent cell to compare the signals from the photoreceptors. Clearly, however, a necessary additional prerequisite for colour vision is to have vision, which entails the identification of shapes, sizes and locations of objects in the world. Thus, if an animal has colour vision, it should see an image in which distinct objects/lights have colour attributes. This distinguishes colour vision from wavelength discrimination, but also from what has historically been called wavelength-specific behaviour: a type of behaviour triggered by fixed configurations of spectral receptor signals; however, we discuss difficulties in diagnosing wavelength-specific behaviour as an indicator of the absence of colour vision. Finally, we discuss whether colour vision, by definition, contains a cognitive dimension for ordering and classifying perceptual experience.

  19. Visual Impairment Secondary to Congenital Glaucoma in Children: Visual Responses, Optical Correction and Use of Low Vision Aids

    PubMed Central

    Haddad, Maria Aparecida Onuki; Sampaio, Marcos Wilson; Oltrogge, Ernst Werner; Kara-José, Newton; Betinjane, Alberto Jorge

    2009-01-01

    INTRODUCTION Congenital glaucoma is frequently associated with visual impairment due to optic nerve damage, corneal opacities, cataracts and amblyopia. Poor vision in childhood is related to global developmental problems, and referral to vision habilitation/rehabilitation services should be without delay to promote efficient management of the impaired vision. OBJECTIVE To analyze data concerning visual response, the use of optical correction and prescribed low vision aids in a population of children with congenital glaucoma. METHOD The authors analyzed data from 100 children with congenital glaucoma to assess best corrected visual acuity, prescribed optical correction and low vision aids. RESULTS Fifty-five percent of the sample were male, 43% female. The mean age was 6.3 years. Two percent presented normal visual acuity levels, 29% mild visual impairment, 28% moderate visual impairment, 15% severe visual impairment, 11% profound visual impairment, and 15% near blindness. Sixty-eight percent received optical correction for refractive errors. Optical low vision aids were adopted for distance vision in 34% of the patients and for near vision in 6%. A manual monocular telescopic system with 2.8 × magnification was the most frequently prescribed low vision aid for distance, and for near vision a +38 diopter illuminated stand magnifier was most frequently prescribed. DISCUSSION AND CONCLUSION Careful low vision assessment and the appropriate prescription of optical corrections and low vision aids are mandatory in children with congenital glaucoma, since this will assist their global development, improving efficiency in daily life activities and promoting social and educational inclusion. PMID:19690654

  20. Colour Perception in ADHD

    ERIC Educational Resources Information Center

    Banaschewski, Tobias; Ruppert, Sinje; Tannock, Rosemary; Albrecht, Bjorn; Becker, Andreas; Uebel, Henrik; Sergeant, Joseph A.; Rothenberger, Aribert

    2006-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children

  1. Frugivory and colour vision in Alouatta seniculus, a trichromatic platyrrhine monkey.

    PubMed

    Regan, B C; Julliot, C; Simmen, B; Viénot, F; Charles-Dominique, P; Mollon, J D

    1998-11-01

    It is a long-standing hypothesis that primate trichromacy evolved to help fruit-eating primates find fruits amongst leaves. We measured the reflectance spectra of fruits eaten by a trichromatic primate, Alouatta seniculus, in the rainforest of French Guiana, as well as those of the leaves that form the natural background to fruits. We develop a method of specifying these natural colour signals in a chromaticity diagram appropriate for A. seniculus. By treating the task facing frugivorous monkeys as a signal detection task, we show that the spectral tuning of the L and M cone pigments in A. seniculus is optimal for detecting fruits amongst leaves. PMID:9893844

  2. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  3. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  4. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  5. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  6. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  7. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  8. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  9. 14 CFR 382.53 - What information must carriers give individuals with a vision or hearing impairment at airports?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false What information must carriers give individuals with a vision or hearing impairment at airports? 382.53 Section 382.53 Aeronautics and Space... information must carriers give individuals with a vision or hearing impairment at airports? (a)(1) As a...

  10. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  11. 14 CFR 382.119 - What information must carriers give individuals with vision or hearing impairment on aircraft?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false What information must carriers give individuals with vision or hearing impairment on aircraft? 382.119 Section 382.119 Aeronautics and Space... carriers give individuals with vision or hearing impairment on aircraft? (a) As a carrier, you must...

  12. Test Anxiety Research: Students with Vision Impairments and Students with Mild Intellectual Disabilities

    ERIC Educational Resources Information Center

    Datta, Poulomee

    2014-01-01

    There is an absence of research on test anxiety in students with disabilities although such testing is taken for granted among students without disabilities. This study investigated the test anxiety of the students in each of the two disability groups, those with vision impairments and those with intellectual disabilities who are placed in

  13. An Overview of a UK Paediatric Visual Impaired Population and Low Vision Aid Provision

    ERIC Educational Resources Information Center

    Theodorou, Nana; Shipman, Tracey

    2013-01-01

    A retrospective study was carried out to evaluate the paediatric visual impaired population attending the Low Vision Clinic at Sheffield Teaching Hospitals NHS Foundation Trust, over a period of 14 years. Data were collected and analysed for children less than 17 years for prevalence, demographics, registration status, aetiologies, and types of

  14. Students with Low Vision Describe Their Visual Impairments and Visual Functioning

    ERIC Educational Resources Information Center

    Guerette, Amy R.; Lewis, Sandra; Mattingly, Cameron

    2011-01-01

    In the study reported here, the responses to a survey that was designed to determine the knowledge of their visual impairment of 51 students with low vision were analyzed. Although the students described their visual weaknesses and strengths, they had limited knowledge of, and difficulty communicating about, the medical aspects of their

  15. Audio from Orbit: The Future of Libraries for Individuals Who Are Blind or Vision Impaired

    ERIC Educational Resources Information Center

    Steer, Michael; Cheetham, Leonie

    2005-01-01

    Free library service is a component of the foundations of democracy, citizenship, economic and social development, scholarship and education, in progressive societies. The evolution of libraries for people who are blind or vision impaired is briefly discussed and an innovative project, a talking book and daily newspaper delivery system that

  16. Audio from Orbit: The Future of Libraries for Individuals Who Are Blind or Vision Impaired

    ERIC Educational Resources Information Center

    Steer, Michael; Cheetham, Leonie

    2005-01-01

    Free library service is a component of the foundations of democracy, citizenship, economic and social development, scholarship and education, in progressive societies. The evolution of libraries for people who are blind or vision impaired is briefly discussed and an innovative project, a talking book and daily newspaper delivery system that…

  17. An Overview of a UK Paediatric Visual Impaired Population and Low Vision Aid Provision

    ERIC Educational Resources Information Center

    Theodorou, Nana; Shipman, Tracey

    2013-01-01

    A retrospective study was carried out to evaluate the paediatric visual impaired population attending the Low Vision Clinic at Sheffield Teaching Hospitals NHS Foundation Trust, over a period of 14 years. Data were collected and analysed for children less than 17 years for prevalence, demographics, registration status, aetiologies, and types of…

  18. Space Vision: Making Astronomy Accessible to Visually Impaired Students

    NASA Astrophysics Data System (ADS)

    Ries, J. G.; Baguio, M. R.; Jurgens, T. D.; Pruett, K. M.

    2004-05-01

    Astronomy, with good reason, is thought of as a visual science. Spectacular images of deep space objects or other worlds of our solar system inspire public interest in Astronomy. People encounter news about the universe during their daily life. Developing concepts about celestial objects presents an extra challenge of abstraction for people with visual impairments. The Texas Space Grant Consortium with educators at the Texas School for the Blind and Visually Impaired have developed a 2 day workshop to be held in April 2004 to help students with visual impairments understand these concepts. Hands-on activities and experiments will emphasize non-visual senses. For example, students will learn about: - Constellations as historical ways of finding one's way across the sky. - The size and structure of the Solar System by building a scale model on a running track. They will also: - Plan a planetary exploration mission. - Explore wave phenomenon using heat and sound waves. In preparation for the workshop we worked with teens involved in the countywide 4-H Teens Leading with Character (TLC) program to create the tactile materials necessary for the activities. The teens attended solar system education training so they would have the skills necessary to make the tactile displays to be used during the workshop. The results and evaluation of the workshop will be presented at the meeting. Touch the Universe: A NASA Braille Book of Astronomy inspired this workshop, and it is supported by HST Grant HST-ED-90255.01-A.

  19. Seroepidemiology of Toxocara Infection in Patients With Vision Impairment and Blindness in Durango, Mexico

    PubMed Central

    Alvarado-Esquivel, Cosme; Hernandez-Tinoco, Jesus; Sanchez-Anguiano, Luis Francisco

    2015-01-01

    Background Toxocara infection is a cause of vision impairment and blindness. We aimed to determine the seroprevalence and correlates of Toxocara infection in patients suffering from vision impairment and blindness in Durango City, Mexico. Methods Through a cross-sectional seroprevalence study, 204 patients with vision impairment and 19 blind patients were studied for the presence of anti-Toxocara IgG antibodies in Durango City, Mexico. Seroprevalence association with socio-demographic, housing, clinical, and behavioral characteristics of participants was also investigated. Results Five (2.5%) of the 204 patients with vision impairment, and none of the 19 patients with blindness were positive for anti-Toxocara IgG antibodies. In total, five of the 223 (2.2%) patients were positive for anti-Toxocara IgG antibodies. Seropositivity to Toxocara was not associated with age, sex, educational level, socio-economic status, presence of underlying diseases or behavioral characteristics of the patients. In contrast, multivariate analysis showed that Toxocara seropositivity was associated with living in a house with soil floor (odds ratio (OR) = 11.14; 95% confidence interval (CI): 1.57 - 78.74; P = 0.01). Conclusions This is the first report of Toxocara exposure in patients with vision impairment and blindness in Mexico, and of an association of Toxocara exposure with living in a house with soil floors. Results suggest a low Toxocara exposure in these patients in Durango, Mexico. The risk factor associated with Toxocara exposure identified in this study warrants for further investigation. PMID:25584103

  20. The effects of simulated vision impairments on the cone of gaze.

    PubMed

    Hecht, Heiko; Hrichs, Jenny; Sheldon, Sarah; Quint, Jessilin; Bowers, Alex

    2015-10-01

    Detecting the gaze direction of others is critical for many social interactions. We explored factors that may make the perception of mutual gaze more difficult, including the degradation of the stimulus and simulated vision impairment. To what extent do these factors affect the complex assessment of mutual gaze? Using an interactive virtual head whose eye direction could be manipulated by the subject, we conducted two experiments to assess the effects of simulated vision impairments on mutual gaze. Healthy subjects had to demarcate the center and the edges of the cone of gaze-that is, the range of gaze directions that are accepted for mutual gaze. When vision was impaired by adding a semitransparent white contrast reduction mask to the display (Exp. 1), judgments became more variable and more influenced by the head direction (indicative of a compensation strategy). When refractive blur was added (Exp. 1), the gaze cone shrank from 12.9 (no blur) to 11.3 (3-diopter lens), which cannot be explained by a low-level process but might reflect a tightening of the criterion for mutual gaze as a response to the increased uncertainty. However, the overall effects of the impairments were relatively modest. Elderly subjects (Exp. 2) produced more variability but did not differ qualitatively from the younger subjects. In the face of artificial vision impairments, compensation mechanisms and criterion changes allow us to perform better in mutual gaze perception than would be predicted by a simple extrapolation from the losses in basic visual acuity and contrast sensitivity. PMID:26018645

  1. The Influence of Manifest Strabismus and Stereoscopic Vision on Non-Verbal Abilities of Visually Impaired Children

    ERIC Educational Resources Information Center

    Gligorovic, Milica; Vucinic, Vesna; Eskirovic, Branka; Jablan, Branka

    2011-01-01

    This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest

  2. Effectiveness of screening older people for impaired vision in community setting: systematic review of evidence from randomised controlled trials

    PubMed Central

    Smeeth, Liam; Iliffe, Steve

    1998-01-01

    Objective: To assess whether population screening for impaired vision among older people in the community leads to improvements in vision. Design: Systematic review of randomised controlled trials of population screening in the community that included any assessment of vision or visual function with at least 6 months follow up. Subjects: Adults aged 65 or over. Main outcome measure: Proportions with visual impairment in intervention and control groups with any method of assessing visual impairment. Results: There were no trials that primarily assessed visual screening. Outcome data on vision were available for 3494 people in five trials of multiphasic assessment. All the trials used self reported measures for vision impairment, both as screening tools and as outcome measures. The inclusion of a visual screening component in the assessments did not result in improvements in self reported visual problems (pooled odds ratio 1.04: 95% confidence interval 0.89 to 1.22). A small reduction (11%) in the number of older people with self reported visual problems cannot be excluded. Conclusions: Screening of asymptomatic older people in the community is not justified on present evidence. Visual impairment in this age group can usually be reduced with treatment. It is unclear why no benefit was seen. Further work is needed to clarify what interventions are appropriate for older people with unreported impairment of vision. Key messages Impaired vision is common among older people and has a variety of adverse associations General practitioners are currently obliged to offer an annual assessment of vision as part of the 75 and over programme Evidence for effectiveness of visual screening is lacking, but a small beneficial effect cannot be excluded The continued inclusion of screening for impaired vision in screening programmes for older people is not supported by the evidence Further work is needed to clarify appropriate interventions for older people with unreported visual impairment PMID:9522788

  3. High Tech Aids Low Vision: A Review of Image Processing for the Visually Impaired

    PubMed Central

    Moshtael, Howard; Aslam, Tariq; Underwood, Ian; Dhillon, Baljean

    2015-01-01

    Recent advances in digital image processing provide promising methods for maximizing the residual vision of the visually impaired. This paper seeks to introduce this field to the readership and describe its current state as found in the literature. A systematic search revealed 37 studies that measure the value of image processing techniques for subjects with low vision. The techniques used are categorized according to their effect and the principal findings are summarized. The majority of participants preferred enhanced images over the original for a wide range of enhancement types. Adapting the contrast and spatial frequency content often improved performance at object recognition and reading speed, as did techniques that attenuate the image background and a technique that induced jitter. A lack of consistency in preference and performance measures was found, as well as a lack of independent studies. Nevertheless, the promising results should encourage further research in order to allow their widespread use in low-vision aids. PMID:26290777

  4. Development of a quantitative method to measure vision in children with chronic cortical visual impairment.

    PubMed Central

    Good, W V

    2001-01-01

    PURPOSE: Cortical visual impairment (CVI) is the most common cause of bilateral vision impairment in children in Western countries. Better quantitative tools for measuring vision are needed to assess these children, to allow measurement of their visual deficit, and to monitor their response to treatment and rehabilitation. The author performed a series of experiments to assess the use of the sweep visual evoked potential (VEP) as a quantitative tool for measuring vision in CVI. METHODS: The first experiment was a reliability measure (test/retest) of VEP grating acuity thresholds of 23 children with CVI. To validate the VEP procedure, VEP grating acuity was compared to a clinical measure of vision, the Huo scale, and to a psychophysical measure of vision, the Teller Acuity Card procedure. Finally, the sweep VEP was tested as a tool for defining optimal luminance conditions for grating acuity in 13 children with CVI, by measuring grating thresholds under 2 different luminance conditions: 50 and 100 candela per square meter (cd/m2). RESULTS: Retest thresholds were similar to original thresholds (r2 = 0.662; P = .003, 1-tailed t test). Grating VEP measures correlate significantly with the clinical index (r2 = 0.63; P = .00004). Teller acuity measurements are also similar to VEP measures in children (r2 = 0.64; P = .0005) but show lower acuities compared to the VEP for children with particularly low vision. Finally, 3 of 13 children tested under 2 background luminance conditions showed paradoxical improvement in grating threshold with dimmer luminance. CONCLUSIONS: The sweep VEP tool is a reliable and valid means for measuring grating acuity in children with CVI. The tool also shows promise as a means of determining the optimal visual environment for children with CVI. PMID:11797314

  5. Sinus Balloon Dilation as Treatment for Acute Sphenoid Sinusitis with Impaired Vision for a Child

    PubMed Central

    Zhao, Yin; Chen, Kangbing; Wang, Zonggui

    2016-01-01

    This paper is about sinus balloon dilatation in treatment of acute left sphenoid sinusitis with left impaired vision in a child. Balloon catheter dilatation (BCD) of the sinus ostia is a new technique. It has been shown to be a minimally invasive technique to manage chronic sinusitis. However, this method is rarely used in the treatment of acute sinusitis. So far, we know of no reported cases of sinus balloon dilatation in treatment of this case, especially for children. PMID:27006660

  6. The Use of a Tactile-Vision Sensory Substitution System as an Augmentative Tool for Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Williams, Michael D.; Ray, Christopher T.; Griffith, Jennifer; De l'Aune, William

    2011-01-01

    The promise of novel technological strategies and solutions to assist persons with visual impairments (that is, those who are blind or have low vision) is frequently discussed and held to be widely beneficial in countless applications and daily activities. One such approach involving a tactile-vision sensory substitution modality as a mechanism to

  7. The Use of a Tactile-Vision Sensory Substitution System as an Augmentative Tool for Individuals with Visual Impairments

    ERIC Educational Resources Information Center

    Williams, Michael D.; Ray, Christopher T.; Griffith, Jennifer; De l'Aune, William

    2011-01-01

    The promise of novel technological strategies and solutions to assist persons with visual impairments (that is, those who are blind or have low vision) is frequently discussed and held to be widely beneficial in countless applications and daily activities. One such approach involving a tactile-vision sensory substitution modality as a mechanism to…

  8. Comparison on testability of visual acuity, stereo acuity and colour vision tests between children with learning disabilities and children without learning disabilities in government primary schools

    PubMed Central

    Abu Bakar, Nurul Farhana; Chen, Ai-Hong

    2014-01-01

    Context: Children with learning disabilities might have difficulties to communicate effectively and give reliable responses as required in various visual function testing procedures. Aims: The purpose of this study was to compare the testability of visual acuity using the modified Early Treatment Diabetic Retinopathy Study (ETDRS) and Cambridge Crowding Cards, stereo acuity using Lang Stereo test II and Butterfly stereo tests and colour perception using Colour Vision Test Made Easy (CVTME) and Ishihara's Test for Colour Deficiency (Ishihara Test) between children in mainstream classes and children with learning disabilities in special education classes in government primary schools. Materials and Methods: A total of 100 primary school children (50 children from mainstream classes and 50 children from special education classes) matched in age were recruited in this cross-sectional comparative study. The testability was determined by the percentage of children who were able to give reliable respond as required by the respective tests. Unable to test was defined as inappropriate response or uncooperative despite best efforts of the screener. Results: The testability of the modified ETDRS, Butterfly stereo test and Ishihara test for respective visual function tests were found lower among children in special education classes (P < 0.001) but not in Cambridge Crowding Cards, Lang Stereo test II and CVTME. Conclusion: Non verbal or matching approaches were found to be more superior in testing visual functions in children with learning disabilities. Modifications of vision testing procedures are essential for children with learning disabilities. PMID:24008790

  9. Prevalence of attention-deficit/hyperactivity disorder among children with vision impairment

    PubMed Central

    DeCarlo, Dawn K.; Bowman, Ellen; Monroe, Cara; Kline, Robert; McGwin, Gerald; Owsley, Cynthia

    2014-01-01

    Purpose To evaluate the prevalence of parent-reported attention-deficit/hyperactivity disorder (ADHD) in two clinics in Alabama serving children with vision impairment. Methods The medical records of children 4–17 years of age attending the Alabama School for the Blind (ASB) during the 2010–2011 school year or seen at the University of Alabama at Birmingham (UAB) Center for Low Vision Rehabilitation between 2006 and 2010 were retrospectively reviewed. Sociodemographics, ocular characteristics, and parental report of ADHD diagnosis were obtained. The prevalence of ADHD was compared to national and state figures for age-similar children regardless of comorbidities. The prevalence of ADHD, sociodemographic, and ocular characteristics was also compared between clinical sites. Results A total of 264 children participated in the study (95 from ASB and 169 from UAB). The prevalence of ADHD among children with visual acuity better than hand motion (n = 245) was 22.9%, which is higher than reported state (14.3%) and national prevalence (9.5%) for children in this age range. The prevalence was similar at ASB (22.4%) and UAB (23.1%). Those with ADHD were similar to those without ADHD with respect to age, sex, and race. Children with ADHD were significantly less likely to have nystagmus and more likely to have better visual acuity (P < 0.05). The prevalence of ADHD among the 19 participants with total or near total vision loss (all from ASB) was 10.5%. Conclusions Our analyses suggest that children with vision impairment may be more likely to be diagnosed with ADHD than children in the general population. PMID:24568975

  10. Device for diagnosis and treatment of impairments on binocular vision and stereopsis

    NASA Astrophysics Data System (ADS)

    Bahn, Jieun; Choi, Yong-Jin; Son, Jung-Young; Kodratiev, N. V.; Elkhov, Victor A.; Ovechkis, Yuri N.; Chung, Chan-sup

    2001-06-01

    Strabismus and amblyopia are two main impairments of our visual system, which are responsible for the loss of stereovision. A device is developed for diagnosis and treatment of strabismus and amblyopia, and for training and developing stereopsis. This device is composed of a liquid crystal glasses (LCG), electronics for driving LCG and synchronizing with an IBM PC, and a special software. The software contains specially designed patterns and graphics for enabling to train and develop stereopsis, and do objective measurement of some stereoscopic vision parameters such as horizontal and vertical phoria, fusion, fixation disparity, and stereoscopic visual threshold.

  11. Early Chronic Low-Level Methylmercury Poisoning in Monkeys Impairs Spatial Vision

    NASA Astrophysics Data System (ADS)

    Rice, Deborah C.; Gilbert, Steven G.

    1982-05-01

    Five monkeys were treated from birth with oral doses of mercury as methylmercury (50 micrograms per kilogram of body weight per day); concentrations in the blood peaked at 1.2 to 1.4 parts per million; and declined after weaning from infant formula to a steady level of 0.6 to 0.9 part per million. There were no overt signs of toxicity. When tested between 3 and 4 years of age under conditions of both high and low luminance, treated monkeys exhibited spatial vision that was impaired compared with that of control monkeys.

  12. Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.

    PubMed

    Lampert, E J; Andorra, M; Torres-Torres, R; Ortiz-Pérez, S; Llufriu, S; Sepúlveda, M; Sola, N; Saiz, A; Sánchez-Dalmau, B; Villoslada, P; Martínez-Lapiscina, Elena H

    2015-11-01

    Multiple Sclerosis (MS) results in color vision impairment regardless of optic neuritis (ON). The exact location of injury remains undefined. The objective of this study is to identify the region leading to dyschromatopsia in MS patients' NON-eyes. We evaluated Spearman correlations between color vision and measures of different regions in the afferent visual pathway in 106 MS patients. Regions with significant correlations were included in logistic regression models to assess their independent role in dyschromatopsia. We evaluated color vision with Hardy-Rand-Rittler plates and retinal damage using Optical Coherence Tomography. We ran SIENAX to measure Normalized Brain Parenchymal Volume (NBPV), FIRST for thalamus volume and Freesurfer for visual cortex areas. We found moderate, significant correlations between color vision and macular retinal nerve fiber layer (rho = 0.289, p = 0.003), ganglion cell complex (GCC = GCIP) (rho = 0.353, p < 0.001), thalamus (rho = 0.361, p < 0.001), and lesion volume within the optic radiations (rho = -0.230, p = 0.030). Only GCC thickness remained significant (p = 0.023) in the logistic regression model. In the final model including lesion load and NBPV as markers of diffuse neuroaxonal damage, GCC remained associated with dyschromatopsia [OR = 0.88 95 % CI (0.80-0.97) p = 0.016]. This association remained significant when we also added sex, age, and disease duration as covariates in the regression model. Dyschromatopsia in NON-eyes is due to damage of retinal ganglion cells (RGC) in MS. Color vision can serve as a marker of RGC damage in MS. PMID:26259563

  13. No rainbow for grey bamboo sharks: evidence for the absence of colour vision in sharks from behavioural discrimination experiments.

    PubMed

    Schluessel, V; Rick, I P; Plischke, K

    2014-11-01

    Despite convincing data collected by microspectrophotometry and molecular biology, rendering sharks colourblind cone monochromats, the question of whether sharks can perceive colour had not been finally resolved in the absence of any behavioural experiments compensating for the confounding factor of brightness. The present study tested the ability of juvenile grey bamboo sharks to perceive colour in an experimental design based on a paradigm established by Karl von Frisch using colours in combination with grey distractor stimuli of equal brightness. Results showed that contrasts but no colours could be discriminated. Blue and yellow stimuli were not distinguished from a grey distractor stimulus of equal brightness but could be distinguished from distractor stimuli of varying brightness. In addition, different grey stimuli were distinguished significantly above chance level from one another. In conclusion, the behavioural results support the previously collected physiological data on bamboo sharks, which mutually show that the grey bamboo shark, like several marine mammals, is a cone monochromate and colourblind. PMID:25245080

  14. The Hong Kong vision study: a pilot assessment of visual impairment in adults.

    PubMed Central

    Van Newkirk, M R

    1997-01-01

    PURPOSE: The Hong Kong Adult Vision Pilot Study is a population based study of the distribution and determinants of eye disease in a random sample of the Chinese population age 40 and over. The present pilot study identifies the extent and causes of visual loss using methods developed in the United States and Australia. The pilot study uses the prevalence data to estimate the sample size necessary to predict the size of an effect a larger study may detect and the confidence with which that effect may be considered and the standard deviation of the Hong Kong population. The smallest detectable odds ratios were calculated based on known risk factor prevalence rates of the pilot study. METHODS: Hong Kong Chinese residents aged 40 and over in 2 random cluster sites were identified by private household census. The examinations were performed at one location and included, health history and habits, presenting and best corrected LogMar vision, Humphrey visual field and IOP measurement, dilated slit lamp, fundus examination, fundus photography and echography. RESULTS: In the two test sites, 355 people were examined of the 441 eligible residents (81% response). 76.6% of the population reported a change in vision in the last 10 years; 45% had not sought examination. 4.54% had vision less than 20/60. This was caused by: myopic choroidal degeneration (31%), cataract (19%), cataract + ARM (19%), ARMD (19%), glaucoma (6%), and corneal disease (6%). Vision loss increased significantly with age. Vision loss was more common in older women than in older men. The prevalence rates calculated from the pilot study data were used, requiring a relative precision of 95% and +/- 20% confidence interval of the prevalence rates, indicate that a sample size of 2500 would be a good number for a larger study. CONCLUSIONS: The methods developed in the United States and Australia for completing eye disease prevalence studies are applicable in Hong Kong. Vision loss is increasingly common in older people and the percent of visual impairment in Hong Kong is higher than studies in the US and Australia. As the population ages demands on the health care systems will increase. The results from this pilot warrant continuation of the study. Efforts must be directed toward prevention of visual loss. PMID:9440191

  15. The effect of gender and level of vision on the physical activity level of children and adolescents with visual impairment.

    PubMed

    Aslan, Ummuhan Bas; Calik, Bilge Basakc?; Kiti?, Ali

    2012-01-01

    This study was planned in order to determine physical activity levels of visually impaired children and adolescents and to investigate the effect of gender and level of vision on physical activity level in visually impaired children and adolescents. A total of 30 visually impaired children and adolescents (16 low vision and 14 blind) aged between 8 and 16 years participated in the study. The physical activity level of cases was evaluated with a physical activity diary (PAD) and one-mile run/walk test (OMR-WT). No difference was found between the PAD and the OMR-WT results of low vision and blind children and adolescents. The visually impaired children and adolescents were detected not to participate in vigorous physical activity. A difference was found in favor of low vision boys in terms of mild, moderate activities and OMR-WT durations. However, no difference was found between physical activity levels of blind girls and boys. The results of our study suggested that the physical activity level of visually impaired children and adolescents was low, and gender affected physical activity in low vision children and adolescents. PMID:22699253

  16. Prevalence of vision impairment and refractive error in school children in Ba Ria Vung Tau province, Vietnam

    PubMed Central

    Paudel, Prakash; Ramson, Prasidh; Naduvilath, Thomas; Wilson, David; Phuong, Ha Thanh; Ho, Suit M; Giap, Nguyen V

    2014-01-01

    Background To assess the prevalence of vision impairment and refractive error in school children 1215 years of age in Ba Ria Vung Tau province, Vietnam. Design Prospective, cross-sectional study. Participants 2238 secondary school children. Methods Subjects were selected based on stratified multistage cluster sampling of 13 secondary schools from urban, rural and semi-urban areas. The examination included visual acuity measurements, ocular motility evaluation, cycloplegic autorefraction, and examination of the external eye, anterior segment, media and fundus. Main Outcome Measures Visual acuity and principal cause of vision impairment. Results The prevalence of uncorrected and presenting visual acuity ?6/12 in the better eye were 19.4% (95% confidence interval, 12.526.3) and 12.2% (95% confidence interval, 8.815.6), respectively. Refractive error was the cause of vision impairment in 92.7%, amblyopia in 2.2%, cataract in 0.7%, retinal disorders in 0.4%, other causes in 1.5% and unexplained causes in the remaining 2.6%. The prevalence of vision impairment due to myopia in either eye (0.50 diopter or greater) was 20.4% (95% confidence interval, 12.828.0), hyperopia (?2.00 D) was 0.4% (95% confidence interval, 0.00.7) and emmetropia with astigmatism (?0.75 D) was 0.7% (95% confidence interval, 0.21.2). Vision impairment due to myopia was associated with higher school grade and increased time spent reading and working on a computer. Conclusions Uncorrected refractive error, particularly myopia, among secondary school children in Vietnam is a major public health problem. School-based eye health initiative such as refractive error screening is warranted to reduce vision impairment. PMID:24299145

  17. Global Vision Impairment and Blindness Due to Uncorrected Refractive Error, 1990-2010.

    PubMed

    Naidoo, Kovin S; Leasher, Janet; Bourne, Rupert R; Flaxman, Seth R; Jonas, Jost B; Keeffe, Jill; Limburg, Hans; Pesudovs, Konrad; Price, Holly; White, Richard A; Wong, Tien Y; Taylor, Hugh R; Resnikoff, Serge

    2016-03-01

    : The purpose of this systematic review was to estimate worldwide the number of people with moderate and severe visual impairment (MSVI; presenting visual acuity <6/18, ?3/60) or blindness (presenting visual acuity <3/60) due to uncorrected refractive error (URE), to estimate trends in prevalence from 1990 to 2010, and to analyze regional differences. The review focuses on uncorrected refractive error which is now the most common cause of avoidable visual impairment globally. : The systematic review of 14,908 relevant manuscripts from 1990 to 2010 using Medline, Embase, and WHOLIS yielded 243 high-quality, population-based cross-sectional studies which informed a meta-analysis of trends by region. The results showed that in 2010, 6.8 million (95% confidence interval [CI]: 4.7-8.8 million) people were blind (7.9% increase from 1990) and 101.2 million (95% CI: 87.88-125.5 million) vision impaired due to URE (15% increase since 1990), while the global population increased by 30% (1990-2010). The all-age age-standardized prevalence of URE blindness decreased 33% from 0.2% (95% CI: 0.1-0.2%) in 1990 to 0.1% (95% CI: 0.1-0.1%) in 2010, whereas the prevalence of URE MSVI decreased 25% from 2.1% (95% CI: 1.6-2.4%) in 1990 to 1.5% (95% CI: 1.3-1.9%) in 2010. In 2010, URE contributed 20.9% (95% CI: 15.2-25.9%) of all blindness and 52.9% (95% CI: 47.2-57.3%) of all MSVI worldwide. The contribution of URE to all MSVI ranged from 44.2 to 48.1% in all regions except in South Asia which was at 65.4% (95% CI: 62-72%). : We conclude that in 2010, uncorrected refractive error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting a total of 108 million people or 1 in 90 persons. PMID:26905537

  18. In-home monitoring of older adults with vision impairment: exploring patients, caregivers and professionals views

    PubMed Central

    Larizza, Melanie Frances; Zukerman, Ingrid; Bohnert, Fabian; Busija, Lucy; Bentley, Sharon Ann; Russell, R Andrew; Rees, Gwyneth

    2014-01-01

    Objective To develop a conceptual framework for the design of an in-home monitoring system (IMS) based on the requirements of older adults with vision impairment (VI), informal caregivers and eye-care rehabilitation professionals. Materials and Methods Concept mapping, a mixed-methods statistical research tool, was used in the construction of the framework. Overall, 40 participants brainstormed or sorted and rated 83 statements concerning an IMS for older adults with VI. Multidimensional scaling and hierarchical cluster analysis were employed to construct the framework. A questionnaire yielded further insights into the views of a wider sample of older adults with VI (n=78) and caregivers (n=25) regarding IMS. Results Concept mapping revealed a nine-cluster model of IMS-related aspects including affordability, awareness of system capabilities, simplicity of installation, operation and maintenance, system integrity and reliability, fall detection and safe movement, user customization, user preferences regarding information delivery, and safety alerts for patients and caregivers. From the questionnaire, independence, safety and fall detection were the most commonly reported reasons for older adults and caregivers to accept an IMS. Concerns included cost, privacy, security of the information obtained through monitoring, system accuracy, and ease of use. Discussion Older adults with VI, caregivers and professionals are receptive to in-home monitoring, mainly for fall detection and safety monitoring, but have concerns that must be addressed when developing an IMS. Conclusion Our study provides a novel conceptual framework for the design of an IMS that will be maximally acceptable and beneficial to our ageing and vision-impaired population. PMID:23676244

  19. Epidemiological assessment of lens opacifications that impaired vision in patients injected with radium-224

    SciTech Connect

    Chmelevsky, D.; Mays, C.W.; Spiess, H.; Stefani, F.H.; Kellerer, A.M.

    1988-08-01

    The incidence of lens opacifications that impaired vision (cataract) was analyzed among 831 patients who were injected with known dosages of /sup 224/Ra in Germany shortly after World War II. The dependence of the incidence on dosage, i.e., injected activity per unit body weight, and on time after treatment was determined. The observations are equally consistent with proportionality of the incidence of cataract to the square of dosage or with a linear dependence beyond a threshold of 0.5 MBq/kg. The possibility of a linear dependence without threshold was strongly rejected (P less than 0.001). The analysis of temporal dependences yielded a component that was correlated with the injected amount of /sup 224/Ra and a component that was uncorrelated. The former was inferred by a maximum likelihood analysis to increase approximately as the square of the time after treatment. The component unrelated to the treatment was found to increase steeply with age and to become dominant within the collective of patients between age 50 and 60. The relative magnitudes of the two components were such that a fraction of 55 to 60% of the total of 58 cataracts had to be ascribed to the dose-related incidence. Impaired vision due to cataract was diagnosed before age 54 in 25 cases. In terms of injected activity per unit body weight no dependence of the sensitivity on age was found; specifically there was no indication of a faster occurrence of the treatment-related cataracts in patients treated at older ages.

  20. Object knowledge modulates colour appearance

    PubMed Central

    Witzel, Christoph; Valkova, Hanna; Hansen, Thorsten; Gegenfurtner, Karl R

    2011-01-01

    We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis. PMID:23145224

  1. Visual search performance of patients with vision impairment: Effect of JPEG image enhancement

    PubMed Central

    Luo, Gang; Satgunam, PremNandhini; Peli, Eli

    2012-01-01

    Purpose To measure natural image search performance in patients with central vision impairment. To evaluate the performance effect for a JPEG based image enhancement technique using the visual search task. Method 150 JPEG images were presented on a touch screen monitor in either an enhanced or original version to 19 patients (visual acuity 0.4 to 1.2 logMAR, 6/15 to 6/90, 20/50 to 20/300) and 7 normally sighted controls (visual acuity ?0.12 to 0.1 logMAR, 6/4.5 to 6/7.5, 20/15 to 20/25). Each image fell into one of three categories: faces, indoors, and collections. The enhancement was realized by moderately boosting a mid-range spatial frequency band in the discrete cosine transform (DCT) coefficients of the image luminance component. Participants pointed to an object in a picture that matched a given target displayed at the upper-left corner of the monitor. Search performance was quantified by the percentage of correct responses, the median search time of correct responses, and an integrated performance measure the area under the curve of cumulative correct response rate over search time. Results Patients were able to perform the search tasks but their performance was substantially worse than the controls. Search performances for the 3 image categories were significantly different (p?0.001) for all the participants, with searching for faces being the most difficult. When search time and correct response were analyzed separately, the effect of enhancement led to increase in one measure but decrease in another for many patients. Using the integrated performance, it was found that search performance declined with decrease in acuity (p=0.005). An improvement with enhancement was found mainly for the patients whose acuity ranged from 0.4 to 0.8 logMAR (6/15 to 6/38, 20/50 to 20/125). Enhancement conferred a small but significant improvement in integrated performance for indoor and collection images (p=0.025) in the patients. Conclusion Search performance for natural images can be measured in patients with impaired vision to evaluate the effect of image enhancement. Patients with moderate vision loss might benefit from the moderate level of enhancement used here. PMID:22540926

  2. Accessibility and Autonomy Preconditions to "Our" Inclusion: A Grounded Theory Study of the Experiences of Secondary Students with Vision Impairment

    ERIC Educational Resources Information Center

    Whitburn, Ben

    2014-01-01

    In this paper, I report core findings of a small-scale qualitative study that I conducted with a group of young people with vision impairment who attended an inclusive secondary school in the Australian state of Queensland. My objective was to capture their voiced experiences of their schooling through face-to-face interviews and to develop a

  3. For your eyes only: Harnessing human embryonic stem cell-derived retinal pigment epithelial cells to improve impaired vision

    PubMed Central

    Hu, Jim; He, Tong-Chuan; Li, Fei

    2015-01-01

    Vision loss or impairment resulting from the degeneration of the retinal pigment epithelium and photoreceptor death affects millions worldwide. Recent exciting results from clinical studies of small numbers of patients treated with human embryonic stem cell-derived retinal pigment epithelial cells may provide hope for affected individuals.

  4. Accessibility and Autonomy Preconditions to "Our" Inclusion: A Grounded Theory Study of the Experiences of Secondary Students with Vision Impairment

    ERIC Educational Resources Information Center

    Whitburn, Ben

    2014-01-01

    In this paper, I report core findings of a small-scale qualitative study that I conducted with a group of young people with vision impairment who attended an inclusive secondary school in the Australian state of Queensland. My objective was to capture their voiced experiences of their schooling through face-to-face interviews and to develop a…

  5. Candidate genes for colour and vision exhibit signals of selection across the pied flycatcher (Ficedula hypoleuca) breeding range

    PubMed Central

    Lehtonen, P K; Laaksonen, T; Artemyev, A V; Belskii, E; Berg, P R; Both, C; Buggiotti, L; Bure, S; Burgess, M D; Bushuev, A V; Krams, I; Moreno, J; Mgi, M; Nord, A; Potti, J; Ravussin, P-A; Sirki, P M; Stre, G-P; Winkel, W; Primmer, C R

    2012-01-01

    The role of natural selection in shaping adaptive trait differentiation in natural populations has long been recognized. Determining its molecular basis, however, remains a challenge. Here, we search for signals of selection in candidate genes for colour and its perception in a passerine bird. Pied flycatcher plumage varies geographically in both its structural and pigment-based properties. Both characteristics appear to be shaped by selection. A single-locus outlier test revealed 2 of 14 loci to show significantly elevated signals of divergence. The first of these, the follistatin gene, is expressed in the developing feather bud and is found in pathways with genes that determine the structure of feathers and may thus be important in generating variation in structural colouration. The second is a gene potentially underlying the ability to detect this variation: SWS1 opsin. These two loci were most differentiated in two Spanish pied flycatcher populations, which are also among the populations that have the highest UV reflectance. The follistatin and SWS1 opsin genes thus provide strong candidates for future investigations on the molecular basis of adaptively significant traits and their co-evolution. PMID:22027894

  6. The "voice" has it: screen reader adoption and switching behavior among vision impaired persons in India.

    PubMed

    McCarthy, Ted; Pal, Joyojeet; Cutrell, Edward

    2013-01-01

    We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, text-to-speech "voice" quality, particularly a "human-sounding voice" as one of the key features differentiating free/open source products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives--first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior. PMID:24620705

  7. Impairment of color vision among workers exposed to low concentrations of styrene.

    PubMed

    Chia, S E; Jeyaratnam, J; Ong, C N; Ng, T P; Lee, H S

    1994-10-01

    A field study was conducted among 21 male workers exposed to styrene of concentration below 30 ppm in a fiber-reinforced plastic boat manufacturing plant. Twenty-one male workers with similar age groupings, years of education, and social and occupational state served as referents. The mean end-of-shift urinary mandelic acid (MA) and phenylglycoxylic acid (PGA) for the exposed workers were 84 mg/g creatinine and 66 mg/g creatinine, respectively. The Lanthony D-15 Hue Desaturated Panel was used to evaluate color discrimination of the exposed and referent groups. The results of the test were expressed as total color difference score (TCDS). The exposed workers' mean TCDS (a higher score denotes poorer color discrimination ability) was significantly (p < 0.0006) higher than the referents'. Neurobehavioral tests were also conducted, using the World Health Organization's Neurobehavioral Core Test Battery (NCTB). All the results of the NCTB were poorer for the exposed than for the referents. However, significant differences were observed only for Digit Span, Digit Symbol, and Benton Visual Retention tests. These results suggest that low exposure to styrene could affect some psychometric performance and may impair color vision. PMID:7810546

  8. Colour constancy in insects.

    PubMed

    Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

    2014-06-01

    Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects. PMID:24647930

  9. Seeing in colour

    NASA Astrophysics Data System (ADS)

    Lotto, R. Beau; Clarke, Richard; Corney, David; Purves, Dale

    2011-03-01

    Understanding perception of colour is challenging because what we see is not always what is there, which is a phenomenon we call illusions. Here we review the nature of colour vision, and the problems facing most current models and explanations. Focusing on our recent research on humans, bees and computers, we describe a new, more ecologically based explanation that provides a clear framework for why we see what we do.

  10. Television, computer and portable display device use by people with central vision impairment

    PubMed Central

    Woods, Russell L; Satgunam, PremNandhini

    2011-01-01

    Purpose To survey the viewing experience (e.g. hours watched, difficulty) and viewing metrics (e.g. distance viewed, display size) for television (TV), computers and portable visual display devices for normally-sighted (NS) and visually impaired participants. This information may guide visual rehabilitation. Methods Survey was administered either in person or in a telephone interview on 223 participants of whom 104 had low vision (LV, worse than 6/18, age 22 to 90y, 54 males), and 94 were NS (visual acuity 6/9 or better, age 20 to 86y, 50 males). Depending on their situation, NS participants answered up to 38 questions and LV participants answered up to a further 10 questions. Results Many LV participants reported at least “some” difficulty watching TV (71/103), reported at least “often” having difficulty with computer displays (40/76) and extreme difficulty watching videos on handheld devices (11/16). The average daily TV viewing was slightly, but not significantly, higher for the LV participants (3.6h) than the NS (3.0h). Only 18% of LV participants used visual aids (all optical) to watch TV. Most LV participants obtained effective magnification from a reduced viewing distance for both TV and computer display. Younger LV participants also used a larger display when compared to older LV participants to obtain increased magnification. About half of the TV viewing time occurred in the absence of a companion for both the LV and the NS participants. The mean number of TVs at home reported by LV participants (2.2) was slightly but not significantly (p=0.09) higher than NS participants (2.0). LV participants were equally likely to have a computer but were significantly (p=0.004) less likely to access the internet (73/104) compared to NS participants (82/94). Most LV participants expressed an interest in image enhancing technology for TV viewing (67/104) and for computer use (50/74), if they used a computer. Conclusion In this study, both NS and LV participants had comparable video viewing habits. Most LV participants in our sample reported difficulty watching TV, and indicated an interest in assistive technology, such as image enhancement. As our participants reported that at least half their video viewing hours are spent alone and that there is usually more than one TV per household, this suggests that there are opportunities to use image enhancement on the TVs of LV viewers without interfering with the viewing experience of NS viewers. PMID:21410501

  11. "They Think They Know What's Best for Me": An Interpretative Phenomenological Analysis of the Experience of Inclusion and Support in High School for Vision-Impaired Students with Albinism

    ERIC Educational Resources Information Center

    Thurston, Mhairi

    2014-01-01

    The challenges of social inclusion and access to the curriculum facing students with visual impairment in schools are well documented. The refreshed UK Vision Strategy (2013) seeks to improve education for students with vision impairment. In order to do this, it is important to understand how students with visual impairment experience education.

  12. Applications of Colour Processing In Optical Inspection

    NASA Astrophysics Data System (ADS)

    Thomas, W. V.; Connolly, C.

    1986-11-01

    Humans are endowed with the facility to perceive colour. This not only provides an additional aesthetic dimension but also helps perform visual tasks efficiently. There are many occupations, including inspection, not open to those with defective colour vision. Todays machine vision systems are virtually all colour-blind. Yet there are applications where colour is intrinsic. Consider for example the inspection and grading of fruit, vegetables, biscuits and other food products. Consider also the widespread use of colour coding for wiring and components in the electrical and electronic industries. Automatic optical inspection of such things cannot be done without relating to colour. There are other applications where colour is not directly relevant but the additional information provided can help simplify and speed up the processing task. This paper reviews the nature of colour, relating the psychophysical aspects of colour perception and the physical properties of available sensors to the needs of an automatic inspection system. The theory of colour perception is based on the tri-stimulus theory which says that any colour may be matched using appropriate proportions of three primary colours. Although later experiments have suggested human colour perception is more complex, most electronic video sensors employ a three colour system. Usually the red, green and blue primary components are derived and may be used directly as sensory inputs to a vision system. However the primary representation of colour is not the most efficient means of encoding nor is it the most useful basis for interpretive processing. The R,G and B primary signals may be simply transformed into a new coordinate system where one of the axes represents true object colour or hue. Using this new colour space simplifies processing. These ideas are illustrated by an inspection example. The colour coded wires of a European power cable are identified to ensure that a power plug is safely wired. For this application a straightforward and reliable inspection system can only be produced using colour information.

  13. Extending Our Vision: Access to Inclusive Dance Education for People with Visual Impairment

    ERIC Educational Resources Information Center

    Seham, Jenny; Yeo, Anna J.

    2015-01-01

    Environmental, organizational and attitudinal obstacles continue to prevent people with vision loss from meaningfully engaging in dance education and performance. This article addresses the societal disabilities that handicap access to dance education for the blind. Although much of traditional dance instruction relies upon visual cuing and

  14. Changes in Quality of Life in Visually Impaired Patients after Low-Vision Rehabilitation

    ERIC Educational Resources Information Center

    Renieri, Giulia; Pitz, Susanne; Pfeiffer, Norbert; Beutel, Manfred E.; Zwerenz, Rudiger

    2013-01-01

    The objective of the study was to assess the impact of low-vision aids on quality of life. Interviews included a modified version of the National Eye Institute Visual Functioning Questionnaire (Modified German NEI VFQ-25), the Hospital Anxiety and Depression Scale, the Mini-Mental State Examination Blind, and Indicators of the Rehabilitation

  15. Changes in Quality of Life in Visually Impaired Patients after Low-Vision Rehabilitation

    ERIC Educational Resources Information Center

    Renieri, Giulia; Pitz, Susanne; Pfeiffer, Norbert; Beutel, Manfred E.; Zwerenz, Rudiger

    2013-01-01

    The objective of the study was to assess the impact of low-vision aids on quality of life. Interviews included a modified version of the National Eye Institute Visual Functioning Questionnaire (Modified German NEI VFQ-25), the Hospital Anxiety and Depression Scale, the Mini-Mental State Examination Blind, and Indicators of the Rehabilitation…

  16. The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

    ERIC Educational Resources Information Center

    Emmorey, Karen; Korpics, Franco; Petronio, Karen

    2009-01-01

    The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf

  17. The Use of Visual Feedback during Signing: Evidence from Signers with Impaired Vision

    ERIC Educational Resources Information Center

    Emmorey, Karen; Korpics, Franco; Petronio, Karen

    2009-01-01

    The role of visual feedback during the production of American Sign Language was investigated by comparing the size of signing space during conversations and narrative monologues for normally sighted signers, signers with tunnel vision due to Usher syndrome, and functionally blind signers. The interlocutor for all groups was a normally sighted deaf…

  18. Visual Impairment

    MedlinePLUS

    ... How Can I Help a Friend Who Cuts? Visual Impairment KidsHealth > For Teens > Visual Impairment Print A ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  19. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians. PMID:23664831

  20. Assistive obstacle detection and navigation devices for vision-impaired users.

    PubMed

    Ong, S K; Zhang, J; Nee, A Y C

    2013-09-01

    Quality of life for the visually impaired is an urgent worldwide issue that needs to be addressed. Obstacle detection is one of the most important navigation tasks for the visually impaired. In this research, a novel range sensor placement scheme is proposed in this paper for the development of obstacle detection devices. Based on this scheme, two prototypes have been developed targeting at different user groups. This paper discusses the design issues, functional modules and the evaluation tests carried out for both prototypes. Implications for Rehabilitation Visual impairment problem is becoming more severe due to the worldwide ageing population. Individuals with visual impairment require assistance from assistive devices in daily navigation tasks. Traditional assistive devices that assist navigation may have certain drawbacks, such as the limited sensing range of a white cane. Obstacle detection devices applying the range sensor technology can identify road conditions with a higher sensing range to notify the users of potential dangers in advance. PMID:23350879

  1. The Psychological Challenge of Late-Life Vision Impairment: Concepts, Findings, and Practical Implications

    PubMed Central

    Wahl, Hans-Werner

    2013-01-01

    The intention is to summarize the body of evidence speaking to the psychological challenges faced by visually impaired older adults, as well as their coping efforts. This evidence is substantiated by a rich set of concepts, theories, and empirical findings that have accumulated under the umbrella of age-related psychoophthalmology (APO). I introduce the field of APO and continue with a discussion of important concepts and theories for a better understanding of adaptational processes in visually impaired older adults. I then summarize the most relevant and most recent data from four areas: (1) everyday competence, (2) cognitive functioning, (3) social functioning, and (4) subjective well-being-related outcomes, depression, and adaptational processes. Thereafter, major insights related to the current state-of-the art psychosocial interventions with visuallyimpaired older adults are reviewed. I close with the need that the public health community should become more aware of and address the psychosocial needs of visually impaired older adults. PMID:23691277

  2. A grayscale pneumatic micro-valve for use in a reconfigurable tactile tablet for vision-impaired individuals

    NASA Astrophysics Data System (ADS)

    Schneider, Joseph Devin; Rebolledo-Mendez, Jovan David; McNamara, Shamus

    2015-01-01

    The design, fabrication, and characterization of a strained bilayer film for use in a micro-valve for a reconfigurable tactile tablet for vision-impaired individuals is presented. The bilayer film consists of a compressive and tensile layer to cause the film to coil and retract from the gas channel when the micro-valve is in the open position. A novel support structure that improves yield and controls the direction of coiling is demonstrated. An array of 225 strained bilayer films was designed and fabricated. Each strained bilayer film was able to be actuated individually with a voltage that ranged between 60 and 70?V. The relationship between the applied voltage and the percentage open of the micro-valve is found to be linear over an extended voltage range, enabling the reconfigurable tactile tablet to produce the equivalent of a grayscale image.

  3. Visualizing Without Vision at the Microscale: Students With Visual Impairments Explore Cells With Touch

    NASA Astrophysics Data System (ADS)

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-12-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This study explored the efficacy of new haptic (simulated tactile feedback and kinesthetics) instructional technology for teaching cell morphology and function to middle and high school students with visual impairments. The study examined students' prior experiences learning about the cell and cell functions in classroom instruction, as well as how haptic feedback technology impacted students' awareness of the 3-D nature of an animal cell, the morphology and function of cell organelles, and students' interest in the haptic technology as an instructional tool. Twenty-one students with visual impairment participated in the study. Students explored a tactile model of the cell with a haptic point probe that allowed them to feel the cell and its organelles. Results showed that students made significant gains in their ability to identify cell organelles and found the technology to be highly interesting as an instructional tool. The need for additional adaptive technology for students with visual impairments is discussed.

  4. Visualizing without Vision at the Microscale: Students with Visual Impairments Explore Cells with Touch

    ERIC Educational Resources Information Center

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-01-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This

  5. Visualizing without Vision at the Microscale: Students with Visual Impairments Explore Cells with Touch

    ERIC Educational Resources Information Center

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-01-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This…

  6. Vision Impairs the Abilities of Bats to Avoid Colliding with Stationary Obstacles

    PubMed Central

    Orbach, Dara N.; Fenton, Brock

    2010-01-01

    Background Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as distress calls of other bats, contributed to probabilities of collision. Methodology/Principal Findings To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions. Conclusions/Significance Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments. PMID:21085481

  7. Forming Effective Partnerships to Facilitate Inclusion of Students with Vision Impairments: Perceptions of a Regular Classroom Teacher and an Itinerant Teacher

    ERIC Educational Resources Information Center

    Sharma, Umesh; Moore, Dennis; Furlonger, Brett; King, Brian Smyth; Kaye, Linda; Constantinou, Olga

    2010-01-01

    This qualitative study reports on the perceptions of a regular classroom teacher and an itinerant teacher about the challenges they faced in including a student with vision impairment in regular school in New South Wales, Australia. Some of the common strategies employed by both these teachers to address these challenges are discussed. (Contains 1…

  8. Auditory localization and precedence effect: an exploratory study in infants and toddlers with visual impairment and normal vision.

    PubMed

    Hg, Mercedes X; Arias, Claudia; Tommasini, Fabin C; Ramos, Oscar A

    2014-09-01

    The precedence effect is a spatial hearing phenomenon implicated in sound localization on reverberant environments. It occurs when a pair of sounds, with a brief delay between them, is presented from different directions; listeners give greater perceptual weight to localization cues coming from the first-arriving sound, called lead, and suppress localization cues from the later-arriving reflection, called lag. Developmental studies with sighted infants show that the first responses to precedence effect stimuli are observed at 4-5 months of life. In this exploratory study, we use the minimum audible angle (MAA) paradigm in conjunction with the observer-based psychophysical procedure to test the ability of infants and toddlers, with visual impairment and normal vision, to discriminate changes in the azimuthal position of sounds configured under precedence effect conditions. The results indicated that similar and, in some conditions, higher performances were obtained by blind toddlers when compared to sighted children of similar age, and revealed that the observer-based psychophysical procedure is a valuable method to measure auditory localization acuity in infants and toddlers with visual impairment. The video records showed auditory orienting behaviors specific of the blind children group. PMID:24864055

  9. Can Hooke's Law and the Airy Disk First Zero Radius Formulation Predict That Education and Work Environment Visual Task Excesses Lead to Vision Impairment?

    NASA Astrophysics Data System (ADS)

    McLeod, Douglas M.; McLeod, Roger D.

    2002-10-01

    DMM found that a distant, single church steeple, which appeared "twin-like" after extended studying episodes, could then be brought into correct visual register by a conscious effort. Similar anecdotal events are repeatable by attentive students or workers in the early stages of educationally or work environmentally induced repetitive vision impairment. RDM proposes that his model for vision and its repair utilizes sequentially applied vision improvement stages that are the equivalent of DMM's experience. Such visual events involve feedback signals generated during the crystalline lens's minor dioptric oscillations that are generated by the blinking reflex, empowered by the Airy radius proportional to wavelength times focal length divided by pupil aperture. This implies some conscious control of feedback mechanisms, which can self-regulate vision protecting processes. Continued visual effort under duress invokes Hooke's "stress proportional to strain." Exceeding extrinsic eye muscles' elastic limits overrides spontaneous feedback repair mechanisms.

  10. Integrated vision-based robotic arm interface for operators with upper limb mobility impairments.

    PubMed

    Jiang, Hairong; Wachs, Juan P; Duerstock, Bradley S

    2013-06-01

    An integrated, computer vision-based system was developed to operate a commercial wheelchair-mounted robotic manipulator (WMRM). In this paper, a gesture recognition interface system developed specifically for individuals with upper-level spinal cord injuries (SCIs) was combined with object tracking and face recognition systems to be an efficient, hands-free WMRM controller. In this test system, two Kinect cameras were used synergistically to perform a variety of simple object retrieval tasks. One camera was used to interpret the hand gestures to send as commands to control the WMRM and locate the operator's face for object positioning. The other sensor was used to automatically recognize different daily living objects for test subjects to select. The gesture recognition interface incorporated hand detection, tracking and recognition algorithms to obtain a high recognition accuracy of 97.5% for an eight-gesture lexicon. An object recognition module employing Speeded Up Robust Features (SURF) algorithm was performed and recognition results were sent as a command for "coarse positioning" of the robotic arm near the selected daily living object. Automatic face detection was also provided as a shortcut for the subjects to position the objects to the face by using a WMRM. Completion time tasks were conducted to compare manual (gestures only) and semi-manual (gestures, automatic face detection and object recognition) WMRM control modes. The use of automatic face and object detection significantly increased the completion times for retrieving a variety of daily living objects. PMID:24187264

  11. Pentachromatic colour spaces

    NASA Astrophysics Data System (ADS)

    Restrepo, Alfredo

    2015-03-01

    We generalise previous results to dimension 5. We exploit the geometric properties of the 5-hypercube [0, 1]5 in order to give a mathematical model for colour vision in the case of 5 photoreceptor types and for the corresponding additive colour combination with five primary lights. Five photoreceptors or five types of camera pixel filters with responses normalised to the interval [0, 1] give rise to a 5 dimensional hypercube [0, 1]5 of combined responses (colours). As previously done, for the trichromatic and tetrachromatic cases, we identify an equatorial PL 3- sphere in the PL 4-sphere boundary ?[0, 1]5 of the hypercube. This equatorial sphere is the set of hues of the chromatic colour points in the hypercube. The remaining attributes of luminance and chromatic saturation are given by the midrange and range of the colour coordinates. From the 5-cube we go to a polytopal hexcone type space, to a double-cone type space and to a round Runge space.

  12. Colour detection thresholds in faces and colour patches.

    PubMed

    Tan, Kok Wei; Stephen, Ian D

    2013-01-01

    Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status. PMID:24344549

  13. Applying colour science in colour design

    NASA Astrophysics Data System (ADS)

    Luo, Ming Ronnier

    2006-06-01

    Although colour science has been widely used in a variety of industries over the years, it has not been fully explored in the field of product design. This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling. By integrating these advanced colour technologies together with modern colour imaging devices such as display, camera, scanner and printer, some computer systems have been recently developed to assist designers for designing colour palettes through colour selection by means of a number of widely used colour order systems, for creating harmonised colour schemes via a categorical colour system, for generating emotion colours using various colour emotional scales and for facilitating colour naming via a colour-name library. All systems are also capable of providing accurate colour representation on displays and output to different imaging devices such as printers.

  14. Monitor, a vibrotactile aid for environmental perception: a field evaluation by four people with severe hearing and vision impairment.

    PubMed

    Ranjbar, Parivash; Stenstrm, Ingeborg

    2013-01-01

    Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44-54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%-97% and 58%-95% with the directional microphone. The corresponding values in traffic were 29%-100% and 65%-100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds. PMID:23861651

  15. Monitor, a Vibrotactile Aid for Environmental Perception: A Field Evaluation by Four People with Severe Hearing and Vision Impairment

    PubMed Central

    Stenström, Ingeborg

    2013-01-01

    Monitor is a portable vibrotactile aid to improve the ability of people with severe hearing impairment or deafblindness to detect, identify, and recognize the direction of sound-producing events. It transforms and adapts sounds to the frequency sensitivity range of the skin. The aid was evaluated in the field. Four females (44–54 years) with Usher Syndrome I (three with tunnel vision and one with only light perception) tested the aid at home and in traffic in three different field studies: without Monitor, with Monitor with an omnidirectional microphone, and with Monitor with a directional microphone. The tests were video-documented, and the two field studies with Monitor were initiated after five weeks of training. The detection scores with omnidirectional and directional microphones were 100% for three participants and above 57% for one, both in their home and traffic environments. In the home environment the identification scores with the omnidirectional microphone were 70%–97% and 58%–95% with the directional microphone. The corresponding values in traffic were 29%–100% and 65%–100%, respectively. Their direction perception was improved to some extent by both microphones. Monitor improved the ability of people with deafblindness to detect, identify, and recognize the direction of events producing sounds. PMID:23861651

  16. The “voice” has it: screen reader adoption and switching behavior among vision impaired persons in India

    PubMed Central

    Pal, Joyojeet; Cutrell, Edward

    2013-01-01

    We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, TTS “voice” quality, particularly a “human-sounding voice” as one of the key features differentiating free/open source (FOSS) products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives – first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior. PMID:24620705

  17. Cav1.4 IT mouse as model for vision impairment in human congenital stationary night blindness type 2

    PubMed Central

    Knoflach, Dagmar; Kerov, Vasily; Sartori, Simone B; Obermair, Gerald J; Schmuckermair, Claudia; Liu, Xiaoni; Sothilingam, Vithiyanjali; Garrido, Marina Garcia; Baker, Sheila A; Glsmann, Martin; Schicker, Klaus; Seeliger, Mathias; Lee, Amy; Koschak, Alexandra

    2013-01-01

    Mutations in the CACNA1F gene encoding the Cav1.4 Ca2+ channel are associated with X-linked congenital stationary night blindness type 2 (CSNB2). Despite the increasing knowledge about the functional behavior of mutated channels in heterologous systems, the pathophysiological mechanisms that result in vision impairment remain to be elucidated. This work provides a thorough functional characterization of the novel IT mouse line that harbors the gain-of-function mutation I745T reported in a New Zealand CSNB2 family.1 Electroretinographic recordings in IT mice permitted a direct comparison with human data. Our data supported the hypothesis that a hyperpolarizing shift in the voltage-dependence of channel activationas seen in the IT gain-of-function mutant2may reduce the dynamic range of photoreceptor activity. Morphologically, the retinal outer nuclear layer in adult IT mutants was reduced in size and cone outer segments appeared shorter. The organization of the outer plexiform layer was disrupted, and synaptic structures of photoreceptors had a variable, partly immature, appearance. The associated visual deficiency was substantiated in behavioral paradigms. The IT mouse line serves as a specific model for the functional phenotype of human CSNB2 patients with gain-of-function mutations and may help to further understand the dysfunction in CSNB. PMID:24051672

  18. Hardware Implementation of a Spline-Based Genetic Algorithm for Embedded Stereo Vision Sensor Providing Real-Time Visual Guidance to the Visually Impaired

    NASA Astrophysics Data System (ADS)

    Lee, Dah-Jye; Anderson, Jonathan D.; Archibald, James K.

    2008-12-01

    Many image and signal processing techniques have been applied to medical and health care applications in recent years. In this paper, we present a robust signal processing approach that can be used to solve the correspondence problem for an embedded stereo vision sensor to provide real-time visual guidance to the visually impaired. This approach is based on our new one-dimensional (1D) spline-based genetic algorithm to match signals. The algorithm processes image data lines as 1D signals to generate a dense disparity map, from which 3D information can be extracted. With recent advances in electronics technology, this 1D signal matching technique can be implemented and executed in parallel in hardware such as field-programmable gate arrays (FPGAs) to provide real-time feedback about the environment to the user. In order to complement (not replace) traditional aids for the visually impaired such as canes and Seeing Eyes dogs, vision systems that provide guidance to the visually impaired must be affordable, easy to use, compact, and free from attributes that are awkward or embarrassing to the user. "Seeing Eye Glasses," an embedded stereo vision system utilizing our new algorithm, meets all these requirements.

  19. Pseudoisochromatic test plate colour representation dependence on printing technology

    NASA Astrophysics Data System (ADS)

    Luse, K.; Fomins, S.; Ozolinsh, M.

    2012-08-01

    The aim of the study is to determine best printing technology for creation of colour vision deficiency tests. Valid tests for protanopia and deuteranopia were created from perceived colour matching experiments from printed colour samples by colour deficient individuals. Calibrated EpsonStylus Pro 7800 printer for ink prints and Noritsu HD 3701 digital printer for photographic prints were used. Multispectral imagery (by tunable liquid crystal filters system CRI Nuance Vis 07) data analysis show that in case of ink prints, the measured pixel colour coordinate dispersion (in the CIExy colour diagram) of similar colour arrays is smaller than in case of photographic printing. The print quality in terms of colour coordinate dispersion for printing methods used is much higher than in case of commercially available colour vision deficiency tests.

  20. Blood groups, ABH saliva secretion and colour vision deficiency in Hindu castes and religious groups of West Godavari, Andhra Pradesh, India.

    PubMed

    Vijayalakshmi, M; Naidu, J M; Suryanarayana, B

    1994-12-01

    The distribution of A1A2B0 and Rh(D) blood groups, ABH saliva secretion and red-green colour blindness among fourteen Hindu caste groups, besides Christian and Muslim populations of West Godavari District, Andhra Pradesh, India, is reported. All the Hindu castes except Brahmin, Kshatriya and Reddy exhibit relatively higher frequency of group B over group A. The subtyping of group A reveals that group A2 records an incidence ranging from 0.98% to 7.78%. The interpopulation chi-square tests for A1A2B0 blood group distribution indicate significant variation between several Hindu castes. The Vysya, Reddy and Adi Andhra castes not only differ from each other but also register significant variation from a majority of other populations. In the ABH saliva secretion also Vysya deviate from all other populations by recording the highest incidence (37.70%) of non-secretors, while the lowest frequency (19.98%) was observed among Kamma. The Rh(D) negative blood group is observed in all Hindu castes and religious groups with an incidence ranging from 1.04% in Vysya to 8.11% in Kamma. All the sixteen populations investigated exhibit prevalence of red-green colour blindness with a relatively higher frequency of deutan type over protan. PMID:7840536

  1. Impairments to Vision

    MedlinePLUS

    ... in both eyes. Simulations based on Ohio LIONS Eye Research Foundation (OLERF) images Home , Contact Us US Dept of Commerce National Oceanic and Atmospheric Administration National Weather Service 1325 East-West Highway Silver ...

  2. Present Vision--Future Vision.

    ERIC Educational Resources Information Center

    Fitterman, L. Jeffrey

    This paper addresses issues of current and future technology use for and by individuals with visual impairments and blindness in Florida. Present technology applications used in vision programs in Florida are individually described, including video enlarging, speech output, large inkprint, braille print, paperless braille, and tactual output…

  3. X-linked cone dystrophy and colour vision deficiency arising from a missense mutation in a hybrid L/M cone opsin gene

    PubMed Central

    McClements, Michelle; Davies, Wayne I L; Michaelides, Michel; Carroll, Joseph; Rha, Jungate; Mollon, John D; Neitz, Maureen; MacLaren, Robert E; Moore, Anthony T; Hunt, David M

    2013-01-01

    In this report, we describe a male subject who presents with a complex phenotype of myopia associated with cone dysfunction and a protan vision deficiency. Retinal imaging demonstrates extensive cone disruption, including the presence of non-waveguiding cones, an overall thinning of the retina, and an irregular mottled appearance of the hyper reflective band associated with the inner segment ellipsoid portion of the photoreceptor. Mutation screening revealed a novel p.Glu41Lys missense mutation in a hybrid L/M opsin gene. Spectral analysis shows that the mutant opsin fails to form a pigment in vitro and fails to be trafficked to the cell membrane in transfected Neuro2a cells. Extensive sequence and quantitative PCR analysis identifies this mutant gene as the only gene present in the affected subject’s L/M opsin gene array, yet the presence of protanopia indicates that the mutant opsin must retain some activity in vivo. To account for this apparent contradiction, we propose that a limited amount of functional pigment is formed within the normal cellular environment of the intact photoreceptor, and that this requires the presence of chaperone proteins that promote stability and normal folding of the mutant protein. PMID:23337435

  4. Low Vision Training in Sweden.

    ERIC Educational Resources Information Center

    Inde, Krister

    1978-01-01

    The article describes the team work approach used in Sweden to provide services to the four main categories of visual impairment: central scotoma, nystagmus, loss of peripheral vision while retaining central vision, and amblyopia. (Author/PHR)

  5. In the Palm of Your Hand: A Vision of the Future of Technology for People with Visual Impairments.

    ERIC Educational Resources Information Center

    Fruchterman, James R.

    2003-01-01

    This article discusses future directions for wireless cell phones, including personal computer capabilities, multiple input and output modalities, and open source platforms, and the benefits for people with visual impairments. The use of cell phones for increased accessibility of the Internet and for electronic books is also discussed. (Contains

  6. Holmes and Horrax (1919) revisited: impaired binocular fusion as a cause of "flat vision" after right parietal brain damage - a case study.

    PubMed

    Schaadt, Anna-Katharina; Brandt, Stephan A; Kraft, Antje; Kerkhoff, Georg

    2015-03-01

    The complete loss of binocular depth perception ("flat vision") was first thoroughly described by Holmes and Horrax (1919), and has been occasionally reported thereafter in patients with bilateral posterior-parietal lesions. Though partial spontaneous recovery occurred in some cases, the precise cause(s) of this condition remained obscure for almost a century. Here, we describe a unique patient (EH) with a large right-sided occipito-parietal hemorrhage showing a complete loss of visual depth perception for several months post-stroke. EH could well simultaneously describe multiple visual objects - hence did not show simultanagnosia - but at the same time was completely unable to estimate their distance from him. In every 3-D visual scene objects appeared equidistant to him, thus experiencing a total loss of depth perception ("flat vision"). Neurovisual assessments revealed normal functions of the eyes. EH showed bilateral lower field loss and a severely impaired binocular convergent fusion, but preserved stereopsis. Perceptual re-training of binocular fusion resulted in a progressive and finally complete recovery of objective binocular fusion values and subjective binocular depth perception in a far-to-near-space, gradient-like manner. In parallel, visual depth estimation of relative distances improved, whereas stereopsis remained unchanged. Our results show that a complete loss of 3-D depth perception can result from an isolated impairment in binocular fusion. On a neuroanatomical level, this connection could be explained by a selective lesion of area V6/V6A in the medial occipito-parietal cortex that has been associated with the integration of visual space coordinates and sustained eye-positions into a cyclopean visual 3-D percept. PMID:25619849

  7. Spectral sensitivity of a colour changing spider.

    PubMed

    Defrize, Jrmy; Lazzari, Claudio R; Warrant, Eric J; Casas, Jrme

    2011-04-01

    Vision plays a paramount role in some spider families such as the Salticidae, Lycosidae and Thomisidae, as it is involved in prey hunting, orientation or choice of substrate. In the thomisid Misumena vatia, for which the substrate colour affects the body colour, vision seems to mediate morphological colour changes. However, nothing is known about which component of visual signals from the substrate might be perceived, nor whether M. vatia possesses the physiological basis for colour vision. The aim of this study is thus to investigate the vision of this spider species by measuring the spectral sensitivities of the different pairs of eyes using electrophysiological methods. Extra- and intracellular electrophysiological recordings combined with selective adaptation revealed the presence of two classes of photoreceptor cells, one sensitive in the UV region of the spectrum (around 340 nm) and one sensitive in the green (around 520 nm) regions in the four pairs of eyes. We conclude that M. vatia possesses the physiological potential to perceive both chromatic and achromatic components of the environment. PMID:21300067

  8. Light Vision Color

    NASA Astrophysics Data System (ADS)

    Valberg, Arne

    2005-04-01

    Light Vision Color takes a well-balanced, interdisciplinary approach to our most important sensory system. The book successfully combines basics in vision sciences with recent developments from different areas such as neuroscience, biophysics, sensory psychology and philosophy. Originally published in 1998 this edition has been extensively revised and updated to include new chapters on clinical problems and eye diseases, low vision rehabilitation and the basic molecular biology and genetics of colour vision. Takes a broad interdisciplinary approach combining basics in vision sciences with the most recent developments in the area Includes an extensive list of technical terms and explanations to encourage student understanding Successfully brings together the most important areas of the subject in to one volume

  9. Vision in Alzheimer's Disease.

    ERIC Educational Resources Information Center

    Cronin-Golomb, Alice

    1995-01-01

    In order to assess vision in Alzheimer's disease, gerontologists must use tests that make minimal cognitive demands on the subject. Using such tests revealed a pattern of deficits in color discrimination, stereoacuity, contrast sensitivity, and backward masking. Impaired vision predicts deficient performance on numerous tests of cognition. (JPS)

  10. The unsuitability of html-based colour charts for estimating animal colours a comment on Berggren and Meril (2004)

    PubMed Central

    Stevens, Martin; Cuthill, Innes C

    2005-01-01

    Background A variety of techniques are used to study the colours of animal signals, including the use of visual matching to colour charts. This paper aims to highlight why they are generally an unsatisfactory tool for the measurement and classification of animal colours and why colour codes based on HTML (really RGB) standards, as advocated in a recent paper, are particularly inappropriate. There are many theoretical arguments against the use of colour charts, not least that human colour vision differs markedly from that of most other animals. However, the focus of this paper is the concern that, even when applied to humans, there is no simple 1:1 mapping from an RGB colour space to the perceived colours in a chart (the results are both printer- and illumination-dependent). We support our criticisms with data from colour matching experiments with humans, involving self-made, printed colour charts. Results Colour matching experiments with printed charts involving 11 subjects showed that the choices made by individuals were significantly different between charts that had exactly the same RGB values, but were produced from different printers. Furthermore, individual matches tended to vary under different lighting conditions. Spectrophotometry of the colour charts showed that the reflectance spectra of the charts varied greatly between printers and that equal steps in RGB space were often far from equal in terms of reflectance on the printed charts. Conclusion In addition to outlining theoretical criticisms of the use of colour charts, our empirical results show that: individuals vary in their perception of colours, that different printers produce strikingly different results when reproducing what should be the same chart, and that the characteristics of the light irradiating the surface do affect colour perception. Therefore, we urge great caution in the use of colour charts to study animal colour signals. They should be used only as a last resort and in full knowledge of their limitations, with specially produced charts made to high industry standards. PMID:16131394

  11. Why do seals have cones? Behavioural evidence for colour-blindness in harbour seals.

    PubMed

    Scholtyssek, Christine; Kelber, Almut; Dehnhardt, Guido

    2015-03-01

    All seals and cetaceans have lost at least one of two ancestral cone classes and should therefore be colour-blind. Nevertheless, earlier studies showed that these marine mammals can discriminate colours and a colour vision mechanism has been proposed which contrasts signals from cones and rods. However, these earlier studies underestimated the brightness discrimination abilities of these animals, so that they could have discriminated colours using brightness only. Using a psychophysical discrimination experiment, we showed that a harbour seal can solve a colour discrimination task by means of brightness discrimination alone. Performing a series of experiments in which two harbour seals had to discriminate the brightness of colours, we also found strong evidence for purely scotopic (rod-based) vision at light levels that lead to mesopic (rod-cone-based) vision in other mammals. This finding speaks against rod-cone-based colour vision in harbour seals. To test for colour-blindness, we used a cognitive approach involving a harbour seal trained to use a concept of same and different. We tested this seal with pairs of isoluminant stimuli that were either same or different in colour. If the seal had perceived colour, it would have responded to colour differences between stimuli. However, the seal responded with "same", providing strong evidence for colour-blindness. PMID:25452008

  12. Rethinking Colour Constancy

    PubMed Central

    Logvinenko, Alexander D.; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching’s effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions—metamer mismatching and colour constancy—must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy’s false premise that colour is an intrinsic attribute of an object. PMID:26356217

  13. Early-onset Alzheimers and cortical vision impairment in a woman with valosin-containing protein disease associated with 2 APOE ?4/APOE ?4 genotype.

    PubMed

    Shamirian, Sharis; Nalbandian, Angle; Khare, Manaswitha; Castellani, Rudolph; Kim, Ronald; Kimonis, Virginia E

    2015-01-01

    Hereditary inclusion body myopathy is a heterogeneous group of disorders characterized by rimmed vacuoles and by the presence of filamentous cytoplasmic and intranuclear inclusions. Inclusion body myopathy with Paget disease of bone and frontotemporal dementia is a progressive autosomal dominant disorder associated with a mutation in valosin-containing protein (VCP) with typical onset of symptoms in the 30s. APOE [Latin Small Letter Open E]4 is a major risk factor for late-onset Alzheimer disease, a progressive neurodegenerative disorder that affects memory, thinking, behavior, and emotion as a result of the excessive buildup and decreased clearance of ?-amyloid proteins resulting in the appearance of neuritic plaques and neurofibrillary tangles. In conclusion, we report a unique patient with an APOE [Latin Small Letter Open E]4/APOE [Latin Small Letter Open E]4 genotype and atypical VCP disease associated with early Alzheimer disease and severe vision impairment. Future studies will elucidate the interaction of VCP mutations and APOE [Latin Small Letter Open E]4 alleles in understanding common mechanisms in AD and VCP disease. PMID:23715207

  14. Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population

    PubMed Central

    Mandas, Antonella; Mereu, Rosa Maria; Catte, Olga; Saba, Antonio; Serchisu, Luca; Costaggiu, Diego; Peiretti, Enrico; Caminiti, Giulia; Vinci, Michela; Casu, Maura; Piludu, Stefania; Fossarello, Maurizio; Manconi, Paolo Emilio; Dessí, Sandra

    2014-01-01

    Neurological disorders (Alzheimer’s disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65 years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer’s disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer’s disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer’s disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision disorders but with dementia, and, similarly, none in subjects with vision disorders but without dementia. Overall, these results confirm the general impression so far; namely, that macular degeneration may contribute to cognitive disorders (Alzheimer’s disease in particular). In addition, they also suggest that, while statin and aspirin use may undoubtedly have some protective effects, they do not appear to be magic pills against the development of cognitive impairment or vision disorders in the elderly. PMID:25426067

  15. Cognitive Impairment and Age-Related Vision Disorders: Their Possible Relationship and the Evaluation of the Use of Aspirin and Statins in a 65 Years-and-Over Sardinian Population.

    PubMed

    Mandas, Antonella; Mereu, Rosa Maria; Catte, Olga; Saba, Antonio; Serchisu, Luca; Costaggiu, Diego; Peiretti, Enrico; Caminiti, Giulia; Vinci, Michela; Casu, Maura; Piludu, Stefania; Fossarello, Maurizio; Manconi, Paolo Emilio; Dess, Sandra

    2014-01-01

    Neurological disorders (Alzheimer's disease, vascular and mixed dementia) and visual loss (cataract, age-related macular degeneration, glaucoma, and diabetic retinopathy) are among the most common conditions that afflict people of at least 65?years of age. An increasing body of evidence is emerging, which demonstrates that memory and vision impairment are closely, significantly, and positively linked and that statins and aspirin may lessen the risk of developing age-related visual and neurological problems. However, clinical studies have produced contradictory results. Thus, the intent of the present study was to reliably establish whether a relationship exist between various types of dementia and age-related vision disorders, and to establish whether statins and aspirin may or may not have beneficial effects on these two types of disorders. We found that participants with dementia and/or vision problems were more likely to be depressed and displayed worse functional ability in basic and instrumental activities of daily living than controls. Mini mental state examination scores were significantly lower in patients with vision disorders compared to subjects without vision disorders. A closer association with macular degeneration was found in subjects with Alzheimer's disease than in subjects without dementia or with vascular dementia, mixed dementia, or other types of age-related vision disorders. When we considered the associations between different types of dementia and vision disorders and the use of statins and aspirin, we found a significant positive association between Alzheimer's disease and statins on their own or in combination with aspirin, indicating that these two drugs do not appear to reduce the risk of Alzheimer's disease or improve its clinical evolution and may, on the contrary, favor its development. No significant association in statin use alone, aspirin use alone, or the combination of these was found in subjects without vision disorders but with dementia, and, similarly, none in subjects with vision disorders but without dementia. Overall, these results confirm the general impression so far; namely, that macular degeneration may contribute to cognitive disorders (Alzheimer's disease in particular). In addition, they also suggest that, while statin and aspirin use may undoubtedly have some protective effects, they do not appear to be magic pills against the development of cognitive impairment or vision disorders in the elderly. PMID:25426067

  16. Aging and Vision

    PubMed Central

    Owsley, Cynthia

    2010-01-01

    Given the increasing size of the older adult population in many countries, there is a pressing need to identify the nature of aging-related vision impairments, their underlying mechanisms, and how they impact older adults’ performance of everyday visual tasks. The results of this research can then be used to develop and evaluate interventions to slow or reverse aging-related declines in vision, thereby improving quality of life. Here we summarize salient developments in research on aging and vision over the past 25 years, focusing on spatial contrast sensitivity, vision under low luminance, temporal sensitivity and motion perception, and visual processing speed. PMID:20974168

  17. Vision Deficits in Adults with Down Syndrome

    PubMed Central

    Krinsky-McHale, Sharon J.; Silverman, Wayne; Gordon, James; Devenny, Darlynne A.; Oley, Nancy; Abramov, Israel

    2013-01-01

    Background In individuals with Down syndrome virtually all structures of the eye have some abnormality which likely diminishes vision. We examined basic vision functions in adults with Down syndrome. Materials and Methods Participants completed a battery of psychophysical tests which probed a comprehensive array of visual functions. The performance of adults with Down syndrome was compared to younger and older adults without intellectual disability. Results Adults with Down syndrome had significant vision deficits; reduced sensitivity across spatial frequencies and temporal modulation rates, reduced stereopsis, impaired vernier acuity, and anomalies in colour discrimination. The pattern of deficits observed was similar to those seen by researchers examining adults with Alzheimer’s disease. Conclusions Our findings suggest that a common mechanism may be responsible for the pattern of deficits observed, possibly the presence of Alzheimer’s disease neuropathology in the visual association cortex. We also showed that individuals with mild to moderate intellectual disability are capable of participating in studies employing state-of-the-art psychophysical procedures. This has wider implications in terms of their ability to participate in research that use similar techniques. PMID:23784802

  18. Seasonal Changes in Colour: A Comparison of Structural, Melanin- and Carotenoid-Based Plumage Colours

    PubMed Central

    Delhey, Kaspar; Burger, Claudia; Fiedler, Wolfgang; Peters, Anne

    2010-01-01

    Background Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult, although whether this affects signalling has not been sufficiently assessed. Methodology/Principal Findings We studied changes in coloration after moult in four passerine birds (robin, Erithacus rubecula; blackbird, Turdus merula; blue tit, Cyanistes caeruleus; and great tit, Parus major) displaying various coloration types (melanin-, carotenoid-based and structural). Birds were caught regularly during three years to measure plumage reflectance. We used models of avian colour vision to derive two variables, one describing chromatic and the other achromatic variation over the year that can be compared in magnitude among different colour types. All studied plumage patches but one (yellow breast of the blue tit) showed significant chromatic changes over the year, although these were smaller than for a typical dynamic trait (bill colour). Overall, structural colours showed a reduction in relative reflectance at shorter wavelengths, carotenoid-based colours the opposite pattern, while no general pattern was found for melanin-based colours. Achromatic changes were also common, but there were no consistent patterns of change for the different types of colours. Conclusions/Significance Changes of plumage coloration independent of moult are probably widespread; they should be perceivable by birds and have the potential to affect colour signalling. PMID:20644723

  19. Topographic Mapping of Residual Vision by Computer

    ERIC Educational Resources Information Center

    MacKeben, Manfred

    2008-01-01

    Many persons with low vision have diseases that damage the retina only in selected areas, which can lead to scotomas (blind spots) in perception. The most frequent of these diseases is age-related macular degeneration (AMD), in which foveal vision is often impaired by a central scotoma that impairs vision of fine detail and causes problems with

  20. Does Colour Preference Have a Role in Colour Term Acquisition?

    ERIC Educational Resources Information Center

    Pitchford, Nicola J.; Davis, Emma E.; Scerif, Gaia

    2009-01-01

    A developmental association exists between colour preference and emerging colour term acquisition in young children. Colour preference might influence colour term acquisition by directing attention towards or away from a particular colour, making it more or less memorable. To investigate the role that colour preference may have in the acquisition

  1. Colour and lighting in hospital design

    NASA Astrophysics Data System (ADS)

    Dalke, Hilary; Little, Jenny; Niemann, Elga; Camgoz, Nilgun; Steadman, Guillaume; Hill, Sarah; Stott, Laura

    2006-06-01

    Little information or guidance has been available to assist the development of a hospital's visual environment. A report on lighting and colour design schemes, accessible to non professionals with responsibility for refurbishment strategies, was required by NHS Estates. Firstly, 20 hospitals were audited to establish a picture of current practice and to identify key issues where colour design could broadly enhance the environment for patients, staff and visitors. Critical areas were outlined in this report, where colour design can be utilised and applied, for the benefit of all users, from ambience to essential legal requirements such as colour contrast for the visually impaired. Provision of staff relaxation rooms that are different in terms of colour and lux levels from immediate work spaces, or thoughtfully designed areas for patients awaiting intensive treatment, have been shown to have some beneficial effects on a sense of well being. Colour and design have not been established as a definite cure for sickness and ill health, but certainly monotony and poor conditions in premises that have not been refurbished with any care, have had a detrimental affect on recovery rates and staff morale. The realisation that a well balanced and attractive environment is of major importance to patients' health is, in no way new; Florence Nightingale observed that 'a variety of form and brilliance of colour in the objects presented to patients are an actual means of recovery'.

  2. Trends in the Prevalence of Autism Spectrum Disorder, Cerebral Palsy, Hearing Loss, Intellectual Disability, and Vision Impairment, Metropolitan Atlanta, 1991–2010

    PubMed Central

    Van Naarden Braun, Kim; Christensen, Deborah; Doernberg, Nancy; Schieve, Laura; Rice, Catherine; Wiggins, Lisa; Schendel, Diana; Yeargin-Allsopp, Marshalyn

    2015-01-01

    This study examined the prevalence and characteristics of autism spectrum disorder (ASD), cerebral palsy (CP), hearing loss (HL), intellectual disability (ID), and vision impairment (VI) over a 15–20 year time period, with specific focus on concurrent changes in ASD and ID prevalence. We used data from a population-based developmental disabilities surveillance program for 8-year-olds in metropolitan Atlanta. From 1991–2010, prevalence estimates of ID and HL were stable with slight increases in VI prevalence. CP prevalence was constant from 1993–2010. The average annual increase in ASD prevalence was 9.3% per year from 1996–2010, with a 269% increase from 4.2 per 1,000 in 1996 to 15.5 per 1,000 in 2010. From 2000–2010, the prevalence of ID without ASD was stable; during the same time, the prevalence of ASD with and without co-occurring ID increased by an average of 6.6% and 9.6% per year, respectively. ASD prevalence increases were found among both males and females, and among nearly all racial/ethnic subgroups and levels of intellectual ability. Average annual prevalence estimates from 1991–2010 underscore the significant community resources needed to provide early intervention and ongoing supports for children with ID (13.0 per 1,000), CP, (3.5 per 1,000), HL (1.4 per 1,000) and VI (1.3 in 1,000), with a growing urgency for children with ASD. PMID:25923140

  3. Rockpool Gobies Change Colour for Camouflage

    PubMed Central

    Stevens, Martin; Lown, Alice E.; Denton, Alexander M.

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  4. Rockpool gobies change colour for camouflage.

    PubMed

    Stevens, Martin; Lown, Alice E; Denton, Alexander M

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  5. Optimality of the basic colour categories for classification

    PubMed Central

    Griffin, Lewis D

    2005-01-01

    Categorization of colour has been widely studied as a window into human language and cognition, and quite separately has been used pragmatically in image-database retrieval systems. This suggests the hypothesis that the best category system for pragmatic purposes coincides with human categories (i.e. the basic colours). We have tested this hypothesis by assessing the performance of different category systems in a machine-vision task. The task was the identification of the odd-one-out from triples of images obtained using a web-based image-search service. In each triple, two of the images had been retrieved using the same search term, the other a different term. The terms were simple concrete nouns. The results were as follows: (i) the odd-one-out task can be performed better than chance using colour alone; (ii) basic colour categorization performs better than random systems of categories; (iii) a category system that performs better than the basic colours could not be found; and (iv) it is not just the general layout of the basic colours that is important, but also the detail. We conclude that (i) the results support the plausibility of an explanation for the basic colours as a result of a pressure-to-optimality and (ii) the basic colours are good categories for machine vision image-retrieval systems. PMID:16849219

  6. Colour harmony of two colour combinations in clothes matching

    NASA Astrophysics Data System (ADS)

    Wicaksono, Sungging Haryo; Fu, Tzu-Hao; Chen, Liang-Ya; Hou, Chien-Yu; Ou, Li-Chen

    2015-01-01

    There are many definitions and theories about colour harmony. But no consistent rules and definitions can be determined. Some previous researches show that there are many factors that influence the colour harmony. Colour harmony is highly depends on the external factors, including the context of colour besides their colour combinations. In the current research an experiment conducted by observing two colour combinations which applied in shirt and trousers. Twenty observers involved in the experiment, consist of ten male and ten female. Each observer predict colour harmony score in 58 samples of shirt and trouser pairs, the colour combination then applied upside down. Based on the experimental results, male and female group has similar tendency in colour harmony score prediction in the same colour samples (correlation coefficient, r=0.84). Upside down colour combinations will change the impression of observer about colour harmony and yields a different value of colour harmony prediction score which indicated from correlation coefficient results of 0.53.

  7. (Computer) Vision without Sight

    PubMed Central

    Manduchi, Roberto; Coughlan, James

    2012-01-01

    Computer vision holds great promise for helping persons with blindness or visual impairments (VI) to interpret and explore the visual world. To this end, it is worthwhile to assess the situation critically by understanding the actual needs of the VI population and which of these needs might be addressed by computer vision. This article reviews the types of assistive technology application areas that have already been developed for VI, and the possible roles that computer vision can play in facilitating these applications. We discuss how appropriate user interfaces are designed to translate the output of computer vision algorithms into information that the user can quickly and safely act upon, and how system-level characteristics affect the overall usability of an assistive technology. Finally, we conclude by highlighting a few novel and intriguing areas of application of computer vision to assistive technology. PMID:22815563

  8. Vision and Driving

    PubMed Central

    Owsley, Cynthia; McGwin, Gerald

    2010-01-01

    Driving is the primary means of personal travel in many countries and is relies heavily on vision for its successful execution. Research over the past few decades has addressed the role of vision in driver safety (motor vehicle collision involvement) and in driver performance (both on-road and using interactive simulators in the laboratory). Here we critically review what is currently known about the role of various aspects of visual function in driving. We also discuss translational research issues on vision screening for licensure and re-licensure and rehabilitation of visually impaired persons who want to drive. PMID:20580907

  9. Colour contribution to children's wayfinding in school environments

    NASA Astrophysics Data System (ADS)

    Helvacıoǧlu, Elif; Olguntürk, Nilgün

    2011-03-01

    The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled 100 primary school children aged seven and eight years old. The study was conducted in four phases. In the first phase, the participants were tested for familiarity with the experiment site and also for colour vision deficiencies by using Ishihara's tests for colour-blindness. In the second phase, they were escorted on the experiment route by the tester one by one, from one starting point to one end point and were asked to lead the tester to the end point by the same route. In the third phase, they were asked to describe verbally the route. In the final phase, they were asked to remember the specific colours at their correct locations. It was found that colour has a significant effect on children's wayfinding performances in school environments. However, there were no differences between different colours in terms of their remembrances in route finding tasks. In addition, the correct identifications of specific colours and landmarks were dependent on their specific locations. Contrary to the literature, gender differences were not found to be significant in the accuracy of route learning performances.

  10. Low Vision

    MedlinePLUS

    ... on. Low Vision What is Low Vision? Everyday Tasks Are Challenging Low vision means that even with ... contact lenses, medicine, or surgery, people find everyday tasks difficult to do. Reading the mail, shopping, cooking, ...

  11. Taking Care of Your Vision

    MedlinePLUS

    ... important parts of keeping your peepers perfect. Vision Basics One of the best things you can do ... For Kids For Parents MORE ON THIS TOPIC Visual Impairment Hand Washing Eyes Pinkeye (Conjunctivitis) Why Should ...

  12. Clinical Trials in Vision Research

    MedlinePLUS

    ... sponsor of vision research in the United States. Basics of Clinical Trials What is a clinical trial? ... treatments and plays a key role in reducing visual impairment and blindness. NEI on Twitter NEI on ...

  13. Evidence for a role of action in colour perception.

    PubMed

    Bompas, Aline; O'Regan, J Kevin

    2006-01-01

    Action is not usually considered to play a role in colour perception. However, sensorimotor theories of perception (eg O'Regan and Noë, 2001 Behavior and Brain Science 24 939-1011) suggest that, on the contrary, the transformations created by action in the sensory input are a necessary condition for all perception. In the case of colour vision, eye movements may explain how a retina with significant irregularities in resolution and cone arrangement (Roorda and Williams, 1999 Nature 397 520-522) could permit the perception of a richly coloured world (Clark and O'Regan, 2000 15th International Conference on Pattern Recognition volume 2: Pattern Recognition and Neural Networks pp 503-506; Skaff et al, 2002 16th International Conference on Pattern Recognition volume 2, pp 681-684). We provide evidence that perception of colour is modified when an artificial coupling is introduced linking eye movements and colour changes. After 40 min of wearing left-field-blue/right-field-yellow spectacles, observers' colour vision adapts so that, after removing the spectacles, white patches seem to become bluer when the eyes move rightwards and yellower when the eyes move leftwards. This induced dependence of colour perception on the direction of eye saccade is shown to be related to the amount of eye movements during exposure. This result, which cannot be explained either by retinal adaptation, or by a conditioned association between colour and side, constitutes first clear evidence for a role of eye movements in perceived colour and argues for the involvement in colour perception of neural mechanisms continuously tuned to sensorimotor contingencies. PMID:16491709

  14. Colour-generating interactions across the corpus callosum.

    PubMed

    Land, E H; Hubel, D H; Livingstone, M S; Perry, S H; Burns, M M

    Human vision has the remarkable property that, over a wide range, changes in the wavelength composition of the source light illuminating a scene result in very little change in the colour of any of the objects. This colour constancy can be explained by the retinex theory, which predicts the colour of a point on any object from a computed relationship between the radiation from that point and the radiation from all the other points in the field of view (Fig. 1). Thus the computations for colour perception occur across large distances in the visual field. It has not been clear, however, whether these long-range interactions take place in the retina or the cortex. Reports that long-range colour interactions can be reproduced binocularly when one band of wavelengths enters one eye and a different band enters the other might seem to establish the cortex as the site of the computation. Many observers, however, see very unsatisfactory colour or no colour at all in this binocular situation, suggesting that the cortex may not be the only site at which the computation is carried out, or even the most important site. We have now tested the role of the cortex in a human subject in whom the nerve fibres connecting cortical areas subserving two separate parts of the visual field had been severed, and find that the cortex is necessary for long-range colour computations. PMID:6855906

  15. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica.

    PubMed

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  16. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica

    PubMed Central

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  17. The Development of Low Vision Therapist Certification.

    ERIC Educational Resources Information Center

    Watson, Gale R.; Quillman, R. Dee; Flax, Marshall; Gerritsen, Bryan

    1999-01-01

    Discusses the development and implementation of the low-vision-therapist certification through the Association for Education and Rehabilitation of the Blind and Visually Impaired. Credentials for professionals in low vision are described, along with required written examination, and the role of the low-vision therapist. (CR)

  18. Tetrachromatic colour space

    NASA Astrophysics Data System (ADS)

    Restrepo, Alfredo

    2012-03-01

    We derive colour spaces of the hue-colourfulness-luminance type, on the basis of a four-dimensional hypercube I4 (I = [0, 1]). The hypercube corresponds to a tetrachromatic colour system, analogous to the three-dimensional RGB cube. In the first derived space the colourfulness is chromatic saturation while in the second one, colourfulness refers to the vividness of the colour, even if it is achromatic. The hue is defined on the basis of an icositetrahedron of 24 triangles that is embedded in the boundary of the hypercube. The boundary of the hypercube is the polytope {4 3 3} (in Sclafli notation) that is a topological 3-sphere. Out of the 24 square faces in the boundary of the hypercube, 6 meet the black vertex and 6 meet the white vertex; the remaining 12 faces form a dodecahedron which is a topological 2-sphere. This equatorial or chromatic dodecahedron is used to define a hue for each point in the hypercube that is not on the achromatic segment; the icositetrahedron results from a division of each of the square faces of the dodecahedron into two triangles. In addition, a hexdecahedron of 16 square faces with the topology of a torus that is also embedded in the boundary of the hypercube, is used to define an alternate two-dimensional hue space.

  19. Colour Mixing Based on Daylight

    ERIC Educational Resources Information Center

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large

  20. Colour processing in complex environments: insights from the visual system of bees.

    PubMed

    Dyer, Adrian G; Paulk, Angelique C; Reser, David H

    2011-03-22

    Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours. PMID:21147796

  1. Colour processing in complex environments: insights from the visual system of bees

    PubMed Central

    Dyer, Adrian G.; Paulk, Angelique C.; Reser, David H.

    2011-01-01

    Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours. PMID:21147796

  2. Vision problems

    MedlinePLUS

    ... which nothing can be seen) Vision loss and blindness are the most severe vision problems. ... that look faded. The most common cause of blindness in people over age 60. Eye infection, inflammation, ...

  3. Can Impaired Vision be Easily, Quickly and Safely Restored toward Health and Maintained Wellness, Using McLeod's Patent Pending Naturoptics Methods?

    NASA Astrophysics Data System (ADS)

    Courtmanche, Amanda; McLeod, Roger; McLeod, David

    2006-10-01

    A healthy eye has its large set of diffraction patterns, generated by the viewed scene, spread across the visible spectrum. Only the two of these simultaneously coincident with foveal cones, and rods, or with extra-foveal cones, are visually useful. This fact and pupil diameter changes with illumination, which cause proportional wavelength changes, drives the healthy visual state. A quasi-monochromatic interval is coincident with foveal cones, and rods. A shorter, partially overlapping interval aligns with extrafoveal cones, with about twenty nanometers separation. Wavelengths follow the Airy disk radius formula. An unhealthy eye is an eyeball deformed by self- induced vision abuse. Incorrect and effectively static stresses in the large external eye muscles displace and distort the patterns. Rebalancing the proper vision and muscle state are safely, quickly and rapidly restored by mimicking natural eye and head movements with naturoptics.

  4. A novel illumination-invariant colour constancy algorithm

    NASA Astrophysics Data System (ADS)

    Torres-Mndez, L. A.; Quiones Muoz, M. L.; Olaya-Bentez, E. J.

    2011-08-01

    The human brain is able to extract the colour of objects no matter the existing illumination conditions which may affect the appearance of their colour. For a person, an object that is red, it will be red regardless of the type of illumination source. However, for a computer algorithm to achieve the same task is not as simple. For vision and robotics applications were feature extraction is essential having such an algorithm is crucial. It is well known from the literature that the colour of an object does not only depend on the chemical composition and shape of its surface but also on the illumination conditions, the intensity, number, location and colour of the sources of illumination as well as the intrinsic and extrinsic characteristics of the sensor used. Based on that knowledge, we propose a simple colour constancy algorithm that uses the quaternion representation of each pixel in the image instead of the commonly used RGB model. We assume linearity in the reception of the luminance spectrum of the charge-coupled device of the camera before variations in the illumination. We have tested our colour constancy algorithm in a variety of images containing different colour objects under different illumination conditions. Our experimental results show the feasibility of the proposed method.

  5. Colour in flux: describing and printing colour in art

    NASA Astrophysics Data System (ADS)

    Parraman, Carinna

    2008-01-01

    This presentation will describe artists, practitioners and scientists, who were interested in developing a deeper psychological, emotional and practical understanding of the human visual system who were working with wavelength, paint and other materials. From a selection of prints at The Prints and Drawings Department at Tate London, the presentation will refer to artists who were motivated by issues relating to how colour pigment was mixed and printed, to interrogate and explain colour perception and colour science, and in art, how artists have used colour to challenge the viewer and how a viewer might describe their experience of colour. The title Colour in Flux refers, not only to the perceptual effect of the juxtaposition of one colour pigment with another, but also to the changes and challenges for the print industry. In the light of screenprinted examples from the 60s and 70s, the presentation will discuss 21 st century ideas on colour and how these notions have informed the Centre for Fine Print Research's (CFPR) practical research in colour printing. The latter part of this presentation will discuss the implications for the need to change methods in mixing inks that moves away from existing colour spaces, from non intuitive colour mixing to bespoke ink sets, colour mixing approaches and colour mixing methods that are not reliant on RGB or CMYK.

  6. Flower Colour: How Bumblebees Handle Colours with Perceptually Changing Hues.

    PubMed

    Lunau, Klaus

    2016-03-21

    Colours are floral signals enabling bees to detect, inspect and discriminate flowers in a multitasking world. Behavioural tests now show that trained bumblebees find iridescent coloured targets more quickly and that weak iridescence does not corrupt target identification. PMID:27003883

  7. Colour image segmentation using unsupervised clustering technique for acute leukemia images

    NASA Astrophysics Data System (ADS)

    Halim, N. H. Abd; Mashor, M. Y.; Nasir, A. S. Abdul; Mustafa, N.; Hassan, R.

    2015-05-01

    Colour image segmentation has becoming more popular for computer vision due to its important process in most medical analysis tasks. This paper proposes comparison between different colour components of RGB(red, green, blue) and HSI (hue, saturation, intensity) colour models that will be used in order to segment the acute leukemia images. First, partial contrast stretching is applied on leukemia images to increase the visual aspect of the blast cells. Then, an unsupervised moving k-means clustering algorithm is applied on the various colour components of RGB and HSI colour models for the purpose of segmentation of blast cells from the red blood cells and background regions in leukemia image. Different colour components of RGB and HSI colour models have been analyzed in order to identify the colour component that can give the good segmentation performance. The segmented images are then processed using median filter and region growing technique to reduce noise and smooth the images. The results show that segmentation using saturation component of HSI colour model has proven to be the best in segmenting nucleus of the blast cells in acute leukemia image as compared to the other colour components of RGB and HSI colour models.

  8. Vision Changes in Space - Duration: 2 minutes, 20 seconds.

    NASA Video Gallery

    This Human Research Program 'Research to Outreach' video featuring NASA Clinical Translational Scientist Jennifer Fogarty explains the risk of vision impairment both during and after spaceflight, i...

  9. Mimicry, colour forms and spectral sensitivity of the bluestriped fangblenny, Plagiotremus rhinorhynchos

    PubMed Central

    Cheney, Karen L.; Skogh, Charlotta; Hart, Nathan S.; Marshall, N. Justin

    2009-01-01

    Animals change their body coloration for a variety of purposes including communication, thermoregulation and crypsis. The cues that trigger adaptive colour change are often unclear, and the role of colour vision remains largely untested. Here, we investigated the bluestriped fangblenny (Plagiotremus rhinorhynchos), an aggressive mimic that changes its body coloration to impersonate a variety of coral reef fishes. In this field, we determined the fish species that the fangblenny associated with and measured the spectral reflectance of mimics and their models. We measured the spectral absorbance characteristics of the retinal photoreceptor visual pigments in the bluestriped fangblenny using microspectrophotometry and found it to have rod photoreceptors (?max 498?nm), single cones (449?nm) and double cones (561?nm principal member; 520?nm accessory member). Using theoretical vision models, fangblennies could discriminate between the colours they adopted and the colours of the fish they associated with. Potential signal receivers (Abudefduf abdominalis and Ctenochaetus strigosus) perceived colours of most mimics to closely resemble fishes they associated with. However, fishes with ultraviolet-sensitive visual pigments were better at discriminating between mimics and models. Therefore, colour vision could be used by fangblennies when initiating colour change enabling them to accurately resemble fishes they associate with and to avoid detection by signal receivers. PMID:19324827

  10. Colouration in crab spiders: substrate choice and prey attraction.

    PubMed

    Heiling, Astrid M; Chittka, Lars; Cheng, Ken; Herberstein, Marie E

    2005-05-01

    Australian crab spiders Thomisus spectabilis ambush pollinating insects, such as honeybees (Apis mellifera) on flowers, and can change their body colour between yellow and white. It is traditionally assumed that the spiders change their colour to match the flower colour, thus rendering them cryptic to insect prey. Here, we test this assumption combining state-of-the-art knowledge of bee vision and behavioural experiments. In the field, yellow spiders are only found on yellow daisies (Chrysanthemum frutescens), whereas white spiders are found on yellow and white daisies. These field patterns were confirmed in the laboratory. When given the choice between white and yellow daisies, yellow spiders preferred yellow daisies, whereas white spiders showed only a slight but non-significant preference for white flowers. Thus, T. spectabilis select background colours according to their own body colour. When viewed from a distance, bees use an achromatic signal produced by their green receptors for target detection. Through this visual channel, white spiders on white flowers, and yellow spiders on yellow flowers are virtually undetectable. From a closer distance of a few centimetres, when bees evaluate colour contrast, the combination of spider colour against different flower backgrounds affected the response of honeybees, but not in ways predicted by a classical crypsis/conspicuousness interpretation. Yellow spiders on yellow flowers are not perfectly matched when interpreted through the colour vision of a honeybee. Nevertheless, honeybees showed indifference to the presence of a spider, equally landing on vacant or spider-occupied flowers. Likewise, white spiders are poorly hidden on white flowers, as white spiders reflect ultraviolet light strongly, while white flowers do not. Surprisingly, bees are attracted to this contrast, and significantly more honeybees preferred white flowers occupied by white spiders. White spiders on yellow flowers produce the highest colour contrast and bees again preferred spider-occupied flowers. Yellow spiders on white flowers were the only pairing where bees rejected spider-occupied flowers, especially in cases where the contrast between the two was relatively strong. Thus, T. spectabilis select flower colours adaptively in a way that deceives honeybees, or at least does not deter them. PMID:15879060

  11. Low Vision

    MedlinePLUS

    ... by Age, Gender, and Race/Ethnicity 2010 U.S. Age-Specific Prevalence Rates for Low Vision by Age, and Race/Ethnicity Table for 2010 U.S. Age- ... Prevalent Cases of Low Vision (in thousands) by Age, and Race/Ethnicity Table for 2010 U.S. Prevalent ...

  12. Quantifying Variability of Avian Colours: Are Signalling Traits More Variable?

    PubMed Central

    Delhey, Kaspar; Peters, Anne

    2008-01-01

    Background Increased variability in sexually selected ornaments, a key assumption of evolutionary theory, is thought to be maintained through condition-dependence. Condition-dependent handicap models of sexual selection predict that (a) sexually selected traits show amplified variability compared to equivalent non-sexually selected traits, and since males are usually the sexually selected sex, that (b) males are more variable than females, and (c) sexually dimorphic traits more variable than monomorphic ones. So far these predictions have only been tested for metric traits. Surprisingly, they have not been examined for bright coloration, one of the most prominent sexual traits. This omission stems from computational difficulties: different types of colours are quantified on different scales precluding the use of coefficients of variation. Methodology/Principal Findings Based on physiological models of avian colour vision we develop an index to quantify the degree of discriminable colour variation as it can be perceived by conspecifics. A comparison of variability in ornamental and non-ornamental colours in six bird species confirmed (a) that those coloured patches that are sexually selected or act as indicators of quality show increased chromatic variability. However, we found no support for (b) that males generally show higher levels of variability than females, or (c) that sexual dichromatism per se is associated with increased variability. Conclusions/Significance We show that it is currently possible to realistically estimate variability of animal colours as perceived by them, something difficult to achieve with other traits. Increased variability of known sexually-selected/quality-indicating colours in the studied species, provides support to the predictions borne from sexual selection theory but the lack of increased overall variability in males or dimorphic colours in general indicates that sexual differences might not always be shaped by similar selective forces. PMID:18301766

  13. Colour based fire detection method with temporal intensity variation filtration

    NASA Astrophysics Data System (ADS)

    Trambitckii, K.; Anding, K.; Musalimov, V.; Linß, G.

    2015-02-01

    Development of video, computing technologies and computer vision gives a possibility of automatic fire detection on video information. Under that project different algorithms was implemented to find more efficient way of fire detection. In that article colour based fire detection algorithm is described. But it is not enough to use only colour information to detect fire properly. The main reason of this is that in the shooting conditions may be a lot of things having colour similar to fire. A temporary intensity variation of pixels is used to separate them from the fire. These variations are averaged over the series of several frames. This algorithm shows robust work and was realised as a computer program by using of the OpenCV library.

  14. Double Vision.

    PubMed

    Lee, Michael S.; Volpe, Nicholas J.

    2001-07-01

    When evaluating a patient with a complaint of double vision, it is important to distinguish monocular versus binocular diplopia, which are differentiated by asking the patient to cover each eye separately. In the setting of binocular double vision, one of the two images disappears when either eye is covered, because diplopia is the result of ocular misalignment. On the other hand, monocular double vision resolves when the affected eye is covered, but remains when the opposite eye is occluded. Causes of monocular diplopia include cataract, refractive error, and retinal disease, which can be managed accordingly by an ophthalmologist. However, an unusual form of monocular double vision can occur in the setting of cortical dysfunction. Cerebral polyopia describes the perception of multiple images and arises from an occipital disturbance. It can occur with migraine headaches and can be accompanied by a homonymous hemianopia. Palinopsia refers to the persistence of an image that is no longer in view (visual perseveration or stroboscopic effect) and results from an occipital lesion as well. The exact mechanism of polyopia and palinopsia are uncertain and both conditions are extremely rare. The majority of this discussion will focus on binocular double vision and its management. The main treatment objective of binocular diplopia is to restore the largest area of single binocular vision. Ideally, patients would be able to achieve single vision in all fields of gaze, but this is not always possible. The majority of patients are treated with either prism lenses or eye muscle surgery. PMID:11389808

  15. Prevalence and Causes of Blindness and Visual Impairment in Sokoto State, Nigeria: Baseline Data for Vision 2020: The Right to Sight Eye Care Programme

    PubMed Central

    Muhammad, Nasiru; Mansur, Rabiu M.; Dantani, Adamu M.; Elhassan, Elizabeth; Isiyaku, Sunday

    2011-01-01

    Purpose: To estimate the prevalence of low vision and blindness, identify the causes, and suggest policies for an effective eye care program based on 2005 data from Sokoto State, Nigeria. Materials and Methods: A stratified two-stage cluster sampling method was used to quantify the prevalence of blindness and the causes from 4 health zones in Sokoto State. Subjects were evaluated using a magnifying loupe, direct ophthalmoscope and torchlight. Data were collected based on the World Health Organization prevention of blindness coding for an eye examination. Prevalences with 95% confidence intervals (CI) were calculated and surgical coverage for causes of blindness was also analyzed. Results: The response rate was 91%. The prevalence of bilateral blindness was 1.9% (95% CI: 1.52.3%) ranging from 1.6% to 2.0% across the four health zones. The prevalence was 2.1% (95% CI: 1.62.6%) in males and 1.6% (95% CI: 1.12.1%) in females. The leading cause of bilateral blindness was cataract (51.6%), followed by uncorrected aphakia (20.9%) and glaucoma (11%). The prevalence of bilateral operable cataract was 1.9% (95% CI: 1.52.3%). The cataract surgical coverage (individuals with visual acuity <6/60) for the study was lower than the couching coverage (4.4% vs. 14.9%, respectively). Surgical coverage for trichiasis was 4.4%. The major barrier to cataract and glaucoma management was cost. Conclusions: The prevalence of blindness in Sokoto State is high yet the main causes are largely avoidable. Barriers can be reduced by appropriate health education regarding the eye care program and the provision of integrated, sustainable, affordable and equitable services. PMID:21731322

  16. Computer vision

    NASA Technical Reports Server (NTRS)

    Gennery, D.; Cunningham, R.; Saund, E.; High, J.; Ruoff, C.

    1981-01-01

    The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed.

  17. Computational vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1981-01-01

    The range of fundamental computational principles underlying human vision that equally apply to artificial and natural systems is surveyed. There emerges from research a view of the structuring of vision systems as a sequence of levels of representation, with the initial levels being primarily iconic (edges, regions, gradients) and the highest symbolic (surfaces, objects, scenes). Intermediate levels are constrained by information made available by preceding levels and information required by subsequent levels. In particular, it appears that physical and three-dimensional surface characteristics provide a critical transition from iconic to symbolic representations. A plausible vision system design incorporating these principles is outlined, and its key computational processes are elaborated.

  18. Neurological Vision Rehabilitation: Description and Case Study

    ERIC Educational Resources Information Center

    Kingston, John; Katsaros, Jennifer; Vu, Yurika; Goodrich, Gregory L.

    2010-01-01

    The wars in Afghanistan and Iraq have been notable for the high rates of traumatic brain injury (TBI) that have been incurred by the troops. Visual impairments often occur following TBI and present new challenges for rehabilitation. We describe a neurological vision rehabilitation therapy that addresses the unique needs of patients with vision

  19. A Low Vision Reading Comprehension Test.

    ERIC Educational Resources Information Center

    Watson, G. R.; And Others

    1996-01-01

    Fifty adults (ages 28-86) with macular degeneration were given the Low Vision Reading Comprehension Assessment (LVRCA) to test its reliability and validity in evaluating the reading comprehension of those with vision impairments. The LVRCA was found to take only nine minutes to administer and was a valid and reliable tool. (CR)

  20. Color Vision Deficits and Literacy Acquisition.

    ERIC Educational Resources Information Center

    Hurley, Sandra Rollins

    1994-01-01

    Shows that color blindness, whether partial or total, inhibits literacy acquisition. Offers a case study of a third grader with impaired color vision. Presents a review of literature on the topic. Notes that people with color vision deficits are often unaware of the handicap. (RS)

  1. Efficacy of a Low Vision Patient Consultation

    ERIC Educational Resources Information Center

    Siemsen, Dennis W.; Bergstrom, A. Ren?e; Hathaway, Julie C.

    2005-01-01

    A variety of obstacles can prevent persons or individuals with low vision from deriving the greatest possible benefit from the rehabilitation process, including inadequate understanding of their visual impairment, lack of knowledge about available services, and misconceptions about low vision devices. This study explores the use of a…

  2. Vision Underwater.

    ERIC Educational Resources Information Center

    Levine, Joseph S.

    1980-01-01

    Provides information regarding underwater vision. Includes a discussion of optically important interfaces, increased eye size of organisms at greater depths, visual peculiarities regarding the habitat of the coastal environment, and various pigment visual systems. (CS)

  3. Improving Vision

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Many people are familiar with the popular science fiction series Star Trek: The Next Generation, a show featuring a blind character named Geordi La Forge, whose visor-like glasses enable him to see. What many people do not know is that a product very similar to Geordi's glasses is available to assist people with vision conditions, and a NASA engineer's expertise contributed to its development. The JORDY(trademark) (Joint Optical Reflective Display) device, designed and manufactured by a privately-held medical device company known as Enhanced Vision, enables people with low vision to read, write, and watch television. Low vision, which includes macular degeneration, diabetic retinopathy, and glaucoma, describes eyesight that is 20/70 or worse, and cannot be fully corrected with conventional glasses.

  4. Colour management: a workable solution.

    PubMed

    Lattka, Kirsteen

    2004-03-01

    Within clinical photography, colour reproduction has always been a contentious issue. With the development of new technologies, the variables affecting colour reproduction have changed and photographers have altered practices, moving away from the realm of film to digital photographic imaging systems. In order to standardize the output of digital clinical images, the author researched, and successfully implemented, the GretagMacbeth EYE-ONE Pro colour management system. This system, which is maintained on a monthly basis, has ensured a colour-consistent, reliable and efficient workflow throughout the digital clinical set-up. PMID:15203696

  5. Assessing Functional Vision Using Microcomputers.

    ERIC Educational Resources Information Center

    Spencer, Simon; Ross, Malcolm

    1989-01-01

    The paper describes a software system which uses microcomputers to aid in the assessment of functional vision in visually impaired students. The software also aims to be visually stimulating and to develop hand-eye coordination, visual memory, and cognitive abilities. (DB)

  6. A colourful clock.

    PubMed

    van Diepen, Hester C; Foster, Russell G; Meijer, Johanna H

    2015-05-01

    Circadian rhythms are an essential property of life on Earth. In mammals, these rhythms are coordinated by a small set of neurons, located in the suprachiasmatic nuclei (SCN). The environmental light/dark cycle synchronizes (entrains) the SCN via a distinct pathway, originating in a subset of photosensitive retinal ganglion cells (pRGCs) that utilize the photopigment melanopsin (OPN4). The pRGCs are also innervated by rods and cones and, so, are both endogenously and exogenously light sensitive. Accumulating evidence has shown that the circadian system is sensitive to ultraviolet (UV), blue, and green wavelengths of light. However, it was unclear whether colour perception itself can help entrain the SCN. By utilizing both behavioural and electrophysiological recording techniques, Walmsley and colleagues show that multiple photic channels interact and enhance the capacity of the SCN to synchronize to the environmental cycle. Thus, entrainment of the circadian system combines both environmental irradiance and colour information to ensure that internal and external time are appropriately aligned. PMID:25996907

  7. Across light: through colour

    NASA Astrophysics Data System (ADS)

    Azevedo, Isabel; Richardson, Martin; Bernardo, Luis Miguel

    2012-03-01

    The speed at which our world is changing is reflected in the shifting way artistic images are created and produced. Holography can be used as a medium to express the perception of space with light and colour and to make the material and the immaterial experiments with optical and digital holography. This paper intends to be a reflection on the final product of that process surrounding a debate of ideas for new experimental methodologies applied to holographic images. Holography is a time-based medium and the irretrievable linear flow of time is responsible for a drama, unique to traditional cinematography. If the viewers move to left or right, they see glimpses of the next scene or the previous one perceived a second ago. This interaction of synthetic space arises questions such as: can we see, in "reality", two forms in the same space? Trying to answer this question, a series of works has been created. These concepts are embryonic to a series of digital art holograms and lenticulars technique's titled "Across Light: Through Colour". They required some technical research and comparison between effects from different camera types, using Canon IS3 and Sony HDR CX105.

  8. Why do mice have ultra-violet vision?

    PubMed

    Gouras, Peter; Ekesten, Bjorn

    2004-12-01

    Murine vision has become a fascinating entity due to discoveries about the histology and physiology of its retina over the past decade. It has two varieties of cones, one serving the traditional green-yellow region of the vision spectrum and another serving the ultra-violet region, essentially invisible to man and many other mammal. This puts unusual constraints on the optical transmission of the murine eye, in particular its relatively large lens. Its ultra-violet vision appears to involve its upper much more than its lower visual field, providing a heuristic clue to its purpose. In addition behavioural evidence exists for colour vision in mice. On the other hand there is unequivocal evidence that many murine cones contain both cone photopigments, an unrealistic but not impossible arrangement for colour vision. A better understanding of how ultra-violet vision is interwoven into cone and rod vision and possible colour vision can be clarified by analysing the responses of single retinal neurons. This paper reviews the current information on this topic and provides new insights from single retinal ganglion cell recordings. PMID:15642326

  9. Digital colour management system for colour parameters reconstruction

    NASA Astrophysics Data System (ADS)

    Grudzinski, Karol; Lasmanowicz, Piotr; Assis, Lucas M. N.; Pawlicka, Agnieszka; Januszko, Adam

    2013-10-01

    Digital Colour Management System (DCMS) and its application to new adaptive camouflage system are presented in this paper. The DCMS is a digital colour rendering method which would allow for transformation of a real image into a set of colour pixels displayed on a computer monitor. Consequently, it can analyse pixels' colour which comprise images of the environment such as desert, semi-desert, jungle, farmland or rocky mountain in order to prepare an adaptive camouflage pattern most suited for the terrain. This system is described in present work as well as the use the subtractive colours mixing method to construct the real time colour changing electrochromic window/pixel (ECD) for camouflage purpose. The ECD with glass/ITO/Prussian Blue(PB)/electrolyte/CeO2-TiO2/ITO/glass configuration was assembled and characterized. The ECD switched between green and yellow after +/-1.5 V application and the colours have been controlled by Digital Colour Management System and described by CIE LAB parameters.

  10. Distinctive convergence in Australian floral colours seen through the eyes of Australian birds

    PubMed Central

    Burd, Martin; Stayton, C. Tristan; Shrestha, Mani; Dyer, Adrian G.

    2014-01-01

    We used a colour-space model of avian vision to assess whether a distinctive bird pollination syndrome exists for floral colour among Australian angiosperms. We also used a novel phylogenetically based method to assess whether such a syndrome represents a significant degree of convergent evolution. About half of the 80 species in our sample that attract nectarivorous birds had floral colours in a small, isolated region of colour space characterized by an emphasis on long-wavelength reflection. The distinctiveness of this red arm region was much greater when colours were modelled for violet-sensitive (VS) avian vision than for the ultraviolet-sensitive visual system. Honeyeaters (Meliphagidae) are the dominant avian nectarivores in Australia and have VS vision. Ancestral state reconstructions suggest that 31 lineages evolved into the red arm region, whereas simulations indicate that an average of five or six lineages and a maximum of 22 are likely to have entered in the absence of selection. Thus, significant evolutionary convergence on a distinctive floral colour syndrome for bird pollination has occurred in Australia, although only a subset of bird-pollinated taxa belongs to this syndrome. The visual system of honeyeaters has been the apparent driver of this convergence. PMID:24573847

  11. Distinctive convergence in Australian floral colours seen through the eyes of Australian birds.

    PubMed

    Burd, Martin; Stayton, C Tristan; Shrestha, Mani; Dyer, Adrian G

    2014-04-22

    We used a colour-space model of avian vision to assess whether a distinctive bird pollination syndrome exists for floral colour among Australian angiosperms. We also used a novel phylogenetically based method to assess whether such a syndrome represents a significant degree of convergent evolution. About half of the 80 species in our sample that attract nectarivorous birds had floral colours in a small, isolated region of colour space characterized by an emphasis on long-wavelength reflection. The distinctiveness of this 'red arm' region was much greater when colours were modelled for violet-sensitive (VS) avian vision than for the ultraviolet-sensitive visual system. Honeyeaters (Meliphagidae) are the dominant avian nectarivores in Australia and have VS vision. Ancestral state reconstructions suggest that 31 lineages evolved into the red arm region, whereas simulations indicate that an average of five or six lineages and a maximum of 22 are likely to have entered in the absence of selection. Thus, significant evolutionary convergence on a distinctive floral colour syndrome for bird pollination has occurred in Australia, although only a subset of bird-pollinated taxa belongs to this syndrome. The visual system of honeyeaters has been the apparent driver of this convergence. PMID:24573847

  12. Colour invariant target recognition in multiple camera CCTV surveillance

    NASA Astrophysics Data System (ADS)

    Soori, Umair; Yuen, P. W. T.; Ibrahim, I.; Han, J.; Tsitiridis, A.; Hong, K.; Chen, T.; Jackman, J.; James, D.; Richardson, M.

    2011-11-01

    People tracking in crowded scene have been a popular, and at the same time a very difficult topic in computer vision. It is mainly because of the difficulty for the acquisition of intrinsic signatures of targets from a single view of the scene. Many factors, such as variable illumination conditions and viewing angles, will induce illusive modification of intrinsic signatures of targets. The objective of this paper is to verify if colour constancy (CC) approach really helps people tracking in CCTV network system. We have testified a number of CC algorithms together with various colour descriptors, to assess the efficiencies of people recognitions from multi-camera i-LIDS data set via receiver operation characteristics (ROC). It is found that when CC is applied together with some form of colour restoration mechanisms such as colour transfer, it does improve people recognition by at least a factor of 2. An elementary luminance based CC coupled with a pixel based colour transfer algorithm have been developed and it is reported in this paper.

  13. Texture Variations Suppress Suprathreshold Brightness and Colour Variations

    PubMed Central

    Schofield, Andrew J.; Kingdom, Frederick A. A.

    2014-01-01

    Discriminating material changes from illumination changes is a key function of early vision. Luminance cues are ambiguous in this regard, but can be disambiguated by co-incident changes in colour and texture. Thus, colour and texture are likely to be given greater prominence than luminance for object segmentation, and better segmentation should in turn produce stronger grouping. We sought to measure the relative strengths of combined luminance, colour and texture contrast using a suprathreshhold, psychophysical grouping task. Stimuli comprised diagonal grids of circular patches bordered by a thin black line and contained combinations of luminance decrements with either violet, red, or texture increments. There were two tasks. In the Separate task the different cues were presented separately in a two-interval design, and participants indicated which interval contained the stronger orientation structure. In the Combined task the cues were combined to produce competing orientation structure in a single image. Participants had to indicate which orientation, and therefore which cue was dominant. Thus we established the relative grouping strength of each cue pair presented separately, and compared this to their relative grouping strength when combined. In this way we observed suprathreshold interactions between cues and were able to assess cue dominance at ecologically relevant signal levels. Participants required significantly more luminance and colour compared to texture contrast in the Combined compared to Separate conditions (contrast ratios differed by about 0.1 log units), showing that suprathreshold texture dominates colour and luminance when the different cues are presented in combination. PMID:25502555

  14. Grey leaves in an alpine plant: a cryptic colouration to avoid attack?

    PubMed

    Niu, Yang; Chen, Gao; Peng, De-Li; Song, Bo; Yang, Yang; Li, Zhi-Min; Sun, Hang

    2014-08-01

    Cryptic colouration is a common predation-avoidance strategy in animals that is postulated to occur in plants, but few experimental studies have rigorously tested this hypothesis. We investigated the colouration of Corydalis benecincta, an alpine plant with remarkably dimorphic leaf colours (grey and green), based on a cost-benefit analysis. First we tested the premise that herbivores (Parnassius butterflies) cannot distinguish grey leaves from a scree background by spectrographic measurements and by estimating discriminability between leaves and scree using a butterfly colour vision model. Then we estimated the potential costs of inconspicuousness by comparing the photosynthetic performance and visual attractiveness to flower visitors of the two colour morphs. Finally, we examined the potential benefits of inconspicuousness by comparing damage, survivorship and female reproductive success. It is difficult for herbivores to distinguish grey-coloured morphs against the background. This grey colour originates in a combination of anthocyanins and chlorophylls. The two colour morphs had similar photosynthetic performance, visual attractiveness and female reproductive success. However, grey morphs had significantly lower herbivore damage and higher survivorship. Grey leaves benefit C.benecincta by reducing herbivory with low investment in anthocyanin synthesis, and little cost on photosynthesis and mating opportunity. This cryptic colouration may have evolved through selection pressure imposed by visually foraging herbivores. PMID:24800901

  15. Age-Related Psychophysical Changes and Low Vision

    PubMed Central

    Dagnelie, Gislin

    2013-01-01

    When considering the burden of visual impairment on aging individuals and society at large, it is important to bear in mind that vision changes are a natural aspect of aging. In this article, we consider vision changes that are part of normal aging, the prevalence of abnormal vision changes caused by disorders of the visual system, and the anticipated incidence and impact of visual impairment as the US population ages. We then discuss the services available to reduce the impact of vision loss, and the extent to which those services can and should be improved, not only to be better prepared for the anticipated increase in low vision over the coming decades, but also to increase the awareness of interactions between visual impairment and comorbidities that are common among the elderly. Finally, we consider how to promote improved quality, availability, and acceptance of low vision care to lessen the impact of visual impairment on individuals, and its burden on society. PMID:24335074

  16. Colourful Semantics: A Clinical Investigation

    ERIC Educational Resources Information Center

    Bolderson, Sarah; Dosanjh, Christine; Milligan, Claudine; Pring, Tim; Chiat, Shula

    2011-01-01

    Children with language difficulties often omit verbs and grammatical elements and fail to complete sentences. Bryan (1997) described "colourful semantics", a therapy she used to treat a 5-year-old boy. The therapy uses colour coding to highlight the predicate argument structure of sentences. This study further tested the therapy's effectiveness by

  17. Complementary Colours for a Physicist

    ERIC Educational Resources Information Center

    Babic, Vitomir; Cepic, Mojca

    2009-01-01

    This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing

  18. Visual Impairment, Including Blindness

    MedlinePLUS

    ... and appliances, Braille, closed circuit TVs, guide dog schools, low vision, and technology. http://www.nfb.org/living Education for Students with Blindness or Visual Impairment | Entire section of Perkins School for the Blind’s website. http://www.perkins.org/ ...

  19. Computer vision

    SciTech Connect

    Rosenfeld, A.

    1982-04-01

    Over the past 25 years, much of the work on applications of pattern recognition, and a significant fraction of the work in artificial intelligence, has dealt with the analysis and in artificial intelligence, has dealt with the analysis and interpretation of images. This subject has been variously known as pictorial pattern recognition, image analysis, scene analysis, image understanding, and computer vision. Its applications include document processing (character recognition, etc.), microscopy, radiology, industrial automation (inspection, robot vision), remote sensing, navigation, and reconaissance, to name only the major areas. Many ad hoc techniques for analyzing images have been developed, so that a large assortment of tools is now available for solving practical problems in this field. Most important, during the past few years the field has begun to develop a scientific basis. This paper outlines the major steps in the computer vision process, and summarizes the state of the art with respect to each of these steps.

  20. Color vision.

    PubMed

    Swanson, William H; Cohen, Jay M

    2003-06-01

    Many visual disorders produce acquired color vision defects. Color vision theory emphasizes several stages of visual processing: prereceptoral filters (lens, macular pigment, pupil), cone photopigments (L-, M-, and S-cones), and postreceptoral processes (red-green, S-cone, and luminance channels). Congenital color defects, which affect 8% to 10% of males and 0.4% to 0.5% of females, result from alterations in the photopigment absorption spectra or the absence of one or more photopigments. The most common defects are color vision deficiencies (protan and deutan defects), which are milder than the rarer achromatopsias (complete loss of color vision). Acquired color vision defects can be attributed to a number of different causes: alteration of prereceptoral filters, reduced cone photopigment optical density, greater loss of one cone type than the others, and disruption of postreceptoral processes. Acquired color vision defects have been divided into three classes: type 1, red-green defect with scotopization; type 2, red-green defect without scotopization; and type 3, blue defects (with or without pseudoprotanomaly). Blue defects are usually type 3 acquired defects because congenital tritan defects have an incidence of one in several tens of thousands. Red-green defects can be acquired or congenital, and ruling out acquired defects can require a battery of tests (plates and arrangement tests, anomaloscopy, perhaps genetic analysis). Color vision tests must be administered carefully (with a standard illuminant and protocol), and pupillary miosis or high lens density should be noted and their possible effects considered when interpreting test results. Plate tests provide a simple screening method but do not provide a diagnosis. Arrangement tests and anomaloscope testing take more time and make greater demands on the tester, but they provide a more thorough evaluation. When standard protocols are followed and results are interpreted in terms of prereceptoral filters, photopigment optical density, cone loss, and disruption of postreceptoral processes, a battery of color vision tests can be useful in the differential diagnosis, after progression of the disease, and for evaluating the effectiveness of treatment. PMID:12809157

  1. The Need for a Uniform Method of Recording and Reporting Functional Vision Assessments

    ERIC Educational Resources Information Center

    Shaw, Rona; Russotti, Joanne; Strauss-Schwartz, Judy; Vail, Helen; Kahn, Ronda

    2009-01-01

    The use of functional vision by school-age students who have visual impairments, including those with additional disabilities, is typically reported by teachers of students with visual impairments. Functional vision assessments determine how well a student uses his or her vision to perform tasks throughout the school day. The information that is

  2. The Effect of an On-Site Vision Examination on Adherence to Vision Screening Recommendations

    ERIC Educational Resources Information Center

    Chu, Raymond; Huang, Kristine; Barnhardt, Carmen; Chen, Angela

    2015-01-01

    Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening

  3. The Effect of an On-Site Vision Examination on Adherence to Vision Screening Recommendations

    ERIC Educational Resources Information Center

    Chu, Raymond; Huang, Kristine; Barnhardt, Carmen; Chen, Angela

    2015-01-01

    Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening…

  4. Linguistic relativism and colour cognition.

    PubMed

    Pilling, Michael; Davies, Ian R L

    2004-11-01

    Native speakers of two languages (English and Ndonga) were compared on three colour cognition tasks (sorting, triads and visual search) in a test of the linguistic relativity hypothesis (Whorf, 1956). The colour lexicons of these two languages differ because Ndonga has no basic terms for ORANGE, PINK and PURPLE, and stimuli were chosen to exploit this difference. On the sorting task (sorting into similarity-groups) for each language, nominally similar colours were grouped together more often than nominally dissimilar colours. On the triads task (choosing the most different of three colours), when the most nominally isolated colour differed for the two language-groups, each group tended to choose their nominal isolate. On the search task (scanning for target colours among distractors), targets were either in a different English category than distractors (cross-category), or some distractors were in the same English category as distractors (within-category). The 'cost' in speed of having within-category distractors was much greater for the English than for the Ndonga. Overall, these data suggest that a core universal component is modulated by a small relativist influence. The differences in the visual search task are consistent with language affecting pre-attentive processes (an indirect language effect) as well as exerting on-line influences (a direct effect). PMID:15527531

  5. Colour thresholding in video imaging.

    PubMed Central

    Fermin, C D; Degraw, S

    1995-01-01

    The basic aspects of video imaging are reviewed as they relate to measurements of histological and anatomical features, with particular emphasis on the advantages and disadvantages of colour and black-and-white imaging modes. In black-and-white imaging, calculations are based on the manipulation of picture elements (pixels) that contain 0-255 levels of information. Black is represented by the absence of light (0) and white by 255 grades of light. In colour imaging, the pixels contain variation of hues for the primary (red, green and blue) and secondary (magenta, yellow, cyan, pink) colours. Manipulation of pixels with colour information is more computer intense than that for black-and-white pixels, because there are over 16 million possible combinations of colour in a system with a 24-bit resolution. The narrow 128 possible grades of separation in black and white often makes distinction between pixels with overlapping intensities difficult. Such difficulty is greatly reduced by colour thresholding of systems that base the representation of colour on a combination of hue-saturation-intensity (HSI) format. Images Fig. 3 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 PMID:7559121

  6. Low vision rehabilitation. Finding capable people behind damaged eyeballs.

    PubMed Central

    Fletcher, D. C.; Shindell, S.; Hindman, T.; Schaffrath, M.

    1991-01-01

    Loss of vision is a common physical impairment in America today. Comprehensive low vision rehabilitation programs can have dramatic results in increasing the independence and productivity of affected persons. Rehabilitation efforts must be tailored to the type of vision loss and to specific functional implications. Every effort should be made to enhance the residual vision. Activities of daily living, orientation and mobility, and psychological concerns must be addressed. PMID:1866949

  7. Training Visions

    ERIC Educational Resources Information Center

    Training, 2011

    2011-01-01

    In this article, "Training" asks the 2011 winners to give their predictions for what training--either in general or specifically at their companies--will look like in the next five to 10 years. Perhaps their "training visions" will spark some ideas in one's organization--or at least help prepare for what might be coming in the next decade or so.

  8. Presidential Visions.

    ERIC Educational Resources Information Center

    Gallin, Alice, Ed.

    1992-01-01

    This journal issue is devoted to the theme of university presidents and their visions of the future. It presents the inaugural addresses and speeches of 16 Catholic college and university presidents focusing on their goals, ambitions, and reasons for choosing to become higher education leaders at this particular time in the history of education in

  9. The colours of extant mammals.

    PubMed

    Caro, Tim

    2013-01-01

    In this review I survey pelage and skin colouration patterns of the 29 orders of extant mammals and assess their functional significance. The vast majority of mammals are shades of grey or brown. Concealment is probably the principal evolutionary driver of pelage colouration in this Class likely through background matching and self-shadow concealment. A small minority of species are aposematic while many others have distinctive markings used in intraspecific and interspecific communication although the meaning of these markings is unclear. Colouration in mammals also has physiological consequences but these are barely understood as yet. PMID:23567208

  10. Blindness and vision loss

    MedlinePLUS

    ... the United States. Vision loss refers to the partial or complete loss of vision. This vision loss may happen suddenly or over a period of time. Some types of vision loss never lead to complete blindness.

  11. Low Vision FAQs

    MedlinePLUS

    ... at NEI Education Programs Training and Jobs Healthy Vision Diabetes Diabetes Home How Much Do You Know? ... los Ojos Cómo hablarle a su oculista Low Vision FAQs Listen What is low vision? Low vision ...

  12. Can colours be used to segment words when reading?

    PubMed

    Perea, Manuel; Tejero, Pilar; Winskel, Heather

    2015-07-01

    Rayner, Fischer, and Pollatsek (1998, Vision Research) demonstrated that reading unspaced text in Indo-European languages produces a substantial reading cost in word identification (as deduced from an increased word-frequency effect on target words embedded in the unspaced vs. spaced sentences) and in eye movement guidance (as deduced from landing sites closer to the beginning of the words in unspaced sentences). However, the addition of spaces between words comes with a cost: nearby words may fall outside high-acuity central vision, thus reducing the potential benefits of parafoveal processing. In the present experiment, we introduced a salient visual cue intended to facilitate the process of word segmentation without compromising visual acuity: each alternating word was printed in a different colour (i.e., ). Results only revealed a small reading cost of unspaced alternating colour sentences relative to the spaced sentences. Thus, present data are a demonstration that colour can be useful to segment words for readers of spaced orthographies. PMID:26002618

  13. The Role of Organizations in Reaching Older Adults about Vision Loss

    ERIC Educational Resources Information Center

    Sussman-Skalka, Carol J.; Cimarolli, Verena R.; Stuen, Cynthia

    2006-01-01

    Vision impairment affects approximately 17% of Americans age 45 and older. Yet, 94% of adults with self-reported vision loss did not receive any type of vision rehabilitation services to help them retain independence. These findings underscore the need for promoting awareness about what can be done when vision fails. A national dissemination

  14. The Role of Organizations in Reaching Older Adults about Vision Loss

    ERIC Educational Resources Information Center

    Sussman-Skalka, Carol J.; Cimarolli, Verena R.; Stuen, Cynthia

    2006-01-01

    Vision impairment affects approximately 17% of Americans age 45 and older. Yet, 94% of adults with self-reported vision loss did not receive any type of vision rehabilitation services to help them retain independence. These findings underscore the need for promoting awareness about what can be done when vision fails. A national dissemination…

  15. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence

    PubMed Central

    Moreno-Martínez, F. Javier; Rodríguez-Rojo, Inmaculada C.

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing. PMID:26074675

  16. Applied machine vision

    SciTech Connect

    Not Available

    1984-01-01

    This book presents the papers given at a conference on robot vision. Topics considered at the conference included the link between fixed and flexible automation, general applications of machine vision, the development of a specification for a machine vision system, machine vision technology, machine vision non-contact gaging, and vision in electronics manufacturing.

  17. What Colour Is a Shadow?

    ERIC Educational Resources Information Center

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called

  18. What Colour Is a Shadow?

    ERIC Educational Resources Information Center

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

  19. The Gradual Transformation of Historical Situations: Understanding "Change and Continuity" through Colours and Timelines

    ERIC Educational Resources Information Center

    Vella, Yosanne

    2011-01-01

    The small-scale research that Yosanne Vella reports in this article was driven by concern to help pupils develop "big picture" visions of the past and to engage effectively with the idea of change as a process rather than an event. The strategy that she adopts--asking groups of students to colour in a timeline recording their judgement in response

  20. Pleiades Visions

    NASA Astrophysics Data System (ADS)

    Whitehouse, M.

    2016-01-01

    Pleiades Visions (2012) is my new musical composition for organ that takes inspiration from traditional lore and music associated with the Pleiades (Seven Sisters) star cluster from Australian Aboriginal, Native American, and Native Hawaiian cultures. It is based on my doctoral dissertation research incorporating techniques from the fields of ethnomusicology and cultural astronomy; this research likely represents a new area of inquiry for both fields. This large-scale work employs the organ's vast sonic resources to evoke the majesty of the night sky and the expansive landscapes of the homelands of the above-mentioned peoples. Other important themes in Pleiades Visions are those of place, origins, cosmology, and the creation of the world.

  1. Computer vision

    SciTech Connect

    Not Available

    1982-01-01

    This paper discusses material from areas such as artificial intelligence, psychology, computer graphics, and image processing. The intent is to assemble a selection of this material in a form that will serve both as a senior/graduate-level academic text and as a useful reference to those building vision systems. This book has a strong artificial intelligence flavour, emphasising the belief that both the intrinsic image information and the internal model of the world are important in successful vision systems. The book is organised into four parts, based on descriptions of objects at four different levels of abstraction. These are: generalised images-images and image-like entities; segmented images-images organised into subimages that are likely to correspond to interesting objects; geometric structures-quantitative models of image and world structures; relational structures-complex symbolic descriptions of image and world structures. The book contains author and subject indexes.

  2. Lambda Vision

    NASA Astrophysics Data System (ADS)

    Czajkowski, Michael

    2014-06-01

    There is an explosion in the quantity and quality of IMINT data being captured in Intelligence Surveillance and Reconnaissance (ISR) today. While automated exploitation techniques involving computer vision are arriving, only a few architectures can manage both the storage and bandwidth of large volumes of IMINT data and also present results to analysts quickly. Lockheed Martin Advanced Technology Laboratories (ATL) has been actively researching in the area of applying Big Data cloud computing techniques to computer vision applications. This paper presents the results of this work in adopting a Lambda Architecture to process and disseminate IMINT data using computer vision algorithms. The approach embodies an end-to-end solution by processing IMINT data from sensors to serving information products quickly to analysts, independent of the size of the data. The solution lies in dividing up the architecture into a speed layer for low-latent processing and a batch layer for higher quality answers at the expense of time, but in a robust and fault-tolerant way. This approach was evaluated using a large corpus of IMINT data collected by a C-130 Shadow Harvest sensor over Afghanistan from 2010 through 2012. The evaluation data corpus included full motion video from both narrow and wide area field-of-views. The evaluation was done on a scaled-out cloud infrastructure that is similar in composition to those found in the Intelligence Community. The paper shows experimental results to prove the scalability of the architecture and precision of its results using a computer vision algorithm designed to identify man-made objects in sparse data terrain.

  3. [Vision-impaired patients. Nursing diagnoses].

    PubMed

    Garca-Carpintero Muoz, M A

    2001-10-01

    The author analyzes the most habitual problems one encounters in patients suffering a visual deficit, using the NANDA diagnostic taxonomy. The author formulates and classifies these problems as well as the specific nursing treatments which should be carried out when dealing with each one of these problems. PMID:12149996

  4. Virtual Vision

    NASA Astrophysics Data System (ADS)

    Terzopoulos, Demetri; Qureshi, Faisal Z.

    Computer vision and sensor networks researchers are increasingly motivated to investigate complex multi-camera sensing and control issues that arise in the automatic visual surveillance of extensive, highly populated public spaces such as airports and train stations. However, they often encounter serious impediments to deploying and experimenting with large-scale physical camera networks in such real-world environments. We propose an alternative approach called "Virtual Vision", which facilitates this type of research through the virtual reality simulation of populated urban spaces, camera sensor networks, and computer vision on commodity computers. We demonstrate the usefulness of our approach by developing two highly automated surveillance systems comprising passive and active pan/tilt/zoom cameras that are deployed in a virtual train station environment populated by autonomous, lifelike virtual pedestrians. The easily reconfigurable virtual cameras distributed in this environment generate synthetic video feeds that emulate those acquired by real surveillance cameras monitoring public spaces. The novel multi-camera control strategies that we describe enable the cameras to collaborate in persistently observing pedestrians of interest and in acquiring close-up videos of pedestrians in designated areas.

  5. Reading aids for adults with low vision

    PubMed Central

    Virgili, Gianni; Acosta, Ruthy; Grover, Lori L; Bentley, Sharon A; Giacomelli, Giovanni

    2014-01-01

    Background The purpose of low-vision rehabilitation is to allow people to resume or to continue to perform daily living tasks, with reading being one of the most important. This is achieved by providing appropriate optical devices and special training in the use of residual-vision and low-vision aids, which range from simple optical magnifiers to high-magnification video magnifiers. Objectives To assess the effects of reading aids for adults with low vision. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to January 2013), EMBASE (January 1980 to January 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2013), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov/) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 31 January 2013. We searched the reference lists of relevant articles and used the Science Citation Index to find articles that cited the included studies and contacted investigators and manufacturers of low-vision aids. We handsearched the British Journal of Visual Impairment from 1983 to 1999 and the Journal of Visual Impairment and Blindness from 1976 to 1991. Selection criteria This review includes randomised and quasi-randomised trials in which any device or aid used for reading had been compared to another device or aid in people aged 16 or over with low vision as defined by the study investigators. Data collection and analysis At least two authors independently assessed trial quality and extracted data. Main results We included nine small studies with a cross-over-like design (181 people overall) and one study with three parallel arms (243 participants) in the review. All studies reported the primary outcome, results for reading speed. Two studies including 92 participants found moderate- or low-quality evidence suggesting that reading speed is higher with stand-mounted electronic devices or electronic devices with the camera mounted in a ‘mouse’ than with optical magnifiers, which in these trials were generally stand-mounted or, less frequently, hand-held magnifiers or microscopic lenses. In another study of 20 participants there was moderate-quality evidence that optical devices are better than head-mounted electronic devices (four types). There was low-quality evidence from three studies (93 participants) that reading using head-mounted electronic devices is slower than with stand-based electronic devices. The technology of electronic devices may have changed and improved since these studies were conducted. One study suggested no difference between a diffractive spectacle-mounted magnifier and either refractive (15 participants) or aplanatic (15 participants) magnifiers. One study of 10 people suggested that several overlay coloured filters were no better and possibly worse than a clear filter. A parallel-arm study including 243 participants with age-related macular degeneration found that custom or standard prism spectacles were no different from conventional reading spectacles, although the data did not allow precise estimates of performance to be made. Authors' conclusions There is insufficient evidence on the effect of different types of low-vision aids on reading performance. It would be necessary to investigate which patient characteristics predict performance with different devices, including costly electronic devices. Better-quality research should also focus on assessing sustained long-term use of each device. Authors of studies testing several devices on the same person should consider design and reporting issues related to their sequential presentation and to the cross-over-like study design. PMID:24154864

  6. The colour of gender stereotyping.

    PubMed

    Cunningham, Sheila J; Macrae, C Neil

    2011-08-01

    Despite legislative attempts to eliminate gender stereotyping from society, the propensity to evaluate people on the basis of their sex remains a pernicious social problem. Noting the critical interplay between cultural and cognitive factors in the establishment of stereotypical beliefs, the current investigation explored the extent to which culturally transmitted colour-gender associations (i.e., pink is for girls, blue is for boys) set the stage for the automatic activation and expression of gender stereotypes. Across six experiments, the results demonstrated that (1) consumer choice for children's goods is dominated by gender-stereotyped colours (Experiment 1); (2) colour-based stereotypic associations guide young children's behaviour (Experiment 2); (3) colour-gender associations automatically activate associated stereotypes in adulthood (Experiments 3-5); and (4) colour-based stereotypic associations bias impressions of male and female targets (Experiment 6). These findings indicate that, despite prohibitions against stereotyping, seemingly innocuous societal practices may continue to promote this mode of thought. PMID:21752009

  7. Differentiating Biological Colours with Few and Many Sensors: Spectral Reconstruction with RGB and Hyperspectral Cameras

    PubMed Central

    Garcia, Jair E.; Girard, Madeline B.; Kasumovic, Michael; Petersen, Phred; Wilksch, Philip A.; Dyer, Adrian G.

    2015-01-01

    Background The ability to discriminate between two similar or progressively dissimilar colours is important for many animals as it allows for accurately interpreting visual signals produced by key target stimuli or distractor information. Spectrophotometry objectively measures the spectral characteristics of these signals, but is often limited to point samples that could underestimate spectral variability within a single sample. Algorithms for RGB images and digital imaging devices with many more than three channels, hyperspectral cameras, have been recently developed to produce image spectrophotometers to recover reflectance spectra at individual pixel locations. We compare a linearised RGB and a hyperspectral camera in terms of their individual capacities to discriminate between colour targets of varying perceptual similarity for a human observer. Main Findings (1) The colour discrimination power of the RGB device is dependent on colour similarity between the samples whilst the hyperspectral device enables the reconstruction of a unique spectrum for each sampled pixel location independently from their chromatic appearance. (2) Uncertainty associated with spectral reconstruction from RGB responses results from the joint effect of metamerism and spectral variability within a single sample. Conclusion (1) RGB devices give a valuable insight into the limitations of colour discrimination with a low number of photoreceptors, as the principles involved in the interpretation of photoreceptor signals in trichromatic animals also apply to RGB camera responses. (2) The hyperspectral camera architecture provides means to explore other important aspects of colour vision like the perception of certain types of camouflage and colour constancy where multiple, narrow-band sensors increase resolution. PMID:25965264

  8. Colour blindness of the movement-detecting system of the spider Cupiennius salei.

    PubMed

    Orlando, Eva; Schmid, Axel

    2011-02-15

    The nocturnal wandering spider Cupiennius salei has one pair of principal eyes and three pairs of secondary eyes located on the prosoma, which differ in both morphology and function. Their spectral sensitivity, measured with intracellular recordings, is due to three different types of photoreceptors with absorbance maxima in the mid-range of the spectrum, at 480 nm and 520 nm and in the UV at 360 nm. Based on these physiological data colour vision might be possible. In the present study, the ability to discriminate coloured moving stimuli from grey backgrounds was tested. The perception of moving coloured stripes in front of backgrounds with 29 different grey levels was measured by using extracellular recordings from the anterior median eye muscles as a monitoring system. Each of these eyes has two muscles, which increase their activity when moving stimuli are presented in front of a secondary eye. This variation in eye muscle activity can be recorded extracellulary in a living spider using a single channel telemetry device. If colour perception exists, the animal should be able to detect a moving coloured stripe in front of any grey level. Blue, green and red stripes were used as moving stimuli, in front of all 29 grey backgrounds. The results indicate that C. salei is not able to discriminate the coloured stimuli from distinct shades of grey. It is therefore evident that the movement-detecting system in this spider appears to be colour blind. PMID:21270302

  9. The perception of isoluminant coloured stimuli of amblyopic eye and defocused eye

    NASA Astrophysics Data System (ADS)

    Krumina, Gunta; Ozolinsh, Maris; Ikaunieks, Gatis

    2008-09-01

    In routine eye examination the visual acuity usually is determined using standard charts with black letters on a white background, however contrast and colour are important characteristics of visual perception. The purpose of research was to study the perception of isoluminant coloured stimuli in the cases of true and simulated amlyopia. We estimated difference in visual acuity with isoluminant coloured stimuli comparing to that for high contrast black-white stimuli for true amblyopia and simulated amblyopia. Tests were generated on computer screen. Visual acuity was detected using different charts in two ways: standard achromatic stimuli (black symbols on a white background) and isoluminant coloured stimuli (white symbols on a yellow background, grey symbols on blue, green or red background). Thus isoluminant tests had colour contrast only but had no luminance contrast. Visual acuity evaluated with the standard method and colour tests were studied for subjects with good visual acuity, if necessary using the best vision correction. The same was performed for subjects with defocused eye and with true amblyopia. Defocus was realized with optical lenses placed in front of the normal eye. The obtained results applying the isoluminant colour charts revealed worsening of the visual acuity comparing with the visual acuity estimated with a standard high contrast method (black symbols on a white background).

  10. "Colour constancy" in Mondrian patterns: a partial cancellation of physical chromaticity shifts by simultaneous contrast.

    PubMed

    Valberg, A; Lange-Malecki, B

    1990-01-01

    Edwin Land's Mondrian demonstrations (Land 1977, 1983, 1986a) are striking examples that the perceived colours of objects are largely independent of the chromaticity of the light incident upon them. Attempts to implement this independence in artificial vision systems have renewed interest in colour constancy and contrast, and the explanation of these phenomena in the Retinex theory. We use colour matches to demonstrate that departures from "colour constancy" are large and that it is possible to obtain the same colour shifts when the complex Mondrian pattern is replaced by a homogeneous grey field surrounding a test patch. A given patch has the same colour when surrounded by the Mondrian as when set in a grey background, provided that the grey represents the spatially weighted average of the Mondrian. Neither the colour shifts nor the equivalence of this neutral surround are correctly predicted by the Retinex theory. The phenomenon of partial cancellation of physical chromaticity shifts with changes of illuminant thus reduces to one of simultaneous contrast and adaptation where a spatio-chromatic and luminance average over a Mondrian pattern is the same as for a grey surround. Experiments with simultaneous contrast demonstrate that spatial weighting factors need to be applied in computations of the effect of the separate areas of a complex Mondrian pattern. PMID:2336796

  11. Vision Therapy News Backgrounder.

    ERIC Educational Resources Information Center

    American Optometric Association, St. Louis, MO.

    The booklet provides an overview on vision therapy to aid writers, editors, and broadcasters help parents, teachers, older adults, and all consumers learn more about vision therapy. Following a description of vision therapy or vision training, information is provided on how and why vision therapy works. Additional sections address providers of

  12. Artful visions.

    PubMed

    Wade, Nicholas J

    2007-01-01

    Visual artists and visual scientists are often concerned with examining the same spatial phenomena, but the methods they adopt differ radically. Scientists try to discover new facts regarding old phenomena; they rarely discover new phenomena but different conditions under which the old ones operate (perhaps using some novel apparatus for generating stimuli). Artists are concerned with arranging phenomena in a manner that has not been seen before, or perhaps to increase the spectators' awareness of the phenomena. This typically involves complicating the effects rather than simplifying pattern elements. Thus, scientists rarefy and isolate phenomena to control them in the laboratory, whereas artists embrace complexity and manipulate phenomena intuitively. The differences in method have resulted in divergent vocabularies for describing similar effects, and the two approaches can appear more disparate than their phenomenal commonality would suggest. It could be argued that for spatial vision, prior to the advent of computer graphics, visual scientists have not represented adequately the subject matter of their own enquiry; this want was supplied by visual artists. Not only have artists provided more engaging examples of spatial phenomena, but they have also enhanced their range in ways that are scientifically novel. The opposite argument applies to motion perception, where scientists developed techniques that were eagerly adopted in the arts. The interactions between art and both spatial and motion vision were influenced by instruments invented in the early nineteenth century for manipulating the representation of space and time - the stereoscope and the stroboscopic disc. PMID:18073050

  13. Quebec model for low vision rehabilitation.

    PubMed

    Robillard, Nicole; Overbury, Olga

    2006-06-01

    The increase in longevity (and secondary morbidity) in the Quebec population adds social and financial pressure to society, as it does elsewhere in Canada and in many western countries. This article gives a brief history of the evolution of vision rehabilitation services in Quebec and describes how services are provided for people with low vision throughout the province. Although numerous groups, associations, centres, and resources are available to assist people with vision impairments, such as the Canadian National Institute for the Blind-Qubec, the majority of visual rehabilitation services are provided by government-sponsored rehabilitation centres, namely the Centres rgionaux de radaptation en dficience physique that are located strategically throughout the province. Low vision clinical evaluations in these centres are shared by 36 optometrists throughout the province. Between 5 and 7 ophthalmologists are involved in low vision care, half in university-affiliated hospitals, primarily in Montreal. There may be delays of up to 6 months to be seen in a funded low vision clinic. Statistics obtained from la Rgie de l'assurance maladie du Qubec show that there are approximately 8,000 requests for low vision aids every year, and that 80% of clients retain at least some level of visual function. Services are covered by Medicare and low vision aids are provided at no cost, although ophthalmologists cannot prescribe low vision aids through the Medicare-funded system. We must ensure that the capacity of our system continues to provide adequately for clientele in the future. PMID:16767193

  14. The colour of an avifauna: A quantitative analysis of the colour of Australian birds.

    PubMed

    Delhey, Kaspar

    2015-01-01

    Animal coloration is a poorly-understood aspect of phenotypic variability. Here I expand initial studies of the colour gamut of birds by providing the first quantitative description of the colour variation of an entire avifauna: Australian landbirds (555 species). The colour of Australian birds occupies a small fraction (19%) of the entire possible colour space and colour variation is extremely uneven. Most colours are unsaturated, concentrated in the centre of colour space and based on the deposition of melanins. Other mechanisms of colour production are less common but account for larger portions of colour space and for most saturated colours. Male colours occupy 45-25% more colour space than female colours, indicating that sexual dichromatism translates into a broader range of male colours. Male-exclusive colours are often saturated, at the edge of chromatic space, and have most likely evolved for signalling. While most clades of birds occupy expected or lower-than-expected colour volumes, parrots and cockatoos (Order Psittaciformes) occupy a much larger volume than expected. This uneven distribution of colour variation across mechanisms of colour production, sexes and clades is probably shared by avifaunas in other parts of the world, but this remains to be tested with comparable data. PMID:26679370

  15. The colour of an avifauna: A quantitative analysis of the colour of Australian birds

    PubMed Central

    Delhey, Kaspar

    2015-01-01

    Animal coloration is a poorly-understood aspect of phenotypic variability. Here I expand initial studies of the colour gamut of birds by providing the first quantitative description of the colour variation of an entire avifauna: Australian landbirds (555 species). The colour of Australian birds occupies a small fraction (19%) of the entire possible colour space and colour variation is extremely uneven. Most colours are unsaturated, concentrated in the centre of colour space and based on the deposition of melanins. Other mechanisms of colour production are less common but account for larger portions of colour space and for most saturated colours. Male colours occupy 45–25% more colour space than female colours, indicating that sexual dichromatism translates into a broader range of male colours. Male-exclusive colours are often saturated, at the edge of chromatic space, and have most likely evolved for signalling. While most clades of birds occupy expected or lower-than-expected colour volumes, parrots and cockatoos (Order Psittaciformes) occupy a much larger volume than expected. This uneven distribution of colour variation across mechanisms of colour production, sexes and clades is probably shared by avifaunas in other parts of the world, but this remains to be tested with comparable data. PMID:26679370

  16. Ecological genomics in full colour.

    PubMed

    Hohenlohe, Paul A

    2014-11-01

    Colour patterns in animals have long offered an opportunity to observe adaptive traits in natural populations. Colour plays myriad roles in interactions within and among species, from reproductive signalling to predator avoidance, leading to multiple targets of natural and sexual selection and opportunities for diversification. Understanding the genetic and developmental underpinnings of variation in colour promises a fuller understanding of these evolutionary processes, but the path to unravelling these connections can be arduous. The advent of genomic techniques suitable for nonmodel organisms is now beginning to light the way. Two new studies in this issue of Molecular Ecology use genomic sequencing of laboratory crosses to map colour traits in cichlid fishes, a remarkably diverse group in which coloration has played a major role in diversification. They illustrate how genomic approaches, specifically RAD sequencing, can rapidly identify both simple and more complex genetic variation underlying ecologically important traits. In the first, Henning et al. () detect a single locus that appears to control in a Mendelian fashion the presence of horizontal stripes, a trait that has evolved in numerous cichlid lineages. In the second, Albertson et al. () identify several genes and epistatic interactions affecting multiple colour traits, as well as a novel metric describing integration across colour traits. Albertson et al. () go further, by quantifying differential expression of parental alleles at a candidate locus and by relating differentiation among natural populations at mapped loci to trait divergence. Herein lies the promise of ecological genomics - efficiently integrating genetic mapping of phenotypes with population genomic data to both identify functional genes and unravel their evolutionary history. These studies offer guidance on how genomic techniques can be tailored to a research question or study system, and they also add to the growing body of empirical examples addressing basic questions about how ecologically important traits evolve in natural populations. PMID:25330852

  17. Neuronal morphology of biological vision: a basis for machine vision (Proceedings Only)

    NASA Astrophysics Data System (ADS)

    Gupta, Madan M.

    1992-03-01

    In this paper, we are concerned with the study of the biological vision system and the emulation of some of its mathematical functions, in both the retinal and visual cortex, for the development of a robust computer vision system. This field of research is not only intriguing, but offers a great challenge to systems scientists in the development of functional algorithms. These functional algorithms can be generalized for further studies for fields such as signal processing, control systems and image processing. Our studies are heavily dependent on the use of neuronal layers and the generalized receptive fields. Building blocks of such neuronal layers and receptive fields may lead to the design of better sensors and better computer vision systems. It is hoped that these studies will lead to the development of better artificial vision systems with applications to vision prosthesis for visually impaired persons, robotic vision, medical imaging, medical sensors, industrial automation, remote sensing, space stations and ocean exploration.

  18. Visual impairment in the hearing impaired students

    PubMed Central

    Gogate, Parikshit; Rishikeshi, Nikhil; Mehata, Reshma; Ranade, Satish; Kharat, Jitesh; Deshpande, Madan

    2009-01-01

    Background: Ocular problems are more common in children with hearing problems than in normal children. Neglected visual impairment could aggravate educational and social disability. Aim: To detect and treat visual impairment, if any, in hearing-impaired children. Setting and Design: Observational, clinical case series of hearing-impaired children in schools providing special education. Materials and Methods: Hearing-impaired children in selected schools underwent detailed visual acuity testing, refraction, external ocular examination and fundoscopy. Ocular motility testing was also performed. Teachers were sensitized and trained to help in the assessment of visual acuity using Snellen's E charts. Refractive errors and squint were treated as per standard practice. Statistical Analysis: Excel software was used for data entry and SSPS for analysis. Results: The study involved 901 hearing-impaired students between four and 21 years of age, from 14 special education schools. A quarter of them (216/901, 24%) had ocular problems. Refractive errors were the most common morbidity 167(18.5%), but only 10 children were using appropriate spectacle correction at presentation. Fifty children had visual acuity less than 20/80 at presentation; after providing refractive correction, this number reduced to three children, all of whom were provided low-vision aids. Other common conditions included strabismus in 12 (1.3%) children, and retinal pigmentary dystrophy in five (0.6%) children. Conclusion: Ocular problems are common in hearing-impaired children. Screening for ocular problems should be made mandatory in hearing-impaired children, as they use their visual sense to compensate for the poor auditory sense. PMID:19861747

  19. Robot Vision

    NASA Technical Reports Server (NTRS)

    Sutro, L. L.; Lerman, J. B.

    1973-01-01

    The operation of a system is described that is built both to model the vision of primate animals, including man, and serve as a pre-prototype of possible object recognition system. It was employed in a series of experiments to determine the practicability of matching left and right images of a scene to determine the range and form of objects. The experiments started with computer generated random-dot stereograms as inputs and progressed through random square stereograms to a real scene. The major problems were the elimination of spurious matches, between the left and right views, and the interpretation of ambiguous regions, on the left side of an object that can be viewed only by the left camera, and on the right side of an object that can be viewed only by the right camera.

  20. Vision Screening

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Visi Screen OSS-C, marketed by Vision Research Corporation, incorporates image processing technology originally developed by Marshall Space Flight Center. Its advantage in eye screening is speed. Because it requires no response from a subject, it can be used to detect eye problems in very young children. An electronic flash from a 35 millimeter camera sends light into a child's eyes, which is reflected back to the camera lens. The photorefractor then analyzes the retinal reflexes generated and produces an image of the child's eyes, which enables a trained observer to identify any defects. The device is used by pediatricians, day care centers and civic organizations that concentrate on children with special needs.

  1. Binocular Vision

    PubMed Central

    Blake, Randolph; Wilson, Hugh

    2010-01-01

    This essay reviews major developments empirical and theoretical in the field of binocular vision during the last 25 years. We limit our survey primarily to work on human stereopsis, binocular rivalry and binocular contrast summation, with discussion where relevant of single-unit neurophysiology and human brain imaging. We identify several key controversies that have stimulated important work on these problems. In the case of stereopsis those controversies include position versus phase encoding of disparity, dependence of disparity limits on spatial scale, role of occlusion in binocular depth and surface perception, and motion in 3D. In the case of binocular rivalry, controversies include eye versus stimulus rivalry, role of top-down influences on rivalry dynamics, and the interaction of binocular rivalry and stereopsis. Concerning binocular contrast summation, the essay focuses on two representative models that highlight the evolving complexity in this field of study. PMID:20951722

  2. The Secret World of Shrimps: Polarisation Vision at Its Best

    PubMed Central

    Kleinlogel, Sonja; White, Andrew G.

    2008-01-01

    Background Animal vision spans a great range of complexity, with systems evolving to detect variations in light intensity, distribution, colour, and polarisation. Polarisation vision systems studied to date detect one to four channels of linear polarisation, combining them in opponent pairs to provide intensity-independent operation. Circular polarisation vision has never been seen, and is widely believed to play no part in animal vision. Methodology/Principal Findings Polarisation is fully measured via Stokes' parameters—obtained by combined linear and circular polarisation measurements. Optimal polarisation vision is the ability to see Stokes' parameters: here we show that the crustacean Gonodactylus smithii measures the exact components required. Conclusions/Significance This vision provides optimal contrast-enhancement and precise determination of polarisation with no confusion states or neutral points—significant advantages. Linear and circular polarisation each give partial information about the polarisation of light—but the combination of the two, as we will show here, results in optimal polarisation vision. We suggest that linear and circular polarisation vision not be regarded as different modalities, since both are necessary for optimal polarisation vision; their combination renders polarisation vision independent of strongly linearly or circularly polarised features in the animal's environment. PMID:18478095

  3. Measuring grinding surface roughness based on the sharpness evaluation of colour images

    NASA Astrophysics Data System (ADS)

    Huaian, Y. I.; Jian, L. I. U.; Enhui, L. U.; Peng, A. O.

    2016-02-01

    Current machine vision-based detection methods for metal surface roughness mainly use the grey values of images for statistical analysis but do not make full use of the colour information and ignore the subjective judgment of the human vision system. To address these problems, this paper proposes a method to measure surface roughness through the sharpness evaluation of colour images. Based on the difference in sharpness of virtual images of colour blocks that are formed on grinding surfaces with different roughness, an algorithm for evaluating the sharpness of colour images that is based on the difference of the RGB colour space was used to develop a correlation model between the sharpness and the surface roughness. The correlation model was analysed under two conditions: constant illumination and varying illumination. The effect of the surface textures of the grinding samples on the image sharpness was also considered, demonstrating the feasibility of the detection method. The results show that the sharpness is strongly correlated with the surface roughness; when the illumination and the surface texture have the same orientation, the sharpness clearly decreases with increasing surface roughness. Under varying illumination, this correlation between the sharpness and surface roughness was highly robust, and the sharpness of each virtual image increased linearly with the illumination. Relative to the detection method for surface roughness using gray level co-occurrence matrix or artificial neural network, the proposed method is convenient, highly accurate and has a wide measurement range.

  4. Low Vision Aids and Low Vision Rehabilitation

    MedlinePLUS

    ... The future will offer even more solutions. Newer technology for low vision aids While low vision devices ... magnifiers have long been the standard in assistive technology, advances in consumer electronics are also improving quality ...

  5. Filtering and polychromatic vision in mantis shrimps: themes in visible and ultraviolet vision

    PubMed Central

    Cronin, Thomas W.; Bok, Michael J.; Marshall, N. Justin; Caldwell, Roy L.

    2014-01-01

    Stomatopod crustaceans have the most complex and diverse assortment of retinal photoreceptors of any animals, with 16 functional classes. The receptor classes are subdivided into sets responsible for ultraviolet vision, spatial vision, colour vision and polarization vision. Many of these receptor classes are spectrally tuned by filtering pigments located in photoreceptors or overlying optical elements. At visible wavelengths, carotenoproteins or similar substances are packed into vesicles used either as serial, intrarhabdomal filters or lateral filters. A single retina may contain a diversity of these filtering pigments paired with specific photoreceptors, and the pigments used vary between and within species both taxonomically and ecologically. Ultraviolet-filtering pigments in the crystalline cones serve to tune ultraviolet vision in these animals as well, and some ultraviolet receptors themselves act as birefringent filters to enable circular polarization vision. Stomatopods have reached an evolutionary extreme in their use of filter mechanisms to tune photoreception to habitat and behaviour, allowing them to extend the spectral range of their vision both deeper into the ultraviolet and further into the red. PMID:24395960

  6. Structural colour in Chondrus crispus.

    PubMed

    Chandler, Chris J; Wilts, Bodo D; Vignolini, Silvia; Brodie, Juliet; Steiner, Ullrich; Rudall, Paula J; Glover, Beverley J; Gregory, Thomas; Walker, Rachel H

    2015-01-01

    The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector. PMID:26139470

  7. String formation beyond leading colour

    NASA Astrophysics Data System (ADS)

    Christiansen, Jesper R.; Skands, Peter Z.

    2015-08-01

    We present a new model for the hadronisation of multi-parton systems, in which colour correlations beyond leading N C are allowed to influence the formation of confining potentials (strings). The multiplet structure of SU(3) is combined with a minimisation of the string potential energy, to decide between which partons strings should form, allowing also for "baryonic" configurations (e.g., two colours can combine coherently to form an anticolour). In e + e -collisions, modifications to the leading-colour picture are small, suppressed by both colour and kinematics factors. But in pp collisions, multi-parton interactions increase the number of possible subleading connections, counteracting their naive 1/ N {/C 2} suppression. Moreover, those that reduce the overall string lengths are kinematically favoured. The model, which we have implemented in the PYTHIA 8 generator, is capable of reaching agreement not only with the important < p ?> ( n charged) distribution but also with measured rates (and ratios) of kaons and hyperons, in both ee and pp collisions. Nonetheless, the shape of their p ? spectra remains challenging to explain.

  8. Structural colour in Chondrus crispus

    NASA Astrophysics Data System (ADS)

    Chandler, Chris J.; Wilts, Bodo D.; Vignolini, Silvia; Brodie, Juliet; Steiner, Ullrich; Rudall, Paula J.; Glover, Beverley J.; Gregory, Thomas; Walker, Rachel H.

    2015-07-01

    The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector.

  9. Bullying in German Adolescents: Attending Special School for Students with Visual Impairment

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2011-01-01

    The present study analysed bullying in German adolescents with and without visual impairment. Ninety-eight adolescents with vision loss from schools for students with visual impairment, of whom 31 were blind and 67 had low vision, were compared with 98 sighted peers using a matched-pair design. Students with low vision reported higher levels of

  10. Segmentation of Colour Layers in Historical Maps Based on Hierarchical Colour Sampling

    NASA Astrophysics Data System (ADS)

    Leyk, Stefan

    A colour image segmentation (CIS) process for scanned historical maps is presented to overcome common problems associated with segmentation of old documents such as (1) variation in colour values of the same colour layer within one map page, (2) differences in typical colour values between homogeneous areas and thin line-work, which belong both to the same colour layer, and (3) extensive parameterization that results in a lack of robustness. The described approach is based on a two-stage colour layer prototype search using a constrained sampling design. Global colour layer prototypes for the identification of homogeneous regions are derived based on colour similarity to the most extreme colour layer values identified in the map page. These global colour layer prototypes are continuously adjusted using relative distances between prototype positions in colour space until a reliable sample is collected. Based on this sample colour layer seeds and directly connected neighbors of the same colour layer are determined resulting in the extraction of homogeneous colour layer regions. In the next step the global colour layer prototypes are recomputed using a new sample of colour values along the margins of identified homogeneous coloured regions. This sampling step derives representative prototypes of map layer sections that deviate significantly from homogeneous regions of the same layers due to bleaching, mixed or false colouring and ageing of the original scanned documents. A spatial expansion process uses these adjusted prototypes as start criterion to assign the remaining colour layer parts. The approach shows high robustness for map documents that suffer from low graphical quality indicating some potential for general applicability due to its simplicity and the limited need for preliminary information. The only input required is the colours and number of colour layers present in the map.

  11. Colour As a Signal for Entraining the Mammalian Circadian Clock

    PubMed Central

    Walmsley, Lauren; Hanna, Lydia; Mouland, Josh; Martial, Franck; West, Alexander; Smedley, Andrew R.; Bechtold, David A.; Webb, Ann R.; Lucas, Robert J.; Brown, Timothy M.

    2015-01-01

    Twilight is characterised by changes in both quantity (irradiance) and quality (colour) of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blueyellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision. PMID:25884537

  12. An RGB Approach to Prismatic Colours

    ERIC Educational Resources Information Center

    Theilmann, Florian; Grusche, Sascha

    2013-01-01

    Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well

  13. An RGB Approach to Prismatic Colours

    ERIC Educational Resources Information Center

    Theilmann, Florian; Grusche, Sascha

    2013-01-01

    Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well…

  14. Biological Components of Colour Preference in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

    2010-01-01

    Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in

  15. Biological Components of Colour Preference in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

    2010-01-01

    Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in…

  16. Physiology and Psychology of Vision and Its Disorders: A Review

    PubMed Central

    Moschos, Marilita M

    2014-01-01

    The purpose of this review is to bring together to the physiology and psychology of vision and to analyze, based on our own data and on the available literature, the relationship between sight loss and individual reactions. As recent treatments for depression are often effective and have few side-effects, ophthalmologists should consider referral for treatment of depression in patients suffering from vision impairment. For this reason, vision rehabilitation should be more readily available and recommended. PMID:25741524

  17. The Seven Module Curriculum on Aging, Vision Loss and Independent Living Skills. A Training Model To Teach Community Outreach Workers To Train Elderly Blind and Visually Impaired American Indians Independent Living Skills: Focus on Family Rehabilitation.

    ERIC Educational Resources Information Center

    Orr, Alberta L.; Kaarlela, Ruth

    This curriculum was designed to train approximately 250 community health representatives (CHRs), to teach visually impaired and blind Indian elders and their families necessary independent living skills. The curriculum aims to sensitize CHRs to the impact of visual impairment upon elderly persons and their families, and to provide basic…

  18. Visual Memory for Objects Following Foveal Vision Loss

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Herbik, Anne; Hofmller, Wolfram; Hoffmann, Michael B.; Pollmann, Stefan

    2015-01-01

    Allocation of visual attention is crucial for encoding items into visual long-term memory. In free vision, attention is closely linked to the center of gaze, raising the question whether foveal vision loss entails suboptimal deployment of attention and subsequent impairment of object encoding. To investigate this question, we examined visual

  19. Visual Memory for Objects Following Foveal Vision Loss

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Herbik, Anne; Hofmüller, Wolfram; Hoffmann, Michael B.; Pollmann, Stefan

    2015-01-01

    Allocation of visual attention is crucial for encoding items into visual long-term memory. In free vision, attention is closely linked to the center of gaze, raising the question whether foveal vision loss entails suboptimal deployment of attention and subsequent impairment of object encoding. To investigate this question, we examined visual…

  20. 75 FR 9477 - Qualification of Drivers; Exemption Applications; Vision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-02

    ... physically qualified under 49 CFR 391.41; (2) that each individual provides a copy of the ophthalmologist's... specified at 49 CFR 391.41(b)(10) and that the vision impairment is stable. In addition, a review of each... exempt these 19 individuals from the vision requirement in 49 CFR 391.41(b)(10). The final decision...

  1. Adolescents with Low Vision: Perceptions of Driving and Nondriving

    ERIC Educational Resources Information Center

    Sacks, Sharon Zell; Rosenblum, L. Penny

    2006-01-01

    Two studies examined how adolescents with low vision perceive their ability to drive. The results of both studies indicated similarities in the participants' responses with respect to knowledge of visual impairment, information about options for driving with low vision, frustrations and obstacles imposed by not being able to drive, and independent

  2. Prentice Medal Lecture 2013: Visual Accessibility: A Challenge for Low-Vision Research

    PubMed Central

    Legge, Gordon E.

    2014-01-01

    Low vision may be defined as any chronic form of vision impairment, not correctable by glasses or contact lenses, that adversely affects everyday function. Visual accessibility refers to factors that make an environment, device or display usable by vision. In this article, I discuss the concept of visual accessibility with special reference to low vision. What role can vision science play in enhancing visual accessibility for people with low vision? I propose that greater efforts to embed low-vision research in real-world contexts and collaboration with other disciplines will accelerate progress. I describe examples from my current research projects on architectural accessibility and reading accessibility. PMID:24978657

  3. Colour annealing - a toy model of colour reconnections

    SciTech Connect

    Sandhoff, Marisa; Skands, Peter; /Fermilab

    2005-12-01

    We present a simple toy model for colour reconnections at the nonperturbative level. The model resembles an annealing-type algorithm and is applicable to any collider and process type, though we argue for a possible enhancement of the effect in hadron-hadron collisions. We present a simple application and study of the consequences for semileptonic t{bar t} events at the Tevatron.

  4. International computer vision directory

    SciTech Connect

    Flora, P.C.

    1986-01-01

    This book contains information on: computerized automation technologies. State-of-the-art computer vision systems for many areas of industrial use are covered. Other topics discussed include the following automated inspection systems; robot/vision systems; vision process control; cameras (vidicon and solid state); vision peripherals and components; and pattern processor.

  5. Ultraviolet Light: Some Considerations for Vision Stimulation.

    ERIC Educational Resources Information Center

    Knowlton, Marie

    1986-01-01

    The article examines evidence of visual impairment caused by excessive amounts of ultraviolet (UV) light. Among considerations when using a source of UV light for vision stimulation are the position of the child and teacher, use of window glass filters or protective glasses, and careful recordkeeping of all UV stimulation. (Author/JW)[

  6. Characterisation of the n-colour printing process using the spot colour overprint model.

    PubMed

    Deshpande, Kiran; Green, Phil; Pointer, Michael R

    2014-12-29

    This paper is aimed at reproducing the solid spot colours using the n-colour separation. A simplified numerical method, called as the spot colour overprint (SCOP) model, was used for characterising the n-colour printing process. This model was originally developed for estimating the spot colour overprints. It was extended to be used as a generic forward characterisation model for the n-colour printing process. The inverse printer model based on the look-up table was implemented to obtain the colour separation for n-colour printing process. Finally the real-world spot colours were reproduced using 7-colour separation on lithographic offset printing process. The colours printed with 7 inks were compared against the original spot colours to evaluate the accuracy. The results show good accuracy with the mean CIEDE2000 value between the target colours and the printed colours of 2.06. The proposed method can be used successfully to reproduce the spot colours, which can potentially save significant time and cost in the printing and packaging industry. PMID:25607147

  7. Carotenoids need structural colours to shine

    PubMed Central

    Shawkey, Matthew D; Hill, Geoffrey E

    2005-01-01

    The bright colours of feathers are among the most striking displays in nature and are frequently used as sexual signals. Feathers can be coloured by pigments or by ordered tissue, and these mechanisms have traditionally been treated as distinct modes of display. Here we show that some yellow plumage colour is created both by reflection of light from white structural tissue and absorption of light by carotenoids. Thus, structural components of feathers contribute substantially to yellow carotenoid displays, but the effect of variation in structural components on variation in colour displays is, to our knowledge, unstudied. The presence of structural colour in some carotenoid-based colour displays will have to be considered in studies of colour signalling. PMID:17148144

  8. Colour dependence of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Giese, R. H.; Hanner, M. S.; Leinert, C.

    1973-01-01

    Colour models of the zodiacal light in the ecliptic have been calculated for both dielectric and metallic particles in the sub-micron and micron size range. Two colour ratios were computed, a blue ratio and a red ratio. The models with a size distribution proportional to s to the -2.5 power ds (where s is the particle radius) generally show a colour close to the solar colour and almost independent of elongation. Especially in the blue colour ratio there is generally no significant dependence on the lower cutoff size (0.1-1 micron). The main feature of absorbing particles is a reddening at small elongations. The models for size distributions proportional to s to the -4 power ds show larger departures from solar colour and more variation with model parameters. Colour measurements, including red and near infra-red, therefore are useful to distinguish between flat and steep size spectra and to verify the presence of slightly absorbing particles.

  9. Matrix models and graph colouring

    NASA Astrophysics Data System (ADS)

    Cicuta, Giovanni M.; Molinari, Luca; Montaldi, Emilio

    1993-06-01

    We study an edge-colouring problem on random planar graphs which is one of the simplest vertex models that may be analyzed by standard methods of large N matrix models. The main features of the saddle point solution and its critical behaviour are described. At the critical value of the coupling gcr the eigen value density u(?)M is found to vanish at the border of the support as ?-a2/3.

  10. A Program for Visually Impaired Children.

    ERIC Educational Resources Information Center

    Naples, Victor J.; And Others

    Disseminated by the Ohio State Department of Education, the booklet explains how to organize programs for the visually handicapped according to the vision center concept, and describes currently available state-sponsored services for the visually impaired. Suggested philosophy and goals of programs for the visually impaired are identified, along

  11. The Physical Environment and the Visually Impaired.

    ERIC Educational Resources Information Center

    Braf, Per-Gunnar

    Reported are results of a project carried out at the Swedish Institute for the Handicapped to determine needs of the visually impaired in the planning and adaptation of buildings and other forms of physical environment. Chapter 1 considers implications of impaired vision and includes definitions, statistics, and problems of the visually impaired…

  12. Colourings and preservatives in food.

    PubMed

    Denner, W H

    1984-12-01

    Colours and preservatives are only two of the many classes of additives in food but they are of interest because many reported cases of sensitivity involve these two groups of substances. Preservatives present the greatest potential health hazard being, by definition, biologically active. Colours and other additives are required to perform a technological function whilst remaining as biologically inert as possible. Food additives are controlled by the Food and Drugs Act 1955 on the basis of advice from the Food Advisory Committee (FAC). Lists of the permitted preservatives and colourings are available, together with details of restrictions on their uses; this information is continually being updated. Food labelling regulations mean that some information about additives can be determined from the labelling--but even if an additive is not listed on the package, one cannot always assume that it is not present in the product, since additives coming through in the original ingredients need not always be listed. Other exemptions also exist, so there can be no absolute certainty about the presence, or absence, of a specific additive. That information can only be obtained by contacting the manufacturer. PMID:6526689

  13. Raven's Coloured Progressive Matrices as a Measure of Cognitive Functioning in Cerebral Palsy

    ERIC Educational Resources Information Center

    Pueyo, R.; Junque, C.; Vendrell, P.; Narberhaus, A.; Segarra, D.

    2008-01-01

    Background: Cognitive dysfunction is frequent in Cerebral Palsy (CP). CP motor impairment and associated speech deficits often hinder cognitive assessment, with the result being that not all CP studies consider cognitive dysfunction. Raven's Coloured Progressive Matrices is a simple, rapid test which can be used in persons with severe motor

  14. Raven's Coloured Progressive Matrices as a Measure of Cognitive Functioning in Cerebral Palsy

    ERIC Educational Resources Information Center

    Pueyo, R.; Junque, C.; Vendrell, P.; Narberhaus, A.; Segarra, D.

    2008-01-01

    Background: Cognitive dysfunction is frequent in Cerebral Palsy (CP). CP motor impairment and associated speech deficits often hinder cognitive assessment, with the result being that not all CP studies consider cognitive dysfunction. Raven's Coloured Progressive Matrices is a simple, rapid test which can be used in persons with severe motor…

  15. Learning to Look: A Handbook for Parents of Low Vision Infants and Young Children.

    ERIC Educational Resources Information Center

    Heiner, Donna

    Specific and understandable suggestions are offered to parents of severely visually impaired children who have or may have the capacity to learn visually. Parents can assist children with even a small amount of vision to develop that vision from an early age. Vision development begins by ensuring that the child receives appropriate medical and

  16. Visual modelling suggests a weak relationship between the evolution of ultraviolet vision and plumage coloration in birds.

    PubMed

    Lind, O; Delhey, K

    2015-03-01

    Birds have sophisticated colour vision mediated by four cone types that cover a wide visual spectrum including ultraviolet (UV) wavelengths. Many birds have modest UV sensitivity provided by violet-sensitive (VS) cones with sensitivity maxima between 400 and 425 nm. However, some birds have evolved higher UV sensitivity and a larger visual spectrum given by UV-sensitive (UVS) cones maximally sensitive at 360-370 nm. The reasons for VS-UVS transitions and their relationship to visual ecology remain unclear. It has been hypothesized that the evolution of UVS-cone vision is linked to plumage colours so that visual sensitivity and feather coloration are 'matched'. This leads to the specific prediction that UVS-cone vision enhances the discrimination of plumage colours of UVS birds while such an advantage is absent or less pronounced for VS-bird coloration. We test this hypothesis using knowledge of the complex distribution of UVS cones among birds combined with mathematical modelling of colour discrimination during different viewing conditions. We find no support for the hypothesis, which, combined with previous studies, suggests only a weak relationship between UVS-cone vision and plumage colour evolution. Instead, we suggest that UVS-cone vision generally favours colour discrimination, which creates a nonspecific selection pressure for the evolution of UVS cones. PMID:25664902

  17. Personal and Family Stress in Individuals with Diabetes and Vision Loss.

    ERIC Educational Resources Information Center

    Bernbaum, Marla; And Others

    1993-01-01

    Assessed intrapersonal distress and impact of diabetes and vision impairment on marital functioning. Found significant degrees of intrapersonal distress and compromised family functioning. Of 18 subjects in committed relationship at onset of vision impairment, 9 later separated. Totally blind subjects were at greater risk for separation than were

  18. Put on that colour, it fits your emotion: Colour appropriateness as a function of expressed emotion.

    PubMed

    Dael, Nele; Perseguers, Marie-Noëlle; Marchand, Cynthia; Antonietti, Jean-Philippe; Mohr, Christine

    2016-08-01

    People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have particularly strong affective connotations. To test whether colour choices can be driven by emotion, we investigated whether and how colour hue, brightness, and saturation are systematically associated with bodily expressions of positive (joy) and negative (fear) emotions. Twenty-five non-colour-blind participants viewed videos of these expressions and selected for each video the most appropriate colour using colour sliders providing values for hue, brightness, and saturation. The overall colour choices were congruent with the expressed emotion-that is, participants selected brighter and more saturated colours for joy expressions than for fear expressions. Also, colours along the red-yellow spectrum were deemed more appropriate for joy expressions and cyan-bluish hues for fear expressions. The current study adds further support to the role of emotion in colour choices by (a) showing that emotional information is spontaneously used in an unconstrained choice setting, (b) extending to ecologically valid stimuli occurring in everyday encounters (dressed bodies), and PMID:26339950

  19. Structural colour: Colour mixing in wing scales of a butterfly

    NASA Astrophysics Data System (ADS)

    Vukusic, P.; Sambles, J. R.; Lawrence, C. R.

    2000-03-01

    Green coloration in the animal kingdom, as seen in birds' feathers and reptile integument, is often an additive mixture of structurally effected blue and pigmentary yellow. Here we investigate the origin of the bright green coloration of the wing scales of the Indonesian male Papilio palinurus butterfly, the microstructure of which generates an extraordinary combination of both yellow and blue iridescence. The dual colour arises from a modulation imposed on the multilayer, producing the blue component as a result of a previously undiscovered retro-reflection process.

  20. The AMBEGUJAS phenomenon and colour constancy.

    PubMed

    Bergstrm, Sten Sture

    2004-01-01

    The AMBEGUJAS phenomenon is a reversible flat figure that is spontaneously shifting between two apparent 3-D shapes-'tile' and 'roof'. 2-D perceptions have very rarely been reported. Tied to the shifts between the tile and roof shapes are remarkable changes of perceived colour. In our example, the tile appears to have orange (top half) and blue-green (bottom half) surface colours in white light. The roof appears grey but in an orange illumination and with a blue-green shadow. This phenomenon appears whether a grey display is presented in two coloured illuminations, or a chromatic display with two surface colours (orange and blue-green) is presented in white light. In the coloured illuminations the tile is an example of non-constancy, since its colours are non-veridical colour perceptions. The centre stripe of the display appears to have the same orange and blue-green colours as the lateral stripes but in a shadow. This seems like a colour constancy in a non-constancy situation. An alternative to the classical definition of colour constancy is discussed. PMID:15460510

  1. The original colours of fossil beetles

    PubMed Central

    McNamara, Maria E.; Briggs, Derek E. G.; Orr, Patrick J.; Noh, Heeso; Cao, Hui

    2012-01-01

    Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group. PMID:21957131

  2. How bees discriminate a pattern of two colours from its mirror image.

    PubMed

    Horridge, Adrian

    2015-01-01

    A century ago, in his study of colour vision in the honeybee (Apis mellifera), Karl von Frisch showed that bees distinguish between a disc that is half yellow, half blue, and a mirror image of the same. Although his inference of colour vision in this example has been accepted, some discrepancies have prompted a new investigation of the detection of polarity in coloured patterns. In new experiments, bees restricted to their blue and green receptors by exclusion of ultraviolet could learn patterns of this type if they displayed a difference in green contrast between the two colours. Patterns with no green contrast required an additional vertical black line as a landmark. Tests of the trained bees revealed that they had learned two inputs; a measure and the retinotopic position of blue with large field tonic detectors, and the measure and position of a vertical edge or line with small-field phasic green detectors. The angle between these two was measured. This simple combination was detected wherever it occurred in many patterns, fitting the definition of an algorithm, which is defined as a method of processing data. As long as they excited blue receptors, colours could be any colour to human eyes, even white. The blue area cue could be separated from the green receptor modulation by as much as 50°. When some blue content was not available, the bees learned two measures of the modulation of the green receptors at widely separated vertical edges, and the angle between them. There was no evidence that the bees reconstructed the lay-out of the pattern or detected a tonic input to the green receptors. PMID:25617892

  3. How Bees Discriminate a Pattern of Two Colours from Its Mirror Image

    PubMed Central

    Horridge, Adrian

    2015-01-01

    A century ago, in his study of colour vision in the honeybee (Apis mellifera), Karl von Frisch showed that bees distinguish between a disc that is half yellow, half blue, and a mirror image of the same. Although his inference of colour vision in this example has been accepted, some discrepancies have prompted a new investigation of the detection of polarity in coloured patterns. In new experiments, bees restricted to their blue and green receptors by exclusion of ultraviolet could learn patterns of this type if they displayed a difference in green contrast between the two colours. Patterns with no green contrast required an additional vertical black line as a landmark. Tests of the trained bees revealed that they had learned two inputs; a measure and the retinotopic position of blue with large field tonic detectors, and the measure and position of a vertical edge or line with small-field phasic green detectors. The angle between these two was measured. This simple combination was detected wherever it occurred in many patterns, fitting the definition of an algorithm, which is defined as a method of processing data. As long as they excited blue receptors, colours could be any colour to human eyes, even white. The blue area cue could be separated from the green receptor modulation by as much as 50. When some blue content was not available, the bees learned two measures of the modulation of the green receptors at widely separated vertical edges, and the angle between them. There was no evidence that the bees reconstructed the lay-out of the pattern or detected a tonic input to the green receptors. PMID:25617892

  4. Fruit over sunbed: carotenoid skin colouration is found more attractive than melanin colouration.

    PubMed

    Lefevre, Carmen E; Perrett, David I

    2015-01-01

    Skin colouration appears to play a pivotal part in facial attractiveness. Skin yellowness contributes to an attractive appearance and is influenced both by dietary carotenoids and by melanin. While both increased carotenoid colouration and increased melanin colouration enhance apparent health in Caucasian faces by increasing skin yellowness, it remains unclear, firstly, whether both pigments contribute to attractiveness judgements, secondly, whether one pigment is clearly preferred over the other, and thirdly, whether these effects depend on the sex of the face. Here, in three studies, we examine these questions using controlled facial stimuli transformed to be either high or low in (a) carotenoid colouration, or (b) melanin colouration. We show, firstly, that both increased carotenoid colouration and increased melanin colouration are found attractive compared to lower levels of these pigments. Secondly, we show that carotenoid colouration is consistently preferred over melanin colouration when levels of colouration are matched. In addition, we find an effect of the sex of stimuli with stronger preferences for carotenoids over melanin in female compared to male faces, irrespective of the sex of the observer. These results are interpreted as reflecting preferences for sex-typical skin colouration: men have darker skin than women and high melanization in male faces may further enhance this masculine trait, thus carotenoid colouration is not less desirable, but melanin colouration is relatively more desirable in males compared to females. Taken together, our findings provide further support for a carotenoid-linked health-signalling system that is highly important in mate choice. PMID:25014019

  5. What colour is the car? Implicit memory for colour information in children.

    PubMed

    Mecklenbräuker, S; Hupbach, A; Wippich, W

    2001-11-01

    Three experiments were conducted to examine age-related differences in colour memory. In Experiment 1, preschool age and elementary school age children were given a conceptual test of implicit colour memory (a colour-choice task). They were presented with the names or achromatic versions of previously studied coloured line drawings and asked to select an appropriate colour. Significant priming could be demonstrated: The children chose the previously seen colours more often than was expected by chance. Equivalent priming was found for both versions (pictorial and verbal) suggesting that colour priming may be conceptually mediated. Moreover, colour priming proved to be age invariant. Experiment 2 replicated and extended this finding by using a wider age group (preschool, elementary school, and young adults) and by giving a perceptual implicit task (picture identification) in addition to a verbal colour-choice task. Colour did not affect priming in the perceptual task. Whereas priming showed no developmental change, age-related improvements were observed on an explicit colour memory task that differed only in the test instructions from the implicit colour-choice task (Experiments 2 and 3). Taken together, the results suggest that implicit colour memory may be mediated by conceptual processes that are age invariant. PMID:11765733

  6. Quantifying Plant Colour and Colour Difference as Perceived by Humans Using Digital Images

    PubMed Central

    Kendal, Dave; Hauser, Cindy E.; Garrard, Georgia E.; Jellinek, Sacha; Giljohann, Katherine M.; Moore, Joslin L.

    2013-01-01

    Human perception of plant leaf and flower colour can influence species management. Colour and colour contrast may influence the detectability of invasive or rare species during surveys. Quantitative, repeatable measures of plant colour are required for comparison across studies and generalisation across species. We present a standard method for measuring plant leaf and flower colour traits using images taken with digital cameras. We demonstrate the method by quantifying the colour of and colour difference between the flowers of eleven grassland species near Falls Creek, Australia, as part of an invasive species detection experiment. The reliability of the method was tested by measuring the leaf colour of five residential garden shrub species in Ballarat, Australia using five different types of digital camera. Flowers and leaves had overlapping but distinct colour distributions. Calculated colour differences corresponded well with qualitative comparisons. Estimates of proportional cover of yellow flowers identified using colour measurements correlated well with estimates obtained by measuring and counting individual flowers. Digital SLR and mirrorless cameras were superior to phone cameras and point-and-shoot cameras for producing reliable measurements, particularly under variable lighting conditions. The analysis of digital images taken with digital cameras is a practicable method for quantifying plant flower and leaf colour in the field or lab. Quantitative, repeatable measurements allow for comparisons between species and generalisations across species and studies. This allows plant colour to be related to human perception and preferences and, ultimately, species management. PMID:23977275

  7. Colour and surface fluorescence development and their relationship with Maillard reaction markers as influenced by structural changes during cornflakes production.

    PubMed

    Farroni, Abel; Buera, Mara Del Pilar

    2012-12-01

    The aim of this work was to study colour and surface fluorescence development in relation to the chemical markers for the Maillard reaction at the cooking, flaking and toasting stages of cornflake production process. Colour was measured by a calibrated computer vision system. Surface fluorescence was measured on compressed samples. Aqueous extracted Maillard reaction markers (hydroxymethylfurfural, carboxymethyl-lysine, absorbance at 420nm and total fluorescence) were measured on protease hydrolyzed samples. Sample microstructure was observed by scanning electron microscopy. During cooking the colour coordinates L(?) and b(?) decreased and a(?) increased. After flaking, the samples appeared lighter, while the pigment concentration, fluorescence and hydroxymethylfurfural did not change. Toasting generated bubbles in the matrix and L(?) apparently increased, although brown pigment concentration increased. Pigment concentration did not correlate with surface colour due to the destruction or generation of interfaces. Surface and microstructure effects can be avoided by milling and compressing the samples. PMID:22953910

  8. The Manchester Colour Wheel: enhancing its utility.

    PubMed

    Carruthers, Helen R; Whorwell, Peter J

    2013-06-01

    The Manchester Colour Wheel was developed to investigate the role of colour in the perception of illness in gastroenterology. During validation it was found that positive, neutral, or negative connotations of the shade of a colour were more important than the colour itself. However, when asked to relate mood to a colour, the response rate was greater in individuals with mood disorders than healthy controls. This study assessed whether response rate could be made more uniform by changing the wording of the question. Mood/colour choice was compared, using two slightly different questions, in 105 and 203 healthy volunteers, resulting in response rates of 39% and 95% respectively, with the latter not associated with increased false positive responses. These results show that adjustment of the wording of a mood-related question may allow equal response rates irrespective of the mood status of participants. PMID:24175451

  9. Colour Consideration for Waiting areas in hospitals

    NASA Astrophysics Data System (ADS)

    Zraati, Parisa

    2012-08-01

    Colour is one the most important factors in the nature that can have some affects on human behaviour. Many years ago, it was proven that using colour in public place can have some affect on the users. Depend of the darkness and lightness; it can be vary from positive to negative. The research will mainly focus on the colour and psychological influences and physical factors. The statement of problem in this research is what is impact of colour usually applied to waiting area? The overall aim of the study is to explore the visual environment of hospitals and to manage the colour psychological effect of the hospital users in the waiting area by creating a comfortable, pleasant and cozy environment for users while spend their time in waiting areas. The analysisconcentrate on satisfaction and their interesting regarding applied colour in two private hospital waiting area in Malaysia.

  10. Molecular tests for coat colours in horses.

    PubMed

    Rieder, Stefan

    2009-12-01

    Colour phenotypes may have played a major role during early domestication events and initial selection among domestic animal species. As coat colours mostly follow a relatively simple mode of Mendelian inheritance, they have been among the first traits to be systematically analysed at the molecular level. As a result of the number of genetic tools developed during the past decade, horse coat colour tests have been designed and are now commercially available for some of the basic phenotypes. These tests enable breeders to verify segregation within particular pedigrees, to select specific colour phenotypes according to market demand or studbook policies and to avoid complex inherited diseases associated with some of the colour patterns. This paper reviews the relevance of the topic, describes all currently available tests for coat colours in horses and addresses also ongoing research in this field. PMID:19912415

  11. The Impact of Visual Impairment on Perceived School Climate

    ERIC Educational Resources Information Center

    Schade, Benjamin; Larwin, Karen H.

    2015-01-01

    The current investigation examines whether visual impairment has an impact on a student's perception of the school climate. Using a large national sample of high school students, perceptions were examined for students with vision impairment relative to students with no visual impairments. Three factors were examined: self-reported level of…

  12. The multiple disguises of spiders: web colour and decorations, body colour and movement

    PubMed Central

    Thry, Marc; Casas, Jrme

    2008-01-01

    Diverse functions have been assigned to the visual appearance of webs, spiders and web decorations, including prey attraction, predator deterrence and camouflage. Here, we review the pertinent literature, focusing on potential camouflage and mimicry. Webs are often difficult to detect in a heterogeneous visual environment. Static and dynamic web distortions are used to escape visual detection by prey, although particular silk may also attract prey. Recent work using physiological models of vision taking into account visual environments rarely supports the hypothesis of spider camouflage by decorations, but most often the prey attraction and predator confusion hypotheses. Similarly, visual modelling shows that spider coloration is effective in attracting prey but not in conveying camouflage. Camouflage through colour change might be used by particular crab spiders to hide from predator or prey on flowers of different coloration. However, results obtained on a non-cryptic crab spider suggest that an alternative function of pigmentation may be to avoid UV photodamage through the transparent cuticle. Numerous species are clearly efficient locomotory mimics of ants, particularly in the eyes of their predators. We close our paper by highlighting gaps in our knowledge. PMID:18990672

  13. The multiple disguises of spiders: web colour and decorations, body colour and movement.

    PubMed

    Thry, Marc; Casas, Jrme

    2009-02-27

    Diverse functions have been assigned to the visual appearance of webs, spiders and web decorations, including prey attraction, predator deterrence and camouflage. Here, we review the pertinent literature, focusing on potential camouflage and mimicry. Webs are often difficult to detect in a heterogeneous visual environment. Static and dynamic web distortions are used to escape visual detection by prey, although particular silk may also attract prey. Recent work using physiological models of vision taking into account visual environments rarely supports the hypothesis of spider camouflage by decorations, but most often the prey attraction and predator confusion hypotheses. Similarly, visual modelling shows that spider coloration is effective in attracting prey but not in conveying camouflage. Camouflage through colour change might be used by particular crab spiders to hide from predator or prey on flowers of different coloration. However, results obtained on a non-cryptic crab spider suggest that an alternative function of pigmentation may be to avoid UV photodamage through the transparent cuticle. Numerous species are clearly efficient locomotory mimics of ants, particularly in the eyes of their predators. We close our paper by highlighting gaps in our knowledge. PMID:18990672

  14. Vision channels, contrast sensitivity, and functional vision

    NASA Astrophysics Data System (ADS)

    Ginsburg, Arthur P.

    2004-06-01

    The neurophysiology and psychophysics of vision provide the basis for vision channels. Vision channels are the foundation of understanding spatial vision. This understanding has led to the development of a general model of visual perception and tests of functional vision. The channel model is shown to predict the Gestalt of many objects and perceptual distortions in a wide variety of spatial patterns misnamed as "visual illusions". Contrast sensitivity has been shown, more than visual acuity, to relate to functional vision and the visual quality of everyday objects viewed at work and play. The channel model and differences in contrast sensitivity help explain why people such as drivers with similar good visual acuity can complain of the quality of vision in one eye and not the other from eye disease and can dete4ct and identify objects at significatnly different distances. The peak of the contrast sensitivity function, about 3 to 6 cpd, is most sensitive to detecting objects at low contrast and is shown to relate to the visibility of a variety of objects in a night driving simulator. Using the contrast sensitivity function from sine-wave grating contrast sensitivity charts, EyeView software creates images that relate to the quality of vision.

  15. Chemicals Industry Vision

    SciTech Connect

    none,

    1996-12-01

    Chemical industry leaders articulated a long-term vision for the industry, its markets, and its technology in the groundbreaking 1996 document Technology Vision 2020 - The U.S. Chemical Industry. (PDF 310 KB).

  16. Cataract Vision Simulator

    MedlinePLUS

    ... Prevention News Ask an Eye M.D. Espaol Cataracts What Are Cataracts? Cataract Symptoms Who Is at ... Lens Replacement and Cataract Surgery Cataract Vision Simulator Cataract Vision Simulator Jun. 11, 2014 How do cataracts ...

  17. Cataract Vision Simulator

    MedlinePLUS

    ... Ophthalmologist Español Eye Health / Eye Health A-Z Cataracts Sections What Are Cataracts? Cataract Symptoms Who Is ... Lens Replacement and Cataract Surgery Cataract Vision Simulator Cataract Vision Simulator Jun. 11, 2014 How do cataracts ...

  18. Acute Vision Loss.

    PubMed

    Bagheri, Nika; Mehta, Sonia

    2015-09-01

    Acute vision loss can be transient (lasting <24hours) or persistent (lasting>24hours). When patients present with acute vision loss, it is important to ascertain the duration of vision loss and whether it is a unilateral process affecting one eye or a bilateral process affecting both eyes. This article focuses on causes of acute vision loss in the nontraumatic setting and provides management pearls to help health care providers better triage these patients. PMID:26319342

  19. Ultraviolet vision and foraging in dip and plunge diving birds

    PubMed Central

    Hstad, Olle; Ernstdotter, Emma; deen, Anders

    2005-01-01

    Many fishes are sensitive to ultraviolet (UV) light and display UV markings during courtship. As UV scatters more than longer wavelengths of light, these signals are only effective at short distances, reducing the risk of detection by swimming predators. Such underwater scattering will be insignificant for dip and plunge diving birds, which prey on fishes just below the water surface. One could therefore expect to find adaptations in the eyes of dip and plunge diving birds that tune colour reception to UV signals. We used a molecular method to survey the colour vision tuning of five families of dip or plunge divers and compared the results with those from sister taxa of other foraging methods. We found evidence of extended UV vision only in gulls (Laridae). Based on available evidence, it is more probable that this trait is associated with their terrestrial foraging habits rather than piscivory. PMID:17148194

  20. Ultraviolet vision and foraging in dip and plunge diving birds.

    PubMed

    Hstad, Olle; Ernstdotter, Emma; Odeen, Anders

    2005-09-22

    Many fishes are sensitive to ultraviolet (UV) light and display UV markings during courtship. As UV scatters more than longer wavelengths of light, these signals are only effective at short distances, reducing the risk of detection by swimming predators. Such underwater scattering will be insignificant for dip and plunge diving birds, which prey on fishes just below the water surface. One could therefore expect to find adaptations in the eyes of dip and plunge diving birds that tune colour reception to UV signals. We used a molecular method to survey the colour vision tuning of five families of dip or plunge divers and compared the results with those from sister taxa of other foraging methods. We found evidence of extended UV vision only in gulls (Laridae). Based on available evidence, it is more probable that this trait is associated with their terrestrial foraging habits rather than piscivory. PMID:17148194

  1. Robot Vision Library

    NASA Technical Reports Server (NTRS)

    Howard, Andrew B.; Ansar, Adnan I.; Litwin, Todd E.; Goldberg, Steven B.

    2009-01-01

    The JPL Robot Vision Library (JPLV) provides real-time robot vision algorithms for developers who are not vision specialists. The package includes algorithms for stereo ranging, visual odometry and unsurveyed camera calibration, and has unique support for very wideangle lenses

  2. Local adaptation and divergence in colour signal conspicuousness between monomorphic and polymorphic lineages in a lizard.

    PubMed

    McLean, C A; Moussalli, A; Stuart-Fox, D

    2014-12-01

    Population differences in visual environment can lead to divergence in multiple components of animal coloration including signalling traits and colour patterns important for camouflage. Divergence may reflect selection imposed by different receivers (conspecifics, predators), which depends in turn on the location of the colour patch. We tested for local adaptation of two genetically and phenotypically divergent lineages of a rock-inhabiting lizard, Ctenophorus decresii, by comparing the visual contrast of colour patches to different receivers in native and non-native environments. The lineages differ most notably in male throat coloration, which is polymorphic in the northern lineage and monomorphic in the southern lineage, but also differ in dorsal and lateral coloration, which is visible to both conspecifics and potential predators. Using models of animal colour vision, we assessed whether lineage-specific throat, dorsal and lateral coloration enhanced conspicuousness to conspecifics, increased crypsis to birds or both, respectively, when viewed against the predominant backgrounds from each lineage. Throat colours were no more conspicuous against native than non-native rock but contrasted more strongly with native lichen, which occurs patchily on rocks inhabited by C. decresii. Conversely, neck coloration (lateral) more closely matched native lichen. Furthermore, although dorsal coloration of southern males was consistently more conspicuous to birds than that of northern males, both lineages had similar absolute conspicuousness against their native backgrounds. Combined, our results are consistent with local adaptation of multiple colour traits in relation to multiple receivers, suggesting that geographic variation in background colour has influenced the evolution of lineage-specific coloration in C. decresii. PMID:25330209

  3. Microwave vision for robots

    NASA Technical Reports Server (NTRS)

    Lewandowski, Leon; Struckman, Keith

    1994-01-01

    Microwave Vision (MV), a concept originally developed in 1985, could play a significant role in the solution to robotic vision problems. Originally our Microwave Vision concept was based on a pattern matching approach employing computer based stored replica correlation processing. Artificial Neural Network (ANN) processor technology offers an attractive alternative to the correlation processing approach, namely the ability to learn and to adapt to changing environments. This paper describes the Microwave Vision concept, some initial ANN-MV experiments, and the design of an ANN-MV system that has led to a second patent disclosure in the robotic vision field.

  4. Computational approaches to vision

    NASA Technical Reports Server (NTRS)

    Barrow, H. G.; Tenenbaum, J. M.

    1986-01-01

    Vision is examined in terms of a computational process, and the competence, structure, and control of computer vision systems are analyzed. Theoretical and experimental data on the formation of a computer vision system are discussed. Consideration is given to early vision, the recovery of intrinsic surface characteristics, higher levels of interpretation, and system integration and control. A computational visual processing model is proposed and its architecture and operation are described. Examples of state-of-the-art vision systems, which include some of the levels of representation and processing mechanisms, are presented.

  5. Colour mathematics: with graphs and numbers

    NASA Astrophysics Data System (ADS)

    Lo Presto, Michael C.

    2009-07-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just attempting to memorize them.

  6. Colour Mathematics: With Graphs and Numbers

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2009-01-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just

  7. Representing Object Colour in Language Comprehension

    ERIC Educational Resources Information Center

    Connell, Louise

    2007-01-01

    Embodied theories of cognition hold that mentally representing something "red" engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task

  8. Brilliant Colours from a White Snow Cover

    ERIC Educational Resources Information Center

    Vollmer, Michael; Shaw, Joseph A

    2013-01-01

    Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not

  9. Brilliant Colours from a White Snow Cover

    ERIC Educational Resources Information Center

    Vollmer, Michael; Shaw, Joseph A

    2013-01-01

    Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not…

  10. Representing Object Colour in Language Comprehension

    ERIC Educational Resources Information Center

    Connell, Louise

    2007-01-01

    Embodied theories of cognition hold that mentally representing something "red" engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task…

  11. Acquired color vision deficiency.

    PubMed

    Simunovic, Matthew P

    2016-01-01

    Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations. PMID:26656928

  12. Colour in insect thermoregulation: empirical and theoretical tests in the colour-changing grasshopper, Kosciuscola tristis.

    PubMed

    Umbers, K D L; Herberstein, M E; Madin, J S

    2013-01-01

    Body colours can result in different internal body temperatures, but evidence for the biological significance of colour-induced temperature differences is inconsistent. We investigated the relationship between body colour and temperature in a model insect species that rapidly changes colour. We used an empirical approach and constructed a heat budget model to quantify whether a colour change from black to turquoise has a role in thermoregulation for the chameleon grasshopper (Kosciuscola tristis). Our study shows that colour change in K. tristis provides relatively small temperature differences that vary greatly with wind speed (0.55 C at ms(-1) to 0.05 C at 10 ms(-1)). The biological significance of this difference is unclear and we discuss the requirement for more studies that directly test hypotheses regarding the fitness effects of colour in manipulating body temperature. PMID:23108152

  13. Measurement and prediction of pork colour.

    PubMed

    Van Oeckel, M J; Warnants, N; Boucqué, C V

    1999-08-01

    The extent to which instrumental colour determinations by FOPu (light scattering), Göfo (reflectance) and Labscan II (CIE L*, CIE a* and CIE b*, hue and chroma) are related to the Japanese colour grades was studied. Additionally, four on-line methods: pH1, FOP1, PQM1 (conductivity) and DDLT (Double Density Light Transmission, analogous to Capteur Gras/Maigre), were evaluated for their ability to predict subjectively and objectively colour. One hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were analysed. Of the instrumental colour determinations, CIE L* (r=-0.82), FOPu (r=-0.70) and Göfo (r=0.70) were best correlated with the Japanese colour scores. The Japanese colour grades could be predicted by the on-line instruments, pH1, FOP1, PQM1 and DDLT, with determination coefficients between 15 and 28%. Ultimate meat colour, determined by Japanese colour standards, FOPu, Göfo and CIE L*, was better predicted by DDLT than by the classic on-line instruments: FOP1, pH1 and PQM1, although the standard error of the estimate was similar for all instruments. This means that DDLT, although originally designed for estimating lean meat percentage, can additionally give information about meat quality, in particular colour. However, it must be stressed that the colour estimate by DDLT refers to a population of animals, rather than to individual pigs, because of the number of erroneously assigned samples. PMID:22062695

  14. Improving Access to Vision Care for People Who are Homeless through Eyeglasses Recycling.

    PubMed

    Lam, Janna; Robertson, Kirstin; Robertson, Wesley; Bernstein, Rebecca

    2015-11-01

    Visual impairment disproportionately affects the health and function of people who are homeless. A common and correctable cause of visual impairment is refractive error. However, eyeglasses remain an unmet need for the poor and underinsured. This report describes eyeglasses recycling and vision screening to reduce the burden of correctable visual impairment. PMID:26548683

  15. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... blindness. 1308.13 Section 1308.13 Public Welfare Regulations Relating to Public Welfare (Continued) OFFICE... impairment including blindness. (a) A child is classified as visually impaired when visual impairment, with.... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in...

  16. Artificial selection for food colour preferences.

    PubMed

    Cole, Gemma L; Endler, John A

    2015-04-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection. PMID:25740894

  17. Physicochemical and physiological basis of dichromatic colour

    NASA Astrophysics Data System (ADS)

    Kreft, Samo; Kreft, Marko

    2007-11-01

    Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here, we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing. The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum.

  18. Ophthalmological, cognitive, electrophysiological and MRI assessment of visual processing in preterm children without major neuromotor impairment.

    PubMed

    O'Reilly, Michelle; Vollmer, Brigitte; Vargha-Khadem, Faraneh; Neville, Brian; Connelly, Alan; Wyatt, John; Timms, Chris; de Haan, Michelle

    2010-09-01

    Many studies report chronic deficits in visual processing in children born preterm. We investigated whether functional abnormalities in visual processing exist in children born preterm but without major neuromotor impairment (i.e. cerebral palsy). Twelve such children (< 33 weeks gestation or birthweight < 1000 g) without major neuromotor impairment and 12 born full-term controls were assessed at 8-12 years of age by means of ophthalmological assessment (visual acuity, colour vision, stereopsis, stereoacuity, visual fields, ocular motility, motor fusion), cognitive tests of visual-motor, visual-perceptual and visual-spatial skills and pattern-reversal visual evoked potentials (PR-VEPs). All participants also underwent magnetic resonance imaging (MRI) of the brain and neuromotor assessments. No significant differences were found between the groups on the ophthalmological, visual cognitive, neurological, neuromotor or MRI measures. The P100 component of the PR-VEP showed a significantly shorter latency in the preterm compared with the full-term participants. Whilst this P100 finding suggests that subtle abnormalities may exist at the neurophysiological level, we conclude that visual dysfunction is not systematically associated with preterm birth in the context of normal neurological status. PMID:20712735

  19. Colouration and colour changes of the fiddler crab, Uca capricornis: a descriptive study.

    PubMed

    Detto, Tanya; Hemmi, Jan M; Backwell, Patricia R Y

    2008-01-01

    Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition. PMID:18286186

  20. Colouration and Colour Changes of the Fiddler Crab, Uca capricornis: A Descriptive Study

    PubMed Central

    Detto, Tanya; Hemmi, Jan M.; Backwell, Patricia R. Y.

    2008-01-01

    Colour changes in animals may be triggered by a variety of social and environmental factors and may occur over a matter of seconds or months. Crustaceans, like fiddler crabs (genus Uca), are particularly adept at changing their colour and have been the focus of numerous studies. However, few of these studies have attempted to quantitatively describe the individual variation in colour and pattern or their adaptive significance. This paper quantitatively describes the colour patterns of the fiddler crab Uca capricornis and their ability to change on a socially significant timescale. The most dramatic changes in colour pattern are associated with moulting. These ontogenetic changes result in a general reduction of the colour pattern with increasing size, although females are more colourful and variable than similarly-sized males. Uca capricornis are also capable of rapid colour changes in response to stress, but show no endogenous rhythms associated with the semilunar and tidal cycles commonly reported in other fiddler crabs. The extreme colour polymorphism and the relative stability of the colour patterns in Uca capricornis are consistent with their use in visually mediated mate recognition. PMID:18286186

  1. Using students' misconceptions of primary coloured lights to design a hands-on coloured light mixer

    NASA Astrophysics Data System (ADS)

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak

    2009-06-01

    A surface mount typed multi-coloured Light-Emitting Diode (LED) is used as a light source for the hands-on coloured light mixer. The LED consists of red, green and blue tiny sources but the mixer is designed to have four switches corresponding to red, green, blue and yellow light. These colours correspond to students' misconceptions of primary coloured lights; they realize that the primary colours and the rules for lights mixing are the same as those of paints. To generate a yellow light, a microcontroller placed between four input switches and the LED operates both a red and green tiny sources. In addition, the microcontroller is employed to eliminate some combinations of coloured light mixing to simplify the experiment (basic mode) for non advanced students. If the mixer is used with more advanced students, a number of combinations will increase and students need more analytical skills to find out the primary coloured lights (the coloured lights that can not be produced by the mixing of any other coloured lights). Therefore, the mixer is able to use with more advanced and non advanced students depending on the program in the microcontroller and some modifications of the circuit. Furthermore, to introduce students an idea that other hues or shades can be generated by mixing of these three primary coloured lights of different intensities, a tuning circuit is integrated to vary an intensity of the green light source.

  2. Individual colour patches as multicomponent signals.

    PubMed

    Grether, Gregory F; Kolluru, Gita R; Nersissian, Karen

    2004-08-01

    Colour patches are complex traits, the components of which may evolve independently through a variety of mechanisms. Although usually treated as simple, two-dimensional characters and classified as either structural or pigmentary, in reality colour patches are complicated, three-dimensional structures that often contain multiple pigment types and structural features. The basic dermal chromatophore unit of fishes, reptiles and amphibians consists of three contiguous cell layers. Xanthophores and erythrophores in the outermost layer contain carotenoid and pteridine pigments that absorb short-wave light; iridophores in the middle layer contain crystalline platelets that reflect light back through the xanthophores; and melanophores in the basal layer contain melanins that absorb light across the spectrum. Changes in any one component of a chromatophore unit can drastically alter the reflectance spectrum produced, and for any given adaptive outcome (e.g. an increase in visibility), there may be multiple biochemical or cellular routes that evolution could take, allowing for divergent responses by different populations or species to similar selection regimes. All of the mechanisms of signal evolution that previously have been applied to single ornaments (including whole colour patches) could potentially be applied to the individual components of colour patches. To reach a complete understanding of colour patch evolution, however, it may be necessary to take an explicitly multi-trait approach. Here, we review multiple trait evolution theory and the basic mechanisms of colour production in fishes, reptiles and amphibians, and use a combination of computer simulations and empirical examples to show how multiple trait evolution theory can be applied to the components of single colour patches. This integrative perspective on animal colouration opens up a host of new questions and hypotheses. We offer specific, testable functional hypotheses for the most common pigmentary (carotenoid, pteridine and melanin) and structural components of vertebrate colour patches. PMID:15366764

  3. FPGA Vision Data Architecture

    NASA Technical Reports Server (NTRS)

    Morfopoulos, Arin C.; Pham, Thang D.

    2013-01-01

    JPL has produced a series of FPGA (field programmable gate array) vision algorithms that were written with custom interfaces to get data in and out of each vision module. Each module has unique requirements on the data interface, and further vision modules are continually being developed, each with their own custom interfaces. Each memory module had also been designed for direct access to memory or to another memory module.

  4. The colour wheels of art, perception, science and physiology

    NASA Astrophysics Data System (ADS)

    Harkness, Nick

    2006-06-01

    Colour is not the domain of any one discipline be it art, philosophy, psychology or science. Each discipline has its own colour wheel and this presentation examines the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology (after image) with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell. The paper analyses and discusses the differences between the four colour wheels using the Natural Colour System notation as the reference for hue (the position of colours within each of the colour wheels). Examination of the colour wheels shows the dominance of blue in the wheels of art, science and physiology particularly at the expense of green. This paper does not consider the three-dimensionality of colour space its goal was to review the hue of a colour with regard to its position on the respective colour wheels.

  5. The Social Lives of Canadian Youths with Visual Impairments

    ERIC Educational Resources Information Center

    Gold, Deborah; Shaw, Alexander; Wolffe, Karen

    2010-01-01

    This survey of the social and leisure experiences of Canadian youths with visual impairments found that, in general, youths with low vision experienced more social challenges than did their peers who were blind. Levels of social support were not found to differ on the basis of level of vision, sex, or age. (Contains 1 figure and 1 table.)

  6. Artificial human vision camera

    NASA Astrophysics Data System (ADS)

    Goudou, J.-F.; Maggio, S.; Fagno, M.

    2014-10-01

    In this paper we present a real-time vision system modeling the human vision system. Our purpose is to inspire from human vision bio-mechanics to improve robotic capabilities for tasks such as objects detection and tracking. This work describes first the bio-mechanical discrepancies between human vision and classic cameras and the retinal processing stage that takes place in the eye, before the optic nerve. The second part describes our implementation of these principles on a 3-camera optical, mechanical and software model of the human eyes and associated bio-inspired attention model.

  7. Biomimetic machine vision system.

    PubMed

    Harman, William M; Barrett, Steven F; Wright, Cameron H G; Wilcox, Michael

    2005-01-01

    Real-time application of digital imaging for use in machine vision systems has proven to be prohibitive when used within control systems that employ low-power single processors without compromising the scope of vision or resolution of captured images. Development of a real-time machine analog vision system is the focus of research taking place at the University of Wyoming. This new vision system is based upon the biological vision system of the common house fly. Development of a single sensor is accomplished, representing a single facet of the fly's eye. This new sensor is then incorporated into an array of sensors capable of detecting objects and tracking motion in 2-D space. This system "preprocesses" incoming image data resulting in minimal data processing to determine the location of a target object. Due to the nature of the sensors in the array, hyperacuity is achieved thereby eliminating resolutions issues found in digital vision systems. In this paper, we will discuss the biological traits of the fly eye and the specific traits that led to the development of this machine vision system. We will also discuss the process of developing an analog based sensor that mimics the characteristics of interest in the biological vision system. This paper will conclude with a discussion of how an array of these sensors can be applied toward solving real-world machine vision issues. PMID:15850101

  8. Analysis of fusion gene and encoded photopigment of colour-blind humans.

    PubMed

    Neitz, J; Neitz, M; Jacobs, G H

    1989-12-01

    In humans, long-wavelength-sensitive and middle-wavelength-sensitive cone pigments are encoded by genes lying in a head-to-tail tandem array on the X chromosome. Deficiencies in red-green colour vision seem to arise from unequal recombination of these normal X-linked genes. In some dichromats this recombination is believed to yield a fusion gene encoding a product with an absorption spectrum similar to that of one or the other of the normal photopigments. Until now, however, such a relationship between the structure of a pigment gene and the spectral properties of its encoded pigment has not been directly shown. We have now sequenced a fusion gene isolated from a red-green colour-blind human and determined the spectral properties of the pigment that it encodes. The absorption spectrum of the photopigment was very similar to that of normal middle-wavelength-sensitive photopigment, even though about half of its DNA coding sequence seems to be derived from a gene encoding normal long-wavelength-sensitive pigment. These results indicate the regions of the X-encoded photopigment apoproteins that are responsible for differences in their spectral tuning, and imply that the striking variations in colour vision among anomalous trichromats of a particular type are not attributable to anomalous pigments with differing spectral peaks. PMID:2574415

  9. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  10. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  11. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  12. 45 CFR 1308.13 - Eligibility criteria: Visual impairment including blindness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... A child is visually impaired if: (1) The vision loss meets the definition of legal blindness in the... vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees. (b..., limited field of vision, cataracts, etc....

  13. Coherent modulation of stimulus colour can affect visually induced self-motion perception.

    PubMed

    Nakamura, Shinji; Seno, Takeharu; Ito, Hiroyuki; Sunaga, Shoji

    2010-01-01

    The effects of dynamic colour modulation on vection were investigated to examine whether perceived variation of illumination affects self-motion perception. Participants observed expanding optic flow which simulated their forward self-motion. Onset latency, accumulated duration, and estimated magnitude of the self-motion were measured as indices of vection strength. Colour of the dots in the visual stimulus was modulated between white and red (experiment 1), white and grey (experiment 2), and grey and red (experiment 3). The results indicated that coherent colour oscillation in the visual stimulus significantly suppressed the strength of vection, whereas incoherent or static colour modulation did not affect vection. There was no effect of the types of the colour modulation; both achromatic and chromatic modulations turned out to be effective in inhibiting self-motion perception. Moreover, in a situation where the simulated direction of a spotlight was manipulated dynamically, vection strength was also suppressed (experiment 4). These results suggest that observer's perception of illumination is critical for self-motion perception, and rapid variation of perceived illumination would impair the reliabilities of visual information in determining self-motion. PMID:21425698

  14. A roadmap for interpreting the literature on vision and driving.

    PubMed

    Owsley, Cynthia; Wood, Joanne M; McGwin, Gerald

    2015-01-01

    Over the past several decades there has been a sharp increase in the number of studies focused on the relationship between vision and driving. The intensified attention to this topic has most likely been stimulated by the lack of an evidence basis for determining vision standards for driving licensure and a poor understanding about how vision impairment impacts driver safety and performance. Clinicians depend on the literature on vision and driving to advise visually impaired patients appropriately about driving fitness. Policy makers also depend on the scientific literature in order to develop guidelines that are evidence-based and are thus fair to persons who are visually impaired. Thus it is important for clinicians and policy makers alike to understand how various study designs and measurement methods should be interpreted so that the conclusions and recommendations they make are not overly broad, too narrowly constrained, or even misguided. We offer a methodological framework to guide interpretations of studies on vision and driving that can also serve as a heuristic for researchers in the area. Here, we discuss research designs and general measurement methods for the study of vision as they relate to driver safety, driver performance, and driver-centered (self-reported) outcomes. PMID:25753389

  15. Why colour in subterranean vertebrates? Exploring the evolution of colour patterns in caecilian amphibians.

    PubMed

    Wollenberg, K C; Measey, C John

    2009-05-01

    The proximate functions of animal skin colour are difficult to assign as they can result from natural selection, sexual selection or neutral evolution under genetic drift. Most often colour patterns are thought to signal visual stimuli; so,their presence in subterranean taxa is perplexing. We evaluate the adaptive nature of colour patterns in nearly a third of all known species of caecilians, an order of amphibians most of which live in tropical soils and leaf litter. We found that certain colour pattern elements in caecilians can be explained based on characteristics concerning above-ground movement. Our study implies that certain caecilian colour patterns have convergently evolved under selection and we hypothesize their function most likely to be a synergy of aposematism and crypsis, related to periods when individuals move overground. In a wider context, our results suggest that very little exposure to daylight is required to evolve and maintain a varied array of colour patterns in animal skin. PMID:21462404

  16. Low vision goggles: optical design studies

    NASA Astrophysics Data System (ADS)

    Levy, Ofer; Apter, Boris; Efron, Uzi

    2006-08-01

    Low Vision (LV) due to Age Related Macular Degeneration (AMD), Glaucoma or Retinitis Pigmentosa (RP) is a growing problem, which will affect more than 15 million people in the U.S alone in 2010. Low Vision Aid Goggles (LVG) have been under development at Ben-Gurion University and the Holon Institute of Technology. The device is based on a unique Image Transceiver Device (ITD), combining both functions of imaging and Display in a single chip. Using the ITD-based goggles, specifically designed for the visually impaired, our aim is to develop a head-mounted device that will allow the capture of the ambient scenery, perform the necessary image enhancement and processing, and re-direct it to the healthy part of the patient's retina. This design methodology will allow the Goggles to be mobile, multi-task and environmental-adaptive. In this paper we present the optical design considerations of the Goggles, including a preliminary performance analysis. Common vision deficiencies of LV patients are usually divided into two main categories: peripheral vision loss (PVL) and central vision loss (CVL), each requiring different Goggles design. A set of design principles had been defined for each category. Four main optical designs are presented and compared according to the design principles. Each of the designs is presented in two main optical configurations: See-through system and Video imaging system. The use of a full-color ITD-Based Goggles is also discussed.

  17. Vision and vision-related outcome measures in multiple sclerosis

    PubMed Central

    Balcer, Laura J.; Miller, David H.; Reingold, Stephen C.

    2015-01-01

    Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis. PMID:25433914

  18. Composition of a Vision Screen for Servicemembers With Traumatic Brain Injury: Consensus Using a Modified Nominal Group Technique

    PubMed Central

    Finkelstein, Marsha; Llanos, Imelda; Scheiman, Mitchell; Wagener, Sharon Gowdy

    2014-01-01

    Vision impairment is common in the first year after traumatic brain injury (TBI), including among service members whose brain injuries occurred during deployment in Iraq and Afghanistan. Occupational therapy practitioners provide routine vision screening to inform treatment planning and referral to vision specialists, but existing methods are lacking because many tests were developed for children and do not screen for vision dysfunction typical of TBI. An expert panel was charged with specifying the composition of a vision screening protocol for servicemembers with TBI. A modified nominal group technique fostered discussion and objective determinations of consensus. After considering 29 vision tests, the panel recommended a nine-test vision screening that examines functional performance, self-reported problems, farnear acuity, reading, accommodation, convergence, eye alignment and binocular vision, saccades, pursuits, and visual fields. Research is needed to develop reliable, valid, and clinically feasible vision screening protocols to identify TBI-related vision disorders in adults. PMID:25005505

  19. Blending of animal colour patterns by hybridization

    PubMed Central

    Miyazawa, Seita; Okamoto, Michitoshi; Kondo, Shigeru

    2010-01-01

    Biologists have long been fascinated by the amazing diversity of animal colour patterns. Despite much interest, the underlying evolutionary and developmental mechanisms contributing to their rich variety remain largely unknown, especially the vivid and complex colour patterns seen in vertebrates. Here, we show that complex and camouflaged animal markings can be formed by the 'blending' of simple colour patterns. A mathematical model predicts that crossing between animals having inverted spot patterns (for example, 'light spots on a dark background' and 'dark spots on a light background') will necessarily result in hybrid offspring that have camouflaged labyrinthine patterns as 'blended' intermediate phenotypes. We confirmed the broad applicability of the model prediction by empirical examination of natural and artificial hybrids of salmonid fish. Our results suggest an unexplored evolutionary process by means of 'pattern blending', as one of the possible mechanisms underlying colour pattern diversity and hybrid speciation. PMID:20842190

  20. Colour television image analysis of carious lesions.

    PubMed

    Rodda, J C; Mortimer, K V; Williams, E D

    1975-07-25

    The new technique of colour television image analysis has been used to produce seven-colour contour maps of the radiodensity of micro-radiographs of enamel caries. This method permits the detailed measurement of the mineral content of enamel carious lesions to a sensitivity of +/-3% of the level of complete mineralisation. By selection of appropriate aluminium step-wedges, exposed simultaneously with the tooth section, the whole range of mineral content can be assessed. PMID:1148897

  1. Colour preferences of juvenile turbot (Scophthalmus maximus).

    PubMed

    Li, Xian; Chi, Liang; Tian, Huiqin; Meng, Lingjie; Zheng, Jimeng; Gao, Xiaolong; Liu, Ying

    2016-03-15

    The background colour of aquaculture tanks is normally chosen based on practical experience and/or observations of fish behaviour and the growth rates achieved. However, some farmed species, including turbot, are sentient and can show a preference for a particular environment. In the current study, a self-referent colour preference device was developed and the self-referent colour preference of farmed fish investigated. In experiment 1, the background colour preference of juvenile turbot cultured under a grey background for >3months post-incubation was evaluated. Based on these results, in experiment 2, juvenile turbot were adapted to blue, pink, white, or black backgrounds for 50days and their preferences established. Meanwhile, the growth rates, feed intake, and metabolic rates (including oxygen consumption rate, and ammonia excretion rate) of the turbot were evaluated. The results showed that turbot farmed under a grey background, or after long-term white, blue, pink and black colour adaptation, always displayed a preference for a white background and a dislike for black, red, or brown backgrounds, although their body colour was greyish. Long-term adaptation influenced the frequency of juveniles selecting white, black, pink or blue backgrounds. They showed the highest growth rate, feed intake, and metabolic rates under blue and white backgrounds, and the lowest under a black background in accordance with their preferences shown in experiment 1. Although it is unclear how turbot determine their self-referent colour preferences over such a short period of time, these results indicate that dark colours are unsuitable for the aquaculture of turbot culture in terms of the welfare of the fish. PMID:26792527

  2. Plants and colour: Flowers and pollination

    NASA Astrophysics Data System (ADS)

    Miller, Renee; Owens, Simon J.; Rrslett, Bjrn

    2011-03-01

    While there is a range of colours found in plants the predominant colour is green. Pigments in plants have several roles e.g. photosynthesis and signalling. If colour is to be used as a signal then it must stand out from green. However, one should be aware that there are also coloured compounds where we have not yet fully investigated the role of colour in their functionsthey may have roles in, for example, defence or heat exchange. In this paper, we will describe the basic chemistry of the major pigments found in plants and especially floral pigments. We will then discuss their locations in parts of the flower (such as sepals, petals, pollen and nectar), the cells in which they are found and their sub-cellular locations. Floral pigments have a large role to play in pollination of flowers by animals. They can and are modified in many ways during the development of flowers in nature, for example, at emergence and post-pollination. There are a range of biochemical mechanisms of colour change both within flowers and in isolated pigments. Some of the factors influencing colour are temperature, co-pigments, pH, metals, sugars, anthocyanin stacking and cell shape. There is a renewed interest in analysing floral pigments and how they are modified partly because of advances in recombinant DNA technologies, but also because of pollinators and their significance to biodiversity and for evolutionary studies. There is continued strong interest from the horticultural industry for the introduction of new colours e.g. the blue rose and for the exploitation of natural dyes. Funding in this area may impact future research in a potentially beneficial way but it must not deflect us from science-based conservation.

  3. THE COLOUR GLASS CONDENSATE: AN INTRODUCTION

    SciTech Connect

    IANCU,E.; LEONIDOV,A.; MCLERRAN,L.

    2001-08-06

    In these lectures, the authors develop the theory of the Colour Glass Condensate. This is the matter made of gluons in the high density environment characteristic of deep inelastic scattering or hadron-hadron collisions at very high energy. The lectures are self contained and comprehensive. They start with a phenomenological introduction, develop the theory of classical gluon fields appropriate for the Colour Glass, and end with a derivation and discussion of the renormalization group equations which determine this effective theory.

  4. Vision Screening Programs in Children

    PubMed Central

    Damji, Karim F.

    1988-01-01

    Amblyopia, strabismus, and severe refractive errors are important causes of visual impairment in children. The author of this article reviews important considerations for pediatric vision screening and suggests a simple, reliable, and inexpensive approach for the primary-care physician in screening children for potentially serious visual disorders. He emphasizes the cardinal role of the primary-care physician in detecting these disorders early, when optimal treatment can be provided. Assessment of the visual acuity in each eye is the basic principle of this approach. Indications for referral in each age group, from newborns to preschoolers, are outlined. The success of such a program will depend on effective co-ordination of all factors involved: public and physician education, screening, re-screening, subsequent evaluation of diagnosis, and the adoption of an optimal treatment plan. PMID:21253176

  5. Angle-Insensitive Structural Colours based on Metallic Nanocavities and Coloured Pixels beyond the Diffraction Limit

    PubMed Central

    Wu, Yi-Kuei Ryan; Hollowell, Andrew E.; Zhang, Cheng; Guo, L. Jay

    2013-01-01

    To move beyond colorant-based pigmentation display technologies, a variety of photonic and plasmonic crystal based structures have been designed and applied as colour filters. Nanostructure based colour filtering offers increased efficiencies, low power consumption, slim dimensions, and enhanced resolution. However, incident angle tolerance still needs to be improved. In this work, we propose a new scheme through localized resonance in metallic nanoslits by light funneling. Angle insensitive colour filters up to 80 degrees have been achieved, capable of wide colour tunability across the entire visible band with pixel size beyond the diffraction limit (~?/2). This work opens the door to angle insensitive manipulation of light with structural filtering. PMID:23378925

  6. Motion cues improve the performance of harnessed bees in a colour learning task.

    PubMed

    Balamurali, G S; Somanathan, Hema; Hempel de Ibarra, N

    2015-05-01

    The proboscis extension conditioning (PER) is a successful behavioural paradigm for studying sensory and learning mechanisms in bees. Whilst mainly used with olfactory and tactile stimuli, more recently reliable PER conditioning has been achieved with visual stimuli such as colours and looming stripes. However, the results reported in different studies vary quite strongly, and it remains controversially discussed how to best condition visual PER. It is particularly striking that visual PER leads to more limited performance as compared to visual conditioning of free-flying bees. It could be that visual PER learning is affected by the lack of movement and that the presence of visual motion cues could compensate for it. We tested whether bees would show differences in learning performances when conditioned either with a colour and motion stimulus in combination or with colour alone. Colour acquisition was improved in the presence of the motion stimulus. The result is consistent with the idea that visual learning might be tightly linked to movement in bees, given that they use vision predominantly during flight. Our results further confirm recent findings that successful visual PER conditioning in bees is achievable without obligatorily removing the antennae. PMID:25739517

  7. Flower colour adaptation in a mimetic orchid

    PubMed Central

    Newman, Ethan; Anderson, Bruce; Johnson, Steven D.

    2012-01-01

    Although the tremendous variability in floral colour among angiosperms is often attributed to divergent selection by pollinators, it is usually difficult to preclude the possibility that floral colour shifts were driven by non-pollinator processes. Here, we examine the adaptive significance of flower colour in Disa ferruginea, a non-rewarding orchid that is thought to attract its butterfly pollinator by mimicking the flowers of sympatric nectar-producing species. Disa ferruginea has red flowers in the western part of its range and orange flowers in the eastern parta colour shift that we hypothesized to be the outcome of selection for resemblance to different local nectar-producing plants. Using reciprocal translocations of red and orange phenotypes as well as arrays of artificial flowers, we found that the butterfly Aeropetes tulbaghia, the only pollinator of the orchid, preferred both the red phenotype and red artificial flowers in the west where its main nectar plant also has red flowers, and both the orange phenotype and orange artificial flowers in the east, where its main nectar plant has orange flowers. This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator. PMID:22298842

  8. Salience of Primary and Secondary Colours in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Pitchford, Nicola; Hart, Lynsey; Davies, Ian R. L.; Clausse, Samantha; Jennings, Siobhan

    2008-01-01

    Primary colour terms ("black", "white", "red", "green", "yellow", and "blue") are more fundamental in colour language than secondary colour terms ("pink", "purple", "orange", "brown", and "grey"). Here, we assess whether this distinction exists in the absence of language, by investigating whether primary colours attract and sustain preverbal…

  9. Salience of Primary and Secondary Colours in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Pitchford, Nicola; Hart, Lynsey; Davies, Ian R. L.; Clausse, Samantha; Jennings, Siobhan

    2008-01-01

    Primary colour terms ("black", "white", "red", "green", "yellow", and "blue") are more fundamental in colour language than secondary colour terms ("pink", "purple", "orange", "brown", and "grey"). Here, we assess whether this distinction exists in the absence of language, by investigating whether primary colours attract and sustain preverbal

  10. New Term, New Vision?

    ERIC Educational Resources Information Center

    Ravenhall, Mark

    2011-01-01

    During the affluent noughties it was sometimes said of government that it had "more visions than Mystic Meg and more pilots than British Airways". In 2011, the pilots, the pathfinders, the new initiatives are largely gone--implementation is the name of the game--but the visions remain. The latest one, as it affects adult learners, is in the

  11. Overview of computer vision

    SciTech Connect

    Gevarter, W.B.

    1982-09-01

    An overview of computer vision is provided. Image understanding and scene analysis are emphasized, and pertinent aspects of pattern recognition are treated. The basic approach to computer vision systems, the techniques utilized, applications, the current existing systems and state-of-the-art issues and research requirements, who is doing it and who is funding it, and future trends and expectations are reviewed.

  12. Your Child's Vision

    MedlinePLUS

    ... Other Parents Are Reading Signing Kids Up for Sports 15-Minute Meal: Salmon Pregnant? Your Baby's Growth 5 Ways to Prepare for an Allergy Emergency Cerebral Palsy: Caring for Your Child Your Child's Vision KidsHealth > For Parents > Your Child's Vision Print A ...

  13. New Term, New Vision?

    ERIC Educational Resources Information Center

    Ravenhall, Mark

    2011-01-01

    During the affluent noughties it was sometimes said of government that it had "more visions than Mystic Meg and more pilots than British Airways". In 2011, the pilots, the pathfinders, the new initiatives are largely gone--implementation is the name of the game--but the visions remain. The latest one, as it affects adult learners, is in the…

  14. INSIGHT: Vision & Leadership, 2002.

    ERIC Educational Resources Information Center

    McGraw, Tammy, Ed.

    2002-01-01

    This publication focuses on promising new and emerging technologies and what they might mean to the future of K-12 schools. Half of the volume contains articles devoted in some way to "Vision," and articles in the other half are under the heading of "Leadership." Contents in the "Vision" section include: "The Future of Reading and Learning To…

  15. Panoramic stereo sphere vision

    NASA Astrophysics Data System (ADS)

    Feng, Weijia; Zhang, Baofeng; Röning, Juha; Zong, Xiaoning; Yi, Tian

    2013-01-01

    Conventional stereo vision systems have a small field of view (FOV) which limits their usefulness for certain applications. While panorama vision is able to "see" in all directions of the observation space, scene depth information is missed because of the mapping from 3D reference coordinates to 2D panoramic image. In this paper, we present an innovative vision system which builds by a special combined fish-eye lenses module, and is capable of producing 3D coordinate information from the whole global observation space and acquiring no blind area 360°×360° panoramic image simultaneously just using single vision equipment with one time static shooting. It is called Panoramic Stereo Sphere Vision (PSSV). We proposed the geometric model, mathematic model and parameters calibration method in this paper. Specifically, video surveillance, robotic autonomous navigation, virtual reality, driving assistance, multiple maneuvering target tracking, automatic mapping of environments and attitude estimation are some of the applications which will benefit from PSSV.

  16. Macular colour contrast sensitivity in ocular hypertension and glaucoma: evidence for two types of defect.

    PubMed Central

    Falcao-Reis, F. M.; O'Sullivan, F.; Spileers, W.; Hogg, C.; Arden, G. B.

    1991-01-01

    Colour contrast sensitivity (CCS) of a large cohort of glaucomatous patients, ocular hypertensive patients (OH), and normal persons was measured at six-month intervals during a two-year period. The OHs were graded into high, medium, and low risk groups. 69% of glaucomatous patients and 32% of all OHs had CCS thresholds greater than the mean plus 2 SDs of the controls. Satisfactory specificity and sensitivity could not be obtained by adjusting the criterion of threshold. In abnormal eyes, progressive small increases of threshold occurred during the study, but glaucomatous eyes with normal thresholds on the first visit retained normal thresholds in the subsequent visits. Although our system is very sensitive and precise, the proportion of abnormalities detected is no greater than with other techniques. In some glaucomatous patients there is a true preservation of colour vision which does not merely reflect the limitations of the test employed. PMID:1954208

  17. A Handheld LED Coloured-Light Mixer for Students to Learn Collaboratively the Primary Colours of Light

    ERIC Educational Resources Information Center

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

    2009-01-01

    To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny…

  18. A Handheld LED Coloured-Light Mixer for Students to Learn Collaboratively the Primary Colours of Light

    ERIC Educational Resources Information Center

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

    2009-01-01

    To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny

  19. From dichoptic to dichotic: historical contrasts between binocular vision and binaural hearing.

    PubMed

    Wade, Nicholas J; Ono, Hiroshi

    2005-01-01

    Phenomena involving vision with two eyes have been commented upon for several thousand years whereas those concerned with hearing with two ears have a much more recent history. Studies of binocular vision and binaural hearing are contrasted with respect to the singleness of the percept, experimental manipulations of dichoptic and dichotic stimuli, eye and ear dominance, spatial localisation, and the instruments used to stimulate the paired organs. One of the principal phenomena that led to studies of dichotic hearing was dichoptic colour mixing. There was similar disagreement regarding whether colours or sounds could be combined when presented to different paired organs. Direction and distance in visual localisation were analysed before those for auditory localisation, partly due to difficulties in controlling the stimuli. Instruments for investigating binocular vision, like the stereoscope and pseudoscope, were invented before those for binaural hearing, like the stethophone and pseudophone. PMID:16042189

  20. Literature and information in vision care and vision science.

    PubMed

    Goss, David A

    2008-11-01

    The explosion of information in vision care and vision science makes keeping up with the literature and information in the field challenging. This report examines the nature of literature and information in vision care and vision science. A variety of topics are discussed, including the general nature of scientific and clinical journals, journals in vision science and vision care, resources available for searches for literature and information, and issues involved in the evaluation of journals and other information sources. Aspects of the application of citation analysis to vision care and vision science are reviewed, and a new citation analysis of a leading textbook in vision care (Borish's Clinical Refraction) is presented. This report is directed toward anyone who wants to be more informed about the literature of vision care and vision science, whether they are students, clinicians, educators, or librarians. PMID:19811764

  1. A handheld LED coloured-light mixer for students to learn collaboratively the primary colours of light

    NASA Astrophysics Data System (ADS)

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

    2009-03-01

    To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny light-emitting diodes (LEDs) producing primary colours are combined with green intensity varying circuitry to generate the standard colour-triangle secondary colours and various shades ranging from yellow to orange and pale blue to cyan. In the laboratory, students worked collaboratively, predicting, observing and explaining, and finally discussing until there was a consensus.

  2. Spelling Performance of Visually Impaired Adults

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos S.; Arvaniti, Evmorfia K.; Dimitriadi, Despina I.; Gkoutsioudi, Vasiliki G.; Zantali, Christina I.

    2009-01-01

    Visual processes undoubtedly play an important role in print reading as well as in spelling. In the present study we intend to compare the spelling performance of visually impaired individuals (both individuals who are blind and individuals with low vision) with that of their fully sighted peers. An analysis of errors (misspelled words and

  3. Flower colour and cytochromes P450

    PubMed Central

    Tanaka, Yoshikazu; Brugliera, Filippa

    2013-01-01

    Cytochromes P450 play important roles in biosynthesis of flavonoids and their coloured class of compounds, anthocyanins, both of which are major floral pigments. The number of hydroxyl groups on the B-ring of anthocyanidins (the chromophores and precursors of anthocyanins) impact the anthocyanin colour, the more the bluer. The hydroxylation pattern is determined by two cytochromes P450, flavonoid 3?-hydroxylase (F3?H) and flavonoid 3?,5?-hydroxylase (F3?5?H) and thus they play a crucial role in the determination of flower colour. F3?H and F3?5?H mostly belong to CYP75B and CYP75A, respectively, except for the F3?5?Hs in Compositae that were derived from gene duplication of CYP75B and neofunctionalization. Roses and carnations lack blue/violet flower colours owing to the deficiency of F3?5?H and therefore lack the B-ring-trihydroxylated anthocyanins based upon delphinidin. Successful redirection of the anthocyanin biosynthesis pathway to delphinidin was achieved by expressing F3?5?H coding regions resulting in carnations and roses with novel blue hues that have been commercialized. Suppression of F3?5?H and F3?H in delphinidin-producing plants reduced the number of hydroxyl groups on the anthocyanidin B-ring resulting in the production of monohydroxylated anthocyanins based on pelargonidin with a shift in flower colour to orange/red. Pelargonidin biosynthesis is enhanced by additional expression of a dihydroflavonol 4-reductase that can use the monohydroxylated dihydrokaempferol (the pelargonidin precursor). Flavone synthase II (FNSII)-catalysing flavone biosynthesis from flavanones is also a P450 (CYP93B) and contributes to flower colour, because flavones act as co-pigments to anthocyanins and can cause blueing and darkening of colour. However, transgenic plants expression of a FNSII gene yielded paler flowers owing to a reduction of anthocyanins because flavanones are precursors of anthocyanins and flavones. PMID:23297355

  4. Discriminating colors through a red filter by protanopes and colour normals.

    PubMed

    Diaconu, Vasile; Sullivan, David; Bouchard, Jean F; Vucea, Valentina

    2010-01-01

    Individuals with color vision deficiency have difficulties in differentiating colour in their daily activities. Through certain coloured filters, dichromats may report an improvement of their capacity to differentiate colors, but it is not known if this is achieved by means of a chromatic mechanism. The present study attempts to explain the mechanism by which a coloured filter can produce a beneficial effect in dichromatic visual perception and what is the nature of this improvement. Four male protanopes and four normal trichromats (two males and two females) participated in the present study. We evaluated the effect of the red filter (with a spectral transmittance similar to that of the X-Chrom filter) on the detection thresholds for monochromatic light stimuli from 420 to 660 nm in 20 nm steps. The increment spectral sensitivity functions were measured for 1.2 degrees diameter test flashes presented for 300 ms on a 60-cd m(-2) illuminant C background using an optical bench with a monochromator, for both filter and no filter conditions. The capacity to correctly name green, yellow and red for the monochromatic lights of 550, 575 and 625 nm presented for 300 ms on a 60 cd m(-2) illuminant C background screen was also evaluated with and without the red filter. The spectral sensitivity data suggest that, the use of a red filter improves the protanope's capacity to detect long wavelength light stimuli. The results on the colors naming procedure demonstrate that the red filter modifies colour perception in normal and protanope subjects. In normals, only the red color perception is preserved, and typical colour perception for the green and the yellow is lost. Without the filter, all the protanopes demonstrated a residual colour perception for red and green colours. Through the red filter only red colour perception remains. A red filter does not improve the protanopic red-green perception, but it does improve the ability of the protanope to detect long-wavelength light. This improvement seems to arise by means of the luminance mechanism. PMID:20444111

  5. Structural colour and iridescence in plants: the poorly studied relations of pigment colour

    PubMed Central

    Glover, Beverley J.; Whitney, Heather M.

    2010-01-01

    Background Colour is a consequence of the optical properties of an object and the visual system of the animal perceiving it. Colour is produced through chemical and structural means, but structural colour has been relatively poorly studied in plants. Scope This Botanical Briefing describes the mechanisms by which structures can produce colour. In plants, as in animals, the most common mechanisms are multilayers and diffraction gratings. The functions of structural colour are then discussed. In animals, these colours act primarily as signals between members of the same species, although they can also play roles in camouflaging animals from their predators. In plants, multilayers are found predominantly in shade-plant leaves, suggesting a role either in photoprotection or in optimizing capture of photosynthetically active light. Diffraction gratings may be a surprisingly common feature of petals, and recent work has shown that they can be used by bees as cues to identify rewarding flowers. Conclusions Structural colour may be surprisingly frequent in the plant kingdom, playing important roles alongside pigment colour. Much remains to be discovered about its distribution, development and function. PMID:20142263

  6. A Computerized System for Workplace Design for Visually Impaired Workers.

    ERIC Educational Resources Information Center

    Chen, J-G; Hou, C-A

    1991-01-01

    VITAL (Vision Impaired Task and Assignment Lexicon) is an integrated computerized system that performs workplace design tasks for visually impaired workers. VITAL consists of three modules: ergonomics consultation, disability index, and work measurement. Evaluation indicated that VITAL could be used as a tool to help nonprofessional vocational

  7. Identity Development in German Adolescents with and without Visual Impairments

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2013-01-01

    Introduction: The study reported here assessed the exploration of identity and commitment to an identity in German adolescents with and without visual impairments. Methods: In total, 178 adolescents with visual impairments (blindness or low vision) and 526 sighted adolescents completed the Ego Identity Process Questionnaire. Results: The levels of

  8. Identity Development in German Adolescents with and without Visual Impairments

    ERIC Educational Resources Information Center

    Pinquart, Martin; Pfeiffer, Jens P.

    2013-01-01

    Introduction: The study reported here assessed the exploration of identity and commitment to an identity in German adolescents with and without visual impairments. Methods: In total, 178 adolescents with visual impairments (blindness or low vision) and 526 sighted adolescents completed the Ego Identity Process Questionnaire. Results: The levels of…

  9. Factors Affecting the Reading Media Used by Visually Impaired Adults

    ERIC Educational Resources Information Center

    Goudiras, Dimitrios B.; Papadopoulos, Konstantinos S.; Koutsoklenis, Athanasios Ch.; Papageorgiou, Virginia E.; Stergiou, Maria S.

    2009-01-01

    The aim of this study was to examine reading media (braille, cassettes, screen-reader, screen-magnifier, large print, low vision aids, CCTV) used by visually impaired adults. This article reports the results of a research project involving 100 people with visual impairment. The participants were interviewed and asked to fill in a questionnaire to

  10. Spatio-temporal model for subjective colours based on colour coded ganglion cells.

    PubMed

    Grunfeld, E D; Spitzer, H

    1995-01-01

    We propose a mathematical model for the generation of the subjective colour phenomenon through Benham's disk stimuli. The model relates to the spatial and temporal properties of three colour coded retinal ganglion cells: L+/M-, M+/L- and S-/(L+M)+ [or (L+M)-/S+]. It is suggested that the phenomenon is based on both the opponent mechanisms in the cells' receptive fields, and the "rebound response"--a common cell response to turning off of an inhibitory stimulus (nonlinear cell dynamics). A physiological mechanism is suggested for this response. The integrated cell responses to Benham disk-stimuli create imbalances between the colour pathways that are interpreted as actual colours. The model also predicts the shift in the perceived colours when the disk rotation rate is varied. PMID:7839622

  11. Stereo vision and strabismus

    PubMed Central

    Read, J C A

    2015-01-01

    Binocular stereopsis, or stereo vision, is the ability to derive information about how far away objects are, based solely on the relative positions of the object in the two eyes. It depends on both sensory and motor abilities. In this review, I briefly outline some of the neuronal mechanisms supporting stereo vision, and discuss how these are disrupted in strabismus. I explain, in some detail, current methods of assessing stereo vision and their pros and cons. Finally, I review the evidence supporting the clinical importance of such measurements. PMID:25475234

  12. The Greatest Generation Meets Its Greatest Challenge: Vision Loss and Depression in Older Adults

    ERIC Educational Resources Information Center

    O'Donnell, Coleen

    2005-01-01

    Having lived through the Great Depression and World War II, older adults now face the challenge of vision loss in record numbers. Depression is closely associated with functional loss and social isolation in late-life vision loss. The principles of assisting those who are aging will also benefit those who are aging with a visual impairment. They…

  13. Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Pollmann, Stefan

    2015-01-01

    Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental

  14. Knowledge and Use of Low Vision Services Among Persons with Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Casten, Robin J.; Maloney, Eileen K.; Rovner, Barry W.

    2005-01-01

    Visual impairment (blindness or low vision) is a leading cause of disability among older adults and is most often due to age-related macular degeneration (AMD). It is predicted that 2.95 million people will have AMD by 2020 (Eye Diseases Prevalence Research Group, 2004). Unfortunately, there is no cure for AMD, nor can lost vision be restored.

  15. Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

    ERIC Educational Resources Information Center

    Geringswald, Franziska; Pollmann, Stefan

    2015-01-01

    Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental…

  16. [Cognitive impairment].

    PubMed

    Reuter, F; Audoin, B; Rico, A; Malikova, I; Ranjeva, J-P; Pelletier, J

    2009-03-01

    Cognitive impairment is common in multiple sclerosis (MS), occurring at all stages of the disease, even at the earliest, and can be a major source of disability, social impairment, and impoverished quality of life. Cognitive dysfunction is mainly focused on working memory, conceptual reasoning, verbal fluency, speed of information processing, attention and executive function. Measures of information-processing speed appear to be the most robust and sensitive markers of cognitive impairment in MS patients. Cognitive testing in MS patients is complex and cognitive screening tests are time- and cost-saving test instruments. A comprehensive and sensitive cognitive test procedure should be administered to detect cognitive dysfunction, and recent studies demonstrate that single, predominantly speed-related cognitive tests may be superior to extensive and time-consuming test batteries in screening cognitive decline. Additional clinical factors, including disease course, fatigue, and affective disturbance, can impact the degree of MS-related cognitive impairment. Despite weak correlation with disease duration and physical disability status, the degree of cognitive impairment in MS has been related to the extent of topographically specific neuronal tissue damage and loss. Numerous studies have applied conventional and quantitative magnetic resonance imaging (MRI) techniques to correlate the profile and degree of cognitive impairment with various MRI-detectable abnormalities. The burden of MRI-visible lesions does not fully account for the degree of MS-related cognitive impairment. Nonconventional MRI findings suggest the extent of subtle tissue damage in normal-appearing white and grey matter to correlate best with the severity of cognitive impairment in MS patients. Structural MRI approaches have recently been extended by functional MRI studies scrutinizing the brain's ability for adaptive functional reorganization in the presence of widespread tissue damage. Cognitive impairment in MS seems to be not simply the result of tissue destruction, but also a balance between tissue destruction, tissue repair, and adaptive functional reorganization. These findings highlight the need to screen for cognitive deficits in MS patients to conduct potential cognitive rehabilitation intervention. PMID:19361675

  17. Survey of colourings and preservatives in drugs.

    PubMed Central

    Pollock, I.; Young, E.; Stoneham, M.; Slater, N.; Wilkinson, J. D.; Warner, J. O.

    1989-01-01

    OBJECTIVE--To assess the prevalence of colourings and preservatives in drug formulations in the United Kingdom. DESIGN--Postal survey. PARTICIPANTS--All pharmaceutical manufacturers in the United Kingdom were requested to supply data on drug formulations with particular regard to the content of colourings and preservatives. MAIN OUTCOME MEASURE--Prevalence in proprietary drugs of colourings or preservatives, or both, that have been implicated in adverse reactions. Computation of a list of formulations of bronchodilators, antihistamines, and antibiotics that are free of such additives. RESULTS--A total of 118 out of 120 pharmaceutical companies supplied the data requested. In all, 2204 drug formulations were analysed and found to contain 419 different additives, of which 52 were colourings and preservatives that have been implicated in adverse reactions; 930 formulations contained such an additive. Tartrazine was the fourth most commonly occurring colouring, being present in 124 drug formulations. CONCLUSION--Many drugs contain additives that help to identify them and prolong their shelf life but are implicated in adverse reactions in some people. Some form of labelling of drug additives would enable these people to avoid drugs containing such additives. PMID:2508849

  18. Scalable, full-colour and controllable chromotropic plasmonic printing

    PubMed Central

    Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

    2015-01-01

    Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates controllable chromotropic capability, that is, the ability of reversible colour transformations. This chromotropic capability affords enormous potentials in building functionalized prints for anticounterfeiting, special label, and high-density data encryption storage. With such excellent performances in functional colour applications, this colour-printing approach could pave the way for plasmonic colour printing in real-world commercial utilization. PMID:26567803

  19. Scalable, full-colour and controllable chromotropic plasmonic printing

    NASA Astrophysics Data System (ADS)

    Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

    2015-11-01

    Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates controllable chromotropic capability, that is, the ability of reversible colour transformations. This chromotropic capability affords enormous potentials in building functionalized prints for anticounterfeiting, special label, and high-density data encryption storage. With such excellent performances in functional colour applications, this colour-printing approach could pave the way for plasmonic colour printing in real-world commercial utilization.

  20. Artificial Vision: Vision of a Newcomer

    NASA Astrophysics Data System (ADS)

    Fujikado, Takashi; Sawai, Hajime; Tano, Yasuo

    The Japanese Consortium for an Artificial Retina has developed a new stimulating method named Suprachoroidal-Transretinal Stimulation (STS). Using STS, electrically evoked potentials (EEPs) were effectively elicited in Royal College of Surgeons (RCS) rats and in rabbits and cats with normal vision, using relatively small stimulus currents, such that the spatial resolution appeared to be adequate for a visual prosthesis. The histological analysis showed no damage to the rabbit retina when electrical currents sufficient to elicit distinct EEPs were applied. It was also shown that transcorneal electrical stimulation (TES) to the retina prevented the death of retinal ganglion cells (RGCs). STS, which is less invasive than other retinal prostheses, could be one choice to achieve artificial vision, and the optimal parameters of electrical stimulation may also be effective for the neuroprotection of residual RGCs.

  1. Home vision tests

    MedlinePLUS

    ... testing. AMSLER GRID TEST This test helps detect macular degeneration . This is a disease that causes blurred vision, ... eye exam. People who are at risk of macular degeneration may be told by their ophthalmologist to perform ...

  2. Vision Loss, Sudden

    MedlinePLUS

    ... on where the damage occurs. How and Why Blindness Develops Anything that blocks the passage of light ... to the brain will interfere with vision. Legal blindness is defined as a visual acuity of 20/ ...

  3. The Vision Thing.

    ERIC Educational Resources Information Center

    Marcus, Stephen

    1994-01-01

    Discusses the difficulty of figuring out how to show (not tell) someone what a compelling vision of education might be. Makes predictions about how technology will affect the teaching of writing. Asks readers to formulate their own predictions. (RS)

  4. Living with vision loss

    MedlinePLUS

    ... EH, Katz PR, Malone ML, eds. Practice of Geriatrics . 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap ... Shega JW. Vision loss. In: Wachtel TJ, ed. Geriatric Clinical Advisor: Instant diagnosis and treatment . Philadelphia, PA: ...

  5. Manitoba Vision Screening Study.

    ERIC Educational Resources Information Center

    Rathgeber, Arthur J.

    1981-01-01

    The article describes a vision screening program in Manitoba to identify high-risk children. Organizational strategies, instrumentation, and results of a study of the effectiveness of the screening process with 732 children are detailed. (Author)

  6. Hearing Impairments

    NASA Astrophysics Data System (ADS)

    Cavender, Anna; Ladner, Richard E.

    For many people with hearing impairments, the degree of hearing loss is only a small aspect of their disability and does not necessarily determine the types of accessibility solutions or accommodations that may be required. For some people, the ability to adjust the audio volume may be sufficient. For others, translation to a signed language may be more appropriate. For still others, access to text alternatives may be the best solution. Because of these differences, it is important for researchers in Web accessibility to understand that people with hearing impairments may have very different cultural-linguistic traditions and personal backgrounds.

  7. Capturing Natural-Colour 3D Models of Insects for Species Discovery and Diagnostics

    PubMed Central

    Nguyen, Chuong V.; Lovell, David R.; Adcock, Matt; La Salle, John

    2014-01-01

    Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversitypast, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens from all angles and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. (Natural-colour is used to contrast with false-colour, i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control. PMID:24759838

  8. Capturing natural-colour 3D models of insects for species discovery and diagnostics.

    PubMed

    Nguyen, Chuong V; Lovell, David R; Adcock, Matt; La Salle, John

    2014-01-01

    Collections of biological specimens are fundamental to scientific understanding and characterization of natural diversity-past, present and future. This paper presents a system for liberating useful information from physical collections by bringing specimens into the digital domain so they can be more readily shared, analyzed, annotated and compared. It focuses on insects and is strongly motivated by the desire to accelerate and augment current practices in insect taxonomy which predominantly use text, 2D diagrams and images to describe and characterize species. While these traditional kinds of descriptions are informative and useful, they cannot cover insect specimens "from all angles" and precious specimens are still exchanged between researchers and collections for this reason. Furthermore, insects can be complex in structure and pose many challenges to computer vision systems. We present a new prototype for a practical, cost-effective system of off-the-shelf components to acquire natural-colour 3D models of insects from around 3 mm to 30 mm in length. ("Natural-colour" is used to contrast with "false-colour", i.e., colour generated from, or applied to, gray-scale data post-acquisition.) Colour images are captured from different angles and focal depths using a digital single lens reflex (DSLR) camera rig and two-axis turntable. These 2D images are processed into 3D reconstructions using software based on a visual hull algorithm. The resulting models are compact (around 10 megabytes), afford excellent optical resolution, and can be readily embedded into documents and web pages, as well as viewed on mobile devices. The system is portable, safe, relatively affordable, and complements the sort of volumetric data that can be acquired by computed tomography. This system provides a new way to augment the description and documentation of insect species holotypes, reducing the need to handle or ship specimens. It opens up new opportunities to collect data for research, education, art, entertainment, biodiversity assessment and biosecurity control. PMID:24759838

  9. Why simulations of colour for CVD observers might not be what they seem

    NASA Astrophysics Data System (ADS)

    Green, Phil

    2015-01-01

    A common task in universal design is to create a 'simulation' of the appearance of a colour image as it appears to a CVD observer. Although such simulations are useful in illustrating the particular problems that a CVD observer has in discriminating between colours in an image, it may not be reasonable to assume that such a simulation accurately conveys the experience of the CVD observer to an observer with normal vision. Two problems with this assumption are discussed here. First, it risks confusing appearance with sensation. A colour appearance model can more or less accurately predict the change in appearance of a colour when it is viewed under different conditions, but does not define the actual sensation. Such a sensation cannot be directly communicated but merely located on a scale with other related sensations. In practice we avoid this epistemological problem by asking observers to judge colour matches, relations and differences, none of which requires examination of the sensation itself. Since we do not truly know what sensation a normal observer experiences, it seems unscientific to suppose that we can do so for CVD observers. Secondly, and following from the above, the relation between stimulus and corresponding sensation is established as part of neural development during infancy, and while we can determine the stimulus we cannot readily determine what sensation the stimulus is mapped to, or what the available range of sensations is for a given observer. It is suggested that a similar range of sensations could be available to CVD observers as to normal observers.

  10. Photonic-crystal full-colour displays

    NASA Astrophysics Data System (ADS)

    Arsenault, Andr C.; Puzzo, Daniel P.; Manners, Ian; Ozin, Geoffrey A.

    2007-08-01

    In our information-rich world, it is becoming increasingly important to develop technologies capable of displaying dynamic and changeable data, for reasons ranging from value-added advertising to environmental sustainability. There is an intense drive at the moment towards paper-like displays, devices having a high reflectivity and contrast to provide viewability in a variety of environments, particularly in sunlight where emissive or backlit devices perform very poorly. The list of possible technologies is extensive, including electrophoretic, cholesteric liquid crystalline, electrochromic, electrodewetting, interferometric and more. Despite tremendous advances, the key drawback of all these existing display options relates to colour. As soon as an RGB (red, green and blue) colour filter or spatially modulated colour scheme is implemented, substantial light losses are inevitable even if the intrinsic reflectivity of the material is very good.

  11. The vision trap.

    PubMed

    Langeler, G H

    1992-01-01

    At Mentor Graphics Corporation, Gerry Langeler was the executive responsible for vision, and vision, he discovered, has the power to weaken a strong company. Mentor helped to invent design-automation electronics in the early 1980s, and by the end of the decade, it dominated the industry. In its early days, fighting to survive, Mentor's motto was Build Something People Will Buy. Then when clear competition emerged in the form of Daisy Systems, a startup that initially outsold Mentor, the watchword became Beat Daisy. Both "visions" were pragmatic and immediate. They gave Mentor a sense of purpose as it developed its products and gathered momentum. Once Daisy was beaten, however, company vision began to self-inflate. As Mentor grew more and more successful, Langeler formulated vision statements that were more and more ambitious, grand, and inspirational. The company traded its gritty determination to survive for a dream of future glory. The once explicit call for effective action became a fervid cry for abstract perfection. The first step was Six Boxes, a transitional vision that combined goals for success in six business areas with grandiose plans to compete with IBM at the level of billion-dollar revenues. From there, vision stepped up to the 10X Imperative, a quality-improvement program that focused on arbitrary goals and measures that were, in fact, beyond the company's control. The last escalation came when Mentor Graphics decided to Change the Way the World Designs. The company had stopped making product and was making poetry. Finally, in 1991, after six years of increasing self-infatuation, Mentor hit a wall of decreasing indicators. Langeler, who had long since begun to doubt the value of abstract visions, reinstated Build Something People Will Buy. And Mentor was back to basics, a sense of purpose back to its workplace. PMID:10117368

  12. Synthetic Vision Systems

    NASA Technical Reports Server (NTRS)

    Prinzel, L.J.; Kramer, L.J.

    2009-01-01

    A synthetic vision system is an aircraft cockpit display technology that presents the visual environment external to the aircraft using computer-generated imagery in a manner analogous to how it would appear to the pilot if forward visibility were not restricted. The purpose of this chapter is to review the state of synthetic vision systems, and discuss selected human factors issues that should be considered when designing such displays.

  13. Binocular peripheral vision system

    NASA Astrophysics Data System (ADS)

    Maniere, Thierry; Benosman, Ryad; Gastaud, Claude; Devars, Jean

    1997-04-01

    The observation of the whole space on a 360 degree(s) angle, as well as the reconstruction of a 3D scene, presumed unknown, presents an unquestionable interest in the field of robotic vision. The object of this paper is the description of a system dedicated to binocular peripheral vision, its conception being specifically linked to the problem at stake. The architecture of our system of image capture lies on the key principle which is simplification of calculation.

  14. Emotion-Induced Trade-Offs in Spatiotemporal Vision

    ERIC Educational Resources Information Center

    Bocanegra, Bruno R.; Zeelenberg, Rene

    2011-01-01

    It is generally assumed that emotion facilitates human vision in order to promote adaptive responses to a potential threat in the environment. Surprisingly, we recently found that emotion in some cases impairs the perception of elementary visual features (Bocanegra & Zeelenberg, 2009b). Here, we demonstrate that emotion improves fast temporal

  15. Environmental and Personal Safety: No Vision Required. Practice Report

    ERIC Educational Resources Information Center

    Bozeman, Laura A.

    2004-01-01

    Personal safety is an important issue for all people, regardless of their physical capabilities. For people with visual impairments (that is, those who are blind or have low vision), real concerns exist regarding their vulnerability to crime and their greater risk of attack. With a nationwide increase in crime in the United States, "Three out of

  16. Emotion-Induced Trade-Offs in Spatiotemporal Vision

    ERIC Educational Resources Information Center

    Bocanegra, Bruno R.; Zeelenberg, Rene

    2011-01-01

    It is generally assumed that emotion facilitates human vision in order to promote adaptive responses to a potential threat in the environment. Surprisingly, we recently found that emotion in some cases impairs the perception of elementary visual features (Bocanegra & Zeelenberg, 2009b). Here, we demonstrate that emotion improves fast temporal…

  17. The Impact of Vision Loss on Personality Traits

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos S.; Koustriava, Eleni; Charalampidou, Maria; Gerapostolou, Ioanna

    2013-01-01

    The aim of this study is to explore the differences in personality traits amongst adults with blindness, adults with low vision and sighted adults. Moreover, the relationship between the four scales of Eysenck's personality questionnaire and the demographic characteristics of participants with visual impairments was examined. There are no…

  18. OCoc- from Ocean Colour to Organic Carbon

    NASA Astrophysics Data System (ADS)

    Heim, B.; Overduin, P. P.; Schirrmeister, L.; Lantuit, H.; Doerffer, R.

    2009-12-01

    Enhanced permafrost warming and increased arctic river discharges have heightened concern about the input of terrigenous matter into Arctic coastal waters. The OCoc-from Ocean Colour to Organic Carbon project (IPY-project 1176), funded by the German Research Foundation (DFG), is an Ocean Colour study joined with the Arctic Coastal Dynamics ACD network and Arctic Circum-polar Coastal Observatory Network ACCO-Net (IPY-project 90). OCoc uses Ocean Colour satellite data for synoptical monitoring of organic matter fluxes from fluvial and coastal sources. Initial results from German-Russian expeditions at the southeastern Laptev Sea Coast (Arctic Siberia, Russia) in August 2008 and August 2009 are presented. Large parts of this coastal zone are characterized by highly erosive organic-rich material. Ocean Colour MERIS Reduced Resolution (RR)-LIB data of the have been processed towards optical aquatic parameters using Beam-Visat4.2 and the MERIS case2 regional processor for coastal application (C2R). Calculated aquatic parameters are absorption and backscattering coefficients, apparent optical properties such as the first attenuation depth (Z90) and calculated concentrations of chlorophyll, total suspended matter and coloured dissolved organic matter absorption from the water leaving reflectances. Initial comparisons with expedition data (Secchi depths, cDOM) show that the MERIS-C2R optical parameters total absorption and the first attenuation depth, Z90, seem adequately to represent true conditions. High attenuation values in the spectral blue wavelength range may serve as tracer for the organic-rich terrigenous input. The synoptic information of Ocean Colour products will provide valuable spatial and dynamical information on the Organic Carbon and sediment fluxes from the Siberian permafrost coast.

  19. Biofeedback for Better Vision

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Biofeedtrac, Inc.'s Accommotrac Vision Trainer, invented by Dr. Joseph Trachtman, is based on vision research performed by Ames Research Center and a special optometer developed for the Ames program by Stanford Research Institute. In the United States, about 150 million people are myopes (nearsighted), who tend to overfocus when they look at distant objects causing blurry distant vision, or hyperopes (farsighted), whose vision blurs when they look at close objects because they tend to underfocus. The Accommotrac system is an optical/electronic system used by a doctor as an aid in teaching a patient how to contract and relax the ciliary body, the focusing muscle. The key is biofeedback, wherein the patient learns to control a bodily process or function he is not normally aware of. Trachtman claims a 90 percent success rate for correcting, improving or stopping focusing problems. The Vision Trainer has also proved effective in treating other eye problems such as eye oscillation, cross eyes, and lazy eye and in professional sports to improve athletes' peripheral vision and reaction time.

  20. Principal components colour display of ERTS imagery

    NASA Technical Reports Server (NTRS)

    Taylor, M. M.

    1974-01-01

    In the technique presented, colours are not derived from single bands, but rather from independent linear combinations of the bands. Using a simple model of the processing done by the visual system, three informationally independent linear combinations of the four ERTS bands are mapped onto the three visual colour dimensions of brightness, redness-greenness and blueness-yellowness. The technique permits user-specific transformations which enhance particular features, but this is not usually needed, since a single transformation provides a picture which conveys much of the information implicit in the ERTS data. Examples of experimental vector images with matched individual band images are shown.

  1. Colours in a complex fluid flow

    NASA Astrophysics Data System (ADS)

    Carlomagno, Giovanni Maria

    2006-06-01

    The addition of colours to flow visualization allows a third dimension to be added to the intrinsically two-dimensional information rendered by an image. In the present work, the velocity domain and the wall heat transfer in the near field of a jet in cross-flow is experimentally investigated by making extensive use of coloured images. Tests are performed in a low turbulence wind tunnel at a jet Reynolds number equal to 8000 and for velocity ratios ranging from 1 to 5. Data are obtained with Particle Image Velocimetry (PIV) and with infrared thermography applied to the steady state heated-thin-foil technique.

  2. Two-year evolution of perchloroethylene-induced color-vision loss

    SciTech Connect

    Gobba, F.; Righi, E.; Fantuzzi, G.; Predieri, G.; Cavazzuti, L.; Aggazzotti, G.

    1998-05-01

    Progression of perchloroethylene-induced color-vision impairment was studied in 33 dry-cleaner workers at 12 establishments in Modena, Italy. In an initial survey, the authors evaluated exposure with personal passive samplers, and they assessed color vision with the Lanthony D-15 desaturated panel. Two years later, workers were reexamined. In 19 workers (subgroup A), exposure to perchloroethylene had increased, whereas in the remaining 14 workers (subgroup B) exposure was reduced. Color vision worsened in subgroup A, but no vision changes were apparent in subgroup B. The results indicated that an increase in exposure during a 2-y period, even if slight, can cause color vision to deteriorate. A similar slight reduction in exposure did not lead to color-vision improvement; perhaps this lack of improvement resulted from (a) an insufficient reduction in exposure, (b) an insufficient reduction in duration of exposure, or (c) irreversible perchloroethylene-induced color-vision loss.

  3. Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients

    PubMed Central

    Aktas, Guliz; Sahin, Erdal; Vallittu, Pekka; zcan, Mutlu; Lassila, Lippo

    2013-01-01

    This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6mm7mm7mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2). Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n=16) acted as the control group. Coreveneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5mm?min?1). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.78)MPa than all other tested groups ((27.14.1)?(39.74.7) and (27.45.6)?(35.94.7)MPa with and without colouring, respectively) (P<0.001). While in zirconiaveneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering <1/3 of the substrate surface, in the metalceramic group, veneering ceramic was left adhered >1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the coreveneer adhesion. Metalceramic adhesion was more reliable than all zirconiaveneer ceramics tested. PMID:24158142

  4. Impaired Driving

    MedlinePLUS

    ... people were killed in alcohol-impaired driving crashes, accounting for nearly one-third (31%) of all traffic- ... than were drivers with no alcohol in their system. (7% and 1%, respectively). 1 Top of ... Safe Driving Board on Pinterest Help spread ...

  5. Federal regulation of vision enhancement devices for normal and abnormal vision

    NASA Astrophysics Data System (ADS)

    Drum, Bruce

    2006-09-01

    The Food and Drug Administration (FDA) evaluates the safety and effectiveness of medical devices and biological products as well as food and drugs. The FDA defines a device as a product that is intended, by physical means, to diagnose, treat, or prevent disease, or to affect the structure or function of the body. All vision enhancement devices fulfill this definition because they are intended to affect a function (vision) of the body. In practice, however, FDA historically has drawn a distinction between devices that are intended to enhance low vision as opposed to normal vision. Most low vision aids are therapeutic devices intended to compensate for visual impairment, and are actively regulated according to their level of risk to the patient. The risk level is usually low (e.g. Class I, exempt from 510(k) submission requirements for magnifiers that do not touch the eye), but can be as high as Class III (requiring a clinical trial and Premarket Approval (PMA) application) for certain implanted and prosthetic devices (e.g. intraocular telescopes and prosthetic retinal implants). In contrast, the FDA usually does not actively enforce its regulations for devices that are intended to enhance normal vision, are low risk, and do not have a medical intended use. However, if an implanted or prosthetic device were developed for enhancing normal vision, the FDA would likely decide to regulate it actively, because its intended use would entail a substantial medical risk to the user. Companies developing such devices should contact the FDA at an early stage to clarify their regulatory status.

  6. Stimulation of functional vision in children with perinatal brain damage.

    PubMed

    Alimovi?, Sonja; Mejaski-Bosnjak, Vlatka

    2011-01-01

    Cerebral visual impairment (CVI) is one of the most common causes of bilateral visual loss, which frequently occurs due to perinatal brain injury. Vision in early life has great impact on acquisition of basic comprehensions which are fundamental for further development. Therefore, early detection of visual problems and early intervention is necessary. The aim of the present study is to determine specific visual functioning of children with perinatal brain damage and the influence of visual stimulation on development of functional vision at early age of life. We initially assessed 30 children with perinatal brain damage up to 3 years of age, who were reffered to our pediatric low vision cabinet in "Little house" from child neurologists, ophthalmologists Type and degree of visual impairment was determined according to functional vision assessment of each child. On the bases of those assessments different kind of visual stimulations were carried out with children who have been identified to have a certain visual impairment. Through visual stimulation program some of the children were stimulated with light stimulus, some with different materials under the ultraviolet (UV) light, and some with bright color and high contrast materials. Children were also involved in program of early stimulation of overall sensory motor development. Goals and methods of therapy were determined individually, based on observation of child's possibilities and need. After one year of program, reassessment was done. Results for visual functions and functional vision were compared to evaluate the improvement of the vision development. These results have shown that there was significant improvement in functional vision, especially in visual attention and visual communication. PMID:21648304

  7. Pedestrian cue detection: colour inverse maximum likelihood ratio

    NASA Astrophysics Data System (ADS)

    Braik, Malik; Pycock, David

    2013-12-01

    This paper presents an adaptable method for identifying pedestrian cues. Cue detection is investigated for adults in isolation and groups. The aim is to detect a single cue for each pedestrian. Colour Inverse Maximum Likelihood Ratio (IMLR) criteria are employed to distinguish object and background regions using a mask designed to accommodate a wide range of appearances. The adaptability and specificity of the method is demonstrated using images containing trees and street furniture; structures that are often confused with pedestrians by computer vision systems. Test images of low contrast are also included to assess the sensitivity of the cue detection process. Evaluation with over 250 images gives a false positive error rate of 10% and a false negative error rate of 1.5% % under exacting detection criteria with a complexity of where n is the number of image points considered. The speed of execution is 8 mS per frame for images of 640 by 480 pixels on an Intel core i3-2310MTM CPU running at 2.10GHz with 4.00GB RAM.

  8. Advanced colour processing for mobile devices

    NASA Astrophysics Data System (ADS)

    Gillich, Eugen; Drksen, Helene; Lohweg, Volker

    2015-02-01

    Mobile devices such as smartphones are going to play an important role in professionally image processing tasks. However, mobile systems were not designed for such applications, especially in terms of image processing requirements like stability and robustness. One major drawback is the automatic white balance, which comes with the devices. It is necessary for many applications, but of no use when applied to shiny surfaces. Such an issue appears when image acquisition takes place in differently coloured illuminations caused by different environments. This results in inhomogeneous appearances of the same subject. In our paper we show a new approach for handling the complex task of generating a low-noise and sharp image without spatial filtering. Our method is based on the fact that we analyze the spectral and saturation distribution of the channels. Furthermore, the RGB space is transformed into a more convenient space, a particular HSI space. We generate the greyscale image by a control procedure that takes into account the colour channels. This leads in an adaptive colour mixing model with reduced noise. The results of the optimized images are used to show how, e. g., image classification benefits from our colour adaptation approach.

  9. Demonstration of the Colour Range of Indicators

    ERIC Educational Resources Information Center

    Woods, G. T.

    1975-01-01

    Describes the construction of a box that is filled with indicator of a particular concentration. A little acid is added to one side and a little alkali to the other so that the complete colour range of the indicator is observable. (GS)

  10. Supersymmetric coloured/hairy black holes

    NASA Astrophysics Data System (ADS)

    Meessen, Patrick

    2008-07-01

    We discuss all possible spherically symmetric black hole type solutions to an N = 2 supergravity model with SO (3) gauging. The solutions consist of a one parameter family of black hole solutions evading the no-hair theorem and an isolated solution that is a supersymmetric analogue of a coloured black hole.

  11. New Evidence for Infant Colour Categories

    ERIC Educational Resources Information Center

    Franklin, Anna; Davies, Ian R. L.

    2004-01-01

    Bornstein, Kessen, and Weiskopf (1976) reported that pre-linguistic infants perceive colour categorically for primary boundaries: Following habituation, dishabituation only occurred if the test stimulus was from a different adult category to the original. Here, we replicated this important study and extended it to include secondary boundaries,

  12. New Evidence for Infant Colour Categories

    ERIC Educational Resources Information Center

    Franklin, Anna; Davies, Ian R. L.

    2004-01-01

    Bornstein, Kessen, and Weiskopf (1976) reported that pre-linguistic infants perceive colour categorically for primary boundaries: Following habituation, dishabituation only occurred if the test stimulus was from a different adult category to the original. Here, we replicated this important study and extended it to include secondary boundaries,…

  13. Quantum entanglement of quark colour states

    SciTech Connect

    Buividovich, P. V.; Kuvshinov, V. I.

    2010-03-24

    An analysis of quantum entanglement between the states of static colour charges in the vacuum of pure Yang-Mills theory is carried out. Hilbert space of physical states of the fields and the charges is endowed with a direct product structure by attaching an infinite Dirac string to each charge.

  14. Colour thresholding and objective quantification in bioimaging

    NASA Technical Reports Server (NTRS)

    Fermin, C. D.; Gerber, M. A.; Torre-Bueno, J. R.

    1992-01-01

    Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples.

  15. Whorfian effects on colour memory are not reliable.

    PubMed

    Wright, Oliver; Davies, Ian R L; Franklin, Anna

    2015-01-01

    The Whorfian hypothesis suggests that differences between languages cause differences in cognitive processes. Support for this idea comes from studies that find that patterns of colour memory errors made by speakers of different languages align with differences in colour lexicons. The current study provides a large-scale investigation of the relationship between colour language and colour memory, adopting a cross-linguistic and developmental approach. Colour memory on a delayed matching-to-sample (XAB) task was investigated in 2 language groups with differing colour lexicons, for 3 developmental stages and 2 regions of colour space. Analyses used a Bayesian technique to provide simultaneous assessment of two competing hypotheses (H1-Whorfian effect present, H0-Whorfian effect absent). Results of the analyses consistently favoured H0. The findings suggest that Whorfian effects on colour memory are not reliable and that the importance of such effects should not be overestimated. PMID:25230782

  16. Colour preferences influences odour learning in the hawkmoth, Macroglossum stellatarum

    NASA Astrophysics Data System (ADS)

    Balkenius, Anna; Kelber, Almut

    2006-05-01

    The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed.

  17. Insect vision as model for machine vision

    NASA Astrophysics Data System (ADS)

    Osorio, D.; Sobey, Peter J.

    1992-11-01

    The neural architecture, neurophysiology and behavioral abilities of insect vision are described, and compared with that of mammals. Insects have a hardwired neural architecture of highly differentiated neurons, quite different from the cerebral cortex, yet their behavioral abilities are in important respects similar to those of mammals. These observations challenge the view that the key to the power of biological neural computation is distributed processing by a plastic, highly interconnected, network of individually undifferentiated and unreliable neurons that has been a dominant picture of biological computation since Pitts and McCulloch's seminal work in the 1940's.

  18. Effectiveness of low vision services in improving patient quality of life at Aravind Eye Hospital

    PubMed Central

    Do, Anna T; Ilango, Krishanmurthy; Ramasamy, Dhivya; Kalidasan, Suriya; Balakrishnan, Vijayakumar; Chang, Robert T

    2014-01-01

    Context: In India, where the heavy burden of visual impairment exists, low vision services are scarce and under-utilized. Aims: Our study was designed to survey the effectiveness of low vision exams and visual aids in improving patient quality of life in southern rural India. Subjects and Methods: The low vision quality of life (LVQOL) questionnaire measures vision-related quality of life through 25 questions on a Likert scale of 05 that pertain to (1) mobility, distance vision, and lighting; (2) psychological adjustment; (3) reading and fine work; and (4) activities of daily living. This tool was translated into Tamil and verbally administered to 55 new low vision referral patients before their first visit at the low vision clinic at Aravind Eye Hospital. Low vision aids (LVAs) were prescribed at the discretion of the low vision specialist. 1-month later, the same questionnaire was administered over the phone. Results: About 44 of 55 low vision patients completed baseline and follow-up LVQOL surveys, and 30 normal vision controls matched for age, gender, and education were also surveyed (average 117.34 points). After the low vision clinic visit, the low vision group demonstrated a 4.55-point improvement in quality of life (from 77.77 to 82.33 points, P = 0.001). Adjusting for age, gender, and education, the low vision patients who also received LVAs (n = 24) experienced an even larger increase than those who did not (n = 20) (8.89 points, P < 0.001). Conclusion: Low vision services and visual aids can improve the quality of life in South Indian rural population regardless of age, gender, and education level. Thus, all low vision patients who meet the criteria should be referred for evaluation. PMID:25579355

  19. Adaptation to Low Vision Caused by Age-Related Macular Degeneration: A Case Study

    ERIC Educational Resources Information Center

    Smith, Theresa Marie

    2008-01-01

    One in eight Americans aged 65 and older has an eye disease resulting in low vision, and more women than men are visually impaired, mainly because women live longer. Age-related visual impairments are an indicator of a decline in activities of daily living and self-help skills. The top eye conditions that affect older adults are macular…

  20. Adaptation to Low Vision Caused by Age-Related Macular Degeneration: A Case Study

    ERIC Educational Resources Information Center

    Smith, Theresa Marie

    2008-01-01

    One in eight Americans aged 65 and older has an eye disease resulting in low vision, and more women than men are visually impaired, mainly because women live longer. Age-related visual impairments are an indicator of a decline in activities of daily living and self-help skills. The top eye conditions that affect older adults are macular

  1. Piaget's Water-Level Task: The Impact of Vision on Performance

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni

    2011-01-01

    In the present study, the aim was to examine the differences in performance between children and adolescents with visual impairment and sighted peers in the water-level task. Twenty-eight individuals with visual impairments, 14 individuals with blindness and 14 individuals with low vision, and 28 sighted individuals participated in the present

  2. Piaget's Water-Level Task: The Impact of Vision on Performance

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Koustriava, Eleni

    2011-01-01

    In the present study, the aim was to examine the differences in performance between children and adolescents with visual impairment and sighted peers in the water-level task. Twenty-eight individuals with visual impairments, 14 individuals with blindness and 14 individuals with low vision, and 28 sighted individuals participated in the present…

  3. Colour-the-INSight: combining a direct view rifle sight with fused intensified and thermal imagery

    NASA Astrophysics Data System (ADS)

    Hogervorst, M. A.; Jansen, C.; Toet, A.; Bijl, P.; Bakker, P.; Hiddema, A. C.; van Vliet, S. F.

    2012-06-01

    We present the design and evaluation of a new demonstrator rifle sight viewing system containing direct view, red aim point and fusion of an (uncooled, LWIR) thermal sensor with a digital image intensifier. Our goal is to create a system that performs well under a wide variety of (weather) conditions during daytime and nighttime and combines the advantages of the various sensor systems. A real-time colour image with salient hot targets is obtained from the night vision sensors by implementing the Colour-the-Night fusion method (Hogervorst & Toet, 2010) on the on-board processor. The prototype system was evaluated in a series of field trials with military observers performing detection and identification tasks. The tests showed that during daytime the addition of a thermal image to direct vision is advantageous, e.g. for the detection of hot targets. At nighttime, the fusion of thermal and image intensified imagery results in increased situational awareness and improved detection of (hot) targets. For identification of small (handheld) objects, the technology needs to be further refined.

  4. Functional Vision Disorder.

    PubMed

    Egan, Robert A; LaFrance, W Curt

    2015-10-01

    Functional vision disorder (FVD) is a common problem seen in many neurologic and ophthalmologic practitioners' offices and may occur in isolation or in the presence of medical illness. This disorder presents with visual or oculomotor symptoms and manifests as vision loss in one or both eyes, visual field loss, double vision, oscillopsia, anisocoria, blepharospasm, or ptosis. Manual perimetry is the most effective method for determining functional visual loss, and the presence of a central scotoma in a functional visual field signifies that a neuropathophysiologic process is almost certainly present. The exact neuropathophysiologic mechanism of this disorder is unknown; however, information can be drawn from the small studies of FVD samples and studies examining neuropsychiatric factors in other conversion disorder semiologies. Psychological and psychiatric interventions can be useful in treating these patients. PMID:26444401

  5. Overview of sports vision

    NASA Astrophysics Data System (ADS)

    Moore, Linda A.; Ferreira, Jannie T.

    2003-03-01

    Sports vision encompasses the visual assessment and provision of sports-specific visual performance enhancement and ocular protection for athletes of all ages, genders and levels of participation. In recent years, sports vision has been identified as one of the key performance indicators in sport. It is built on four main cornerstones: corrective eyewear, protective eyewear, visual skills enhancement and performance enhancement. Although clinically well established in the US, it is still a relatively new area of optometric specialisation elsewhere in the world and is gaining increasing popularity with eyecare practitioners and researchers. This research is often multi-disciplinary and involves input from a variety of subject disciplines, mainly those of optometry, medicine, physiology, psychology, physics, chemistry, computer science and engineering. Collaborative research projects are currently underway between staff of the Schools of Physics and Computing (DIT) and the Academy of Sports Vision (RAU).

  6. Efficient detection of wound-bed and peripheral skin with statistical colour models.

    PubMed

    Veredas, Francisco J; Mesa, Hctor; Morente, Laura

    2015-04-01

    A pressure ulcer is a clinical pathology of localised damage to the skin and underlying tissue caused by pressure, shear or friction. Reliable diagnosis supported by precise wound evaluation is crucial in order to success on treatment decisions. This paper presents a computer-vision approach to wound-area detection based on statistical colour models. Starting with a training set consisting of 113 real wound images, colour histogram models are created for four different tissue types. Back-projections of colour pixels on those histogram models are used, from a Bayesian perspective, to get an estimate of the posterior probability of a pixel to belong to any of those tissue classes. Performance measures obtained from contingency tables based on a gold standard of segmented images supplied by experts have been used for model selection. The resulting fitted model has been validated on a training set consisting of 322 wound images manually segmented and labelled by expert clinicians. The final fitted segmentation model shows robustness and gives high mean performance rates [(AUC: .9426 (SD .0563); accuracy: .8777 (SD .0799); F-score: 0.7389 (SD .1550); Cohen's kappa: .6585 (SD .1787)] when segmenting significant wound areas that include healing tissues. PMID:25564183

  7. Blue colour preference in honeybees distracts visual attention for learning closed shapes.

    PubMed

    Morawetz, Linde; Svoboda, Alexander; Spaethe, Johannes; Dyer, Adrian G

    2013-10-01

    Spatial vision is an important cue for how honeybees (Apis mellifera) find flowers, and previous work has suggested that spatial learning in free-flying bees is exclusively mediated by achromatic input to the green photoreceptor channel. However, some data suggested that bees may be able to use alternative channels for shape processing, and recent work shows conditioning type and training length can significantly influence bee learning and cue use. We thus tested the honeybees' ability to discriminate between two closed shapes considering either absolute or differential conditioning, and using eight stimuli differing in their spectral characteristics. Consistent with previous work, green contrast enabled reliable shape learning for both types of conditioning, but surprisingly, we found that bees trained with appetitive-aversive differential conditioning could additionally use colour and/or UV contrast to enable shape discrimination. Interestingly, we found that a high blue contrast initially interferes with bee shape learning, probably due to the bees innate preference for blue colours, but with increasing experience bees can learn a variety of spectral and/or colour cues to facilitate spatial learning. Thus, the relationship between bee pollinators and the spatial and spectral cues that they use to find rewarding flowers appears to be a more rich visual environment than previously thought. PMID:23918312

  8. Coloured Filters Enhance the Visual Perception of Social Cues in Children with Autism Spectrum Disorders

    PubMed Central

    Ludlow, Amanda K.; Taylor-Whiffen, Elaine; Wilkins, Arnold J.

    2012-01-01

    Coloured filters have been found to reduce visual distortion of text in children with autism spectrum disorders (ASD). We investigated the effect of the overlays on the mind in the eye task in children with ASD and controls matched for age, gender, and nonverbal IQ. Children were shown photographs of the periocular region of various faces and were asked to judge which emotion was being expressed in the eyes. In children with ASD, the perception of the emotion was significantly improved when the photograph was covered by a coloured overlay. The improvement was significantly greater than in the controls, who showed no significant effect of the overlay. A perceptual impairment may contribute to the social difficulties shown in ASD. PMID:22523702

  9. Intravenous cannulae colour coding. A perennial source of confusion.

    PubMed

    Tordoff, S G; Sweeney, B P

    1990-05-01

    There is no standard colour code for intravenous cannulae in the United Kingdom. A questionnaire was sent to the manufacturers to compile a table of available cannulae, and to assess their views and plans with regard to colour coding. Present moves to establish an international standard are outlined. A simple colour coding standard is proposed. PMID:2356937

  10. Teaching the Absorption of Light Colours Using an Artificial Rainbow

    ERIC Educational Resources Information Center

    Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

    2015-01-01

    This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the

  11. An Interaction of Screen Colour and Lesson Task in CAL

    ERIC Educational Resources Information Center

    Clariana, Roy B.

    2004-01-01

    Colour is a common feature in computer-aided learning (CAL), though the instructional effects of screen colour are not well understood. This investigation considers the effects of different CAL study tasks with feedback on posttest performance and on posttest memory of the lesson colour scheme. Graduate students (n=68) completed a computer-based

  12. Colour histogram analysis for melanoma discrimination in clinical images

    PubMed Central

    Faziloglu, Yunus; Stanley, R. Joe; Moss, Randy H.; Van Stoecker, William; McLean, Rob P.

    2011-01-01

    Background Malignant melanoma, the most deadly form of skin cancer, has a good prognosis if treated in the curable early stages. Colour provides critical discriminating information for the diagnosis of malignant melanoma. Methods This research introduces a three-dimensional relative colour histogram analysis technique to identify colours characteristic of melanomas and then applies these melanoma colours to differentiate benign skin lesions from melanomas. The relative colour of a skin lesion is determined based on subtracting a representative colour of the surrounding skin from each lesion pixel. Acolour mapping for melanoma colours is determined using a training set of images. Apercent melanoma colour feature, defined as the percentage of the lesion pixels that are melanoma colours, is used for discriminating melanomas from benign lesions. The technique is evaluated using a clinical image data set of 129 malignant melanomas and 129 benign lesions consisting of 40 seborrheic keratoses and 89 nevocellular nevi. Results Using the percent melanoma colour feature for discrimination, experimental results yield correct melanoma and benign lesion discrimination rates of 84.3 and 83.0%, respectively. Conclusions The results presented in this work suggest that lesion colour in clinical images is strongly related to the presence of melanoma in that lesion. However, colour information should be combined with other information in order to further reduce the false negative and false positive rates. PMID:12709133

  13. Teaching the Absorption of Light Colours Using an Artificial Rainbow

    ERIC Educational Resources Information Center

    Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

    2015-01-01

    This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

  14. Low Cost Night Vision System for Intruder Detection

    NASA Astrophysics Data System (ADS)

    Ng, Liang S.; Yusoff, Wan Azhar Wan; R, Dhinesh; Sak, J. S.

    2016-02-01

    The growth in production of Android devices has resulted in greater functionalities as well as lower costs. This has made previously more expensive systems such as night vision affordable for more businesses and end users. We designed and implemented robust and low cost night vision systems based on red-green-blue (RGB) colour histogram for a static camera as well as a camera on an unmanned aerial vehicle (UAV), using OpenCV library on Intel compatible notebook computers, running Ubuntu Linux operating system, with less than 8GB of RAM. They were tested against human intruders under low light conditions (indoor, outdoor, night time) and were shown to have successfully detected the intruders.

  15. Bio-inspired vision

    NASA Astrophysics Data System (ADS)

    Posch, C.

    2012-01-01

    Nature still outperforms the most powerful computers in routine functions involving perception, sensing and actuation like vision, audition, and motion control, and is, most strikingly, orders of magnitude more energy-efficient than its artificial competitors. The reasons for the superior performance of biological systems are subject to diverse investigations, but it is clear that the form of hardware and the style of computation in nervous systems are fundamentally different from what is used in artificial synchronous information processing systems. Very generally speaking, biological neural systems rely on a large number of relatively simple, slow and unreliable processing elements and obtain performance and robustness from a massively parallel principle of operation and a high level of redundancy where the failure of single elements usually does not induce any observable system performance degradation. In the late 1980`s, Carver Mead demonstrated that silicon VLSI technology can be employed in implementing ``neuromorphic'' circuits that mimic neural functions and fabricating building blocks that work like their biological role models. Neuromorphic systems, as the biological systems they model, are adaptive, fault-tolerant and scalable, and process information using energy-efficient, asynchronous, event-driven methods. In this paper, some basics of neuromorphic electronic engineering and its impact on recent developments in optical sensing and artificial vision are presented. It is demonstrated that bio-inspired vision systems have the potential to outperform conventional, frame-based vision acquisition and processing systems in many application fields and to establish new benchmarks in terms of redundancy suppression/data compression, dynamic range, temporal resolution and power efficiency to realize advanced functionality like 3D vision, object tracking, motor control, visual feedback loops, etc. in real-time. It is argued that future artificial vision systems, if they are to succeed in demanding applications such as autonomous robot navigation, micro-manipulation or high-speed tracking, must exploit the power of the asynchronous, frame-free, biomimetic approach.

  16. Telescopic vision contact lens

    NASA Astrophysics Data System (ADS)

    Tremblay, Eric J.; Beer, R. Dirk; Arianpour, Ashkan; Ford, Joseph E.

    2011-03-01

    We present the concept, optical design, and first proof of principle experimental results for a telescopic contact lens intended to become a visual aid for age-related macular degeneration (AMD), providing magnification to the user without surgery or external head-mounted optics. Our contact lens optical system can provide a combination of telescopic and non-magnified vision through two independent optical paths through the contact lens. The magnified optical path incorporates a telescopic arrangement of positive and negative annular concentric reflectors to achieve 2.8x - 3x magnification on the eye, while light passing through a central clear aperture provides unmagnified vision.

  17. Vision in elasmobranchs and their relatives: 21st century advances.

    PubMed

    Lisney, T J; Theiss, S M; Collin, S P; Hart, N S

    2012-04-01

    This review identifies a number of exciting new developments in the understanding of vision in cartilaginous fishes that have been made since the turn of the century. These include the results of studies on various aspects of the visual system including eye size, visual fields, eye design and the optical system, retinal topography and spatial resolving power, visual pigments, spectral sensitivity and the potential for colour vision. A number of these studies have covered a broad range of species, thereby providing valuable information on how the visual systems of these fishes are adapted to different environmental conditions. For example, oceanic and deep-sea sharks have the largest eyes amongst elasmobranchs and presumably rely more heavily on vision than coastal and benthic species, while interspecific variation in the ratio of rod and cone photoreceptors, the topographic distribution of the photoreceptors and retinal ganglion cells in the retina and the spatial resolving power of the eye all appear to be closely related to differences in habitat and lifestyle. Multiple, spectrally distinct cone photoreceptor visual pigments have been found in some batoid species, raising the possibility that at least some elasmobranchs are capable of seeing colour, and there is some evidence that multiple cone visual pigments may also be present in holocephalans. In contrast, sharks appear to have only one cone visual pigment. There is evidence that ontogenetic changes in the visual system, such as changes in the spectral transmission properties of the lens, lens shape, focal ratio, visual pigments and spatial resolving power, allow elasmobranchs to adapt to environmental changes imposed by habitat shifts and niche expansion. There are, however, many aspects of vision in these fishes that are not well understood, particularly in the holocephalans. Therefore, this review also serves to highlight and stimulate new research in areas that still require significant attention. PMID:22497415

  18. Interpreting the colour of an estuary

    NASA Astrophysics Data System (ADS)

    Bowers, D. G.; Evans, D.; Thomas, D. N.; Ellis, K.; Williams, P. J. le B.

    2004-01-01

    This paper explores the possibility of using water colour to quantify the concentration of coloured dissolved organic matter (CDOM), and through it, dissolved organic carbon (DOC) and salinity in a turbid estuary in which suspended sediments also influence water colour. The motivation of the work is that the method could be applied to water colour measurements made remotely from an aircraft (or, in larger estuaries, a satellite) enabling near-synoptic mapping of surface salinity and DOC distributions. The paper describes observations at 29 stations distributed along the salinity gradient of the Conwy estuary in North Wales. At each station, surface water samples were collected and analysed for salinity, concentrations of DOC, chlorophyll and suspended particles and absorption spectra of CDOM, or yellow substance. Profiles were made of both upwelling and downwelling irradiance in four narrow band channels, and these were used to calculate irradiance reflection and attenuation coefficients. Results show that spectrally averaged light absorption in the estuary is caused principally and equally by mineral suspended solids and yellow substance, with water and chlorophyll in third and fourth place. The CDOM is strongly correlated ( R2=0.99) in a negative sense with salinity, and more weakly correlated with DOC. There is a linear relationship between CDOM and the ratio of reflection coefficients in the red (670 nm) and blue-green (490 nm) parts of the spectrum, which could be applied to remote sensing; the slope and intercept of the relationship are however different to those found in less turbid water bodies. It is shown that the change in slope and intercept are consistent with the presence, in the Conwy estuary, of suspended particles which influence the water colour. A method is described and tested for inverting water colour measurements in a turbid estuary to give estimates of CDOM in the presence of suspended particles. The solution, which has not been adjusted to fit the data, produces profiles of CDOM, DOC and salinity, which behave reasonably but which currently have a limited accuracy. RMS differences between measured and optically derived parameters for the entire data set are 0.27 m -1 (CDOM), 4 PSU (salinity) and 67 ?M (DOC) although better accuracy is obtained on individual surveys. The fact that there is little bias between predicted and observed parameters indicates that much of the scatter is caused by random measurement error and that the approach is fundamentally sound.

  19. "We Are Multiculturalism": A Self-Study of Faculty of Colour with Pre-Service Teachers of Colour

    ERIC Educational Resources Information Center

    Prado-Olmos, Patricia; Rios, Francisco; Castaneda, Lillian Vega

    2007-01-01

    This paper reports a self-study of three faculty of colour engaged in teaching a special summer session geared to recruiting people of colour to teaching. Given our past experiences in institutions of higher education, we recognised the unique situation and potential of faculty of colour teaching a class made up almost exclusively of students of

  20. Grounding Our Vision: Brain Research and Strategic Vision

    ERIC Educational Resources Information Center

    Walker, Mike

    2011-01-01

    While recognizing the value of "vision," it could be argued that vision alone--at least in schools--is not enough to rally the financial and emotional support required to translate an idea into reality. A compelling vision needs to reflect substantive, research-based knowledge if it is to spark the kind of strategic thinking and insight capable of

  1. Grounding Our Vision: Brain Research and Strategic Vision

    ERIC Educational Resources Information Center

    Walker, Mike

    2011-01-01

    While recognizing the value of "vision," it could be argued that vision alone--at least in schools--is not enough to rally the financial and emotional support required to translate an idea into reality. A compelling vision needs to reflect substantive, research-based knowledge if it is to spark the kind of strategic thinking and insight capable of…

  2. The Colour of the Young Universe

    NASA Astrophysics Data System (ADS)

    2003-12-01

    VLT study gives insight on the evolution of the star formation rate Summary An international team of astronomers [1] has determined the colour of the Universe when it was very young. While the Universe is now kind of beige, it was much bluer in the distant past , at a time when it was only 2,500 million years old. This is the outcome of an extensive and thorough analysis of more than 300 galaxies seen within a small southern sky area, the so-called Hubble Deep Field South. The main goal of this advanced study was to understand how the stellar content of the Universe was assembled and has changed over time. Dutch astronomer Marijn Franx , a team member from the Leiden Observatory (The Netherlands), explains: "The blue colour of the early Universe is caused by the predominantly blue light from young stars in the galaxies. The redder colour of the Universe today is caused by the relatively larger number of older, redder stars." The team leader, Gregory Rudnick from the Max-Planck Institut fr Astrophysics (Garching, Germany) adds: "Since the total amount of light in the Universe in the past was about the same as today and a young blue star emits much more light than an old red star, there must have been significantly fewer stars in the young Universe than there is now. Our new findings imply that the majority of stars in the Universe were formed comparatively late, not so long before our Sun was born, at a moment when the Universe was around 7,000 million years old." These new results are based on unique data collected during more than 100 hours of observations with the ISAAC multi-mode instrument at ESO's Very Large Telescope (VLT), as part of a major research project, the Faint InfraRed Extragalactic Survey (FIRES) . The distances to the galaxies were estimated from their brightness in different optical near-infrared wavelength bands. PR Photo 34/03 : The Evolving Colour of the Universe . Observing the early Universe It is now well known that the Sun was formed some 4.5 billion years ago. But when did most of the other stars in our home Galaxy form? And what about stars in other galaxies? These are some of the key questions in present-day astronomy, but they can only be answered by means of observations with the world's largest telescopes. One way to address these issues is to observe the very young Universe directly - by looking back in time. For this, astronomers take advantage of the fact that light emitted by very distant galaxies travels a long time before reaching us. Thus, when astronomers look at such remote objects, they see them as they appeared long ago. Those remote galaxies are extremely faint, however, and these observations are therefore technically difficult. Another complication is that, due to the expansion of the Universe, light from those galaxies is shifted towards longer wavelengths [2], out of the optical wavelength range and into the infrared region. In order to study those early galaxies in some detail, astronomers must therefore use the largest ground-based telescopes, collecting their faint light during very long exposures. In addition they must use infrared-sensitive detectors. Telescopes as giant eyes The "Hubble Deep Field South (HDF-S)" is a very small portion of the sky in the southern constellation Tucanae ( "the Toucan" ). It was selected for very detailed studies with the Hubble Space Telescope (HST) and other powerful telescopes. Optical images of this field obtained by the HST represent a total exposure time of 140 hours. Many ground-based telescopes have also obtained images and spectra of objects in this sky area, in particular the ESO telescopes in Chile. A sky area of 2.5 x 2.5 arcmin 2 in the direction of HDF-S was observed in the context of a thorough study (the Faint InfraRed Extragalactic Survey; FIRES, see ESO PR 23/02 ). It is slightly larger than the field covered by the WFPC2 camera on the HST, but still 100 times smaller than the area subtended by the full moon. Whenever this field was visible from the ESO Paranal Observatory and the atmospheric conditions were optimal, ESO astronomers pointed the 8.2-m VLT ANTU telescope in this direction, taking near-infrared images with the ISAAC multi-mode instrument. Altogether, the field was observed for more than 100 hours and the resulting images (see ESO PR 23/02 ), are the deepest ground-based views in the near-infrared Js- and H-bands. The Ks-band image is the deepest ever obtained of any sky field in this spectral band, whether from the ground or from space. These unique data provide an exceptional view and have now allowed unprecedented studies of the galaxy population in the young Universe. Indeed, because of the exceptional seeing conditions at Paranal, the data obtained with the VLT have an excellent image sharpness (a "seeing" of 0.48 arcsec) and can be combined with the HST optical data with almost no loss of quality. A bluer colour ESO PR Photo 34/03 ESO PR Photo 34/03 [Preview - JPEG: 501 x 400 pix - 21k [Normal - JPEG: 1003 x 800 pix - 178k] [Full Res - JPEG: 1200 x 958 pix - 230k] Captions : PR Photo 34a/03 shows a set of three-colour images of intrinsically bright galaxies in the Hubble Deep Field South. The galaxies are arranged horizontally by the age of the Universe when the light left each object. For reference, the Universe is now 13.7 billion years old. The colours of the galaxies have had the effect of redshift removed [2]. That is, the colours indicate the amount of light which is emitted at a given rest-frame wavelength, as observed by someone at the same redshift as each galaxy. These colours provide information about the ages of stars in the galaxies, where redder colours indicate older stars. At the bottom is shown how the mean colour of bright galaxies changes as the Universe gets older. The reddening in colour with time is due to the increasing mean age of the stars, cf. the text. The astronomers were able to detect unambiguously about 300 galaxies on these images. For each of them, they measured the distance by determining the redshift [2]. This was done by means of a newly improved method that is based on the comparison of the brightness of each object in all the individual spectral bands with that of a set of nearby galaxies. In this way, galaxies were found in the field with redshifts as high as z = 3.2 , corresponding to distances around 11,500 million light-years. In other words, the astronomers were seeing the light of these very remote galaxies as they were when the Universe was only about 2.2 billion year old. The astronomers next determined the amount of light emitted by each galaxy in such a way that the effects of the redshift were "removed". That is, they measured the amount of light at different wavelengths (colours) as it would have been recorded by an observer near that galaxy. This, of course, only refers to the light from stars that are not heavily obscured by dust. Summing up the light emitted at different wavelengths by all galaxies at a given cosmic epoch, the astronomers could then also determine the average colour of the Universe (the "cosmic colour") at that epoch. Moreover, they were able to measure how that colour has changed, as the Universe became older. They conclude that the cosmic colour is getting redder with time . In particular, it was much bluer in the past; now, at the age of nearly 14,000 million years, the Universe has a kind of beige colour. When did stars form ? The change of the cosmic colour with time may be interesting in itself, but it is also an essential tool for determining how rapidly stars were assembled in the Universe. Indeed, while the star-formation in individual galaxies may have complicated histories, sometimes accelerating into true "star-bursts", the new observations - now based on many galaxies - show that the "average history" of star-formation in the Universe is much simpler. This is evident by the observed, smooth change of the cosmic colour as the Universe became older. Using the cosmic colour the astronomers were also able to determine how the mean age of relatively unobscured stars in the Universe changed with time. Since the Universe was much bluer in the past than it is now, they concluded that the Universe is not producing as many blue (high mass, short-lived) stars now as it was earlier, while at the same time the red (low mass, long-lived) stars from earlier generations of star formation are still present. Blue, massive stars die more quickly than red, low-mass stars, and therefore as the age of a group of stars increases, the blue short-lived stars die and the average colour of the group becomes redder. So did the Universe as a whole. This behaviour bears some resemblance with the ageing trend in modern Western countries where less babies are born than in the past and people live longer than in the past, with the total effect that the mean age of the population is rising. The astronomers determined how many stars had already formed when the Universe was only about 3,000 million years old. Young stars (of blue colour) emit more light than older (redder) stars. However, since there was just about as much light in the young Universe as there is today - although the galaxies are now much redder - this implies that there were fewer stars in the early Universe than today. The present study inidcates that there were ten times fewer stars at that early time than there is now. Finally, the astronomers found that roughly half of the stars in the observed galaxies have been formed after the time when the Universe was about half as old (7,000 million years after the Big Bang) as it is today (14,000 million years). Although this result was derived from a study of a very small sky field, and therefore may not be completely representative of the Universe as a whole, the present result has been shown to hold in other sky fields.

  3. Contact Lenses for Vision Correction

    MedlinePLUS

    ... Prevention News Ask an Eye M.D. Espaol Contact Lenses Contact Lenses for Vision Correction Proper Care ... to Know About Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd ...

  4. Object tracking with stereo vision

    NASA Technical Reports Server (NTRS)

    Huber, Eric

    1994-01-01

    A real-time active stereo vision system incorporating gaze control and task directed vision is described. Emphasis is placed on object tracking and object size and shape determination. Techniques include motion-centroid tracking, depth tracking, and contour tracking.

  5. Contact Lenses for Vision Correction

    MedlinePLUS

    ... Eye M.D. Español Eye Health / Glasses & Contacts Contact Lenses Sections Contact Lenses for Vision Correction Proper ... to Know About Contact Lenses Colored Contact Lenses Contact Lenses for Vision Correction Written by: Kierstan Boyd ...

  6. Vision: Essential Scaffolding

    ERIC Educational Resources Information Center

    Murphy, Joseph; Torre, Daniela

    2015-01-01

    Few concepts are more noted in the leadership effects research than vision. It is a cardinal element in the school improvement equation as well. Yet, it remains one of the least well-specified components of that algorithm. Based on a comprehensive review of the research on effective leadership and school improvement from 1995 to 2012, we bring

  7. VISION AND READING ABILITY.

    ERIC Educational Resources Information Center

    MANGRUM, CHARLES T.

    SIGNIFICANT RESEARCH ON THE PHYSIOLOGICAL AND FUNCTIONAL ASPECTS OF VISION AND READING DISABILITY IS SURVEYED. CONCLUSIONS BASED ON THE LITERATURE IN THE FIELD ARE DISCUSSED. A BIBLIOGRAPHY OF 70 REFERENCES AND A GLOSSARY OF TERMS ARE APPENDED. A TABLE SUMMARIZING REFRACTIVE ERRORS AND EYE DEFECTS CONTRIBUTING TO READING DISABILITY IS INCLUDED.

  8. Two Visions of America

    ERIC Educational Resources Information Center

    Capaldi, Nicholas

    2012-01-01

    Since the seventeenth century, there have been two narratives about modernity in general and America in particular. The author uses the term "narrative" to include (a) facts, (b) arguments, and most important, (c) a larger vision of how one sees the world and chooses to engage the world. The first and originalist narrative is the Lockean Liberty

  9. A shared vision.

    PubMed

    Hogan, Brigid

    2007-12-01

    One of today's most powerful technologies in biomedical research--the creation of mutant mice by gene targeting in embryonic stem (ES) cells--was finally celebrated in this year's Nobel Prize in Medicine. The history of how ES cells were first discovered and genetically manipulated highlights the importance of collaboration among scientists from different backgrounds with a shared vision. PMID:18061560

  10. MARR: active vision model

    NASA Astrophysics Data System (ADS)

    Podladchikova, Lubov N.; Gusakova, Valentina I.; Shaposhnikov, Dmitry G.; Faure, Alain; Golovan, Alexander V.; Shevtsova, Natalia A.

    1997-09-01

    Earlier, the biologically plausible active vision, model for multiresolutional attentional representation and recognition (MARR) has been developed. The model is based on the scanpath theory of Noton and Stark and provides invariant recognition of gray-level images. In the present paper, the algorithm of automatic image viewing trajectory formation in the MARR model, the results of psychophysical experiments, and possible applications of the model are considered. Algorithm of automatic image viewing trajectory formation is based on imitation of the scanpath formed by operator. Several propositions about possible mechanisms for a consecutive selection of fixation points in human visual perception inspired by computer simulation results and known psychophysical data have been tested and confirmed in our psychophysical experiments. In particular, we have found that gaze switch may be directed (1) to a peripheral part of the vision field which contains an edge oriented orthogonally to the edge in the point of fixation, and (2) to a peripheral part of the vision field containing crossing edges. Our experimental results have been used to optimize automatic algorithm of image viewing in the MARR model. The modified model demonstrates an ability to recognize complex real world images invariantly with respect to scale, shift, rotation, illumination conditions, and, in part, to point of view and can be used to solve some robot vision tasks.

  11. Synthetic Vision Workshop 2

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J. (Compiler)

    1999-01-01

    The second NASA sponsored Workshop on Synthetic/Enhanced Vision (S/EV) Display Systems was conducted January 27-29, 1998 at the NASA Langley Research Center. The purpose of this workshop was to provide a forum for interested parties to discuss topics in the Synthetic Vision (SV) element of the NASA Aviation Safety Program and to encourage those interested parties to participate in the development, prototyping, and implementation of S/EV systems that enhance aviation safety. The SV element addresses the potential safety benefits of synthetic/enhanced vision display systems for low-end general aviation aircraft, high-end general aviation aircraft (business jets), and commercial transports. Attendance at this workshop consisted of about 112 persons including representatives from industry, the FAA, and other government organizations (NOAA, NIMA, etc.). The workshop provided opportunities for interested individuals to give presentations on the state of the art in potentially applicable systems, as well as to discuss areas of research that might be considered for inclusion within the Synthetic Vision Element program to contribute to the reduction of the fatal aircraft accident rate. Panel discussions on topical areas such as databases, displays, certification issues, and sensors were conducted, with time allowed for audience participation.

  12. Visions of Mobile Learning

    ERIC Educational Resources Information Center

    T.H.E. Journal, 2011

    2011-01-01

    It is almost a foregone conclusion that the mobile device will become an indispensable tool for learning in the future. That's why "T.H.E. Journal" asked a number of educators to let their imaginations go wild and conjure up visions of the future of the device in the classroom. This paper presents the views of educators who conjure up the mobile

  13. Two Visions of America

    ERIC Educational Resources Information Center

    Capaldi, Nicholas

    2012-01-01

    Since the seventeenth century, there have been two narratives about modernity in general and America in particular. The author uses the term "narrative" to include (a) facts, (b) arguments, and most important, (c) a larger vision of how one sees the world and chooses to engage the world. The first and originalist narrative is the Lockean Liberty…

  14. Visions of Mobile Learning

    ERIC Educational Resources Information Center

    T.H.E. Journal, 2011

    2011-01-01

    It is almost a foregone conclusion that the mobile device will become an indispensable tool for learning in the future. That's why "T.H.E. Journal" asked a number of educators to let their imaginations go wild and conjure up visions of the future of the device in the classroom. This paper presents the views of educators who conjure up the mobile…

  15. Lighting For Color Vision

    NASA Astrophysics Data System (ADS)

    Worthey, James A.

    1988-02-01

    Some results concerning lighting for human color vision can be generalized to robot color vision. These results depend mainly on the spectral sensitivities of the color channels, and their interaction with the spectral power distribution of the light. In humans, the spectral sensitivities of the R and G receptors show a large overlap, while that of the B receptors overlaps little with the other two. A color vision model that proves useful for lighting work---and which also models many features of human vision---is one in which the "opponent color" signals are T = R - G, and D = B - R. That is, a "red minus green" signal comes from the receptors with greatest spectral overlap, while a "blue minus yellow" signal comes from the two with the least overlap. Using this model, we find that many common light sources attenuate red-green contrasts, relative to daylight, while special lights can enhance red-green contrast slightly. When lighting changes cannot be avoided, the eye has some ability to compensate for them. In most models of "color constancy," only the light's color guides the eye's adjustment, so a lighting-induced loss of color contrast is not counteracted. Also, no constancy mechanism can overcome metamerism---the effect of unseen spectral differences between objects. However, we can calculate the extent to which a particular lighting change will reveal metamerism. I am not necessarily arguing for opponent processing within robots, but only presenting results based on opponent calculations.

  16. Extremal problems for colourings of uniform hypergraphs

    NASA Astrophysics Data System (ADS)

    Shabanov, D. A.

    2007-12-01

    We study a classical problem (first posed by Erd?s) in the extremal theory of hypergraphs. According to Erd?s, a hypergraph possesses property B if its set of vertices admits a 2-colouring such that no edge of the hypergraph is monochromatic. The problem is to find the minimum m(n) of all m such that there is an n-uniform (each edge contains exactly n vertices) hypergraph with exactly m edges that does not possess property B. We consider more general problems (including the case of polychromatic colourings) and introduce a number of parametric properties of hypergraphs. We obtain estimates for analogues of m(n) for extremal problems on various classes of hypergraphs.

  17. [Systems analysis of colour music corrective effect].

    PubMed

    Gumeniuk, V A; Batova, N Ia; Mel'nikova, T S; Glazachev, O S; Golubeva, N K; Klimina, N V; Hubner, P

    1998-01-01

    In the context of P. K. Anokhin's theory of functional systems, the corrective effects of various combinations of medical therapeutical resonance music (MTRM) and dynamic colour exposure were analyzed. As compared to rehabilitative music programmes, MRTM was shown to have a more pronounced relaxing effect as manifested both in the optimization of emotion and in the activity of autonomic regulation of cardiovascular functions. On combined MRTM and dynamic colour flow exposures, the relaxing effect is most marked. In the examinees, the personality and situation anxieties diminish, mood improves, cardiovascular parameters become normal, the rate of metabolic processes and muscular rigidity reduce, the spectral power of alpha-rhythm increases, these occurring predominantly in the anterior region of the brain. The findings suggest the high efficiency of the chosen way of normalizing the functional status of man. PMID:9567714

  18. The colour of domestication and the designer chicken

    NASA Astrophysics Data System (ADS)

    Sheppy, Andrew

    2011-03-01

    Colour is an important feature of most living organisms. In the wild, colour has great significance affecting the survival and reproductive success of the species. The environmental constraints which lead to the specific colours of birds and animals are very strong and individuals of novel colours tend not to survive. Under domestication, mankind has transformed all the species involved which have thus been freed from environmental pressures to a large extent. Early colour variants were mostly selected for utility reasons or religious practices. In more recent centuries colour varieties have been created purely for ornament and pleasure, fashion playing a surprisingly large part in their development. A bewildering array of colours and patterns can now be found in all our commensal species, especially the Domestic Fowl ( Gallus gallus domesticus).

  19. Synaesthetic colours do not camouflage form in visual search

    PubMed Central

    Gheri, C; Chopping, S; Morgan, M.J

    2008-01-01

    One of the major issues in synaesthesia research is to identify the level of processing involved in the formation of the subjective colours experienced by synaesthetes: are they perceptual phenomena or are they due to memory and association learning? To address this question, we tested whether the colours reported by a group of grapheme-colour synaesthetes (previously studied in an functional magnetic resonance imaging experiment) influenced them in a visual search task. As well as using a condition where synaesthetic colours should have aided visual search, we introduced a condition where the colours experienced by synaesthetes would be expected to make them worse than controls. We found no evidence for differences between synaesthetes and normal controls, either when colours should have helped them or where they should have hindered. We conclude that the colours reported by our population of synaesthetes are not equivalent to perceptual signals, but arise at a cognitive level where they are unable to affect visual search. PMID:18182374

  20. The HS chromaticity diagram and the Lmn colour space

    NASA Astrophysics Data System (ADS)

    Dohnal, Miroslav

    2006-03-01

    In this paper a new HS chromaticity diagram for 10-degree observer with more linear colour distribution is presented. Both, the spectral locus and curve of purple colours generate unity circle -the HS diagram. By using the CIE lightness L as the third dimension, the Lrnn colour space is generated. This new colour space is embedded into cylinder radius of 100 (it stands for chroma) and height of 100 (it stands for lightness). If n is plotted against m the points in resulting Lmn-space are not uniquely related to chromaticity because their position depends on the value of L. The colours of all object-colour stimuli fall within this cylinder boundary. The spectrum locus of the monochromatic stimuli is generally well outside the boundary of object-colour stimuli.