WorldWideScience

Sample records for human colour vision

  1. Unconventional colour vision.

    Science.gov (United States)

    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.

  2. Colour, vision and ergonomics.

    Science.gov (United States)

    Pinheiro, Cristina; da Silva, Fernando Moreira

    2012-01-01

    This paper is based on a research project - Visual Communication and Inclusive Design-Colour, Legibility and Aged Vision, developed at the Faculty of Architecture of Lisbon. The research has the aim of determining specific design principles to be applied to visual communication design (printed) objects, in order to be easily read and perceived by all. This study target group was composed by a selection of socially active individuals, between 55 and 80 years, and we used cultural events posters as objects of study and observation. The main objective is to overlap the study of areas such as colour, vision, older people's colour vision, ergonomics, chromatic contrasts, typography and legibility. In the end we will produce a manual with guidelines and information to apply scientific knowledge into the communication design projectual practice. Within the normal aging process, visual functions gradually decline; the quality of vision worsens, colour vision and contrast sensitivity are also affected. As people's needs change along with age, design should help people and communities, and improve life quality in the present. Applying principles of visually accessible design and ergonomics, the printed design objects, (or interior spaces, urban environments, products, signage and all kinds of visually information) will be effective, easier on everyone's eyes not only for visually impaired people but also for all of us as we age.

  3. Multi-coloured stereograms unveil two binocular colour mechanisms in human vision.

    Science.gov (United States)

    Erkelens, Casper J; van Ee, Raymond

    2002-04-01

    Two different colours, one presented to one eye and the other presented to the other eye, often create the impression of a third colour. This percept is known as binocular colour mixture. Here we use coloured stereograms to study binocular colour appearance. Vivid pastel colours are induced in monocular, achromatic patches, if these are placed in stereograms whose left and right images differ in colour. The build-up of the colours is slow and takes tens of seconds or even minutes in certain individuals. The induced colours remain visible during monocular viewing of the patch and decay gradually. The same colours are induced irrespective of whether the patches are placed in fusible or rivalrous stereograms. We show that these colour effects cannot be induced by monocular colour mechanisms, either alone or in combination with binocular colour mixing. We suggest that the colours are induced by a binocular feedback mechanism, which reduces colour differences between the colour appearances of two monocular images. Induced colours are not observed if the achromatic patches are binocular. However, induced colours are apparent if one switches to monocular viewing after prolonged binocular viewing of the binocular patches. This aftereffect suggests that binocular colour induction acts on the monocular representations of binocular images. We suggest that during binocular viewing the fast process of binocular colour mixing masks the changes in colour appearance produced by the much slower process of binocular colour induction.

  4. Spotting Fruit versus Picking Fruit as the Selective Advantage of Human Colour Vision

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    Aline Bompas

    2013-04-01

    Full Text Available The spatiochromatic properties of the red–green dimension of human colour vision appear to be optimized for picking fruit in leaves at about arms' reach. However, other evidence suggests that the task of spotting fruit from a distance might be more important. This discrepancy may arise because the task a system (e.g. human trichromacy is best at is not necessarily the same task where the largest advantage occurs over the evolutionary alternatives (dichromacy or anomalous trichromacy. We tested human dichromats, anomalous trichromats and “normal” trichromats in a naturalistic visual search task in which they had to find fruit pieces in a bush at 1, 4, 8 or 12 m viewing distance. We found that the largest advantage (in terms of either performance ratio or performance difference of normal trichromacy over both types of colour deficiency was for the largest viewing distance. We infer that in the evolution of human colour vision, spotting fruit from a distance was a more important selective advantage than picking fruit at arms' reach.

  5. Evolution of colour vision in mammals.

    Science.gov (United States)

    Jacobs, Gerald H

    2009-10-12

    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.

  6. Evolution of colour vision in mammals

    OpenAIRE

    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...

  7. Colour Vision Deficiency and Physics Teaching

    Science.gov (United States)

    Maule, Louise; Featonby, David

    2016-01-01

    1 in 12 males suffer from some form of colour vision deficiency (CVD) which in the present colour dominated world of education presentation can be a severe disadvantage. Although aware of "colourblindness" most teachers make little or no adjustment for these pupils for whom tasks may be more difficult. This article examines colour vision…

  8. Colour vision deficiency and physics teaching

    Science.gov (United States)

    Maule, Louise; Featonby, David

    2016-05-01

    1 in 12 males suffer from some form of colour vision deficiency (CVD) which in the present colour dominated world of education presentation can be a severe disadvantage. Although aware of ‘colourblindness’ most teachers make little or no adjustment for these pupils for whom tasks may be more difficult. This article examines colour vision deficiency and looks at ways in which we can help the many students who have this problem.

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

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    Lina S V Roth

    Full Text Available 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.

  10. Occupational colour vision requirements for police officers.

    Science.gov (United States)

    Birch, Jennifer; Chisholm, Catharine M

    2008-11-01

    Inclusion of public service professions in the UK Disability Discrimination Act in 2004 prompted a review of occupational colour vision requirements for police officers. Changes in the regulations which existed prior to 2003 were proposed. The aim of this study was to obtain the views of serving police officers in Northern Ireland on the importance of good colour discrimination in everyday police work and on the recruitment regulations for patrol constables introduced in 2003 in mainland UK. These views were obtained by means of a questionnaire and informal discussions. More than 65% of police officers who responded to the questionnaire considered that good colour vision was very important for effective policing. Fewer than 2% considered that colour vision was unimportant. Experienced police officers agreed that the employment of colour-deficient patrol constables, as permitted in the new regulations, would lead to reduced efficiency and organisational difficulties at the local level. A number of everyday activities were described which showed the need for accurate colour discrimination. The change in recruitment policy and the lack of clarity in the new regulations show inadequate appreciation of the needs of the occupation, of different types of colour vision anomalies and of the diagnostic function of colour vision tests. Failure to provide guidance on appropriate colour vision tests, examination procedures and counselling services is likely to result in inconsistent employment policies in different police forces. It is recommended that the colour vision standard in place prior to 2003 is reinstated at the recruitment stage. The Ishihara test should be used for screening, and colour-deficient applicants further examined with the Farnsworth D15 test as a replacement for the City University Test 2nd edition.

  11. A STANDARDIZED LANTERN FOR TESTING COLOUR VISION.

    Science.gov (United States)

    Martin, L C

    1939-01-01

    A Lantern for lesting Colour-Vision is arranged to show test colours in pairs as in the Board of Trade Lantern. It is adapted to use electric light, and is standardized by stringent testing. The paper discusses the experiments and considerations which led to the formulation of the allowable tolerances in the transmission and colour co-ordinate specifications of the filters, the colour temperature of the lamps and so on. The results of tests on normal and colour-defective subjects are described.

  12. Colour Vision Impairment in Young Alcohol Consumers.

    Directory of Open Access Journals (Sweden)

    Alódia Brasil

    Full Text Available 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

  13. Colour Vision Impairment in Young Alcohol Consumers

    Science.gov (United States)

    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

  14. Colour Vision Impairment in Young Alcohol Consumers.

    Science.gov (United States)

    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.

  15. Colour-grapheme synaesthesia affects binocular vision

    Directory of Open Access Journals (Sweden)

    Chris L.E. Paffen

    2011-11-01

    Full Text Available In colour-grapheme synaesthesia, non-coloured graphemes are perceived as being inherently coloured. In recent years, it has become evident that synaesthesia-inducing graphemes can affect visual processing in a manner comparable to real, physical colours. Here, we exploit the phenomenon of binocular rivalry in which incompatible images presented dichoptically compete for conscious expression. Importantly, the competition only arises if the two images are sufficiently different; if the difference between the images is small, the images will fuse into a single mixed percept. We show that achromatic graphemes that induce synaesthetic colour percepts evoke binocular rivalry, while without the synaesthetic percept, they do not. That is, compared to achromatically perceived graphemes, synaesthesia-inducing graphemes increase the predominance of binocular rivalry over binocular fusion. This finding shows that the synaesthetic colour experience can provide the conditions for evoking binocular rivalry, much like stimulus features that induce rivalry in normal vision.

  16. Coevolution of coloration and colour vision?

    Science.gov (United States)

    Lind, Olle; Henze, Miriam J; Kelber, Almut; Osorio, Daniel

    2017-07-05

    The evolutionary relationship between signals and animal senses has broad significance, with potential consequences for speciation, and for the efficacy and honesty of biological communication. Here we outline current understanding of the diversity of colour vision in two contrasting groups: the phylogenetically conservative birds, and the more variable butterflies. Evidence for coevolution of colour signals and vision exists in both groups, but is limited to observations of phenotypic differences between visual systems, which might be correlated with coloration. Here, to illustrate how one might interpret the evolutionary significance of such differences, we used colour vision modelling based on an avian eye to evaluate the effects of variation in three key characters: photoreceptor spectral sensitivity, oil droplet pigmentation and the proportions of different photoreceptor types. The models predict that physiologically realistic changes in any one character will have little effect, but complementary shifts in all three can substantially affect discriminability of three types of natural spectra. These observations about the adaptive landscape of colour vision may help to explain the general conservatism of photoreceptor spectral sensitivities in birds. This approach can be extended to other types of eye and spectra to inform future work on coevolution of coloration and colour vision.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

  17. Colour-grapheme synesthesia affects binocular vision.

    Science.gov (United States)

    Paffen, Chris L E; van der Smagt, Maarten J; Nijboer, Tanja C W

    2011-01-01

    In colour-grapheme synesthesia, non-coloured graphemes are perceived as being inherently coloured. In recent years, it is debated whether visual processing of synesthesia-inducing achromatic graphemes is similar to that of chromatic graphemes. Here, we exploit the phenomenon of binocular rivalry in which incompatible images presented dichoptically compete for conscious expression. Importantly, the competition only arises if the two images are sufficiently different; if the difference between the images is small, the images will fuse into a single mixed percept. We show that achromatic digits that induce synesthetic colour percepts increase the incidence of binocular rivalry compared to achromatic non-digits that do not evoke such percepts. That is, compared to achromatically perceived non-digits, synesthesia-inducing digits increase the predominance of binocular rivalry over binocular fusion. This finding shows that the synesthetic colour experience can provide the conditions for promoting binocular rivalry, much like stimulus features that induce rivalry in normal vision.

  18. Correlation between dichromatic colour vision and jumping performance in horses.

    Science.gov (United States)

    Spaas, Julie; Helsen, Werner F; Adriaenssens, Maurits; Broeckx, Sarah; Duchateau, Luc; Spaas, Jan H

    2014-10-01

    There is general agreement that horses have dichromatic colour vision with similar capabilities to human beings with red-green colour deficiencies. However, whether colour perception has an impact on equine jumping performance and how pronounced the colour stimulus might be for a horse is unknown. The present study investigated the relationship between the colour of the fences (blue or green) and the show jumping performance of 20 horses ridden by two riders using an indoor and outdoor set of green and blue fences. In the indoor arena, significantly more touches and faults were made on blue fences in comparison to green fences (median difference of 2.5 bars). When only touched bars were included, a significant median difference of one bar was found. Mares (n = 4) demonstrated more faults and had a significantly greater difference in touches and faults between the two colours than male horses (n = 16). Repeating the same experiment with eight horses in an outdoor grass arena revealed no significant differences between the two colours. In order to draw any definite conclusions, more research concerning the colour perception, influence of contrast with the arena surface and sex of horse is required.

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

    Science.gov (United States)

    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. © 2015. Published by The Company of Biologists Ltd.

  20. Modelling colour constancy in fish: implications for vision and signalling in water.

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    Wilkins, Lucas; Marshall, N Justin; Johnsen, Sönke; Osorio, D

    2016-06-15

    Colour vision and colour signals are important to aquatic animals, but light scattering and absorption by water distorts spectral stimuli. To investigate the performance of colour vision in water, and to suggest how photoreceptor spectral sensitivities and body colours might evolve for visual communication, we model the effects of changes in viewing distance and depth on the appearance of fish colours for three teleosts: a barracuda, Sphyraena helleri, which is dichromatic and two damselfishes, Chromis verater and Chromis hanui, which are trichromatic. We assume that photoreceptors light-adapt to the background, thereby implementing the von Kries transformation, which can largely account for observed colour constancy in humans and other animals, including fish. This transformation does not, however, compensate for light scattering over variable viewing distances, which in less than a metre seriously impairs dichromatic colour vision, and makes judgement of colour saturation unreliable for trichromats. The von Kries transformation does substantially offset colour shifts caused by changing depth, so that from depths of 0 to 30 m modelled colour changes (i.e. failures of colour constancy) are sometimes negligible. However, the magnitudes and directions of remaining changes are complex, depending upon the specific spectral sensitivities of the receptors and the reflectance spectra. This predicts that when judgement of colour is important, the spectra of signalling colours and photoreceptor spectral sensitivities should be evolutionarily linked, with the colours dependent on photoreceptor spectral sensitivities, and vice versa.

  1. Defects of colour vision: A review of congenital and acquired colour vision deficiencies

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    Nabeela Hasrod

    2016-03-01

    Full Text Available Colour vision deficiencies (CVDs can be categorised as being congenital or acquired. Some CVDs are already present at birth, as inherited conditions that are the result of changes at the photo-pigment level and are non-pathological, incurable and do not change over time. Examples are red-green defects which are inherited as an X-linked recessive trait. Acquired CVD develops secondary to ocular and systemic conditions or as a side effect of certain medications or sometimes toxic effects of chemicals, and trauma and ageing can also be important in some CVDs.

  2. Sensory adaptation. Tunable colour vision in a mantis shrimp.

    Science.gov (United States)

    Cronin, T W; Caldwell, R L; Marshall, J

    2001-05-31

    Systems of colour vision are normally identical in all members of a species, but a single design may not be adequate for species living in a diverse range of light environments. Here we show that in the mantis shrimp Haptosquilla trispinosa, which occupies a range of depths in the ocean, long-wavelength colour receptors are individually tuned to the local light environment. The spectral sensitivity of specific classes of photoreceptor is adjusted by filters that vary between individuals.

  3. Dichromatic colour vision in an Australian marsupial, the tammar wallaby.

    Science.gov (United States)

    Hemmi, J M

    1999-12-01

    Despite earlier assertions that most mammals are colour blind, colour vision has in recent years been demonstrated in a variety of eutherian mammals from a wide range of different orders. This paper presents the first behavioural evidence from colour discrimination experiments, that an Australian marsupial, the tammar wallaby (Macropus eugenii), has dichromatic colour vision. In addition, the experiments show that the wallabies readily learn the relationship between the presented colours rather than the absolute hues. This provides a sensitive method to measure the location of the neutral-point, which is the wavelength of monochromatic light that is indistinguishable from white. This point is a diagnostic feature for dichromats. The spectral sensitivity of the wallabies' middle-wavelength-sensitive photoreceptor is known (peak: 539 nm) and the behavioural results imply that the sensitivity of the short-wavelength-sensitive receptor must be near 420 nm. These spectral sensitivities are similar to those found in eutherian mammals, supporting the view that the earliest mammals had dichromatic colour vision.

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

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    Gomez, Doris; Grégoire, 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.

  5. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test

    National Research Council Canada - National Science Library

    Dain, Stephen J; AlMerdef, Ali

    2016-01-01

    ...) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation...

  6. Inherited colour vision deficiencies: From Dalton to molecular genetics

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    Cvetković Dragana

    2005-01-01

    Full Text Available 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.

  7. Ultraviolet sensitivity and colour vision in raptor foraging.

    Science.gov (United States)

    Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut

    2013-05-15

    Raptors have excellent vision, yet it is unclear how they use colour information. It has been suggested that raptors use ultraviolet (UV) reflections from vole urine to find good hunting grounds. In contrast, UV plumage colours in songbirds such as blue tits are assumed to be 'hidden' communication signals, inconspicuous to raptors. This ambiguity results from a lack of knowledge about raptor ocular media transmittance, which sets the limit for UV sensitivity. We measured ocular media transmittance in common buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), red kites (Milvus milvus) and kestrels (Falco tinnunculus) so that, for the first time, raptor UV sensitivity can be fully described. With this information, and new measurements of vole urine reflectance, we show that (i) vole urine is unlikely to provide a reliable visual signal to hunting raptors and (ii) blue tit plumage colours are more contrasting to blue tits than to sparrowhawks because of UV reflectance. However, as the difference between blue tit and sparrowhawk vision is subtle, we suggest that behavioural data are needed to fully resolve this issue. UV cues are of little or no importance to raptors in both vole and songbird interactions and the role of colour vision in raptor foraging remains unclear.

  8. Uniformity of colour vision in Old World monkeys.

    OpenAIRE

    Jacobs, G.H.; Deegan, J F

    1999-01-01

    It is often assumed that all Old World monkeys share the same trichromatic colour vision, but the evidence in support of this conclusion is sparse as only a small fraction of all Old World monkey species have been tested. To address this issue, spectral sensitivity functions were measured in animals from eight species of Old World monkey (five cercopithecine species and three colobine species) using a non-invasive electrophysiological technique. Each of the 25 animals examined had spectrally ...

  9. Artificial human vision.

    Science.gov (United States)

    Dowling, Jason

    2005-01-01

    Can vision be restored to the blind? As early as 1929 it was discovered that stimulating the visual cortex of an individual led to the perception of spots of light, known as phosphenes [1] . The aim of artificial human vision systems is to attempt to utilize the perception of phosphenes to provide a useful substitute for normal vision. Currently, four locations for electrical stimulation are being investigated; behind the retina (subretinal), in front of the retina (epiretinal), the optic nerve and the visual cortex (using intra- and surface electrodes). This review discusses artificial human vision technology and requirements, and reviews the current development projects.

  10. Looking for the dichromatic version of a colour vision model

    Science.gov (United States)

    Capilla, P.; Luque, M. J.; Díez-Ajenjo, M. A.

    2004-09-01

    Different hypotheses on the sensitivity of photoreceptors and post-receptoral mechanisms were introduced in different colour vision models to derive acceptable dichromatic versions. Models with one (Ingling and T'sou, Guth et al, Boynton) and two linear opponent stages (DeValois and DeValois) and with two non-linear opponent stages (ATD95) were used. The L- and M-cone sensitivities of red-green defectives were either set to zero (cone-loss hypothesis) or replaced by that of a different cone-type (cone-replacement hypothesis), whereas for tritanopes the S-cone sensitivity was always assumed to be zero. The opponent mechanisms were either left unchanged or nulled in one or in all the opponent stages. The dichromatic models obtained have been evaluated according to their performance in three tests: computation of the spectral sensitivity of the dichromatic perceptual mechanisms, prediction of the colour loci describing dichromatic appearance and prediction of the gamut of colours that dichromats perceive as normal subjects do.

  11. iPad colour vision apps for dyschromatopsia screening.

    Science.gov (United States)

    Campbell, Thomas Gordon; Lehn, Alexander; Blum, Stefan; Airey, Caroline; Brown, Helen

    2016-07-01

    Optic neuritis (ON) is a common and important cause of vision loss or vision disturbances in the community, particularly amongst the young, and it is often associated with a persistent dyschromatopsia. Traditionally screening for dyschromatopsia has been carried out using pseudo-isochromatic Ishihara plates. These colour plates were originally developed for testing of colour blindness, and indeed have only more recently been applied to ON. As the Ishihara plate books used for testing are expensive, unwieldy, and are not commonly available in many clinics or wards, many neurologists and ophthalmologists have taken to using untested and unstudied downloadable software packages on portable electronic devices for testing. This study compared the efficacy of printed and iPad (Apple, Cupertino, CA, USA) versions of the Ishihara plates in screening for dyschromatopsia in patients who were suspected of having ON. The main finding was that dyschromatopsia testing using a commercially available application on an iPad was comparable to using the current pragmatic clinical benchmark, the pseudo-isochromatic plates of Ishihara. These findings provide support for the increasingly common practice of screening for dyschromatopsia using the iPad.

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

    Science.gov (United States)

    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…

  13. Assessment of colour vision in epileptic patients exposed to single-drug therapy.

    Science.gov (United States)

    López, L; Thomson, A; Rabinowicz, A L

    1999-01-01

    Diplopia, blurred vision and colour disturbances are well-known side effects associated with anti-epileptic drugs (AEDs). Farnsworth-Munsell 100-hue colour test (F-100) is an accepted and sensitive tool to detect changes in colour perception. To determine the impact of AEDs upon colour vision, we evaluated 37 consecutive patients with complex partial seizures exposed to monotherapy with phenytoin (PHT, carbamazepine (CBZ) or valproic acid (VPA). All had normal IQ and no congenital disturbances in colour vision or ocular diseases. Twenty normal controls were used for statistical analysis. Thirteen patients were exposed to PHT, 12 to CBZ and 12 to VPA. Visual colour perception was impaired in 30/37 (82%) of the study group. The most significant abnormality was detected in the blue-yellow axis in 10/13 patients exposed to PHT (p < 0.02) and in 8/12 treated with CBZ (p < 0.009). In 8/12 patients taking VPA, no significant abnormality was observed (p < 0.06). None of the studied patients complained of colour vision disturbances. Our findings strongly support the negative effect of AEDs upon colour vision discrimination, most likely due to changes at the retinal processing level. F-100 proved to be very useful to assess early toxicity due to AEDs.

  14. Application of Computer Vision for quality control in frozen mixed berries production: colour calibration issues

    Directory of Open Access Journals (Sweden)

    D. Ricauda Aimonino

    2013-09-01

    Full Text Available Computer vision is becoming increasingly important in quality control of many food processes. The appearance properties of food products (colour, texture, shape and size are, in fact, correlated with organoleptic characteristics and/or the presence of defects. Quality control based on image processing eliminates the subjectivity of human visual inspection, allowing rapid and non-destructive analysis. However, most food matrices show a wide variability in appearance features, therefore robust and customized image elaboration algorithms have to be implemented for each specific product. For this reason, quality control by visual inspection is still rather diffused in several food processes. The case study inspiring this paper concerns the production of frozen mixed berries. Once frozen, different kinds of berries are mixed together, in different amounts, according to a recipe. The correct quantity of each kind of fruit, within a certain tolerance, has to be ensured by producers. Quality control relies on bringing few samples for each production lot (samples of the same weight and, manually, counting the amount of each species. This operation is tedious, subject to errors, and time consuming, while a computer vision system (CVS could determine the amount of each kind of berries in a few seconds. This paper discusses the problem of colour calibration of the CVS used for frozen berries mixture evaluation. Images are acquired by a digital camera coupled with a dome lighting system, which gives a homogeneous illumination on the entire visible surface of the berries, and a flat bed scanner. RBG device dependent data are then mapped onto CIELab colorimetric colour space using different transformation operators. The obtained results show that the proposed calibration procedure leads to colour discrepancies comparable or even below the human eyes sensibility.

  15. Is colour cognitive?

    Science.gov (United States)

    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.

  16. The "Human Colour" Crayon: Investigating the Attitudes and Perceptions of Learners Regarding Race and Skin Colour

    Science.gov (United States)

    Alexander, Neeske; Costandius, Elmarie

    2017-01-01

    Some coloured and black learners in South Africa use a light orange or pink crayon to represent themselves in art. Many learners name this colour "human colour" or "skin colour". This is troublesome, because it could reflect exclusionary ways of representing race in images and language. This case study, conducted with two…

  17. An example of applied colour vision research: the conspicuity of airplane colour

    NARCIS (Netherlands)

    Lucassen, M.P.

    2002-01-01

    This paper describes the application of the combined knowledge on colorimetry, colour imaging (visualization) and colour perception in an aviation related research project. It involves the optimisation of the conspicuity of the colour scheme of an airplane, with the purpose of minimizing the changes

  18. An example of applied colour vision research: the conspicuity of airplane colour

    NARCIS (Netherlands)

    Lucassen, M.P.

    2002-01-01

    This paper describes the application of the combined knowledge on colorimetry, colour imaging (visualization) and colour perception in an aviation related research project. It involves the optimisation of the conspicuity of the colour scheme of an airplane, with the purpose of minimizing the changes

  19. Detection of colour vision changes in patients with systemic diseases that can affect the eye

    National Research Council Canada - National Science Library

    KEUKEN, A; RODRIGUEZ‐CARMONA, M; BARBUR, JL

    2012-01-01

    Purpose Changes in colour vision can provide the earliest signs of vision loss caused by either retinal or systemic disease (Expert Rev.Ophthalmol. 6(4):409‐420,2011). Both yellow‐blue (YB) and red‐green (RG...

  20. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test.

    Science.gov (United States)

    Dain, Stephen J; AlMerdef, Ali

    2016-05-01

    Given the versatility of smart phone displays, it was inevitable that applications (apps) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation. The colours of the displays produced by the apps are assessed with reference to the colours of a printed Ishihara test. The visual task is assessed on the basis of the colour differences and the alignment to the dichromatic confusion lines. The apps vary in quality and while some are colorimetrically acceptable, there are also some problems with their construction in making them a clinically useful app rather than curiosity driven self-testing. There is no reason why, in principle, a suitable test cannot be designed for smart phones.

  1. Effect of colour vision status on insect prey capture efficiency of captive and wild tamarins (Saguinus spp.)

    OpenAIRE

    Smith, Andrew C.; Surridge, Alison K; Mark J. Prescott; Osorio, Daniel; Mundy, Nicholas I; Hannah M Buchanan-Smith

    2012-01-01

    The colour vision polymorphism of most New World primates is a model system to study the function of colour vision. Theories for the evolution of primate trichromacy focus on the efficient detection and selection of ripe fruits and young leaves amongst mature leaves, when trichromats are likely to be better than dichromats. We provide data on whether colour vision status affects insect capture in primates. Trichromatic tamarins (Saguinus spp.) catch more prey than dichromats, but dichromats c...

  2. Impaired colour vision in workers exposed to organic solvents: A systematic review.

    Science.gov (United States)

    Betancur-Sánchez, A M; Vásquez-Trespalacios, E M; Sardi-Correa, C

    2017-01-01

    To evaluate recent evidence concerning the relationship between the exposure to organic solvents and the impairment of colour vision. A bibliographic search was conducted for scientific papers published in the last 15 years, in the LILACS, PubMed, Science Direct, EBSCO, and Cochrane databases that included observational studies assessing the relationship between impairment in colour vision and exposure to organic solvents. Eleven studies were selected that were performed on an economically active population and used the Lanthony D-15 desaturated test (D-15d), measured the exposure to organic solvents, and included unexposed controls. It was found that there is a statistically significant relationship between the exposure to organic solvents and the presence of an impairment in colour vision. The results support the hypothesis that exposure to organic solvents could induce acquired dyschromatopsia. The evaluation of colour vision with the D-15d test is simple and sensitive for diagnosis. More studies need to be conducted on this subject in order to better understand the relationship between impaired colour vision and more severe side effects caused by this exposure. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. High complexity of aquatic irradiance may have driven the evolution of four-dimensional colour vision in shallow-water fish.

    Science.gov (United States)

    Sabbah, Shai; Troje, Nikolaus F; Gray, Suzanne M; Hawryshyn, Craig W

    2013-05-01

    Humans use three cone photoreceptor classes for colour vision, yet many birds, reptiles and shallow-water fish are tetrachromatic and use four cone classes. Screening pigments, which narrow the spectrum of photoreceptors in birds and diurnal reptiles, render visual systems with four cone classes more efficient. To date, however, the question of tetrachromacy in shallow-water fish that, like humans, lack screening pigments, is still unsolved. We raise the possibility that tetrachromacy in fish has evolved in response to higher spectral complexity of underwater light. We compared the dimensionality of colour vision in humans and fish by examining the spectral complexity of the colour signal reflected from objects into their eyes. We show that fish require four to six cone classes to reconstruct the colour signal of aquatic objects at the accuracy level achieved by humans viewing terrestrial objects. This is because environmental light, which alters the colour signals, is more complex and contains more spectral fluctuations underwater than on land. We further show that fish cones are better suited than human cones to detect these spectral fluctuations, suggesting that the capability of fish cones to detect high-frequency fluctuations in the colour signal confers an advantage. Taken together, we propose that tetrachromacy in fish has evolved to enhance the reconstruction of complex colour signals in shallow aquatic environments. Of course, shallow-water fish might possess fewer than four cone classes; however, this would come with the inevitable loss in accuracy of signal reconstruction.

  4. An automatic colour-based computer vision algorithm for tracking the position of piglets

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Jover, J. M.; Alcaniz-Raya, M.; Gomez, V.; Balasch, S.; Moreno, J. R.; Grau-Colomer, V.; Torres, A.

    2009-07-01

    Artificial vision is a powerful observation tool for research in the field of livestock production. So, based on the search and recognition of colour spots in images, a digital image processing system which permits the detection of the position of piglets in a farrowing pen, was developed. To this end, 24,000 images were captured over five takes (days), with a five-second interval between every other image. The nine piglets in a litter were marked on their backs and sides with different coloured spray paints each one, placed at a considerable distance on the RGB space. The programme requires the user to introduce the colour patterns to be found, and the output is an ASCII file with the positions (column X, lineY) for each of these marks within the image analysed. This information may be extremely useful for further applications in the study of animal behaviour and welfare parameters (huddling, activity, suckling, etc.). The software programme initially segments the image in the RGB colour space to separate the colour marks from the rest of the image, and then recognises the colour patterns, using another colour space [B/(R+G+B), (G-R), (B-G)] more suitable for this purpose. This additional colour space was obtained testing different colour combinations derived from R, G and B. The statistical evaluation of the programmes performance revealed an overall 72.5% in piglet detection, 89.1% of this total being correctly detected. (Author) 33 refs.

  5. Augmenting full colour-fused multi-band night vision imagery with synthetic imagery in real-time

    NARCIS (Netherlands)

    Toet, A.; Hogervorst, M.A.; Son, R. van; Dijk, J.

    2011-01-01

    We present the design and first field trial results of an all-day all-weather enhanced and synthetic-fused multi-band colour night vision surveillance and observation system. The system augments a fused and dynamic three-band natural-colour night vision image with synthetic 3D imagery in real-time.

  6. Kansei Colour Concepts to Improve Effective Colour Selection in Designing Human Computer Interfaces

    Directory of Open Access Journals (Sweden)

    Tharangie K G D

    2010-05-01

    Full Text Available Colours have a major impact on Human Computer Interaction. Although there is a very thin line between appropriate and inappropriate use of colours, if used properly, colours can be a powerful tool to improve the usefulness of a computer interface in a wide variety of areas. Many designers mostly consider the physical aspect of the colour and tend to forget that psychological aspect of colour exists. However the findings of this study confirm that the psychological aspect or the affective dimension of colour also plays an important role in colour Interface design towards user satisfaction. Using Kansei Engineering principles the study explores the affective variability of colours and how it can be manipulated to provide better design guidance and solutions. A group of twenty adults from Sri Lanka, age ranging from 30 to 40 took part in the study. Survey was conducted using a Kansei colour questionnaire in normal atmospheric conditions. The results reveal that the affective variability of colours plays an important role in human computer interaction as an influential factor in drawing the user towards or withdrawing from the Interface. Thereby improving or degrading the user satisfaction.

  7. Can clinical colour vision tests be used to predict the results of the Farnsworth lantern test?

    Science.gov (United States)

    Cole, B L; Maddocks, J D

    1998-11-01

    Clinicians usually do not have access to a lantern test when making an occupational assessment of the ability of a person with defective colour vision to recognise signal light colours: they must rely on the results of ordinary clinical tests. While all colour vision defectives fail the Holmes Wright Type B lantern test and most fail the Holmes Wright Type A lantern, 35% of colour vision defectives pass the Farnsworth lantern. Can clinical tests predict who will pass and fail the Farnsworth lantern? We find that a pass (less than two or more diametrical crossings) at the Farnsworth Panel D 15 Dichotomous test has a sensitivity of 0.67 and specificity of 0.94 in predicting a pass or fail at the Farnsworth lantern test: a Nagel range of > 10 has a sensitivity of 0.87 and a specificity of 0.57. We conclude that neither the D 15 nor the Nagel Anomaloscope matching range are satisfactory predictors of performance on the Farnsworth Lantern.

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

    Directory of Open Access Journals (Sweden)

    Wiebke Ebeling

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  10. Molecular logic behind the three-way stochastic choices that expand butterfly colour vision.

    Science.gov (United States)

    Perry, Michael; Kinoshita, Michiyo; Saldi, Giuseppe; Huo, Lucy; Arikawa, Kentaro; Desplan, Claude

    2016-07-06

    Butterflies rely extensively on colour vision to adapt to the natural world. Most species express a broad range of colour-sensitive Rhodopsin proteins in three types of ommatidia (unit eyes), which are distributed stochastically across the retina. The retinas of Drosophila melanogaster use just two main types, in which fate is controlled by the binary stochastic decision to express the transcription factor Spineless in R7 photoreceptors. We investigated how butterflies instead generate three stochastically distributed ommatidial types, resulting in a more diverse retinal mosaic that provides the basis for additional colour comparisons and an expanded range of colour vision. We show that the Japanese yellow swallowtail (Papilio xuthus, Papilionidae) and the painted lady (Vanessa cardui, Nymphalidae) butterflies have a second R7-like photoreceptor in each ommatidium. Independent stochastic expression of Spineless in each R7-like cell results in expression of a blue-sensitive (Spineless(ON)) or an ultraviolet (UV)-sensitive (Spineless(OFF)) Rhodopsin. In P. xuthus these choices of blue/blue, blue/UV or UV/UV sensitivity in the two R7 cells are coordinated with expression of additional Rhodopsin proteins in the remaining photoreceptors, and together define the three types of ommatidia. Knocking out spineless using CRISPR/Cas9 (refs 5, 6) leads to the loss of the blue-sensitive fate in R7-like cells and transforms retinas into homogeneous fields of UV/UV-type ommatidia, with corresponding changes in other coordinated features of ommatidial type. Hence, the three possible outcomes of Spineless expression define the three ommatidial types in butterflies. This developmental strategy allowed the deployment of an additional red-sensitive Rhodopsin in P. xuthus, allowing for the evolution of expanded colour vision with a greater variety of receptors. This surprisingly simple mechanism that makes use of two binary stochastic decisions coupled with local coordination may prove

  11. Highly polymorphic colour vision in a New World monkey with red facial skin, the bald uakari (Cacajao calvus).

    Science.gov (United States)

    Corso, Josmael; Bowler, Mark; Heymann, Eckhard W; Roos, Christian; Mundy, Nicholas I

    2016-04-13

    Colour vision is highly variable in New World monkeys (NWMs). Evidence for the adaptive basis of colour vision in this group has largely centred on environmental features such as foraging benefits for differently coloured foods or predator detection, whereas selection on colour vision for sociosexual communication is an alternative hypothesis that has received little attention. The colour vision of uakaris (Cacajao) is of particular interest because these monkeys have the most dramatic red facial skin of any primate, as well as a unique fission/fusion social system and a specialist diet of seeds. Here, we investigate colour vision in a wild population of the bald uakari,C. calvus, by genotyping the X-linked opsin locus. We document the presence of a polymorphic colour vision system with an unprecedented number of functional alleles (six), including a novel allele with a predicted maximum spectral sensitivity of 555 nm. This supports the presence of strong balancing selection on different alleles at this locus. We consider different hypotheses to explain this selection. One possibility is that trichromacy functions in sexual selection, enabling females to choose high-quality males on the basis of red facial coloration. In support of this, there is some evidence that health affects facial coloration in uakaris, as well as a high prevalence of blood-borne parasitism in wild uakari populations. Alternatively, the low proportion of heterozygous female trichromats in the population may indicate selection on different dichromatic phenotypes, which might be related to cryptic food coloration. We have uncovered unexpected diversity in the last major lineage of NWMs to be assayed for colour vision, which will provide an interesting system to dissect adaptation of polymorphic trichromacy. © 2016 The Author(s).

  12. Frame Rate and Human Vision

    Science.gov (United States)

    Watson, Andrew B.

    2012-01-01

    To enhance the quality of the theatre experience, the film industry is interested in achieving higher frame rates for capture and display. In this talk I will describe the basic spatio-temporal sensitivities of human vision, and how they respond to the time sequence of static images that is fundamental to cinematic presentation.

  13. Shades of red: bird-pollinated flowers target the specific colour discrimination abilities of avian vision.

    Science.gov (United States)

    Shrestha, Mani; Dyer, Adrian G; Boyd-Gerny, Skye; Wong, Bob B M; Burd, Martin

    2013-04-01

    Colour signals are a major cue in putative pollination syndromes. There is evidence that the reflectance spectra of many flowers target the distinctive visual discrimination abilities of hymenopteran insects, but far less is known about bird-pollinated flowers. Birds are hypothesized to exert different selective pressures on floral colour compared with hymenopterans because of differences in their visual systems. We measured the floral reflectance spectra of 206 Australian angiosperm species whose floral visitors are known from direct observation rather than inferred from floral characteristics. We quantified the match between these spectra and the hue discrimination abilities of hymenopteran and avian vision, and analysed these metrics in a phylogenetically informed comparison of flowers in different pollination groups. We show that bird-visited flowers and insect-visited flowers differ significantly from each other in the chromatic cues they provide, and that the differences are concentrated near wavelengths of optimal colour discrimination by whichever class of pollinator visits the flowers. Our results indicate that angiosperms have evolved the spectral signals most likely to reinforce their pollinators' floral constancy (the tendency of individual pollinators to visit flowers of the same species) in communities of similarly coloured floral competitors.

  14. Computer vision system approach in colour measurements of foods: Part II. validation of methodology with real foods

    Directory of Open Access Journals (Sweden)

    Fatih TARLAK

    2016-01-01

    Full Text Available Abstract The colour of food is one of the most important factors affecting consumers’ purchasing decision. Although there are many colour spaces, the most widely used colour space in the food industry is L*a*b* colour space. Conventionally, the colour of foods is analysed with a colorimeter that measures small and non-representative areas of the food and the measurements usually vary depending on the point where the measurement is taken. This leads to the development of alternative colour analysis techniques. In this work, a simple and alternative method to measure the colour of foods known as “computer vision system” is presented and justified. With the aid of the computer vision system, foods that are homogenous and uniform in colour and shape could be classified with regard to their colours in a fast, inexpensive and simple way. This system could also be used to distinguish the defectives from the non-defectives. Quality parameters of meat and dairy products could be monitored without any physical contact, which causes contamination during sampling.

  15. Human eye colour and HERC2, OCA2 and MATP

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Børsting, Claus; Sanchez, Juan J.

    2010-01-01

    Prediction of human eye colour by forensic genetic methods is of great value in certain crime investigations. Strong associations between blue/brown eye colour and the SNP loci rs1129038 and rs12913832 in the HERC2 gene were recently described. Weaker associations between eye colour and other...... value of typing either the HERC2 SNPs rs1129038 and/or rs12913832 that are in strong linkage disequilibrium was observed when eye colour was divided into two groups, (1) blue, grey and green (light) and (2) brown and hazel (dark). Sequence variations in rs11636232 and rs7170852 in HERC2, rs1800407...... in OCA2 and rs16891982 in MATP showed additional association with eye colours in addition to the effect of HERC2 rs1129038. Diplotype analysis of three sequence variations in HERC2 and one sequence variation in OCA2 showed the best discrimination between light and dark eye colours with a likelihood ratio...

  16. The "Human Colour" Crayon: Investigating the Attitudes and Perceptions of Learners regarding Race and Skin Colour

    Directory of Open Access Journals (Sweden)

    Neeske Alexander

    2017-07-01

    Full Text Available Some coloured and black learners in South Africa use a light orange or pink crayon to represent themselves in art. Many learners name this colourhuman colour” or “skin colour”. This is troublesome, because it could reflect exclusionary ways of representing race in images and language. This case study, conducted with two schools in the Western Cape, investigated Grade 3 learners’ attitudes and perceptions regarding race and skin colour through art processes and discussion. The aim was to promote critical engagement with race in Foundation Phase educational contexts. Suggestions include changing the language used to describe skin colour, just recognition and representation of races in educational resources and the promotion of critical citizenship education. This research indicates the need to create practical curriculum guidelines to discuss race issues in the South African classroom.

  17. The Evolution of the Multicoloured Face of Mandrills: Insights from the Perceptual Space of Colour Vision

    Science.gov (United States)

    Renoult, Julien P.; Schaefer, H. Martin; Sallé, Bettina; Charpentier, Marie J. E.

    2011-01-01

    Multicomponent signals consist of several traits that are perceived as a whole. Although many animals rely on multicomponent signals to communicate, the selective pressures shaping these signals are still poorly understood. Previous work has mainly investigated the evolution of multicomponent signals by studying each trait individually, which may not accurately reflect the selective pressures exerted by the holistic perception of signal receivers. Here, we study the design of the multicoloured face of an Old World primate, the mandrill (Mandrillus sphinx), in relation to two aspects of signalling that are expected to be selected by receivers: conspicuousness and information. Using reflectance data on the blue and red colours of the faces of 34 males and a new method of hue vectorisation in a perceptual space of colour vision, we show that the blue hue maximises contrasts to both the red hue and the foliage background colouration, thereby increasing the conspicuousness of the whole display. We further show that although blue saturation, red saturation and the contrast between blue and red colours are all correlated with dominance, dominance is most accurately indicated by the blue-red contrast. Taken together our results suggest that the evolution of blue and red facial colours in male mandrills are not independent and are likely driven by the holistic perception of conspecifics. In this view, we propose that the multicoloured face of mandrills acts as a multicomponent signal. Last, we show that information accuracy increases with the conspicuousness of the whole display, indicating that both aspects of signalling can evolve in concert. PMID:22216180

  18. Skin blood perfusion and oxygenation colour affect perceived human health.

    Directory of Open Access Journals (Sweden)

    Ian D Stephen

    Full Text Available Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice.

  19. Computer Vision Method in Human Motion Detection

    Institute of Scientific and Technical Information of China (English)

    FU Li; FANG Shuai; XU Xin-he

    2007-01-01

    Human motion detection based on computer vision is a frontier research topic and is causing an increasing attention in the field of computer vision research. The wavelet transform is used to sharpen the ambiguous edges in human motion image. The shadow's effect to the image processing is also removed. The edge extraction can be successfully realized.This is an effective method for the research of human motion analysis system.

  20. Hemifield dependence of responses to colour in human fusiform gyrus.

    Science.gov (United States)

    Gonzalez, Francisco; Relova, José Luis; Prieto, Angel; Peleteiro, Manuel; Romero, Maria C

    2006-08-01

    To investigate the hemifield dependence of visually evoked responses to colour in the human fusiform gyrus we recorded evoked potentials from subdural electrodes in a patient suffering from occipital epilepsy. The responses in the fusiform gyrus show a strong hemifield dependence and discriminate the onset from the offset of the stimulus. Additionally, we found responses to squares made of random dots, whereas no responses were found to squares with a homogeneous bright surface. Our findings further support the idea that the fusiform gyrus is related to colour and pattern perception. However, the hemifield dependence we found may indicate that further processing is required in order to combine information from both visual hemifields.

  1. Object categorization: computer and human vision perspectives

    National Research Council Canada - National Science Library

    Dickinson, Sven J

    2009-01-01

    .... The result of a series of four highly successful workshops on the topic, the book gathers many of the most distinguished researchers from both computer and human vision to reflect on their experience...

  2. Human Vision Pathology Diagnostics by Photogrammetrics Means

    Science.gov (United States)

    Murynin, A.; Knyaz, V.; Mateev, I.

    2014-06-01

    One of the reasons of such vision pathology as human stereoscopic vision capability dysfunction is an asymmetry of a human face. As a rule, such dysfunctions occur as early as in the babyhood, when diagnostic methods applied for adults are ineffective. Early diagnostics and prophylaxis could help in treatment of such pathology and face 3D modeling is one of the promising ways to solve this problem.

  3. Colour detection thresholds in faces and colour patches.

    Science.gov (United States)

    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.

  4. The impact of skin colour on human photobiological responses

    OpenAIRE

    Fajuyigbe, Damilola; Young, Antony R.

    2016-01-01

    Terrestrial solar ultraviolet radiation (UVR) exerts both beneficial and adverse effects on human skin. Epidemiological studies show a lower incidence of skin cancer in people with pigmented skins compared to fair skins. This is attributed to photoprotection by epidermal melanin, as is the poorer vitamin D status of those with darker skins. We summarize a wide range of photobiological responses across different skin colours including DNA damage and immunosuppression. Some studies show the gen...

  5. Bona fide colour: DNA prediction of human eye and hair colour from ancient and contemporary skeletal remains.

    Science.gov (United States)

    Draus-Barini, Jolanta; Walsh, Susan; Pośpiech, Ewelina; Kupiec, Tomasz; Głąb, Henryk; Branicki, Wojciech; Kayser, Manfred

    2013-01-14

    DNA analysis of ancient skeletal remains is invaluable in evolutionary biology for exploring the history of species, including humans. Contemporary human bones and teeth, however, are relevant in forensic DNA analyses that deal with the identification of perpetrators, missing persons, disaster victims or family relationships. They may also provide useful information towards unravelling controversies that surround famous historical individuals. Retrieving information about a deceased person's externally visible characteristics can be informative in both types of DNA analyses. Recently, we demonstrated that human eye and hair colour can be reliably predicted from DNA using the HIrisPlex system. Here we test the feasibility of the novel HIrisPlex system at establishing eye and hair colour of deceased individuals from skeletal remains of various post-mortem time ranges and storage conditions. Twenty-one teeth between 1 and approximately 800 years of age and 5 contemporary bones were subjected to DNA extraction using standard organic protocol followed by analysis using the HIrisPlex system. Twenty-three out of 26 bone DNA extracts yielded the full 24 SNP HIrisPlex profile, therefore successfully allowing model-based eye and hair colour prediction. HIrisPlex analysis of a tooth from the Polish general Władysław Sikorski (1881 to 1943) revealed blue eye colour and blond hair colour, which was positively verified from reliable documentation. The partial profiles collected in the remaining three cases (two contemporary samples and a 14th century sample) were sufficient for eye colour prediction. Overall, we demonstrate that the HIrisPlex system is suitable, sufficiently sensitive and robust to successfully predict eye and hair colour from ancient and contemporary skeletal remains. Our findings, therefore, highlight the HIrisPlex system as a promising tool in future routine forensic casework involving skeletal remains, including ancient DNA studies, for the prediction of

  6. Genetic analyses of the human eye colours using a novel objective method for eye colour classification

    DEFF Research Database (Denmark)

    Andersen, Jeppe D.; Johansen, Peter; Harder, Stine

    2013-01-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically ...

  7. Genetic analyses of the human eye colours using a novel objective method for eye colour classification

    DEFF Research Database (Denmark)

    Andersen, Jeppe D.; Johansen, Peter; Harder, Stine;

    2013-01-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically...... and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had...... by different studies and to perform large meta-studies that may reveal loci with small effects on the eye colour....

  8. Color vision impairment in type 2 diabetes assessed by the D-15d test and the Cambridge Colour Test.

    Science.gov (United States)

    Feitosa-Santana, Claudia; Paramei, Galina V; Nishi, Mauro; Gualtieri, Mirella; Costa, Marcelo F; Ventura, Dora F

    2010-09-01

    Color vision impairment emerges at early stages of diabetes mellitus type 2 (DM2) and may precede diabetic retinopathy or the appearance of vascular alterations in the retina. The aim of the present study was to compare the evaluation of the color vision with two different tests - the Lanthony desaturated D-15d test (a traditional color arrangement test), and the Cambridge Colour Test (CCT) (a computerized color discrimination test) - in patients diagnosed with DM2 without clinical signs of diabetic retinopathy (DR), and in sex- and age-matched control groups. Both color tests revealed statistically significant differences between the controls and the worst eyes of the DM2 patients. In addition, the degree of color vision impairment diagnosed by both tests correlated with the disease duration. The D-15d outcomes indicated solely tritan losses. In comparison, CCT outcomes revealed diffuse losses in color discrimination: 13.3% for best eyes and 29% for worst eyes. In addition, elevation of tritan thresholds in the DM2 patients, as detected by the Trivector subtest of the CCT, was found to correlate with the level of glycated hemoglobin. Outcomes of both tests confirm that subclinical losses of color vision are present in DM2 patients at an early stage of the disease, prior to signs of retinopathy. Considering the advantages of the CCT test compared to the D-15d test, further studies should attempt to verify and/or improve the efficiency of the CCT test.

  9. Towards Understanding the Role of Colour Information in Scene Perception using Night Vision Device

    Science.gov (United States)

    2009-06-01

    sensitivity in more peripheral vision (Mullen and Kingdom, 1996), although this explanation has recently been challenged ( Martin et al., 2001). As...127, 398-45. 23. Hughes, P.K. (2001). What is different about vision through night vision goggles? In G. Kearney, M. Creamer , R. Marshall & A...scales for image data. IEEE Computer Graphics and Applications, 12, 72-80. 30. Martin , P., Lee, B.B., White, A.J.R., Solomon, S.G., & Rüttiger, L

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

    Science.gov (United States)

    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.

  11. Transforming 3D Coloured Pixels into Musical Instrument Notes for Vision Substitution Applications

    Directory of Open Access Journals (Sweden)

    Guido Bologna

    2007-08-01

    Full Text Available The goal of the See ColOr project is to achieve a noninvasive mobility aid for blind users that will use the auditory pathway to represent in real-time frontal image scenes. We present and discuss here two image processing methods that were experimented in this work: image simplification by means of segmentation, and guiding the focus of attention through the computation of visual saliency. A mean shift segmentation technique gave the best results, but for real-time constraints we simply implemented an image quantification method based on the HSL colour system. More particularly, we have developed two prototypes which transform HSL coloured pixels into spatialised classical instrument sounds lasting for 300 ms. Hue is sonified by the timbre of a musical instrument, saturation is one of four possible notes, and luminosity is represented by bass when luminosity is rather dark and singing voice when it is relatively bright. The first prototype is devoted to static images on the computer screen, while the second has been built up on a stereoscopic camera which estimates depth by triangulation. In the audio encoding, distance to objects was quantified into four duration levels. Six participants with their eyes covered by a dark tissue were trained to associate colours with musical instruments and then asked to determine on several pictures, objects with specific shapes and colours. In order to simplify the protocol of experiments, we used a tactile tablet, which took the place of the camera. Overall, colour was helpful for the interpretation of image scenes. Moreover, preliminary results with the second prototype consisting in the recognition of coloured balloons were very encouraging. Image processing techniques such as saliency could accelerate in the future the interpretation of sonified image scenes.

  12. Transforming 3D Coloured Pixels into Musical Instrument Notes for Vision Substitution Applications

    Directory of Open Access Journals (Sweden)

    Deville Benoît

    2007-01-01

    Full Text Available The goal of the See ColOr project is to achieve a noninvasive mobility aid for blind users that will use the auditory pathway to represent in real-time frontal image scenes. We present and discuss here two image processing methods that were experimented in this work: image simplification by means of segmentation, and guiding the focus of attention through the computation of visual saliency. A mean shift segmentation technique gave the best results, but for real-time constraints we simply implemented an image quantification method based on the HSL colour system. More particularly, we have developed two prototypes which transform HSL coloured pixels into spatialised classical instrument sounds lasting for 300 ms. Hue is sonified by the timbre of a musical instrument, saturation is one of four possible notes, and luminosity is represented by bass when luminosity is rather dark and singing voice when it is relatively bright. The first prototype is devoted to static images on the computer screen, while the second has been built up on a stereoscopic camera which estimates depth by triangulation. In the audio encoding, distance to objects was quantified into four duration levels. Six participants with their eyes covered by a dark tissue were trained to associate colours with musical instruments and then asked to determine on several pictures, objects with specific shapes and colours. In order to simplify the protocol of experiments, we used a tactile tablet, which took the place of the camera. Overall, colour was helpful for the interpretation of image scenes. Moreover, preliminary results with the second prototype consisting in the recognition of coloured balloons were very encouraging. Image processing techniques such as saliency could accelerate in the future the interpretation of sonified image scenes.

  13. Genetic analyses of the human eye colours using a novel objective method for eye colour classification

    DEFF Research Database (Denmark)

    Andersen, Jeppe D.; Johansen, Peter; Harder, Stine

    2013-01-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically......-score ranged from −1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE...... identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE...

  14. Neuropsychology of colour vision: Studies in patients with acquired brain damage, healthy participants, and cases

    NARCIS (Netherlands)

    Nijboer, T.C.W.

    2007-01-01

    In this thesis, we studied the neuropsychology of low-level sensory and higher-order visual perception in healthy participants, patients with acquired deficits in visual perception, and a man with a selective developmental deficit in colour processing. In neuropsychological literature, sensory

  15. Neuropsychology of colour vision: Studies in patients with acquired brain damage, healthy participants, and cases

    NARCIS (Netherlands)

    Nijboer, T.C.W.

    2007-01-01

    In this thesis, we studied the neuropsychology of low-level sensory and higher-order visual perception in healthy participants, patients with acquired deficits in visual perception, and a man with a selective developmental deficit in colour processing. In neuropsychological literature, sensory diso

  16. Studies of human vision recognition: some improvements

    Science.gov (United States)

    Wu, Bo-Wen; Fang, Yi-Chin; Chang, Lin-Song

    2010-01-01

    This paper proposes a new method to improve human recognition by artificial intelligence, specifically of images without the interference of high frequencies. The human eye is the most delicate optical system. Notwithstanding the dramatic progression of its structure and functions through a long evolution, the capability of visual recognition is not yet close to perfection. This paper is a study, based on the limitations of recognition by the human eye, of image recognition through the application of artificial intelligence. Those aspects which have been explored focus on human eye modeling, including aberration analysis, creative models of the human eye, human vision recognition characteristics and various mathematical models for verification. By using images consisting of four black and white bands and modulation transfer function (MTF) curve evaluation recognition capability on all the studied models, the optimum model most compatible with the physiology of the human eye is found.

  17. Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin's Ellipses and the Farnsworth-Munsell 100-Hue Test.

    Science.gov (United States)

    Bento-Torres, Natáli Valim Oliver; Rodrigues, Anderson Raiol; Côrtes, Maria Izabel Tentes; Bonci, Daniela Maria de Oliveira; Ventura, Dora Fix; Silveira, Luiz Carlos de Lima

    2016-01-01

    We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse's long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u' = 0.225, v' = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies.

  18. Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin’s Ellipses and the Farnsworth-Munsell 100-Hue Test

    Science.gov (United States)

    Bento-Torres, Natáli Valim Oliver; Rodrigues, Anderson Raiol; Côrtes, Maria Izabel Tentes; Bonci, Daniela Maria de Oliveira; Ventura, Dora Fix

    2016-01-01

    We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse’s long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u’ = 0.225, v’ = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies. PMID:27101124

  19. The Vision of Human Spaceflight

    Science.gov (United States)

    Mendell, Wendell

    2005-01-01

    First, we live in a world where change is the norm, not the exception. The scientific revolution springing from quantum mechanics yielded new understanding of solid state physics leading to stunning advances in computation, communication, and transportation. Two World Wars and one Cold War introduced massive governmental investment in research and development. The unusual pragmatic and classless entrepreneurship of U.S. society promoted commercialization and innovative marketing of new technology. As a result, the 20th Century experienced a constantly accelerating culture of change. Those societies that accepted and embraced the new capabilities dominated commercially and militarily; those that did not fell behind. I remember when there was no color television, when there were no personal computers, when there was no email, when there was no World Wide Web, when there were no cell phones. Now many of us cannot live without these things. Change has become the measure of success. Our children anticipate the future and do not expect it to look like the past. Secondly, our elementary school students are fascinated by dinosaurs, ghosts, and space. Astronauts create excitement. None question that humans will be in space in their future. They see it every week, even every day, in stories on television. To be an astronaut is considered a legitimate ambition. They see space travel to be an adventure just as our grandparents saw exploring Africa or the polar regions to be an adventure into the unknown. Third, we live in a time when our understanding of the space environment makes us realize that the existence of our species is one large impact away from extinction. We understand that our population explosion is changing our home planet in fundamental ways and that wars over terrestrial resources may be less than two generations away. We feel more connected to our space neighborhood than ever before. Many nations of the world are looking outward toward our Moon in an

  20. An Urban Colour Space in the Context of Culture

    Directory of Open Access Journals (Sweden)

    Olga Zheleznyak

    2015-08-01

    Full Text Available A colour space is seen as an actual discourse when discussing problems of formation and inhabitation of the modern city environment. The key aspect of such understanding is an activity-cultural interpretation of the urban environment colouristics proposed by the author, which allows building of an integral sphere of colour existence. This model of working with colour includes basic components and structures a colour space, while matching up all the elements (basic paradigms that provide proper functioning and development of the colour space; mechanisms of formation of colour paradigms; processes of formation and transformation of cultural norms and stereotypes; the culture of colour as a holistic unit that penetrates the variety of colour space forms, as well as the reality of colour establishment in the framework of human culture; the urban colouristics as a material and virtual, artificial and natural, organized and spontaneously appearing colour reality together with professional and conventional visions of it, etc..

  1. Epistatic adaptive evolution of human color vision.

    Directory of Open Access Journals (Sweden)

    Shozo Yokoyama

    2014-12-01

    Full Text Available Establishing genotype-phenotype relationship is the key to understand the molecular mechanism of phenotypic adaptation. This initial step may be untangled by analyzing appropriate ancestral molecules, but it is a daunting task to recapitulate the evolution of non-additive (epistatic interactions of amino acids and function of a protein separately. To adapt to the ultraviolet (UV-free retinal environment, the short wavelength-sensitive (SWS1 visual pigment in human (human S1 switched from detecting UV to absorbing blue light during the last 90 million years. Mutagenesis experiments of the UV-sensitive pigment in the Boreoeutherian ancestor show that the blue-sensitivity was achieved by seven mutations. The experimental and quantum chemical analyses show that 4,008 of all 5,040 possible evolutionary trajectories are terminated prematurely by containing a dehydrated nonfunctional pigment. Phylogenetic analysis further suggests that human ancestors achieved the blue-sensitivity gradually and almost exclusively by epistasis. When the final stage of spectral tuning of human S1 was underway 45-30 million years ago, the middle and long wavelength-sensitive (MWS/LWS pigments appeared and so-called trichromatic color vision was established by interprotein epistasis. The adaptive evolution of human S1 differs dramatically from orthologous pigments with a major mutational effect used in achieving blue-sensitivity in a fish and several mammalian species and in regaining UV vision in birds. These observations imply that the mechanisms of epistatic interactions must be understood by studying various orthologues in different species that have adapted to various ecological and physiological environments.

  2. Epistatic Adaptive Evolution of Human Color Vision

    Science.gov (United States)

    Yokoyama, Shozo; Xing, Jinyi; Liu, Yang; Faggionato, Davide; Altun, Ahmet; Starmer, William T.

    2014-01-01

    Establishing genotype-phenotype relationship is the key to understand the molecular mechanism of phenotypic adaptation. This initial step may be untangled by analyzing appropriate ancestral molecules, but it is a daunting task to recapitulate the evolution of non-additive (epistatic) interactions of amino acids and function of a protein separately. To adapt to the ultraviolet (UV)-free retinal environment, the short wavelength-sensitive (SWS1) visual pigment in human (human S1) switched from detecting UV to absorbing blue light during the last 90 million years. Mutagenesis experiments of the UV-sensitive pigment in the Boreoeutherian ancestor show that the blue-sensitivity was achieved by seven mutations. The experimental and quantum chemical analyses show that 4,008 of all 5,040 possible evolutionary trajectories are terminated prematurely by containing a dehydrated nonfunctional pigment. Phylogenetic analysis further suggests that human ancestors achieved the blue-sensitivity gradually and almost exclusively by epistasis. When the final stage of spectral tuning of human S1 was underway 45–30 million years ago, the middle and long wavelength-sensitive (MWS/LWS) pigments appeared and so-called trichromatic color vision was established by interprotein epistasis. The adaptive evolution of human S1 differs dramatically from orthologous pigments with a major mutational effect used in achieving blue-sensitivity in a fish and several mammalian species and in regaining UV vision in birds. These observations imply that the mechanisms of epistatic interactions must be understood by studying various orthologues in different species that have adapted to various ecological and physiological environments. PMID:25522367

  3. Tagore’s Dark Vision of Humanity

    Directory of Open Access Journals (Sweden)

    Alok BHALLA

    2013-04-01

    Full Text Available Tagore struggled against his dark vision of humanity to assert that the earth was a place of hierophanies and human life had a divine purpose. He failed. He called, with skepticism, for peace, equality and the restoration of earth’s loveliness: “I know I am crying in the wilderness, when I raise my voice of warning…” In a war-haunted and hungry Europe and Asia, he was confronted by a strange, cruel, and obstinately tribal world with its “legacy of ruin.” Though he asserted till his death in 1940 that he could never “commit the grievous sin of losing faith in man,” he could not turn away from “the crumbling ruins of … civilization….”

  4. The colours of humanity: the evolution of pigmentation in the human lineage.

    Science.gov (United States)

    Jablonski, Nina G; Chaplin, George

    2017-07-05

    Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus Homo, and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling Homo and Homo sapiens, loss of melanin pigmentation occurred under natural selection as Homo sapiens dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of Homo sapiens dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour-associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic 'palette' for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

  5. Colour vision in ADHD: part 1--testing the retinal dopaminergic hypothesis.

    Science.gov (United States)

    Kim, Soyeon; Al-Haj, Mohamed; Chen, Samantha; Fuller, Stuart; Jain, Umesh; Carrasco, Marisa; Tannock, Rosemary

    2014-10-24

    To test the retinal dopaminergic hypothesis, which posits deficient blue color perception in ADHD, resulting from hypofunctioning CNS and retinal dopamine, to which blue cones are exquisitely sensitive. Also, purported sex differences in red color perception were explored. 30 young adults diagnosed with ADHD and 30 healthy young adults, matched on age and gender, performed a psychophysical task to measure blue and red color saturation and contrast discrimination ability. Visual function measures, such as the Visual Activities Questionnaire (VAQ) and Farnsworth-Munsell 100 hue test (FMT), were also administered. Females with ADHD were less accurate in discriminating blue and red color saturation relative to controls but did not differ in contrast sensitivity. Female control participants were better at discriminating red saturation than males, but no sex difference was present within the ADHD group. Poorer discrimination of red as well as blue color saturation in the female ADHD group may be partly attributable to a hypo-dopaminergic state in the retina, given that color perception (blue-yellow and red-green) is based on input from S-cones (short wavelength cone system) early in the visual pathway. The origin of female superiority in red perception may be rooted in sex-specific functional specialization in hunter-gather societies. The absence of this sexual dimorphism for red colour perception in ADHD females warrants further investigation.

  6. Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

    Science.gov (United States)

    Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D; Hurlbert, Anya

    2014-01-01

    The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

  7. Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

    Directory of Open Access Journals (Sweden)

    Bradley Pearce

    Full Text Available The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K, all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

  8. Colorimetry and prime colours--a theorem.

    Science.gov (United States)

    Hornaes, Hans Petter; Wold, Jan Henrik; Farup, Ivar

    2005-08-01

    Human colour vision is the result of a complex process involving topics ranging from physics of light to perception. Whereas the diversity of light entering the eye in principle span an infinite-dimensional vector space in terms of the spectral power distributions, the space of human colour perceptions is three dimensional. One important consequence of this is that a variety of colours can be visually matched by a mixture of only three adequately chosen reference lights. It has been observed that there exists one particular set of monochromatic reference lights that, according to a certain definition, is optimal for producing colour matches. These reference lights are commonly denoted prime colours. In the present paper, we intend to rigorously show that the existence of prime colours is not particular to the human visual system as sometimes stated, but rather an algebraic consequence of the manner in which a kind of colorimetric functions called colour-matching functions are defined and transformed. The solution is based on maximisation of a determinant determining the gamut size of the colour space spanned by the prime colours. Cramer's rule for solving a set of linear equations is an essential part of the proof. By means of examples, it is shown that mathematically the optimal set of reference lights is not unique in general, and that the existence of a maximum determinant is not a necessary condition for the existence of prime colours.

  9. Colour Model for Outdoor Machine Vision for Tropical Regions and its Comparison with the CIE Model

    Energy Technology Data Exchange (ETDEWEB)

    Sahragard, Nasrolah; Ramli, Abdul Rahman B [Institute of Advanced Technology, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Marhaban, Mohammad Hamiruce [Department of Electrical and Electronic Engineering, Faculty of Engineering, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia); Mansor, Shattri B, E-mail: sahragard@yahoo.com [Department of Civil Engineering, Faculty of Engineering, Universiti Putra Malaysia 43400 Serdang, Selangor (Malaysia)

    2011-02-15

    Accurate modeling of daylight and surface reflectance are very useful for most outdoor machine vision applications specifically those which are based on color recognition. Existing daylight CIE model has drawbacks that limit its ability to predict the color of incident light. These limitations include lack of considering ambient light, effects of light reflected off the ground, and context specific information. Previously developed color model is only tested for a few geographical places in North America and its accountability is under question for other places in the world. Besides, existing surface reflectance models are not easily applied to outdoor images. A reflectance model with combined diffuse and specular reflection in normalized HSV color space could be used to predict color. In this paper, a new daylight color model showing the color of daylight for a broad range of sky conditions is developed which will suit weather conditions of tropical places such as Malaysia. A comparison of this daylight color model and daylight CIE model will be discussed. The colors of matte and specular surfaces have been estimated by use of the developed color model and surface reflection function in this paper. The results are shown to be highly reliable.

  10. Color Vision and Hue Categorization in Young Human Infants

    Science.gov (United States)

    Bornstein, Marc H.; And Others

    1976-01-01

    The main objective of the present investigations was to determine whether or not young human infants see the physical spectrum in a categorical fashion as human adults and animals who possess color vision regularly do. (Author)

  11. Human Object Recognition Using Colour and Depth Information from an RGB-D Kinect Sensor

    Directory of Open Access Journals (Sweden)

    Benjamin John Southwell

    2013-03-01

    Full Text Available Human object recognition and tracking is important in robotics and automation. The Kinect sensor and its SDK have provided a reliable human tracking solution where a constant line of sight is maintained. However, if the human object is lost from sight during the tracking, the existing method cannot recover and resume tracking the previous object correctly. In this paper, a human recognition method is developed based on colour and depth information that is provided from any RGB-D sensor. In particular, the method firstly introduces a mask based on the depth information of the sensor to segment the shirt from the image (shirt segmentation; it then extracts the colour information of the shirt for recognition (shirt recognition. As the shirt segmentation is only based on depth information, it is light invariant compared to colour-based segmentation methods. The proposed colour recognition method introduces a confidence-based ruling method to classify matches. The proposed shirt segmentation and colour recognition method is tested using a variety of shirts with the tracked human at standstill or moving in varying lighting conditions. Experiments show that the method can recognize shirts of varying colours and patterns robustly.

  12. Modeling learned categorical perception in human vision.

    Science.gov (United States)

    Casey, Matthew C; Sowden, Paul T

    2012-09-01

    A long standing debate in cognitive neuroscience has been the extent to which perceptual processing is influenced by prior knowledge and experience with a task. A converging body of evidence now supports the view that a task does influence perceptual processing, leaving us with the challenge of understanding the locus of, and mechanisms underpinning, these influences. An exemplar of this influence is learned categorical perception (CP), in which there is superior perceptual discrimination of stimuli that are placed in different categories. Psychophysical experiments on humans have attempted to determine whether early cortical stages of visual analysis change as a result of learning a categorization task. However, while some results indicate that changes in visual analysis occur, the extent to which earlier stages of processing are changed is still unclear. To explore this issue, we develop a biologically motivated neural model of hierarchical vision processes consisting of a number of interconnected modules representing key stages of visual analysis, with each module learning to exhibit desired local properties through competition. With this system level model, we evaluate whether a CP effect can be generated with task influence to only the later stages of visual analysis. Our model demonstrates that task learning in just the later stages is sufficient for the model to exhibit the CP effect, demonstrating the existence of a mechanism that requires only a high-level of task influence. However, the effect generalizes more widely than is found with human participants, suggesting that changes to earlier stages of analysis may also be involved in the human CP effect, even if these are not fundamental to the development of CP. The model prompts a hybrid account of task-based influences on perception that involves both modifications to the use of the outputs from early perceptual analysis along with the possibility of changes to the nature of that early analysis itself

  13. 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

    Directory of Open Access Journals (Sweden)

    Nurul Farhana Abu Bakar

    2014-01-01

    Full Text Available 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.

  14. Vision Systems with the Human in the Loop

    Directory of Open Access Journals (Sweden)

    Bauckhage Christian

    2005-01-01

    Full Text Available The emerging cognitive vision paradigm deals with vision systems that apply machine learning and automatic reasoning in order to learn from what they perceive. Cognitive vision systems can rate the relevance and consistency of newly acquired knowledge, they can adapt to their environment and thus will exhibit high robustness. This contribution presents vision systems that aim at flexibility and robustness. One is tailored for content-based image retrieval, the others are cognitive vision systems that constitute prototypes of visual active memories which evaluate, gather, and integrate contextual knowledge for visual analysis. All three systems are designed to interact with human users. After we will have discussed adaptive content-based image retrieval and object and action recognition in an office environment, the issue of assessing cognitive systems will be raised. Experiences from psychologically evaluated human-machine interactions will be reported and the promising potential of psychologically-based usability experiments will be stressed.

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

    Science.gov (United States)

    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.

  16. Synaesthesia and colour constancy.

    Science.gov (United States)

    Erskine, Holly; Mattingley, Jason B; Arnold, Derek H

    2013-04-01

    Grapheme-colour synaesthesia is an atypical condition characterized by the perception of colours when reading achromatic text. We investigated the level of colour processing responsible for these experiences. To do so, we tapped a central characteristic of colour perception. In different lighting conditions the same wavelength of light can prompt the perception of different colours. This helps humans recognize distinctive coloured objects despite changes in illumination. We wanted to see if synaesthetic colours were generated at a neural locus that was susceptible to colour constancy analyses. We used colour matching and naming tasks to examine interactions between simulated coloured illuminants and synaesthetic colours. Neither synaesthetic colour matching or naming was impacted. This contrasted with non-synaesthetic control participants, who performed the colour-matching task with graphemes physically coloured to mimic synaesthesia. Our data suggest that synaesthetic colour signals are not generated at lower-levels of colour processing, but are introduced at higher levels of analysis and are therefore not impacted by the processes responsible for perceptual constancy.

  17. The unsuitability of HTML-based colour charts for estimating animal colours--a comment on Berggren and Merilä (2004).

    Science.gov (United States)

    Stevens, Martin; Cuthill, Innes C

    2005-08-30

    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. 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. 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

  18. The unsuitability of html-based colour charts for estimating animal colours – a comment on Berggren and Merilä (2004

    Directory of Open Access Journals (Sweden)

    Cuthill Innes C

    2005-08-01

    Full Text Available Abstract 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

  19. MEG studies of human vision: Retinotopic organization of V1

    Energy Technology Data Exchange (ETDEWEB)

    Aine, C.; George, J.; Ranken, D.; Best, E.; Tiee, W.; Vigil, V.; Flynn, E.; Wood, C. [Los Alamos National Lab., NM (United States); Supek, S. [Zagreb Univ. (Croatia). Dept. of Physics

    1993-12-31

    A primary goal of noninvasive studies of human vision is to identify and characterize multiple visual areas in the human brain analogous to those identified in studies of nonhuman primates. By combining functional MEG measurements with images of individual anatomy derived from MRI, the authors hope to determine the location and arrangement of multiple visual areas in human cortex and to probe their functional significance. The authors have identified several different visual areas thus far which appear to be topographically organized. This paper focuses on the retinotopic characterization of the primary visual area (V1) in humans.

  20. Future Visions for Scientific Human Exploration

    Science.gov (United States)

    Garvin, James

    2005-01-01

    Today, humans explore deep-space locations such as Mars, asteroids, and beyond, vicariously here on Earth, with noteworthy success. However, to achieve the revolutionary breakthroughs that have punctuated the history of science since the dawn of the Space Age has always required humans as "the discoverers," as Daniel Boorstin contends in this book of the same name. During Apollo 17, human explorers on the lunar surface discovered the "genesis rock," orange glass, and humans in space revamped the optically crippled Hubble Space Telescope to enable some of the greatest astronomical discoveries of all time. Science-driven human exploration is about developing the opportunities for such events, perhaps associated with challenging problems such as whether we can identify life beyond Earth within the universe. At issue, however, is how to safely insert humans and the spaceflight systems required to allow humans to operate as they do best in the hostile environment of deep space. The first issue is minimizing the problems associated with human adaptation to the most challenging aspects of deep space space radiation and microgravity (or non-Earth gravity). One solution path is to develop technologies that allow for minimization of the exposure time of people to deep space, as was accomplished in Apollo. For a mission to the planet Mars, this might entail new technological solutions for in-space propulsion that would make possible time-minimized transfers to and from Mars. The problem of rapid, reliable in-space transportation is challenged by the celestial mechanics of moving in space and the so-called "rocket equation." To travel to Mars from Earth in less than the time fuel-minimizing trajectories allow (i.e., Hohmann transfers) requires an exponential increase in the amount of fuel. Thus, month-long transits would require a mass of fuel as large as the dry mass of the ISS, assuming the existence of continuous acceleration engines. This raises the largest technological

  1. Synthetic vision and emotion calculation in intelligent virtual human modeling.

    Science.gov (United States)

    Zhao, Y; Kang, J; Wright, D K

    2007-01-01

    The virtual human technique can already provide vivid and believable human behaviour in more and more scenarios. Virtual humans are expected to replace real humans in hazardous situations to undertake tests and feed back valuable information. This paper will introduce a virtual human with a novel collision-based synthetic vision, short-term memory model and a capability to implement emotion calculation and decision making. The virtual character based on this model can 'see' what is in its field of view (FOV) and remember those objects. After that, a group of affective computing equations have been introduced. These equations have been implemented into a proposed emotion calculation process to enlighten emotion for virtual intelligent humans.

  2. Colour constancy in insects.

    Science.gov (United States)

    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.

  3. Helicopter flights with night-vision goggles: Human factors aspects

    Science.gov (United States)

    Brickner, Michael S.

    1989-01-01

    Night-vision goggles (NVGs) and, in particular, the advanced, helmet-mounted Aviators Night-Vision-Imaging System (ANVIS) allows helicopter pilots to perform low-level flight at night. It consists of light intensifier tubes which amplify low-intensity ambient illumination (star and moon light) and an optical system which together produce a bright image of the scene. However, these NVGs do not turn night into day, and, while they may often provide significant advantages over unaided night flight, they may also result in visual fatigue, high workload, and safety hazards. These problems reflect both system limitations and human-factors issues. A brief description of the technical characteristics of NVGs and of human night-vision capabilities is followed by a description and analysis of specific perceptual problems which occur with the use of NVGs in flight. Some of the issues addressed include: limitations imposed by a restricted field of view; problems related to binocular rivalry; the consequences of inappropriate focusing of the eye; the effects of ambient illumination levels and of various types of terrain on image quality; difficulties in distance and slope estimation; effects of dazzling; and visual fatigue and superimposed symbology. These issues are described and analyzed in terms of their possible consequences on helicopter pilot performance. The additional influence of individual differences among pilots is emphasized. Thermal imaging systems (forward looking infrared (FLIR)) are described briefly and compared to light intensifier systems (NVGs). Many of the phenomena which are described are not readily understood. More research is required to better understand the human-factors problems created by the use of NVGs and other night-vision aids, to enhance system design, and to improve training methods and simulation techniques.

  4. A pseudoisochromatic test of color vision for human infants.

    Science.gov (United States)

    Mercer, Michele E; Drodge, Suzanne C; Courage, Mary L; Adams, Russell J

    2014-07-01

    Despite the development of experimental methods capable of measuring early human color vision, we still lack a procedure comparable to those used to diagnose the well-identified congenital and acquired color vision anomalies in older children, adults, and clinical patients. In this study, we modified a pseudoisochromatic test to make it more suitable for young infants. Using a forced choice preferential looking procedure, 216 3-to-23-mo-old babies were tested with pseudoisochromatic targets that fell on either a red/green or a blue/yellow dichromatic confusion axis. For comparison, 220 color-normal adults and 22 color-deficient adults were also tested. Results showed that all babies and adults passed the blue/yellow target but many of the younger infants failed the red/green target, likely due to the interaction of the lingering immaturities within the visual system and the small CIE vector distance within the red/green plate. However, older (17-23 mo) infants, color- normal adults and color-defective adults all performed according to expectation. Interestingly, performance on the red/green plate was better among female infants, well exceeding the expected rate of genetic dimorphism between genders. Overall, with some further modification, the test serves as a promising tool for the detection of early color vision anomalies in early human life.

  5. Episodic Reasoning for Vision-Based Human Action Recognition

    Directory of Open Access Journals (Sweden)

    Maria J. Santofimia

    2014-01-01

    Full Text Available Smart Spaces, Ambient Intelligence, and Ambient Assisted Living are environmental paradigms that strongly depend on their capability to recognize human actions. While most solutions rest on sensor value interpretations and video analysis applications, few have realized the importance of incorporating common-sense capabilities to support the recognition process. Unfortunately, human action recognition cannot be successfully accomplished by only analyzing body postures. On the contrary, this task should be supported by profound knowledge of human agency nature and its tight connection to the reasons and motivations that explain it. The combination of this knowledge and the knowledge about how the world works is essential for recognizing and understanding human actions without committing common-senseless mistakes. This work demonstrates the impact that episodic reasoning has in improving the accuracy of a computer vision system for human action recognition. This work also presents formalization, implementation, and evaluation details of the knowledge model that supports the episodic reasoning.

  6. Vision Influence on Whole-Body Human Vibration Comfort Levels

    Directory of Open Access Journals (Sweden)

    Maria Lúcia Machado Duarte

    2006-01-01

    Full Text Available The well being of people needs to be a priority in the modern world. In that respect, vibration cannot be one more cause of stress. Besides that, vibration comfort is very important, since high levels may cause health or even tasks' accomplishment problems. Several parameters may influence the levels of vibration a human being supports. Among them, one can mention the influence of gender, age, corporeal mass index (CMI, temperature, humor, anxiety, hearing, posture, vision, etc. The first three parameters mentioned were already investigated in previous studies undertaken by GRAVI (Group of Acoustics and Vibration researchers. In this paper, the influence of vision is evaluated. The main objective with this series of tests performed is to try to quantify in a future the influence of each parameter in a global vibration comfort level. Conclusions are presented for the parameter investigated.

  7. Human vision is determined based on information theory.

    Science.gov (United States)

    Delgado-Bonal, Alfonso; Martín-Torres, Javier

    2016-11-03

    It is commonly accepted that the evolution of the human eye has been driven by the maximum intensity of the radiation emitted by the Sun. However, the interpretation of the surrounding environment is constrained not only by the amount of energy received but also by the information content of the radiation. Information is related to entropy rather than energy. The human brain follows Bayesian statistical inference for the interpretation of visual space. The maximization of information occurs in the process of maximizing the entropy. Here, we show that the photopic and scotopic vision absorption peaks in humans are determined not only by the intensity but also by the entropy of radiation. We suggest that through the course of evolution, the human eye has not adapted only to the maximum intensity or to the maximum information but to the optimal wavelength for obtaining information. On Earth, the optimal wavelengths for photopic and scotopic vision are 555 nm and 508 nm, respectively, as inferred experimentally. These optimal wavelengths are determined by the temperature of the star (in this case, the Sun) and by the atmospheric composition.

  8. Human vision is determined based on information theory

    Science.gov (United States)

    Delgado-Bonal, Alfonso; Martín-Torres, Javier

    2016-11-01

    It is commonly accepted that the evolution of the human eye has been driven by the maximum intensity of the radiation emitted by the Sun. However, the interpretation of the surrounding environment is constrained not only by the amount of energy received but also by the information content of the radiation. Information is related to entropy rather than energy. The human brain follows Bayesian statistical inference for the interpretation of visual space. The maximization of information occurs in the process of maximizing the entropy. Here, we show that the photopic and scotopic vision absorption peaks in humans are determined not only by the intensity but also by the entropy of radiation. We suggest that through the course of evolution, the human eye has not adapted only to the maximum intensity or to the maximum information but to the optimal wavelength for obtaining information. On Earth, the optimal wavelengths for photopic and scotopic vision are 555 nm and 508 nm, respectively, as inferred experimentally. These optimal wavelengths are determined by the temperature of the star (in this case, the Sun) and by the atmospheric composition.

  9. Supervised Object Class Colour Normalisation

    DEFF Research Database (Denmark)

    Riabchenko, Ekatarina; Lankinen, Jukka; Buch, Anders Glent;

    2013-01-01

    Colour is an important cue in many applications of computer vision and image processing, but robust usage often requires estimation of the unknown illuminant colour. Usually, to obtain images invariant to the illumination conditions under which they were taken, color normalisation is used....... In this work, we develop a such colour normalisation technique, where true colours are not important per se but where examples of same classes have photometrically consistent appearance. This is achieved by supervised estimation of a class specic canonical colour space where the examples have minimal variation...

  10. Shape perception in human and computer vision an interdisciplinary perspective

    CERN Document Server

    Dickinson, Sven J

    2013-01-01

    This comprehensive and authoritative text/reference presents a unique, multidisciplinary perspective on Shape Perception in Human and Computer Vision. Rather than focusing purely on the state of the art, the book provides viewpoints from world-class researchers reflecting broadly on the issues that have shaped the field. Drawing upon many years of experience, each contributor discusses the trends followed and the progress made, in addition to identifying the major challenges that still lie ahead. Topics and features: examines each topic from a range of viewpoints, rather than promoting a speci

  11. Vision-based Human Gender Recognition: A Survey

    CERN Document Server

    Ng, Choon Boon; Goi, Bok Min

    2012-01-01

    Gender is an important demographic attribute of people. This paper provides a survey of human gender recognition in computer vision. A review of approaches exploiting information from face and whole body (either from a still image or gait sequence) is presented. We highlight the challenges faced and survey the representative methods of these approaches. Based on the results, good performance have been achieved for datasets captured under controlled environments, but there is still much work that can be done to improve the robustness of gender recognition under real-life environments.

  12. The evolution of human skin colouration and its relevance to health in the modern world.

    Science.gov (United States)

    Jablonski, N G

    2012-03-01

    Functionally naked skin which comes in a range of colours is unique to the human species. This review summarises current evidence pertaining to the evolution of these attributes. The biggest changes in the integument occurred during the course of human evolution in equatorial Africa, under regimes of high daytime temperatures and high ultraviolet radiation (UVR). Loss of most functional body hair was accompanied by the evolution of an epidermis with a specialised stratum corneum and permanent, protective, eumelanin pigmentation. The main reason for the evolution of dark pigmentation was to protect against folate deficiency caused by elevated demands for folate in cell division, DNA repair, and melanogenesis stimulated by UVR. Dispersal out of tropical Africa created new challenges for human physiology especially because of lower and more seasonal levels of UVR and ultraviolet B (UVB) outside of the tropics. In these environments, the challenge of producing a vitamin D precursor in the skin from available UVB was met by natural selection acting on mutations capable of producing varying degrees of depigmentation. The range of pigmentation observed in modern humans today is, thus, the product of two opposing clines, one favoring photoprotection near the equator, the other favoring vitamin D photosynthesis nearer the poles. Recent migrations and changes in lifestyle in the last 500 years have brought many humans into UVR regimes different from those experienced by their ancestors and, accordingly, exposed them to new disease risks, including skin cancer and vitamin D deficiency.

  13. Bona fide colour: DNA prediction of human eye and hair colour from ancient and contemporary skeletal remains

    NARCIS (Netherlands)

    J. Draus-Barini (Jolanta); S. Walsh (Susan); E. Pośpiech (Ewelina); T. Kupiec (Tomasz); H. Głab (Henryk); W. Branicki (Wojciech); M.H. Kayser (Manfred)

    2013-01-01

    textabstractBackground: DNA analysis of ancient skeletal remains is invaluable in evolutionary biology for exploring the history of species, including humans. Contemporary human bones and teeth, however, are relevant in forensic DNA analyses that deal with the identification of perpetrators, missing

  14. Bona fide colour: DNA prediction of human eye and hair colour from ancient and contemporary skeletal remains

    NARCIS (Netherlands)

    J. Draus-Barini (Jolanta); S. Walsh (Susan); E. Pośpiech (Ewelina); T. Kupiec (Tomasz); H. Głab (Henryk); W. Branicki (Wojciech); M.H. Kayser (Manfred)

    2013-01-01

    textabstractBackground: DNA analysis of ancient skeletal remains is invaluable in evolutionary biology for exploring the history of species, including humans. Contemporary human bones and teeth, however, are relevant in forensic DNA analyses that deal with the identification of perpetrators, missing

  15. Atoms of recognition in human and computer vision.

    Science.gov (United States)

    Ullman, Shimon; Assif, Liav; Fetaya, Ethan; Harari, Daniel

    2016-03-01

    Discovering the visual features and representations used by the brain to recognize objects is a central problem in the study of vision. Recently, neural network models of visual object recognition, including biological and deep network models, have shown remarkable progress and have begun to rival human performance in some challenging tasks. These models are trained on image examples and learn to extract features and representations and to use them for categorization. It remains unclear, however, whether the representations and learning processes discovered by current models are similar to those used by the human visual system. Here we show, by introducing and using minimal recognizable images, that the human visual system uses features and processes that are not used by current models and that are critical for recognition. We found by psychophysical studies that at the level of minimal recognizable images a minute change in the image can have a drastic effect on recognition, thus identifying features that are critical for the task. Simulations then showed that current models cannot explain this sensitivity to precise feature configurations and, more generally, do not learn to recognize minimal images at a human level. The role of the features shown here is revealed uniquely at the minimal level, where the contribution of each feature is essential. A full understanding of the learning and use of such features will extend our understanding of visual recognition and its cortical mechanisms and will enhance the capacity of computational models to learn from visual experience and to deal with recognition and detailed image interpretation.

  16. Extreme reaction times determine fluctuation scaling in human color vision

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2016-11-01

    In modern mental chronometry, human reaction time defines the time elapsed from stimulus presentation until a response occurs and represents a reference paradigm for investigating stochastic latency mechanisms in color vision. Here we examine the statistical properties of extreme reaction times and whether they support fluctuation scaling in the skewness-kurtosis plane. Reaction times were measured for visual stimuli across the cardinal directions of the color space. For all subjects, the results show that very large reaction times deviate from the right tail of reaction time distributions suggesting the existence of dragon-kings events. The results also indicate that extreme reaction times are correlated and shape fluctuation scaling over a wide range of stimulus conditions. The scaling exponent was higher for achromatic than isoluminant stimuli, suggesting distinct generative mechanisms. Our findings open a new perspective for studying failure modes in sensory-motor communications and in complex networks.

  17. Characterising the variations in ethnic skin colours: a new calibrated data base for human skin

    OpenAIRE

    Xiao, K.; Yates, JM; Zardawi, F; Sueeprasan, S.; Liao, N; Gill, L.; Li, C; Wuerger, S

    2017-01-01

    Background: Accurate skin colour measurements are important for numerous medical applications including the diagnosis and treatment of cutaneous disorders and the provision of maxillofacial soft tissue prostheses. Methods: In this study, we obtained accurate skin colour measurements from four different ethnic groups (Caucasian, Chinese, Kurdish, Thai) and at four different body locations (Forehead, cheek, inner arm, back of hand) with a view of establishing a new skin colour database for medi...

  18. Characterising the variations in ethnic skin colours: a new calibrated data base for human skin.

    Science.gov (United States)

    Xiao, K; Yates, J M; Zardawi, F; Sueeprasan, S; Liao, N; Gill, L; Li, C; Wuerger, S

    2017-02-01

    Accurate skin colour measurements are important for numerous medical applications including the diagnosis and treatment of cutaneous disorders and the provision of maxillofacial soft tissue prostheses. In this study, we obtained accurate skin colour measurements from four different ethnic groups (Caucasian, Chinese, Kurdish, Thai) and at four different body locations (Forehead, cheek, inner arm, back of hand) with a view of establishing a new skin colour database for medical and cosmetic applications. Skin colours are measured using a spectrophotometer and converted to a device-independent standard colour appearance space (CIELAB) where skin colour is expressed as values along the three dimensions: Lightness L*, Redness a* and Yellowness b*. Skin colour differences and variation are then evaluated as a function of ethnicity and body location. We report three main results: (1) When plotted in a standard colour appearance space (CIELAB), skin colour distributions for the four ethnic groups overlap significantly, although there are systematic mean differences. Between ethnicities, the most significant skin colour differences occur along the yellowness dimension, with Thai skin exhibiting the highest yellowness (b*) value and Caucasian skin the lowest value. Facial redness (a*) is invariant across the four ethnic groups. (2) Between different body locations, there are significant variations in redness (a*), with the forehead showing the highest redness value and the inner arm the lowest. (3) The colour gamut is smallest in the Chinese sample and largest in the Caucasian sample, with the Chinese gamut lying entirely the Caucasian gamut. Similarly, the largest variability in skin tones is found in the Caucasian group, and the smallest in the Chinese group. Broadly speaking, skin colour variation can be explained by two main factors: individual differences in lightness and yellowness are mostly due to ethnicity, whereas differences in redness are primarily due to

  19. Adaptive colouration in amphibians.

    Science.gov (United States)

    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.

  20. A Return to the Human in Humanism: A Response to Hansen's Humanistic Vision

    Science.gov (United States)

    Lemberger, Matthew E.

    2012-01-01

    In his extension of the humanistic vision, Hansen (2012) recommends that counseling practitioners and scholars adopt operations that are consistent with his definition of a multiple-perspective philosophy. Alternatively, the author of this article believes that Hansen has reduced the capacity of the human to interpret meaning through quantitative…

  1. The brightness of colour.

    Directory of Open Access Journals (Sweden)

    David Corney

    Full Text Available BACKGROUND: The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this 'illusion' to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies. RESULTS: Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1, if not earlier in the visual system, since the brightness of colours (as opposed to their luminance accords with activity in V1 as measured with fMRI. CONCLUSIONS: The data suggest that perceptions

  2. Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

    Institute of Scientific and Technical Information of China (English)

    MU GuoGuang; WANG ZhaoQi; LIU YongJi; QUAN Wei; WANG Yang; WANG Wei

    2007-01-01

    In this paper we present the recent research results in the field of vision correction and supernormal vision according to the actual measurements of the wave-front aberrations and the corneal surface topography, the clinical detection of the visual function and the laser corneal refractive surgery, and the optimization of the optical system. These include the features of the aberrations of human eye with different pupil sizes, different fields of view and temporal accommodation, the influence of the polychromatic illumination of the visible wavelength on the supernormal vision,and the effect of the existing laser corneal refractive surgery on the wave-front aberrations of the eye. It is shown that the wave-front aberration of human eye is of temporal variation and of synthesis with multi impact factors. To achieve supernormal vision, an optimum engineering data for the customized laser corneal surgery should be firstly acquired, which may involve the dynamic free-form optical surface. Although the myopia can be corrected by the laser in situ keratomileusis (LASlK) in a certain degree, it brings about negative effects under scotopic conditions.

  3. Optical study on the vision correction and supernormal vision based on the wave-front aberrations of human eye

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper we present the recent research results in the field of vision correction and supernormal vision according to the actual measurements of the wave-front aberrations and the corneal surface topography,the clinical detection of the visual function and the laser corneal refractive surgery,and the optimization of the optical system. These include the features of the aberrations of human eye with different pupil sizes,different fields of view and temporal accommodation,the influence of the polychromatic illumination of the visible wavelength on the supernormal vision,and the effect of the existing laser corneal refractive surgery on the wave-front ab-errations of the eye. It is shown that the wave-front aberration of human eye is of temporal variation and of synthesis with multi impact factors. To achieve super-normal vision,an optimum engineering data for the customized laser corneal sur-gery should be firstly acquired,which may involve the dynamic free-form optical surface. Although the myopia can be corrected by the laser in situ keratomileusis(LASIK) in a certain degree,it brings about negative effects under scotopic condi-tions.

  4. Colour Studies

    African Journals Online (AJOL)

    DR Nneka

    2015-04-14

    Apr 14, 2015 ... behaviour of colour and develop colour originality through creative construction and ... augmented by advertising that links color to desire for everything ...... Illusion's Bias on Serving and Eating Behaviour Journal of consumer.

  5. Colour preferences of UK garden birds at supplementary seed feeders.

    Science.gov (United States)

    Rothery, Luke; Scott, Graham W; Morrell, Lesley J

    2017-01-01

    Supplementary feeding of garden birds generally has benefits for both bird populations and human wellbeing. Birds have excellent colour vision, and show preferences for food items of particular colours, but research into colour preferences associated with artificial feeders is limited to hummingbirds. Here, we investigated the colour preferences of common UK garden birds foraging at seed-dispensing artificial feeders containing identical food. We presented birds simultaneously with an array of eight differently coloured feeders, and recorded the number of visits made to each colour over 370 30-minute observation periods in the winter of 2014/15. In addition, we surveyed visitors to a garden centre and science festival to determine the colour preferences of likely purchasers of seed feeders. Our results suggest that silver and green feeders were visited by higher numbers of individuals of several common garden bird species, while red and yellow feeders received fewer visits. In contrast, people preferred red, yellow, blue and green feeders. We suggest that green feeders may be simultaneously marketable and attractive to foraging birds.

  6. Colour preferences of UK garden birds at supplementary seed feeders

    Science.gov (United States)

    Rothery, Luke; Scott, Graham W.

    2017-01-01

    Supplementary feeding of garden birds generally has benefits for both bird populations and human wellbeing. Birds have excellent colour vision, and show preferences for food items of particular colours, but research into colour preferences associated with artificial feeders is limited to hummingbirds. Here, we investigated the colour preferences of common UK garden birds foraging at seed-dispensing artificial feeders containing identical food. We presented birds simultaneously with an array of eight differently coloured feeders, and recorded the number of visits made to each colour over 370 30-minute observation periods in the winter of 2014/15. In addition, we surveyed visitors to a garden centre and science festival to determine the colour preferences of likely purchasers of seed feeders. Our results suggest that silver and green feeders were visited by higher numbers of individuals of several common garden bird species, while red and yellow feeders received fewer visits. In contrast, people preferred red, yellow, blue and green feeders. We suggest that green feeders may be simultaneously marketable and attractive to foraging birds. PMID:28212435

  7. The Metric of Colour Space

    DEFF Research Database (Denmark)

    Gravesen, Jens

    2015-01-01

    The space of colours is a fascinating space. It is a real vector space, but no matter what inner product you put on the space the resulting Euclidean distance does not correspond to human perception of difference between colours. In 1942 MacAdam performed the first experiments on colour matching ...

  8. A Possible Model of Noise Enhanced Visual Perception in Human Vision

    CERN Document Server

    Kundu, Ajanta

    2010-01-01

    We demonstrate, through simulation, that a simple centre surround receptive field of vision is capable of exhibiting stochastic resonance. We also show that this could be used to model the nature of contrast sensitivity enhancement of human vision, through stochastic resonance, observed in psychophysical experiments.

  9. Vision-based navigation in a dynamic environment for virtual human

    Science.gov (United States)

    Liu, Yan; Sun, Ji-Zhou; Zhang, Jia-Wan; Li, Ming-Chu

    2004-06-01

    Intelligent virtual human is widely required in computer games, ergonomics software, virtual environment and so on. We present a vision-based behavior modeling method to realize smart navigation in a dynamic environment. This behavior model can be divided into three modules: vision, global planning and local planning. Vision is the only channel for smart virtual actor to get information from the outside world. Then, the global and local planning module use A* and D* algorithm to find a way for virtual human in a dynamic environment. Finally, the experiments on our test platform (Smart Human System) verify the feasibility of this behavior model.

  10. Colour Sonar: Multi-Frequency Sidescan Sonar Images of the Seabed in the Inner Sound of the Pentland Firth, Scotland

    Directory of Open Access Journals (Sweden)

    Duncan Tamsett

    2016-03-01

    Full Text Available The backscatter response of a seabed to an incident sonar signal is dependent on the carrier wave frequency: i.e., the seabed is acoustically colourful. Colour is implemented in a prototype three-frequency sidescan sonar system deployed in the Pentland Firth, north Scotland. Sonar amplitude data as a function of frequency are processed to render them an unconfounded effect of the seabed normalized to the response at a reference inclination angle, for colour to be a meaningful property of the seabed. Methods for mapping data at sonar frequencies to optical primary colours for human visualisation are explored. We recommend methods that in our opinion generate colour characteristics harmonious with human vision in which: shadow is white; saturation black; colour shade darkness is proportional to backscatter strength; and shades of red, green and blue are seen in proportion to the backscatter amplitudes of the low-, mid- and high-frequency sonar data. Frequency equalisation is applied to achieve a balance in colour responses in images. The seabed in the survey area is acoustically colourful. Using the “negative BGR” colour mapping method: a weakly backscattering sand dune in the north of the survey area appears as shades of light blue and purple; a strongly backscattering halo of cobbles around the dune appears as shades of hazel brown; a strongly backscattering gravel ridge across the south of the survey area appears as shades of royal blue; and exposed rock as textures ranging in colour from light brown to light blue/green. There is evidence for colour anisotropy (a dependence of colour on the direction of ensonification. Similarities between anthropic colour sonar and the natural sonar of Microchiropteran bats are noted. Bats’ sonar satisfies the information criteria for acoustic colour, and it is hypothesized that it informs a colourfully-perceived world view.

  11. DISTANCE MEASURING MODELING AND ERROR ANALYSIS OF DUAL CCD VISION SYSTEM SIMULATING HUMAN EYES AND NECK

    Institute of Scientific and Technical Information of China (English)

    Wang Xuanyin; Xiao Baoping; Pan Feng

    2003-01-01

    A dual-CCD simulating human eyes and neck (DSHEN) vision system is put forward. Its structure and principle are introduced. The DSHEN vision system can perform some movements simulating human eyes and neck by means of four rotating joints, and realize precise object recognizing and distance measuring in all orientations. The mathematic model of the DSHEN vision system is built, and its movement equation is solved. The coordinate error and measure precision affected by the movement parameters are analyzed by means of intersection measuring method. So a theoretic foundation for further research on automatic object recognizing and precise target tracking is provided.

  12. Population Spotting Using Big Data: Validating the Human Performance Concept of Operations Analytic Vision

    Science.gov (United States)

    2017-01-01

    AFRL-SA-WP-SR-2017-0001 Population Spotting Using “ Big Data ”: Validating the Human Performance Concept of Operations Analytic Vision...TITLE AND SUBTITLE Population Spotting Using “ Big Data ”: Validating the Human Performance Concept of Operations Analytic Vision 5a. CONTRACT...STINFO COPY NOTICE AND SIGNATURE PAGE Using Government drawings, specifications, or other data included in this document for any

  13. Measuring Colour

    CERN Document Server

    Hunt, R W G

    2011-01-01

    The classic authority on colour measurement now fully revised and updated with the latest CIE recommendations The measurement of colour is of major importance in many commercial applications, such as the textile, paint, and foodstuff industries; as well as having a significant role in the lighting, paper, printing, cosmetic, plastics, glass, chemical, photographic, television, transport, and communication industries. Building upon the success of earlier editions, the 4th edition of Measuring Colour has been updated throughout with new chapters on colour rendering by light sources; colorimetry

  14. A new vision for the science of human flavor perception

    Directory of Open Access Journals (Sweden)

    Gordon M Shepherd

    2014-07-01

    Full Text Available The conference was organized and welcomed by Lisa Sasson, representing the NYU Steinhardt School and its Department of Food Science, Nutrition and Public Health in cooperation with the NYU School of Dentistry. As a co-organizer, I added my welcome, and explained how the many disciplines brought together in the conference constituted a new vision for the science of human flavor perception, which can be summarized by the term “neurogastronomy” (1. The speakers and the disciplines they represent were bound together by several principles. First, "Nothing in biology makes sense except in the light of evolution." This is understood to apply to most research in biology; here we wished to show that it applies especially to the human behavior of choosing foods to eat, a view put forward most prominently by Richard Wrangham based on his book "Catching Fire: How Cooking Made Us Human". We also wished to show that the sensory and motor apparatus of the mouth and nose need to be understood as adaptations through human evolution, as carefully documented by Daniel Lieberman, based on his recent "Evolution of the Human Head". Many of the speakers picked up this theme in their presentations. It is clear that an evolutionary framework must be part of understanding flavor and healthy eating. A second principle was that "Flavor is not in the food; it is created by the brain". Just as color is created out of different wavelengths of light by neural processing mechanisms in our brains, so is flavor created by neural processing mechanisms out of different molecules emitted by the food and drink in our mouths. This requires understanding neural mechanisms at all levels of organization of the brain, a vast field that our conference only began to address, starting with the sensory receptors and sensory systems as discussed by Gary Beauchamp for taste and Stuart Firestein for olfaction. Current research reported by Ivan De Araujo on sugars is dissociating their sweet

  15. Digital image processing and analysis human and computer vision applications with CVIPtools

    CERN Document Server

    Umbaugh, Scott E

    2010-01-01

    Section I Introduction to Digital Image Processing and AnalysisDigital Image Processing and AnalysisOverviewImage Analysis and Computer VisionImage Processing and Human VisionKey PointsExercisesReferencesFurther ReadingComputer Imaging SystemsImaging Systems OverviewImage Formation and SensingCVIPtools SoftwareImage RepresentationKey PointsExercisesSupplementary ExercisesReferencesFurther ReadingSection II Digital Image Analysis and Computer VisionIntroduction to Digital Image AnalysisIntroductionPreprocessingBinary Image AnalysisKey PointsExercisesSupplementary ExercisesReferencesFurther Read

  16. Assessment of colour differences in silicone hand and digit prostheses: perceptible and acceptable thresholds for fair and dark skin shades.

    Science.gov (United States)

    Leow, Michael E L; Ow, Richard K K; Lee, Man Hang; Huak, Chan Yiong; Pho, Robert W H

    2006-04-01

    This study addresses the dilemma of initial clinical and social acceptance of a newly fabricated silicone prosthesis in relation to its colour match to the natural skin. This was achieved by derivation of specific colour difference thresholds defining perceptible and acceptable levels of colour sensitivity. Two separate sets of 10 fair and dark shade digit prosthesis samples were each fabricated with a stepped increase in colour difference (deltaE) against the baseline hand prosthesis. Ninety individuals with normal colour vision scores were selected as colour assessors. The colour difference of each prosthesis in the two series was evaluated visually against the baseline by the assessors, using defined scores. The thresholds for perceptible and acceptable colour difference determined in this study were deltaE= 0.8 and deltaE= 1.8 for the fair series and deltaE = 1.3 and deltaE = 2.6 for the dark series, respectively. The acceptable threshold values differed from the perceptible threshold values by deltaE= 1.0 for the fair-shade samples and deltaE= 1.3 for the dark-shade samples. This study demonstrated that subjective visual assessment is positively correlated with deltaE values computed from colorimetric measurements for both fair and dark-shade silicone samples (passessing colour differences. These observations emphasize the importance of subjective feedback on colour by the patient, provided the latter has perfect colour-tested vision. The study also showed that human subjects were less sensitive to perceived colour differences in darker-shade than fairer-shade samples (p < 0.001). This finding seems relevant in a clinical setting involving a multi-ethnic patient population.

  17. Machine vision based on the concept of contrast sensitivity of the human eye

    Science.gov (United States)

    Bezzubik, Vitali; Belashenkov, Nikolai; Vdovin, Gleb

    2014-09-01

    The model of contrast sensitivity function (CSF) of machine vision system, based on the CSF of the human visual system is proposed. By analogy with the human eye, we employ the concept of ganglion cell receptive field to the artificial light-sensitive elements. By further following this concept, we introduced quantative metrics of local and global contrast of digital image. We suggested that the contrast sensitivity threshold forms an iso-line in the parameter space contrast - spatial frequency. The model, implemented in a computer vision system, has been compared to the results of contrast sensitivity research, conducted directly with the human visual system, and demonstrated a good match.

  18. A Survey of Advances in Vision-Based Human Motion Capture and Analysis

    DEFF Research Database (Denmark)

    Moeslund, Thomas B.; Hilton, Adrian; Krüger, Volker

    2006-01-01

    This survey reviews advances in human motion capture and analysis from 2000 to 2006, following a previous survey of papers up to 2000 Human motion capture continues to be an increasingly active research area in computer vision with over 350 publications over this period. A number of significant r...... actions and behavior. This survey reviews recent trends in video based human capture and analysis, as well as discussing open problems for future research to achieve automatic visual analysis of human movement....

  19. An Active Stereo Vision System Based on Neural Pathways of Human Binocular Motor System

    Institute of Scientific and Technical Information of China (English)

    Yu-zhang Gu; Makoto Sato; Xiao-lin Zhang

    2007-01-01

    An active stereo vision system based on a model of neural pathways of human binocular motor system is proposed. With this model, it is guaranteed that the two cameras of the active stereo vision system can keep their lines of sight fixed on the same target object during smooth pursuit. This feature is very important for active stereo vision systems, since not only 3D reconstruction needs the two cameras have an overlapping field of vision, but also it can facilitate the 3D reconstruction algorithm. To evaluate the effectiveness of the proposed method, some software simulations are done to demonstrate the same target tracking characteristic in a virtual environment apt to mistracking easily. Here, mistracking means two eyes track two different objects separately. Then the proposed method is implemented in our active stereo vision system to perform real tracking task in a laboratory scene where several persons walk self-determining. Before the proposed model is implemented in the system, mistracking occurred frequently. After it is enabled, mistracking never occurred. The result shows that the vision system based on neural pathways of human binocular motor system can reliably avoid mistracking.

  20. Applying artificial vision models to human scene understanding

    Directory of Open Access Journals (Sweden)

    Elissa Michele Aminoff

    2015-02-01

    Full Text Available How do we understand the complex patterns of neural responses that underlie scene understanding? Studies of the network of brain regions held to be scene-selective – the parahippocampal/lingual region (PPA, the retrosplenial complex (RSC, and the occipital place area (TOS – have typically focused on single visual dimensions (e.g., size, rather than the high-dimensional feature space in which scenes are likely to be neurally represented. Here we leverage well-specified artificial vision systems to explicate a more complex understanding of how scenes are encoded in this functional network. We correlated similarity matrices within three different scene-spaces arising from: 1 BOLD activity in scene-selective brain regions; 2 behavioral measured judgments of visually-perceived scene similarity; and 3 several different computer vision models. These correlations revealed: 1 models that relied on mid- and high-level scene attributes showed the highest correlations with the patterns of neural activity within the scene-selective network; 2 NEIL and SUN – the models that best accounted for the patterns obtained from PPA and TOS – were different from the GIST model that best accounted for the pattern obtained from RSC; 3 The best performing models outperformed behaviorally-measured judgments of scene similarity in accounting for neural data. One computer vision method – NEIL (Never-Ending-Image-Learner, which incorporates visual features learned as statistical regularities across web-scale numbers of scenes – showed significant correlations with neural activity in all three scene-selective regions and was one of the two models best able to account for variance in the PPA and TOS. We suggest that these results are a promising first step in explicating more fine-grained models of neural scene understanding, including developing a clearer picture of the division of labor among the components of the functional scene-selective brain network.

  1. A Novel Bioinspired Vision System: A Step toward Real-Time Human-Robot Interactions

    Directory of Open Access Journals (Sweden)

    Abdul Rahman Hafiz

    2011-01-01

    Full Text Available Building a human-like robot that could be involved in our daily lives is a dream of many scientists. Achieving a sophisticated robot's vision system, which can enhance the robot's real-time interaction ability with the human, is one of the main keys toward realizing such an autonomous robot. In this work, we are suggesting a bioinspired vision system that helps to develop an advanced human-robot interaction in an autonomous humanoid robot. First, we enhance the robot's vision accuracy online by applying a novel dynamic edge detection algorithm abstracted from the rules that the horizontal cells play in the mammalian retina. Second, in order to support the first algorithm, we improve the robot's tracking ability by designing a variant photoreceptors distribution corresponding to what exists in the human vision system. The experimental results verified the validity of the model. The robot could have a clear vision in real time and build a mental map that assisted it to be aware of the frontal users and to develop a positive interaction with them.

  2. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  3. Night vision goggles, human factors aspects--a questionnaire survey of helicopter aircrew.

    Science.gov (United States)

    Manton, A G

    2000-02-01

    Night vision goggles have become an essential component of military aviation. They provide superior visual capability over unaided night vision, but there are several inherent limitations associated with human factors and systems limitations. This study used a questionnaire survey of Army helicopter aircrew to investigate the incidence of human factors problems which continued after NVG use, with particular reference to visual problems and neck discomfort. It also looked at hardware interaction problems, such as cockpit lighting, and other aspects of NVG use, such as training and aircrew concerns. The issues are described and analysed, and areas of concern, which may have bearings on operational effectiveness and/or safety, have been highlighted.

  4. Discriminative vision-based recovery and recognition of human motion

    NARCIS (Netherlands)

    Poppe, Ronald Walter

    2009-01-01

    The automatic analysis of human motion from images opens up the way for applications in the domains of security and surveillance, human-computer interaction, animation, retrieval and sports motion analysis. In this dissertation, the focus is on robust and fast human pose recovery and action recognit

  5. Using "Competing Visions of Human Rights" in an International IB World School

    Science.gov (United States)

    Tolley, William J.

    2013-01-01

    William Tolley, a teaching fellow with the Choices Program, is the Learning and Innovation Coach and head of history at the International School of Curitiba, Brazil (IB). He writes in this article that he has found that the "Competing Visions of Human Rights" teaching unit, developed by Brown University's Choices Program, provides a…

  6. Using "Competing Visions of Human Rights" in an International IB World School

    Science.gov (United States)

    Tolley, William J.

    2013-01-01

    William Tolley, a teaching fellow with the Choices Program, is the Learning and Innovation Coach and head of history at the International School of Curitiba, Brazil (IB). He writes in this article that he has found that the "Competing Visions of Human Rights" teaching unit, developed by Brown University's Choices Program, provides a…

  7. Two eyes, one vision: binocular motion perception in human visual cortex

    NARCIS (Netherlands)

    Barendregt, M.

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  8. Two eyes, one vision: binocular motion perception in human visual cortex

    NARCIS (Netherlands)

    Barendregt, M.|info:eu-repo/dai/nl/371576792

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  9. A vision and strategy for the virtual physiological human in 2010 and beyond.

    Science.gov (United States)

    Hunter, Peter; Coveney, Peter V; de Bono, Bernard; Diaz, Vanessa; Fenner, John; Frangi, Alejandro F; Harris, Peter; Hose, Rod; Kohl, Peter; Lawford, Pat; McCormack, Keith; Mendes, Miriam; Omholt, Stig; Quarteroni, Alfio; Skår, John; Tegner, Jesper; Randall Thomas, S; Tollis, Ioannis; Tsamardinos, Ioannis; van Beek, Johannes H G M; Viceconti, Marco

    2010-06-13

    European funding under framework 7 (FP7) for the virtual physiological human (VPH) project has been in place now for nearly 2 years. The VPH network of excellence (NoE) is helping in the development of common standards, open-source software, freely accessible data and model repositories, and various training and dissemination activities for the project. It is also helping to coordinate the many clinically targeted projects that have been funded under the FP7 calls. An initial vision for the VPH was defined by framework 6 strategy for a European physiome (STEP) project in 2006. It is now time to assess the accomplishments of the last 2 years and update the STEP vision for the VPH. We consider the biomedical science, healthcare and information and communications technology challenges facing the project and we propose the VPH Institute as a means of sustaining the vision of VPH beyond the time frame of the NoE.

  10. Spectral Test Instrument for Color Vision Measurement

    Institute of Scientific and Technical Information of China (English)

    Balázs Vince Nagy; Gy(o)rgy (A)brahám

    2005-01-01

    Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed are the mixture of these three colours. Consequently these devices can be confusing in testing human color identification, because the spectral distribution of the colors displayed is the combined spectrum of the three primaries. We have developed a new instrument for spectrally correct color vision measurement. This instrument uses light emitting diodes (LEDs) and is capable of producing all spectra of perceivable colors, thus with appropriate test methods this instrument can be a reliable and useful tool in testing human color vision and in verifying color vision correction.

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

    Directory of Open Access Journals (Sweden)

    Jair E Garcia

    Full Text Available 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.(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.(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.

  12. NASA Planetary Science Division Vision 2050 Through Human Exploration

    Science.gov (United States)

    Yun, P. Y.

    2017-02-01

    Next 34 years PSD should play the role of the 21st century-version Lewis and Clark expedition to gather critical information about carefully chosen target celestial bodies in our solar system. PSD missions and human missions will benefit each other.

  13. Covert colour processing in colour agnosia.

    Science.gov (United States)

    Nijboer, Tanja C W; van Zandvoort, Martine J E; de Haan, Edward H F

    2006-01-01

    Patients with colour agnosia can perceive colours and are able to match coloured patches on hue, but are unable to identify or categorise colours. It is a rare condition and there is as yet no agreement on the clinical definition or a generally accepted explanation. In line with observations from object agnosia and prosopagnosia, we hypothesised that (some of) these patients might still be able to process colour information at an implicit level. In this study, we investigated this possibility of implicit access to colour semantics and colour names in a man (MAH) who suffers from developmental colour agnosia. We designed two experimental computer tasks: an associative colour priming task with a lexical decision response and a reversed Stroop task. The results of these experiments suggest that there is indeed automatic processing of colour, although MAH was unable to explicitly use colour information.

  14. Viewing images of snakes accelerates making judgements of their colour in humans: red snake effect as an instance of ‘emotional Stroop facilitation’

    Science.gov (United States)

    Shibasaki, Masahiro; Isomura, Tomoko; Masataka, Nobuo

    2014-01-01

    One of the most prevalent current psychobiological notions about human behaviour and emotion suggests that prioritization of threatening stimuli processing induces deleterious effects on task performance. In order to confirm its relevancy, 108 adults and 25 children were required to name the colour of images of snakes and flowers, using the pictorial emotional Stroop paradigm. When reaction time to answer the colour of each stimulus was measured, its value was found to decrease when snake images were presented when compared with when flower images were presented. Thus, contrary to the expectation from previous emotional Stroop paradigm research, emotions evoked by viewing images of snakes as a biologically relevant threatening stimulus were found to be likely to exert a facilitating rather than interfering effect on making judgements of their colour. PMID:26064551

  15. Colour application on mammography image segmentation

    Science.gov (United States)

    Embong, R.; Aziz, N. M. Nik Ab.; Karim, A. H. Abd; Ibrahim, M. R.

    2017-09-01

    The segmentation process is one of the most important steps in image processing and computer vision since it is vital in the initial stage of image analysis. Segmentation of medical images involves complex structures and it requires precise segmentation result which is necessary for clinical diagnosis such as the detection of tumour, oedema, and necrotic tissues. Since mammography images are grayscale, researchers are looking at the effect of colour in the segmentation process of medical images. Colour is known to play a significant role in the perception of object boundaries in non-medical colour images. Processing colour images require handling more data, hence providing a richer description of objects in the scene. Colour images contain ten percent (10%) additional edge information as compared to their grayscale counterparts. Nevertheless, edge detection in colour image is more challenging than grayscale image as colour space is considered as a vector space. In this study, we implemented red, green, yellow, and blue colour maps to grayscale mammography images with the purpose of testing the effect of colours on the segmentation of abnormality regions in the mammography images. We applied the segmentation process using the Fuzzy C-means algorithm and evaluated the percentage of average relative error of area for each colour type. The results showed that all segmentation with the colour map can be done successfully even for blurred and noisy images. Also the size of the area of the abnormality region is reduced when compare to the segmentation area without the colour map. The green colour map segmentation produced the smallest percentage of average relative error (10.009%) while yellow colour map segmentation gave the largest percentage of relative error (11.367%).

  16. Experiments on the ectoparasitic deer ked that often attacks humans; preferences for body parts, colour and temperature.

    Science.gov (United States)

    Kortet, R; Härkönen, L; Hokkanen, P; Härkönen, S; Kaitala, A; Kaunisto, S; Laaksonen, S; Kekäläinen, J; Ylönen, H

    2010-06-01

    The deer ked (Lipoptena cervi) can fail in its host search. Host search fails when an individual deer ked irreversibly accepts a host unsuitable for its reproduction (e.g. a human) and drops its wings. In northern Europe, the main host of the deer ked is the moose (Alces alces). The deer ked is increasingly causing serious problems for humans (for example, causing deer ked dermatitis) and is considered a threat for the recreational use of forests. The adult deer ked flies in early and mid-autumn to search for a host. Our aims were: (i) to study whether there are ways to avoid deer ked attacks by wearing particular clothing, and (ii) to evaluate deer ked host choice. Using human targets, we explored the cues the deer ked uses for host selection. We studied which part of the host body deer keds target and if body colour and temperature affect their choice. In our experiments, deer keds landed more on dark and red clothing than on white clothing. Moreover, deer keds mostly attacked the upper body parts and preferred the back side of the body over the front side. Finally, deer keds preferred the warmest areas of the host.

  17. Visions of Transmodernity: A New Renaissance of our Human History?

    Directory of Open Access Journals (Sweden)

    Irena Ateljevic

    2013-06-01

    Full Text Available In this paper I will engage with a broad range of literature that provides us with many signals and evidence of an emerging and significant paradigm shift in human evolution. In doing so, I will offer the concept of transmodernity as an umbrella term that connotes the emerging socio-cultural, economic, political and philosophical shift. My research across boundaries of many different fields such as critical economics, philosophy, subaltern and postcolonial studies, social anthropology and psychology, cultural studies, political science and social activism literature will illustrate how an integrated approach and dialogue is urgently needed, indeed more than ever before. Different authors use a variety of terms to capture what can essentially be described as the synchronised phenomenon of emerging higher collective consciousness—transmodernity paradigm (Ghisi; transmodern philosophy of political liberation (Dussel; Hegelian dialectical triad of thesis, antithesis and synthesis (Magda; the reflective/living-systems paradigm (Elgin; the partnership model of caring economics (Eisler; the relational global consciousness of biosphere politics (Rifkin; love ethics (hooks; the circularity paradigm of interdependence (Steinem. With a reference to a variety of authors I will argue that the reason we do not hear much about this movement is because it is not centralised and coordinated under a single unifying name. ‘Transmodernity’ ropes together many concepts/tenets of other writings that do not necessarily use the same term, but I chose it in order to communicate the overall idea of the emerging paradigm shift as the next cultural and material development in human history. I have opted to use the concept as a medium to convey humanity’s unified synchronicity, which is part of a transformation that can be claimed to be ‘the new renaissance’ of human history.

  18. Human Vision System’s Region of Interest Based Video Coding

    Directory of Open Access Journals (Sweden)

    K. Asha

    2013-05-01

    Full Text Available While watching a video human visual system gives more attention on the foreground objects than background objects. That is to say, human vision system pays more attention to region of interest, such as the human faces in the video content. Most of the video encoders compress video by considering every part of the video frames with equal importance. So the video size could not be reduced to maintain quality. The proposed system can detect the foreground and it can allocate different bit rates for different regions. By doing this the video quality can be maintained and the size can be reduced up to 40%.

  19. A VISION OF QUANTIFICATION OF SUSTAINABLE HUMAN DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Neyda Ibáñez

    2015-07-01

    Full Text Available The present study aimed to propose new measurement components of sustainable human development based on the historical and theoretical development path. The research assumes ontoepistemological position based on positivism, addressing technical survey and instrument of written questionnaire administered to thirty-one (31 experts in the field of knowledge, and whose analysis allowed us to conclude that traditional models to measure development are insufficient to demonstrate the reality of nations. Therefore, the proposed measure is derived in seven components: ethical, spiritual and cultural addition to the formally established by Munasinghe (1993, 2011 and the UN (2012: economic, social, environmental, institutional constituted in total, by selecting one hundred fifty five (155 variables.

  20. Theoretical and practical exploration of vision building in human influenza pandemic prevention & control

    Institute of Scientific and Technical Information of China (English)

    PengKong; YanKong; XuJiang; XiaohuaWang

    2010-01-01

    This article introduced the vision building concept about human influenza pandemic prevention and control. Different visions were built by creating different shapes of building blocks which also represented different organizations and physical facilities, respectively. The around-view reflection is required to be developed in the process of building so as to search for the ideal pattern. The correlation of all sectors and systems are established to combine different kinds of things, from one family to another, from communities, towns, counties, cities, rural areas, provinces to the state to handle trivial problems. These training objectives have been successfully accomplished, which has not only enriched the knowledge about prevention and control of influenza pandemic between different departments but also clarified the roles and responsibility. It lays the firm foundation for next cooperation between different departments, and make a bridge for the objective and choice of channel over human influenza pandemic prevention and control.

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

    Science.gov (United States)

    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.

  2. The selectivity of responses to red-green colour and achromatic contrast in the human visual cortex: an fMRI adaptation study.

    Science.gov (United States)

    Mullen, Kathy T; Chang, Dorita H F; Hess, Robert F

    2015-12-01

    There is controversy as to how responses to colour in the human brain are organized within the visual pathways. A key issue is whether there are modular pathways that respond selectively to colour or whether there are common neural substrates for both colour and achromatic (Ach) contrast. We used functional magnetic resonance imaging (fMRI) adaptation to investigate the responses of early and extrastriate visual areas to colour and Ach contrast. High-contrast red-green (RG) and Ach sinewave rings (0.5 cycles/degree, 2 Hz) were used as both adapting stimuli and test stimuli in a block design. We found robust adaptation to RG or Ach contrast in all visual areas. Cross-adaptation between RG and Ach contrast occurred in all areas indicating the presence of integrated, colour and Ach responses. Notably, we revealed contrasting trends for the two test stimuli. For the RG test, unselective processing (robust adaptation to both RG and Ach contrast) was most evident in the early visual areas (V1 and V2), but selective responses, revealed as greater adaptation between the same stimuli than cross-adaptation between different stimuli, emerged in the ventral cortex, in V4 and VO in particular. For the Ach test, unselective responses were again most evident in early visual areas but Ach selectivity emerged in the dorsal cortex (V3a and hMT+). Our findings support a strong presence of integrated mechanisms for colour and Ach contrast across the visual hierarchy, with a progression towards selective processing in extrastriate visual areas. © 2015 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  3. Evidence against global attention filters selective for absolute bar-orientation in human vision.

    Science.gov (United States)

    Inverso, Matthew; Sun, Peng; Chubb, Charles; Wright, Charles E; Sperling, George

    2016-01-01

    The finding that an item of type A pops out from an array of distractors of type B typically is taken to support the inference that human vision contains a neural mechanism that is activated by items of type A but not by items of type B. Such a mechanism might be expected to yield a neural image in which items of type A produce high activation and items of type B low (or zero) activation. Access to such a neural image might further be expected to enable accurate estimation of the centroid of an ensemble of items of type A intermixed with to-be-ignored items of type B. Here, it is shown that as the number of items in stimulus displays is increased, performance in estimating the centroids of horizontal (vertical) items amid vertical (horizontal) distractors degrades much more quickly and dramatically than does performance in estimating the centroids of white (black) items among black (white) distractors. Together with previous findings, these results suggest that, although human vision does possess bottom-up neural mechanisms sensitive to abrupt local changes in bar-orientation, and although human vision does possess and utilize top-down global attention filters capable of selecting multiple items of one brightness or of one color from among others, it cannot use a top-down global attention filter capable of selecting multiple bars of a given absolute orientation and filtering bars of the opposite orientation in a centroid task.

  4. Mouse Simulation Using Two Coloured Tapes

    CERN Document Server

    Kumar, Vikram; Mahe, Swapnil; Vyawahare, Swapnil; 10.5121/ijist.2012.2206

    2012-01-01

    In this paper, we present a novel approach for Human Computer Interaction (HCI) where, we control cursor movement using a real-time camera. Current methods involve changing mouse parts such as adding more buttons or changing the position of the tracking ball. Instead, our method is to use a camera and computer vision technology, such as image segmentation and gesture recognition, to control mouse tasks (left and right clicking, double-clicking, and scrolling) and we show how it can perform everything as current mouse devices can. The software will be developed in JAVA language. Recognition and pose estimation in this system are user independent and robust as we will be using colour tapes on our finger to perform actions. The software can be used as an intuitive input interface to applications that require multi-dimensional control e.g. computer games etc.

  5. SPECTRAL AND SPATIAL SELECTIVITY OF LUMINANCE VISION IN REEF FISH

    Directory of Open Access Journals (Sweden)

    Ulrike E Siebeck

    2014-09-01

    Full Text Available Luminance vision has high spatial resolution and is used for form vision and texture discrimination. In humans, birds and bees luminance channel is spectrally selective – it depends on the signals of the long-wavelength sensitive photoreceptors (bees or on the sum of long- and middle- wavelength sensitive cones (humans, but not on the signal of the short-wavelength sensitive (blue photoreceptors. The reasons of such selectivity are not fully understood. The aim of this study is to reveal the inputs of cone signals to high resolution luminance vision in reef fish. 16 freshly caught damselfish, Pomacentrus amboinensis, were trained to discriminate stimuli differing either in their colour or in their fine patterns (stripes vs. cheques. Three colours (‘bright green’, ‘dark green’ and ‘blue’ were used to create two sets of colour and two sets of pattern stimuli. The ‘bright green’ and ‘dark green’ were similar in their chromatic properties for fish, but differed in their lightness; the ‘dark green’ differed from ‘blue’ in the signal for the blue cone, but yielded similar signals in the long-wavelength and middle-wavelength cones. Fish easily learned to discriminate ‘bright green’ from ‘dark green’ and ‘dark green’ from ‘blue’ stimuli. Fish also could discriminate the fine patterns created from ‘dark green’ and ‘bright green’. However, fish failed to discriminate fine patterns created from ‘blue’ and ‘dark green’ colours, i.e. the colours that provided contrast for the blue-sensitive photoreceptor, but not for the long-wavelength sensitive one. High resolution luminance vision in damselfish, Pomacentrus amboinensis, does not have input from the blue-sensitive cone, which may indicate that the spectral selectivity of luminance channel is a general feature of visual processing in both aquatic and terrestrial animals.

  6. Automatic human body modeling for vision-based motion capture system using B-spline parameterization of the silhouette

    Science.gov (United States)

    Jaume-i-Capó, Antoni; Varona, Javier; González-Hidalgo, Manuel; Mas, Ramon; Perales, Francisco J.

    2012-02-01

    Human motion capture has a wide variety of applications, and in vision-based motion capture systems a major issue is the human body model and its initialization. We present a computer vision algorithm for building a human body model skeleton in an automatic way. The algorithm is based on the analysis of the human shape. We decompose the body into its main parts by computing the curvature of a B-spline parameterization of the human contour. This algorithm has been applied in a context where the user is standing in front of a camera stereo pair. The process is completed after the user assumes a predefined initial posture so as to identify the main joints and construct the human model. Using this model, the initialization problem of a vision-based markerless motion capture system of the human body is solved.

  7. Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range.

    Directory of Open Access Journals (Sweden)

    Domicele Jonauskaite

    Full Text Available Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.

  8. EFFECTS OF FATLIQURING PROCESS ON LEATHERS COLOURED WITH IR REFLECTIVE DYES AND PIGMENTS

    Directory of Open Access Journals (Sweden)

    MUTLU Mehmet Mete

    2017-05-01

    Full Text Available Black coloured materials and consumer goods are known to be heating up more, because they absorb sun radiation more than light colours. This heating is a problem for the users for black automotive or motorcycle leathers and also for dark shoes and boots which are exposed to sun heat. Human vision system can distinguish visible colours between the wavelengths of 390-700 nm. So reflecting the sun radiation in the infrared area of radiation spectrum higher than 700nm, is a solution for heating problem without affecting the visible colour. For this reason IR reflective dyes and pigments are designed. A leading Leather Chemical Company has developed an IR reflecting dyeing system for leather keeping the dark coloured leathers cooler under sun radiation. Additionally in theory, fat and water content of leather affects its heating properties. In this study, effect of natural, synthetic and waterproof fatliquoring systems on heating properties of leathers coloured with IR reflective dyes and pigments are investigated.

  9. Plasmonic colour generation

    DEFF Research Database (Denmark)

    Kristensen, Anders; Yang, Joel K. W.; Bozhevolnyi, Sergey I.

    2016-01-01

    Plasmonic colours are structural colours that emerge from resonant interactions between light and metallic nanostructures. The engineering of plasmonic colours is a promising, rapidly emerging research field that could have a large technological impact. We highlight basic properties of plasmonic...

  10. An approach to integrate the human vision psychology and perception knowledge into image enhancement

    Science.gov (United States)

    Wang, Hui; Huang, Xifeng; Ping, Jiang

    2009-07-01

    Image enhancement is very important image preprocessing technology especially when the image is captured in the poor imaging condition or dealing with the high bits image. The benefactor of image enhancement either may be a human observer or a computer vision process performing some kind of higher-level image analysis, such as target detection or scene understanding. One of the main objects of the image enhancement is getting a high dynamic range image and a high contrast degree image for human perception or interpretation. So, it is very necessary to integrate either empirical or statistical human vision psychology and perception knowledge into image enhancement. The human vision psychology and perception claims that humans' perception and response to the intensity fluctuation δu of visual signals are weighted by the background stimulus u, instead of being plainly uniform. There are three main laws: Weber's law, Weber- Fechner's law and Stevens's Law that describe this phenomenon in the psychology and psychophysics. This paper will integrate these three laws of the human vision psychology and perception into a very popular image enhancement algorithm named Adaptive Plateau Equalization (APE). The experiments were done on the high bits star image captured in night scene and the infrared-red image both the static image and the video stream. For the jitter problem in the video stream, this algorithm reduces this problem using the difference between the current frame's plateau value and the previous frame's plateau value to correct the current frame's plateau value. Considering the random noise impacts, the pixel value mapping process is not only depending on the current pixel but the pixels in the window surround the current pixel. The window size is usually 3×3. The process results of this improved algorithms is evaluated by the entropy analysis and visual perception analysis. The experiments' result showed the improved APE algorithms improved the quality of the

  11. Colour Guided Colour Image Steganography

    CERN Document Server

    Amirtharajan, R; Swarup, Motamarri Abhilash; K, Mohamed Ashfaaq; Rayappan, John Bosco Balaguru

    2010-01-01

    Information security has become a cause of concern because of the electronic eavesdropping. Capacity, robustness and invisibility are important parameters in information hiding and are quite difficult to achieve in a single algorithm. This paper proposes a novel steganography technique for digital color image which achieves the purported targets. The professed methodology employs a complete random scheme for pixel selection and embedding of data. Of the three colour channels (Red, Green, Blue) in a given colour image, the least two significant bits of any one of the channels of the color image is used to channelize the embedding capacity of the remaining two channels. We have devised three approaches to achieve various levels of our desired targets. In the first approach, Red is the default guide but it results in localization of MSE in the remaining two channels, which makes it slightly vulnerable. In the second approach, user gets the liberty to select the guiding channel (Red, Green or Blue) to guide the r...

  12. Inverse Modeling of Human Knee Joint Based on Geometry and Vision Systems for Exoskeleton Applications

    Directory of Open Access Journals (Sweden)

    Eduardo Piña-Martínez

    2015-01-01

    Full Text Available Current trends in Robotics aim to close the gap that separates technology and humans, bringing novel robotic devices in order to improve human performance. Although robotic exoskeletons represent a breakthrough in mobility enhancement, there are design challenges related to the forces exerted to the users’ joints that result in severe injuries. This occurs due to the fact that most of the current developments consider the joints as noninvariant rotational axes. This paper proposes the use of commercial vision systems in order to perform biomimetic joint design for robotic exoskeletons. This work proposes a kinematic model based on irregular shaped cams as the joint mechanism that emulates the bone-to-bone joints in the human body. The paper follows a geometric approach for determining the location of the instantaneous center of rotation in order to design the cam contours. Furthermore, the use of a commercial vision system is proposed as the main measurement tool due to its noninvasive feature and for allowing subjects under measurement to move freely. The application of this method resulted in relevant information about the displacements of the instantaneous center of rotation at the human knee joint.

  13. Fractal coding of wavelet image based on human vision contrast-masking effect

    Science.gov (United States)

    Wei, Hai; Shen, Lansun

    2000-06-01

    In this paper, a fractal-based compression approach of wavelet image is presented. The scheme tries to make full use of the sensitivity features of the human visual system. With the wavelet-based multi-resolution representation of image, detail vectors of each high frequency sub-image are constructed in accordance with its spatial orientation in order to grasp the edge information to which human observer is sensitive. Then a multi-level selection algorithm based on human vision's contrast masking effect is proposed to make the decision whether a detail vector is coded or not. Those vectors below the contrast threshold are discarded without introducing visual artifacts because of the ignorance of human vision. As for the redundancy of the retained vectors, different fractal- based methods are employed to decrease the correlation in single sub-image and between the different resolution sub- images with the same orientation. Experimental results suggest the efficiency of the proposed scheme. With the standard test image, our approach outperforms the EZW algorithm and the JPEG method.

  14. Importance of non-synonymous OCA2 variants in human eye colour prediction

    DEFF Research Database (Denmark)

    Andersen, Jeppe Dyrberg; Pietroni, Carlotta; Johansen, Peter

    2016-01-01

    in the promotor region of OCA2 (OMIM #611409). Nevertheless, many eye colors cannot be explained by only considering rs12913832:A>G. Methods: In this study, we searched for additional variants in OCA2 to explain human eye color by sequencing a 500 kbp region, encompassing OCA2 and its promotor region. Results: We......Background: The color of the eyes is one of the most prominent phenotypes in humans and it is often used to describe the appearance of an individual. The intensity of pigmentation in the iris is strongly associated with one single-nucleotide polymorphism (SNP), rs12913832:A>G that is located...... identified three nonsynonymous OCA2 variants as important for eye color, including rs1800407:G>A (p.Arg419Gln) and two variants, rs74653330:A>T (p.Ala481Thr) and rs121918166:G>A (p.Val443Ile), not previously described as important for eye color variation. It was shown that estimated haplotypes consisting...

  15. Blobs versus bars: psychophysical evidence supports two types of orientation response in human color vision.

    Science.gov (United States)

    Gheiratmand, Mina; Meese, Tim S; Mullen, Kathy T

    2013-01-02

    The classic hypothesis of Livingstone and Hubel (1984, 1987) proposed two types of color pathways in primate visual cortex based on recordings from single cells: a segregated, modular pathway that signals color but provides little information about shape or form and a second pathway that signals color differences and so defines forms without the need to specify their colors. A major problem has been to reconcile this neurophysiological hypothesis with the behavioral data. A wealth of psychophysical studies has demonstrated that color vision has orientation-tuned responses and little impairment on form related tasks, but these have not revealed any direct evidence for nonoriented mechanisms. Here we use a psychophysical method of subthreshold summation across orthogonal orientations for isoluminant red-green gratings in monocular and dichoptic viewing conditions to differentiate between nonoriented and orientation-tuned responses to color contrast. We reveal nonoriented color responses at low spatial frequencies (0.25-0.375 c/deg) under monocular conditions changing to orientation-tuned responses at higher spatial frequencies (1.5 c/deg) and under binocular conditions. We suggest that two distinct pathways coexist in color vision at the behavioral level, revealed at different spatial scales: one is isotropic, monocular, and best equipped for the representation of surface color, and the other is orientation-tuned, binocular, and selective for shape and form. This advances our understanding of the organization of the neural pathways involved in human color vision and provides a strong link between neurophysiological and behavioral data.

  16. Developmental colour agnosia.

    Science.gov (United States)

    van Zandvoort, Martine J E; Nijboer, Tanja C W; de Haan, Edward

    2007-08-01

    Colour agnosia concerns the inability to recognise colours despite intact colour perception, semantic memory for colour information, and colour naming. Patients with selective colour agnosia have been described and the deficit is associated with left hemisphere damage. Here we report a case study of a 43-year-old man who was referred to us with a stroke in his right cerebellar hemisphere. During the standard assessment it transpired that he was unable to name coloured patches. Detailed assessment of his colour processing showed that he suffers from a selective colour agnosia. As he claimed to have had this problem all his life, and the fact that the infratentorial infarct that he had incurred was in an area far away from the brain structures that are known to be involved in colour processing, we suggest that he is the first reported case of developmental colour agnosia.

  17. Interactions between colour and synaesthetic colour: an effect of simultaneous colour contrast on synaesthetic colours.

    Science.gov (United States)

    Nijboer, Tanja C W; Gebuis, Titia; te Pas, Susan F; van der Smagt, Maarten J

    2011-01-01

    We investigated whether simultaneous colour contrast affects the synaesthetic colour experience and normal colour percept in a similar manner. We simultaneously presented a target stimulus (i.e. grapheme) and a reference stimulus (i.e. hash). Either the grapheme or the hash was presented on a saturated background of the same or opposite colour category as the synaesthetic colour and the other stimulus on a grey background. In both conditions, grapheme-colour synaesthetes were asked to colour the hash in a colour similar to the synaesthetic colour of the grapheme. Controls that were pair-matched to the synaesthetes performed the same experiment, but for them, the grapheme was presented in the colour induced by the grapheme in synaesthetes. When graphemes were presented on a grey and the hash on a coloured background, a traditional simultaneous colour-contrast effect was found for controls as well as synaesthetes. When graphemes were presented on colour and the hash on grey, the controls again showed a traditional simultaneous colour-contrast effect, whereas the synaesthetes showed the opposite effect. Our results show that synaesthetic colour experiences differ from normal colour perception; both are susceptible to different surrounding colours, but not in a comparable manner.

  18. Human vision, visual processing, and digital display; Proceedings of the Meeting, Los Angeles, CA, Jan. 18-20, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Rogowitz, B.E.

    1989-01-01

    Various papers on human vision, visual processing, and digital display are presented. The general topics considered include: physics and psychophysics of displayed information; visual performance and image quality; vision-based algorithms for image processing; visual sampling, compression, and representation; texture, pattern, and motion; color perception, coding, and representation. Some individual topics discussed are: respective fields and visual representations; psychophysical rating of image compression techniques; new paradigm for testing human and machine motion perception; motion perception model with interactions between spatial frequency channels; application of visual psychophysics to the design of video systems for use in space; unified model for human color perception and visual adaptation.

  19. Can colour be measured?

    DEFF Research Database (Denmark)

    Ramanujam, P.S.

    Colour is a sensation. While wavelength can be measured with a spectrometer consisting of dispersive elements and colour insensitive detectors, detection of colour is accomplished by the eye, equipped with a lens, colour sensitive detectors, and a powerful processor in the form of brain. Sometimes...

  20. Collaboration between human and nonhuman players in Night Vision Tactical Trainer-Shadow

    Science.gov (United States)

    Berglie, Stephen T.; Gallogly, James J.

    2016-05-01

    The Night Vision Tactical Trainer - Shadow (NVTT-S) is a U.S. Army-developed training tool designed to improve critical Manned-Unmanned Teaming (MUMT) communication skills for payload operators in Unmanned Aerial Sensor (UAS) crews. The trainer is composed of several Government Off-The-Shelf (GOTS) simulation components and takes the trainee through a series of escalating engagements using tactically relevant, realistically complex, scenarios involving a variety of manned, unmanned, aerial, and ground-based assets. The trainee is the only human player in the game and he must collaborate, from his web-based mock operating station, with various non-human players via spoken natural language over simulated radio in order to execute the training missions successfully. Non-human players are modeled in two complementary layers - OneSAF provides basic background behaviors for entities while NVTT provides higher level models that control entity actions based on intent extracted from the trainee's spoken natural dialog with game entities. Dialog structure is modeled based on Army standards for communication and verbal protocols. This paper presents an architecture that integrates the U.S. Army's Night Vision Image Generator (NVIG), One Semi- Automated Forces (OneSAF), a flight dynamics model, as well as Commercial Off The Shelf (COTS) speech recognition and text to speech products to effect an environment with sufficient entity counts and fidelity to enable meaningful teaching and reinforcement of critical communication skills. It further demonstrates the model dynamics and synchronization mechanisms employed to execute purpose-built training scenarios, and to achieve ad-hoc collaboration on-the-fly between human and non-human players in the simulated environment.

  1. A Vision-Based System for Intelligent Monitoring: Human Behaviour Analysis and Privacy by Context

    Directory of Open Access Journals (Sweden)

    Alexandros Andre Chaaraoui

    2014-05-01

    Full Text Available Due to progress and demographic change, society is facing a crucial challenge related to increased life expectancy and a higher number of people in situations of dependency. As a consequence, there exists a significant demand for support systems for personal autonomy. This article outlines the vision@home project, whose goal is to extend independent living at home for elderly and impaired people, providing care and safety services by means of vision-based monitoring. Different kinds of ambient-assisted living services are supported, from the detection of home accidents, to telecare services. In this contribution, the specification of the system is presented, and novel contributions are made regarding human behaviour analysis and privacy protection. By means of a multi-view setup of cameras, people’s behaviour is recognised based on human action recognition. For this purpose, a weighted feature fusion scheme is proposed to learn from multiple views. In order to protect the right to privacy of the inhabitants when a remote connection occurs, a privacy-by-context method is proposed. The experimental results of the behaviour recognition method show an outstanding performance, as well as support for multi-view scenarios and real-time execution, which are required in order to provide the proposed services.

  2. Human detection from a mobile robot using fusion of laser and vision information.

    Science.gov (United States)

    Fotiadis, Efstathios P; Garzón, Mario; Barrientos, Antonio

    2013-09-04

    This paper presents a human detection system that can be employed on board a mobile platform for use in autonomous surveillance of large outdoor infrastructures. The prediction is based on the fusion of two detection modules, one for the laser and another for the vision data. In the laser module, a novel feature set that better encapsulates variations due to noise, distance and human pose is proposed. This enhances the generalization of the system, while at the same time, increasing the outdoor performance in comparison with current methods. The vision module uses the combination of the histogram of oriented gradients descriptor and the linear support vector machine classifier. Current approaches use a fixed-size projection to define regions of interest on the image data using the range information from the laser range finder. When applied to small size unmanned ground vehicles, these techniques suffer from misalignment, due to platform vibrations and terrain irregularities. This is effectively addressed in this work by using a novel adaptive projection technique, which is based on a probabilistic formulation of the classifier performance. Finally, a probability calibration step is introduced in order to optimally fuse the information from both modules. Experiments in real world environments demonstrate the robustness of the proposed method.

  3. Human Detection from a Mobile Robot Using Fusion of Laser and Vision Information

    Directory of Open Access Journals (Sweden)

    Antonio Barrientos

    2013-09-01

    Full Text Available This paper presents a human detection system that can be employed on board a mobile platform for use in autonomous surveillance of large outdoor infrastructures. The prediction is based on the fusion of two detection modules, one for the laser and another for the vision data. In the laser module, a novel feature set that better encapsulates variations due to noise, distance and human pose is proposed. This enhances the generalization of the system, while at the same time, increasing the outdoor performance in comparison with current methods. The vision module uses the combination of the histogram of oriented gradients descriptor and the linear support vector machine classifier. Current approaches use a fixed-size projection to define regions of interest on the image data using the range information from the laser range finder. When applied to small size unmanned ground vehicles, these techniques suffer from misalignment, due to platform vibrations and terrain irregularities. This is effectively addressed in this work by using a novel adaptive projection technique, which is based on a probabilistic formulation of the classifier performance. Finally, a probability calibration step is introduced in order to optimally fuse the information from both modules. Experiments in real world environments demonstrate the robustness of the proposed method.

  4. Machine Vision Handbook

    CERN Document Server

    2012-01-01

    The automation of visual inspection is becoming more and more important in modern industry as a consistent, reliable means of judging the quality of raw materials and manufactured goods . The Machine Vision Handbook  equips the reader with the practical details required to engineer integrated mechanical-optical-electronic-software systems. Machine vision is first set in the context of basic information on light, natural vision, colour sensing and optics. The physical apparatus required for mechanized image capture – lenses, cameras, scanners and light sources – are discussed followed by detailed treatment of various image-processing methods including an introduction to the QT image processing system. QT is unique to this book, and provides an example of a practical machine vision system along with extensive libraries of useful commands, functions and images which can be implemented by the reader. The main text of the book is completed by studies of a wide variety of applications of machine vision in insp...

  5. Colour Vision: Random Retina of Butterflies Explained.

    Science.gov (United States)

    Kelber, Almut

    2016-10-10

    Butterfly eyes are random mosaics built of three ommatidia types, each with a different set of photoreceptors and pigments. What defines the combined features in each ommatidium? A new study has solved the puzzle.

  6. Application of digital human modeling and simulation for vision analysis of pilots in a jet aircraft: a case study.

    Science.gov (United States)

    Karmakar, Sougata; Pal, Madhu Sudan; Majumdar, Deepti; Majumdar, Dhurjati

    2012-01-01

    Ergonomic evaluation of visual demands becomes crucial for the operators/users when rapid decision making is needed under extreme time constraint like navigation task of jet aircraft. Research reported here comprises ergonomic evaluation of pilot's vision in a jet aircraft in virtual environment to demonstrate how vision analysis tools of digital human modeling software can be used effectively for such study. Three (03) dynamic digital pilot models, representative of smallest, average and largest Indian pilot population were generated from anthropometric database and interfaced with digital prototype of the cockpit in Jack software for analysis of vision within and outside the cockpit. Vision analysis tools like view cones, eye view windows, blind spot area, obscuration zone, reflection zone etc. were employed during evaluation of visual fields. Vision analysis tool was also used for studying kinematic changes of pilot's body joints during simulated gazing activity. From present study, it can be concluded that vision analysis tool of digital human modeling software was found very effective in evaluation of position and alignment of different displays and controls in the workstation based upon their priorities within the visual fields and anthropometry of the targeted users, long before the development of its physical prototype.

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

    Directory of Open Access Journals (Sweden)

    Adrian Horridge

    Full Text Available 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.

  8. Tetrachromacy, oil droplets and bird plumage colours.

    Science.gov (United States)

    Vorobyev, M; Osorio, D; Bennett, A T; Marshall, N J; Cuthill, I C

    1998-11-01

    There is a growing body of data on avian eyes, including measurements of visual pigment and oil droplet spectral absorption, and of receptor densities and their distributions across the retina. These data are sufficient to predict psychophysical colour discrimination thresholds for light-adapted eyes, and hence provide a basis for relating eye design to visual needs. We examine the advantages of coloured oil droplets, UV vision and tetrachromacy for discriminating a diverse set of avian plumage spectra under natural illumination. Discriminability is enhanced both by tetrachromacy and coloured oil droplets. Oil droplets may also improve colour constancy. Comparison of the performance of a pigeon's eye, where the shortest wavelength receptor peak is at 410 nm, with that of the passerine Leiothrix, where the ultraviolet-sensitive peak is at 365 nm, generally shows a small advantage to the latter, but this advantage depends critically on the noise level in the sensitivity mechanism and on the set of spectra being viewed.

  9. A vision and strategy for the virtual physiological human: 2012 update.

    Science.gov (United States)

    Hunter, Peter; Chapman, Tara; Coveney, Peter V; de Bono, Bernard; Diaz, Vanessa; Fenner, John; Frangi, Alejandro F; Harris, Peter; Hose, Rod; Kohl, Peter; Lawford, Pat; McCormack, Keith; Mendes, Miriam; Omholt, Stig; Quarteroni, Alfio; Shublaq, Nour; Skår, John; Stroetmann, Karl; Tegner, Jesper; Thomas, S Randall; Tollis, Ioannis; Tsamardinos, Ioannis; van Beek, Johannes H G M; Viceconti, Marco

    2013-04-06

    European funding under Framework 7 (FP7) for the virtual physiological human (VPH) project has been in place now for 5 years. The VPH Network of Excellence (NoE) has been set up to help develop common standards, open source software, freely accessible data and model repositories, and various training and dissemination activities for the project. It is also working to coordinate the many clinically targeted projects that have been funded under the FP7 calls. An initial vision for the VPH was defined by the FP6 STEP project in 2006. In 2010, we wrote an assessment of the accomplishments of the first two years of the VPH in which we considered the biomedical science, healthcare and information and communications technology challenges facing the project (Hunter et al. 2010 Phil. Trans. R. Soc. A 368, 2595-2614 (doi:10.1098/rsta.2010.0048)). We proposed that a not-for-profit professional umbrella organization, the VPH Institute, should be established as a means of sustaining the VPH vision beyond the time-frame of the NoE. Here, we update and extend this assessment and in particular address the following issues raised in response to Hunter et al.: (i) a vision for the VPH updated in the light of progress made so far, (ii) biomedical science and healthcare challenges that the VPH initiative can address while also providing innovation opportunities for the European industry, and (iii) external changes needed in regulatory policy and business models to realize the full potential that the VPH has to offer to industry, clinics and society generally.

  10. Low Vision

    Science.gov (United States)

    ... HHS USAJobs Home > Statistics and Data > Low Vision Low Vision Low Vision Defined: Low Vision is defined as the ... Ethnicity 2010 U.S. Age-Specific Prevalence Rates for Low Vision by Age, and Race/Ethnicity Table for ...

  11. Coloured Petri Nets

    DEFF Research Database (Denmark)

    Jensen, Kurt

    1991-01-01

    This paper describes how Coloured Petri Nets (CP-nets) have been developed — from being a promising theoretical model to being a full-fledged language for the design, specification, simulation, validation and implementation of large software systems (and other systems in which human beings and...... use of CP-nets — because it means that the function representation and the translations (which are a bit mathematically complex) no longer are parts of the basic definition of CP-nets. Instead they are parts of the invariant method (which anyway demands considerable mathematical skills...

  12. Human resource development for Vision 2020 in developing countries: a change from absolute numbers.

    Science.gov (United States)

    Adepoju, Feyi G; Ayanniyi, Abdulkabir A; Pam, Victoria; Akanbi, Toyin B

    2011-01-01

    To critically review the numbers, distribution, staff mix, and productivity of eye care workers (ECW) in Kwara State, north central Nigeria. A cross-sectional descriptive survey of all ECW identified from all eye care facilities in July 2008 was carried out using a structured questionnaire. Output data on cataract surgery of each institution were also collected and data analyzed using SPSS 16. A total of 157 ECW comprising 8 ophthalmologists, 4 diplomates, 16 residents training ophthalmologists, 96 mid-level ophthalmic personnel (67 ophthalmic nurses, 3 optometrists, and 26 others), and 33 administrative and supporting staff were available to a population of 2.37 million. Ophthalmologist to population ratio was 1:300,000, optometrist 1:790,000, and ophthalmic nurses 1:35,000. Eighty percent of ECW and institutions are located in the state capital. There were no orthoptists, low vision specialists, counselors, or cataract finders, while optometrists, managers, and primary ECW were inadequate. The staff mix was 1 surgeon to 12 other ECW and an average of 182 cataract surgeries per surgeon per year. Emphasis should shift to team building and ensuring available workers perform optimally rather than meeting the absolute numbers of some cadre, which does not guarantee improved output. Issues of equitable distribution, appropriate staff mix, filling identified gaps in human resources, and addressing poor service uptake should be the focus to reach the goals of Vision 2020: The Right to Sight.

  13. Recolouring-resistant colourings

    DEFF Research Database (Denmark)

    Pedersen, A. S.; Rautenbach, D.

    2011-01-01

    We study colourings of graphs with the property that the number of used colours cannot be reduced by applying some recolouring operation. A well-studied example of such colourings are b-colourings, which were introduced by Irving and Manlove [R.W. Irving, D.F. Manlove, The la-chromatic number...... of a graph, Discrete Appl. Math. 91 (1999) 127-141]. Given a graph and a colouring, a recolouring operation specifies a set of vertices of the graph on which the colouring can be changed. We consider two such operations: One which allows the recolouring of all vertices within some given distance of some...

  14. Global skin colour prediction from DNA

    NARCIS (Netherlands)

    S. Walsh (Susan); L.C. Chaitanya (Lakshmi); Breslin, K. (Krystal); Muralidharan, C. (Charanya); Bronikowska, A. (Agnieszka); E. Pośpiech (Ewelina); Koller, J. (Julia); L. Kovatsi (Leda); A. Wollstein (Andreas); W. Branicki (Wojciech); F. Liu; M.H. Kayser (Manfred)

    2017-01-01

    textabstractHuman skin colour is highly heritable and externally visible with relevance in medical, forensic, and anthropological genetics. Although eye and hair colour can already be predicted with high accuracies from small sets of carefully selected DNA markers, knowledge about the genetic

  15. Thermal vision based intelligent system for human detection and tracking in mobile robot control system

    Directory of Open Access Journals (Sweden)

    Ćirić Ivan T.

    2016-01-01

    Full Text Available This paper presents the results of the authors in thermal vision based mobile robot control. The most important segment of the high level control loop of mobile robot platform is an intelligent real-time algorithm for human detection and tracking. Temperature variations across same objects, air flow with different temperature gradients, reflections, person overlap while crossing each other, and many other non-linearities, uncertainty and noise, put challenges in thermal image processing and therefore the need of computationally intelligent algorithms for obtaining the efficient performance from human motion tracking system. The main goal was to enable mobile robot platform or any technical system to recognize the person in indoor environment, localize it and track it with accuracy high enough to allow adequate human-machine interaction. The developed computationally intelligent algorithms enables robust and reliable human detection and tracking based on neural network classifier and autoregressive neural network for time series prediction. Intelligent algorithm used for thermal image segmentation gives accurate inputs for classification. [Projekat Ministarstva nauke Republike Srbije, br. TR35005

  16. On the Use of Machine Vision Techniques to Detect Human Settlements in Satellite Images

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, C; Sengupta, S K; Poland, D; Futterman, J A H

    2003-01-10

    The automated production of maps of human settlement from recent satellite images is essential to studies of urbanization, population movement, and the like. The spectral and spatial resolution of such imagery is often high enough to successfully apply computer vision techniques. However, vast amounts of data have to be processed quickly. In this paper, we propose an approach that processes the data in several different stages. At each stage, using features appropriate to that stage, we identify the portion of the data likely to contain information relevant to the identification of human settlements. This data is used as input to the next stage of processing. Since the size of the data has reduced, we can now use more complex features in this next stage. These features can be more representative of human settlements, and also more time consuming to extract from the image data. Such a hierarchical approach enables us to process large amounts of data in a reasonable time, while maintaining the accuracy of human settlement identification. We illustrate our multi-stage approach using IKONOS 4-band and panchromatic images, and compare it with the straight-forward processing of the entire image.

  17. Reaction time as a measure of binocular interaction in human vision.

    Science.gov (United States)

    Blake, R; Martens, W; Di Gianfilippo, A

    1980-08-01

    In a series of psychophysical experiments monocular and binocular reaction times (RTs) were measured in response to the presentation of sinusoidal grating patterns. Over a wide range of contrast values, binocular RT was consistently faster than monocular RT, even at high-contrast levels where RT had reached asymptotic levels. For observers with good stereopsis this binocular summation effect was greater than that expected on the basis of probability summation alone, whereas observers with deficient stereopsis performed at the level of probability summation. For normal observers broadband random noise presented to one eye produced an elevation in RT to gratings presented to the other eye; no such dichoptic masking effect was found in a stereoblind observer. These results validate the use of RT as an efficient, reliable measure of binocular interaction in human vision.

  18. Blindsight and Unconscious Vision: What They Teach Us about the Human Visual System.

    Science.gov (United States)

    Ajina, Sara; Bridge, Holly

    2016-10-23

    Damage to the primary visual cortex removes the major input from the eyes to the brain, causing significant visual loss as patients are unable to perceive the side of the world contralateral to the damage. Some patients, however, retain the ability to detect visual information within this blind region; this is known as blindsight. By studying the visual pathways that underlie this residual vision in patients, we can uncover additional aspects of the human visual system that likely contribute to normal visual function but cannot be revealed under physiological conditions. In this review, we discuss the residual abilities and neural activity that have been described in blindsight and the implications of these findings for understanding the intact system.

  19. Effects of Different Zernike Terms on Optical Quality and Vision of Human Eyes

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hao-Xin; XU Bing; LI Jing; DAI Yun; YU Xiang; ZHANG Yu-Dong; JIANG Wen-Han

    2009-01-01

    The visual quality of human eyes is much restricted by high-order aberrations as well as low-order aberrations (defocus and astigmatism), but each term of high-order aberrations contributes differently. The visual acuity and contrast of the image on the retina can be gained by inducing aberrations to each term of high orders. Based on an adaptive optics system, the visual acuity of four subjects is tested by inducing aberrations to each Zernike term after correcting all the aberrations of the subjects. Zernike terms near the center of the Zernike tree affect visual quality more than those near the edge both theoretically and experimentally, and 0.1-μm aberration of these terms can clearly degrade the optical quality and vision. The results suggest that correcting the terms near the center of Zernike tree can improve the visual quality effectively in practice.

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

    Science.gov (United States)

    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

  1. Coloured Hopf algebras

    CERN Document Server

    Quesne, C

    1997-01-01

    Quite recently, a ``coloured'' extension of the Yang-Baxter equation has appeared in the literature and various solutions of it have been proposed. In the present contribution, we introduce a generalization of Hopf algebras, to be referred to as coloured Hopf algebras, wherein the comultiplication, counit, and antipode maps are labelled by some colour parameters. The latter may take values in any finite, countably infinite, or uncountably infinite set. A straightforward extension of the quasitriangularity property involves a coloured universal ${\\cal R}$-matrix, satisfying the coloured Yang-Baxter equation. We show how coloured Hopf algebras can be constructed from standard ones by using an algebra isomorphism group, called colour group. Finally, we present two examples of coloured quantum universal enveloping algebras.

  2. Feedforward Object-Vision Models Only Tolerate Small Image Variations Compared to Human

    Directory of Open Access Journals (Sweden)

    Masoud eGhodrati

    2014-07-01

    Full Text Available Invariant object recognition is a remarkable ability of primates' visual system that its underlying mechanism has constantly been under intense investigations. Computational modelling is a valuable tool toward understanding the processes involved in invariant object recognition. Although recent computational models have shown outstanding performances on challenging image databases, they fail to perform well when images with more complex variations of the same object are applied to them. Studies have shown that making sparse representation of objects by extracting more informative visual features through a feedforward sweep can lead to higher recognition performances. Here, however, we show that when the complexity of image variations is high, even this approach results in poor performance compared to humans. To assess the performance of models and humans in invariant object recognition tasks, we built a parametrically controlled image database consisting of several object categories varied in different dimensions and levels, rendered from 3D planes. Comparing the performance of several object recognition models with human observers shows that only in low-level image variations the models perform similar to humans in categorization tasks. Furthermore, the results of our behavioral experiments demonstrate that, even under difficult experimental conditions (i.e. briefly presented masked stimuli with complex image variations, human observers performed outstandingly well, suggesting that the models are still far from resembling humans in invariant object recognition. Taken together, we suggest that learning sparse informative visual features, although desirable, is not a complete solution for future progresses in object-vision modelling. We show that this approach is not of significant help in solving the computational crux of object recognition (that is invariant object recognition when the identity-preserving image variations become more complex.

  3. Accurate representation of interference colours (Michel-Lévy chart): from rendering to image colour correction.

    Science.gov (United States)

    Linge Johnsen, S A; Bollmann, J; Lee, H W; Zhou, Y

    2017-09-21

    Here a work flow towards an accurate representation of interference colours (Michel-Lévy chart) digitally captured on a polarised light microscope using dry and oil immersion objectives is presented. The work flow includes accurate rendering of interference colours considering the colour temperature of the light source of the microscope and chromatic adaptation to white points of RGB colour spaces as well as the colour correction of the camera using readily available colour targets. The quality of different colour correction profiles was tested independently on an IT8.7/1 target. The best performing profile was using the XYZ cLUT algorithm and it revealed a ΔE00 of 1.9 (6.4 no profile) at 5× and 1.1 (8.4 no profile) at 100× magnification, respectively. The overall performance of the workflow was tested by comparing rendered interference colours with colour-corrected images of a quartz wedge captured over a retardation range from 80-2500 nm at 5× magnification. Uncorrected images of the quartz wedge in sRGB colour space revealed a mean ΔE00 of 12.3, which could be reduced to a mean of 4.9 by applying a camera correction profile based on an IT8.7/1 target and the Matrix only algorithm (ΔE00 < 1.0 signifies colour differences imperceptible by the human eye). ΔE00 varied significantly over the retardation range of 80-2500 nm of the quartz wedge, but the reasons for this variation is not well understood and the quality of colour correction might be further improved in future by using custom made colour targets specifically designed for the analysis of high-order interference colours. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  4. Practical colour management

    Science.gov (United States)

    Williams, Susan

    2006-06-01

    Spectrophotometers have been successfully used for colour measurement. This paper addresses digital imaging as a complementary and alternative method of colour measurement and appearance and an effective communication tool as part of a practical colour management programme within the supply chain of a textile retailer. The specific needs—to measure and communicate textured dyed material and printed fabric—are discussed, as well as the colour specification and quality control (QC) of currently un-measurable fabrics and accessories. A unique method of using digital imaging for the assessment of colour fastness will also be discussed.

  5. Minimum Perceptible Differences in the Colour Reproduction of Photographic Prints.

    Science.gov (United States)

    Wood, Carol Ann

    Available from UMI in association with The British Library. Electronic simulations of the Macbeth Color Checker Chart were prepared such that each of the eighteen colour patches could be varied independently from the rest of the chart. The output was in the form of photographic colour prints which comprised a ring-around set of 168 prints for each of the colour patches, where each print was a colour perturbation from a standard print. Twelve observers, with normal colour vision, judged the prints in each set to be perceptibly different or not perceptibly different from the standard print, for each patch. The experimental results, in the form of hue-orientated and non hue-orientated ellipses, were compared with MacAdam type ellipses, CIELAB unit ellipses and ellipses derived from the CMC(1:c) colour difference formula: the comparisons were made in the 1976 CIELAB colour space. Colour reproduction indices were calculated for the end points of the semi-major and semi-minor axes of the CMC ellipses, for each of the eighteen colour patches. The coefficient of variation was very small for the combined hue index, the combined chroma index and the overall combined index, indicating that the mean values for these indices could be assigned to any of the ellipses as a measure of the minimum perceptible difference in terms of colour appearance.

  6. A Vision for the Exploration of Mars: Robotic Precursors Followed by Humans to Mars Orbit in 2033

    Science.gov (United States)

    Sellers, Piers J.; Garvin, James B.; Kinney, Anne L.; Amato, Michael J.; White, Nicholas E.

    2012-01-01

    The reformulation of the Mars program gives NASA a rare opportunity to deliver a credible vision in which humans, robots, and advancements in information technology combine to open the deep space frontier to Mars. There is a broad challenge in the reformulation of the Mars exploration program that truly sets the stage for: 'a strategic collaboration between the Science Mission Directorate (SMD), the Human Exploration and Operations Mission Directorate (HEOMD) and the Office of the Chief Technologist, for the next several decades of exploring Mars'.Any strategy that links all three challenge areas listed into a true long term strategic program necessitates discussion. NASA's SMD and HEOMD should accept the President's challenge and vision by developing an integrated program that will enable a human expedition to Mars orbit in 2033 with the goal of returning samples suitable for addressing the question of whether life exists or ever existed on Mars

  7. Rockpool gobies change colour for camouflage.

    Directory of Open Access Journals (Sweden)

    Martin Stevens

    Full Text Available 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.

  8. The Elementary Operations of Human Vision Are Not Reducible to Template-Matching.

    Directory of Open Access Journals (Sweden)

    Peter Neri

    2015-11-01

    Full Text Available It is generally acknowledged that biological vision presents nonlinear characteristics, yet linear filtering accounts of visual processing are ubiquitous. The template-matching operation implemented by the linear-nonlinear cascade (linear filter followed by static nonlinearity is the most widely adopted computational tool in systems neuroscience. This simple model achieves remarkable explanatory power while retaining analytical tractability, potentially extending its reach to a wide range of systems and levels in sensory processing. The extent of its applicability to human behaviour, however, remains unclear. Because sensory stimuli possess multiple attributes (e.g. position, orientation, size, the issue of applicability may be asked by considering each attribute one at a time in relation to a family of linear-nonlinear models, or by considering all attributes collectively in relation to a specified implementation of the linear-nonlinear cascade. We demonstrate that human visual processing can operate under conditions that are indistinguishable from linear-nonlinear transduction with respect to substantially different stimulus attributes of a uniquely specified target signal with associated behavioural task. However, no specific implementation of a linear-nonlinear cascade is able to account for the entire collection of results across attributes; a satisfactory account at this level requires the introduction of a small gain-control circuit, resulting in a model that no longer belongs to the linear-nonlinear family. Our results inform and constrain efforts at obtaining and interpreting comprehensive characterizations of the human sensory process by demonstrating its inescapably nonlinear nature, even under conditions that have been painstakingly fine-tuned to facilitate template-matching behaviour and to produce results that, at some level of inspection, do conform to linear filtering predictions. They also suggest that compliance with linear

  9. Colour Perception on Facial Expression towards Emotion

    Directory of Open Access Journals (Sweden)

    Rubita Sudirman

    2012-12-01

    Full Text Available This study is to investigate human perceptions on pairing of facial expressions of emotion with colours. A group of 27 subjects consisting mainly of younger and Malaysian had participated in this study. For each of the seven faces, which expresses the basic emotions neutral, happiness, surprise, anger, disgust, fear and sadness, a single colour is chosen from the eight basic colours for the match of best visual look to the face accordingly. The different emotions appear well characterized by a single colour. The approaches used in this experiment for analysis are psychology disciplines and colours engineering. These seven emotions are being matched by the subjects with their perceptions and feeling. Then, 12 male and 12 female data are randomly chosen from among the previous data to make a colour perception comparison between genders. The successes or failures in running of this test depend on the possibility of subjects to propose their every single colour for each expression. The result will translate into number and percentage as a guide for colours designers and psychology field.

  10. A vision-based fall detection algorithm of human in indoor environment

    Science.gov (United States)

    Liu, Hao; Guo, Yongcai

    2017-02-01

    Elderly care becomes more and more prominent in China as the population is aging fast and the number of aging population is large. Falls, as one of the biggest challenges in elderly guardianship system, have a serious impact on both physical health and mental health of the aged. Based on feature descriptors, such as aspect ratio of human silhouette, velocity of mass center, moving distance of head and angle of the ultimate posture, a novel vision-based fall detection method was proposed in this paper. A fast median method of background modeling with three frames was also suggested. Compared with the conventional bounding box and ellipse method, the novel fall detection technique is not only applicable for recognizing the fall behaviors end of lying down but also suitable for detecting the fall behaviors end of kneeling down and sitting down. In addition, numerous experiment results showed that the method had a good performance in recognition accuracy on the premise of not adding the cost of time.

  11. Vision-based interaction

    CERN Document Server

    Turk, Matthew

    2013-01-01

    In its early years, the field of computer vision was largely motivated by researchers seeking computational models of biological vision and solutions to practical problems in manufacturing, defense, and medicine. For the past two decades or so, there has been an increasing interest in computer vision as an input modality in the context of human-computer interaction. Such vision-based interaction can endow interactive systems with visual capabilities similar to those important to human-human interaction, in order to perceive non-verbal cues and incorporate this information in applications such

  12. A colour image reproduction framework for 3D colour printing

    Science.gov (United States)

    Xiao, Kaida; Sohiab, Ali; Sun, Pei-li; Yates, Julian M.; Li, Changjun; Wuerger, Sophie

    2016-10-01

    In this paper, the current technologies in full colour 3D printing technology were introduced. A framework of colour image reproduction process for 3D colour printing is proposed. A special focus was put on colour management for 3D printed objects. Two approaches, colorimetric colour reproduction and spectral based colour reproduction are proposed in order to faithfully reproduce colours in 3D objects. Two key studies, colour reproduction for soft tissue prostheses and colour uniformity correction across different orientations are described subsequently. Results are clear shown that applying proposed colour image reproduction framework, performance of colour reproduction can be significantly enhanced. With post colour corrections, a further improvement in colour process are achieved for 3D printed objects.

  13. Dynamic plasmonic colour display

    Science.gov (United States)

    Duan, Xiaoyang; Kamin, Simon; Liu, Na

    2017-02-01

    Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications.

  14. Topographical coloured plasmonic coins

    CERN Document Server

    Guay, Jean-Michel; Côté, Guillaume; Charron, Martin; Ramunno, Lora; Berini, Pierre; Weck, Arnaud

    2016-01-01

    The use of metal nanostructures for colourization has attracted a great deal of interest with the recent developments in plasmonics. However, the current top-down colourization methods based on plasmonic concepts are tedious and time consuming, and thus unviable for large-scale industrial applications. Here we show a bottom-up approach where, upon picosecond laser exposure, a full colour palette independent of viewing angle can be created on noble metals. We show that colours are related to a single laser processing parameter, the total accumulated fluence, which makes this process suitable for high throughput industrial applications. Statistical image analyses of the laser irradiated surfaces reveal various distributions of nanoparticle sizes which control colour. Quantitative comparisons between experiments and large-scale finite-difference time-domain computations, demonstrate that colours are produced by selective absorption phenomena in heterogeneous nanoclusters. Plasmonic cluster resonances are thus fo...

  15. 色彩,景观的外衣%COLOUR IN LANDSCAPE

    Institute of Scientific and Technical Information of China (English)

    宋文雯

    2015-01-01

    Colour is a vital element for human vision and affect life every moment. Colour research is a multidisciolinary work that combines physics, chemistry, psychology, art, etc. In the same way, landscape research consists of geography, biosphere, social culture, environment, architecture, ecology, aesthetics and philosophy, etc. Particularly, colour affect us like colour psychology, colour meaning, colour association and clour emotion. The relationship and effect are closely linked with landscape assessment.%色彩,作为人类第一视觉元素,无处不在地作用于人类的生活,同时更是所有设计领域的最前沿因素。色彩研究是跨学科的研究,融合了物理学、生理学、心理学、化学、艺术学等领域。同样,由地理学、生态学、地理科学和人文哲学共同建设形成的景观研究,包含了地形地貌、生态环境、风景园林、建筑、人文、视觉美学等多个方面。其中,色彩本身以及色彩的和谐对于景观视觉审美体现的重要性,以及景观色彩对人心理、生理的影响,都最终与景观的视觉评价息息相关。

  16. Training or inheritance in human vision: a critical test for understanding and engineering of intelligent optical systems

    Science.gov (United States)

    Lauinger, Norbert

    1997-09-01

    Inheritance or training in human vision? Training allows individual adaptation to environmental conditions, while genetics determine optimized constant i.e. long-term abilities. The biological engineering of the human eye needs both inheritance and training to realize its high performances. Particularly during postnatal training of an eye, adaptive freedom is necessary and available. To test the part of training it would become necessary to experimentally determine the in vivo refractive index differences between cellular nuclei and cytoplasm in retinal nuclear layers before and after birth to see if diffractive optical tuning of trichromatism in a retinal 3D-grating is synchronized with the differentiation of 3 photopigments in photopic vision or if the specialization in photochemistry depends on crystal- optical preprocessing.

  17. Investigating the mechanisms of hallucinogen-induced visions using 3,4-methylenedioxyamphetamine (MDA: a randomized controlled trial in humans.

    Directory of Open Access Journals (Sweden)

    Matthew J Baggott

    Full Text Available BACKGROUND: The mechanisms of drug-induced visions are poorly understood. Very few serotonergic hallucinogens have been studied in humans in decades, despite widespread use of these drugs and potential relevance of their mechanisms to hallucinations occurring in psychiatric and neurological disorders. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the mechanisms of hallucinogen-induced visions by measuring the visual and perceptual effects of the hallucinogenic serotonin 5-HT2AR receptor agonist and monoamine releaser, 3,4-methylenedioxyamphetamine (MDA, in a double-blind placebo-controlled study. We found that MDA increased self-report measures of mystical-type experience and other hallucinogen-like effects, including reported visual alterations. MDA produced a significant increase in closed-eye visions (CEVs, with considerable individual variation. Magnitude of CEVs after MDA was associated with lower performance on measures of contour integration and object recognition. CONCLUSIONS/SIGNIFICANCE: Drug-induced visions may have greater intensity in people with poor sensory or perceptual processing, suggesting common mechanisms with other hallucinatory syndromes. MDA is a potential tool to investigate mystical experiences and visual perception. TRIAL REGISTRATION: Clinicaltrials.gov NCT00823407.

  18. Human gene therapy for RPE65 isomerase deficiency activates the retinoid cycle of vision but with slow rod kinetics.

    Science.gov (United States)

    Cideciyan, Artur V; Aleman, Tomas S; Boye, Sanford L; Schwartz, Sharon B; Kaushal, Shalesh; Roman, Alejandro J; Pang, Ji-Jing; Sumaroka, Alexander; Windsor, Elizabeth A M; Wilson, James M; Flotte, Terence R; Fishman, Gerald A; Heon, Elise; Stone, Edwin M; Byrne, Barry J; Jacobson, Samuel G; Hauswirth, William W

    2008-09-30

    The RPE65 gene encodes the isomerase of the retinoid cycle, the enzymatic pathway that underlies mammalian vision. Mutations in RPE65 disrupt the retinoid cycle and cause a congenital human blindness known as Leber congenital amaurosis (LCA). We used adeno-associated virus-2-based RPE65 gene replacement therapy to treat three young adults with RPE65-LCA and measured their vision before and up to 90 days after the intervention. All three patients showed a statistically significant increase in visual sensitivity at 30 days after treatment localized to retinal areas that had received the vector. There were no changes in the effect between 30 and 90 days. Both cone- and rod-photoreceptor-based vision could be demonstrated in treated areas. For cones, there were increases of up to 1.7 log units (i.e., 50 fold); and for rods, there were gains of up to 4.8 log units (i.e., 63,000 fold). To assess what fraction of full vision potential was restored by gene therapy, we related the degree of light sensitivity to the level of remaining photoreceptors within the treatment area. We found that the intervention could overcome nearly all of the loss of light sensitivity resulting from the biochemical blockade. However, this reconstituted retinoid cycle was not completely normal. Resensitization kinetics of the newly treated rods were remarkably slow and required 8 h or more for the attainment of full sensitivity, compared with gene therapy.

  19. Image Segmentation for Food Quality Evaluation Using Computer Vision System

    Directory of Open Access Journals (Sweden)

    Nandhini. P

    2014-02-01

    Full Text Available Quality evaluation is an important factor in food processing industries using the computer vision system where human inspection systems provide high variability. In many countries food processing industries aims at producing defect free food materials to the consumers. Human evaluation techniques suffer from high labour costs, inconsistency and variability. Thus this paper provides various steps for identifying defects in the food material using the computer vision systems. Various steps in computer vision system are image acquisition, Preprocessing, image segmentation, feature identification and classification. The proposed framework provides the comparison of various filters where the hybrid median filter was selected as the filter with the high PSNR value and is used in preprocessing. Image segmentation techniques such as Colour based binary Image segmentation, Particle swarm optimization are compared and image segmentation parameters such as accuracy, sensitivity , specificity are calculated and found that colour based binary image segmentation is well suited for food quality evaluation. Finally this paper provides an efficient method for identifying the defected parts in food materials.

  20. Robert Grosseteste's colours

    CERN Document Server

    Sparavigna, Amelia Carolina

    2013-01-01

    Here I am proposing a translation and discussion of the De Colore, one of the short scientific treatises written by Robert Grosseteste. In this very short treatise of the mid-1220s, Grosseteste continued the discussion on light and colours he started in the De Iride. He describes two manners of counting colours: one gives an infinity of tones, the other counts seven colours. In both cases, colours are created by the purity or impurity of the transparent medium when light is passing through it. This medieval framework survived until Newton's experiments with prisms.

  1. Colour and Organization Studies

    DEFF Research Database (Denmark)

    Beyes, Timon

    2016-01-01

    Colour is inescapable. It fills and forms the world, shaping what can be felt and known, desired and expressed. It thus becomes social technology and organizational tool. At the same time, however, colour betrays, undermines and subverts the attempts to manage it. Based on an understanding...... of colour as aesthetic force and medium of transformation, the essay presents a montage of scenes that set up encounters with what colour does: how it affects organization, and how it is affected by organization; how it organizes what is given to perception, knowledge and organization itself, and how...

  2. Colourful FKS subtraction

    CERN Document Server

    Frixione, Stefano

    2011-01-01

    I formulate in a colour-friendly way the FKS method for the computation of QCD cross sections at the next-to-leading order accuracy. This is achieved through the definition of subtraction terms for squared matrix elements, constructed with single colour-dressed or pairs of colour-ordered amplitudes. The latter approach relies on the use of colour flows, is exact to all orders in $N$, and is thus particularly suited to being organized as a systematic expansion in 1/N.

  3. Internet Adaptation for Colour-Blind Persons

    Directory of Open Access Journals (Sweden)

    Rytė Žiūrienė

    2011-04-01

    Full Text Available Of all human race about 8% of males and 0,5% of females are colour-blind. It is estimated that in 2011 or 2012 there will be around 2 billion Internet users worldwide, so the number of colour-blind Internet users can reach about 200 million. Authors of this publication analyse issues that arise for colour-blind persons on the Internet and deliver the ways to make the Internet more comfortable. The special software is proposed as one of the ways together with comparison of its advantages.

  4. Graph Colouring Algorithms

    DEFF Research Database (Denmark)

    Husfeldt, Thore

    2015-01-01

    This chapter presents an introduction to graph colouring algorithms. The focus is on vertex-colouring algorithms that work for general classes of graphs with worst-case performance guarantees in a sequential model of computation. The presentation aims to demonstrate the breadth of available...

  5. Graph colouring algorithms

    OpenAIRE

    Husfeldt, Thore

    2015-01-01

    This chapter presents an introduction to graph colouring algorithms. The focus is on vertex-colouring algorithms that work for general classes of graphs with worst-case performance guarantees in a sequential model of computation. The presentation aims to demonstrate the breadth of available techniques and is organized by algorithmic paradigm.

  6. Colour and Organization Studies

    DEFF Research Database (Denmark)

    Beyes, Timon

    2016-01-01

    of colour as aesthetic force and medium of transformation, the essay presents a montage of scenes that set up encounters with what colour does: how it affects organization, and how it is affected by organization; how it organizes what is given to perception, knowledge and organization itself, and how...

  7. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue ...

  8. The colours of CERN

    CERN Document Server

    Laëtitia Pedroso

    2010-01-01

    Would you move into an office painted in a colour you hate? As we all know, taste in colour is individual. Thanks to the establishment of a new Painting Charter, conflicting opinions will be unified.   The four new paint colours established in the Painting Charter. There were many reasons behind the creation of the Painting Charter by the GS SEM Department. Unlike many companies, CERN has not until now regulated which colours can be used inside buildings. With many nationalities passing through CERN, tastes tend to differ: northern countries usually prefer colder colours, while southern countries seem to prefer warm colours. It’s not hard to imagine how quickly we could make a rainbow! In addition, whenever an office needs to be repainted, it can be difficult to find exactly the same colour. This results in entire walls being repainted, which increases the cost. If – by chance – the original colour is found, it could be out of stock. While ...

  9. Colour appearance descriptors for image browsing and retrieval

    Science.gov (United States)

    Othman, Aniza; Martinez, Kirk

    2008-01-01

    In this paper, we focus on the development of whole-scene colour appearance descriptors for classification to be used in browsing applications. The descriptors can classify a whole-scene image into various categories of semantically-based colour appearance. Colour appearance is an important feature and has been extensively used in image-analysis, retrieval and classification. By using pre-existing global CIELAB colour histograms, firstly, we try to develop metrics for whole-scene colour appearance: "colour strength", "high/low lightness" and "multicoloured". Secondly we propose methods using these metrics either alone or combined to classify whole-scene images into five categories of appearance: strong, pastel, dark, pale and multicoloured. Experiments show positive results and that the global colour histogram is actually useful and can be used for whole-scene colour appearance classification. We have also conducted a small-scale human evaluation test on whole-scene colour appearance. The results show, with suitable threshold settings, the proposed methods can describe the whole-scene colour appearance of images close to human classification. The descriptors were tested on thousands of images from various scenes: paintings, natural scenes, objects, photographs and documents. The colour appearance classifications are being integrated into an image browsing system which allows them to also be used to refine browsing.

  10. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been......Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new...

  11. Diversity in human hair growth, diameter, colour and shape. An in vivo study on young adults from 24 different ethnic groups observed in the five continents.

    Science.gov (United States)

    Loussouarn, Geneviève; Lozano, Isabelle; Panhard, Ségolène; Collaudin, Catherine; El Rawadi, Charles; Genain, Gilles

    2016-04-01

    Based on previous findings, from a worldwide study, classified the shapes of human hair into 8 major types, from straight to highly curly. This clearly extended the usual classification of hair into African, Asian or Caucasian types. However, determinations of hair growth parameters and hair density were excluded from such studies. To measure and compare the hair growth profiles of young adults without alopecia living in the five continents. 2249 young adults (18-35 years, females and males) without alopecia, originating from 24 various human ethnic groups were included in the study. Total hair density, telogen percentage and growth rate on three different scalp areas were measured, using non-invasive validated techniques. Natural hair colour level, curliness and hair diameter were additionally recorded, when practically possible. Diversity in hair growth parameters among the entire cohort was a key finding, with differences linked to scalp area, gender and geographic origin. Statistical approaches depicted African hair as having lower density and a slower growth rate. Asian hair showed a thicker diameter, with faster growth. Caucasian hair showed a high total hair density. On the one hand, this inter-continental study of hair growth parameters provides initial valuable base-line data on hair in young adults without alopecia, and on the other hand, further extends our knowledge of this unique human appendage, with some mosaic features, observed worldwide.

  12. A computer vision system for rapid search inspired by surface-based attention mechanisms from human perception.

    Science.gov (United States)

    Mohr, Johannes; Park, Jong-Han; Obermayer, Klaus

    2014-12-01

    Humans are highly efficient at visual search tasks by focusing selective attention on a small but relevant region of a visual scene. Recent results from biological vision suggest that surfaces of distinct physical objects form the basic units of this attentional process. The aim of this paper is to demonstrate how such surface-based attention mechanisms can speed up a computer vision system for visual search. The system uses fast perceptual grouping of depth cues to represent the visual world at the level of surfaces. This representation is stored in short-term memory and updated over time. A top-down guided attention mechanism sequentially selects one of the surfaces for detailed inspection by a recognition module. We show that the proposed attention framework requires little computational overhead (about 11 ms), but enables the system to operate in real-time and leads to a substantial increase in search efficiency.

  13. Physicochemical and physiological basis of dichromatic colour

    Science.gov (United States)

    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.

  14. Computational colour science using MATLAB

    CERN Document Server

    Westland, Stephen; Cheung, Vien

    2012-01-01

    Computational Colour Science Using MATLAB 2nd Edition offers a practical, problem-based approach to colour physics. The book focuses on the key issues encountered in modern colour engineering, including efficient representation of colour information, Fourier analysis of reflectance spectra and advanced colorimetric computation. Emphasis is placed on the practical applications rather than the techniques themselves, with material structured around key topics. These topics include colour calibration of visual displays, computer recipe prediction and models for colour-appearance prediction. Each t

  15. Vision Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Vision Lab personnel perform research, development, testing and evaluation of eye protection and vision performance. The lab maintains and continues to develop...

  16. Vision Screening

    Science.gov (United States)

    ... of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations Loading... Most Common Searches Adult Strabismus Amblyopia Cataract Conjunctivitis Corneal Abrasions Dilating Eye ...

  17. Effects of Memory Colour on Colour Constancy for Unknown Coloured Objects

    Directory of Open Access Journals (Sweden)

    Jeroen J M Granzier

    2012-04-01

    Full Text Available The perception of an object's colour remains constant despite large variations in the chromaticity of the illumination—colour constancy. Hering suggested that memory colours, the typical colours of objects, could help in estimating the illuminant's colour and therefore be an important factor in establishing colour constancy. Here we test whether the presence of objects with diagnostical colours (fruits, vegetables, etc within a scene influence colour constancy for unknown coloured objects in the scene. Subjects matched one of four Munsell papers placed in a scene illuminated under either a reddish or a greenish lamp with the Munsell book of colour illuminated by a neutral lamp. The Munsell papers were embedded in four different scenes—one scene containing diagnostically coloured objects, one scene containing incongruent coloured objects, a third scene with geometrical objects of the same colour as the diagnostically coloured objects, and one scene containing non-diagnostically coloured objects (eg, a yellow coffee mug. All objects were placed against a black background. Colour constancy was on average significantly higher for the scene containing the diagnostically coloured objects compared with the other scenes tested. We conclude that the colours of familiar objects help in obtaining colour constancy for unknown objects.

  18. The effect of test chart design and human factors on visual performance with night vision goggles.

    Science.gov (United States)

    Silberman, W S; Apsey, D; Ivan, D J; Jackson, W G; Mitchell, G W

    1994-12-01

    In an effort to increase flight safety, it is imperative to learn as much as possible about the man-goggle interrelationship. This study was undertaken to see if type of goggle or other covariates might affect visual acuity (VA). We tested the VA of 103 aircrew with both the AN/PVS-5 and Aviator's Night Vision Imaging System (ANVIS) goggles using a Snellen vision testing chart and the new Night Vision Goggle (NVG) Resolution (Grid Type) Chart. Average VA's using ANVIS (Snellen = 20/38, Grid = 20/45) were significantly better (p goggles and for non-smokers using AN/PVS-5 goggles. Visual acuity is better with ANVIS than with AN/PVS-5 goggles, and may be affected somewhat by wearing spectacles, and by smoking.

  19. A simplified method for generation of pseudo natural colours from colour infrared aerial photos

    DEFF Research Database (Denmark)

    Knudsen, Thomas; Olsen, Brian Pilemann

    . In the second step the blue colour component is estimated using tailored models for each domain. Green and red colour components are taken directly fron the CIR photo. The visual impression of the results from the 2 step method is only slightly inferior to the original 7 step method. The implementation, however......In spite of their high potential for automated discrimination between vegetation and human made objects, colour-infrared (CIR) aerial photos have not been in widespread use for traditional photogrammetric mapping. This is probably due to their awkward colour representation invalidating the visual...... analytical experience of the stereo analysts doing the actual registration of the topographical data. In this paper, we present a method for generating pseudo natural colour (PNC) representations from CIR photos. This enables the combination of automated vegetation discrimination with traditional manual...

  20. Cross-modal associations in synaesthesia: Vowel colours in the ear of the beholder

    OpenAIRE

    Moos, Anja; Smith, Rachel; Miller, Sam R; Simmons, David R

    2014-01-01

    Human speech conveys many forms of information, but for some exceptional individuals (synaesthetes), listening to speech sounds can automatically induce visual percepts such as colours. In this experiment, grapheme–colour synaesthetes and controls were asked to assign colours, or shades of grey, to different vowel sounds. We then investigated whether the acoustic content of these vowel sounds influenced participants' colour and grey-shade choices. We found that both colour and grey-shade asso...

  1. Statistical Hypothesis Testing using CNN Features for Synthesis of Adversarial Counterexamples to Human and Object Detection Vision Systems

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Sunny [Univ. of Central Florida, Orlando, FL (United States); Jha, Sumit Kumar [Univ. of Central Florida, Orlando, FL (United States); Pullum, Laura L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ramanathan, Arvind [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-01

    Validating the correctness of human detection vision systems is crucial for safety applications such as pedestrian collision avoidance in autonomous vehicles. The enormous space of possible inputs to such an intelligent system makes it difficult to design test cases for such systems. In this report, we present our tool MAYA that uses an error model derived from a convolutional neural network (CNN) to explore the space of images similar to a given input image, and then tests the correctness of a given human or object detection system on such perturbed images. We demonstrate the capability of our tool on the pre-trained Histogram-of-Oriented-Gradients (HOG) human detection algorithm implemented in the popular OpenCV toolset and the Caffe object detection system pre-trained on the ImageNet benchmark. Our tool may serve as a testing resource for the designers of intelligent human and object detection systems.

  2. LED-Based Colour Sensing System

    Directory of Open Access Journals (Sweden)

    Ibrahim AL-BAHADLY

    2010-03-01

    Full Text Available This paper presents a new colour sensing system for measuring the colour of car paint accurately enough to reproduce the paint proportions to cover up scratches or wear on a car. The aim is to repaint a car’s damaged area at a fraction of the cost of repainting the whole car. The proposed colour sensing system is based on Light Emitting Diode (LED. A prototype for the system has been designed, built, and tested. During this work light was researched as well as lighting sources, how light travels, how light reflects and refracts, ways light can be quantized, the human eye, why cameras look accurate, lighting conditions and their effects, and the emergence of colour.

  3. Teaching for Humanity in a Neoliberal World: Visions of Education in Serbia

    Science.gov (United States)

    Dull, Laura J.

    2012-01-01

    In Serbia, teachers and policy makers express different and sometimes competing visions of education. Teachers express their desire to "awaken" students by using progressive pedagogies, while European Union and World Bank reformers appropriate progressive education in the service of neoliberal goals. The research findings presented here…

  4. Teaching for Humanity in a Neoliberal World: Visions of Education in Serbia

    Science.gov (United States)

    Dull, Laura J.

    2012-01-01

    In Serbia, teachers and policy makers express different and sometimes competing visions of education. Teachers express their desire to "awaken" students by using progressive pedagogies, while European Union and World Bank reformers appropriate progressive education in the service of neoliberal goals. The research findings presented here…

  5. Plasmonic colour laser printing

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil

    2016-01-01

    -beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation...... that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours...

  6. Game Coloured Petri Nets

    DEFF Research Database (Denmark)

    Westergaard, Michael

    2006-01-01

    This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachability...... analysis of this net class, and an application of game coloured Petri nets to automatically generate easy-to-understand visualizations of the model by exploiting the knowledge that some parts of the model are not interesting from a visualization perspective (i.e. they are part of the environment...

  7. Colour From the Perspective of Hadith: an Overview

    Directory of Open Access Journals (Sweden)

    Zainan Nazri Mohd Khairul Nizam

    2015-01-01

    Full Text Available Colour is mentioned a few times in the Prophetic Traditions, signifying its values and symbolic representation for the people. The Prophet PBUH highlighted the significance of certain colours by describing his preferred colours for his clothing and he also approved or discouraged the usage of certain colours. Among the colours that are specifically mentioned and found in the hadith are white, red, green, black and yellow. These colours give different connotations as they were used in the Prophet’s attires during battles and other occasions; and some bring about specific understanding, as stated by the Prophet PBUH. Interestingly, the use of certain colours as found in the hadith corresponds to that mentioned in the Qur’an. Thus, this paper will observe the discussion among Muhaddithin regarding to the topic of colours in terms of its definition, function, significance and impact on the human life. The variety of meaning and understanding of colours according to different perspectives and cultures will also be discussed. The implications of using specific colours psychologically and scientifically will also be exposed in order to discover the connection between colours in the Prophetic Traditions and in our contemporary life.

  8. Distance-constrained grid colouring

    Directory of Open Access Journals (Sweden)

    Aszalós László

    2016-06-01

    Full Text Available Distance-constrained colouring is a mathematical model of the frequency assignment problem. This colouring can be treated as an optimization problem so we can use the toolbar of the optimization to solve concrete problems. In this paper, we show performance of distance-constrained grid colouring for two methods which are good in map colouring.

  9. Eat by Colour

    Institute of Scientific and Technical Information of China (English)

    David Heber; 谢琼

    2004-01-01

    <正> COLOUR is the key to good nutrition. Yet what colour is an increasing number of people’s diet? Beige.As a physician who has studied nutrition and cancer prevention for more than 20 years, I believe that bland diets actually account for the most common diseases, including heart disease, cancer and what I call diabesity-a booming epidemic of obesity and diabetes.

  10. Game Coloured Petri Nets

    DEFF Research Database (Denmark)

    Westergaard, Michael

    2006-01-01

    This paper introduces the notion of game coloured Petri nets. This allows the modeler to explicitly model what parts of the model comprise the modeled system and what parts are the environment of the modeled system. We give the formal definition of game coloured Petri nets, a means of reachabilit......, and not controllable by the system itself, or they are part of the system itself and therefore we need not worry about them)....

  11. Machine Vision-Based Measurement Systems for Fruit and Vegetable Quality Control in Postharvest.

    Science.gov (United States)

    Blasco, José; Munera, Sandra; Aleixos, Nuria; Cubero, Sergio; Molto, Enrique

    2017-03-14

    Individual items of any agricultural commodity are different from each other in terms of colour, shape or size. Furthermore, as they are living thing, they change their quality attributes over time, thereby making the development of accurate automatic inspection machines a challenging task. Machine vision-based systems and new optical technologies make it feasible to create non-destructive control and monitoring tools for quality assessment to ensure adequate accomplishment of food standards. Such systems are much faster than any manual non-destructive examination of fruit and vegetable quality, thus allowing the whole production to be inspected with objective and repeatable criteria. Moreover, current technology makes it possible to inspect the fruit in spectral ranges beyond the sensibility of the human eye, for instance in the ultraviolet and near-infrared regions. Machine vision-based applications require the use of multiple technologies and knowledge, ranging from those related to image acquisition (illumination, cameras, etc.) to the development of algorithms for spectral image analysis. Machine vision-based systems for inspecting fruit and vegetables are targeted towards different purposes, from in-line sorting into commercial categories to the detection of contaminants or the distribution of specific chemical compounds on the product's surface. This chapter summarises the current state of the art in these techniques, starting with systems based on colour images for the inspection of conventional colour, shape or external defects and then goes on to consider recent developments in spectral image analysis for internal quality assessment or contaminant detection.

  12. Low Cost Night Vision System for Intruder Detection

    Science.gov (United States)

    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.

  13. Multicolour interphase cytogenetics: 24 chromosome probes, 6 colours, 4 layers

    OpenAIRE

    2011-01-01

    From the late 1980s onwards, the use of DNA probes to visualise sequences on individual chromosomes (fluorescent in-situ hybridisation - FISH) revolutionised the study of cytogenetics. Following single colour experiments, more fluorochromes were added, culminating in a 24 colour assay that could distinguish all human chromosomes. Interphase cytogenetics (the detection of chromosome copy number in interphase nuclei) soon followed, however 24 colour experiments are hampered for this application...

  14. Use of HPLC/UPLC-spectrophotometry for detection of formazan in in vitro Reconstructed human Tissue (RhT)-based test methods employing the MTT-reduction assay to expand their applicability to strongly coloured test chemicals.

    Science.gov (United States)

    Alépée, N; Barroso, J; De Smedt, A; De Wever, B; Hibatallah, J; Klaric, M; Mewes, K R; Millet, M; Pfannenbecker, U; Tailhardat, M; Templier, M; McNamee, P

    2015-06-01

    A number of in vitro test methods using Reconstructed human Tissues (RhT) are regulatory accepted for evaluation of skin corrosion/irritation. In such methods, test chemical corrosion/irritation potential is determined by measuring tissue viability using the photometric MTT-reduction assay. A known limitation of this assay is possible interference of strongly coloured test chemicals with measurement of formazan by absorbance (OD). To address this, Cosmetics Europe evaluated use of HPLC/UPLC-spectrophotometry as an alternative formazan measurement system. Using the approach recommended by the FDA guidance for validation of bio-analytical methods, three independent laboratories established and qualified their HPLC/UPLC-spectrophotometry systems to reproducibly measure formazan from tissue extracts. Up to 26 chemicals were then tested in RhT test systems for eye/skin irritation and skin corrosion. Results support that: (1) HPLC/UPLC-spectrophotometry formazan measurement is highly reproducible; (2) formazan measurement by HPLC/UPLC-spectrophotometry and OD gave almost identical tissue viabilities for test chemicals not exhibiting colour interference nor direct MTT reduction; (3) independent of the test system used, HPLC/UPLC-spectrophotometry can measure formazan for strongly coloured test chemicals when this is not possible by absorbance only. It is therefore recommended that HPLC/UPLC-spectrophotometry to measure formazan be included in the procedures of in vitro RhT-based test methods, irrespective of the test system used and the toxicity endpoint evaluated to extend the applicability of these test methods to strongly coloured chemicals.

  15. Biological basis for space-variant sensor design I: parameters of monkey and human spatial vision

    Science.gov (United States)

    Rojer, Alan S.; Schwartz, Eric L.

    1991-02-01

    Biological sensor design has long provided inspiration for sensor design in machine vision. However relatively little attention has been paid to the actual design parameters provided by biological systems as opposed to the general nature of biological vision architectures. In the present paper we will provide a review of current knowledge of primate spatial vision design parameters and will present recent experimental and modeling work from our lab which demonstrates that a numerical conformal mapping which is a refinement of our previous complex logarithmic model provides the best current summary of this feature of the primate visual system. In this paper we will review recent work from our laboratory which has characterized some of the spatial architectures of the primate visual system. In particular we will review experimental and modeling studies which indicate that: . The global spatial architecture of primate visual cortex is well summarized by a numerical conformal mapping whose simplest analytic approximation is the complex logarithm function . The columnar sub-structure of primate visual cortex can be well summarized by a model based on a band-pass filtered white noise. We will also refer to ongoing work in our lab which demonstrates that: . The joint columnar/map structure of primate visual cortex can be modeled and summarized in terms of a new algorithm the ''''proto-column'''' algorithm. This work provides a reference-point for current engineering approaches to novel architectures for

  16. Quantization Selection of Colour Histogram Bins to Categorize the Colour Appearance of Landscape Paintings for Image Retrieval

    Directory of Open Access Journals (Sweden)

    Aniza Othman

    2016-12-01

    Full Text Available In the world of today, most images are digitized and kept in digital libraries for better organization and management. With the growth of information and communication technology, collection holders such as museums or cultural institutions have been increasingly interested in making their collections available anytime and anywhere for any Image Retrieval (IR activities such as browsing and searching. In a colour image retrieval application, images retrieved by users are accomplished according to their specifications on what they want or acquire, which could be based upon so many concepts. We suggest an  approach to categorize the colour appearances of whole scene landscape painting images based on human colour perception. The colour features in the image are represented using a colour histogram. We then find  the suitable quantization bins that can be used to generate optimum colour histograms for all categories of colour appearances, which is selected based on theHarmonic Mean of the precision and recall,  also known as F-Score percentage higher saturated value. Colour appearance attributes in the CIELab colour model (L-Lightness, a and b are colour-opponent dimension are used to generate colour appearance feature vectors namely the saturation metric, lightness metric and multicoloured metric. For the categorizations, we use the Nearest Neighbour (NN method to detect the classes by using the predefined colour appearance descriptor measures and the pre-set thresholds.  The experimental results show that the quantization of CIELab colour model into 11 uniformly bins for each component had achieved the optimum result for all colour appearances categories.

  17. Use of HPLC/UPLC-spectrophotometry for detection of formazan in in vitro Reconstructed human Tissue (RhT)-based test methods employing the MTT-reduction assay to expand their applicability to strongly coloured test chemicals

    OpenAIRE

    ALEPEE Nathalie; VIEGAS BARROSO JOAO FILIPE; De Smedt, Ann; Wever, Bart De; Hibatallah, Jalila; Klaric, Martina; MEWES Karsten R.; Millet, Marion; Pfannenbecker, Uwe; Tailhardat, Magalie; TEMPLIER Marie; McNamee, Pauline

    2015-01-01

    A number of in vitro test methods using Reconstructed human Tissues (RhT) are regulatory accepted for evaluation of skin corrosion/irritation. In such methods, test chemical corrosion/irritation potential is determined by measuring tissue viability using the photometric MTT-reduction assay. A known limitation of this assay is possible interference of strongly coloured test chemicals with measurement of formazan by absorbance (OD). To address this, Cosmetics Europe evaluated use of HPLC/UPLCsp...

  18. Gene therapy for red-green colour blindness in adult primates.

    Science.gov (United States)

    Mancuso, Katherine; Hauswirth, William W; Li, Qiuhong; Connor, Thomas B; Kuchenbecker, James A; Mauck, Matthew C; Neitz, Jay; Neitz, Maureen

    2009-10-08

    Red-green colour blindness, which results from the absence of either the long- (L) or the middle- (M) wavelength-sensitive visual photopigments, is the most common single locus genetic disorder. Here we explore the possibility of curing colour blindness using gene therapy in experiments on adult monkeys that had been colour blind since birth. A third type of cone pigment was added to dichromatic retinas, providing the receptoral basis for trichromatic colour vision. This opened a new avenue to explore the requirements for establishing the neural circuits for a new dimension of colour sensation. Classic visual deprivation experiments have led to the expectation that neural connections established during development would not appropriately process an input that was not present from birth. Therefore, it was believed that the treatment of congenital vision disorders would be ineffective unless administered to the very young. However, here we show that the addition of a third opsin in adult red-green colour-deficient primates was sufficient to produce trichromatic colour vision behaviour. Thus, trichromacy can arise from a single addition of a third cone class and it does not require an early developmental process. This provides a positive outlook for the potential of gene therapy to cure adult vision disorders.

  19. Why background colour matters to bees and flowers.

    Science.gov (United States)

    Bukovac, Zoë; Shrestha, Mani; Garcia, Jair E; Burd, Martin; Dorin, Alan; Dyer, Adrian G

    2017-05-01

    Flowers are often viewed by bee pollinators against a variety of different backgrounds. On the Australian continent, backgrounds are very diverse and include surface examples of all major geological stages of the Earth's history, which have been present during the entire evolutionary period of Angiosperms. Flower signals in Australia are also representative of typical worldwide evolutionary spectral adaptations that enable successful pollination. We measured the spectral properties of 581 natural surfaces, including rocks, sand, green leaves, and dry plant materials, sampled from tropical Cairns through to the southern tip of mainland Australia. We modelled in a hexagon colour space, how interactions between background spectra and flower-like colour stimuli affect reliable discrimination and detection in bee pollinators. We calculated the extent to which a given locus would be conflated with the loci of a different flower-colour stimulus using empirically determined colour discrimination regions for bee vision. Our results reveal that whilst colour signals are robust in homogeneous background viewing conditions, there could be significant pressure on plant flowers to evolve saliently-different colours to overcome background spectral noise. We thus show that perceptual noise has a large influence on how colour information can be used in natural conditions.

  20. Temporal analysis of the chromatic flash VEP--separate colour and luminance contrast components.

    Science.gov (United States)

    Klistorner, A; Crewther, D P; Crewther, S G

    1998-12-01

    Temporal analysis of the chromatic flash visual evoked potential (VEP) was studied in human subjects with normal and anomalous colour vision using a deterministic pseudo-random binary stimulus (VERIS). Five experiments were carried out on four normal subjects investigating heterochromatic red-green exchange and single colour/achromatic (either red/grey or green/grey) exchange over a wide range of luminance ratios for the two stimuli, the effects of lowered mean luminance on the chromatic VEP and the effects of colour desaturation at constant mean luminance and constant luminance contrast. Finally, the performance of three dichromats, a protanope and two deuteranopes, on heterochromatic exchange VEP and on colour desaturation were investigated. In contrast to the chromatic electroretinogram, which shows great symmetry with respect to luminance ratio on opposite sides of the isoluminant point, the chromatic VEP demonstrated a distinct asymmetry when the colours exchanged included red. On the red side of isoluminance (red more luminant than green), a wave with longer latency and altered waveform became dominant. The effects of green stimulation were indistinguishable from those of achromatic stimulation at the same luminance contrast over the whole range of chromatic contrast and for all levels of desaturation studied. Desaturation of red with constant luminance contrast (desaturated red/grey stimulation) resulted in a systematic alteration in the evoked waveform. Subtraction of the achromatic first- and second-order responses from responses recorded in the red desaturation series resulted in remarkably uniform waveforms, with peak amplitudes growing linearly with saturation. The absence of interaction between achromatic and coloured components for all (including the most intense colour) stimulus parameters used suggests that the generators of these components are separate. Recordings from the dichromats showed that the contrast response minimum shifted from the point

  1. Computational vision

    CERN Document Server

    Wechsler, Harry

    1990-01-01

    The book is suitable for advanced courses in computer vision and image processing. In addition to providing an overall view of computational vision, it contains extensive material on topics that are not usually covered in computer vision texts (including parallel distributed processing and neural networks) and considers many real applications.

  2. Accurate Colour Reproduction in Prepress

    Directory of Open Access Journals (Sweden)

    Ákos Borbély

    2008-06-01

    Full Text Available The adjustment of colour to achieve an acceptable match between the displayed(soft copy and printed (hard copy document is an important task in prepress. In order toachieve such match colour management systems are used, these systems implementstandards established by the International Colour Consortium (ICC.A key step of the colour management process is the calibration of display and outputdevices, the definition of the relationship between the native colour space of the device anda standard device-independent colour space. In this work the usability of the ICC colourmanagement standard was investigated in case of flat panel LCD display calibration.

  3. MAJOR AND LYMPHOCYTE POPULATIONS OF HUMAN PERIPHERAL BLOOD LYMPHOCYTES AND THEIR REFERENCE VALUES, AS ASSAYED BY MULTI-COLOUR CYTOMETRY

    Directory of Open Access Journals (Sweden)

    S. V. Khaidukov

    2009-01-01

    Full Text Available Abstract. Determination of lymphocyte subpopulations and their phenotypes is an important diagnostic feature, in order to elucidate some disturbances connected with immune system functioning. However, insufficient data are obtained when analyzing only major populations of peripheral lymphocytes. In order to perform clinical diagnostics, the data about minor lymphocytic populations and activated cellular pools seem to be more pertinent.Studies of peripheral blood cell subpopulations of healthy donors performed in different Russian regions allowed to assess quantitative distribution intervals for both major and minor immune cell subpopulations in humans. The results obtained, as compared with data from literature, provide an evidence for similar reference intervals for main immune cell subpopulations in healthy donors, independent on their habitation area.Present work has resulted into development of algorithms for cytometric studies and generation of certain panels of monoclonal antibodies enabling evaluation of all main lymphocyte subpopulations, as well as their minor subsets participating in emerging immune response. The distribution intervals have been estimated for such minor subpopulations, as B1- and B2-lymphocytes, memory B-cells, γδ- and αβT-cells, regulatory and naїve T-cells, cytotoxic and secretory NK-cell polupations.The results of present study, while been performed with peripheral blood of healthy donors, may provide a basis of reference values when studying subpopulation profile of immune cells.

  4. Human Vision Inspired Based Image Illumination Enhancement by Using Local Singular Value Decomposition and Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Gholamreza Anbarjafari

    2015-01-01

    Full Text Available Recently, many computer vision applications are being inspired by human behavior, or human visual system. Also it is known that illumination issues have always been an important problem in many image processing applications. In this work we propose a new image illumination enhancement technique which is inspired from the human visual system behavior on illumination correction. The proposed technique uses local singular value decomposition (SVD and discrete wavelet transforms (DWT, inspired from the fact that human visual system equalizes a scene by disregarding the extreme illuminated areas. In other words, human brain uses local illumination enhancement and this localization is based on the extreme illuminations, e.g. existence or absence of too much light. In this technique, after dividing the image into several locals, each local is converted into the DWT domain and after updating the singular value matrix of the respective low-low subband, the local is reconstructed by using inverse DWT (IDWT. Combination of locals results in the equalized image. The technique is compared with the standard general histogram equalization (GHE and local histogram equalization (LHE. The experimental results are showing the superiority of the proposed method over the aforementioned techniques.

  5. Imporved method for stereo vision-based human detection for a mobile robot following a target person

    Directory of Open Access Journals (Sweden)

    Ali, Badar

    2015-05-01

    Full Text Available Interaction between humans and robots is a fundamental need for assistive and service robots. Their ability to detect and track people is a basic requirement for interaction with human beings. This article presents a new approach to human detection and targeted person tracking by a mobile robot. Our work is based on earlier methods that used stereo vision-based tracking linked directly with Hu moment-based detection. The earlier technique was based on the assumption that only one person is present in the environment – the target person – and it was not able to handle more than this one person. In our novel method, we solved this problem by using the Haar-based human detection method, and included a target person selection step before initialising tracking. Furthermore, rather than linking the Kalman filter directly with human detection, we implemented the tracking method before the Kalman filter-based estimation. We used the Pioneer 3AT robot, equipped with stereo camera and sonars, as the test platform.

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

    Science.gov (United States)

    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.

  7. A human performance/workload evaluation of the AN/PVS-5 bifocal night vision goggles.

    Science.gov (United States)

    Stone, L W; Sanders, M G; Glick, D D; Wiley, R W; Kimball, K A

    1980-08-01

    Eight experienced U.S. Army aviators performed various maneuvers in an instrumented helicopter to test the relative usability of two bifocal-configured night vision goggles. Both configurations were statistically better than the unmodified arrangement when looking at a pilot's ability to fly a standard traffic pattern and to hold a precise altitude at night. The subjective data, supported by comparative flight performances with the two bifocals, further suggested that a 24% bifocal version was more desirable than a 14% configuration. The inference is that the reduced inside field of view presented by the 14% bifocal interferes with a pilot's ability to readily locate instruments once he has directed his attention inside the cockpit.

  8. Morphological patterns and their colour.

    Science.gov (United States)

    Dadam, James; Albertazzi, Liliana; Da Pos, Osvaldo; Canal, Luisa; Micciolo, Rocco

    2012-04-01

    This study analyzed qualitative aspects in perception, particularly the relationship between morphological aspects of biological shapes and colour. The experiment reported by the study assessed the functional relation between shape and colour and, in particular, the relations among the patterns of shapes appearing in perceptual configurations, as well as certain characteristics of colour. Participants were shown 32 natural images and were asked to match them with a colour. The results indicated that some figures were more frequently associated (positively or negatively) with some colours instead of others. Type of shape, texture, and three-dimensionality were important elements in the participants' choices. Rounded figures and non-holed figures had positive matches with red; elongated figures were associated with colours between blue and green; and holed figures showed positive matches with colours between green and yellow. Type of shape and texture also exhibited a relationship with the warmth of the colour.

  9. ATLAS Colouring Book

    CERN Multimedia

    Anthony, Katarina

    2016-01-01

    The ATLAS Experiment Colouring Book is a free-to-download educational book, ideal for kids aged 5-9. It aims to introduce children to the field of High-Energy Physics, as well as the work being carried out by the ATLAS Collaboration.

  10. Coloured Petri Nets

    CERN Document Server

    Jensen, Kurt

    2009-01-01

    Coloured Petri Nets (CPN) is a graphical language for modelling and validating concurrent and distributed systems, and other systems in which concurrency plays a major role. This book introduces the constructs of the CPN modelling language and presents the related analysis methods. It provides a comprehensive road map for the practical use of CPN.

  11. Colour Reconnection at LEPII

    CERN Document Server

    Abreu, P

    2001-01-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, Aleph, Delphi, L3 and Opal, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method, are yet inconclusive.

  12. Plasmonic colour laser printing

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil

    2016-01-01

    -beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation...

  13. Colour changes by laser irradiation of reddish building limestones

    Energy Technology Data Exchange (ETDEWEB)

    Grossi, C.M., E-mail: c.grossi-sampedro@uea.ac.uk [School of Health Sciences, University of East Anglia, Norwich NR4 7TJ (United Kingdom); Benavente, D. [Department of Earth and Environment Sciences, University of Alicante. 03690 Alicante (Spain)

    2016-10-30

    Highlights: • This is the first time that XPS is used to determine the cause of colour change in coloured stones when cleaned with laser at 1064 nm. • We demonstrate that the colour change in red limestones is due to a reduction in the state of oxidation of iron, in this case present as hematite. • XPS could be routinely used to analyse causes of colour changes during laser cleaning in other types of coloured building stones. - Abstract: We have used X-ray photoelectron spectroscopy (XPS) as a novel method to investigate the causes of colour changes in a reddish limestone under irradiation by a Q-switched Nd:YAG 1064 nm laser. We irradiated clean dry and wet surfaces of Pidramuelle Roja, a building stone frequently used in the Asturian heritage, at fluences ranging from 0.12 to 1.47 J cm{sup −2}. We measured the colour coordinates and undertook XPS analysis of the state of oxidation of iron both before and after irradiation. Visible colour changes and potential aesthetic damage occurred on dry surfaces from a fluence of 0.31 J cm{sup −2}, with the stone showing a greening effect and very intense darkening. The colour change on dry surfaces was considerably higher than on wet surfaces, which at the highest fluence (1.47 J cm{sup −2}) was also above the human visual detection threshold. The use of XPS demonstrated that the change in colour (chroma and hue) is associated with a reduction in the iron oxidation state on dry surfaces during laser irradiation. This points out to a potential routinary use of XPS to analyse causes of colour changes during laser cleaning in other types of coloured building stones.

  14. Vision Based Obstacle Detection mechanism of a Fixed Wing UAV

    Directory of Open Access Journals (Sweden)

    S.N. Omkar

    2014-03-01

    Full Text Available In this paper we have developed a vision based navigation and obstacle detection mechanism for unmanned aerial vehicles (UAVs which can be used effectively in GPS denied regions as well as in regions where remote controlled UAV navigation is impossible thus making the UAV more versatile and fully autonomous. We used a fixed single onboard video camera on the UAV that extracts images of the environment of a UAV. These images are then processed and detect an obstacle in the path if any. This method is effective in detecting dark as well as light coloured obstacles in the vicinity of the UAV. We developed two algorithms. The first one is to detect the horizon and land in the images extracted from the camera and to detect an obstacle in its path. The second one is specifically to detect a light coloured obstacle in the environment thus making our method more precise. The time taken for processing of the images and generating a result is very small thus this algorithm is also fit to be used in real time applications. These Algorithms are more effective than previously developed in this field because this algorithm does the detection of any obstacle without knowing the size of it beforehand. This algorithm is also capable of detecting light coloured obstacles in the sky which otherwise might be missed by an UAV or even a human pilot sometimes. Thus it makes the navigation more precise.

  15. Colour displays for categorical images

    NARCIS (Netherlands)

    Glasbey, C.; Heijden, van der G.W.A.M.; Toh, V.F.K.; Gray, A.J.

    2007-01-01

    We propose a method for identifying a set of colours for displaying 2D and 3D categorical images when the categories are unordered labels. The principle is to find maximally distinct sets of colours. We either generate colours sequentially, to maximize the dissimilarity or distance between a new col

  16. Towards Video Quality Metrics Based on Colour Fractal Geometry

    Directory of Open Access Journals (Sweden)

    Richard Noël

    2010-01-01

    Full Text Available Vision is a complex process that integrates multiple aspects of an image: spatial frequencies, topology and colour. Unfortunately, so far, all these elements were independently took into consideration for the development of image and video quality metrics, therefore we propose an approach that blends together all of them. Our approach allows for the analysis of the complexity of colour images in the RGB colour space, based on the probabilistic algorithm for calculating the fractal dimension and lacunarity. Given that all the existing fractal approaches are defined only for gray-scale images, we extend them to the colour domain. We show how these two colour fractal features capture the multiple aspects that characterize the degradation of the video signal, based on the hypothesis that the quality degradation perceived by the user is directly proportional to the modification of the fractal complexity. We claim that the two colour fractal measures can objectively assess the quality of the video signal and they can be used as metrics for the user-perceived video quality degradation and we validated them through experimental results obtained for an MPEG-4 video streaming application; finally, the results are compared against the ones given by unanimously-accepted metrics and subjective tests.

  17. Living with vision loss

    Science.gov (United States)

    Diabetes - vision loss; Retinopathy - vision loss; Low vision; Blindness - vision loss ... Low vision is a visual disability. Wearing regular glasses or contacts does not help. People with low vision have ...

  18. Transmission of colour and acuity signals by parvocellular cells in marmoset monkeys.

    Science.gov (United States)

    Martin, Paul R; Blessing, Esther M; Buzás, Péter; Szmajda, Brett A; Forte, Jason D

    2011-06-01

    The red-green axis of colour vision evolved recently in primate evolutionary history. Signals serving red-green colour vision travel together with signals serving spatial vision, in the parvocellular (PC) division of the subcortical visual pathway. However, the question of whether receptive fields of PC pathway cells are specialized to transmit red-green colour signals remains unresolved. We addressed this question in single-cell recordings from the lateral geniculate nucleus of anaesthetized marmosets. Marmosets show a high proportion of dichromatic (red-green colour-blind) individuals, allowing spatial and colour tuning properties of PC cells to be directly compared in dichromatic and trichromatic visual systems. We measured spatial frequency tuning for sine gratings that provided selective stimulation of individual photoreceptor types. We found that in trichromatic marmosets, the foveal visual field representation is dominated by red-green colour-selective PC cells. Colour selectivity of PC cells is reduced at greater eccentricities, but cone inputs to centre and surround are biased to create more selectivity than predicted by a purely 'random wiring' model. Thus, one-to-one connections in the fovea are sufficient, but not necessary, to create colour-selective responses. The distribution of spatial tuning properties for achromatic stimuli shows almost complete overlap between PC cells recorded in dichromatic and trichromatic marmosets. These data indicate that transmission of red-green colour signals has been enabled by centre-surround receptive fields of PC cells, and has not altered the capacity of PC cells to serve high-acuity vision at high stimulus contrast.

  19. Psychophysics of human vision: The key to improved camouflage pattern design

    CSIR Research Space (South Africa)

    Baumbach, J

    2010-11-01

    Full Text Available determined by the factors mentioned above, but also by the (possible) observer/enemy. The human visual system (which includes the brain) is one of the most powerful observation systems. This paper examined the eye-brain interaction, and how... these properties could aid camouflage pattern development. 2. The Human Visual System The human visual system is very complex, therefore this study was undertaken in order to better understand the human eye-brain interaction. It also assisted in forming a...

  20. Hue-specific colour memory impairment in an individual with intact colour perception and colour naming.

    Science.gov (United States)

    Jakobson, L S; Pearson, P M; Robertson, B

    2008-01-15

    Cases of hue-selective dyschomatopsias, together with the results of recent optical imaging studies [Xiao, Y., Casti, A. R. R., Xiao, J., & Kaplan, E. (2006). A spatially organized representation of colour in macaque primary visual cortex. Perception, 35, ECVP Abstract Supplement; Xiao, Y., Wang, Y., & Felleman, D. J. (2003). A spatially organized representation of colour in macaque cortical area V2. Nature, 421, 535-539], have provided support for the idea that different colours are processed in spatially distinct regions of extrastriate cortex. In the present report, we provide evidence suggesting that a similar, but distinct, map may exist for representations of colour in memory. This evidence comes from observations of a young woman (QP) who demonstrates an isolated deficit in colour memory secondary to a concussive episode. Despite having normal colour perception and colour naming skills, and above-average memory skills in other domains, QP's ability to recall visually encoded colour information over short retention intervals is dramatically impaired. Her long-term memory for colour and her colour imagery skills are also abnormal. Surprisingly, however, these impairments are not seen with all hues; specifically, her ability to remember or imagine blue shades is spared. This interesting case contributes to the literature suggesting that colour perception, naming, and memory can be clinically dissociated, and provides insights into the organization of colour information in memory.

  1. Deep Networks Can Resemble Human Feed-forward Vision in Invariant Object Recognition

    Science.gov (United States)

    Kheradpisheh, Saeed Reza; Ghodrati, Masoud; Ganjtabesh, Mohammad; Masquelier, Timothée

    2016-09-01

    Deep convolutional neural networks (DCNNs) have attracted much attention recently, and have shown to be able to recognize thousands of object categories in natural image databases. Their architecture is somewhat similar to that of the human visual system: both use restricted receptive fields, and a hierarchy of layers which progressively extract more and more abstracted features. Yet it is unknown whether DCNNs match human performance at the task of view-invariant object recognition, whether they make similar errors and use similar representations for this task, and whether the answers depend on the magnitude of the viewpoint variations. To investigate these issues, we benchmarked eight state-of-the-art DCNNs, the HMAX model, and a baseline shallow model and compared their results to those of humans with backward masking. Unlike in all previous DCNN studies, we carefully controlled the magnitude of the viewpoint variations to demonstrate that shallow nets can outperform deep nets and humans when variations are weak. When facing larger variations, however, more layers were needed to match human performance and error distributions, and to have representations that are consistent with human behavior. A very deep net with 18 layers even outperformed humans at the highest variation level, using the most human-like representations.

  2. Computer aided method for colour calibration and analysis of digital rock photographs

    Directory of Open Access Journals (Sweden)

    Matic Potočnik

    2015-12-01

    Full Text Available The methods used in geology to determine colour and colour coverage are expensive, time consuming, and/ or subjective. Estimates of colour coverage can only be approximate since they are based on rough comparisonbased measuring etalons and subjective estimation, which is dependent upon the skill and experience of the person performing the estimation. We present a method which accelerates, simplifis, and objectifis these tasks using a computer application. It automatically calibrates the colours of a digital photo, and enables the user to read colour values and coverage, even after returning from fild work. Colour identifiation is based on the Munsell colour system. For the purposes of colour calibration we use the X-Rite ColorChecker Passport colour chart placed onto the photographed scene. Our computer application detects the ColorChecker colour chart, and fids a colour space transformation to calibrate the colour in the photo. The user can then use the application to read colours within selected points or regions of the photo. The results of the computerised colour calibration were compared to the reference values of the ColorChecker chart. The values slightly deviate from the exact values, but the deviation is around the limit of human capability for visual comparison. We have devised an experiment, which compares the precision of the computerised colour analysis and manual colour analysis performed on a variety of rock samples with the help of geology students using Munsell Rock-color Chart. The analysis showed that the precision of manual comparative identifiation on multicoloured samples is somewhat problematic, since the choice of representative colours and observation points for a certain part of a sample are subjective. The computer based method has the edge in verifibility and repeatability of the analysis since the application the original photo to be saved with colour calibration, and tagging of colouranalysed points and regions.

  3. Mapping human resources for eye health in 21 countries of sub-Saharan Africa: current progress towards VISION 2020

    Science.gov (United States)

    2014-01-01

    Background Development of human resources for eye health (HReH) is a major focus of the Global Action Plan 2014 to 2019 to reduce the prevalence of avoidable visual impairment by 25% by the year 2019. The eye health workforce is thought to be much smaller in sub-Saharan Africa than in other regions of the world but data to support this for policy-making is scarce. We collected HReH and cataract surgeries data from 21 countries in sub-Sahara to estimate progress towards key suggested population-based VISION 2020 HReH indicators and cataract surgery rates (CSR) in 2011. Methods Routinely collected data on practitioner and surgery numbers in 2011 was requested from national eye care coordinators via electronic questionnaires. Telephone and e-mail discussions were used to determine data collection strategies that fit the national context and to verify reported data quality. Information was collected on six practitioner cadres: ophthalmologists, cataract surgeons, ophthalmic clinical officers, ophthalmic nurses, optometrists and ‘mid-level refractionists’ and combined with publicly available population data to calculate practitioner to population ratios and CSRs. Associations with development characteristics were conducted using Wilcoxon rank sum tests and Spearman rank correlations. Results HReH data was not easily available. A minority of countries had achieved the suggested VISION 2020 targets in 2011; five countries for ophthalmologists/cataract surgeons, four for ophthalmic nurses/clinical officers and two for CSR. All countries were below target for optometrists, even when other cadres who perform refractions as a primary duty were considered. The regional (sample) ratio for surgeons (ophthalmologists and cataract surgeons) was 2.9 per million population, 5.5 for ophthalmic clinical officers and nurses, 3.7 for optometrists and other refractionists, and 515 for CSR. A positive correlation between GDP and CSR as well as many practitioner ratios was observed

  4. Relationship between Human Immunodeficiency Virus Neuroretinal Disorder and Vision-Specific Quality of Life among People with AIDS.

    Science.gov (United States)

    Ashraf, Davin C; May, K Patrick; Holland, Gary N; Van Natta, Mark L; Wu, Albert W; Thorne, Jennifer E; Jabs, Douglas A

    2015-12-01

    Some human immunodeficiency virus (HIV)-infected individuals have evidence of optic nerve or retinal dysfunction that manifests as decreased contrast sensitivity, even with good best-corrected visual acuity (BCVA). This condition, termed HIV-related neuroretinal disorder (HIV-NRD), is a risk factor for vision impairment (BCVA HIV-NRD on vision-specific quality of life (QOL). Cross-sectional analysis of data from a prospective, observational study. Individuals from the Longitudinal Study of the Ocular Complications of AIDS cohort who completed the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25), had BCVA of 20/40 or better, and had no evidence of ocular opportunistic infection or cataract. We compared QOL by HIV-NRD status, adjusting for potential confounding variables, using multiple linear regression. Among those with HIV-NRD, we assessed the relationship between VFQ-25 and the logarithm of contrast sensitivity (logCS), using Spearman correlation. We defined a minimum clinically important difference (MCID) as 1 standard error of measurement from a well-characterized, historical population of individuals with a variety of ophthalmic disorders. Subscales and composite VFQ-25 scores (0 = worst, 100 = best). A total of 813 individuals met study criteria. Those with HIV-NRD (n = 39 [4.8%]) had a lower mean composite score than those without HIV-NRD (81 vs. 89; P = 0.0002) and lower mean scores in the following subscales: near activities (77 vs. 86; P = 0.004), distance activities (85 vs. 91; P = 0.01), social functioning (89 vs. 96; P = 0.0005), mental health (75 vs. 87; P = 0.0001), dependency (81 vs. 94; P differences for each of these subscales met criteria for MCID. Among those with HIV-NRD, there was a positive correlation between logCS and composite score (r = 0.36; 95% confidence interval, 0.04-0.60). HIV-NRD has a statistically significant and clinically meaningful association with decreased vision-specific QOL among people with AIDS and

  5. Annotating Coloured Petri Nets

    DEFF Research Database (Denmark)

    Lindstrøm, Bo; Wells, Lisa Marie

    2002-01-01

    Coloured Petri nets (CP-nets) can be used for several fundamentally different purposes like functional analysis, performance analysis, and visualisation. To be able to use the corresponding tool extensions and libraries it is sometimes necessary to include extra auxiliary information in the CP-ne...... a certain use of the CP-net. We define the semantics of annotations by describing a translation from a CP-net and the corresponding annotation layers to another CP-net where the annotations are an integrated part of the CP-net....... a method which makes it possible to associate auxiliary information, called annotations, with tokens without modifying the colour sets of the CP-net. Annotations are pieces of information that are not essential for determining the behaviour of the system being modelled, but are rather added to support...

  6. The Colours of Smell

    OpenAIRE

    Moeran, Brian

    2011-01-01

    This paper examines perfume advertising within the overall context of theoretical approaches to the study of smell. Pointing out that smell is marked by a paucity of language, it proceeds to examine how smell is represented in perfume advertisements. Based on an analysis of more than 250 ads worldwide, the paper asks if there are any consistent relations between language, colours and smell materials, as well as between models’ poses, seasons, and classes of perfume (floral, oriental, woody, a...

  7. Robust Real-time Vision-based Human Detection and Tracking

    OpenAIRE

    Leu, Adrian

    2014-01-01

    In the last couple of decades technology has made its way into our everyday lives including our homes, our offices and the vehicles we use for travelling. Many modern devices interact with humans in a more or less intuitive way and some of them use cameras for observing or interacting with humans. Nevertheless, teaching a machine to detect humans in an image or a video is a very difficult task. There are many aspects that contribute to the complexity of this task, such as the many variations ...

  8. [Genetics of congenital color vision defects. I. Common types of color blindness].

    Science.gov (United States)

    Krawczyński, M R

    1995-01-01

    Normal human colour vision is based on the presence of 3 kinds of cones containing 3 different visual pigments, sensitive to short (blue), middle (green) and long (red) wavelengths. Congenital defects of colour vision are based on handicap or total loss of these pigments' function, usually a result of changes in their coding genes. The common types of colour blindness, referred to red-green axis, are present in about 8% of males and 0.44% of females. 3/4 of them are deuteranopes or deuteranomalous trichromats and 1/4 of them are protanopes or protanomalous trichromats. All of them are inherited in X-linked recessive way. The genes have been already mapped and sequenced. The cause of the great majority of their changes is nonhomologous recombination, which produces a gene deletion or creates the red-green or green-red hybrid genes. The result of that is the production of visual pigment with partly or totally changed spectral sensitivity.

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

    Science.gov (United States)

    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.

  10. Micro Vision

    OpenAIRE

    Ohba, Kohtaro; OHARA, Kenichi

    2007-01-01

    In the field of the micro vision, there are few researches compared with macro environment. However, applying to the study result for macro computer vision technique, you can measure and observe the micro environment. Moreover, based on the effects of micro environment, it is possible to discovery the new theories and new techniques.

  11. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Science.gov (United States)

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual systems can extract depth from such zones. I review the relevant human perception literature in this area, and show some recent data aimed at quantifying the perception of depth from monocular zones. The paper finishes with a discussion of the potential importance of considering monocular zones, for stereo display technology and depth compression algorithms.

  12. Fusion of colour and monochromatic images with edge emphasis

    Directory of Open Access Journals (Sweden)

    Rade M. Pavlović

    2014-02-01

    Full Text Available We propose a novel method to fuse true colour images with monochromatic non-visible range images that seeks to encode important structural information from monochromatic images efficiently but also preserve the natural appearance of the available true chromacity information. We utilise the β colour opponency channel of the lαβ colour as the domain to fuse information from the monochromatic input into the colour input by the way of robust grayscale fusion. This is followed by an effective gradient structure visualisation step that enhances the visibility of monochromatic information in the final colour fused image. Images fused using this method preserve their natural appearance and chromacity better than conventional methods while at the same time clearly encode structural information from the monochormatic input. This is demonstrated on a number of well-known true colour fusion examples and confirmed by the results of subjective trials on the data from several colour fusion scenarios. Introduction The goal of image fusion can be broadly defined as: the representation of visual information contained in a number of input images into a single fused image without distortion or loss of information. In practice, however, a representation of all available information from multiple inputs in a single image is almost impossible and fusion is generally a data reduction task.  One of the sensors usually provides a true colour image that by definition has all of its data dimensions already populated by the spatial and chromatic information. Fusing such images with information from monochromatic inputs in a conventional manner can severely affect natural appearance of the fused image. This is a difficult problem and partly the reason why colour fusion received only a fraction of the attention than better behaved grayscale fusion even long after colour sensors became widespread. Fusion method Humans tend to see colours as contrasts between opponent

  13. Human duodenal phase III migrating motor complex activity is predominantly antegrade, as revealed by high-resolution manometry and colour pressure plots.

    Science.gov (United States)

    Andrews, J M; O'donovan, D G; Hebbard, G S; Malbert, C H; Doran, S M; Dent, J

    2002-08-01

    Abstract Late phase III migrating motor complex activity has been said to be primarily retroperistaltic but has not been assessed with high resolution manometry or three-dimensional colour pressure plots (pressure/time/distance). Duodenal phase III was examined in healthy young volunteers (seven male, two female) with a 20-lumen assembly. With the most proximal sidehole in the distal antrum, after a 4.5-cm interval 18 sideholes at 1.5-cm intervals spanned the duodenum with a final sidehole 3 cm beyond. Fasting pressures were recorded until phase III occurred. Comparisons were made between proximal (P) and distal (D) duodenum during early (E) (first 0.5-1 min) and late (L) (last 0.5-1 min) phase III. With colour pressure analysis, 121 of 180 pressure wave (PW) sequences were purely antegrade, two purely retrograde and 57 bidirectional. Ten of fifty-seven bidirectional PW sequences were complex, branching to become two separate sequences. Bidirectional sequences occurred more frequently in late than early phase III (L 43 vs. E 14 of 57), but their occurrence did not differ between proximal and distal duodenum (P31 vs. D 24 of 57). Antegrade propagation velocity was faster in late compared with early phase III (L 28.50 vs. E 17.05 mm s(-1); P = 0.006), but did not differ between proximal and distal duodenum. Colour pressure analysis also indicated an intermittent segmental pattern to phase III, with each subject exhibiting a change in velocity or direction, or a relative failure of peristalsis somewhere along the duodenum during part of phase III. Duodenal phase III is not homogenous and, in contrast with previous studies, does not primarily constitute a retroperistaltic pump. Colour pressure analysis is useful in interpreting intraluminal pressure profiles and may improve the sensitivity and specificity of clinical studies.

  14. A study of women heterozygous for colour deficiencies.

    Science.gov (United States)

    Jordan, G; Mollon, J D

    1993-07-01

    We have examined the colour vision of 43 female subjects in the age range 30-59 yr of whom 31 were obligate carriers of various forms of colour deficiency and the rest were women who had no known colour-deficient relatives. In the case of all the carriers we established the phenotypes of their colour-deficient sons. As a group, carriers made significantly more errors on the Ishihara plates and showed enlarged matching ranges on the Nagel anomaloscope, but we could not replicate earlier reports of increased error scores on the Farnsworth-Munsell 100-Hue test or of systematic shifts in Rayleigh match mid-points. We did find that the colour matches of carriers of deuteranomaly were significantly displaced from those of normals in a ratio-matching task in which a mixture of 546 and 600 nm was matched with a mixture of 570 and 690 nm. Owing to X-chromosome inactivation, women who are heterozygous for anomalous trichromacy ought to have at least four types of cone in their retinae and we ask whether this affords them an extra dimension of colour vision, by analogy to New World monkeys where heterozygous females gain trichromacy in a basically dichromatic species. Many carriers of anomalous trichromacy exhibited no evidence for tetrachromacy, in that they accepted large-field Rayleigh matches following a rod bleach and they were unable to set unique matches in our ratio-matching task. However, eight carriers of anomalous trichromacy--and no other subject--refused large-field Rayleigh matches; and we found one carrier of deuteranomaly who was apparently able to make unique matches in the ratio-matching task.

  15. Colour mimicry and sexual deception by Tongue orchids (Cryptostylis).

    Science.gov (United States)

    Gaskett, A C; Herberstein, M E

    2010-01-01

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic (Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids' single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids' bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects' innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

  16. Colour mimicry and sexual deception by Tongue orchids ( Cryptostylis)

    Science.gov (United States)

    Gaskett, A. C.; Herberstein, M. E.

    2010-01-01

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic ( Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids’ single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids’ bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects’ innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

  17. Unravelling 21st Century Riddles – Universal Network Visions from a Human Perspective

    NARCIS (Netherlands)

    Baken, N.; Van Belleghem, N.; Van Boven, E.; De Korte, A.

    2006-01-01

    Networks are omnipresent and universal. Mankind, for example, forms a social network. Today, information and communications technology (ICT) exponentially accelerates the interaction between the human nodes of this global social network. In that way, ICT appears to evoke a phase transformation,

  18. Extending the Humanistic Vision: Toward a Humanities Foundation for the Counseling Profession

    Science.gov (United States)

    Hansen, James T.

    2012-01-01

    Founding humanists argued that counseling should be ideologically grounded in the humanities. Currently, professional counseling culture is largely structured by scientific assumptions, which, the author maintains, have had a detrimental impact on the profession. Specific recommendations for shifting professional counseling culture to a humanities…

  19. Development of a vision non-contact sensing system for telerobotic applications

    Science.gov (United States)

    Karkoub, M.; Her, M.-G.; Ho, M.-I.; Huang, C.-C.

    2013-08-01

    The study presented here describes a novel vision-based motion detection system for telerobotic operations such as distant surgical procedures. The system uses a CCD camera and image processing to detect the motion of a master robot or operator. Colour tags are placed on the arm and head of a human operator to detect the up/down, right/left motion of the head as well as the right/left motion of the arm. The motion of the colour tags are used to actuate a slave robot or a remote system. The determination of the colour tags' motion is achieved through image processing using eigenvectors and colour system morphology and the relative head, shoulder and wrist rotation angles through inverse dynamics and coordinate transformation. A program is used to transform this motion data into motor control commands and transmit them to a slave robot or remote system through wireless internet. The system performed well even in complex environments with errors that did not exceed 2 pixels with a response time of about 0.1 s. The results of the experiments are available at: http://www.youtube.com/watch?v=yFxLaVWE3f8 and http://www.youtube.com/watch?v=_nvRcOzlWHw

  20. Quality indexing by machine vision during fermentation in black tea manufacturing

    Science.gov (United States)

    Borah, S.; Bhuyan, M.

    2003-04-01

    Although the organoleptic method of tea testing has been traditionally used for quality monitoring, an alternative way by machine vision may be advantageous. Although, the three main quality descriptors estimate the overall quality of made-tea, viz., strength, briskness and brightness of tea liquor, the exact colour detection in fermenting process leads to a good quality-monitoring tool. The use of digital image processing technique for this purpose is reported to play an effective role towards the production of good quality tea though it is not the only quality determining parameter. In this paper, it has been tried to compare the contribution of the chemical constituents towards the final product with the visual appearance in the processing stage by imaging. The use of machine intelligence supports the process somewhat invariantly in comparison to the human decision and colorimetric approach. The captured images are processed for colour matching with a standard image database using HSI colour model. The application of colour dissimilarity and perceptron learning for the standard images and the test images is ensured. Moreover, the performance of the system is being tried to correlate with the decision made by the organoleptic panel assigned for the tea testing and chemical test results on the final product. However, it should be noted that the optimized result could be achieved only when the other quality parameters such as withering, flavour (aroma) detection, drying status etc. are properly maintained.

  1. Data-driven analysis of analogous brain networks in monkeys and humans during natural vision.

    Science.gov (United States)

    Mantini, Dante; Corbetta, Maurizio; Romani, Gian Luca; Orban, Guy A; Vanduffel, Wim

    2012-11-15

    Inferences about functional correspondences between functional networks of human and non-human primates largely rely on proximity and anatomical expansion models. However, it has been demonstrated that topologically correspondent areas in two species can have different functional properties, suggesting that anatomy-based approaches should be complemented with alternative methods to perform functional comparisons. We have recently shown that comparative analyses based on temporal correlations of sensory-driven fMRI responses can reveal functional correspondent areas in monkeys and humans without relying on spatial assumptions. Inter-species activity correlation (ISAC) analyses require the definition of seed areas in one species to reveal functional correspondences across the cortex of the same and other species. Here we propose an extension of the ISAC method that does not rely on any seed definition, hence a method void of any spatial assumption. Specifically, we apply independent component analysis (ICA) separately to monkey and human data to define species-specific networks of areas with coherent stimulus-related activity. Then, we use a hierarchical cluster analysis to identify ICA-based ISAC clusters of monkey and human networks with similar timecourses. We implemented this approach on fMRI data collected in monkeys and humans during movie watching, a condition that evokes widespread sensory-driven activity throughout large portions of the cortex. Using ICA-based ISAC, we detected seven monkey-human clusters. The timecourses of several clusters showed significant correspondences either with the motion energy in the movie or with eye-movement parameters. Five of the clusters spanned putative homologous functional networks in either primary or extrastriate visual regions, whereas two clusters included higher-level visual areas at topological locations that are not predicted by cortical surface expansion models. Overall, our ICA-based ISAC analysis complemented

  2. Vision of Space Exploration Possibilities and limits of a human space conquest.

    Science.gov (United States)

    Zelenyi, Lev

    Few generations of a schoolboys, which later become active and productive space researchers, have been brought up on a science fiction books. These books told us about travels to other Galaxies with velocities larger then velocity of light, meetings with friendly aliens (necessarily with communistic mentalities in Soviet Union books), star wars with ugly space monsters (in the western hemisphere books), etc. Beginning of Space age (4/10/1957) opened the door to a magic box, full of scientific discoveries, made mostly by robotic satellites and spacecraft. However, already the first human space trips clearly demonstrated that space is vigorously hostile to a human beings. Space medicine during the years since Gagarin flight, made an outstanding progress in supporting human presence at orbital stations, but the radiation hazards and problem of hypomagnetism are still opened and there is no visible path to their solution. So the optimistic slogan of 60-ies “Space is Our Place” is not supported by an almost half a century practice. Space never will be a comfortable place for soft and vulnerable humans? There is a general consensus that man will be on Mars during this century (or even its first part). This is very difficult but task it seems to be realistic after the significant advance of modern technologies will be made. But, is there any real need for humans to travel beyond the Mars orbit or to the inner regions of the Solar system? Will the age of Solar system exploration comes to its logical as it was described by Stanislav Lem in his famous book “Return from stars”? The author of this talk has more questions than answers, and thinks that PEX1 Panel on Exploration is just a right place to discuss these usually by passed topics.

  3. Nonrepetitive Colouring via Entropy Compression

    CERN Document Server

    Dujmović, Vida; Wood, David R

    2011-01-01

    A vertex colouring of a graph is \\emph{nonrepetitive} if there is no path whose first half receives the same sequence of colours as the second half. A graph is nonrepetitively $k$-choosable if given lists of at least $k$ colours at each vertex, there is a nonrepetitive colouring such that each vertex is coloured from its own list. It is known that every graph with maximum degree $\\Delta$ is $c\\Delta^2$-choosable, for some constant $c$. We prove this result with $c=4$. We then prove that every subdivision of a graph with sufficiently many division vertices per edge is nonrepetitively 6-choosable. The proofs of both these results are based on the Moser-Tardos entropy-compression method, and a recent extension by Grytczuk, Kozik and Micek for the nonrepetitive choosability of paths. Finally, we prove that every graph with pathwidth $k$ is nonrepetitively ($2k^2+6k+1$)-colourable.

  4. Pale blue dot a vision of the human future in space

    CERN Document Server

    Sagan, Carl

    1994-01-01

    In Cosmos, the late astronomer Carl Sagan cast his gaze over the magnificent mystery of the Universe and made it accessible to millions of people around the world. Now in this stunning sequel, Carl Sagan completes his revolutionary journey through space and time. Future generations will look back on our epoch as the time when the human race finally broke into a radically new frontier--space. In Pale Blue Dot Sagan traces the spellbinding history of our launch into the cosmos and assesses the future that looms before us as we move out into our own solar system and on to distant galaxies beyond. The exploration and eventual settlement of other worlds is neither a fantasy nor luxury, insists Sagan, but rather a necessary condition for the survival of the human race.

  5. Measuring human emotions with modular neural networks and computer vision based applications

    Directory of Open Access Journals (Sweden)

    Veaceslav Albu

    2015-05-01

    Full Text Available This paper describes a neural network architecture for emotion recognition for human-computer interfaces and applied systems. In the current research, we propose a combination of the most recent biometric techniques with the neural networks (NN approach for real-time emotion and behavioral analysis. The system will be tested in real-time applications of customers' behavior for distributed on-land systems, such as kiosks and ATMs.

  6. Theory of colours

    CERN Document Server

    Goethe, Johann Wolfgang von

    2006-01-01

    The wavelength theory of light and color had been firmly established by the time the great German poet published his Theory of Colours in 1810. Nevertheless, Goethe believed that the theory derived from a fundamental error, in which an incidental result was mistaken for a elemental principle. Far from affecting a knowledge of physics, he maintained that such a background would inhibit understanding. The conclusions Goethe draws here rest entirely upon his personal observations.This volume does not have to be studied to be appreciated. The author's subjective theory of colors permits him to spe

  7. Colours in Amish Quilts

    OpenAIRE

    Homlong, Siri

    2015-01-01

    The Amish religious movement have its roots in the Protestant Reformation in the 16th century. The Amish people are anabaptists and have strict rules for their way of life. They were persecuted in Europe and Amish groups emigrated to Pennsylvania. Today the most traditional part of the movement – the Old Amish People – lives in Lancaster County west of Philadelphia, USA. This paper describs a study of the colours in Old Amish Quilts, traditional Amish patchwork quilts used as bed covers. The ...

  8. Computer vision

    Science.gov (United States)

    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.

  9. Global skin colour prediction from DNA.

    Science.gov (United States)

    Walsh, Susan; Chaitanya, Lakshmi; Breslin, Krystal; Muralidharan, Charanya; Bronikowska, Agnieszka; Pospiech, Ewelina; Koller, Julia; Kovatsi, Leda; Wollstein, Andreas; Branicki, Wojciech; Liu, Fan; Kayser, Manfred

    2017-07-01

    Human skin colour is highly heritable and externally visible with relevance in medical, forensic, and anthropological genetics. Although eye and hair colour can already be predicted with high accuracies from small sets of carefully selected DNA markers, knowledge about the genetic predictability of skin colour is limited. Here, we investigate the skin colour predictive value of 77 single-nucleotide polymorphisms (SNPs) from 37 genetic loci previously associated with human pigmentation using 2025 individuals from 31 global populations. We identified a minimal set of 36 highly informative skin colour predictive SNPs and developed a statistical prediction model capable of skin colour prediction on a global scale. Average cross-validated prediction accuracies expressed as area under the receiver-operating characteristic curve (AUC) ± standard deviation were 0.97 ± 0.02 for Light, 0.83 ± 0.11 for Dark, and 0.96 ± 0.03 for Dark-Black. When using a 5-category, this resulted in 0.74 ± 0.05 for Very Pale, 0.72 ± 0.03 for Pale, 0.73 ± 0.03 for Intermediate, 0.87±0.1 for Dark, and 0.97 ± 0.03 for Dark-Black. A comparative analysis in 194 independent samples from 17 populations demonstrated that our model outperformed a previously proposed 10-SNP-classifier approach with AUCs rising from 0.79 to 0.82 for White, comparable at the intermediate level of 0.63 and 0.62, respectively, and a large increase from 0.64 to 0.92 for Black. Overall, this study demonstrates that the chosen DNA markers and prediction model, particularly the 5-category level; allow skin colour predictions within and between continental regions for the first time, which will serve as a valuable resource for future applications in forensic and anthropologic genetics.

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

    Science.gov (United States)

    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.

  11. Colour constancy across the life span: evidence for compensatory mechanisms.

    Science.gov (United States)

    Wuerger, Sophie

    2013-01-01

    It is well known that the peripheral visual system declines with age: the yellowing of the lens causes a selective reduction of short-wavelength light and sensitivity losses occur in the cone receptor mechanisms. At the same time, our subjective experience of colour does not change with age. The main purpose of this large-scale study (n = 185) covering a wide age range of colour-normal observers (18-75 years of age) was to assess the extent to which the human visual system is able to compensate for the changes in the optical media and at which level of processing this compensation is likely to occur. We report two main results: (1) Supra-threshold parafoveal colour perception remains largely unaffected by the age-related changes in the optical media (yellowing of the lens) whereas our ability to discriminate between small colour differences is compromised with an increase in age. (2) Significant changes in colour appearance are only found for unique green settings under daylight viewing condition which is consistent with the idea that the yellow-blue mechanism is most affected by an increase in age due to selective attenuation of short-wavelength light. The data on the invariance of hue perception, in conjunction with the age-related decline in chromatic sensitivity, provides evidence for compensatory mechanisms that enable colour-normal human observers a large degree of colour constancy across the life span. These compensatory mechanisms are likely to originate at cortical sites.

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

    Science.gov (United States)

    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.

  13. What Is Low Vision?

    Science.gov (United States)

    ... Condition Eye Health Low Vision What Is Low Vision? What "Low Vision" Means Signs and Symptoms of ... Services The Low Vision Pilot Project What "Low Vision" Means As we age, our eyes change too. ...

  14. All Vision Impairment

    Science.gov (United States)

    ... Home > Statistics and Data > All Vision Impairment All Vision Impairment Vision Impairment Defined Vision impairment is defined as the ... Ethnicity 2010 U.S. Age-Specific Prevalence Rates for Vision Impairment by Age and Race/Ethnicity Table for ...

  15. Healthy Living, Healthy Vision

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  16. Pregnancy and Your Vision

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  17. Class Separation Improvements in Pixel Classification Using Colour Injection

    Science.gov (United States)

    Blanco, Edward; Mazo, Manuel; Bergasa, Luis; Palazuelos, Sira; Rodríguez, Jose; Losada, Cristina; Martín, Jose

    2010-01-01

    This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS) sub-space. The authors propose to inject (add) a colour vector in the Red Green Blue (RGB) space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2) space) is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required. PMID:22163628

  18. Class Separation Improvements in Pixel Classification Using Colour Injection

    Directory of Open Access Journals (Sweden)

    Jose Martín

    2010-08-01

    Full Text Available This paper presents an improvement in the colour image segmentation in the Hue Saturation (HS sub-space. The authors propose to inject (add a colour vector in the Red Green Blue (RGB space to increase the class separation in the HS plane. The goal of the work is the development of an algorithm to obtain the optimal colour vector for injection that maximizes the separation between the classes in the HS plane. The chromatic Chrominace-1 Chrominance-2 sub-space (of the Luminance Chrominace-1 Chrominance-2 (YC1C2 space is used to obtain the optimal vector to add. The proposal is applied on each frame of a colour image sequence in real-time. It has been tested in applications with reduced contrast between the colours of the background and the object, and particularly when the size of the object is very small in comparison with the size of the captured scene. Numerous tests have confirmed that this proposal improves the segmentation process, considerably reducing the effects of the variation of the light intensity of the scene. Several tests have been made in skin segmentation in applications for sign language recognition via computer vision, where an accurate segmentation of hands and face is required.

  19. Investigating binocular summation in human vision using complementary fused external noise

    Science.gov (United States)

    Howell, Christopher L.; Olson, Jeffrey T.

    2016-05-01

    The impact noise has on the processing of visual information at various stages within the human visual system (HVS) is still an open research area. To gain additional insight, twelve experiments were administered to human observers using sine wave targets to determine their contrast thresholds. A single frame of additive white Gaussian noise (AWGN) and its complement were used to investigate the effect of noise on the summation of visual information within the HVS. A standard contrast threshold experiment served as the baseline for comparisons. In the standard experiment, a range of sine wave targets are shown to the observers and their ability to detect the targets at varying contrast levels were recorded. The remaining experiments added some form of noise (noise image or its complement) and/or an additional sine wave target separated between one to three octaves to the test target. All of these experiments were tested using either a single monitor for viewing the targets or with a dual monitor presentation method for comparison. In the dual monitor experiments, a ninety degree mirror was used to direct each target to a different eye, allowing for the information to be fused binocularly. The experiments in this study present different approaches for delivering external noise to the HVS, and should allow for an improved understanding regarding how noise enters the HVS and what impact noise has on the processing of visual information.

  20. NICE: A Computational Solution to Close the Gap from Colour Perception to Colour Categorization.

    Science.gov (United States)

    Parraga, C Alejandro; Akbarinia, Arash

    2016-01-01

    The segmentation of visible electromagnetic radiation into chromatic categories by the human visual system has been extensively studied from a perceptual point of view, resulting in several colour appearance models. However, there is currently a void when it comes to relate these results to the physiological mechanisms that are known to shape the pre-cortical and cortical visual pathway. This work intends to begin to fill this void by proposing a new physiologically plausible model of colour categorization based on Neural Isoresponsive Colour Ellipsoids (NICE) in the cone-contrast space defined by the main directions of the visual signals entering the visual cortex. The model was adjusted to fit psychophysical measures that concentrate on the categorical boundaries and are consistent with the ellipsoidal isoresponse surfaces of visual cortical neurons. By revealing the shape of such categorical colour regions, our measures allow for a more precise and parsimonious description, connecting well-known early visual processing mechanisms to the less understood phenomenon of colour categorization. To test the feasibility of our method we applied it to exemplary images and a popular ground-truth chart obtaining labelling results that are better than those of current state-of-the-art algorithms.

  1. A simplified method for generation of pseudo natural colours from colour infrared aerial photos

    DEFF Research Database (Denmark)

    Knudsen, Thomas; Olsen, Brian Pilemann

    In spite of their high potential for automated discrimination between vegetation and human made objects, colour-infrared (CIR) aerial photos have not been in widespread use for traditional photogrammetric mapping. This is probably due to their awkward colour representation invalidating the visual...... analytical experience of the stereo analysts doing the actual registration of the topographical data. In this paper, we present a method for generating pseudo natural colour (PNC) representations from CIR photos. This enables the combination of automated vegetation discrimination with traditional manual...... mapping methods. The method presented is a dramatic simplification of a recently published method, going from a 7 step to a 2 step procedure. The first step is a classification of the input image into 4 domains, based on simple thresholding of a vegetation index and a saturation measure for each pixel...

  2. Across light: through colour

    Science.gov (United States)

    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.

  3. A colourful clock.

    Directory of Open Access Journals (Sweden)

    Hester C van Diepen

    2015-05-01

    Full Text Available 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.

  4. A colourful clock.

    Science.gov (United States)

    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.

  5. Colour doppler ultrasonography and sclerosing therapy in diagnosis and treatment of tendinopathy in horses-a research model for human medicine

    DEFF Research Database (Denmark)

    Boesen, Morten Ilum; Nanni, Simone; Langberg, Henning

    2007-01-01

    Sclerosing therapy has in recent studies showed promising results in patients with clinically and ultrasonographically diagnosed tendinosis in Achilles and patellar tendons. The aim of this investigation was to study the presence of intratendinous colour Doppler (CD) flow in horses with clinically...... unilateral chronic tendinosis in the forelimbs were examinated with both grey-scale ultrasonography (US) and CD. The horses were to be euthanised according to standard procedure is such cases. The US findings were used for guidance of sclerosing therapy. All horses showed abnormal findings on US, especially...

  6. Linguistic determinants of word colouring in grapheme-colour synaesthesia.

    Science.gov (United States)

    Simner, Julia; Glover, Louise; Mowat, Alice

    2006-02-01

    Previous studies of grapheme-colour synaesthesia have suggested that words tend to be coloured by their initial letter or initial vowel (e.g., Baron-Cohen et al., 1993; Ward et al., 2005). We examine this assumption in two ways. First, we show that letter position and syllable stress have been confounded, such that the initial letters of a word are often in stressed position (e.g., 'wo-man, 'ta-ble, 'ha-ppy). With participant JW, we separate these factors (e.g., with stress homographs such as 'con-vict vs. con-'vict) and show that the primary determinant of word colour is syllable stress, with only a secondary influence of letter position. We show that this effect derives from conceptual rather than perceptual stress, and that the effect is more prominent for synaesthetes whose words are coloured by vowels than by consonants. We examine, too, the time course of word colour generation. Slower colour naming occurs for spoken versus written stimuli, as we might expect from the additional requirement of grapheme conversion in the former. Reaction time data provide evidence, too, of incremental processing, since word colour is generated faster when the dominant grapheme is flagged early rather than late in the spoken word. Finally, we examine the role of non-dominant graphemes in word colouring and show faster colour naming when later graphemes match the dominant grapheme (e.g., ether) compared to when they do not (e.g., ethos). Taken together, our findings suggest that words are coloured incrementally by a process of competition between constituent graphemes, in which stressed graphemes and word-initial graphemes are disproportionately weighted.

  7. Reversible colour change in Arthropoda.

    Science.gov (United States)

    Umbers, Kate D L; Fabricant, Scott A; Gawryszewski, Felipe M; Seago, Ainsley E; Herberstein, Marie E

    2014-11-01

    The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry.

  8. A Vision Chip,

    Science.gov (United States)

    1981-05-01

    the time-derivative of the image at the point is also represented. The development of the theory of edge detection was motivated by the need to...E. (1979) " Theory of Edge Detection ," MIT Al Lab. Memo 518. Marr, D. & Poggio, T. (1977) "A Theory of Human Stereo Vision," MIT Al Lab. Memo 451

  9. Colour changes by laser irradiation of reddish building limestones

    Science.gov (United States)

    Grossi, C. M.; Benavente, D.

    2016-10-01

    We have used X-ray photoelectron spectroscopy (XPS) as a novel method to investigate the causes of colour changes in a reddish limestone under irradiation by a Q-switched Nd:YAG 1064 nm laser. We irradiated clean dry and wet surfaces of Pidramuelle Roja, a building stone frequently used in the Asturian heritage, at fluences ranging from 0.12 to 1.47 J cm-2. We measured the colour coordinates and undertook XPS analysis of the state of oxidation of iron both before and after irradiation. Visible colour changes and potential aesthetic damage occurred on dry surfaces from a fluence of 0.31 J cm-2, with the stone showing a greening effect and very intense darkening. The colour change on dry surfaces was considerably higher than on wet surfaces, which at the highest fluence (1.47 J cm-2) was also above the human visual detection threshold. The use of XPS demonstrated that the change in colour (chroma and hue) is associated with a reduction in the iron oxidation state on dry surfaces during laser irradiation. This points out to a potential routinary use of XPS to analyse causes of colour changes during laser cleaning in other types of coloured building stones.

  10. Natural Blue Food Colour

    DEFF Research Database (Denmark)

    Roda-Serrat, Maria Cinta

    In recent years, there has been a growing tendency to avoid the use of artificial colorants and additives in food products, especially after some studies linked their consumption with behavioural changes in children. However, the incorporation of colorants from natural origin remains a challenge...... for food technologists, as these are typically less vivid and less stable than their synthetic alternatives. Regarding blue colorants, phycocyanins from cyanobacteria are currently in the spotlight as promising new natural blue colorants. Phycocyanins are proteins which blue colour results from...... the presence of the chromophore phycocyanobilin (PCB), a covalently attached linear tetrapyrrole. The applications of phycocyanins as food colorants are however limited, as they show poor stability in certain conditions of pH, light and temperature. Cleavage of PCB from the protein followed by careful product...

  11. Genetics of colouration in birds.

    Science.gov (United States)

    Roulin, Alexandre; Ducrest, Anne-Lyse

    2013-01-01

    Establishing the links between phenotype and genotype is of great importance for resolving key questions about the evolution, maintenance and adaptive function of phenotypic variation. Bird colouration is one of the most studied systems to investigate the role of natural and sexual selection in the evolution of phenotypic diversity. Given the recent advances in molecular tools that allow discovering genetic polymorphisms and measuring gene and protein expression levels, it is timely to review the literature on the genetics of bird colouration. The present study shows that melanin-based colour phenotypes are often associated with mutations at melanogenic genes. Differences in melanin-based colouration are caused by switches of eumelanin to pheomelanin production or by changes in feather keratin structure, melanoblast migration and differentiation, as well as melanosome structure. Similar associations with other types of colourations are difficult to establish, because our knowledge about the molecular genetics of carotenoid-based and structural colouration is quasi inexistent. This discrepancy stems from the fact that only melanin-based colouration shows pronounced heritability estimates, i.e. the resemblance between related individuals is usually mainly explained by genetic factors. In contrast, the expression of carotenoid-based colouration is phenotypically plastic with a high sensitivity to variation in environmental conditions. It therefore appears that melanin-based colour traits are prime systems to understand the genetic basis of phenotypic variation. In this context, birds have a great potential to bring us to new frontiers where many exciting discoveries will be made on the genetics of phenotypic traits, such as colouration. In this context, a major goal of our review is to suggest a number of exciting future avenues.

  12. The secret world of shrimps: polarisation vision at its best

    CERN Document Server

    Kleinlogel, Sonja

    2008-01-01

    Animal vision spans a great range of complexity, with systems evolving to detect variations in optical 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. 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 \\emph{Gonodactylus smithii} measures the exact components required. This vision provides optimal contrast-enhancement, and precise determination of polarisation with no confusion-states or neutral-points--significant advantages. We emphasise that linear and circular polarisation vision are not different modalities--both are necessary for optimal polarisation vis...

  13. The N-terminal region of centrosomal protein 290 (CEP290) restores vision in a zebrafish model of human blindness.

    Science.gov (United States)

    Baye, Lisa M; Patrinostro, Xiaobai; Swaminathan, Svetha; Beck, John S; Zhang, Yan; Stone, Edwin M; Sheffield, Val C; Slusarski, Diane C

    2011-04-15

    The gene coding for centrosomal protein 290 (CEP290), a large multidomain protein, is the most frequently mutated gene underlying the non-syndromic blinding disorder Leber's congenital amaurosis (LCA). CEP290 has also been implicated in several cilia-related syndromic disorders including Meckel-Gruber syndrome, Joubert syndrome, Senor-Loken syndrome and Bardet-Biedl syndrome (BBS). In this study, we characterize the developmental and functional roles of cep290 in zebrafish. An antisense oligonucleotide [Morpholino (MO)], designed to generate an altered cep290 splice product that models the most common LCA mutation, was used for gene knockdown. We show that cep290 MO-injected embryos have reduced Kupffer's vesicle size and delays in melanosome transport, two phenotypes that are observed upon knockdown of bbs genes in zebrafish. Consistent with a role in cilia function, the cep290 MO-injected embryos exhibited a curved body axis. Patients with LCA caused by mutations in CEP290 have reduced visual perception, although they present with a fully laminated retina. Similarly, the histological examination of retinas from cep290 MO-injected zebrafish revealed no gross lamination defects, yet the embryos had a statistically significant reduction in visual function. Finally, we demonstrate that the vision impairment caused by the disruption of cep290 can be rescued by expressing only the N-terminal region of the human CEP290 protein. These data reveal that a specific region of the CEP290 protein is sufficient to restore visual function and this region may be a viable gene therapy target for LCA patients with mutations in CEP290.

  14. Developmental disorders of vision.

    Science.gov (United States)

    Galaburda, Albert M; Duchaine, Bradley C

    2003-08-01

    This review of developmental disorders of vision focuses on only a few of the many disorders that disrupt visual development. Given the enormity of the human visual system in the primate brain and complexity of visual development, however, there are likely hundreds or thousands of types of disorders affecting high-level vision. The rapid progress seen in developmental dyslexia and WMS demonstrates the possibilities and difficulties inherent in researching such disorders, and the authors hope that similar progress will be made for congenital prosopagnosia and other disorders in the near future.

  15. Challenges towards realization of health care sector goals of Tanzania development vision 2025: training and deployment of graduate human resource for health.

    Science.gov (United States)

    Siril, Nathanael; Kiwara, Angwara; Simba, Daud

    2013-06-01

    Human resource for health (HRH) is an essential building block for effective and efficient health care system. In Tanzania this component is faced by many challenges which in synergy with others make the health care system inefficient. In vision 2025 the country recognizes the importance of the health care sector in attaining quality livelihood for its citizens. The vision is in its 13th year since its launch. Given the central role of HRH in attainment of this vision, how the HRH is trained and deployed deserves a deeper understanding. To analyze the factors affecting training and deployment process of graduate level HRH of three core cadres; Medical Doctors, Doctor of Dental Surgery and Bachelor of Pharmacy towards realization of development vision 2025. Explorative study design in five training institutions for health and Ministry of Health and Social Welfare (MoHSW) headquarters utilizing in-depth interviews, observations and review of available documents methodology. The training Institutions which are cornerstone for HRH training are understaffed, underfunded (donor dependent), have low admitting capacities and lack co-ordination with other key stakeholders dealing with health. The deployment of graduate level HRH is affected by; limited budget, decision on deployment handled by another ministry rather than MoHSW, competition between health care sector and other sectors and lack of co-ordination between employer, trainers and other key health care sector stakeholders. Awareness on vision 2025 is low in the training institutions. For the vision 2025 health care sector goals to be realized well devised strategies on raising its awareness in the training institutions is recommended. Quality livelihood as stated in vision 2025 will be a forgotten dream if the challenges facing the training and deployment of graduate level HRH will not be addressed timely. It is the authors' view that reduction of donor dependency syndrome, extension of retirement age for academic

  16. Pseudo natural colour aerial imagery for urban and suburban mapping

    DEFF Research Database (Denmark)

    Knudsen, Thomas

    2005-01-01

    Due to their near-infrared data channel, digital airborne four-channel imagers provide a potentially good discrimination between vegetation and human-made materials, which is very useful in automated mapping. Due to their red, green and blue data channels, they also provide natural colour images......, which are very useful in traditional (manual) mapping. In this paper, an algorithm is described which provides an approximation to the spectral capabilities of the four-channel imagers by using a colour-infrared aerial photo as input. The algorithm is tailored to urban/suburban surroundings, where...... the quality of the generated (pseudo) natural colour images are fully acceptable for manual mapping. This brings the combined availability of near-infrared and (pseudo) natural colours within reach for mapping projects based on traditional photogrammetry, which is valuable since traditional analytical cameras...

  17. Colour reconnection in WW events

    CERN Document Server

    D'Hondt, J

    2003-01-01

    Preliminary results are presented for a measurement of the kappa parameter used in the JETSET SK-I model of colour reconnection in W /sup +/W/sup -/ to qq'qq' events at LEP2. An update on the investigation of colour reconnection effects in hadronic decays of W pairs, using the particle flow in DELPHI is presented. A second method is based on the observation that two different m/sub W/ estimators have different sensitivity to the parametrised colour reconnection effect. Hence the difference between them is an observable with information content about kappa. (6 refs).

  18. Colour anomia resulting from weakened short-term colour memory. A case study.

    Science.gov (United States)

    Davidoff, J B; Ostergaard, A L

    1984-06-01

    A patient exhibited marked colour anomia without object anomia, but was able to point to named colours. Five experiments were conducted to investigate his immediate colour memory. It was concluded that his colour anomia was the result of an impaired short-term memory deficit specific to colour. Temporary activation of specific entries in the colour lexicon enabled pointing and even naming to take place. A general model incorporating all forms of colour anomia is presented.

  19. The dual rod system of amphibians supports colour discrimination at the absolute visual threshold

    Science.gov (United States)

    Yovanovich, Carola A. M.; Koskela, Sanna M.; Nevala, Noora; Kondrashev, Sergei L.

    2017-01-01

    The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts. In neither task was there any indication of rod-based colour discrimination. By contrast, frogs performing phototactic jumping were able to distinguish blue from green light down to the absolute visual threshold, where vision relies only on rod signals. The remarkable sensitivity of this mechanism comparing signals from the two spectrally different rod types approaches theoretical limits set by photon fluctuations and intrinsic noise. Together, the results indicate that different pathways are involved in processing colour cues depending on the ecological relevance of this information for each task. This article is part of the themed issue ‘Vision in dim light’. PMID:28193811

  20. Alternative to colour feature classification using colour contrast ocurrence matrix

    Science.gov (United States)

    Martínez, R. A.; Richard, N.; Fernandez, C.

    2015-04-01

    Texture discrimination was the second more important task studied after colour perception and characterization. Nevertheless, colour texture assessment and characterization was few studied and no vector processing was proposed to assess this important visual information. In this work we show the construction of a new vector that integrates fully the information of texture and color. This vector is based on Julesz psico-physics conjectures and the Haralick cooccurrence matrix. A colour texture image in the CIEL*a* b* colour space is characterizing in a 3D matrix, from which it is possible to visually some variations in chromaticity. The performance of this vector had evaluated in tasks of classification in front of other developments that mix the texture and colour information. The colour contrast occurrence matrix (C2O) has the best classification rates in three of the four image database evaluated as OUTEX, VISTEX, STEX and ALOT. C2O texture classification was evaluated in front of co-occurrence matrix (GLMC), run-length matrix (RLM) and local binary patterns (LBP) approaches.

  1. Optimal colour quality of LED clusters based on memory colours.

    Science.gov (United States)

    Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

    2011-03-28

    The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant.

  2. Vision Loss, Sudden

    Science.gov (United States)

    ... of age-related macular degeneration. Spotlight on Aging: Vision Loss in Older People Most commonly, vision loss ... Some Causes and Features of Sudden Loss of Vision Cause Common Features* Tests Sudden loss of vision ...

  3. Healthy Vision Tips

    Science.gov (United States)

    ... NEI for Kids > Healthy Vision Tips All About Vision About the Eye Ask a Scientist Video Series ... Links to More Information Optical Illusions Printables Healthy Vision Tips Healthy vision starts with you! Use these ...

  4. Colour Separation and Aversion

    Directory of Open Access Journals (Sweden)

    Sarah M Haigh

    2012-05-01

    Full Text Available Aversion to achromatic patterns is well documented but relatively little is known about discomfort from chromatic patterns. Large colour differences are uncommon in the natural environment and deviation from natural statistics makes images uncomfortable (Fernandez and Wilkins 2008, Perception, 37(7, 1098–113; Juricevic et al 2010, Perception, 39(7, 884–899. We report twelve studies documenting a linear increase in aversion to chromatic square-wave gratings as a function of the separation in UCS chromaticity between the component bars, independent of their luminance contrast. Two possible explanations for the aversion were investigated: (1 accommodative response, or (2 cortical metabolic demand. We found no correlation between chromaticity separation and accommodative lag or variance in lag, measured using an open-field autorefractor. However, near infrared spectroscopy of the occipital cortex revealed a larger oxyhaemoglobin response to patterns with large chromaticity separation. The aversion may be cortical in origin and does not appear to be due to accommodation.

  5. BRIEF REPORT: The colour relaxation equation

    Science.gov (United States)

    Xiaofei, Zhang; Jiarong, Li

    1996-03-01

    Colour diffusion in quark - gluon plasma (QGP) is investigated from the transport equations of QGP. The pure non-Abelian collision term describing the colour diffusion in QGP is obtained, the expression for colour relaxation time is derived and the physical picture of the colour diffusion in QGP is shown.

  6. A new universal colour image fidelity metric

    NARCIS (Netherlands)

    Toet, A.; Lucassen, M.P.

    2003-01-01

    We extend a recently introduced universal grayscale image quality index to a newly developed perceptually decorrelated colour space. The resulting colour image fidelity metric quantifies the distortion of a processed colour image relative to its original version. We evaluated the new colour image fi

  7. Structural colours through photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    McPhedran, R.C.; Nicorovici, N.A.; McKenzie, D.R.; Rouse, G.W.; Botten, L.C.; Welch, V.; Parker, A.R.; Wohlgennant, M.; Vardeny, V

    2003-10-01

    We discuss two examples of living creatures using photonic crystals to achieve iridescent colouration. The first is the sea mouse (Aphroditidae, Polychaeta), which has a hexagonal close packed structure of holes in its spines and lower-body felt, while the second is the jelly fish Bolinopsis infundibulum, which has an oblique array of high index inclusions in its antennae. We show by measurements and optical calculations that both creatures can achieve strong colours despite having access only to weak refractive index contrast.

  8. COLOUR IMAGE REPRESENTION OF MULTISPECTRAL IMAGE FUSION

    Directory of Open Access Journals (Sweden)

    Preema Mole

    2016-07-01

    Full Text Available The availability of imaging sensors operating in multiple spectral bands has led to the requirement of image fusion algorithms that would combine the image from these sensors in an efficient way to give an image that is more perceptible to human eye. Multispectral Image fusion is the process of combining images optically acquired in more than one spectral band. In this paper, we present a pixel-level image fusion that combines four images from four different spectral bands namely near infrared(0.76-0.90um, mid infrared(1.55-1.75um,thermal- infrared(10.4-12.5um and mid infrared(2.08-2.35um to give a composite colour image. The work coalesces a fusion technique that involves linear transformation based on Cholesky decomposition of the covariance matrix of source data that converts multispectral source images which are in grayscale into colour image. This work is composed of different segments that includes estimation of covariance matrix of images, cholesky decomposition and transformation ones. Finally, the fused colour image is compared with the fused image obtained by PCA transformation.

  9. Colour Day: an innovative project

    CERN Document Server

    Staff Association

    2016-01-01

    This year, the Children’s Day-Care Centre (EVE) and School works on the theme of colours. Every class has their own project revolving around this common theme. The class of Claire, Sandrine and Nadia, introduced a monthly “Colour Day”. The objective of this day is to offer children different activities (arts and crafts, baking, etc.) designed around a specific colour. The children get a chance to decorate their classroom and learn in many different ways inspired by the colours blue, red, and many others. The parents are also called to contribute and invited to dress their children in the colour of the day. In September, we discovered the colour blue, in October it was time for red, and in mid-November yellow will brighten up our structure. Everyone plays along, making this a very festive day for us all. On Tuesday, 20 September, we saw the whole School turn blue! We were all dressed in blue and we made blue paintings, too! We made beautiful artwork inspired by artists like Ma...

  10. Blindness and vision loss

    Science.gov (United States)

    ... means you cannot see anything and DO NOT see light. (Most people who use the term "blindness" mean ... the vision loss. For long-term vision loss, see a low-vision specialist, who can help you learn to care for yourself and ... of vision; No light perception (NLP); Low vision; Vision loss and blindness ...

  11. Visions and visioning in foresight activities

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard; Grosu, Dan

    2007-01-01

    The paper discusses the roles of visioning processes and visions in foresight activities and in societal discourses and changes parallel to or following foresight activities. The overall topic can be characterised as the dynamics and mechanisms that make visions and visioning processes work...... or not work. The theoretical part of the paper presents an actor-network theory approach to the analyses of visions and visioning processes, where the shaping of the visions and the visioning and what has made them work or not work is analysed. The empirical part is based on analyses of the roles of visions...... and visioning processes in a number of foresight processes from different societal contexts. The analyses have been carried out as part of the work in the COST A22 network on foresight. A vision is here understood as a description of a desirable or preferable future, compared to a scenario which is understood...

  12. A Robust Skin Colour Segmentation Using Bivariate Pearson Type IIαα (Bivariate Beta) Mixture Model

    OpenAIRE

    B.N.Jagadesh; Srinivasa Rao, K.; Ch.Satyanarayana

    2012-01-01

    Probability distributions formulate the basic framework for developing several segmentation algorithms. Among the various segmentation algorithms, skin colour segmentation is one of the most important algorithms for human computer interaction. Due to various random factors influencing the colour space, there does not exist a unique algorithm which serve the purpose of all images. In this paper a novel and new skin colour segmentation algorithms is proposed based on bivariate Pearson type I...

  13. The influence of colours on the purchase decision making process when developing sustainable products

    OpenAIRE

    Boris Jurič; Dijana Vuković; Branka Šuput

    2014-01-01

    Since ancient times human beings have been surrounded by colours and their influences on every aspect of their daily life. Consciously or subconsciously they have used colours to communicate with each other, to project the image of themselves to the others or in order to decorate their environment, to feed themselves and to produce the general feeling of comfort. The aim was to carry out consumer behaviour research on a random sample of 200 respondents about the influence of colours on the de...

  14. Colour and pattern composition to blend objects into a natural environment

    CSIR Research Space (South Africa)

    Baumbach, J

    2008-06-01

    Full Text Available ”. The human cognitive system is, according to Kosslynn (1995), a very opportunistic system. Depending on the task, clues provided and the observer’s abilities, different kinds of information in the scene are exploited for interpretation. Figure 1 shows... on the perceived colour. Colours with low chromaticity (more neutral/grey) are especially prone to contextual perceptions. One of the most striking examples is the coloured cube, developed by Lotto and Purves (2000). 3. CAMOUFLAGE PATTERNS In order...

  15. Industrial vision

    DEFF Research Database (Denmark)

    Knudsen, Ole

    1998-01-01

    of an implementation in real production environments. The theory for projection of world points into images is concentrated upon the direct linear transformation (DLT), also called the Extended Pinhole model, and the stability of this method. A complete list of formulas for calculating all parameters in the model...... is present ed, and the variability of the parameters is examined and described. The concept of using CAD together with vision information is based on the fact that all items processed at OSS have an associated complete 3D CAD model that is accessible at all production states. This concept gives numerous...... possibilities for using vision in applications which otherwise would be very difficult to automate. The requirement for low tolerances in production is, despite the huge dimensions of the items involved, extreme. This fact makes great demands on the ability to do robust sub pixel estimation. A new method based...

  16. Pleiades Visions

    Science.gov (United States)

    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.

  17. Machine Vision Giving Eyes to Robots. Resources in Technology.

    Science.gov (United States)

    Technology Teacher, 1990

    1990-01-01

    This module introduces machine vision, which can be used for inspection, robot guidance and part sorting. The future for machine vision will include new technology and will bring vision systems closer to the ultimate vision processor, the human eye. Includes a student quiz, outcomes, and activities. (JOW)

  18. Cartesian visions.

    Science.gov (United States)

    Fara, Patricia

    2008-12-01

    Few original portraits exist of René Descartes, yet his theories of vision were central to Enlightenment thought. French philosophers combined his emphasis on sight with the English approach of insisting that ideas are not innate, but must be built up from experience. In particular, Denis Diderot criticised Descartes's views by describing how Nicholas Saunderson--a blind physics professor at Cambridge--relied on touch. Diderot also made Saunderson the mouthpiece for some heretical arguments against the existence of God.

  19. Lambda Vision

    Science.gov (United States)

    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.

  20. Artificial vision.

    Science.gov (United States)

    Zarbin, M; Montemagno, C; Leary, J; Ritch, R

    2011-09-01

    A number treatment options are emerging for patients with retinal degenerative disease, including gene therapy, trophic factor therapy, visual cycle inhibitors (e.g., for patients with Stargardt disease and allied conditions), and cell transplantation. A radically different approach, which will augment but not replace these options, is termed neural prosthetics ("artificial vision"). Although rewiring of inner retinal circuits and inner retinal neuronal degeneration occur in association with photoreceptor degeneration in retinitis pigmentosa (RP), it is possible to create visually useful percepts by stimulating retinal ganglion cells electrically. This fact has lead to the development of techniques to induce photosensitivity in cells that are not light sensitive normally as well as to the development of the bionic retina. Advances in artificial vision continue at a robust pace. These advances are based on the use of molecular engineering and nanotechnology to render cells light-sensitive, to target ion channels to the appropriate cell type (e.g., bipolar cell) and/or cell region (e.g., dendritic tree vs. soma), and on sophisticated image processing algorithms that take advantage of our knowledge of signal processing in the retina. Combined with advances in gene therapy, pathway-based therapy, and cell-based therapy, "artificial vision" technologies create a powerful armamentarium with which ophthalmologists will be able to treat blindness in patients who have a variety of degenerative retinal diseases.

  1. Colour preference between adults and children during a dental treatment session.

    Science.gov (United States)

    Oner Ozdas, Didem; Kazak, Magrur

    2017-02-01

    It is evidently shown that colour has physical, psychological and sociological effects on human beings. There are many studies showing the effects of colours on brain activity. Colour preferences may change from childhood to adulthood and are significantly different in various age groups. The aim of this study was to evaluate the adults and children in their preference for mouthrinses in various colours under stress condition during a dental treatment session. 240 adults and 263 children were included in the study. Three transparent cups were filled with water, two of which were coloured green/pink rinsing by dissolving a tablet in the water. Cups were placed near the dental unit. During dental treatment sessions, patients were told to rinse their mouth with whichever cup they preferred. Preferred colour of cup, gender and age of patient, number of sessions were recorded. Data were statistically analysed by SPSS 15.0 programme and chi-square tests. Half of all cases preferred water. In adults, while females statistically significantly preferred water, males chose cups with coloured contents (padults preferred more than one rinsing solution in a dental treatment session. Children mostly preferred water. Even if adults preferred cups with coloured contents in multi-dental treatment sessions, children regularly preferred water (padults and children. Female adults and children were not interested in trying colourful mouthrinses, while male adults were curious about trying colourful mouthrinses during dental treatment sessions under stress condition. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Computer Vision Systems

    Science.gov (United States)

    Gunasekaran, Sundaram

    Food quality is of paramount consideration for all consumers, and its importance is perhaps only second to food safety. By some definition, food safety is also incorporated into the broad categorization of food quality. Hence, the need for careful and accurate evaluation of food quality is at the forefront of research and development both in the academia and industry. Among the many available methods for food quality evaluation, computer vision has proven to be the most powerful, especially for nondestructively extracting and quantifying many features that have direct relevance to food quality assessment and control. Furthermore, computer vision systems serve to rapidly evaluate the most readily observable foods quality attributes - the external characteristics such as color, shape, size, surface texture etc. In addition, it is now possible, using advanced computer vision technologies, to “see” inside a food product and/or package to examine important quality attributes ordinarily unavailable to human evaluators. With rapid advances in electronic hardware and other associated imaging technologies, the cost-effectiveness and speed of computer vision systems have greatly improved and many practical systems are already in place in the food industry.

  3. Colour, Luminance and Crowding

    Directory of Open Access Journals (Sweden)

    BJ Jennings

    2013-10-01

    Full Text Available Three experiments were performed to assess the effect backgrounds have on object discrimination. Experiment 1 investigated the discrimination of foveally presented Gaborised objects and non-objects with and without a surrounding background. Thresholds were obtained by modulating the Gabor patches in 7 different directions, either isolating the L-M, S-(L+M and L+M geniculate mechanisms, or stimulating these mechanisms in combination. The spacing between background Gabor elements and the object contour was chosen so as to not cause crowding, on the basis of previously published work with luminance stimuli. No differences were found between the Michelson contrasts required for threshold with or without a background, except when signals in the S-(L+M and L+M were combined. The signals were combined at an elevation of 30° in DKL colour space, which resulted in a mixture with a proportionally strong chromatic signal. Experiment 2 investigated this finding further using three background conditions: no background, a sparse background and a densely populated background. Object vs. non-object discrimination thresholds were obtained for the L+M and S-(L+M isolating directions, along with two conditions that combined them at DKL luminance elevations of 30° and 60°. In the 60° combination, the proportion of the chromatic signal was lower than in the 30° combination. Thresholds were found to be largely stable across chromatic and luminance conditions and background class, again with the exception of the combination at 30° elevation. The final experiment examined Gabor orientation discrimination over the same conditions as experiment 2 using a classical crowding paradigm, with a peripheral target and a set of three target-flanker separations. Crowding was most pronounced in the 30° combination. We conclude that when S-(L+M signals above a certain level are combined with luminance signals, an increase in crowding results. This is likely to underlie the

  4. The Developmental Stage of Adult Human Stem Cell-Derived Retinal Pigment Epithelium Cells Influences Transplant Efficacy for Vision Rescue

    Directory of Open Access Journals (Sweden)

    Richard J. Davis

    2017-07-01

    Full Text Available Age-related macular degeneration (AMD is a common cause of central visual loss in the elderly. Retinal pigment epithelial (RPE cell loss occurs early in the course of AMD and RPE cell transplantation holds promise to slow disease progression. We report that subretinal transplantation of RPE stem cell (RPESC-derived RPE cells (RPESC-RPE preserved vision in a rat model of RPE cell dysfunction. Importantly, the stage of differentiation that RPESC-RPE acquired prior to transplantation influenced the efficacy of vision rescue. Whereas cells at all stages of differentiation tested rescued photoreceptor layer morphology, an intermediate stage of RPESC-RPE differentiation obtained after 4 weeks of culture was more consistent at vision rescue than progeny that were differentiated for 2 weeks or 8 weeks of culture. Our results indicate that the developmental stage of RPESC-RPE significantly influences the efficacy of RPE cell replacement, which affects the therapeutic application of these cells for AMD.

  5. Colour Symbols in Mari Songs

    Directory of Open Access Journals (Sweden)

    Natalia Glukhova

    2016-06-01

    Full Text Available This article presents a system of colour symbols in Mari folk songs based on the results of a multifold investigation. The research was carried out with the help of a complex technique applied to 2100 songs from different song collections. Mari colour symbols have never before been the object of research. The process of investigation included several steps. The most important of these was the semantic analysis that helped to discern 2000 mentions of four main spectre colours as well as white, black, silver, and golden. Quantitative data evaluation singled out a dominant group by a dichotomous method, applying the principle of simple majority employed in mathematical statistics. The same technique divided the other colour symbols into complementary, auxiliary, and insignificant groups. The results of an investigation into ethnic symbology are also shown graphically. The main reconstructed meanings of colour in the analysed songs denote such emotions as joy, wonder, astonishment, grief, melancholy, some aesthetic ideals, ethical vices, as well as people’s character and appearance.

  6. The colour of gender stereotyping.

    Science.gov (United States)

    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. ©2011 The British Psychological Society.

  7. Cross-Modal Associations in Synaesthesia: Vowel Colours in the Ear of the Beholder

    Directory of Open Access Journals (Sweden)

    Anja Moos

    2014-04-01

    Full Text Available Human speech conveys many forms of information, but for some exceptional individuals (synaesthetes, listening to speech sounds can automatically induce visual percepts such as colours. In this experiment, grapheme–colour synaesthetes and controls were asked to assign colours, or shades of grey, to different vowel sounds. We then investigated whether the acoustic content of these vowel sounds influenced participants' colour and grey-shade choices. We found that both colour and grey-shade associations varied systematically with vowel changes. The colour effect was significant for both participant groups, but significantly stronger and more consistent for synaesthetes. Because not all vowel sounds that we used are “translatable” into graphemes, we conclude that acoustic–phonetic influences co-exist with established graphemic influences in the cross-modal correspondences of both synaesthetes and non-synaesthetes.

  8. Cross-modal associations in synaesthesia: Vowel colours in the ear of the beholder.

    Science.gov (United States)

    Moos, Anja; Smith, Rachel; Miller, Sam R; Simmons, David R

    2014-01-01

    Human speech conveys many forms of information, but for some exceptional individuals (synaesthetes), listening to speech sounds can automatically induce visual percepts such as colours. In this experiment, grapheme-colour synaesthetes and controls were asked to assign colours, or shades of grey, to different vowel sounds. We then investigated whether the acoustic content of these vowel sounds influenced participants' colour and grey-shade choices. We found that both colour and grey-shade associations varied systematically with vowel changes. The colour effect was significant for both participant groups, but significantly stronger and more consistent for synaesthetes. Because not all vowel sounds that we used are "translatable" into graphemes, we conclude that acoustic-phonetic influences co-exist with established graphemic influences in the cross-modal correspondences of both synaesthetes and non-synaesthetes.

  9. 基于视觉的人体运动分析综述%A Survey of Vision-Based Human Motion Analysis

    Institute of Scientific and Technical Information of China (English)

    阮涛涛; 姚明海; 瞿心昱; 楼中望

    2011-01-01

    Vision-based human motion analysis is receiving increasing attention from computer vision researchers.It becomes the hotspot of the field of image analysis, psychology and artificial intelligence.It has a wide application in intelligent video surveillance, virtual reality, user interfaces and motion analysis.In this paper, moving target detection,classification, tracking and human action recognition are overviewed.We analyze some problems and challenges.Finally, some research directions in the future are discussed.%基于视觉的人运动分析越来越受到计算机视觉领域研究者的广泛关注,它成为图像分析、心理学、人工智能等领域的研究热点,在智能视频监控、虚拟现实、用户接口、运动分析等方面有着广泛的应用.从运动目标检测、运动目标分类、人体运动跟踪、人体行为识别与描述四个环节综述了人体运动分析的研究现状,分析了存在的一些问题和未来的研究发展方向.

  10. A METHOD FOR RECORDING AND VIEWING STEREOSCOPIC IMAGES IN COLOUR USING MULTICHROME FILTERS

    DEFF Research Database (Denmark)

    2000-01-01

    in a conventional stereogram recorded of the scene. The invention makes use of a colour-based encoding technique and viewing filters selected so that the human observer receives, in one eye, an image of nearly full colour information, in the other eye, an essentially monochrome image supplying the parallactic...

  11. Determining the Appropriate Font Size, and Use of Colour and Contrast for Underwater Displays

    Science.gov (United States)

    2008-04-01

    stimulus ( Kantowitz and Sorkin, 1983). Colour contrast refers to the ratio of hue and saturation of the colour when compared to the hue and...11. Kantowitz , B.H. and Sorkin, R.D. (1983) Human factors: Understanding people- system relationships. John Wiley, New York, p.124. 12. Luria

  12. Pediatric Low Vision

    Science.gov (United States)

    ... Asked Questions Español Condiciones Chinese Conditions Pediatric Low Vision What is Low Vision? Partial vision loss that cannot be corrected causes ... and play. What are the signs of Low Vision? Some signs of low vision include difficulty recognizing ...

  13. Low Vision FAQs

    Science.gov (United States)

    ... de los Ojos Cómo hablarle a su oculista Low Vision FAQs What is low vision? Low vision is a visual impairment, not ... person’s ability to perform everyday activities. What causes low vision? Low vision can result from a variety ...

  14. Color vision.

    Science.gov (United States)

    Gegenfurtner, Karl R; Kiper, Daniel C

    2003-01-01

    Color vision starts with the absorption of light in the retinal cone photoreceptors, which transduce electromagnetic energy into electrical voltages. These voltages are transformed into action potentials by a complicated network of cells in the retina. The information is sent to the visual cortex via the lateral geniculate nucleus (LGN) in three separate color-opponent channels that have been characterized psychophysically, physiologically, and computationally. The properties of cells in the retina and LGN account for a surprisingly large body of psychophysical literature. This suggests that several fundamental computations involved in color perception occur at early levels of processing. In the cortex, information from the three retino-geniculate channels is combined to enable perception of a large variety of different hues. Furthermore, recent evidence suggests that color analysis and coding cannot be separated from the analysis and coding of other visual attributes such as form and motion. Though there are some brain areas that are more sensitive to color than others, color vision emerges through the combined activity of neurons in many different areas.

  15. Colour and inclusivity: a visual communication design project with older people.

    Science.gov (United States)

    da Silva, Fernando Moreira

    2012-01-01

    In an ideal world, inclusive products and services would be the standard and not the exception. This paper presents a systematic approach to an overlap between Visual Communication Design, Printed Colour and Inclusive Design, for older people, with the aim to develop of a set of research-based ageing and ergonomics-centred communication design guidelines and recommendations for printed material (analogical displays). The approach included an initial extensive literature review in the area of colour, older people and ergonomics issues and vision common diseases, communication design. The second phase was the implementation of an experiment to measure the different colour experiences of the participants in two sample groups (one in UK and another one in Portugal), using printed material, to find out the colours one should use in analogical communication material, being aware of the colour contrast importance (foreground versus background) and the difficulties experienced by older people to read and understand lettering, signs. As main contribution of this research project, we developed a set of guidelines and recommendations based on the reviewed literature and the sample groups' findings, trying to demonstrate the importance of these guidelines when conceiving a new communicational design project in a way this project will achieve vision comfort and understandability, especially for older people, in an inclusive design perspective.

  16. INNOVATION OF ENTERPRISE VISION TOWARD SOCIAL RESPONSIBILITY

    Directory of Open Access Journals (Sweden)

    Tjaša Štrukelj

    2012-12-01

    Full Text Available Businesses need new bases and methods taking in account new values, culture, ethics, and norms (VCEN of humans, leading both humans and businesses to their own requisite holism. This covers also enterprise governance and management and their predisposition to (responsible enterprise vision (and resulting enterprise policy we studied. Thus we are researching the formation and development of enterprise vision, the period and wholeness of which are relative. In our discussion we originated in different definitions of vision andwe showed a possible development path for it, in order to direct vision towards social responsibility (SR in enterprise behaviour.

  17. The secret world of shrimps: polarisation vision at its best.

    Directory of Open Access Journals (Sweden)

    Sonja Kleinlogel

    Full Text Available 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.

  18. Neuroimaging: a scanner, colourfully.

    Science.gov (United States)

    Roiser, Jonathan P; Rees, Geraint

    2012-04-10

    Two recent studies report changes in human brain responses after exposure to psilocybin, the active ingredient of hallucinogenic mushrooms. Psilocybin increased sensory cortex responses during emotional recollection, but decreased resting-state blood flow in prefrontal cortex, with potential implications for treating depression.

  19. Digieye Application In Cotton Colour Measurement

    Directory of Open Access Journals (Sweden)

    Matusiak Małgorzata

    2015-06-01

    Full Text Available Colour is one of the most important properties of cotton raw materials. It helps in determining and classifying the quality of fibres according to the Universal Cotton Standards. Organoleptic and instrumental techniques are applied to assess the color of cotton. Worldwide, the colour parameters of cotton are measured by the High Volume Instrument (HVI, which provides information on reflectance (Rd and yellowness (+b that is specific for cotton, but are not the typical and globally recognized colour characteristics. Usually, worldwide, the colour of textile products and other goods is assessed utilizing the spectrophotometer, which provides the colour data that is widely recognized and accepted by the CIE L*a*b* colour space. This paper discusses utilizing the DigiEye system to measure the colour parameters of cotton samples and compares the results with the colour parameters from the HVI.

  20. Special Section on Coloured Petri Nets

    DEFF Research Database (Denmark)

    1998-01-01

    Special section on coloured Petri nets, their basic concepts, analysis methods, tool support and industrial applications.......Special section on coloured Petri nets, their basic concepts, analysis methods, tool support and industrial applications....

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

    Science.gov (United States)

    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

  2. Impairments to Vision

    Science.gov (United States)

    ... an external Non-Government web site. Impairments to Vision Normal Vision Diabetic Retinopathy Age-related Macular Degeneration In this ... pictures, fixate on the nose to simulate the vision loss. In diabetic retinopathy, the blood vessels in ...

  3. Color vision test

    Science.gov (United States)

    ... present from birth) color vision problems: Achromatopsia -- complete color blindness , seeing only shades of gray Deuteranopia -- difficulty telling ... Vision test - color; Ishihara color vision test Images Color blindness tests References Bowling B. Hereditary fundus dystrophies. In: ...

  4. Monitoring dental erosion by colour measurement : An in vitro study

    NARCIS (Netherlands)

    Krikken, J. B.; Zijp, J. R.; Huysmans, M. C. D. N. J. M.

    2008-01-01

    Objectives: The aim of this study was to develop a method to monitor dental erosion by evaluation of the colour change of teeth as a function of enamel loss, and to evaluate the reproducibility of the method used. Methods: Light reflectance spectra of 12 extracted human incisors were measured using

  5. Phenomenology of high colour fermions

    Energy Technology Data Exchange (ETDEWEB)

    Lust, D.; Streng, K.H.; Papantonopoulos, E.; Zoupanos, G.

    1986-04-28

    We present the phenomenological consequences of a dynamical scenario for electroweak symmetry breaking and generation of fermion masses, involving the presence of fermions which transform under high colour representations. Particular emphasis is given to the predictions for rare processes and to the possible signals in present and future machines. (orig.).

  6. Chromomagnetic catalysis of colour superconductivity

    CERN Document Server

    Zhukovskij, V C; Klimenko, K G; Ehbert, D

    2001-01-01

    The effect of the chromomagnetic field on the phase structure of the Namby - Jona-Lasinio expanded model with two quarks aromas is studied. It is shown that certain types of the chromomagnetic fields induce spontaneous violation of the colour, chiral or both symmetries simultaneously, depending on the ratio between the quarks interaction constants in the q-barq- and qq-channels

  7. Skills Underlying Coloured Progressive Matrices

    Science.gov (United States)

    Kirby, J. R.; Das, J. P.

    1978-01-01

    Raven's Coloured Progressive Matrices and a battery of ability tests were administered to a sample of 104 male fourth graders for purposes of investigating the relationships between 2 previously identified subscales of the Raven and the ability tests. Results indicated use of a spatial strategy and to a lesser extent, use of reasoning, indicating…

  8. Colour reconnection at LEP2

    CERN Document Server

    Abreu, P

    2002-01-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, ALEPH, DELPHI, L3 and OPAL, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method (D. Duchesneau, (2001)), are yet inconclusive. (22 refs).

  9. Pseudo natural colour aerial imagery for urban and suburban mapping

    DEFF Research Database (Denmark)

    Knudsen, Thomas

    2005-01-01

    Due to their near-infrared data channel, digital airborne four-channel imagers provide a potentially good discrimination between vegetation and human-made materials, which is very useful in automated mapping. Due to their red, green and blue data channels, they also provide natural colour images......, which are very useful in traditional (manual) mapping. In this paper, an algorithm is described which provides an approximation to the spectral capabilities of the four-channel imagers by using a colour-infrared aerial photo as input. The algorithm is tailored to urban/suburban surroundings, where...

  10. Artificial vision.

    Science.gov (United States)

    Humayun, M S; de Juan, E

    1998-01-01

    Outer retinal degenerations such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) lead to blindness because of photoreceptor degeneration. To test whether controlled electrical stimulation of the remaining retinal neurons could provide form vision, we electrically stimulated the inner retinal surface with micro-electrodes inserted through the sclera/eye wall of 14 of these patients (12 RP and 2 AMD). This procedure was performed in the operating room under local anaesthesia and all responses were recorded via a video camera mounted on the surgical microscope. Electrical stimulation of the inner retinal surface elicited visual perception of a spot of light (phosphene) in all subjects. This perception was retinotopically correct in 13 of 14 patients. In a resolution test in a subject with no light perception, the patient could resolve phosphenes at 1.75 degrees centre-to-centre distance (i.e. visual acuity compatible with mobility; Snellen visual acuity of 4/200).

  11. Basic design principles of colorimetric vision systems

    Science.gov (United States)

    Mumzhiu, Alex M.

    1998-10-01

    Color measurement is an important part of overall production quality control in textile, coating, plastics, food, paper and other industries. The color measurement instruments such as colorimeters and spectrophotometers, used for production quality control have many limitations. In many applications they cannot be used for a variety of reasons and have to be replaced with human operators. Machine vision has great potential for color measurement. The components for color machine vision systems, such as broadcast quality 3-CCD cameras, fast and inexpensive PCI frame grabbers, and sophisticated image processing software packages are available. However the machine vision industry has only started to approach the color domain. The few color machine vision systems on the market, produced by the largest machine vision manufacturers have very limited capabilities. A lack of understanding that a vision based color measurement system could fail if it ignores the basic principles of colorimetry is the main reason for the slow progress of color vision systems. the purpose of this paper is to clarify how color measurement principles have to be applied to vision systems and how the electro-optical design features of colorimeters have to be modified in order to implement them for vision systems. The subject of this presentation far exceeds the limitations of a journal paper so only the most important aspects will be discussed. An overview of the major areas of applications for colorimetric vision system will be discussed. Finally, the reasons why some customers are happy with their vision systems and some are not will be analyzed.

  12. Colorimetric measurements of iris colour and their significance in East Asian patients with skin cancer.

    Science.gov (United States)

    Kim, J W; Seo, S H; Kye, Y C; Ahn, H H

    2010-10-01

    A light-coloured iris is considered a risk factor for skin cancer in general. However, iris colour cannot be considered a plausible risk factor for skin cancer in East Asian populations because of the relative homogeneity of iris colours. Furthermore, subjective classifications of iris colour cannot distinguish between different East Asian individuals as to their likelihood of developing cancer. To measure human iris colours quantitatively and to assess the significances of iris colours with respect to skin cancer in Korean patients. Reference Commission Internationale d'Eclairage (CIE) L*a*b* coordinates on a ColorCheck chart were recorded using a reflectance spectrophotometer and compared with computed CIE L*a*b* coordinates from digital images to determine equations to calibrate CIE L*a*b* values. We then took iris images and measured iris colours and the colours of sun-exposed and sun-protected skin in 42 Korean patients with various cutaneous malignancies and nonmalignant dermatological diseases. Results were statistically analysed with regard to iris and skin colours in CIE L*a*b* coordinates. Patients with skin cancer had significantly lighter irises or higher L* values than dermatological patients without a malignancy (P = 0.02). Colour differences (ΔE*ab) between sun-exposed skin and sun-protected skin were greater in men (P skin cancer (P skins decreased with age (r = -0.32, P colour appears to be a possible skin cancer risk factor in East Asian populations. The larger colour differences seen between sun-protected and sun-exposed skin in men and in patients with skin cancer may have been due to chronic or excessive sun exposure. © 2009 The Author(s). Journal compilation © 2009 British Association of Dermatologists.

  13. Search for Colour Singlet and Colour Reconnection Effects in Hadronic Z Decays at LEP

    CERN Document Server

    Achard, P; Aguilar-Benítez, M; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Anderhub, H; Andreev, V P; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Bajo, A; Baksay, G; Baksay, L; Baldew, S V; Banerjee, S; Banerjee, Sw; Barczyk, A; Barillère, R; Bartalini, P; Basile, M; Batalova, N; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Bellucci, L; Berbeco, R; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Biasini, M; Biglietti, M; Biland, A; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böhm, A; Boldizsar, L; Borgia, B; Bottai, S; Bourilkov, D; Bourquin, Maurice; Braccini, S; Branson, J G; Brochu, F; Burger, J D; Burger, W J; Cai, X D; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada, M; Chamizo-Llatas, M; Chang, Y H; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chiefari, G; Cifarelli, Luisa; Cindolo, F; Clare, I; Clare, R; Coignet, G; Colino, N; Costantini, S; de la Cruz, B; Cucciarelli, S; van Dalen, J A; De Asmundis, R; Déglon, P L; Debreczeni, J; Degré, A; Dehmelt, K; Deiters, K; Della Volpe, D; Delmeire, E; Denes, P; De Notaristefani, F; De Salvo, A; Diemoz, M; Dierckxsens, M; Dionisi, C; Dittmar, M; Doria, A; Dova, M T; Duchesneau, D; Duda, M; Echenard, B; Eline, A; El-Hage, A; El-Mamouni, H; Engler, A; Eppling, F J; Extermann, P; Falagán, M A; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, M; Ferguson, T; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, F; Fisher, P H; Fisher, W; Fisk, I; Forconi, G; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gataullin, M; Gentile, S; Giagu, S; Gong, Z F; Grenier, G; Grimm, O; Grünewald, M W; Guida, M; van Gulik, R; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Hofer, H; Hohlmann, M; Holzner, G; Hou, S R; Hu, Y; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Käfer, D; Kaur, M; Kienzle-Focacci, M N; Kim, J K; Kirkby, Jasper; Kittel, E W; Klimentov, A; König, A C; Kopal, M; Koutsenko, V F; Kräber, M H; Krämer, R W; Krüger, A; Kunin, A; Ladrón de Guevara, P; Laktineh, I; Landi, G; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Le Goff, J M; Leiste, R; Levtchenko, M; Levchenko, P M; Li, C; Likhoded, S; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lü, Y S; Luci, C; Luminari, L; Lustermann, W; Ma Wen Gan; Malgeri, L; Malinin, A; Maña, C; Mans, J; Martin, J P; Marzano, F; Mazumdar, K; McNeil, R R; Mele, S; Merola, L; Meschini, M; Metzger, W J; Mihul, A; Milcent, H; Mirabelli, G; Mnich, J; Mohanty, G B; Muanza, G S; Muijs, A J M; Musicar, B; Musy, M; Nagy, S; Natale, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nisati, A; Novák, T; Nowak, H; Ofierzynski, R A; Organtini, G; Pal, I; Palomares, C; Paolucci, P; Paramatti, R; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Pedace, M; Pensotti, S; Perret-Gallix, D; Petersen, B; Piccolo, D; Pierella, F; Pioppi, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Pothier, J; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Rahaman, M A; Raics, P; Raja, N; Ramelli, R; Rancoita, P G; Ranieri, R; Raspereza, A V; Razis, P A; Ren, D; Rescigno, M; Reucroft, S; Riemann, S; Riles, K; Roe, B P; Romero, L; Rosca, A; Rosier-Lees, S; Roth, S; Rosenbleck, C; Rubio, J A; Ruggiero, G; Rykaczewski, H; Sakharov, A; Saremi, S; Sarkar, S; Salicio, J; Sánchez, E; Schäfer, C; Shchegelskii, V; Schopper, Herwig Franz; Schotanus, D J; Sciacca, C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shumilov, E; Shvorob, A V; Son, D; Souga, C; Spillantini, P; Steuer, M; Stickland, D P; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Sushkov, S; Suter, H; Swain, J D; Szillási, Z; Tang, X W; Tarjan, P; Tauscher, Ludwig; Taylor, L; Tellili, B; Teyssier, D; Timmermans, C; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tung, K L; Ulbricht, J; Valente, E; Van de Walle, R T; Vásquez, R; Veszpremi, V; Vesztergombi, G; Vetlitskii, I; Vicinanza, D; Viertel, Gert M; Villa, S; Vivargent, M; Vlachos, S; Vodopyanov, I; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Wadhwa, M; Wang, Q; Wang, X L; Wang, Z M; Weber, M; Wienemann, P; Wilkens, H; Wynhoff, S; Xia, L; Xu, Z Z; Yamamoto, J; Yang, B Z; Yang, C G; Yang, H J; Yang, M; Yeh, S C; Zalite, A; Zalite, Yu; Zhang, Z P; Zhao, J; Zhu, G Y; Zhu, R Y; Zhuang, H L; Zichichi, A; Zimmermann, B; Zöller, M

    2004-01-01

    A search is performed in symmetric 3-jet hadronic Z decay events for evidence of colour singlet production or colour reconnection effects. Asymmetries in the angular separation of particles are found to be sensitive indicators of such effects. Upper limits on the level of colour singlet production and colour reconnection effects are established for a variety of models.

  14. Biological Components of Colour Preference in Infancy

    Science.gov (United States)

    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. Colour in the eyes of insects

    NARCIS (Netherlands)

    Stavenga, D.G.

    Many insect species have darkly coloured eyes, but distinct colours or patterns are frequently featured. A number of exemplary cases of flies and butterflies are discussed to illustrate our present knowledge of the physical basis of eye colours, their functional background, and the implications for

  16. -Colour even Self-Inverse Compositions

    Indian Academy of Sciences (India)

    Yu-hong Guo

    2010-02-01

    An -colour even self-inverse composition is defined as an -colour self-inverse composition with even parts. In this paper, we get generating functions, explicit formulas and recurrence formulas for -colour even self-inverse compositions. One new binomial identity is also obtained.

  17. Colour in the eyes of insects

    NARCIS (Netherlands)

    Stavenga, D.G.

    2002-01-01

    Many insect species have darkly coloured eyes, but distinct colours or patterns are frequently featured. A number of exemplary cases of flies and butterflies are discussed to illustrate our present knowledge of the physical basis of eye colours, their functional background, and the implications for

  18. Biological Components of Colour Preference in Infancy

    Science.gov (United States)

    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…

  19. Evidence of basal temporo-occipital cortex involvement in stereoscopic vision in humans: a study with subdural electrode recordings.

    Science.gov (United States)

    Gonzalez, Francisco; Relova, José Luis; Prieto, Angel; Peleteiro, Manuel

    2005-01-01

    Stereoscopic vision is based on small differences in both retinal images known as retinal disparities. We investigated the cortical responses to retinal disparities in a patient suffering from occipital epilepsy by recording evoked potentials to random dot stereograms (RDS) from subdural electrodes placed in the parieto-occipito-temporal junction, medial surface of the occipital lobe (pericalcarine cortex) and basal surface of the occipital and temporal lobes (fusiform gyrus). Clear responses to disparity present in RDS were found in the fusiform cortex. We observed that the fusiform responses discriminate the onset from the offset of the stimulus, correlation from uncorrelation, and they show a longer latency than responses found in the pericalcarine cortex. Our findings indicate that the fusiform area is involved in the processing of the stereoscopic information and shows responses that suggest a high level of stereoscopic processing.

  20. A Fast Vision System for Soccer Robot

    Directory of Open Access Journals (Sweden)

    Tianwu Yang

    2012-01-01

    Full Text Available This paper proposes a fast colour-based object recognition and localization for soccer robots. The traditional HSL colour model is modified for better colour segmentation and edge detection in a colour coded environment. The object recognition is based on only the edge pixels to speed up the computation. The edge pixels are detected by intelligently scanning a small part of whole image pixels which is distributed over the image. A fast method for line and circle centre detection is also discussed. For object localization, 26 key points are defined on the soccer field. While two or more key points can be seen from the robot camera view, the three rotation angles are adjusted to achieve a precise localization of robots and other objects. If no key point is detected, the robot position is estimated according to the history of robot movement and the feedback from the motors and sensors. The experiments on NAO and RoboErectus teen-size humanoid robots show that the proposed vision system is robust and accurate under different lighting conditions and can effectively and precisely locate robots and other objects.

  1. Synaesthetic Colours Can Behave More like Recalled Colours, as Opposed to Physical Colours that Can Be Seen

    Directory of Open Access Journals (Sweden)

    Derek H. Arnold

    2011-05-01

    Full Text Available Grapheme-color synaesthesia is an atypical condition characterized by coloured sensations when reading achromatic text. Different forms have been characterized, but this is somewhat controversial. In associative grapheme-colour synaesthesia, written graphemes can automatically trigger a sensation of colour in the ‘mind's eye’, but hearing the name of a grapheme does not. This allowed us explore the precision with which synaesthetes match triggered synaesthetic colours across separate presentations, versus the precision for recalled experiences cued by spoken graphemes. We recorded CIE coordinates, and found that matches for triggered sensations were equally variable relative to recalled experiences. To ensure this was not due to insensitivity of our apparatus, we next had synaesthetes and age-matched controls either match the colour of a circular patch while they could see it, or from memory after it had disappeared. Both synaesthetes and controls were more variable when matching from memory, and synaesthetes were more precise when matching colour hue, but not brightness. Interestingly, the variance of synaesthetes' recalled matches in this experiment matched that associated with synaesthetic colours in the first experiment. Overall, our data suggests that, for associative grapheme-colour synaesthetes, synaesthetic colours behave more like recalled colours, as opposed to physical colours that can be seen.

  2. Genotype-phenotype relationships in human red/green color-vision defects: Molecular and psychophysical studies

    Energy Technology Data Exchange (ETDEWEB)

    Deeb, S.S.; Motulsky, A.G.; Lindsey, D.T.; Hibiya, Y.; Sanocki, E.; Winderickx, J.; Teller, D.Y. (Univ. of Washington, Seattle, WA (United States))

    1992-10-01

    The relationship between the molecular structure of the X-linked red and green visual pigment genes and color-vision phenotype as ascertained by anomaloscopy was studied in 64 color-defective males. The great majority of red-green defects were associated with either the deletion of the green-pigment gene or the formation of 5[prime] red-green hybrid genes or 5[prime] green-red hybrid genes. A rapid PCR-based method allowed detection of hybrid genes, including those undetectable by Southern blot analysis, as well as more precise localization of the fusion points in hybrid genes. Protan color-vision defects appeared always associated with 5[prime] red-green hybrid genes. Carriers of single red-green hybrid genes with fusion in introns 1-4 were protanopes. However, carriers of hybrid genes with red-green fusions in introns 2, 3, or 4 in the presence of additional normal green genes manifested as either protanopes or protanomalous trichromats, with the majority being protanomalous. Deutan defects were associated with green-pigment gene deletions, with 5[prime] green-red hybrid genes, or, rarely, with 5[prime] green-red-green hybrid genes. Complete green-pigment gene deletions or green-red fusions in intron 1 were usually associated with deuteranopia, although the authors unexpectedly found three carriers of a single red-pigment gene without any green-pigment genes to be deuteranomalous trichromats. All but one of the other deuteranomalous subjects had green-red hybrid genes with intron 1, 2, 3, or 4 fusions, as well as several normal green-pigment genes. The one exception had a grossly normal gene array, presumably with a more subtle mutation. Amino acid differences in exon 5 largely determine whether a hybrid gene will be more redlike or more greenlike in phenotype. Various discrepancies as to severity (dichromacy or trichromacy) remain unexplained but may arise because of variability of expression, postreceptoral variation, or both.

  3. Multicolour interphase cytogenetics: 24 chromosome probes, 6 colours, 4 layers.

    Science.gov (United States)

    Ioannou, D; Meershoek, E J; Thornhill, A R; Ellis, M; Griffin, D K

    2011-01-01

    From the late 1980s onwards, the use of DNA probes to visualise sequences on individual chromosomes (fluorescent in-situ hybridisation - FISH) revolutionised the study of cytogenetics. Following single colour experiments, more fluorochromes were added, culminating in a 24 colour assay that could distinguish all human chromosomes. Interphase cytogenetics (the detection of chromosome copy number in interphase nuclei) soon followed, however 24 colour experiments are hampered for this application as mixing fluorochromes to produce secondary colours produces images that are not easily distinguishable from overlapping signals. This study reports the development and use of a novel protocol, new fast hybridising FISH probes, and a bespoke image capture system for the assessment of chromosome copy number in interphase nuclei. The multicolour probe sets can be used individually or in sequential hybridisation layers to assess ploidy of all 24 human chromosomes in the same nucleus. Applications of this technique are in the investigation of chromosome copy number and the assessment of nuclear organisation for a range of different cell types including human sperm, cancer cells and preimplantation embryos.

  4. The colour of architecture. Past and present

    Directory of Open Access Journals (Sweden)

    Veronica Maria Zybaczynski

    2013-12-01

    Full Text Available Colour has accompanied man throughout time since the beginnings, the primitive man used colour to paint drawings in caves, so the relationship between man and colour was, and still is, one of the closest. In architecture, colour swung between the magic, ritualic role and aesthetics, between outside and inside, scoring or reinterpreting in every step new facets and meanings. This article is a brief overview of the main aspects of this evolution, from the prehistoric times to the present with an emphasis on the relationship between the colour and the architectural composition.

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

    Science.gov (United States)

    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.

  6. Near Vision Test for Adults

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  7. Colour dependence of zodiacal light models

    Science.gov (United States)

    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.

  8. -Colour Self-Inverse Compositions

    Indian Academy of Sciences (India)

    Geetika Narang; A K Agarwal

    2006-08-01

    MacMahon’s definition of self-inverse composition is extended to -colour self-inverse composition. This introduces four new sequences which satisfy the same recurrence relation with different initial conditions like the famous Fibonacci and Lucas sequences. For these new sequences explicit formulas, recurrence relations, generating functions and a summation formula are obtained. Two new binomial identities with combinatorial meaning are also given.

  9. Colour Reconnection - Models and Tests

    CERN Document Server

    Christiansen, Jesper R

    2015-01-01

    Recent progress on colour reconnection within the Pythia framework is presented. A new model is introduced, based on the SU(3) structure of QCD and a minimization of the potential string energy. The inclusion of the epsilon structure of SU(3) gives a new baryon production mechanism and makes it possible simultaneously to describe hyperon production at both $e^+e^-$ and pp colliders. Finally, predictions for $e^+e^-$ colliders, both past and potential future ones, are presented.

  10. Structural colouration of mammalian skin: convergent evolution of coherently scattering dermal collagen arrays.

    Science.gov (United States)

    Prum, Richard O; Torres, Rodolfo H

    2004-05-01

    For more than a century, the blue structural colours of mammalian skin have been hypothesized to be produced by incoherent, Rayleigh or Tyndall scattering. We investigated the colour, anatomy, nanostructure and biophysics of structurally coloured skin from two species of primates - mandrill (Mandrillus sphinx) and vervet monkey (Cercopithecus aethiops) - and two species of marsupials - mouse opossum (Marmosa mexicana) and wooly opossum (Caluromys derbianus). We used two-dimensional (2-D) Fourier analysis of transmission electron micrographs (TEMs) of the collagen arrays in the primate tissues to test whether these structural colours are produced by incoherent or coherent scattering (i.e. constructive interference). The structural colours in Mandrillus rump and facial skin and Cercopithecus scrotum are produced by coherent scattering by quasi-ordered arrays of parallel dermal collagen fibres. The 2-D Fourier power spectra of the collagen arrays from Mandrillus and Cercopithecus reveal ring-shaped distributions of Fourier power at intermediate spatial frequencies, demonstrating a substantial nanostructure of the appropriate spatial frequency to produce the observed blue hues by coherent scattering alone. The Fourier power spectra and the observed reflectance spectra falsify assumptions and predictions of the incoherent, Rayleigh scattering hypothesis. Samples of blue Marmosa and Caluromys scrotum conform generally to the anatomy seen in Mandrillus and Cercopithecus but were not sufficiently well preserved to conduct numerical analyses. Colour-producing collagen arrays in mammals have evolved multiple times independently within the two clades of mammals known to have trichromatic colour vision. Mammalian colour-producing collagen arrays are anatomically and mechanistically identical to structures that have evolved convergently in the dermis of many lineages of birds, the tapetum of some mammals and the cornea of some fishes. These collagen arrays constitute quasi

  11. Genetics Home Reference: color vision deficiency

    Science.gov (United States)

    ... SERIES TRITANOPIA Sources for This Page Deeb SS. Molecular genetics of color-vision deficiencies. Vis Neurosci. 2004 May-Jun;21(3):191-6. Review. Citation on PubMed Deeb SS. The molecular basis of variation in human color vision. Clin Genet. 2005 May;67(5): ...

  12. Holi colours contain PM10 and can induce pro-inflammatory responses.

    Science.gov (United States)

    Bossmann, Katrin; Bach, Sabine; Höflich, Conny; Valtanen, Kerttu; Heinze, Rita; Neumann, Anett; Straff, Wolfgang; Süring, Katrin

    2016-01-01

    At Holi festivals, originally celebrated in India but more recently all over the world, people throw coloured powder (Holi powder, Holi colour, Gulal powder) at each other. Adverse health effects, i.e. skin and ocular irritations as well as respiratory problems may be the consequences. The aim of this study was to uncover some of the underlying mechanisms. We analysed four different Holi colours regarding particle size using an Electric field cell counting system. In addition, we incubated native human cells with different Holi colours and determined their potential to induce a pro-inflammatory response by quantifying the resulting cytokine production by means of ELISA (Enzyme Linked Immunosorbent Assay) and the resulting leukocyte oxidative burst by flow cytometric analysis. Moreover, we performed the XTT (2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and Propidium iodide cytotoxicity tests and we measured the endotoxin content of the Holi colour samples by means of the Limulus Amebocyte Lysate test (LAL test). We show here that all tested Holi colours consist to more than 40 % of particles with an aerodynamic diameter smaller than 10 μm, so called PM10 particles (PM, particulate matter). Two of the analysed Holi powders contained even more than 75 % of PM10 particles. Furthermore we demonstrate in cell culture experiments that Holi colours can induce the production of the pro-inflammatory cytokines TNF-α (Tumor necrosis factor-α), IL-6 (Interleukine-6) and IL-1β (Interleukine-1β). Three out of the four analysed colours induced a significantly higher cytokine response in human PBMCs (Peripheral Blood Mononuclear Cells) and whole blood than corn starch, which is often used as carrier substance for Holi colours. Moreover we show that corn starch and two Holi colours contain endotoxin and that certain Holi colours display concentration dependent cytotoxic effects in higher concentration. Furthermore we reveal that in principle Holi

  13. Single-colour flow cytometric assay to determine NK cell-mediated cytotoxicity and viability against non-adherent human tumor cells.

    Science.gov (United States)

    Thakur, Ajit; Zaman, Abeyat; Hummel, Jeff; Jones, Kim; Hortelano, Gonzalo

    2012-03-01

    A flow cytometry-based cytotoxicity (FCC) assay was developed using a single fluorophore, calcein-acetoxymethyl diacetylester (calcein-AM), to measure NK cell-mediated cytotoxicity. Non-adherent human K562 and U937 target cells were individually labelled with calcein-AM and co-incubated with effector NK cells to measure calcein loss, and therefore calculate target cell cytotoxicity. This FCC assay also provided a measure of sample viability. Notably, cell viability measured by traditional calcein/7-amino-actinomycin D (7-AAD) double labelling and Trypan Blue methods were comparable to the viability calculated using calcein-loss FCC. This FCC assay may also be used with various effector and target cell types and as a multi-parameter tool to measure viability and immunophenotype cells for tissue engineering purposes.

  14. Colours sometimes count: awareness and bidirectionality in grapheme-colour synaesthesia.

    Science.gov (United States)

    Johnson, Addie; Jepma, Marieke; de Jong, Ritske

    2007-10-01

    Three experiments were conducted with 10 grapheme-colour synaesthetes and 10 matched controls to investigate (a) whether awareness of the inducer grapheme is necessary for synaesthetic colour induction and (b) whether grapheme-colour synaesthesia may be bidirectional in the sense that not only do graphemes induce colours, but that colours influence the processing of graphemes. Using attentional blink and Stroop paradigms with digit targets, we found that some synaesthetes did report "seeing" synaesthetic colours even when they were not able to report the inducing digit. Moreover, congruency effects (effects of matching the colour of digit presentation with the synaesthetic colour associated with that digit) suggested that grapheme-colour synaesthesia can be bidirectional, at least for some synaesthetes.

  15. Color in machine vision and its application

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Color is the phenomenon of human visual perception and the module of machine vision. Color information is widely used in the areas of virtual reality and humancomputer interaction. Color is the product of a visual environment, illumination and the human brain. Research on color information representation and its processing is typically interdisciplinary. Based on our research work on human color perception and machine color vision and its application, we summarized the hotspots of color studies in recent developments and new approaches to color vision,including basic theories and the application of color information in virtual reality, content-based image retrieval, and face recognition.

  16. Measurement and prediction of pork colour.

    Science.gov (United States)

    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.

  17. PUNGENT AND COLOUR COMPOUNDS OF RED PEPPERS

    Directory of Open Access Journals (Sweden)

    Çetin KADAKAL

    2001-03-01

    Full Text Available The capcaicinoid amount of red peppers from Solanacea family is used for the evaluation of quality and classification in many countries. Capsaicin is the major pungent principle (69 % of capsaicinoids. The others are dihidrocapsaicin (22 %, nordihidrocapsaicin (7 %, homocapsaicin (1 % and homodihidrocapsaicin (1 %. As in most foods, the carotenoids of red peppers are also important compounds. Carotenoids are typical colour pigments and some of them have vitamin A activity. Major carotenoids of ripe fruit of red peppers are capsanthin, capsorubin, ß-carotene and zeaxanthin. Capcaicinoid and carotenoid contents of red peppers grown in many different regions of the world, their properties and roles on the human health were given in this review.

  18. DOES WORKING IN A COAL MINE INFLUENCE EYE AND VISION FUNCTIONS

    Directory of Open Access Journals (Sweden)

    Uroš Prelesnik

    2002-12-01

    Full Text Available Background. In the article we described the condition of miners vision before they started working in the mine and after twenty years of continuous work in the pit. We presumed that working in the dark and uncomfortable conditions distort the vision. We found no similar analysis in the literature that was available to us. So we started with the analysis in our institution. As ophthalmologist and specialist of occupational medicine we daily came across miners questions and findings about the distortion of their vision after working in the pit for many years. Criteria of visual functions for the miners are: visual acuity of the better eye should be at least 0.7 and at least 0.5 of the worse one, without correction. He has to have normal binocular vision and normal night vision. Normal colour vision is not obligatory for the miners which allows the dicromats (colour blind people to work, too.Methods. We treated 50 miners who started to work in the mine in the years 1977–1979 and have spent their whole working period in the mine. We had a lot of problems choosing the miners because of fluctuation (superannuations, leaving Slovenia, so they did not come to ophthalmologist at the end of their working period. In our dispensary of occupational medicine they were last treated the last year before retiring, while the ophthalmologist examined them in the years 1997–1999. In our dispensary of occupational medicine they were examined by the orthoreter or R 22 where monocular vision, binocular vision, depth vision and colour vision were checked.The ophthalmologist examined the vision without and with correction, measured the eye pressure, performed the examination on the slitlamp and checked the eye background.Results. The check-ups in dispensary of occupational with examinations of vision, phoria, depth vision and colour vision showed no statistically important differences. But when we checked the patients in the ophthalmologic ambulance we found out

  19. Design and Evaluation of a Thermal Tactile Display for Colour Rendering

    Directory of Open Access Journals (Sweden)

    Zhen Jia

    2015-11-01

    Full Text Available This paper proposes a novel method of manipulating both thermal change rate and thermal intensity to convey colour information by using a thermal tactile display. The colour-space transformation from {red, green, blue} to {hue, saturation, intensity} is introduced, and the mapping between colour and temperature is established based on warm and cold colours. Considering the lower resolution of the tactile channel, six limited stimulation levels are generated to represent colours. Based on the semi-infinite body model, the thermal response within the skin for each stimulation form is investigated. The Peltier element of the display is designed to convey different thermal stimuli to the human finger. Two experiments are performed to evaluate the performance of the display: colour identification and discrimination. Experimental results indicate that there is a response bias among the perceived colours for the traditional method of only employing thermal intensity, but there is no response bias for the proposed method; subjects’ mean recognition accuracy with the proposed method is significantly higher than that gained using the traditional method. Furthermore, colour information of the captured images can be reliably discriminated by using this devised thermal tactile display.

  20. True and false memory for colour names versus actual colours: support for the visual distinctiveness heuristic in memory for colour information.

    Science.gov (United States)

    Eslick, Andrea N; Kostic, Bogdan; Cleary, Anne M

    2010-06-01

    In a colour variation of the Deese-Roediger-McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., "blood, cherry, scarlet, rouge ... "); they later showed false memory for the critical colour name (e.g., "red"). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.

  1. Rethinking Robot Vision - Combining Shape and Appearance

    Directory of Open Access Journals (Sweden)

    Matthias J. Schlemmer

    2008-11-01

    Full Text Available Equipping autonomous robots with vision sensors provides a multitude of advantages by simultaneously bringing up difficulties with regard to different illumination conditions. Furthermore, especially with service robots, the objects to be handled must somehow be learned for a later manipulation. In this paper we summarise work on combining two different vision sensors, namely a laser range scanner and a monocular colour camera, for shape-capturing, detecting and tracking of objects in cluttered scenes without the need of intermediate user interaction. The use of different sensor types provides the advantage of separating the shape and the appearance of the object and therefore overcome the problem with changing illumination conditions. We describe the framework and its components of visual shape-capturing, fast 3D object detection and robust tracking as well as examples that show the feasibility of this approach.

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

    Science.gov (United States)

    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.

  3. Molecular tests for coat colours in horses.

    Science.gov (United States)

    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.

  4. Social perception in synaesthesia for colour.

    Science.gov (United States)

    Janik McErlean, Agnieszka B; Susilo, Tirta; Rezlescu, Constantin; Bray, Amy; Banissy, Michael J

    Synaesthesia is a rare phenomenon in which stimulation in one modality (e.g., audition) evokes a secondary percept not associated with the first (e.g., colour). Prior work has suggested links between synaesthesia and other neurodevelopmental conditions that are linked to altered social perception abilities. With this in mind, here we sought to examine social perception abilities in grapheme-colour synaesthesia (where achromatic graphemes evoke colour experiences) by examining facial identity and facial emotion perception in synaesthetes and controls. Our results indicate that individuals who experience grapheme-colour synaesthesia outperformed controls on tasks involving fine visual discrimination of facial identity and emotion, but not on tasks involving holistic face processing. These findings are discussed in the context of broader perceptual and cognitive traits previously associated with synaesthesia for colour, with the suggestion that performance benefits shown by grapheme-colour synaesthetes may be related to domain-general visual discrimination biases observed in this group.

  5. Developments in medical image processing and computational vision

    CERN Document Server

    Jorge, Renato

    2015-01-01

    This book presents novel and advanced topics in Medical Image Processing and Computational Vision in order to solidify knowledge in the related fields and define their key stakeholders. It contains extended versions of selected papers presented in VipIMAGE 2013 – IV International ECCOMAS Thematic Conference on Computational Vision and Medical Image, which took place in Funchal, Madeira, Portugal, 14-16 October 2013.  The twenty-two chapters were written by invited experts of international recognition and address important issues in medical image processing and computational vision, including: 3D vision, 3D visualization, colour quantisation, continuum mechanics, data fusion, data mining, face recognition, GPU parallelisation, image acquisition and reconstruction, image and video analysis, image clustering, image registration, image restoring, image segmentation, machine learning, modelling and simulation, object detection, object recognition, object tracking, optical flow, pattern recognition, pose estimat...

  6. Colour-independent partition functions in coloured vertex models

    CERN Document Server

    Foda, O

    2013-01-01

    We study lattice configurations related to S_n, the scalar product of an off-shell state and an on-shell state in rational A_n integrable vertex models, n = {1, 2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A_n models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S_2 [1, 2]. Namely, 1. S_2 which depends on two sets of Bethe roots, b_1 and b_2, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit b_1 -> infinity, and/or b_2 -> infinity, into a product of determinants, 2. Each of the la...

  7. Colour-independent partition functions in coloured vertex models

    Energy Technology Data Exchange (ETDEWEB)

    Foda, O., E-mail: omar.foda@unimelb.edu.au [Dept. of Mathematics and Statistics, University of Melbourne, Parkville, VIC 3010 (Australia); Wheeler, M., E-mail: mwheeler@lpthe.jussieu.fr [Laboratoire de Physique Théorique et Hautes Energies, CNRS UMR 7589 (France); Université Pierre et Marie Curie – Paris 6, 4 place Jussieu, 75252 Paris cedex 05 (France)

    2013-06-11

    We study lattice configurations related to S{sub n}, the scalar product of an off-shell state and an on-shell state in rational A{sub n} integrable vertex models, n∈{1,2}. The lattice lines are colourless and oriented. The state variables are n conserved colours that flow along the line orientations, but do not necessarily cover every bond in the lattice. Choosing boundary conditions such that the positions where the colours flow into the lattice are fixed, and where they flow out are summed over, we show that the partition functions of these configurations, with these boundary conditions, are n-independent. Our results extend to trigonometric A{sub n} models, and to all n. This n-independence explains, in vertex-model terms, results from recent studies of S{sub 2} (Caetano and Vieira, 2012, [1], Wheeler, (arXiv:1204.2089), [2]). Namely, 1.S{sub 2}, which depends on two sets of Bethe roots, {b_1} and {b_2}, and cannot (as far as we know) be expressed in single determinant form, degenerates in the limit {b_1}→∞, and/or {b_2}→∞, into a product of determinants, 2. Each of the latter determinants is an A{sub 1} vertex-model partition function.

  8. La Rousse and the Tapestry Artist: Tracy Chevalier’s Liberation through Images and Colours

    Directory of Open Access Journals (Sweden)

    Roxanne Barbara Doerr

    2012-12-01

    Full Text Available Art has always held a very ambiguous position in human society: on the one hand it has been exploited for promotional use and revered as a stand in for the entity it represents; on the other hand however, its ability to question dogmatic authorities by appealing to an individual’s innermost instincts and thoughts has made it a threatening and seditious force to be reckoned with. As a result, numerous studies on the impact of art and visions on society, authority, and our perception of reality, have emerged and taken many forms of interdisciplinary inquiry (it is sufficient to think of movements such as “literature and the visual arts”, “culture studies”, “cross-cultural image studies” or “law and imagery”, to mention a few. As a confirmation of this, the subversive power of art, in the form of suppressed colours and controversial portraits, is at the heart of two of Tracy Chevalier’s works, The Virgin Blue (1997 and The Lady and the Unicorn (2003. In both novels the protagonists’ lives are dominated by a strong patriarchal society that suppresses the voices of those who do not pertain to politically privileged categories. Art therefore is the force that leads the characters to leave the paths that had been assigned to them by custom and seek out their own future.

  9. Wood colour related to kiln drying

    OpenAIRE

    Sundqvist, Bror

    2000-01-01

    Raised temperature in artificial drying has led to some changes of wood products such as colour and strength etc. For special treatment of wood-products with clearly modified properties, among them colour, is often high temperature and steam used industrially. Knowledge about the colour rendering from wood that is subjected to heat under humid conditions and/or artificial drying, especially kiln drying, is thus of interest. It is also of interest to understand the chemical background, for the...

  10. Identification of Colour Reconnection using Factorial Correlator

    Institute of Scientific and Technical Information of China (English)

    FU Jing-Hua; LIU Lian-Shou

    2000-01-01

    A new signal is proposed for the colour reconnection in the hadronic decay of W+ W- in e+e- collisions. Using Pythia Monte Carlo it is shown that factorial correlators for W+ and W- without colour reconnection are almost identical to unity, while those for the cases with colour reconnection fall down approximately linearly in the log log plot. This signal, being based on the factorial correlator, is more sensitive than the ones using only averaged quantities.

  11. Colour in visualisation for computational fluid dynamics

    OpenAIRE

    2006-01-01

    Colour is used in computational fluid dynamic (CFD) simulations in two key ways. First it is used to visualise the geometry and allow the engineers to be confident that the model constructed is a good representation of the engineering situation. Once an analysis has been completed, colour is used in post-processing the data from the simulations to illustrate the complex fluid mechanic phenomena under investigation. This paper describes these two uses of colour and provides some examples to il...

  12. Gaze Duration Biases for Colours in Combination with Dissonant and Consonant Sounds: A Comparative Eye-Tracking Study with Orangutans

    Science.gov (United States)

    Mühlenbeck, Cordelia; Liebal, Katja; Pritsch, Carla; Jacobsen, Thomas

    2015-01-01

    Research on colour preferences in humans and non-human primates suggests similar patterns of biases for and avoidance of specific colours, indicating that these colours are connected to a psychological reaction. Similarly, in the acoustic domain, approach reactions to consonant sounds (considered as positive) and avoidance reactions to dissonant sounds (considered as negative) have been found in human adults and children, and it has been demonstrated that non-human primates are able to discriminate between consonant and dissonant sounds. Yet it remains unclear whether the visual and acoustic approach–avoidance patterns remain consistent when both types of stimuli are combined, how they relate to and influence each other, and whether these are similar for humans and other primates. Therefore, to investigate whether gaze duration biases for colours are similar across primates and whether reactions to consonant and dissonant sounds cumulate with reactions to specific colours, we conducted an eye-tracking study in which we compared humans with one species of great apes, the orangutans. We presented four different colours either in isolation or in combination with consonant and dissonant sounds. We hypothesised that the viewing time for specific colours should be influenced by dissonant sounds and that previously existing avoidance behaviours with regard to colours should be intensified, reflecting their association with negative acoustic information. The results showed that the humans had constant gaze durations which were independent of the auditory stimulus, with a clear avoidance of yellow. In contrast, the orangutans did not show any clear gaze duration bias or avoidance of colours, and they were also not influenced by the auditory stimuli. In conclusion, our findings only partially support the previously identified pattern of biases for and avoidance of specific colours in humans and do not confirm such a pattern for orangutans. PMID:26466351

  13. Hadronisation Models and Colour Reconnection

    CERN Document Server

    Bierlich, Christian

    2016-01-01

    Enhanced production of hadrons with $s$-quark content has been observed in $pp$ collisions at LHC, and earlier in collisions of heavy nuclei. We review the string hadronisation formalism and correc- tions from rope hadronisation and colour reconnection, corrections that takes place in such dense environments, and are able to correctly describe data. Since such corrections are very sensitive to the modelling of transverse proton structure, we investigate two such models, and compare to final states. Finally we describe how such corrections can also give a possible explanation to collective phenomena observed in small systems.

  14. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2011-01-01

    White Cast Iron (Ⅰ) White cast iron or ‘white iron' refers to the type of cast iron in which all of the carbon exists as carbide;there is no graphite in the as-cast structure and the fractured surface shows a white colour.White cast iron can be divided in three classes:· Normal white cast iron — this iron contains only C,Si,Mn,P and S,with no other alloying elements.· Low-alloy white cast iron — the total mass fraction of alloying elements is less than 5%.

  15. Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity

    Science.gov (United States)

    Pérez i de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

    2016-10-01

    Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis.

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

    Science.gov (United States)

    Théry, Marc; Casas, Jérôme

    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.

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

    Science.gov (United States)

    Théry, Marc; Casas, Jérôme

    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

  18. Behavioral Risk Factors - Vision & Eye Health

    Data.gov (United States)

    U.S. Department of Health & Human Services — 2005-2014. In 2013 and subsequently, one question in the core of BRFSS asks about vision: Are you blind or do you have serious difficulty seeing, even when wearing...

  19. Behavioral Risk Factors - Vision & Eye Health

    Data.gov (United States)

    U.S. Department of Health & Human Services — 2005-2015. In 2013 and subsequently, one question in the core of BRFSS asks about vision: Are you blind or do you have serious difficulty seeing, even when wearing...

  20. Correlation Analysis of Groundwater Colouration from Mountainous Areas, Ghana

    Directory of Open Access Journals (Sweden)

    R. Amfo-Otu

    2014-03-01

    Full Text Available Access to potable water is important for human development but inhabitants of mountainous areas face challenges of water supply due to inadequacy of the available surface water. Groundwater thus becomes the other alternative. The research was done on the groundwater quality with respect to colouration in five boreholes in some second cycle schools located in mountainous areas of the Akuapim North district. Four samples each were taken from the five boreholes for laboratory analysis. Colour, iron, manganese and some physical parameters were analysed and the results were compared with the World Health Organisation guidelines and the Ghana Urban Water Limited standard for drinking water. The results showed that conductivity and turbidity were all within the acceptable standards for drinking water. Colour strongly correlated positively with iron (r = 0.869, turbidity (r = 0.858, conductivity (r = 0.727 and manganese (r = 0.681, but pH (r = -0.715 strongly correlated negatively. Even though iron and manganese have no known health effects, they were associated with the colouration of the groundwater causing aesthetic problems for the users of the boreholes. Construction of a simple filter bed with aeration facility is critical to remove iron and manganese from the water to make it potable to the consumers. DOI: http://dx.doi.org/10.5755/j01.erem.67.1.4545

  1. Shell Colour Polymorphism in Bulla ampulla

    DEFF Research Database (Denmark)

    Cedhagen, Tomas

    1999-01-01

    Colour patterns of Bulla ampulla shells collected from Africa eastward to Pacific Islands were studied. 1\\vo common colour morphs were found. The typical morph is commonest. It is closely and finely mottled or all over with pinkish-gray on a creamy or flesh~tinted ground, with darker clouds......, irregular, V-shaped, or as longitudinal bands. The colouration of the other common morph is more uniform. It is lacking the darker clouds or bands and the colour is more greyish. The entire shell surface is densely mottled all over with small brown spots on a grey or beige background. Both morphs seem...

  2. Assessing the colour quality of LED sources

    DEFF Research Database (Denmark)

    Jost-Boissard, S.; Avouac, P.; Fontoynont, Marc

    2015-01-01

    sources and especially some LEDs. In this paper, several aspects of perceived colour quality are investigated using a side-by-side paired comparison method, and the following criteria: naturalness of fruits and vegetables, colourfulness of the Macbeth Color Checker chart, visual appreciation...... by the CIECAM02 Uniform Colour Space. Naturalness is better described by fidelity indices even if they did not give perfect predictions for all differences between LED light sources. Colourfulness is well described by gamut-based indices and attractiveness was found to correlate best with gamut-based indices...

  3. Clique colouring of binomial random graphs

    OpenAIRE

    Mcdiarmid, Colin; Mitsche, Dieter; Pralat, Pawel

    2016-01-01

    A clique colouring of a graph is a colouring of the vertices so that no maximal clique is monochromatic (ignoring isolated vertices). The smallest number of colours in such a colouring is the clique chromatic number. In this paper, we study the asymptotic behaviour of the clique chromatic number of the random graph G(n,p) for a wide range of edge-probabilities p=p(n). We see that the typical clique chromatic number, as a function of the average degree, forms an intriguing step function.

  4. Automated digital mapping of geological colour descriptions

    Science.gov (United States)

    Jenkins, Chris

    2002-12-01

    Sediment colour data are delivered by geologists as Munsell codes (Rock Color Chart) and linguistic descriptions. Using new software suitable for very large data sets, the two types can be brought into conformance and mapped together digitally. The native codes are extracted. For linguistic descriptions chromatic terms are identified with Munsell codes, then mixed in a temporary transform of psychometrically linear CIE colour space. Adjustments are made for dark/light and pale/strong modifiers. The output Munsell codes are statistically validated and mapped using special GIS legends to render them in true colour. The output displays provide a new view of marine sediment facies, comparable to remotely sensed colour imagery.

  5. Usability of Calibrating Monitor for Soft Proof According to CIE CAM02 Colour Appearance Model

    Directory of Open Access Journals (Sweden)

    Dragoljub Novakovic

    2010-06-01

    Full Text Available Colour appearance models describe viewing conditions and enable simulating appearance of colours under different illuminants and illumination levels according to human perception. Since it is possible to predict how colour would look like when different illuminants are used, colour appearance models are incorporated in some monitor profiling software. Owing to these software, tone reproduction curve can be defined by taking into consideration viewing condition in which display is observed. In this work assessment of CIE CAM02 colour appearance model usage at calibrating LCD monitor for soft proof was tested in order to determine which tone reproduction curve enables better reproduction of colour. Luminance level was kept constant, whereas tone reproduction curves determined by gamma values and by parameters of CIE CAM02 model were varied. Testing was conducted in case where physical print reference is observed under illuminant which has colour temperature according to iso standard for soft-proofing (D50 and also for illuminants D65.  Based on the results of calibrations assessment, subjective and objective assessment of created profiles, as well as on the perceptual test carried out on human observers, differences in image display were defined and conclusions of the adequacy of CAM02 usage at monitor calibration for each of the viewing conditions reached.

  6. Usability of Calibrating Monitor for Soft Proof According to cie cam02 Colour Appearance Model

    Directory of Open Access Journals (Sweden)

    Ivana Tomić

    2010-01-01

    Full Text Available Colour appearance models describe viewing conditions and enable simulating appearance of colours under different illuminants and illumination levels according to human perception. Since it is possible to predict how colour would look like when different illuminants are used, colour appearance models are incorporated in some monitor profiling software. Owing to these software, tone reproduction curve can be defined by taking into consideration viewing condition in which display is observed. In this work assessment of cie cam02 colour appearance model usage at calibrating lcd monitor for soft proof was tested in order to determine which tone reproduction curve enables better reproduction of colour. Luminance level was kept constant, whereas tone reproduction curves determined by gamma values and by parameters of cie cam02 model were varied. Testing was conducted in case where physical print reference is observed under illuminant which has colour temperature according to iso standard for soft-proofing (d50 and also for illuminants d65. Based on the results of calibrations assessment, subjective and objective assessment of created profiles, as well as on the perceptual test carried out on human observers, differences in image display were defined and conclusions of the adequacy of cam02 usage at monitor calibration for each of the viewing conditions reached.

  7. Ames vision group research overview

    Science.gov (United States)

    Watson, Andrew B.

    1990-01-01

    A major goal of the reseach group is to develop mathematical and computational models of early human vision. These models are valuable in the prediction of human performance, in the design of visual coding schemes and displays, and in robotic vision. To date researchers have models of retinal sampling, spatial processing in visual cortex, contrast sensitivity, and motion processing. Based on their models of early human vision, researchers developed several schemes for efficient coding and compression of monochrome and color images. These are pyramid schemes that decompose the image into features that vary in location, size, orientation, and phase. To determine the perceptual fidelity of these codes, researchers developed novel human testing methods that have received considerable attention in the research community. Researchers constructed models of human visual motion processing based on physiological and psychophysical data, and have tested these models through simulation and human experiments. They also explored the application of these biological algorithms to applications in automated guidance of rotorcraft and autonomous landing of spacecraft. Researchers developed networks for inhomogeneous image sampling, for pyramid coding of images, for automatic geometrical correction of disordered samples, and for removal of motion artifacts from unstable cameras.

  8. Assessing the binocular advantage in aided vision.

    Science.gov (United States)

    Harrington, Lawrence K; McIntire, John P; Hopper, Darrel G

    2014-09-01

    Advances in microsensors, microprocessors, and microdisplays are creating new opportunities for improving vision in degraded environments through the use of head-mounted displays. Initially, the cutting-edge technology used in these new displays will be expensive. Inevitably, the cost of providing the additional sensor and processing required to support binocularity brings the value of binocularity into question. Several assessments comparing binocular, binocular, and monocular head-mounted displays for aided vision have concluded that the additional performance, if any, provided by binocular head-mounted displays does not justify the cost. The selection of a biocular [corrected] display for use in the F-35 is a current example of this recurring decision process. It is possible that the human binocularity advantage does not carry over to the aided vision application, but more likely the experimental approaches used in the past have been too coarse to measure its subtle but important benefits. Evaluating the value of binocularity in aided vision applications requires an understanding of the characteristics of both human vision and head-mounted displays. With this understanding, the value of binocularity in aided vision can be estimated and experimental evidence can be collected to confirm or reject the presumed binocular advantage, enabling improved decisions in aided vision system design. This paper describes four computational approaches-geometry of stereopsis, modulation transfer function area for stereopsis, probability summation, and binocular summation-that may be useful in quantifying the advantage of binocularity in aided vision.

  9. Colours sometimes count : Awareness and bidirectionality in grapheme-colour synaesthesia

    NARCIS (Netherlands)

    Johnson, Addie; Jepma, Marieke; de Jong, Ritske

    2007-01-01

    Three experiments were conducted with 10 grapheme-colour synaesthetes and 10 matched controls to investigate (a) whether awareness of the inducer grapheme is necessary for synaesthetic colour induction and (b) whether grapheme-colour synaesthesia may be bidirectional in the sense that not only do gr

  10. Colours sometimes count : Awareness and bidirectionality in grapheme-colour synaesthesia

    NARCIS (Netherlands)

    Johnson, Addie; Jepma, Marieke; de Jong, Ritske

    2007-01-01

    Three experiments were conducted with 10 grapheme-colour synaesthetes and 10 matched controls to investigate (a) whether awareness of the inducer grapheme is necessary for synaesthetic colour induction and (b) whether grapheme-colour synaesthesia may be bidirectional in the sense that not only do gr

  11. Disruptive visions.

    Science.gov (United States)

    Satava, R M

    2002-10-01

    Numerous advanced technologies, both medical and nonmedical, are emerging faster than their social, behavioral, political, moral, and ethical implications can be understood. Some of these technologies will fundamentally challenge the practice of surgery: human cloning, genetic engineering, tissue engineering, intelligent robotics, nanotechnology, suspended animation, regeneration, and species prolongation. Because of the rapidity of change, the current status of these emerging technologies with their specific moral and ethical issues must be addressed at this time by the new generation of surgeons, or we must all face the consequences of an uncontrolled and unprepared future.

  12. Chemicals Industry Vision

    Energy Technology Data Exchange (ETDEWEB)

    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).

  13. Home vision tests

    Science.gov (United States)

    ... the distance vision test above, but it is held only 14 inches (36 centimeters) away. If you ... Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the ...

  14. Electrophysiological measurement of the effect of inter-stimulus competition on early cortical stages of human vision.

    Science.gov (United States)

    Miller, Claire E; Shapiro, Kimron L; Luck, Steven J

    2015-01-15

    Competition between inputs in early visual cortex has been established as a key determinant in perception through decades of animal single cell and human fMRI research. We developed a novel ERP paradigm allowing this competition to be studied in humans, affording an opportunity to gain further insight into how competition is reflected at the neural level. Checkerboard stimuli were presented to elicit C1 (indexing processing in V1), C2 (hypothesized to reflect V1 after extrastriate feedback), and P1 (extrastriate) components. Stimuli were presented in three randomized conditions: single stimulus, near proximity pairs and far proximity pairs. Importantly, near stimuli (0.16° visual angle apart) were positioned to compete in primary visual cortex, whereas far stimuli (2° apart) were positioned to compete in extrastriate visual areas. As predicted, the degree and spatial range of competition increased from the C1 component to the C2 and P1 components. Specifically, competitive interactions in C1 amplitude were modest and present only for near-proximity pairs, whereas substantial competition was present for the P1, even for far-proximity pairs. To our knowledge, this is the first study to measure how competition unfolds over time in human visual cortex. Importantly, this method provides an empirical means of measuring competitive interactions at specific stages of visual processing, rendering it possible to rigorously test predictions about the effects of competition on perception, attention, and working memory.

  15. Coherent laser vision system

    Energy Technology Data Exchange (ETDEWEB)

    Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)

    1995-10-01

    The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

  16. Robot Vision Library

    Science.gov (United States)

    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

  17. Epiretinal transplantation of human bone marrow mesenchymal stem cells rescues retinal and vision function in a rat model of retinal degeneration.

    Science.gov (United States)

    Tzameret, Adi; Sher, Ifat; Belkin, Michael; Treves, Avraham J; Meir, Amilia; Nagler, Arnon; Levkovitch-Verbin, Hani; Rotenstreich, Ygal; Solomon, Arieh S

    2015-09-01

    Vision incapacitation and blindness associated with incurable retinal degeneration affect millions of people worldwide. In this study, 0.25×10(6) human bone marrow stem cells (hBM-MSCs) were transplanted epiretinally in the right eye of Royal College Surgeons (RCS) rats at the age of 28 days. Epiretinally transplanted cells were identified as a thin layer of cells along vitreous cavity, in close proximity to the retina or attached to the lens capsule, up to 6 weeks following transplantation. Epiretinal transplantation delayed photoreceptor degeneration and rescued retinal function up to 20 weeks following cell transplantation. Visual functions remained close to normal levels in epiretinal transplantation rats. No inflammation or any other adverse effects were observed in transplanted eyes. Our findings suggest that transplantation of hBM-MSCs as a thin epiretinal layer is effective for treatment of retinal degeneration in RCS rats, and that transplanting the cells in close proximity to the retina enhances hBM-MSC therapeutic effect compared with intravitreal injection.

  18. Particular application of methods of AdaBoost and LBP to the problems of computer vision

    OpenAIRE

    Волошин, Микола Володимирович

    2012-01-01

    The application of AdaBoost method and local binary pattern (LBP) method for different spheres of computer vision implementation, such as personality identification and computer iridology, is considered in the article. The goal of the research is to develop error-correcting methods and systems for implements of computer vision and computer iridology, in particular. This article considers the problem of colour spaces, which are used as a filter and as a pre-processing of images. Method of AdaB...

  19. Enhanced depth perception using hyperstereo vision

    Science.gov (United States)

    Watkins, Wendell R.

    1997-06-01

    Recent stereo vision experiments demonstrated the enhancement of depth perception over single line of sight vision for improved vehicular navigation and target acquisition processes. The experiments involves the use of stereo vision headsets connected to visible and 8 - 12 micrometers IR imagers. The imagers were separated by up to 50 m (i.e., wider platform separation than human vision, or hyperstereo) and equipped with telescopes for viewing at ranges of tens of meters up to 4 km. The important findings were: (1) human viewers were able to discern terrain undulations for obstacle avoidance for vehicular navigation, and (2) human viewers were able to detect depth features within the scenes that enhanced the target acquisition process over using monocular or single line of sight viewing. For vehicular navigation improvement, stereo goggles were developed for headset display and simultaneous see through instrumentation viewing for vehicular navigation enhancement. For detection, the depth cues can be used to detect even salient target features.

  20. Representing Object Colour in Language Comprehension

    Science.gov (United States)

    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…

  1. Quantum theory of colour discrimination of dichromats

    NARCIS (Netherlands)

    Bouman, M.A.; Walraven, P.L.

    1962-01-01

    The hypothesis of de Vries and Rose has been applied to colour discrimination of dichromates. The hypothesis states that a brightness difference ΔB is just beyond threshold, when ΔB just exceeds the statistical fluctuations in background brightness B, which are proportional to B 1 2. The colour diff

  2. Brilliant Colours from a White Snow Cover

    Science.gov (United States)

    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…

  3. Finite mutation classes of coloured quivers

    CERN Document Server

    Torkildsen, Hermund André

    2010-01-01

    We consider the general notion of coloured quiver mutation and show that the mutation class of a coloured quiver $Q$, arising from an $m$-cluster tilting object associated with $H$, is finite if and only if $H$ is of finite or tame representation type, or it has at most 2 simples. This generalizes a result known for 1-cluster categories.

  4. Colour measurement and white blood cell recognition

    CERN Document Server

    Gelsema, E S

    1972-01-01

    As a part of a collaboration with NEMCH aimed at the automation of the differential white blood cell count, studies have been made of the different possibilities for using colour to help in the recognition process. Results are presented comparing data obtained with a microspectrophotometer and with a simulated three-colour scanner.

  5. Instrumental colour classification of veal carcasses

    NARCIS (Netherlands)

    Hulsegge, B.; Engel, B.; Buist, W.; Merkus, G.S.M.; Klont, R.E.

    2001-01-01

    Three experiments, involving over 56 000 veal carcasses, were carried out to develop a method for instrumental colour classification of veal carcasses at 45 min post mortem with the Minolta CR300. The method should produce results similar to those of the 10-point colour-system, which is currently in

  6. Soft Computing Techniques in Vision Science

    CERN Document Server

    Yang, Yeon-Mo

    2012-01-01

    This Special Edited Volume is a unique approach towards Computational solution for the upcoming field of study called Vision Science. From a scientific firmament Optics, Ophthalmology, and Optical Science has surpassed an Odyssey of optimizing configurations of Optical systems, Surveillance Cameras and other Nano optical devices with the metaphor of Nano Science and Technology. Still these systems are falling short of its computational aspect to achieve the pinnacle of human vision system. In this edited volume much attention has been given to address the coupling issues Computational Science and Vision Studies.  It is a comprehensive collection of research works addressing various related areas of Vision Science like Visual Perception and Visual system, Cognitive Psychology, Neuroscience, Psychophysics and Ophthalmology, linguistic relativity, color vision etc. This issue carries some latest developments in the form of research articles and presentations. The volume is rich of contents with technical tools ...

  7. Improved colour matching technique for fused nighttime imagery with daytime colours

    Science.gov (United States)

    Hogervorst, Maarten A.; Toet, Alexander

    2016-10-01

    Previously, we presented a method for applying daytime colours to fused nighttime (e.g., intensified and LWIR) imagery (Toet and Hogervorst, Opt.Eng. 51(1), 2012). Our colour mapping not only imparts a natural daylight appearance to multiband nighttime images but also enhances the contrast and visibility of otherwise obscured details. As a result, this colourizing method leads to increased ease of interpretation, better discrimination and identification of materials, faster reaction times and ultimately improved situational awareness (Toet e.a., Opt.Eng.53(4), 2014). A crucial step in this colouring process is the choice of a suitable colour mapping scheme. When daytime colour images and multiband sensor images of the same scene are available the colour mapping can be derived from matching image samples (i.e., by relating colour values to sensor signal intensities). When no exact matching reference images are available the colour transformation can be derived from the first-order statistical properties of the reference image and the multiband sensor image (Toet, Info. Fus. 4(3), 2003). In the current study we investigated new colour fusion schemes that combine the advantages of the both methods, using the correspondence between multiband sensor values and daytime colours (1st method) in a smooth transformation (2nd method). We designed and evaluated three new fusion schemes that focus on: i) a closer match with the daytime luminances, ii) improved saliency of hot targets and iii) improved discriminability of materials

  8. Material and lighting dimensions of object colour.

    Science.gov (United States)

    Tokunaga, Rumi; Logvinenko, Alexander D

    2010-08-06

    The dimensionality of the object colour manifold was studied using a multidimensional scaling technique, which allows for the representation of a set of coloured papers as a configuration in a Euclidean space where the distance between papers corresponds to the perceptual dissimilarities between them. When the papers are evenly illuminated they can be arranged as a three-dimensional configuration. This is in line with the generally accepted view that the object colour space is three-dimensional. Yet, we show that under variegated illumination another three dimensions emerge. We call them lighting dimensions of object colour in order to distinguish from the traditional three referred to as material dimensions of object colour. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. A child's vision.

    Science.gov (United States)

    Nye, Christina

    2014-06-01

    Implementing standard vision screening techniques in the primary care practice is the most effective means to detect children with potential vision problems at an age when the vision loss may be treatable. A critical period of vision development occurs in the first few weeks of life; thus, it is imperative that serious problems are detected at this time. Although it is not possible to quantitate an infant's vision, evaluating ocular health appropriately can mean the difference between sight and blindness and, in the case of retinoblastoma, life or death.

  10. Computational approaches to vision

    Science.gov (United States)

    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.

  11. Vision and multiple sclerosis.

    Science.gov (United States)

    Hickman, Simon J; Raoof, Naz; McLean, Rebecca J; Gottlob, Irene

    2014-01-01

    Multiple sclerosis can affect vision in many ways, including optic neuritis, chronic optic neuropathy, retrochiasmal visual field defects, higher order cortical processing, double vision, nystagmus and also by related ocular conditions such as uveitis. There are also side effects from recently introduced multiple sclerosis treatments that can affect vision. This review will discuss all these aspects and how they come together to cause visual symptoms. It will then focus on practical aspects of how to recognise when there is a vision problem in a multiple sclerosis patient and on what treatments are available to improve vision.

  12. Computational approaches to vision

    Science.gov (United States)

    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.

  13. The colour of pain: can patients use colour to describe osteoarthritis pain?

    Science.gov (United States)

    Wylde, Vikki; Wells, Victoria; Dixon, Samantha; Gooberman-Hill, Rachael

    2014-03-01

    The aim of the present study was to explore patients' views on the acceptability and feasibility of using colour to describe osteoarthritis (OA) pain, and whether colour could be used to communicate pain to healthcare professionals. Six group interviews were conducted with 17 patients with knee OA. Discussion topics included first impressions about using colour to describe pain, whether participants could associate their pain with colour, how colours related to changes to intensity and different pain qualities, and whether they could envisage using colour to describe pain to healthcare professionals. The group interviews indicated that, although the idea of using colour was generally acceptable, it did not suit all participants as a way of describing their pain. The majority of participants chose red to describe high-intensity pain; the reasons given were because red symbolized inflammation, fire, anger and the stop signal in a traffic light system. Colours used to describe the absence of pain were chosen because of their association with positive emotional feelings, such as purity, calmness and happiness. A range of colours was chosen to represent changes in pain intensity. Aching pain was consistently identified as being associated with colours such as grey or black, whereas sharp pain was described using a wider selection of colours. The majority of participants thought that they would be able to use colour to describe their pain to healthcare professionals, although issues around the interpretability and standardization of colour were raised. For some patients, using colour to describe their pain experience may be a useful tool to improve doctor-patient communication. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Acquired color vision deficiency.

    Science.gov (United States)

    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.

  15. Novel applications of hyperstereo vision

    Science.gov (United States)

    Watkins, Wendell R.; Jordan, Jay B.; Trivedi, Mohan M.

    1997-09-01

    Recent stereo vision experiments show potential in enhancing vehicular navigation, target acquisition, and optical turbulence mitigation. The experiments involved the use of stereo vision headsets connected to visible and 8-12 micrometers IR imagers. The imagers were separated by up to 50 m and equipped with telescopes for viewing at ranges of tens of meters up to 4 km. The important findings were: (1) human viewers were able to discern terrain undulations for obstacle avoidance, (2) human viewers were able to detect depth features within the scenes that enhanced the target acquisition process over using monocular viewing,and (3) human viewers noted appreciable reduction in the distortion effects of optical turbulence over that observed through a single monocular channel. For navigation, stereo goggles were developed for headset display and simultaneous direct vision for vehicular navigation enhancement. For detection, the depth cues can be used to detect even salient target features. For optical turbulence, the human mechanisms of fusing two views into a single perceived scene can be used to provide nearly undistorted perception. These experiments show significant improvement for many applications.

  16. ENVIRONMENTAL JUSTICE MOVEMENTS AND GANDHI’S ECOLOGICAL VISION: A STUDY ON HUMAN RIGHTS VIOLATION BY DEVELOPMENTAL PROJECTS IN ODISHA

    Directory of Open Access Journals (Sweden)

    Braja Kishore Sahoo

    2016-01-01

    Full Text Available The state continues to be the key institution around which struggles for environmental justice in India are articulated. Its dominant role in the economy and its hierarchical, authoritarian and legitimate role as arbiter of rights and resources, the violation of its own environmental laws or acts in ways inimical to environmental justice has been protected by indigenous people. In my paper, I draw on the theme of the protest movements against developmental projects which are rooted in the livelihood and survival of the common people and the violation of human rights. The threats of displacement, loss of livelihood, alienation from their own surroundings are catalysts for this strand of the movement. The indigenous peoples facing threats to their rights, lands and cultures are the major force behind the mobilization against the corporate, government, policies and other forces which threaten them to fragment, displace, assimilate or drive towards cultural disintegration. I describe the main aim of these movements are based around the re-scaling of development projects to the local level, the defense of common property resources and the restoration of participatory, community based forms of environmental management. Based on this perspective, I discuss how the peoples of Odisha protest against developmental projects particularly Neo-Gandhian activists incorporating the political thinking and practice practiced by Gandhiji.This research shows that protest movements against developmental projects in Odisha were by and large successful by incorporating procedural, corrective and social aspects of justice inherent in Gandhian ecological ideas.

  17. Using digital colour to increase the realistic appearance of SEM micrographs of bloodstains.

    Science.gov (United States)

    Hortolà, Policarp

    2010-10-01

    Although in the scientific-research literature the micrographs from scanning electron microscopes (SEMs) are usually displayed in greyscale, the potential of colour resources provided by the SEM-coupled image-acquiring systems and, subsidiarily, by image-manipulation free softwares deserves be explored as a tool for colouring SEM micrographs of bloodstains. After acquiring greyscale SEM micrographs of a (dark red to the naked eye) human blood smear on grey chert, they were manually obtained in red tone using both the SEM-coupled image-acquiring system and an image-manipulation free software, as well as they were automatically generated in thermal tone using the SEM-coupled system. Red images obtained by the SEM-coupled system demonstrated lower visual-discrimination capability than the other coloured images, whereas those in red generated by the free software rendered better magnitude of scopic information than the red images generated by the SEM-coupled system. Thermal-tone images, although were further from the real sample colour than the red ones, not only increased their realistic appearance over the greyscale images, but also yielded the best visual-discrimination capability among all the coloured SEM micrographs, and fairly enhanced the relief effect of the SEM micrographs over both the greyscale and the red images. The application of digital colour by means of the facilities provided by an SEM-coupled image-acquiring system or, when required, by an image-manipulation free software provides a user-friendly, quick and inexpensive way of obtaining coloured SEM micrographs of bloodstains, avoiding to do sophisticated, time-consuming colouring procedures. Although this work was focused on bloodstains, well probably other monochromatic or quasi-monochromatic samples are also susceptible of increasing their realistic appearance by colouring them using the simple methods utilized in this study.

  18. The “seven-coloured earth” of Chamarel, Mauritius

    Science.gov (United States)

    Sheth, H. C.; Johnson, C. P.; Ollier, C. D.

    2010-04-01

    The "seven-coloured earth" of Chamarel is a geological curiosity and a major tourist attraction of Mauritius. This is a small (˜7500 m 2) area of strikingly bare landscape showing well-developed rills and various shades of red, brown, grey, and purple. Curiously, it is located within a large, dense forest. Prevalent misconceptions are that the landscape formed due to a volcanic eruption, or from volcanic ash. Whereas the bedrock is undoubtedly an old volcanic rock (basalt), the colours are due to weathering of the basalt and the formation of secondary iron oxides and hydroxides in it, and the rilling is a result of deforestation and sheet erosion, i.e., human modification of the landscape. Such features, inadequately described in the literature so far, also occur in Papua New Guinea, and may be common in tropical, high-rainfall regions with volcanic bedrock.

  19. Colour and lighting in hospital design

    Science.gov (United States)

    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'.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Individual colour patches as multicomponent signals.

    Science.gov (United States)

    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

  3. Oxygenated-blood colour change thresholds for perceived facial redness, health, and attractiveness.

    Directory of Open Access Journals (Sweden)

    Daniel E Re

    Full Text Available Blood oxygenation level is associated with cardiovascular fitness, and raising oxygenated blood colouration in human faces increases perceived health. The current study used a two-alternative forced choice (2AFC psychophysics design to quantify the oxygenated blood colour (redness change threshold required to affect perception of facial colour, health and attractiveness. Detection thresholds for colour judgments were lower than those for health and attractiveness, which did not differ. The results suggest redness preferences do not reflect a sensory bias, rather preferences may be based on accurate indications of health status. Furthermore, results suggest perceived health and attractiveness may be perceptually equivalent when they are assessed based on facial redness. Appearance-based motivation for lifestyle change can be effective; thus future studies could assess the degree to which cardiovascular fitness increases face redness and could quantify changes in aerobic exercise needed to increase facial attractiveness.

  4. Natural ingredients for colouring and styling.

    Science.gov (United States)

    Dweck, A C

    2002-10-01

    This paper examines some of the existing methods for colouring the hair and skin using natural material (such as henna) and proposes a parallel technology that exists in the dyeing of wool and fabrics to extend the colour range. Many of the listed plants and their derivatives are not found in Annex IV of the Cosmetic Directive and may not be used as colours; however, they do have other properties which may justify their inclusion into a product, for example, as astringent or anti-inflammatory agents. The paper concludes with some reported antigreying and hair styling preparations cited in the literature.

  5. Colour in visualisation for computational fluid dynamics

    Science.gov (United States)

    Kinnear, David; Atherton, Mark; Collins, Michael; Dokhan, Jason; Karayiannis, Tassos

    2006-06-01

    Colour is used in computational fluid dynamic (CFD) simulations in two key ways. First it is used to visualise the geometry and allow the engineer to be confident that the model constructed is a good representation of the engineering situation. Once an analysis has been completed, colour is used in post-processing the data from the simulations to illustrate the complex fluid mechanic phenomena under investigation. This paper describes these two uses of colour and provides some examples to illustrate the key visualisation approaches used in CFD.

  6. Availability of vision and tactile gating: vision enhances tactile sensitivity.

    Science.gov (United States)

    Colino, Francisco L; Lee, Ji-Hang; Binsted, Gordon

    2017-01-01

    A multitude of events bombard our sensory systems at every moment of our lives. Thus, it is important for the sensory and motor cortices to gate unimportant events. Tactile suppression is a well-known phenomenon defined as a reduced ability to detect tactile events on the skin before and during movement. Previous experiments (Buckingham et al. in Exp Brain Res 201(3):411-419, 2010; Colino et al. in Physiol Rep 2(3):e00267, 2014) found detection rates decrease just prior to and during finger abduction and decrease according to the proximity of the moving effector. However, what effect does vision have on tactile gating? There is ample evidence (see Serino and Haggard in Neurosci Biobehav Rev 34:224-236, 2010) observing increased tactile acuity when participants see their limbs. The present study examined how tactile detection changes in response to visual condition (vision/no vision). Ten human participants used their right hand to reach and grasp a cylinder. Tactors were attached to the index finger and the forearm of both the right and left arm and vibrated at various epochs relative to a "go" tone. Results replicate previous findings from our laboratory (Colino et al. in Physiol Rep 2(3):e00267, 2014). Also, tactile acuity decreased when participants did not have vision. These results indicate that the vision affects the somatosensation via inputs from parietal areas (Konen and Haggard in Cereb Cortex 24(2):501-507, 2014) but does so in a reach-to-grasp context.

  7. Mathematical leadership vision.

    Science.gov (United States)

    Hamburger, Y A

    2000-11-01

    This article is an analysis of a new type of leadership vision, the kind of vision that is becoming increasingly pervasive among leaders in the modern world. This vision appears to offer a new horizon, whereas, in fact it delivers to its target audience a finely tuned version of the already existing ambitions and aspirations of the target audience. The leader, with advisors, has examined the target audience and has used the results of extensive research and statistical methods concerning the group to form a picture of its members' lifestyles and values. On the basis of this information, the leader has built a "vision." The vision is intended to create an impression of a charismatic and transformational leader when, in fact, it is merely a response. The systemic, arithmetic, and statistical methods employed in this operation have led to the coining of the terms mathematical leader and mathematical vision.

  8. Galaxy And Mass Assembly (GAMA): Galaxy colour gradients versus colour, structure and luminosity

    CERN Document Server

    Kennedy, Rebecca; Häußler, Boris; Brough, Sarah; Holwerda, Benne; Hopkins, Andrew M; Vika, Marina; Vulcani, Benedetta

    2016-01-01

    Using single-component fits to SDSS/UKIDSS images of galaxies in the G09 region of the GAMA survey we study radial colour gradients across the galaxy population. We use the multiwavelength information provided by MegaMorph analysis of galaxy light profiles to calculate intrinsic colour gradients, and divide into six subsamples split by overall S\\'{e}rsic index ($n$) and galaxy colour. We find a bimodality in the colour gradients of high- and low-$n$ galaxies in all wavebands, which varies with overall galaxy luminosity. Global trends in colour gradients therefore result from combining the contrasting behaviour of a number of different galaxy populations. The ubiquity of strong negative colour gradients supports the picture of inside-out growth through gas accretion for blue, low-$n$ galaxies, and through dry minor mergers for red, high-$n$ galaxies. An exception is the blue high-n population, with properties indicative of dissipative major mergers.

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

    Science.gov (United States)

    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.

  10. Vision Deficits in Adults with Down Syndrome

    Science.gov (United States)

    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

  11. FPGA Vision Data Architecture

    Science.gov (United States)

    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.

  12. STEGANALYSIS USING COLOUR MODEL CONVERSION

    Directory of Open Access Journals (Sweden)

    P.Thiyagarajan

    2012-01-01

    Full Text Available The major threat in cyber crime for digital forensic examiner is to identify, analyze and interpret theconcealed information inside digital medium such as image, audio and video. There are strong indicationsthat hiding information inside digital medium has been used for planning criminal activities. In this way, itis important to develop a steganalysis technique which detects the existence of hidden messages insidedigital medium. This paper focuses on universal image steganalysis method which uses RGB to HSI colourmodel conversion. Any Universal Steganalysis algorithm developed should be tested with various stegoimagesto prove its efficiency. The developed Universal Steganalysis algorithm is tested in stego-imagedatabase which is obtained by implementing various RGB Least Significant Bit Steganographic algorithms.Though there are many stego-image sources available on the internet it lacks in the information such ashow many rows has been infected by the steganography algorithms, how many bits have been modified andwhich channel has been affected. These parameters are important for Steganalysis algorithms and it helpsto rate its efficiency. Proposed Steganalysis using Colour Model has been tested with our Image Databaseand the results were affirmative.

  13. Steganalysis Using Colour Model Conversion

    Directory of Open Access Journals (Sweden)

    P.Thiyagarajan

    2011-12-01

    Full Text Available The major threat in cyber crime for digital forensic examiner is to identify, analyze and interpret theconcealed information inside digital medium such as image, audio and video. There are strong indicationsthat hiding information inside digital medium has been used for planning criminal activities. In this way, itis important to develop a steganalysis technique which detects the existence of hidden messages insidedigital medium. This paper focuses on universal image steganalysis method which uses RGB to HSI colourmodel conversion. Any Universal Steganalysis algorithm developed should be tested with various stegoimagesto prove its efficiency. The developed Universal Steganalysis algorithm is tested in stego-imagedatabase which is obtained by implementing various RGB Least Significant Bit Steganographic algorithms.Though there are many stego-image sources available on the internet it lacks in the information such ashow many rows has been infected by the steganography algorithms, how many bits have been modified andwhich channel has been affected. These parameters are important for Steganalysis algorithms and it helpsto rate its efficiency. Proposed Steganalysis using Colour Model has been tested with our Image Databaseand the results were affirmative.

  14. SATISFIABILITY METHODS FOR COLOURING GRAPHS

    Directory of Open Access Journals (Sweden)

    Munmun Dey

    2013-02-01

    Full Text Available The graph colouring problem can be solved using methods based on Satisfiability (SAT. An instance of the problem is defined by a Boolean expression written using Boolean variables and the logical connectives AND, OR and NOT. It has to be determined whether there is an assignment of TRUE and FALSE values to the variables that makes the entire expression true.A SAT problem is syntactically and semantically quite simple. Many Constraint Satisfaction Problems (CSPsin AI and OR can be formulated in SAT. These make use of two kinds of searchalgorithms: Deterministic and Randomized.It has been found that deterministic methods when run on hard CSP instances are frequently very slow in execution.A deterministic method always outputs a solution in the end, but it can take an enormous amount of time to do so.This has led to the development of randomized search algorithms like GSAT, which are typically based on local (i.e., neighbourhood search. Such methodshave been applied very successfully to find good solutions to hard decision problems

  15. Measuring Vision in Children

    Directory of Open Access Journals (Sweden)

    Petra Verweyen

    2004-01-01

    Full Text Available Measuring vision in children is a special skill requiring time, patience and understanding. Methods should be adapted to the child’s age, abilities, knowledge and experience. Young children are not able to describe their vision or explain their visual symptoms. Through observation, and with information from the mother or guardian, functional vision can be evaluated. While testing and observing children, an experienced assessor notices their responses to visual stimuli. These must be compared with the expected functional vision for children of the same age and abilities, so it is important to know the normal visual development.

  16. How to pass higher English colour

    CERN Document Server

    Bridges, Ann

    2009-01-01

    How to Pass is the Number 1 revision series for Scottish qualifications across the three examination levels of Standard Grade, Intermediate and Higher! Second editions of the books present all of the material in full colour for the first time.

  17. Colour Management as a Precondition of Quality

    Directory of Open Access Journals (Sweden)

    Stefan Brues

    2004-12-01

    Full Text Available Colour management technology has reached a high level of maturity. Only ten years after it first appeared on the market, ICC colour profiles have become indispensable in modern premedia. It can be said without exaggeration that colour management has revolutionised digital proof printing. A whole range of newcomers in the print industry supplier community offer an intelligent combination of a PostScript RIP with integral colour management functions. The quality of these low-priced proofing systems has now reached such a high level that even discerning customers accept such digital proofs as contract proofs. Modular proofing solutions are regularly to be found among the leaders in the digital proofer tests.Working with colour profiles and profiled workflows is still a major problem area. It is no mere chance that notably digital proofing is the field in which users work with colour profiles in virtually all systems, since applications here are locally limited.An important step for the widespread use of colour management technology is the now very extensive implementation of ICC mechanisms in application programs such as Adobe Photoshop. Version 7 is regarded as a model of well thought-out ICC-based colour management implementation. As Microsoft has neglected the ICC standard in recent years, Adobe has created its own colour management interface, called ACE. Based on the ICC standard, it is regarded by many experts as a reference implementation. Adobe products, which are so important for the graphic arts industry, now contain a standard colour management platform across all supported operating systems. Incompatibilities at system level can now be virtually ruled out, at least across the Adobe product line, including the important interfaces with PostScript and PDF.Modern prepress technology is set to move ever further away from exclusive print production for standardised offset print. Multiple use of production data is still at an early stage

  18. Salience of Primary and Secondary Colours in Infancy

    Science.gov (United States)

    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…

  19. Salience of Primary and Secondary Colours in Infancy

    Science.gov (United States)

    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…

  20. Plants and colour: Flowers and pollination

    Science.gov (United States)

    Miller, Renee; Owens, Simon J.; Rørslett, Bjørn

    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 functions—they 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.