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.

From spectral information to animal colour vision: experiments and concepts

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Kelber, Almut; Osorio, Daniel

2010-01-01

Many animals use the spectral distribution of light to guide behaviour, but whether they have colour vision has been debated for over a century. Our strong subjective experience of colour and the fact that human vision is the paradigm for colour science inevitably raises the question of how we compare with other species. This article outlines four grades of ‘colour vision’ that can be related to the behavioural uses of spectral information, and perhaps to the underlying mechanisms. In the fir...

Blue-yellow colour vision impairment and cognitive deficits in occasional and dependent stimulant users.

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Hulka, Lea M; Wagner, Michael; Preller, Katrin H; Jenni, Daniela; Quednow, Boris B

2013-04-01

Specific blue-yellow colour vision impairment has been reported in dependent cocaine users and it was postulated that drug-induced changes in retinal dopamine neurotransmission are responsible. However, it is unclear whether these changes are confined to chronic cocaine users, whether they are specific for dopaminergic stimulants such as cocaine and amphetamine and whether they are related to cognitive functions such as working memory, encoding and consolidation. In 47 occasional and 29 dependent cocaine users, 23 MDMA (commonly known as 'ecstasy') users and 47 stimulant-naive controls, colour vision discrimination was measured with the Lanthony Desaturated Panel D-15 Test and memory performance with the Auditory Verbal Learning Test. Both occasional and dependent cocaine users showed higher colour confusion indices than controls. Users of the serotonergic stimulant MDMA (26%), occasional (30%) and dependent cocaine users (34%) exhibited more frequent blue-yellow colour vision disorders compared to controls (9%). Inferior performance of MDMA users was caused by a subgroup with high amphetamine co-use (55%), while MDMA use alone was not associated with decreased blue-yellow discrimination (0%). Cognitive performance was worse in cocaine users with colour vision disorder compared to users and controls with intact colour vision and both colour vision impairment and cognitive deficits were related to cocaine use. Occasional cocaine and amphetamine use might induce blue-yellow colour vision impairment, whereas the serotonergic stimulant MDMA does not impair colour vision. The association between colour vision impairment and cognitive deficits in cocaine users may reflect that retinal and cerebral dopamine alterations are linked to a certain degree.

Colour-grapheme synaesthesia affects binocular vision

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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.

A review of the evolution of animal colour vision and visual communication signals.

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Osorio, D; Vorobyev, M

2008-09-01

The visual displays of animals and plants are often colourful, and colour vision allows animals to respond to these signals as they forage for food, choose mates and so-forth. This article discusses the evolutionary relationship between photoreceptor spectral sensitivities of four groups of land animals--birds, butterflies, primates and hymenopteran insects (bees and wasps)--, the colour signals that are relevant to them, and how understanding is informed by models of spectral coding and colour vision. Although the spectral sensitivities of photoreceptors are known to vary adaptively under natural selection there is little evidence that those of hymenopterans, birds and primates are specifically adapted to the reflectance spectra of food plants or animal visual signals. On the other hand, the colours of fruit, flowers and feathers may have evolved to be more discriminable for the colour vision of their natural receivers than for other groups of animals. Butterflies are unusual in that they have enjoyed a major radiation in receptor numbers and spectral sensitivities. The reasons for the radiation and diversity of butterfly colour vision remain unknown, but may include their need to find food plants and to select mates.

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

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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.

Quantum photoelectron effects in the eye retina and development of colour vision theory

International Nuclear Information System (INIS)

Kremkov, M.V.

2011-01-01

The quantum semiconductor mechanism of the colour vision of mans is created. The mechanism is based on quantum effects under influence of light waves exciting valence electrons in different microelement's atoms (Zn, Cu, Fe, Co, P, Br, Se, et al.) that are presented in the photoreceptor's cells of the eye retina (columns and retorts) with the quasi-periodical disks structure. The microelement concentrations correspond to the impurity atom amount in semiconductors, and the photoelectron's current passes out its signal to the vision nerve. The mechanism explains existence of the man colour-blindness, degradation of the vision sensitivity with the man's age and other peculiarities of the colour vision. (authors)

Genetics Home Reference: color vision deficiency

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... my area? Other Names for This Condition color blindness color vision defects defective color vision vision defect, color ... Perception KidsHealth from the Nemours Foundation MalaCards: color blindness MalaCards: color vision deficiency Orphanet: Blue cone monochromatism Orphanet: NON ...

Binary pressure-sensitive paint measurements using miniaturised, colour, machine vision cameras

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Quinn, Mark Kenneth

2018-05-01

Recent advances in machine vision technology and capability have led to machine vision cameras becoming applicable for scientific imaging. This study aims to demonstrate the applicability of machine vision colour cameras for the measurement of dual-component pressure-sensitive paint (PSP). The presence of a second luminophore component in the PSP mixture significantly reduces its inherent temperature sensitivity, increasing its applicability at low speeds. All of the devices tested are smaller than the cooled CCD cameras traditionally used and most are of significantly lower cost, thereby increasing the accessibility of such technology and techniques. Comparisons between three machine vision cameras, a three CCD camera, and a commercially available specialist PSP camera are made on a range of parameters, and a detailed PSP calibration is conducted in a static calibration chamber. The findings demonstrate that colour machine vision cameras can be used for quantitative, dual-component, pressure measurements. These results give rise to the possibility of performing on-board dual-component PSP measurements in wind tunnels or on real flight/road vehicles.

Is colour cognitive?

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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.

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

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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).

iPad colour vision apps for dyschromatopsia screening.

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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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prevalence of color vision deficiency among arc welders.

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Heydarian, Samira; Mahjoob, Monireh; Gholami, Ahmad; Veysi, Sajjad; Mohammadi, Morteza

This study was performed to investigate whether occupationally related color vision deficiency can occur from welding. A total of 50 male welders, who had been working as welders for at least 4 years, were randomly selected as case group, and 50 age matched non-welder men, who lived in the same area, were regarded as control group. Color vision was assessed using the Lanthony desatured panel D-15 test. The test was performed under the daylight fluorescent lamp with a spectral distribution of energy with a color temperature of 6500K and a color rendering index of 94 that provided 1000lx on the work plane. The test was carried out monocularly and no time limit was imposed. All data analysis were performed using SPSS, version 22. The prevalence of dyschromatopsia among welders was 15% which was statistically higher than that of nonwelder group (2%) (p=0.001). Among welders with dyschromatopsia, color vision deficiency in 72.7% of cases was monocular. There was positive relationship between the employment length and color vision loss (p=0.04). Similarly, a significant correlation was found between the prevalence of color vision deficiency and average working hours of welding a day (p=0.025). Chronic exposure to welding light may cause color vision deficiency. The damage depends on the exposure duration and the length of their employment as welders. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

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

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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.

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. © 2014. Published by The Company of Biologists Ltd.

A randomised comparison between an inexpensive, general-purpose headlight and a purpose-built surgical headlight on users' visual acuity and colour vision.

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Street, I; Sayles, M; Nistor, M; McRae, A R

2014-02-01

To determine if there are any differences in near visual acuity and colour vision between an inexpensive general-purpose light emitting diode (LED) headlight and a purpose-built surgical LED headlight. A prospective study was conducted sequentially comparing near visual acuity and colour vision, the headlights being tested in random order, in a testing room with a constant minimal amount of background light. The participants were NHS employee volunteers, with self-declared normal (or corrected) vision, working in occupations requiring full literacy. For visual acuity, outcome was measured by recording the smallest font legible when using each headlight when the subject read a near visual acuity test card. For colour vision, the outcome was passing or failing the Ishihara test. There was no statistically significant difference between the general-purpose and the purpose-built headlights in users' near visual acuity or colour vision.

Colour vision abnormality as the only manifestation of normal pressure hydrocephalus.

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Asensio-Sánchez, V M; Martín-Prieto, A

2018-01-01

The case is presented of a 73-year-old male patient who referred to having black and white vision. Computed tomography showed normal pressure hydrocephalus (NPH). Magnetic resonance imaging was not performed because the patient refused to undergo further examinations. Achromatopsia may be the first or only NPH symptom. It may be prudent to ask patients with NPH regarding colour vision. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Memory colours affect colour appearance.

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Witzel, Christoph; Olkkonen, Maria; Gegenfurtner, Karl R

2016-01-01

Memory colour effects show that colour perception is affected by memory and prior knowledge and hence by cognition. None of Firestone & Scholl's (F&S's) potential pitfalls apply to our work on memory colours. We present a Bayesian model of colour appearance to illustrate that an interaction between perception and memory is plausible from the perspective of vision science.

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

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

2016-07-14

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

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

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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.

Colour vision and response bias in a coral reef fish.

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

2013-08-01

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

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.

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Abu Bakar, Nurul Farhana; Chen, Ai-Hong

2014-02-01

Children with learning disabilities might have difficulties to communicate effectively and give reliable responses as required in various visual function testing procedures. 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. 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. 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 learning disabilities. Modifications of vision testing procedures are essential for children with learning disabilities.

Colour cues for leaf food selection by long-tailed macaques (Macaca fascicularis) with a new suggestion for the evolution of trichromatic colour vision.

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Lucas, P W; Darvell, B W; Lee, P K; Yuen, T D; Choong, M F

1998-01-01

Leaf colour, size and toughness were investigated in five plant species important in the diet of Macaca fascicularis in Singapore. Leaf colour and size were examined as potential visual cues for food selection, whereas toughness mirrored fibre content, the inverse of food quality. As leaves matured, they changed colour and toughened. Leaf lightness and yellowness were strongly negatively correlated with toughness, but variation in both the red-green axis of the CIE Lab colour space and leaf size were not. Leaves selected as food by the macaques were distinguished by being very light, yellow to slightly green. Some leaves were dappled with red. The literature suggests that these leaves are relatively rich in protein without being tough and therefore would be sought after by primates. We argue that leaf colour is an important indicator of the nutritive value of leaves. Trichromatic vision is an important advantage in finding those palatable leaves that are dappled red. These would appear dark to dichromatic primates and be deceptive by making leaves look older (lower in quality) than they actually are. This would decrease the perceived window of feeding opportunity for such primates who would be at a disadvantage in trying to find these leaves. It is possible that trichromatic vision in catarrhine primates may have originally evolved for the detection of red coloration in the leaves of shade-tolerant tropical plants, enabling the better exploitation of a food resource.

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

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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.

Visual Colour-Impulse Stimulation Treatment of Hyperactivity with Deficiency of Attention at Children

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I.E. Рoverennova

2009-06-01

Full Text Available The causes of occurrence and development of the syndrome of hyperactivity with deficiency of attention at children аre considered. The diagnostic complex for application at patients with the given syndrome in conditions of polyclinic is under the study. The new technique in complex treatment of hyperactivity with deficiency of attention with application of visual colour-impulse stimulation for easing emotional tension (“ASIR” is proposed.

Do dichromats see colours in this way? Assessing simulation tools without colorimetric measurements.

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Lillo Jover, Julio A; Álvaro Llorente, Leticia; Moreira Villegas, Humberto; Melnikova, Anna

2016-11-01

Simulcheck evaluates Colour Simulation Tools (CSTs, they transform colours to mimic those seen by colour vision deficients). Two CSTs (Variantor and Coblis) were used to know if the standard Simulcheck version (direct measurement based, DMB) can be substituted by another (RGB values based) not requiring sophisticated measurement instruments. Ten normal trichromats performed the two psychophysical tasks included in the Simulcheck method. The Pseudoachromatic Stimuli Identification task provided the h uv (hue angle) values of the pseudoachromatic stimuli: colours seen as red or green by normal trichromats but as grey by colour deficient people. The Minimum Achromatic Contrast task was used to compute the L R (relative luminance) values of the pseudoachromatic stimuli. Simulcheck DMB version showed that Variantor was accurate to simulate protanopia but neither Variantor nor Coblis were accurate to simulate deuteranopia. Simulcheck RGB version provided accurate h uv values, so this variable can be adequately estimated when lacking a colorimeter —an expensive and unusual apparatus—. Contrary, the inaccuracy of the L R estimations provided by Simulcheck RGB version makes it advisable to compute this variable from the measurements performed with a photometer, a cheap and easy to find apparatus.

Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabrication.

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Zhang, Min; Li, Songjing

2016-01-01

In this work, liquid colour-changing lenses for vision protection, camouflage and optical filtering are developed by circulating colour liquids through microfluidic channels on the lenses manually. Soft lithography technology is applied to fabricate the silicone liquid colour-changing layers with microfluidic channels on the lenses instead of mechanical machining. To increase the hardness and abrasion resistance of the silicone colour-changing layers on the lenses, proper fabrication parameters such as 6:1 (mass ration) mixing proportion and 100 °C curing temperature for 2 h are approved for better soft lithography process of the lenses. Meanwhile, a new surface treatment for the irreversible bonding of silicone colour-changing layer with optical resin (CR39) substrate lens by using 5 % (volume ratio) 3-Aminopropyltriethoxysilane solution is proposed. Vision protection, camouflage and optical filtering functions of the lenses are investigated with different designs of the channels and multi-layer structures. Each application can not only well achieve their functional demands, but also shows the advantages of functional flexibility, rapid prototyping and good controllability compared with traditional ways. Besides optometry, some other designs and applications of the lenses are proposed for potential utility in the future.

Visual search in the real world: Color vision deficiency affects peripheral guidance, but leaves foveal verification largely unaffected

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Günter eKugler

2015-12-01

Full Text Available Background: People with color vision deficiencies report numerous limitations in daily life. However, they use basic color terms systematically and in a similar manner as people with people with normal color vision. We hypothesize that a possible explanation for this discrepancy between color perception and behavioral consequences might be found in the gaze behavior of people with color vision deficiency.Methods: A group of participants with color vision deficiencies and a control group performed several search tasks in a naturalistic setting on a lawn.Results: Search performance was similar in both groups in a color-unrelated search task as well as in a search for yellow targets. While searching for red targets, color vision deficient participants exhibited a strongly degraded performance. This was closely matched by the number of fixations on red objects shown by the two groups. Importantly, once they fixated a target, participants with color vision deficiencies exhibited only few identification errors. Conclusions: Participants with color vision deficiencies are not able to enhance their search for red targets on a (green lawn by an efficient guiding mechanism. The data indicate that the impaired guiding is the main influence on search performance, while foveal identification (verification largely unaffected.

Repeatability indices for the Adams D-15 test for colour-normal and colour-defective adults.

Science.gov (United States)

Hovis, Jeffery K; Ramaswamy, Shankaran; Anderson, Matthew

2004-07-01

The Adams desaturated D-15 test was administered to individuals with normal colour vision or with congenital red-green colour vision defects to establish the repeatability of the test. One hundred subjects with normal colour vision and 64 subjects with defective colour vision participated in the study. Results were analysed from two different sessions to determine the repeatability of the test for different pass/fail criteria. The test was scored using both visual inspection of the score sheet and the modified Colour Difference Vector analysis (CDV) program. For both subject groups, the repeatability was lowest when a perfect arrangement was required for a pass and improved as more errors were allowed. The improvement in repeatability was greatest as the failure criterion changed from 'any mistake' to 'more than two crossings'. The kappa coefficient for the reliability of the defect classification was 0.38 for visual inspection and 0.59 for the CDV analysis. All the protans who failed the test at both sessions were classified correctly. Approximately 98 per cent of the colour-normals and 82 per cent of the colour-defectives would have the same pass/fail outcome on the Adams D-15 test conducted several days apart when the failure criterion was either one or more or two or more crossings. Individuals who make less than four crossings on the Adams D-15 should repeat the test to ensure confidence in the pass/fail result.

Colour contribution to children's wayfinding in school environments

Science.gov (United States)

Helvacıoǧlu, Elif; Olguntürk, Nilgün

2011-03-01

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

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

Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

Science.gov (United States)

Goffeng, Lars Ole; Kjuus, Helge; Heier, Mona Skard; Alvestrand, Monica; Ulvestad, Bente; Skaug, Vidar

2008-01-01

The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2-10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group. Information on exposure and background variables was obtained for all participants from a questionnaire. Visual light sensitivity threshold was measured using Humphrey Visual Field Static Perimeter 740, program 30-2 Fastpack, with red stimuli on white background, and colour vision, using Lanthony D-15 Desaturated Color test. Based on D-15d test results, colour confusion index (CCI), and a severity index (C-index) was calculated. The exposed group had a significantly higher threshold for detecting single stimuli in all parts of the inner 30 degrees of the visual field compared to the control group. The foveal threshold group difference was 1.4 dB (p=0.002) (mean value, both eyes). On the Lanthony 15 Hue Desaturated test, the exposed subjects made more errors in sorting blue colours, and a statistically significant increase in C-index was observed. Surrogate measures for duration and intensity of exposure gave no further improvement of the model. The results indicate slightly reduced light sensitivity and reduced colour discrimination among the exposed subjects compared to the controls. The findings may be due to previous exposure to acrylamide containing grouts among the tunnel workers.

Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).

Science.gov (United States)

Barry, John A; Mollan, Susan; Burdon, Michael A; Jenkins, Michelle; Denniston, Alastair K

2017-10-02

Congenital colour vision deficiency (CVD), commonly called 'colour blindness', affects around 8% of men and 0.4% of women. Although many aspects of health (e.g. change in colour of urine) and healthcare (e.g. coloured medication, colour-coded diagnostic tests), and modern life depend upon colour coding (e.g. graphs, maps, signals), the impact of colour blindness on everyday life is not generally considered a topic of importance. This study is the first to create and validate a questionnaire measuring the quality of life (QoL) impact of being colour blind. This study consisted of two phases. Firstly, the questionnaire design and development phase was led by an expert panel and piloted on a focus group. Secondly, an online sample of 128 men and 291 women filled in the questionnaire, and the psychometric properties of the questionnaire were analysed using principal components analysis (PCA). The scores of colour blind (CB) participants and normal-sighted controls, controlling for age and sex, were compared using matched t-tests. The PCA resulted in a questionnaire with three domains (or subscales): QoL for Health & Lifestyle, QoL for Work, and QoL for Emotions. Controlling for age, there was a significantly greater negative impact on QoL for CB people than normal-sighted controls in regards to confusion over colour in various aspects of their health (p = 5 × 10 -7 ), work (p = 1.3 × 10 -7 ), and emotional life (p = 6 × 10 -5 ). Colour blindness can significantly impact quality of life for health, emotions, and especially careers. The tool developed here could be useful in future clinical studies to measure changes in CBQoL in response to therapy in conditions where colour vision is affected. We also discuss ways in which everyday problems related to colour vision might be reduced, for example, workplaces could avoid colour coding where a non-colour alternative is possible.

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.

What do colour-blind people really see?

NARCIS (Netherlands)

Hogervorst, M.A.; Alferdinck, J.W.A.M.

2008-01-01

Problem: colour perception of dichromats (colour-blind persons) Background: Various models have been proposed (e. g. Walraven & Alferdinck, 1997; Brettel et al. , 1997) to model reduced colour vision of colour-blind people. It is clear that colour-blind people cannot distinguish certain object

Color Functionality Used in Visual Display for Occupational and Environmental Safety and Managing Color Vision Deficiency.

Science.gov (United States)

Ochiai, Nobuhisa; Kondo, Hiroyuki

2017-01-01

The effects of color perception are utilized in visual displays for the purpose of safety in the workplace and in daily life. These effects, generally known as color functionality, are divided into four classifications: visibility, legibility, conspicuity and discriminability. This article focuses on the relationship between the color functionality of color schemes used in visual displays for occupational and environmental safety and color vision deficiency (particularly congenital red-green color deficiency), a critical issue in ophthalmology, and examines the effects of color functionality on the perception of the color red in individuals with protan defects. Due to abrupt system reforms, current Japanese clinical ophthalmology finds itself in a situation where it is insufficiently prepared to handle congenital red-green color deficiencies. Indeed, occupational problems caused by color vision deficiencies have been almost completely neglected, and are an occupational safety and health concern that will need to be solved in the future. This report will present the guidelines for the color vision testing established by the British Health and Safety Executive (HSE), a pioneering example of a model meant to solve these problems. Issues relating to the creation of guidelines adapted to Japanese clinical ophthalmology will also be examined, and we will discuss ways to utilize color functionality used in visual displays for occupational and environmental safety to help manage color vision deficiency.

Spectral sensitivity of a colour changing spider.

Science.gov (United States)

Defrize, Jérémy; Lazzari, Claudio R; Warrant, Eric J; Casas, Jérôme

2011-04-01

Vision plays a paramount role in some spider families such as the Salticidae, Lycosidae and Thomisidae, as it is involved in prey hunting, orientation or choice of substrate. In the thomisid Misumena vatia, for which the substrate colour affects the body colour, vision seems to mediate morphological colour changes. However, nothing is known about which component of visual signals from the substrate might be perceived, nor whether M. vatia possesses the physiological basis for colour vision. The aim of this study is thus to investigate the vision of this spider species by measuring the spectral sensitivities of the different pairs of eyes using electrophysiological methods. Extra- and intracellular electrophysiological recordings combined with selective adaptation revealed the presence of two classes of photoreceptor cells, one sensitive in the UV region of the spectrum (around 340 nm) and one sensitive in the green (around 520 nm) regions in the four pairs of eyes. We conclude that M. vatia possesses the physiological potential to perceive both chromatic and achromatic components of the environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Colouring outside the lines

Science.gov (United States)

Commissariat, Tushna

2017-10-01

Walk into a bookshop today, or even a gift shop, and you will most likely come across an entire section of colouring books for adults. Visions of Numberland: a Colouring Journey Through the Mysteries of Maths by Alex Bellos and Edmund Harriss is one such book.

The effect of tinted spectacle lenses on contrast sensitivity and colour vision

Directory of Open Access Journals (Sweden)

M. Shaik

2013-12-01

The greater enhancement was for low spatial frequencies (LSF and least for high spatial frequencies (HSF. With all tints Grade C had the least enhancement for very HSF. Many subjects showed no change in CV with any of the lensesused. The grey tint showed greater enhancement of CV as the density increases. Blue and brown tints showed a similar trend with grade B enhancing CV the most while grade C resulted in theleast reduction of CV. Conclusion: Grade A, B, and C of blue, brown and grey tinted spectacle lenses do not alter colour vision significantly but for the selected levels of transmission of the tints used, contrast sensitivity can be improved to some extent.

Fundamentals of colour awareness: a literature review

Directory of Open Access Journals (Sweden)

A. Rubin

2005-12-01

Full Text Available A description of some of the basic or funda-mental aspects of the colour sensory mechanism will be provided here, based on modern ideas and literature, with reference specifically to the likely origins and evolution of colour vision.  The mo-lecular basis for colour awareness and the human colour pathway will also be considered in some detail. This paper intends to provide the theoreti-cal and philosophical basis for further papers that will introduce a modern and original computer- based  method  for  more  comprehensive  colour vision  assessment.    This  new  approach,  to  be fully described in later manuscripts, may contrib-ute towards improvements in understanding and knowledge of human colour perception and its measurement, still perhaps a relatively under-ex-plored or neglected field of study within optom-etry and ophthalmology.

Color Vision Deficiency and Color Blindness: An Introduction to the Problem.

Science.gov (United States)

Olsen, Mary Margaret; Harris, Kenneth R.

The paper examines issues concerned with the education and employment of individuals, primarily males, with color vision deficiency. After a brief introduction, the first chapter looks at adult problems such as employment areas in which the disability presents problems. The next chapter considers problems of children, noting the heavy use of color…

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness

Science.gov (United States)

Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B.; Franklin, Anna

2016-01-01

The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d’) and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object’s stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain. PMID:27023274

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness.

Science.gov (United States)

Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B; Franklin, Anna

2016-01-01

The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d') and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain.

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness.

Directory of Open Access Journals (Sweden)

Lewis Forder

Full Text Available The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry, detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d' and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain.

Object Knowledge Modulates Colour Appearance

Directory of Open Access Journals (Sweden)

Christoph Witzel

2011-01-01

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

Object knowledge modulates colour appearance

Science.gov (United States)

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

2011-01-01

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

A study of normal and defective colour vision

NARCIS (Netherlands)

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

1957-01-01

MEASUREMENTS were made of saturation discrimination of normal and colour defective subjects with illuminant A as reference colour. The colorimeter used in the experiments was of a special design developed for easy use by untrained persons. The results for normals are not quite in agreement with the

Universal Design: Supporting Students with Color Vision Deficiency (CVD) in Medical Education

Science.gov (United States)

Meeks, Lisa M.; Jain, Neera R.; Herzer, Kurt R.

2016-01-01

Color Vision Deficiency (CVD) is a commonly occurring condition in the general population. For medical students, it has the potential to create unique challenges in the classroom and clinical environments. Few studies have provided medical educators with comprehensive recommendations to assist students with CVD. This article presents a focused…

Supervised Object Class Colour Normalisation

DEFF Research Database (Denmark)

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

2013-01-01

. 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......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 their colours. We demonstrate the effectiveness of our method with qualitative and quantitative examples from the Caltech-101 data set and a real application of 3D pose estimation for robot grasping....

Exploring the functional nature of synaesthetic colour: Dissociations from colour perception and imagery.

Science.gov (United States)

Chiou, Rocco; Rich, Anina N; Rogers, Sebastian; Pearson, Joel

2018-08-01

Individuals with grapheme-colour synaesthesia experience anomalous colours when reading achromatic text. These unusual experiences have been said to resemble 'normal' colour perception or colour imagery, but studying the nature of synaesthesia remains difficult. In the present study, we report novel evidence that synaesthetic colour impacts conscious vision in a way that is different from both colour perception and imagery. Presenting 'normal' colour prior to binocular rivalry induces a location-dependent suppressive bias reflecting local habituation. By contrast, a grapheme that evokes synaesthetic colour induces a facilitatory bias reflecting priming that is not constrained to the inducing grapheme's location. This priming does not occur in non-synaesthetes and does not result from response bias. It is sensitive to diversion of visual attention away from the grapheme, but resistant to sensory perturbation, reflecting a reliance on cognitive rather than sensory mechanisms. Whereas colour imagery in non-synaesthetes causes local priming that relies on the locus of imagined colour, imagery in synaesthetes caused global priming not dependent on the locus of imagery. These data suggest a unique psychophysical profile of high-level colour processing in synaesthetes. Our novel findings and method will be critical to testing theories of synaesthesia and visual awareness. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessing the colour quality of LED sources

DEFF Research Database (Denmark)

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

2015-01-01

The CIE General Colour Rendering Index is currently the criterion used to describe and measure the colour-rendering properties of light sources. But over the past years, there has been increasing evidence of its limitations particularly its ability to predict the perceived colour quality of light...... 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...... (attractiveness/ preference) and colour difference estimations for both visual scenes. Forty-five observers with normal colour vision evaluated nine light sources at 3000 K, and 36 observers evaluated eight light sources at 4000 K. Our results indicate that perceived colour differences are better dealt...

Fundamentals of colour awareness: a literature review

OpenAIRE

A. Rubin

2005-01-01

A description of some of the basic or funda-mental aspects of the colour sensory mechanism will be provided here, based on modern ideas and literature, with reference specifically to the likely origins and evolution of colour vision.  The mo-lecular basis for colour awareness and the human colour pathway will also be considered in some detail. This paper intends to provide the theoreti-cal and philosophical basis for further papers that will introduce a modern and original computer- based  met...

Color vision deficiency compensation for Visual Processing Disorder using Hardy-Rand-Rittler test and color transformation

Science.gov (United States)

Balbin, Jessie R.; Pinugu, Jasmine Nadja J.; Bautista, Joshua Ian C.; Nebres, Pauline D.; Rey Hipolito, Cipriano M.; Santella, Jose Anthony A.

2017-06-01

Visual processing skill is used to gather visual information from environment however, there are cases that Visual Processing Disorder (VPD) occurs. The so called visual figure-ground discrimination is a type of VPD where color is one of the factors that contributes on this type. In line with this, color plays a vital role in everyday living, but individuals that have limited and inaccurate color perception suffers from Color Vision Deficiency (CVD) and still not aware on their case. To resolve this case, this study focuses on the design of KULAY, a Head-Mounted Display (HMD) device that can assess whether a user has a CVD or not thru the standard Hardy-Rand-Rittler (HRR) test. This test uses pattern recognition in order to evaluate the user. In addition, color vision deficiency simulation and color correction thru color transformation is also a concern of this research. This will enable people with normal color vision to know how color vision deficient perceives and vice-versa. For the accuracy of the simulated HRR assessment, its results were validated thru an actual assessment done by a doctor. Moreover, for the preciseness of color transformation, Structural Similarity Index Method (SSIM) was used to compare the simulated CVD images and the color corrected images to other reference sources. The output of the simulated HRR assessment and color transformation shows very promising results indicating effectiveness and efficiency of the study. Thus, due to its form factor and portability, this device is beneficial in the field of medicine and technology.

Forbidden Structures for Planar Perfect Consecutively Colourable Graphs

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Borowiecka-Olszewska Marta

2017-05-01

Full Text Available A consecutive colouring of a graph is a proper edge colouring with posi- tive integers in which the colours of edges incident with each vertex form an interval of integers. The idea of this colouring was introduced in 1987 by Asratian and Kamalian under the name of interval colouring. Sevast- janov showed that the corresponding decision problem is NP-complete even restricted to the class of bipartite graphs. We focus our attention on the class of consecutively colourable graphs whose all induced subgraphs are consecutively colourable, too. We call elements of this class perfect consecutively colourable to emphasise the conceptual similarity to perfect graphs. Obviously, the class of perfect consecutively colourable graphs is induced hereditary, so it can be characterized by the family of induced forbidden graphs. In this work we give a necessary and sufficient conditions that must be satisfied by the generalized Sevastjanov rosette to be an induced forbid- den graph for the class of perfect consecutively colourable graphs. Along the way, we show the exact values of the deficiency of all generalized Sevastjanov rosettes, which improves the earlier known estimating result. It should be mentioned that the deficiency of a graph measures its closeness to the class of consecutively colourable graphs. We motivate the investigation of graphs considered here by showing their connection to the class of planar perfect consecutively colourable graphs.

Fast Segmentation of Colour Apple Image under All-Weather Natural Conditions for Vision Recognition of Picking Robots

Directory of Open Access Journals (Sweden)

Wei Ji

2016-02-01

Full Text Available In order to resolve the poor real-time performance problem of the normalized cut (Ncut method in apple vision recognition of picking robots, a fast segmentation method of colour apple images based on the adaptive mean-shift and Ncut methods is proposed in this paper. Firstly, the traditional Ncut method based on pixels is changed into the Ncut method based on regions by the adaptive mean-shift initial segmenting. In this way, the number of peaks and edges in the image is dramatically reduced and the computation speed is improved. Secondly, the image is divided into regional maps by extracting the R-B colour feature, which not only reduces the quantity of regions, but also to some extent overcomes the effect on illumination. On this basis, every region map is expressed by a region point, so the undirected graph of the R-B colour grey-level feature is attained. Finally, regarding the undirected graph as the input of Ncut, we construct the weight matrix W by region points and determine the number of clusters based on the decision-theoretic rough set. The adaptive clustering segmentation can be implemented by an Ncut algorithm. Experimental results show that the maximum segmentation error is 3% and the average recognition time is less than 0.7s, which can meet the requirements of a real-time picking robot.

[The influence of IOL implantation on visual acuity, contrast sensitivity and colour vision 2 and 4 months after cataract surgery].

Science.gov (United States)

Ventruba, J

2006-04-01

To assess the change in visual acuity, contrast sensitivity and colour vision in relation to the time after cataract surgery and to the type of implanted IOL, and to compare visual functions by patients with one and two pseudophakic eyes. 45 cataract patients were examined before and then 2 and 4 month after the cataract surgery. Visual acuity (VA) was tested on logMAR optotype chart with Landolt rings, contrast sensitivity (CS) was tested on the Pelli-Robson chart and the SWCT chart. For colour vision (CV) testing, the standard Farnsworth D-15 test and the desaturated Lanthony D-15 test were used. The patients were divided into two groups--a group with one pseudophakic eye and a group with two pseudophakic eyes, and also according to the type of IOL--PMMA or hydrophobic acrylate that had been implanted. Control group was composed of phakic subjects with no ocular pathology. After the cataract surgery, in both groups there was a significant improvement in monocular and binocular VA (p test (p test (p tested by means of psychophysical methods of VA, CS and CV significantly improve and are stable 2 month after the surgery. The second eye surgery improves binocular visual functions the level of which doesn't differ from that of normal phakic subjects. There was no influence of the type of IOL on final state of VA, CS or CV.

Light Vision Color

Science.gov (United States)

Valberg, Arne

2005-04-01

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

Colour is more than hue: preferences for compiled colour traits in the stingless bees Melipona mondury and M. quadrifasciata.

Science.gov (United States)

Koethe, Sebastian; Bossems, Jessica; Dyer, Adrian G; Lunau, Klaus

2016-10-01

The colour vision of bees has been extensively analysed in honeybees and bumblebees, but few studies consider the visual perception of stingless bees (Meliponini). In a five-stage experiment the preference for colour intensity and purity, and the preference for the dominant wavelength were tested by presenting four colour stimuli in each test to freely flying experienced workers of two stingless bee species, Melipona mondury and Melipona quadrifasciata. The results with bee-blue, bee-UV-blue and bee-green colours offered in four combinations of varying colour intensity and purity suggest a complex interaction between these colour traits for the determination of colour choice. Specifically, M. mondury preferred bee-UV-blue colours over bee-green, bee-blue and bee-blue-green colours while M. quadrifasciata preferred bee-green colour stimuli. Moreover in M. mondury the preferences were different if the background colour was changed from grey to green. There was a significant difference between species where M. mondury preferred UV-reflecting over UV-absorbing bee-blue-green colour stimuli, whereas M. quadrifasciata showed an opposite preference. The different colour preferences of the free flying bees in identical conditions may be caused by the bees' experience with natural flowers precedent to the choice tests, suggesting reward partitioning between species.

Neural correlates of imagined and synaesthetic colours.

Science.gov (United States)

Rich, Anina N; Williams, Mark A; Puce, Aina; Syngeniotis, Ari; Howard, Matthew A; McGlone, Francis; Mattingley, Jason B

2006-01-01

The experience of colour is a core element of human vision. Colours provide important symbolic and contextual information not conveyed by form alone. Moreover, the experience of colour can arise without external stimulation. For many people, visual memories are rich with colour imagery. In the unusual phenomenon of grapheme-colour synaesthesia, achromatic forms such as letters, words and numbers elicit vivid experiences of colour. Few studies, however, have examined the neural correlates of such internally generated colour experiences. We used functional magnetic resonance imaging (fMRI) to compare patterns of cortical activity for the perception of external coloured stimuli and internally generated colours in a group of grapheme-colour synaesthetes and matched non-synaesthetic controls. In a voluntary colour imagery task, both synaesthetes and non-synaesthetes made colour judgements on objects presented as grey scale photographs. In a synaesthetic colour task, we presented letters that elicited synaesthetic colours, and asked participants to perform a localisation task. We assessed the neural activity underpinning these two different forms of colour experience that occur in the absence of chromatic sensory input. In both synaesthetes and non-synaesthetes, voluntary colour imagery activated the colour-selective area, V4, in the right hemisphere. In contrast, the synaesthetic colour task resulted in unique activity for synaesthetes in the left medial lingual gyrus, an area previously implicated in tasks involving colour knowledge. Our data suggest that internally generated colour experiences recruit brain regions specialised for colour perception, with striking differences between voluntary colour imagery and synaesthetically induced colours.

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..

Individualization of 2D color maps for people with color vision deficiencies

KAUST Repository

Waldin, Nicholas; Bernhard, Matthias; Rautek, Peter; Viola, Ivan

2016-01-01

2D color maps are often used to visually encode complex data characteristics such as heat or height. The comprehension of color maps in visualization is affected by the display (e.g., a monitor) and the perceptual abilities of the viewer. People with color vision deficiencies, such as red-green blindness, face difficulties when using conventional color maps. We propose a novel method for adapting a color map to an individual person, by having the user sort lines extracted from a given color map.

Individualization of 2D color maps for people with color vision deficiencies

KAUST Repository

Waldin, Nicholas

2016-12-13

2D color maps are often used to visually encode complex data characteristics such as heat or height. The comprehension of color maps in visualization is affected by the display (e.g., a monitor) and the perceptual abilities of the viewer. People with color vision deficiencies, such as red-green blindness, face difficulties when using conventional color maps. We propose a novel method for adapting a color map to an individual person, by having the user sort lines extracted from a given color map.

A treatable cause of myelopathy and vision loss mimicking neuromyelitis optica spectrum disorder: late-onset biotinidase deficiency.

Science.gov (United States)

Yilmaz, Sanem; Serin, Mine; Canda, Ebru; Eraslan, Cenk; Tekin, Hande; Ucar, Sema Kalkan; Gokben, Sarenur; Tekgul, Hasan; Serdaroglu, Gul

2017-06-01

Biotinidase deficiency is characterized by severe neurological manifestations as hypotonia, lethargy, ataxia, hearing loss, seizures and developmental retardation in its classical form. Late-onset biotinidase deficiency presents distinctly from the classical form such as limb weakness and vision problems. A 14-year-old boy presented with progressive vision loss and upper limb weakness. The patient was initiated steroid therapy with a preliminary diagnosis of neuromyelitis optica spectrum disorder due to the craniospinal imaging findings demonstrating optic nerve, brainstem and longitudinally extensive spinal cord involvement. Although the patient exhibited partial clinical improvement after pulse steroid therapy, craniocervical imaging performed one month after the initiation of steroid therapy did not show any regression. The CSF IgG index was <0.8 (normal: <0.8), oligoclonal band and aquaporin-4 antibodies were negative. Metabolic investigations revealed a low biotinidase enzyme activity 8% (0.58 nmoL/min/mL; normal range: 4.4 to 12). Genetic testing showed c.98-104delinsTCC and p.V457 M mutations in biotinidase (BTD) gene. At the third month of biotin replacement therapy, control craniospinal MRI demonstrated a complete regression of the lesions. The muscle strength of the case returned to normal. His visual acuity was 7/10 in the left eye and 9/10 in the right. The late-onset form of the biotinidase deficiency should be kept in mind in all patients with myelopathy with or without vision loss, particularly in those with inadequate response to steroid therapy. The family screening is important to identify asymptomatic individuals and timely treatment.

Colour Perception in Ancient World

Science.gov (United States)

Nesterov, D. I.; Fedorova, M. Yu

2017-11-01

How did the human thought form the surrounding color information into the persistent semantic images of a mythological, pseudoscientific and religious nature? The concepts associated with colour perception are suggested. The existence of colour environment does not depend on the human consciousness. The colour culture formation is directly related to the level of the human consciousness development and the possibility to influence the worldview and culture. The colour perception of a person goes through the stages similar to the development of colour vision in a child. Like any development, the colour consciousness has undergone stages of growth and decline, evolution and stagnation. The way of life and difficult conditions for existence made their own adjustments to the development of the human perception of the surrounding world. Wars have been both a powerful engine of progress in all spheres of life and a great destructive force demolishing the already created and preserved heritage. The surrounding world has always been interesting for humans, evoked images and fantasies in the consciousness of ancient people. Unusual and inexplicable natural phenomena spawned numerous legends and myths which was reflected in the ancient art and architecture and, accordingly, in a certain manifestation of colour in the human society. The colour perception of the ancient man, his pragmatic, utilitarian attitude to colour is considered as well as the influence of dependence on external conditions of existence and their reflection in the colour culture of antiquity. “Natural Science” conducts research in the field of the colour nature and their authorial interpretation of the Hellenic period. Several authorial concepts of the ancient world have been considered.

Colour application on mammography image segmentation

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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%).

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.

Characterisation of flotation froth colour and structure by machine vision

Science.gov (United States)

Bonifazi, Giuseppe; Serranti, Silvia; Volpe, Fabio; Zuco, Riccardo

2001-11-01

It is well known and well recognised that flotation is a process that is complex to monitor and study if a classical approach based on the evaluation of the signals resulting from sensors is adopted. Sensors are usually strategically positioned in the bank cells and detect global process variables such as pH, reagent addition, froth level, on-stream chemical analysis, particle size distribution, etc. In the last ten years several studies have been carried out with the main goal to utilise imaging techniques to detect froth bubbles characteristics and to evaluate the flotation process performance. In this paper an approach of this type is described. More specifically, image processing techniques to automatically measure the colour and the structure of the froth bubbles are presented and the results are discussed. All the investigations are carried out on digital sample images collected in an industrial flotation plant operating in steady-state conditions. The colour analysis is performed on the whole surface of the froth images considering different colour reference systems (RGB, HSV, HSI); the morphological measurements are obtained after the application of selected enhancement and segmentation techniques, necessary to consider the bubbles as separate domains. The multiple correlation analysis performed between froth mineral concentrations (Cu, MgO, Zn and Pb content) and the extracted colour and structure parameters are good in most situations.

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; Kelber, Almut; Donner, Kristian

2017-04-05

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'. © 2017 The Authors.

Adaptive Colour Feature Identification in Image for Object Tracking

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Feng Su

2012-01-01

Full Text Available Identification and tracking of a moving object using computer vision techniques is important in robotic surveillance. In this paper, an adaptive colour filtering method is introduced for identifying and tracking a moving object appearing in image sequences. This filter is capable of automatically identifying the most salient colour feature of the moving object in the image and using this for a robot to track the object. The method enables the selected colour feature to adapt to surrounding condition when it is changed. A method of determining the region of interest of the moving target is also developed for the adaptive colour filter to extract colour information. Experimental results show that by using a camera mounted on a robot, the proposed methods can perform robustly in tracking a randomly moving object using adaptively selected colour features in a crowded environment.

Low Vision Devices and Training

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Imran Azam Butt

2004-01-01

Full Text Available Vision is the ability to see with a clear perception of detail, colour and contrast, and to distinguish objects visually. Like any other sense, vision tends to deteriorate or diminish naturally with age. In most cases, reduction in visual capability can be corrected with glasses, medicine or surgery. However, if the visual changes occur because of an incurable eye disease, condition or injury, vision loss can be permanent. Many people around the world with permanent visual impairment have some residual vision which can be used with the help of low vision services, materials and devices. This paper describes different options for the enhancement of residual vision including optical and non-optical devices and providing training for the low vision client.

Color vision: introduction by the feature editors.

Science.gov (United States)

Buck, Steven L; Baraas, Rigmor; Lee, Barry B; Lindsey, Delwin T; Uchikawa, Keiji; Webster, Michael A; Werner, John S

2016-03-01

This feature issue of the Journal of the Optical Society of America A (JOSA A) reflects the basic and applied research interests of members of the color vision community. Most of the articles stem from presentations at the 23rd Biennial Symposium of the International Colour Vision Society (ICVS).

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.

Colour centres in germanosilicate glass and optical fibres

International Nuclear Information System (INIS)

Neustruev, V.B.

1994-01-01

This review presents the state of the art of the study of germanium-related colour centres in silica glass and silica-based fibres. Most attention is concentrated on the dominant colour centres such as the Ge-related oxygen-deficient centres and paramagnetic Ge(n) centres, all of them having ultraviolet absorption bands. The hypothetical models and formation mechanisms proposed so far for these colour centres are discussed in detail. The origins of the models and formation mechanisms and their weak and strong points are analysed. The origin of the less well studied Ge-related colour centres in the visible spectral range (GeH, GeX, drawing-dependent defects) is also discussed. (author)

Color Vision 2018: Introduction by the feature editors.

Science.gov (United States)

Buck, Steven L; Baraas, Rigmor; Kremers, Jan; Lindsey, Delwin T; Nascimento, Sérgio M C; Webster, Michael A; Werner, John S

2018-04-01

This feature issue of the Journal of the Optical Society of America A (JOSA A) reflects the basic and applied research interests of members of the color vision community. Most of the articles stem from presentations at the 24th Biennial Symposium of the International Colour Vision Society (ICVS).

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.

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...

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

Directory of Open Access Journals (Sweden)

Laxmi Gella

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

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

Mapping the timecourse of goal-directed attention to location and colour in human vision.

Science.gov (United States)

Adams, Rachel C; Chambers, Christopher D

2012-03-01

Goal-directed attention prioritises perception of task-relevant stimuli according to location, features, or onset time. In this study we compared the behavioural timecourse of goal-directed selection to locations and colours by varying the stimulus-onset asynchrony (SOA) between cue and target in a strategic cueing paradigm. Participants reported the presence or absence of a target following prior information regarding its location or colour. Results revealed that preparatory selection by colour is more effective at enhancing perceptual sensitivity than selection by location, even though both types of cue provided equivalent overall information. More detailed analysis revealed that this advantage arose due a limitation of spatial attention in maintaining a sufficiently broad focus (>2°) for target detection across multiple stimuli. In contrast, when target stimuli fell within 2° of the spatial attention spotlight, the strategic advantages and speed of spatial and colour attention were equated. Our findings are consistent with the conclusion that, under spatially optimal conditions, prior spatial and colour information are equally proficient at guiding top-down selection. When spatial locations are ambiguous, however, colour-based selection is the more efficient mechanism. Copyright © 2012 Elsevier B.V. All rights reserved.

SPECTRAL AND SPATIAL SELECTIVITY OF LUMINANCE VISION IN REEF FISH

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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.

Multispectral analysis and cone signal modelling of pseudoisochromatic test plates

International Nuclear Information System (INIS)

Luse, K; Ozolinsh, M; Gutmane, A; Fomins, S

2013-01-01

The aim of the study is to determine the consistency of the desired colour reproduction of the stimuli using calibrated printing technology available to anyone (EpsonStylus Pro 7800 printer was). 24 colour vision assessment plates created in the University of Latvia were analysed right after their fabrication on august 2012 and after intense use for 7 months (colour vision screening on 700 people). Multispectral imagery results indicate that the alignment of the samples after seven months of use has maintained on the CIExy confusion lines of deutan deficiency type, but the shift towards achromatic area in the diagram indicate decrease in the total colour difference (ΔE* ab ) of test background (achromatic) areas and stimuli (chromatic) areas, thus affecting the testing outcome and deficiency severity level classification ability of the plates

Colour preferences of UK garden birds at supplementary seed feeders.

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Luke Rothery

Full Text Available 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.

Rockpool gobies change colour for camouflage.

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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.

Rockpool gobies change colour for camouflage.

Science.gov (United States)

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

2014-01-01

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

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

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.

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

OpenAIRE

MUTLU Mehmet Mete; ORK Nilay; YAKUT Fatih

2017-01-01

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 p...

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.

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.

Effects of memory colour on colour constancy for unknown coloured objects.

Science.gov (United States)

Granzier, Jeroen J M; Gegenfurtner, Karl R

2012-01-01

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.

Accessible maps for the color vision deficient observers: past and present knowledge and future possibilities

Science.gov (United States)

Kvitle, Anne Kristin

2018-05-01

Color is part of the visual variables in map, serving an aesthetic part and as a guide of attention. Impaired color vision affects the ability to distinguish colors, which makes the task of decoding the map colors difficult. Map reading is reported as a challenging task for these observers, especially when the size of stimuli is small. The aim of this study is to review existing methods for map design for color vision deficient users. A systematic review of research literature and case studies of map design for CVD observers has been conducted in order to give an overview of current knowledge and future research challenges. In addition, relevant research on simulations of CVD and color image enhancement for these observers from other fields of industry is included. The study identified two main approaches: pre-processing by using accessible colors and post-processing by using enhancement methods. Some of the methods may be applied for maps, but requires tailoring of test images according to map types.

Color Vision Changes and Effects of High Contrast Visor Use at Simulated Cabin Altitudes

Science.gov (United States)

2016-06-08

Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person...Morris DS, Kalson NS, Wright AD, Imray CHE, et al. Changes to colour vision on exposure to high altitude. J R Army Med Corps. 2011; 157(1):107-109...4. Richalet JP, Duval-Arnould G, Darnaud B, Keromes A, Rutgers V. Modification of colour vision in the green/red axis in acute and chronic

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.

Effects of memory colour on colour constancy for unknown coloured objects

OpenAIRE

Granzier, Jeroen J M; Gegenfurtner, Karl R

2012-01-01

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...

Cone photoreceptor structure in patients with x-linked cone dysfunction and red-green color vision deficiency

DEFF Research Database (Denmark)

Patterson, Emily J.; Wilk, Melissa; Langlo, Christopher S.

2016-01-01

encoded by exon 4, and two with a novel insertion in exon 2. Foveal cone structure and retinal thickness was disrupted to a variable degree, even among related individuals with the same L/M array. CONCLUSIONS. Our findings provide a direct link between disruption of the cone mosaic and L/ M opsin variants......PURPOSE. Mutations in the coding sequence of the L and M opsin genes are often associated with X-linked cone dysfunction (such as Bornholm Eye Disease, BED), though the exact color vision phenotype associated with these disorders is variable. We examined individuals with L/ M opsin gene mutations...... to clarify the link between color vision deficiency and cone dysfunction.  METHODS. We recruited 17 males for imaging. The thickness and integrity of the photoreceptor layers were evaluated using spectral-domain optical coherence tomography. Cone density was measured using high-resolution images of the cone...

Hypoxia, color vision deficiencies, and blood oxygen saturation.

Science.gov (United States)

2013-11-01

Chromatic thresholds were measured using the Cambridge Color Test (CCT), Color Assessment and Diagnosis : (CAD) test, and Cone Specific Contrast Test at ground and 3780 m (12,400 ft) for subjects with normal color : vision and red-green color vision ...

Colour based fire detection method with temporal intensity variation filtration

International Nuclear Information System (INIS)

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

2015-01-01

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

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.

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

Science.gov (United States)

Horridge, Adrian

2015-01-01

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

Evolution of ultraviolet vision in the largest avian radiation - the passerines.

Science.gov (United States)

Ödeen, Anders; Håstad, Olle; Alström, Per

2011-10-24

Interspecific variation in avian colour vision falls into two discrete classes: violet sensitive (VS) and ultraviolet sensitive (UVS). They are characterised by the spectral sensitivity of the most shortwave sensitive of the four single cones, the SWS1, which is seemingly under direct control of as little as one amino acid substitution in the cone opsin protein. Changes in spectral sensitivity of the SWS1 are ecologically important, as they affect the abilities of birds to accurately assess potential mates, find food and minimise visibility of social signals to predators. Still, available data have indicated that shifts between classes are rare, with only four to five independent acquisitions of UV sensitivity in avian evolution. We have classified a large sample of passeriform species as VS or UVS from genomic DNA and mapped the evolution of this character on a passerine phylogeny inferred from published molecular sequence data. Sequencing a small gene fragment has allowed us to trace the trait changing from one stable state to another through the radiation of the passeriform birds. Their ancestor is hypothesised to be UVS. In the subsequent radiation, colour vision changed between UVS and VS at least eight times. The phylogenetic distribution of SWS1 cone opsin types in Passeriformes reveals a much higher degree of complexity in avian colour vision evolution than what was previously indicated from the limited data available. Clades with variation in the colour vision system are nested among clades with a seemingly stable VS or UVS state, providing a rare opportunity to understand how an ecologically important trait under simple genetic control may co-evolve with, and be stabilised by, associated traits in a character complex.

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.

Can the Farnsworth D15 Color Vision Test Be Defeated through Practice?

Science.gov (United States)

Ng, Jason S; Liem, Sophia C

2018-05-01

This study suggests that it is possible for some patients with severe red-green color vision deficiency to do perfectly on the Farnsworth D15 test after practicing it. The Farnsworth D15 is a commonly used test to qualify people for certain occupations. For patients with color vision deficiency, there may be high motivation to try to pass the test through practice to gain entry into a particular occupation. There is no evidence in the literature on whether it is possible for patients to learn to pass the D15 test through practice. Ten subjects with inherited red-green color vision deficiency and 15 color-normal subjects enrolled in the study. All subjects had anomaloscope testing, color vision book tests, and a Farnsworth D15 at an initial visit. For the D15, the number of major crossovers was determined for each subject. Failing the D15 was determined as greater than 1 major crossover. Subjects with color vision deficiency practiced the D15 as long as desired to achieve a perfect score and then returned for a second visit for D15 testing. A paired t test was used to analyze the number of major crossovers at visit 1 versus visit 2. Color-normal subjects did not have any major crossovers. Subjects with color vision deficiency had significantly (P color vision deficiency, and this should be considered in certain cases where occupational entry is dependent on D15 testing.

Visual awareness of objects and their colour.

Science.gov (United States)

Pilling, Michael; Gellatly, Angus

2011-10-01

At any given moment, our awareness of what we 'see' before us seems to be rather limited. If, for instance, a display containing multiple objects is shown (red or green disks), when one object is suddenly covered at random, observers are often little better than chance in reporting about its colour (Wolfe, Reinecke, & Brawn, Visual Cognition, 14, 749-780, 2006). We tested whether, when object attributes (such as colour) are unknown, observers still retain any knowledge of the presence of that object at a display location. Experiments 1-3 involved a task requiring two-alternative (yes/no) responses about the presence or absence of a colour-defined object at a probed location. On this task, if participants knew about the presence of an object at a location, responses indicated that they also knew about its colour. A fourth experiment presented the same displays but required a three-alternative response. This task did result in a data pattern consistent with participants' knowing more about the locations of objects within a display than about their individual colours. However, this location advantage, while highly significant, was rather small in magnitude. Results are compared with those of Huang (Journal of Vision, 10(10, Art. 24), 1-17, 2010), who also reported an advantage for object locations, but under quite different task conditions.

Screening for Congenital Color Vision Deficiency in Primary ...

African Journals Online (AJOL)

Methods: The teachers were randomly selected from 13 schools in Port Harcourt City (PHC) and given a six hours training workshop on vision disorders in children and congenital color vision screening. They were given a self administered pre and post test questionnaires before and after training respectively. Subsequently ...

Evaluation of functional color vision requirements and current color vision screening tests for air traffic control specialists.

Science.gov (United States)

1990-08-01

An experiment was conducted to evaluate the relation of type and degree of color vision deficiency and aeromedical color vision screening test scores to performance of color-dependent tasks of Air Traffic Control Specialists. The subjects included 37...

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.

Innate colour preferences of the Australian native stingless bee Tetragonula carbonaria Sm.

Science.gov (United States)

Dyer, Adrian G; Boyd-Gerny, Skye; Shrestha, Mani; Lunau, Klaus; Garcia, Jair E; Koethe, Sebastian; Wong, Bob B M

2016-10-01

Innate preferences promote the capacity of pollinators to find flowers. Honeybees and bumblebees have strong preferences for 'blue' stimuli, and flowers of this colour typically present higher nectar rewards. Interestingly, flowers from multiple different locations around the world independently have the same distribution in bee colour space. Currently, however, there is a paucity of data on the innate colour preferences of stingless bees that are often implicated as being key pollinators in many parts of the world. In Australia, the endemic stingless bee Tetragonula carbonaria is widely distributed and known to be an efficient pollinator of both native plants and agricultural crops. In controlled laboratory conditions, we tested the innate colour responses of naïve bees using standard broadband reflectance stimuli representative of common flower colours. Colorimetric analyses considering hymenopteran vision and a hexagon colour space revealed a difference between test colonies, and a significant effect of green contrast and an interaction effect of green contrast with spectral purity on bee choices. We also observed colour preferences for stimuli from the blue and blue-green categorical regions of colour space. Our results are discussed in relation to the similar distribution of flower colours observed from bee pollination around the world.

Evolution of ultraviolet vision in the largest avian radiation - the passerines

Directory of Open Access Journals (Sweden)

Håstad Olle

2011-10-01

Full Text Available Abstract Background Interspecific variation in avian colour vision falls into two discrete classes: violet sensitive (VS and ultraviolet sensitive (UVS. They are characterised by the spectral sensitivity of the most shortwave sensitive of the four single cones, the SWS1, which is seemingly under direct control of as little as one amino acid substitution in the cone opsin protein. Changes in spectral sensitivity of the SWS1 are ecologically important, as they affect the abilities of birds to accurately assess potential mates, find food and minimise visibility of social signals to predators. Still, available data have indicated that shifts between classes are rare, with only four to five independent acquisitions of UV sensitivity in avian evolution. Results We have classified a large sample of passeriform species as VS or UVS from genomic DNA and mapped the evolution of this character on a passerine phylogeny inferred from published molecular sequence data. Sequencing a small gene fragment has allowed us to trace the trait changing from one stable state to another through the radiation of the passeriform birds. Their ancestor is hypothesised to be UVS. In the subsequent radiation, colour vision changed between UVS and VS at least eight times. Conclusions The phylogenetic distribution of SWS1 cone opsin types in Passeriformes reveals a much higher degree of complexity in avian colour vision evolution than what was previously indicated from the limited data available. Clades with variation in the colour vision system are nested among clades with a seemingly stable VS or UVS state, providing a rare opportunity to understand how an ecologically important trait under simple genetic control may co-evolve with, and be stabilised by, associated traits in a character complex.

A Call for Considering Color Vision Deficiency When Creating Graphics for Psychology Reports.

Science.gov (United States)

Frane, Andrew

2015-01-01

Although color vision deficiency (CVD) is fairly common, it is often not adequately considered when data is presented in color graphics. This study found that CVD tends to be mentioned neither in the author guidelines of psychology journals nor in the standard publication manuals of the field (e.g., the publication manuals of the American Psychological Association and the American Medical Association). To illustrate the relevance of this problem, a panel of scholars with CVD was used to evaluate the color figures in three respected psychological science journals. Results suggested that a substantial proportion of those figures were needlessly confusing for viewers with CVD and could have been easily improved through simple adjustments. Based on prior literature and on feedback from the panelists, recommendations are made for improving the accessibility of graphics in psychology reports.

Effect of absence of vision on posture

OpenAIRE

Alotaibi, Abdullah Z.; Alghadir, Ahmad; Iqbal, Zaheen A.; Anwer, Shahnawaz

2016-01-01

[Purpose] The visual system is one of the sensory systems that enables the body to assess and process information about the external environment. In the absence of vision, a blind person loses contact with the outside world and develops faulty motor patterns, which results in postural deficiencies. However, literature regarding the development of such deficiencies is limited. The aim of this study was to discuss the effect of absence of vision on posture, the possible biomechanics behind the ...

Processing bimodal stimuli: Integrality/separability of colour and orientation

Directory of Open Access Journals (Sweden)

David eBimler

2013-10-01

Full Text Available We examined how two distinct stimulus features, orientation and colour, interact as contributions to global stimulus dissimilarity. Five subjects rated dissimilarity between pairs of bars (N = 30 varying in colour (four cardinal hues, plus white and orientation (six angles at 30° intervals. An exploratory analysis with individual-differences multidimensional scaling resulted in a 5D solution, with two dimensions required to accommodate the circular sequence of the angular attribute, and red-green, blue-yellow and achromatic axes for the colour attribute. Weights of the orientation subspace relative to the colour subspace varied among the subjects, from a 0.32:0.61 ratio to 0.53:0.44, emphasis shifting between colour and orientation. In addition to Euclidean metric, we modelled the interaction of colour and orientation using Minkowski power metrics across a range of Minkowski exponents p, including the city-block (p = 1, Euclidean (p = 2 and Dominance metric (p à ¥ as special cases. For averaged data, p ~ 1.3 provided the best fit, i.e. intermediate between separable and integral features. For individual subjects, however, the metric exponent varied significantly from p = 0.7 to p = 3.1, indicating a subject-specific rule for combining colour and orientation, as in Tversky and Gati’s variable-weights model. No relationship was apparent between dimensional weights and individual p exponents. Factors affecting dimensional integrality are discussed, including possible underlying neural mechanisms where the interaction of the low-level vision attributes orientation and colour might shift between uncorrelated (p =1 or correlated (p ³ 2 forms.

Human lens colouration, age and cataract

International Nuclear Information System (INIS)

Truscott, R.J.W.; Garner, B.; Hood, B.

1999-01-01

Full text: The human lens biosynthesises UV filter compounds which effectively remove light in the 300-400nm band. These chemicals are present either as an aid to visual acuity, or to filter out damaging UV radiation. The primate UV filters are 3-hydroxykynurenine analogues derived from the metabolism of tryptophan. We have recently demonstrated that these endogenous UV filters are not innocuous, but are in fact capable of binding to proteins, including the crystalline proteins which make up the bulk of the lens. Thus, over time, the levels of protein - bound UV filters increase and this results in the human lens becoming progressively more yellow as we age. This colouration affects our colour vision and it may also be responsible for the brown colour of lenses which is the hallmark of age-related nuclear cataract. An understanding of the intrinsic instability of the endogenous UV filters, combined with changes in the internal transport of these and other small molecular weight compounds including antioxidants, such as glutathione, is allowing us to gain an insight into the processes responsible for the development of age-related cataract: the major cause of world blindness

A Vision-Based Approach to Fire Detection

Directory of Open Access Journals (Sweden)

Pedro Gomes

2014-09-01

Full Text Available This paper presents a vision-based method for fire detection from fixed surveillance smart cameras. The method integrates several well-known techniques properly adapted to cope with the challenges related to the actual deployment of the vision system. Concretely, background subtraction is performed with a context-based learning mechanism so as to attain higher accuracy and robustness. The computational cost of a frequency analysis of potential fire regions is reduced by means of focusing its operation with an attentive mechanism. For fast discrimination between fire regions and fire-coloured moving objects, a new colour-based model of fire's appearance and a new wavelet-based model of fire's frequency signature are proposed. To reduce the false alarm rate due to the presence of fire-coloured moving objects, the category and behaviour of each moving object is taken into account in the decision-making. To estimate the expected object's size in the image plane and to generate geo-referenced alarms, the camera-world mapping is approximated with a GPS-based calibration process. Experimental results demonstrate the ability of the proposed method to detect fires with an average success rate of 93.1% at a processing rate of 10 Hz, which is often sufficient for real-life applications.

Color Vision Defects in School Going Children

Directory of Open Access Journals (Sweden)

R K Shrestha

2010-12-01

Full Text Available Introduction: Color Vision defect can be observed in various diseases of optic nerve and retina and also a significant number of people suffer from the inherited condition of red and green color defect. Methods: A cross-sectional descritptive study was designed with purposive sampling of students from various schools of Kathmandu Valley. All children were subjected to color vision evaluation using Ishihara Isochromatic color plates along with other examination to rule out any other causes of color deficiency. Results: A total of 2001 students were examined, 1050 male students and 951 females with mean age of 10.35 (±2.75 and 10.54 (±2.72 respectively. Among the total students examined, 2.1% had some form of color vision defects. Of the male population , 3.9% had color vision defects while none of the female was found with the deficiency. Conclusions: The prelevance of color vision defect in Nepal is significant and comparable with the prelevance quoted in the studies from different countries. Keywords:color vision; congenital red green color effect; Nepal; prevalence.

Effect of absence of vision on posture.

Science.gov (United States)

Alotaibi, Abdullah Z; Alghadir, Ahmad; Iqbal, Zaheen A; Anwer, Shahnawaz

2016-04-01

[Purpose] The visual system is one of the sensory systems that enables the body to assess and process information about the external environment. In the absence of vision, a blind person loses contact with the outside world and develops faulty motor patterns, which results in postural deficiencies. However, literature regarding the development of such deficiencies is limited. The aim of this study was to discuss the effect of absence of vision on posture, the possible biomechanics behind the resulting postural deficiencies, and strategies to correct and prevent them. [Subjects and Methods] Various electronic databases including PubMed, Medline, and Google scholar were examined using the words "body", "posture", "blind" and "absence of vision". References in the retrieved articles were also examined for cross-references. The search was limited to articles in the English language. [Results] A total of 74 papers were shortlisted for this review, most of which dated back to the 1950s and 60s. [Conclusion] Blind people exhibit consistent musculoskeletal deformities. Absence of vision leads to numerous abnormal sensory and motor interactions that often limit blind people in isolation. Rehabilitation of the blind is a multidisciplinary task. Specialists from different fields need to diagnose and treat the deficiencies of the blind together as a team. Before restoring the normal mechanics of posture and gait, the missing link with the external world should be reestablished.

Color Vision in Aniridia.

Science.gov (United States)

Pedersen, Hilde R; Hagen, Lene A; Landsend, Erlend C S; Gilson, Stuart J; Utheim, Øygunn A; Utheim, Tor P; Neitz, Maureen; Baraas, Rigmor C

2018-04-01

To assess color vision and its association with retinal structure in persons with congenital aniridia. We included 36 persons with congenital aniridia (10-66 years), and 52 healthy, normal trichromatic controls (10-74 years) in the study. Color vision was assessed with Hardy-Rand-Rittler (HRR) pseudo-isochromatic plates (4th ed., 2002); Cambridge Color Test and a low-vision version of the Color Assessment and Diagnosis test (CAD-LV). Cone-opsin genes were analyzed to confirm normal versus congenital color vision deficiencies. Visual acuity and ocular media opacities were assessed. The central 30° of both eyes were imaged with the Heidelberg Spectralis OCT2 to grade the severity of foveal hypoplasia (FH, normal to complete: 0-4). Five participants with aniridia had cone opsin genes conferring deutan color vision deficiency and were excluded from further analysis. Of the 31 with aniridia and normal opsin genes, 11 made two or more red-green (RG) errors on HRR, four of whom also made yellow-blue (YB) errors; one made YB errors only. A total of 19 participants had higher CAD-LV RG thresholds, of which eight also had higher CAD-LV YB thresholds, than normal controls. In aniridia, the thresholds were higher along the RG than the YB axis, and those with a complete FH had significantly higher RG thresholds than those with mild FH (P = 0.038). Additional increase in YB threshold was associated with secondary ocular pathology. Arrested foveal formation and associated alterations in retinal processing are likely to be the primary reason for impaired red-green color vision in aniridia.

Background colour matching by a crab spider in the field: a community sensory ecology perspective.

Science.gov (United States)

Defrize, Jérémy; Théry, Marc; Casas, Jérôme

2010-05-01

The question of whether a species matches the colour of its natural background in the perspective of the correct receiver is complex to address for several reasons; however, the answer to this question may provide invaluable support for functional interpretations of colour. In most cases, little is known about the identity and visual sensory abilities of the correct receiver and the precise location at which interactions take place in the field, in particular for mimetic systems. In this study, we focused on Misumena vatia, a crab spider meeting the criteria for assessing crypsis better than many other models, and claimed to use colour changes for both aggressive and protective crypsis. We carried out a systematic field survey to quantitatively assess the exactness of background colour matching in M. vatia with respect to the visual system of many of its receivers within the community. We applied physiological models of bird, bee and blowfly colour vision, using flower and spider spectral reflectances measured with a spectroradiometer. We observed that crypsis at long distance is systematically achieved, exclusively through achromatic contrast, in both bee and bird visions. At short distance, M. vatia is mostly chromatically detectable, whatever the substrate, for bees and birds. However, spiders can be either poorly discriminable or quite visible depending on the substrate for bees. Spiders are always chromatically undetectable for blowflies. We discuss the biological relevance of these results in both defensive and aggressive contexts of crypsis within a community sensory perspective.

High-speed Fourier transform profilometry for reconstructing objects having arbitrary surface colours

International Nuclear Information System (INIS)

Chen, Liang-Chia; Nguyen, Xuan Loc; Zhang, Fu-Hao; Lin, Tzeng-Yow

2010-01-01

In this paper, Fourier transform profilometry (FTP) using a colour fringe selection technique for accurate phase map reconstruction is newly proposed to overcome the limitation of FTP in measuring objects having arbitrary surface colours. The sinusoidal colour fringe pattern is encoded to form a unique colour pattern for projecting onto the object's surface, and its reflected deformed fringe image is taken using a triple-colour CCD camera and rapidly processed by the developed FTP method employing a novel band-pass filter. A new 3D vision system is capable of measuring objects with a high speed of up to 60 frames s −1 . To reconstruct the 3D profile of an object having arbitrary surface colours, an innovative strategy is developed to identify the colour channel of the detected fringe pattern with the best modulation transfer function (MTF) for retrieving accurate phase maps. The experimental results demonstrate that the system has the capability to acquire 3D maps at a high speed while the measurement accuracy of the developed method is substantially better than that of the traditional FTP method. By measuring the standard step heights in a repeatability test, it is confirmed that a maximum measured error can be controlled to less than 2.8% of the overall measuring depth range

Ultrasonographic elastography of thyroid nodules: Is adding strain ratio to colour mapping better?

International Nuclear Information System (INIS)

Chong, Y.; Shin, J.H.; Ko, E.S.; Han, B.-K.

2013-01-01

Aim: To determine the diagnostic performance of colour mapping and strain ratio for characterizing malignant thyroid nodules on ultrasonographic (US) elastography. Materials and methods: The study was approved by the institutional review board and written informed consent was obtained. One hundred and thirty-one patients with 142 thyroid nodules >0.5 cm were prospectively enrolled between July 2010 and January 2011. Seven radiologists performed US elastography (iU22 Vision 2010; Philips, Seattle, WA, USA) using colour mapping and strain ratio for thyroid nodules blinded to the cytopathological results. Diagnostic performances of colour mapping alone, strain ratio alone, colour mapping and strain ratio, and colour mapping or strain ratio were compared using receiver operating characteristic (ROC) curve analysis. Results: Of the 142 nodules, 69 (48.6%) were benign and 73 (51.4%) were malignant. Colour mapping of elastography showed a more frequent blue colour in malignant nodules than in benign nodules (65.8% versus 24.6%, p < 0.0001). A higher ratio than 1.21 as the best cut-off value was found in 65.8% of malignant nodules and 46.4% of benign nodules (p = 0.030). Area under the ROC curve (AUC) of colour mapping alone was significantly greater than that of colour mapping or strain ratio (AUC = 0.706 versus AUC = 0.63, p = 0.0195) and similar to that of colour mapping and strain ratio (AUC = 0.673, p = 0.1364). Conclusion: US elastography is helpful to predict malignant thyroid nodules. However, adding strain ratio to colour mapping does not improve performance compared to colour mapping alone

Flower colour and cytochromes P450.

Science.gov (United States)

Tanaka, Yoshikazu; Brugliera, Filippa

2013-02-19

Cytochromes P450 play important roles in biosynthesis of flavonoids and their coloured class of compounds, anthocyanins, both of which are major floral pigments. The number of hydroxyl groups on the B-ring of anthocyanidins (the chromophores and precursors of anthocyanins) impact the anthocyanin colour, the more the bluer. The hydroxylation pattern is determined by two cytochromes P450, flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) and thus they play a crucial role in the determination of flower colour. F3'H and F3'5'H mostly belong to CYP75B and CYP75A, respectively, except for the F3'5'Hs in Compositae that were derived from gene duplication of CYP75B and neofunctionalization. Roses and carnations lack blue/violet flower colours owing to the deficiency of F3'5'H and therefore lack the B-ring-trihydroxylated anthocyanins based upon delphinidin. Successful redirection of the anthocyanin biosynthesis pathway to delphinidin was achieved by expressing F3'5'H coding regions resulting in carnations and roses with novel blue hues that have been commercialized. Suppression of F3'5'H and F3'H in delphinidin-producing plants reduced the number of hydroxyl groups on the anthocyanidin B-ring resulting in the production of monohydroxylated anthocyanins based on pelargonidin with a shift in flower colour to orange/red. Pelargonidin biosynthesis is enhanced by additional expression of a dihydroflavonol 4-reductase that can use the monohydroxylated dihydrokaempferol (the pelargonidin precursor). Flavone synthase II (FNSII)-catalysing flavone biosynthesis from flavanones is also a P450 (CYP93B) and contributes to flower colour, because flavones act as co-pigments to anthocyanins and can cause blueing and darkening of colour. However, transgenic plants expression of a FNSII gene yielded paler flowers owing to a reduction of anthocyanins because flavanones are precursors of anthocyanins and flavones.

Wing scale ultrastructure underlying convergent and divergent iridescent colours in mimetic Heliconius butterflies.

Science.gov (United States)

Parnell, Andrew J; Bradford, James E; Curran, Emma V; Washington, Adam L; Adams, Gracie; Brien, Melanie N; Burg, Stephanie L; Morochz, Carlos; Fairclough, J Patrick A; Vukusic, Pete; Martin, Simon J; Doak, Scott; Nadeau, Nicola J

2018-04-01

Iridescence is an optical phenomenon whereby colour changes with the illumination and viewing angle. It can be produced by thin film interference or diffraction. Iridescent optical structures are fairly common in nature, but relatively little is known about their production or evolution. Here we describe the structures responsible for producing blue-green iridescent colour in Heliconius butterflies. Overall the wing scale structures of iridescent and non-iridescent Heliconius species are very similar, both having longitudinal ridges joined by cross-ribs. However, iridescent scales have ridges composed of layered lamellae, which act as multilayer reflectors. Differences in brightness between species can be explained by the extent of overlap of the lamellae and their curvature as well as the density of ridges on the scale. Heliconius are well known for their Müllerian mimicry. We find that iridescent structural colour is not closely matched between co-mimetic species. Differences appear less pronounced in models of Heliconius vision than models of avian vision, suggesting that they are not driven by selection to avoid heterospecific courtship by co-mimics. Ridge profiles appear to evolve relatively slowly, being similar between closely related taxa, while ridge density evolves faster and is similar between distantly related co-mimics. © 2018 The Authors.

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...

Hypoxia, Color Vision Deficiencies, and Blood Oxygen Saturation

Science.gov (United States)

2013-11-01

using the Dvorine Pseudoisochromatic Plate Test (2nd edition, Psychological Corporation, Baltimore, MD) illuminated by True Daylight Illuminator T8...Plant, G.T. (1994). Insights into the different exploits of colour in the visual cortex. Proc Biol Sci, 258 (1353), 327-334. Barbur, J.L...Aviat Space Environ Med, 80, 933-940. Crow, T.J.,& Kelman, G.R.(1973). Psychological effects of mild acute hypoxia. Br J Anaesth, 45, 335-337

Iron-Deficiency Anemia

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Full Text Available ... and Strategic Vision Leadership Scientific Divisions Operations and Administration Advisory Committees Budget and Legislative Information Jobs and ... may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia. ...

Iron-Deficiency Anemia

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Full Text Available ... and Strategic Vision Leadership Scientific Divisions Operations and Administration Advisory Committees Budget and Legislative Information Jobs and ... blood cells. Iron-deficiency anemia usually develops over time because your body’s intake of iron is too ...

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.

Colour in flux: describing and printing colour in art

Science.gov (United States)

Parraman, Carinna

2008-01-01

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

Poor vision, refractive errors and barriers to treatment among ...

African Journals Online (AJOL)

Poor vision, refractive errors and barriers to treatment among commercial vehicle drivers in the Cape Coast municipality. ... were also administered to the participants to collect demographic data, history of driving and RTAs and utilization of eye care services as well as identification of the colours of the traffic light. Results: A ...

Colour simplicity

OpenAIRE

du Preez, Warren

2017-01-01

This dissertation addresses the metaphysics of conscious experience. I defend a thesis labelled Colour Simplicity, according to which the properties constitutive of what it is like to have visual sensory experiences of colour – colour qualia – are simple, in that they lack more basic constituent properties. I develop a valid argument for Colour Simplicity, drawing on the premises that (P1) ‘colour qualia appear to be simple under introspection’, and (P2) ‘if colour qualia appear to be simp...

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.

Daylight Influence on Colour Design : Empirical Study on Perceived Colour and Colour Experience Indoors

OpenAIRE

Hårleman, Maud

2007-01-01

It is known that one and the same interior colouring will appear different in rooms with windows facing north or facing south, but it is not known how natural daylight from these two compass points affects perceived colour and the ways in which colour is experienced. The objective is to describe the perceived colours to be expected in rooms with sunlight and diffused light, and thus develop a tool for colour design. Two empirical investigations provide the basis for six attached papers. The m...

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.

Does Colour Preference Have a Role in Colour Term Acquisition?

Science.gov (United States)

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

2009-01-01

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

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.

Colour scheme an exploration of the indeterminate space of colour

OpenAIRE

Varga, Tania Elke

2017-01-01

Colour Scheme examines the potential for colour to be understood as a relational and therefore, indeterminate space. The CMYK process colour model is reworked to investigate the idea of colour as an indeterminate space. In proposing that process colour can be understood as a fluid and relational system I draw attention to the unquantifiable and qualitative nature of colour. Colour can be understood as a verb, and as such may be thought of as an active substance. This understanding of col...

Validation of a colour rendering index based on memory colours

OpenAIRE

Smet, Kevin; Jost-Boissard, Sophie; Ryckaert, Wouter; Deconinck, Geert; Hanselaer, Peter

2010-01-01

In this paper the performance of a colour rendering index based on memory colours is investigated in comparison with the current CIE Colour Rendering Index, the NIST Colour Quality Scale and visual appreciation results obtained at CNRS at Lyon University for a set of 3000K and 4000K LED light sources. The Pearson and Spearman correlation coefficients between each colour rendering metric and the two sets of visual results were calculated. It was found that the memory colour based colour render...

Multispectral colour analysis for quantitative evaluation of pseudoisochromatic color deficiency tests

Science.gov (United States)

Ozolinsh, Maris; Fomins, Sergejs

2010-11-01

Multispectral color analysis was used for spectral scanning of Ishihara and Rabkin color deficiency test book images. It was done using tunable liquid-crystal LC filters built in the Nuance II analyzer. Multispectral analysis keeps both, information on spatial content of tests and on spectral content. Images were taken in the range of 420-720nm with a 10nm step. We calculated retina neural activity charts taking into account cone sensitivity functions, and processed charts in order to find the visibility of latent symbols in color deficiency plates using cross-correlation technique. In such way the quantitative measure is found for each of diagnostics plate for three different color deficiency carrier types - protanopes, deutanopes and tritanopes. Multispectral color analysis allows to determine the CIE xyz color coordinates of pseudoisochromatic plate design elements and to perform statistical analysis of these data to compare the color quality of available color deficiency test books.

Incorporating Colour Information for Computer-Aided Diagnosis of Melanoma from Dermoscopy Images: A Retrospective Survey and Critical Analysis

Directory of Open Access Journals (Sweden)

Ali Madooei

2016-01-01

Full Text Available Cutaneous melanoma is the most life-threatening form of skin cancer. Although advanced melanoma is often considered as incurable, if detected and excised early, the prognosis is promising. Today, clinicians use computer vision in an increasing number of applications to aid early detection of melanoma through dermatological image analysis (dermoscopy images, in particular. Colour assessment is essential for the clinical diagnosis of skin cancers. Due to this diagnostic importance, many studies have either focused on or employed colour features as a constituent part of their skin lesion analysis systems. These studies range from using low-level colour features, such as simple statistical measures of colours occurring in the lesion, to availing themselves of high-level semantic features such as the presence of blue-white veil, globules, or colour variegation in the lesion. This paper provides a retrospective survey and critical analysis of contributions in this research direction.

Restoration of vision in the pde6β-deficient dog, a large animal model of rod-cone dystrophy.

Science.gov (United States)

Petit, Lolita; Lhériteau, Elsa; Weber, Michel; Le Meur, Guylène; Deschamps, Jack-Yves; Provost, Nathalie; Mendes-Madeira, Alexandra; Libeau, Lyse; Guihal, Caroline; Colle, Marie-Anne; Moullier, Philippe; Rolling, Fabienne

2012-11-01

Defects in the β subunit of rod cGMP phosphodiesterase 6 (PDE6β) are associated with autosomal recessive retinitis pigmentosa (RP), a childhood blinding disease with early retinal degeneration and vision loss. To date, there is no treatment for this pathology. The aim of this preclinical study was to test recombinant adeno-associated virus (AAV)-mediated gene addition therapy in the rod-cone dysplasia type 1 (rcd1) dog, a large animal model of naturally occurring PDE6β deficiency that strongly resembles the human pathology. A total of eight rcd1 dogs were injected subretinally with AAV2/5RK.cpde6β (n = 4) or AAV2/8RK.cpde6β (n = 4). In vivo and post-mortem morphological analysis showed a significant preservation of the retinal structure in transduced areas of both AAV2/5RK.cpde6β- and AAV2/8RK.cpde6β-treated retinas. Moreover, substantial rod-derived electroretinography (ERG) signals were recorded as soon as 1 month postinjection (35% of normal eyes) and remained stable for at least 18 months (the duration of the study) in treated eyes. Rod-responses were undetectable in untreated contralateral eyes. Most importantly, dim-light vision was restored in all treated rcd1 dogs. These results demonstrate for the first time that gene therapy effectively restores long-term retinal function and vision in a large animal model of autosomal recessive rod-cone dystrophy, and provide great promise for human treatment.

Rethinking Colour Constancy.

Directory of Open Access Journals (Sweden)

Alexander D Logvinenko

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

Rethinking Colour Constancy.

Science.gov (United States)

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

2015-01-01

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

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.

Iron-Deficiency Anemia

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Full Text Available ... NHLBI News NHLBI in the Press Research Features All Events Past Events Upcoming Events About NHLBI About NHLBI Home Mission and Strategic Vision ... deficient Donors: Recovery and Storage Quality. Learn more about ... trial . View all trials from ClinicalTrials.gov . Visit Children and Clinical ...

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

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.

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.

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.

Tunnel Vision in Environmental Management.

Science.gov (United States)

Miller, Alan

1982-01-01

Discusses problem-solving styles in environmental management and the specific deficiencies in these styles that might be grouped under the label "tunnel vision," a form of selective attention contributing to inadequate problem-formulation, partial solutions to complex problems, and generation of additional problems. Includes educational…

The effect of highly potent, static magnetic fields used in magnetic resonance tomography (MRT) on the red-green vision of man

International Nuclear Information System (INIS)

Hancken, G.C.W.

1989-01-01

The ability of red-green differentiation before and after MRT exposure to a static magnetic field of a potency of 0.5 Tesla was examined in a total of 32 volunteers and contrastet to that of 128 further test persons before and after CT, linear accelerator irradiation and ultrasonography as well as to findings revealed in a control group. The greatest number of significant colour misjudgements was seen in the MRT group, where 57% of patients had deteriorated colour vision. Volunteers treated at CT units or linear accelerators also showed deviations from the normal red-green vision in 48.5% and 38.7% of cases. In the ultrasound and control groups, no more than 25% and 13.3% of the values measured using the anomaloscope suggested changes from normal. Exposure to a 0.5 Tesla magnetic field led to slight shifts in colour vision for a great number of patients. These appear to be brought about by light-sensitive photoreceptors in the retinal cone cells that respond to magnetic field influences. Theories about the underlying mechanisms are explained and discussed. The results obtained in the ultrasound and control groups have, however, also made evident that some individuals are prone to changes in colour vision without having been exposed to any measurable physical influences. These appear to be chiefly attributable to factors like stress. It would be most interesting to know to which extent study results such as these are distorted by personal perceptions and mental factors. (orig./MG) [de

Colour in a larger perspective: the rebirth of Gestalt psychology.

Science.gov (United States)

Spillmann, L

1997-01-01

This overview takes the reader from the classical contrast and assimilation studies of the past to today's colour research, in a broad sense, with its renewed emphasis on the phenomenological qualities of visual perception. It shows how the shift in paradigm from local to global effects in single-unit recordings prompted a reappraisal of appearance in visual experiments, not just in colour, but in the perception of motion, texture, and depth as well. Gestalt ideas placed in the context of modern concepts are shown to inspire psychophysicists, neurophysiologists, and computational vision scientists alike. Feedforward, horizontal interactions, and feedback are discussed as potential neuronal mechanisms to account for phenomena such as uniform surfaces, filling-in, and grouping arising from processes beyond the classical receptive field. A look forward towards future developments in the field of figure-ground segregation (Gestalt formation) concludes the article.

Voltage-controlled colour-tunable microcavity OLEDs with enhanced colour purity

International Nuclear Information System (INIS)

Choy, Wallace C H; Niu, J H; Li, W L; Chui, P C

2008-01-01

The emission spectrum of single-unit voltage-controlled colour-tunable organic light emitting devices (OLEDs) has been theoretically and experimentally studied. Our results show that by introducing the microcavity structure, the colour purity of not only the destination colour but also the colour-tunable route can be enhanced, while colour purity is still an issue in typical single-unit voltage-controlled colour-tunable OLEDs. With the consideration of the periodical cycling of resonant wavelength and absorption loss of the metal electrodes, the appropriate change in the thickness of the microcavity structure has been utilized to achieve voltage-controlled red-to-green and red-to-blue colour-tunable OLEDs without adding dyes or other organic materials to the OLEDs

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...... colour class, and another which allows the recolouring of all vertices that belong to one of a given number of colour classes. Our results extend known results concerning b-colourings and the associated b-chromatic number. (C) 2011 Elsevier B.V. All rights reserved....

Colour as a signal for entraining the mammalian circadian clock.

Directory of Open Access Journals (Sweden)

Lauren Walmsley

2015-04-01

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

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.

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...... colours and recent nanofabrication developments, comparing technology-performance indicators for traditional and nanophotonic colour technologies. The structures of interest include diffraction gratings, nanoaperture arrays, thin films, and multilayers and structures that support Mie resonances...... and whispering-gallery modes. We discuss plasmonic colour nanotechnology based on localized surface plasmon resonances, such as gap plasmons and hybridized disk–hole plasmons, which allow for colour printing with sub-diffraction resolution. We also address a range of fabrication approaches that enable large...

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.

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

Science.gov (United States)

Mecklenbräuker, S; Hupbach, A; Wippich, W

2001-11-01

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

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

Fast polarimetric dehazing method for visibility enhancement in HSI colour space

Science.gov (United States)

Zhang, Wenfei; Liang, Jian; Ren, Liyong; Ju, Haijuan; Bai, Zhaofeng; Wu, Zhaoxin

2017-09-01

Image haze removal has attracted much attention in optics and computer vision fields in recent years due to its wide applications. In particular, the fast and real-time dehazing methods are of significance. In this paper, we propose a fast dehazing method in hue, saturation and intensity colour space based on the polarimetric imaging technique. We implement the polarimetric dehazing method in the intensity channel, and the colour distortion of the image is corrected using the white patch retinex method. This method not only reserves the detailed information restoration capacity, but also improves the efficiency of the polarimetric dehazing method. Comparison studies with state of the art methods demonstrate that the proposed method obtains equal or better quality results and moreover the implementation is much faster. The proposed method is promising in real-time image haze removal and video haze removal applications.

Colour Studies

African Journals Online (AJOL)

DR Nneka

2015-04-14

Apr 14, 2015 ... failure of the student to differentiate what is of particular concern to him or her, and .... perception of the physical appearance of colour and our ..... Colour is perceived in different modes and dimension and has derivative ..... which pigment colours can effectively depict existing realities, express emotions and.

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

OpenAIRE

Derek H. Arnold; Signy V. Wegener; Francesca Brown; Jason B. Mattingley

2011-01-01

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 presenta...

Color vision deficiencies and the child's willingness for visual activity: preliminary research

Science.gov (United States)

Geniusz, Malwina; Szmigiel, Marta; Geniusz, Maciej

2017-09-01

After a few weeks a newborn baby can recognize high contrasts in colors like black and white. They reach full color vision at the age of circa six months. Matching colors is the next milestone. Most children can do it at the age of two. Good color vision is one of the factors which indicate proper development of a child. Presented research shows the correlation between color vision and visual activity. The color vision of a group of children aged 3-8 was examined with saturated Farnsworth D-15. Fransworth test was performed twice - in a standard version and in a magnetic version. The time of completing standard and magnetic tests was measured. Furthermore, parents of subjects answered questions checking the children's visual activity in 1 - 10 scale. Parents stated whether the child willingly watched books, colored coloring books, put puzzles or liked to play with blocks etc. The Fransworth D-15 test designed for color vision testing can be used to test younger children from the age of 3 years. These are preliminary studies which may be a useful tool for further, more accurate examination on a larger group of subjects.

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

Science.gov (United States)

Delhey, Kaspar

2015-01-01

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

Detection of coloured tracks of heavy ion particles using photographic colour film

International Nuclear Information System (INIS)

Kuge, K.; Yasuda, N.; Kumagai, H.; Nakazawa, K.; Kobayashi, T.; Aoki, N.; Hasegawa, A.

2001-01-01

A photographic colour film, which was exposed to heavy ions, reveals a coloured dye image of the ion tracks. Since the colour film consists of several layers and different colours appear on each layer, three-dimensional information on the tracks in the layers can be obtained by the colour image. Previously, we have reported the method for which the tracks in different colours represented differences of track depth and we also discussed the disadvantages of using commercial colour films. Here we present the procedure for a self-made photographic coating and the development formula which can overcome the disadvantages

Colour printing techniques

OpenAIRE

Parraman, C.

2017-01-01

Invited chapter in the book Colour Design: Theories and Applications. In PART 3 COLOUR, DESIGN AND COLORATION this chapter covers:\\ud - Hardcopy colour: analogue versus digital\\ud - Colour theory in relation to printing\\ud - Overview of halftoning and digital print technologies\\ud - Overview and development of inks\\ud - Inkjet papers and inks\\ud - Recent and future trends in colour, printing inks and hardware.\\ud \\ud This book differs from other existing books in the field, with the aim of an...

Colour intransparency and the cross sections for colour-singlet and colour-octet hadrons in the Low-Nussinov model

International Nuclear Information System (INIS)

Dolejsi, J.; Huefner, J.

1992-01-01

The dependence of cross sections on the colour state of the colliding hadrons is investigated within the Low-Nussinov model of two-gluon exchange. The total cross sections for colour-octet hadrons are practically constant as functions of the hadronic radii, while they tend to zero when the radii of the colour-singlet hadrons approach zero. The slope parameter of the differential elastic cross sections for small momentum transfers is rather insensitive to the colour structure of the colliding hadrons. The integrated colour exchange cross section is calculated. (orig.)

The eyes and vision of butterflies.

Science.gov (United States)

Arikawa, Kentaro

2017-08-15

Butterflies use colour vision when searching for flowers. Unlike the trichromatic retinas of humans (blue, green and red cones; plus rods) and honeybees (ultraviolet, blue and green photoreceptors), butterfly retinas typically have six or more photoreceptor classes with distinct spectral sensitivities. The eyes of the Japanese yellow swallowtail (Papilio xuthus) contain ultraviolet, violet, blue, green, red and broad-band receptors, with each ommatidium housing nine photoreceptor cells in one of three fixed combinations. The Papilio eye is thus a random patchwork of three types of spectrally heterogeneous ommatidia. To determine whether Papilio use all of their receptors to see colours, we measured their ability to discriminate monochromatic lights of slightly different wavelengths. We found that Papilio can detect differences as small as 1-2 nm in three wavelength regions, rivalling human performance. We then used mathematical modelling to infer which photoreceptors are involved in wavelength discrimination. Our simulation indicated that the Papilio vision is tetrachromatic, employing the ultraviolet, blue, green and red receptors. The random array of three ommatidial types is a common feature in butterflies. To address the question of how the spectrally complex eyes of butterflies evolved, we studied their developmental process. We have found that the development of butterfly eyes shares its molecular logic with that of Drosophila: the three-way stochastic expression pattern of the transcription factor Spineless determines the fate of ommatidia, creating the random array in Papilio. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

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...

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

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.

Measurements and modelling of the influence of dentine colour and enamel on tooth colour.

Science.gov (United States)

Battersby, Paul D; Battersby, Stephen J

2015-03-01

We provide a quantitative predictive model for the extent to which coloured dentine, visible through the enamel, contributes to tooth colour. Our model uses (L(*),a(*),b(*)) measurements rather than spectral measurements. We have used a model system, composed of a slice of bovine enamel placed on top of coloured paper. We have measured the colour of the enamel-paper combination, as an analogue for a tooth, and have related this to the colour of the paper, as an analogue for dentine. By changing the paper colour, we have been able to explore how the colour of dentine determines tooth colour, according to our model system. We have also compared hydrated and desiccated samples. In qualitative terms, superimposing the enamel on top of the paper increases the "lightness" for all colours tested except white while simultaneously reducing the chromaticity, a measure of the extent to which the colour differs from grey. Desiccated enamel is much more effective at increasing the lightness and reducing the chromaticity than hydrated enamel. Quantitatively, our measurements are reproduced by the mathematical model we have developed to within 2% in "lightness" and about 8% in chromaticity. We are able to predict the colour of an analogue for a tooth, composed of bovine enamel and coloured paper, from the colour of an analogue for the dentine, the coloured paper alone, with good accuracy. This understanding provides insights into the role of dentine colour in determining tooth colour. Our work helps quantify the importance of dentine colour, compared to other, extrinsic causes of colour, such as staining, in determining the visible colour of teeth. Our predicted colours represent a baseline to which extrinsic sources will add. Copyright © 2015. Published by Elsevier Ltd.

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

Colour Blocking: Disregarding Traditional Artistic Colour Harmonies ...

African Journals Online (AJOL)

A development in the world of design – costume, fashion, graphics, architecture and general decor whereby traditional colour harmonies are reengineered to suite the taste of the time engages the attention of the paper. The trending phenomenon popularly referred to as 'colour blocking' involves the use of bright ...

Colour perception in ADHD

NARCIS (Netherlands)

Banaschewski, T.; Ruppert, S; Tannock, R.; Albrecht, B.; Becker, A.; Uebel, H.; Sergeant, J.A.; Rothenberger, A.

2006-01-01

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

Innate colour preference, individual learning and memory retention in the ant Camponotus blandus.

Science.gov (United States)

Yilmaz, Ayse; Dyer, Adrian G; Rössler, Wolfgang; Spaethe, Johannes

2017-09-15

Ants are a well-characterized insect model for the study of visual learning and orientation, but the extent to which colour vision is involved in these tasks remains unknown. We investigated the colour preference, learning and memory retention of Camponotus blandus foragers under controlled laboratory conditions. Our results show that C. blandus foragers exhibit a strong innate preference for ultraviolet (UV, 365 nm) over blue (450 nm) and green (528 nm) wavelengths. The ants can learn to discriminate 365 nm from either 528 nm or 450 nm, independent of intensity changes. However, they fail to discriminate between 450 nm and 528 nm. Modelling of putative colour spaces involving different numbers of photoreceptor types revealed that colour discrimination performance of individual ants is best explained by dichromacy, comprising a short-wavelength (UV) receptor with peak sensitivity at about 360 nm, and a long-wavelength receptor with peak sensitivity between 470 nm and 560 nm. Foragers trained to discriminate blue or green from UV light are able to retain the learned colour information in an early mid-term (e-MTM), late mid-term (l-MTM), early long-term (e-LTM) and late long-term (l-LTM) memory from where it can be retrieved after 1 h, 12 h, 24 h, 3 days and 7 days after training, indicating that colour learning may induce different memory phases in ants. Overall, our results show that ants can use chromatic information in a way that should promote efficient foraging in complex natural environments. © 2017. Published by The Company of Biologists Ltd.

COLOUR THEREPY-BOON TO MANKIND

OpenAIRE

Dr.Sajan Kurien Mathew

2017-01-01

Colour Therapy is a complementary therapy for which there is evidence dating back thousands of years to the ancient cultures of Egypt, China and India. Colour is simply light of varying wavelengths, thus each colour has its own particular wavelength and energy. "Colour affects our life. Colour is physical..........we see it. Colour communicates............we recieve information from the language of colour. Colour is emotional..........it evokes our feeling."1 The energy relating to each of th...

Memory colours and colour quality evaluation of conventional and solid-state lamps.

Science.gov (United States)

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

2010-12-06

A colour quality metric based on memory colours is presented. The basic idea is simple. The colour quality of a test source is evaluated as the degree of similarity between the colour appearance of a set of familiar objects and their memory colours. The closer the match, the better the colour quality. This similarity was quantified using a set of similarity distributions obtained by Smet et al. in a previous study. The metric was validated by calculating the Pearson and Spearman correlation coefficients between the metric predictions and the visual appreciation results obtained in a validation experiment conducted by the authors as well those obtained in two independent studies. The metric was found to correlate well with the visual appreciation of the lighting quality of the sources used in the three experiments. Its performance was also compared with that of the CIE colour rendering index and the NIST colour quality scale. For all three experiments, the metric was found to be significantly better at predicting the correct visual rank order of the light sources (p < 0.1).

Colour Perception in ADHD

Science.gov (United States)

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

2006-01-01

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

Colour and magnetic monopoles

International Nuclear Information System (INIS)

Corrigan, E.; Olive, D.

1976-01-01

If the exact gauge symmetry of nature consists of the U(1)sub(EM) generated by the electric charge operator Q and the colour group K, with Q a colour singlet, then, if g is a possible magnetic charge, exp(4πigQ) must equal an element of the colour group. For colour singlet particles this reduces to Dirac's condition eg = n/2. In general, possible monopoles correspond to points of intersection of the colour and electromagnetic groups. If the colour group is semi-simple and compact, there can at most be a finite number p of such points (p = N if K = SU(N)). The existence of non-trivial (not equal to unity) solutions to our condition means that there must be fractionally charged (with p the fraction) coloured particles and magnetic monopoles emanating colour magnetic flux as well as electromagnetic flux. (Auth.)

Colour perception in ADHD

OpenAIRE

Banaschewski, T.; Ruppert, S; Tannock, R.; Albrecht, B.; Becker, A.; Uebel, H.; Sergeant, J.A.; Rothenberger, A.

2006-01-01

Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children with ADHD and 13 healthy peers matched for age, gender, and IQ, using the Farnsworth-Munsell 100 Hue Test (FMT) and the Stroop-Colour-Word test. Childr...

Measuring colour

National Research Council Canada - National Science Library

Hunt, R. W. G; Pointer, Michael, Ph. D

2011-01-01

... industries.Building upon the success of earlier editions, the 4th edition of [start italics]Measuring Colour[end italics] has been updated throughout with new chapters on colour rendering by light sources...

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.

SVM Pixel Classification on Colour Image Segmentation

Science.gov (United States)

Barui, Subhrajit; Latha, S.; Samiappan, Dhanalakshmi; Muthu, P.

2018-04-01

The aim of image segmentation is to simplify the representation of an image with the help of cluster pixels into something meaningful to analyze. Segmentation is typically used to locate boundaries and curves in an image, precisely to label every pixel in an image to give each pixel an independent identity. SVM pixel classification on colour image segmentation is the topic highlighted in this paper. It holds useful application in the field of concept based image retrieval, machine vision, medical imaging and object detection. The process is accomplished step by step. At first we need to recognize the type of colour and the texture used as an input to the SVM classifier. These inputs are extracted via local spatial similarity measure model and Steerable filter also known as Gabon Filter. It is then trained by using FCM (Fuzzy C-Means). Both the pixel level information of the image and the ability of the SVM Classifier undergoes some sophisticated algorithm to form the final image. The method has a well developed segmented image and efficiency with respect to increased quality and faster processing of the segmented image compared with the other segmentation methods proposed earlier. One of the latest application result is the Light L16 camera.

The colours of CERN

CERN Multimedia

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 ...

Subjective estimates of colour attributes for surface colours

NARCIS (Netherlands)

Ishak, I.G.H.; Bouma, H.; van Bussel, H.J.J.

1970-01-01

Subjective estimates of hue, saturation, and lightness are reported for sixty coloured Munsell samples, shown against seven backgrounds (black, grey, white, red, yellow, green, and blue) as judged by two observers. The results show the adequacy of this method for studies on colour appearance. The

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

Science.gov (United States)

Farroni, Abel; Buera, María Del Pilar

2012-12-01

The aim of this work was to study colour and surface fluorescence development in relation to the chemical markers for the Maillard reaction at the cooking, flaking and toasting stages of cornflake production process. Colour was measured by a calibrated computer vision system. Surface fluorescence was measured on compressed samples. Aqueous extracted Maillard reaction markers (hydroxymethylfurfural, carboxymethyl-lysine, absorbance at 420nm and total fluorescence) were measured on protease hydrolyzed samples. Sample microstructure was observed by scanning electron microscopy. During cooking the colour coordinates L(∗) and b(∗) decreased and a(∗) increased. After flaking, the samples appeared lighter, while the pigment concentration, fluorescence and hydroxymethylfurfural did not change. Toasting generated bubbles in the matrix and L(∗) apparently increased, although brown pigment concentration increased. Pigment concentration did not correlate with surface colour due to the destruction or generation of interfaces. Surface and microstructure effects can be avoided by milling and compressing the samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

Hypersensitivity reactions to food colours with special reference to the natural colour annatto extract (butter colour).

Science.gov (United States)

Mikkelsen, H; Larsen, J C; Tarding, F

1978-01-01

It is well known that synthetic food colours especially some azo dyes can provoke hypersensitivity reactions such as urticaria, angioneurotic oedema, and astma (Michaëlsson and Juhlin, 1973, Granholt and Thune, 1975). Natural food colours are scarcely investigated with respect to potential allergic properties. Annatto extract, a commonly used food colour in edible fats e.g. butter, has been tested in patients. Among 61 consecutive patients suffereing from chornic urticaria and/or angioneurotic oedema 56 patients were orally provoked by annatto extract during elimination diet. Challenge was performed with a dose equivalent to the amount used in 25 grammes of butter. Twentysix per cent of the patients reacted to this colour 4 hours (SD: 2,6) after intake. Similar challenges with synthetic dyes showed the following results: Tartrazine 11%, Sunset Yellow FCF 17%, Food Red 17 16%, Amaranth 9%, Ponceau 4 R 15%, Erythrosine 12% and Brillant Blue FCF 14%. The present study indicates that natural food colours may induce hypersensitivity reactions as frequent as synthetic dyes.

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.

Cadmium colours: composition and properties

International Nuclear Information System (INIS)

Paulus, J.; Knuutinen, U.

2004-01-01

The composition and the properties of cadmium aquarelle colours are discussed. The examined colours were 24 different aquarelle cadmium colours from six different manufacturers. The colours ranged from light, bright yellows to dark, deep-red tones. The aim of this research was to find out if the pigments contain cadmium salts: sulphides and/or selenides. This information will help in choosing watercolours in conservation processes. Today, aquarelle colours not containing cadmium pigments are being sold as cadmium colours; thus their properties might be different from actual cadmium colours. The aim of the research was to verify that the colour samples contained cadmium pigments and to estimate their compositions and ageing properties. Element analyses were performed from colour samples using micro-chemical tests and X-ray fluorescence measurements. Thin-layer chromatography was used for analysing gum Arabic as a possible binding medium in the chosen colour samples. Through ageing tests, the resistance of the colour samples to the exposure to light, heat and humidity was studied. Visible-light spectroscopy was used in determining the hues and hue changes of the aquarelle colour samples. The spectrophotometer used the CIE L * a * b * tone colour measuring system. From the colour measurements the changes in the lightness/darkness, the redness, the yellowness and the saturation of the samples were examined. (orig.)

Colour atlas on forest disease. Diagnosis of tree diseases. Farbatlas Waldschaeden. Diagnose von Baumkrankheiten

Energy Technology Data Exchange (ETDEWEB)

Hartmann, G.; Winter, K.; Nienhaus, F.; Butin, H.

1988-01-01

The 'Colour Atlas on Forest Disease' facilitates the diagnosis of syndromes due to different causes in 16 genera or species of forest trees. It contains a selection of more than 200 important, frequent, or conspicuous disease phenomena. These include: in a ratio of 8 percent partly novel, complex diseases due to causes not entirely elucidated, 35 percent known forms of damage of abiotic origin (extreme weather conditions, nutrient deficiency, classical damage due to environmental pollution and de-icing salt, damage through herbicides), and 57 percent diseases and harm of biotic origin (fungal infections, infestation with insect pest, bacterial, mycoplasmal, rickettsia-type and viral diseases, other damage). 418 colour photographs show characteristic features of tree diseases and provide clues to causes and possible alternative diseases liable to be mixed up with the actual one. The selection decided on is restricted to symptoms visible externally in the area of the crowns as far as they are distinguishable in the field. (orig./MG) With 418 colour photographs.

Colour categories are reflected in sensory stages of colour perception when stimulus issues are resolved

Science.gov (United States)

He, Xun; Franklin, Anna

2017-01-01

Debate exists about the time course of the effect of colour categories on visual processing. We investigated the effect of colour categories for two groups who differed in whether they categorised a blue-green boundary colour as the same- or different-category to a reliably-named blue colour and a reliably-named green colour. Colour differences were equated in just-noticeable differences to be equally discriminable. We analysed event-related potentials for these colours elicited on a passive visual oddball task and investigated the time course of categorical effects on colour processing. Support for category effects was found 100 ms after stimulus onset, and over frontal sites around 250 ms, suggesting that colour naming affects both early sensory and later stages of chromatic processing. PMID:28542426

Minimum Colour Differences Required To Recognise Small Objects On A Colour CRT

Science.gov (United States)

Phillips, Peter L.

1985-05-01

Data is required to assist in the assessment, evaluation and optimisation of colour and other displays for both military and general use. A general aim is to develop a mathematical technique to aid optimisation and reduce the amount of expensive hardware development and trials necessary when introducing new displays. The present standards and methods available for evaluating colour differences are known not to apply to the perception of typical objects on a display. Data is required for irregular objects viewed at small angular subtense ((1°) and relating the recognition of form rather than colour matching. Therefore laboratory experiments have been carried out using a computer controlled CRT to measure the threshold colour difference that an observer requires between object and background so that he can discriminate a variety of similar objects. Measurements are included for a variety of background and object colourings. The results are presented in the CIE colorimetric system similar to current standards used by the display engineer. Apart from the characteristic small field tritanopia, the results show that larger colour differences are required for object recognition than those assumed from conventional colour discrimination data. A simple relationship to account for object size and background colour is suggested to aid visual performance assessments and modelling.

Chromogenic in situ hybridization for Her-2/neu-oncogene in breast cancer: comparison of a new dual-colour chromogenic in situ hybridization with immunohistochemistry and fluorescence in situ hybridization.

Science.gov (United States)

Mayr, Doris; Heim, Sibylle; Weyrauch, Kerstin; Zeindl-Eberhart, Evelyn; Kunz, Anne; Engel, Jutta; Kirchner, Thomas

2009-12-01

Her-2/neu testing is used as a marker for Herceptin therapy. The aim was to investigate new dual-colour chromogenic in situ hybridization (CISH), in a large number of breast carcinomas (n = 205) with DNA-specific dual-colour probes (ZytoVision, Bremerhaven, Germany) and to compare the results with immunohistochemistry (n = 205) and fluorescence in situ hybridization (FISH) (n = 129). Paraffin-embedded tissue of 205 patients was used. After immunohistochemistry with a focus on immunohistochemically uncertain cases, Her-2/neu amplification using dual-colour CISH (ZytoVision) was analysed. Validation by FISH was performed. The results were: immunohistochemistry, 27.8% with strong expression, 53.7% with uncertain overexpression and 18.5% with no expression; FISH, 25.6% amplified and 74.4% negative; CISH, 35.6% amplified, 62.9% negative and 1.5% not evaluable. Comparison of immunohistochemistry with CISH: CISH negative in 100% with immunohistochemistry 0/1+, amplified in 82.5% with immunohistochemistry 3+; 5.9% contradictory results: 4.4% immunohistochemistry 3+ and negative by CISH, 1.5% negative in immunohistochemistry but amplified by CISH; FISH (129 cases), 8.5% contradictory results to immunohistochemistry, 6.2% immunohistochemistry 3+ and negative by FISH, 2.3% negative by immunohistochemistry and amplified by FISH; comparison of CISH and FISH, 94.6% same results, 3.9% different ones, 1.6% CISH not analysable. CISH, using dual-colour probes (ZytoVision) is as good as FISH for Her-2/neu analysis. The few discrepant results are likely to be caused by polysomy or tumour heterogeneity.

Operational Colour Vision in the Modern Aviation Environment (la Vision des couleurs dans l’environnement aeronautique operationnel d’ aujourd hui)

Science.gov (United States)

2001-03-01

recommended. The Nagel II is no longer in production . Advantages: test has a long and hallowed history that is well respected. Disadvantages: expensive...Illuminator (Catalog No. 1388R) from Richmond Products , 1021 Rogers Circle, Suite 6, Boca Raton FL, 33487-2894. Phones:1-800-448-4538 and 407-994-2112...III Antineoplastics Mercaptopurine II Vincristine II Antirheumatics Ibuprofen II Colours appear faded Indomethacin III Antispasmodics

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

Science.gov (United States)

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

2016-01-01

People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have particularly strong affective connotations. To test whether colour choices can be driven by emotion, we investigated whether and how colour hue, brightness, and saturation are systematically associated with bodily expressions of positive (joy) and negative (fear) emotions. Twenty-five non-colour-blind participants viewed videos of these expressions and selected for each video the most appropriate colour using colour sliders providing values for hue, brightness, and saturation. The overall colour choices were congruent with the expressed emotion--that is, participants selected brighter and more saturated colours for joy expressions than for fear expressions. Also, colours along the red-yellow spectrum were deemed more appropriate for joy expressions and cyan-bluish hues for fear expressions. The current study adds further support to the role of emotion in colour choices by (a) showing that emotional information is spontaneously used in an unconstrained choice setting, (b) extending to ecologically valid stimuli occurring in everyday encounters (dressed bodies), and (c) suggesting that all colour parameters are likely to be important when processing affective nonverbal person information, though not independently from each other.

The control of attentional target selection in a colour/colour conjunction task

OpenAIRE

Berggren, Nick; Eimer, Martin

2016-01-01

To investigate the time course of attentional object selection processes in visual search tasks where targets are defined by a combination of features from the same dimension, we measured the N2pc component as an electrophysiological marker of attentional object selection during colour/colour conjunction search. In Experiment 1, participants searched for targets defined by a combination of two colours, while ignoring distractor objects that matched only one of these colours. Reliable N2pc com...

Does Daltonism Influence Young Children's Learning?

Science.gov (United States)

Suero, M.I.; Perez, A.L.; Diaz, F.; Montanero, M.; Pardo, P.J.; Gil, J.; Palomino, M.I.

2005-01-01

Anomalies in colour vision constitute a particular type of sensory deficiency whose influence in educational contexts has attracted surprisingly little research attention given its ubiquitous use in various learning activities as a code, an aid, or even as the focus of the activity itself, especially during early education. We here describe a…

Blue colour preference in honeybees distracts visual attention for learning closed shapes.

Science.gov (United States)

Morawetz, Linde; Svoboda, Alexander; Spaethe, Johannes; Dyer, Adrian G

2013-10-01

Spatial vision is an important cue for how honeybees (Apis mellifera) find flowers, and previous work has suggested that spatial learning in free-flying bees is exclusively mediated by achromatic input to the green photoreceptor channel. However, some data suggested that bees may be able to use alternative channels for shape processing, and recent work shows conditioning type and training length can significantly influence bee learning and cue use. We thus tested the honeybees' ability to discriminate between two closed shapes considering either absolute or differential conditioning, and using eight stimuli differing in their spectral characteristics. Consistent with previous work, green contrast enabled reliable shape learning for both types of conditioning, but surprisingly, we found that bees trained with appetitive-aversive differential conditioning could additionally use colour and/or UV contrast to enable shape discrimination. Interestingly, we found that a high blue contrast initially interferes with bee shape learning, probably due to the bees innate preference for blue colours, but with increasing experience bees can learn a variety of spectral and/or colour cues to facilitate spatial learning. Thus, the relationship between bee pollinators and the spatial and spectral cues that they use to find rewarding flowers appears to be a more rich visual environment than previously thought.

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

Science.gov (United States)

Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M; Althaus, Betty; Anil, Selin; Dael, Nele

2016-01-01

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.

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.

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

Science.gov (United States)

Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M.; Althaus, Betty; Anil, Selin; Dael, Nele

2016-01-01

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. PMID:27022909

Colour-Temperature Correspondences: When Reactions to Thermal Stimuli Are Influenced by Colour

Science.gov (United States)

Ho, Hsin-Ni; Van Doorn, George H.; Kawabe, Takahiro; Watanabe, Junji; Spence, Charles

2014-01-01

In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant’s responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented. PMID:24618675

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

About Coloured Cold Asphaltic Mixtures

Directory of Open Access Journals (Sweden)

Loredana Judele

2008-01-01

Full Text Available The first coloured bitumen was obtained by using bitumen from Peru and then bitumen from the Middle East, with a low content of asphaltenes, also called "colourable" bitumens. The colours obtained by adding iron oxides led nevertheless to dark colours, due to the presence of asphaltenes. Nowadays the coloured asphalt is obtained from synthesis binders with translucent aspect. The colours are obtained by adding inorganic pigments, mainly iron oxide for red, chromic oxide for green, titanic dioxide for white. The properties and behaviour of the coloured bitumen during its lifetime are comparable with the ones of classic bitumen, sometimes even better.

Evaluation of Next-Generation Vision Testers for Aeromedical Certification of Aviation Personnel

Science.gov (United States)

2009-07-01

measure distant, intermediate, and near acuity. The slides are essentially abbreviated versions of the Early Treatment for Diabetic Retinopathy Study...over, requiring intermediate vision testing and 12 were color deficient. Analysis was designed to detect statistically significant differences between...Vertical Phoria (Right & Left Hyperphoria) Test scores from each of the vision testers were collated and analyzed. Analysis was designed to detect

Topographical coloured plasmonic coins

OpenAIRE

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

2016-01-01

Plasmonic resonances in metallic nanoparticles have been used since antiquity to colour glasses. The use of metal nanostructures for surface colourization has attracted considerable interest following recent developments in plasmonics. However, current top-down colourization methods are not ideally suited to large-scale industrial applications. Here we use a bottom-up approach where picosecond laser pulses can produce a full palette of non-iridescent colours on silver, gold, copper and alumin...

Molluscan shell colour.

Science.gov (United States)

Williams, Suzanne T

2017-05-01

The phylum Mollusca is highly speciose, and is the largest phylum in the marine realm. The great majority of molluscs are shelled, including nearly all bivalves, most gastropods and some cephalopods. The fabulous and diverse colours and patterns of molluscan shells are widely recognised and have been appreciated for hundreds of years by collectors and scientists alike. They serve taxonomists as characters that can be used to recognise and distinguish species, however their function for the animal is sometimes less clear and has been the focus of many ecological and evolutionary studies. Despite these studies, almost nothing is known about the evolution of colour in molluscan shells. This review summarises for the first time major findings of disparate studies relevant to the evolution of shell colour in Mollusca and discusses the importance of colour, including the effects of visual and non-visual selection, diet and abiotic factors. I also summarise the evidence for the heritability of shell colour in some taxa and recent efforts to understand the molecular mechanisms underpinning synthesis of shell colours. I describe some of the main shell pigments found in Mollusca (carotenoids, melanin and tetrapyrroles, including porphyrins and bile pigments), and their durability in the fossil record. Finally I suggest that pigments appear to be distributed in a phylogenetically relevant manner and that the synthesis of colour is likely to be energetically costly. © 2016 Cambridge Philosophical Society.

NAMPT-Mediated NAD(+) Biosynthesis Is Essential for Vision In Mice.

Science.gov (United States)

Lin, Jonathan B; Kubota, Shunsuke; Ban, Norimitsu; Yoshida, Mitsukuni; Santeford, Andrea; Sene, Abdoulaye; Nakamura, Rei; Zapata, Nicole; Kubota, Miyuki; Tsubota, Kazuo; Yoshino, Jun; Imai, Shin-Ichiro; Apte, Rajendra S

2016-09-27

Photoreceptor death is the endpoint of many blinding diseases. Identifying unifying pathogenic mechanisms in these diseases may offer global approaches for facilitating photoreceptor survival. We found that rod or cone photoreceptor-specific deletion of nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in the major NAD(+) biosynthetic pathway beginning with nicotinamide, caused retinal degeneration. In both cases, we could rescue vision with nicotinamide mononucleotide (NMN). Significantly, retinal NAD(+) deficiency was an early feature of multiple mouse models of retinal dysfunction, including light-induced degeneration, streptozotocin-induced diabetic retinopathy, and age-associated dysfunction. Mechanistically, NAD(+) deficiency caused metabolic dysfunction and consequent photoreceptor death. We further demonstrate that the NAD(+)-dependent mitochondrial deacylases SIRT3 and SIRT5 play important roles in retinal homeostasis and that NAD(+) deficiency causes SIRT3 dysfunction. These findings demonstrate that NAD(+) biosynthesis is essential for vision, provide a foundation for future work to further clarify the mechanisms involved, and identify a unifying therapeutic target for diverse blinding diseases. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Optic neuropathy in a patient with pyruvate dehydrogenase deficiency

Energy Technology Data Exchange (ETDEWEB)

Small, Juan E. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Gonzalez, Guido E. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Radiology, Boston, MA (United States); Clinica Alemana de Santiago, Departmento de Imagenes, Santiago (Chile); Nagao, Karina E.; Walton, David S. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Ophthalmology, Boston, MA (United States); Caruso, Paul A. [Massachusetts Eye and Ear Infirmary and Harvard Medical School, Department of Radiology, Boston, MA (United States)

2009-10-15

Pyruvate dehydrogenase (PDH) deficiency is a genetic disorder of mitochondrial metabolism. The clinical manifestations range from severe neonatal lactic acidosis to chronic neurodegeneration. Optic neuropathy is an uncommon clinical sequela and the imaging findings of optic neuropathy in these patients have not previously been described. We present a patient with PDH deficiency with bilateral decreased vision in whom MRI demonstrated bilateral optic neuropathy and chiasmopathy. (orig.)

Optic neuropathy in a patient with pyruvate dehydrogenase deficiency

International Nuclear Information System (INIS)

Small, Juan E.; Gonzalez, Guido E.; Nagao, Karina E.; Walton, David S.; Caruso, Paul A.

2009-01-01

Pyruvate dehydrogenase (PDH) deficiency is a genetic disorder of mitochondrial metabolism. The clinical manifestations range from severe neonatal lactic acidosis to chronic neurodegeneration. Optic neuropathy is an uncommon clinical sequela and the imaging findings of optic neuropathy in these patients have not previously been described. We present a patient with PDH deficiency with bilateral decreased vision in whom MRI demonstrated bilateral optic neuropathy and chiasmopathy. (orig.)

Colour for Behavioural Success

Science.gov (United States)

Reeves, Adam

2018-01-01

Colour information not only helps sustain the survival of animal species by guiding sexual selection and foraging behaviour but also is an important factor in the cultural and technological development of our own species. This is illustrated by examples from the visual arts and from state-of-the-art imaging technology, where the strategic use of colour has become a powerful tool for guiding the planning and execution of interventional procedures. The functional role of colour information in terms of its potential benefits to behavioural success across the species is addressed in the introduction here to clarify why colour perception may have evolved to generate behavioural success. It is argued that evolutionary and environmental pressures influence not only colour trait production in the different species but also their ability to process and exploit colour information for goal-specific purposes. We then leap straight to the human primate with insight from current research on the facilitating role of colour cues on performance training with precision technology for image-guided surgical planning and intervention. It is shown that local colour cues in two-dimensional images generated by a surgical fisheye camera help individuals become more precise rapidly across a limited number of trial sets in simulator training for specific manual gestures with a tool. This facilitating effect of a local colour cue on performance evolution in a video-controlled simulator (pick-and-place) task can be explained in terms of colour-based figure-ground segregation facilitating attention to local image parts when more than two layers of subjective surface depth are present, as in all natural and surgical images. PMID:29770183

Bumblebees (Bombus terrestris) and honeybees (Apis mellifera) prefer similar colours of higher spectral purity over trained colours.

Science.gov (United States)

Rohde, Katja; Papiorek, Sarah; Lunau, Klaus

2013-03-01

Differences in the concentration of pigments as well as their composition and spatial arrangement cause intraspecific variation in the spectral signature of flowers. Known colour preferences and requirements for flower-constant foraging bees predict different responses to colour variability. In experimental settings, we simulated small variations of unicoloured petals and variations in the spatial arrangement of colours within tricoloured petals using artificial flowers and studied their impact on the colour choices of bumblebees and honeybees. Workers were trained to artificial flowers of a given colour and then given the simultaneous choice between three test colours: either the training colour, one colour of lower and one of higher spectral purity, or the training colour, one colour of lower and one of higher dominant wavelength; in all cases the perceptual contrast between the training colour and the additional test colours was similarly small. Bees preferred artificial test flowers which resembled the training colour with the exception that they preferred test colours with higher spectral purity over trained colours. Testing the behaviour of bees at artificial flowers displaying a centripetal or centrifugal arrangement of three equally sized colours with small differences in spectral purity, bees did not prefer any type of artificial flowers, but preferentially choose the most spectrally pure area for the first antenna contact at both types of artificial flowers. Our results indicate that innate preferences for flower colours of high spectral purity in pollinators might exert selective pressure on the evolution of flower colours.

Specific deficit of colour-colour short-term memory binding in sporadic and familial Alzheimer's disease.

Science.gov (United States)

Parra, Mario A; Sala, Sergio Della; Abrahams, Sharon; Logie, Robert H; Méndez, Luis Guillermo; Lopera, Francisco

2011-06-01

Short-term memory binding of visual features which are processed across different dimensions (shape-colour) is impaired in sporadic Alzheimer's disease, familial Alzheimer's disease, and in asymptomatic carriers of familial Alzheimer's disease. This study investigated whether Alzheimer's disease also impacts on within-dimension binding processes. The study specifically explored whether visual short-term memory binding of features of the same type (colour-colour) is sensitive to Alzheimer's disease. We used a neuropsychological battery and a short-term memory binding task to assess patients with sporadic Alzheimer's disease (Experiment 1), familial Alzheimer's disease (Experiment 2) due to the mutation E280A of the Presenilin-1 gene and asymptomatic carriers of the mutation. The binding task assessed change detection within arrays of unicoloured objects (Colour Only) or bicoloured objects the colours of which had to be remembered separately (Unbound Colours) or together (Bound Colours). Performance on the Bound Colours condition (1) explained the largest proportion of variance between patients (sporadic and familial Alzheimer's disease), (2) combined more sensitivity and specificity for the disease than other more traditional neuropsychological tasks, (3) identified asymptomatic carriers of the mutation even when traditional neuropsychological measures and other measures of short-term memory did not and, (4) contrary to shape-colour binding, correlated with measures of hippocampal functions. Colour-colour binding and shape-colour binding both appear to be sensitive to AD even though they seem to rely on different brain mechanisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

76 FR 25763 - Qualification of Drivers; Exemption Applications; Vision

Science.gov (United States)

2011-05-05

... with the vision deficiency: Christopher Kahl, Althea Renita Dowell, Steven DuBois, Steve Campbell... Pulido, Oliver Murphy, Jerome Smalls, Alan Jenkins, Ryan Forsythe, Terry L. Randoll, Edward Joseph... for an exemption. Thomas L. Newingham, Joseph Barlow. The following 2 applicants do not have...

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.

Colour Reproduction on Tablet Devices

Directory of Open Access Journals (Sweden)

Vladimir Zorić

2014-07-01

Full Text Available With the advent of Internet and mobile devices client services and other print production are migrating more and more to online platforms. In a recent technology changeover it is obvious that there is growing number of printers as well need from the customers for the print service providers to expand their business to online and mobile platforms. With this technological transition there are some open questions regarding the possibilities of using the tablet devices for colour soft proofing and other colour related operations. As a display devices on a hardware level there are large similarities with the desktop display devices but the operating systems which are driving them are not yet colour smart. There have been some initial attempts to characterize the colour reproduction on this type of devices and find a possibility of using them not just for information content but also for colour managed content. In this study we have tested several tablets (Apple iPad2,Asus Transformer TF101, Samsung Galaxy Tab 1 with different display and OS technology and tested a software which is intended for colour managed viewing of the reproduction. We have measured the colour reproduction of the tablets with the digital version of the GretagMacbeth ColorChecker card and have calculated the colour differences between the colour chart data and the displayed data. We have calibrated the Ipad2 with the only existing colour management tool the Spyder Gallery and we have also tested the chart display with and without the colour correction of the software. We have found that there are differences in the colour reproduction of the display technologies and that the possibilities of a real colour managed workflow has yet to be resolved on the OS level of tablet and mobile devices

Automaticity and localisation of concurrents predicts colour area activity in grapheme-colour synaesthesia.

Science.gov (United States)

Gould van Praag, Cassandra D; Garfinkel, Sarah; Ward, Jamie; Bor, Daniel; Seth, Anil K

2016-07-29

In grapheme-colour synaesthesia (GCS), the presentation of letters or numbers induces an additional 'concurrent' experience of colour. Early functional MRI (fMRI) investigations of GCS reported activation in colour-selective area V4 during the concurrent experience. However, others have failed to replicate this key finding. We reasoned that individual differences in synaesthetic phenomenology might explain this inconsistency in the literature. To test this hypothesis, we examined fMRI BOLD responses in a group of grapheme-colour synaesthetes (n=20) and matched controls (n=20) while characterising the individual phenomenology of the synaesthetes along dimensions of 'automaticity' and 'localisation'. We used an independent functional localiser to identify colour-selective areas in both groups. Activations in these areas were then assessed during achromatic synaesthesia-inducing, and non-inducing conditions; we also explored whole brain activations, where we sought to replicate the existing literature regarding synaesthesia effects. Controls showed no significant activations in the contrast of inducing > non-inducing synaesthetic stimuli, in colour-selective ROIs or at the whole brain level. In the synaesthete group, we correlated activation within colour-selective ROIs with individual differences in phenomenology using the Coloured Letters and Numbers (CLaN) questionnaire which measures, amongst other attributes, the subjective automaticity/attention in synaesthetic concurrents, and their spatial localisation. Supporting our hypothesis, we found significant correlations between individual measures of synaesthetic phenomenology and BOLD responses in colour-selective areas, when contrasting inducing against non-inducing stimuli. Specifically, left-hemisphere colour area responses were stronger for synaesthetes scoring high on phenomenological localisation and automaticity/attention, while right-hemisphere colour area responses showed a relationship with localisation

Application of the SP theory of intelligence to the understanding of natural vision and the development of computer vision.

Science.gov (United States)

Wolff, J Gerard

2014-01-01

The SP theory of intelligence aims to simplify and integrate concepts in computing and cognition, with information compression as a unifying theme. This article is about how the SP theory may, with advantage, be applied to the understanding of natural vision and the development of computer vision. Potential benefits include an overall simplification of concepts in a universal framework for knowledge and seamless integration of vision with other sensory modalities and other aspects of intelligence. Low level perceptual features such as edges or corners may be identified by the extraction of redundancy in uniform areas in the manner of the run-length encoding technique for information compression. The concept of multiple alignment in the SP theory may be applied to the recognition of objects, and to scene analysis, with a hierarchy of parts and sub-parts, at multiple levels of abstraction, and with family-resemblance or polythetic categories. The theory has potential for the unsupervised learning of visual objects and classes of objects, and suggests how coherent concepts may be derived from fragments. As in natural vision, both recognition and learning in the SP system are robust in the face of errors of omission, commission and substitution. The theory suggests how, via vision, we may piece together a knowledge of the three-dimensional structure of objects and of our environment, it provides an account of how we may see things that are not objectively present in an image, how we may recognise something despite variations in the size of its retinal image, and how raster graphics and vector graphics may be unified. And it has things to say about the phenomena of lightness constancy and colour constancy, the role of context in recognition, ambiguities in visual perception, and the integration of vision with other senses and other aspects of intelligence.

On the colour contribution to effective weak vertex in broken colour gauge theories

International Nuclear Information System (INIS)

Ramachandran, R.

1979-01-01

Treating the breaking of colour symmetry via the mixing between the colour gluons and weak bosons (a la Rajasekaran and Roy) it is observed that the colour contribution to the effective weak vertex of a quark at zero momentum transfer is zero upto 0(α). (author)

COLOURFUL DIET FOR GOOD HEALTH

OpenAIRE

Vandana Gupta

2017-01-01

We are surrounded by colour and they can affect us profoundly and in ways that we may not have thought of. It is a known fact, that colours can influence your moods, feelings and emotions. Colours influence your actions and how you respond to people, situations and ideas. Apart from the colour of interiors, exteriors, our clothing and other things, the colour of food and beverage products are also extremely important. Green fruits and vegetables support eye health and may help protect against...

Segmenting memory colours

OpenAIRE

Fredembach, Clément; Estrada, Francisco; Süsstrunk, Sabine

2008-01-01

Memory colours refer to the colour of specific image classes that have the essential attribute of being perceived in a consistent manner by human observers. In colour correction or rendering tasks, this consistency implies that they have to be faithfully reproduced; their importance, in that respect, is greater than other regions in an image. Before these regions can be properly addressed, one must in general detect them. There are various schemes and attributes to do so, but the preferred me...

Disruptive colouration and perceptual grouping.

Science.gov (United States)

Espinosa, Irene; Cuthill, Innes C

2014-01-01

Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical 'tricks', collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object's shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory) objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual 'clutter' or background complexity on search.

Disruptive colouration and perceptual grouping.

Directory of Open Access Journals (Sweden)

Irene Espinosa

Full Text Available Camouflage is the primary defence of many animals and includes multiple strategies that interfere with figure-ground segmentation and object recognition. While matching background colours and textures is widespread and conceptually straightforward, less well explored are the optical 'tricks', collectively called disruptive colouration, that exploit perceptual grouping mechanisms. Adjacent high contrast colours create false edges, but this is not sufficient for an object's shape to be broken up; some colours must blend with the background. We test the novel hypothesis that this will be particularly effective when the colour patches on the animal appear to belong to, not merely different background colours, but different background objects. We used computer-based experiments where human participants had to find cryptic targets on artificial backgrounds. Creating what appeared to be bi-coloured foreground objects on bi-coloured backgrounds, we generated colour boundaries that had identical local contrast but either lay within or between (illusory objects. As predicted, error rates for targets matching what appeared to be different background objects were higher than for targets which had otherwise identical local contrast to the background but appeared to belong to single background objects. This provides evidence for disruptive colouration interfering with higher-level feature integration in addition to previously demonstrated low-level effects involving contour detection. In addition, detection was impeded in treatments where targets were on or in close proximity to multiple background colour or tone boundaries. This is consistent with other studies which show a deleterious influence of visual 'clutter' or background complexity on search.

Colour and Organization Studies

DEFF Research Database (Denmark)

Beyes, Timon

2017-01-01

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...

Colour mixing based on daylight

International Nuclear Information System (INIS)

Meyn, Jan-Peter

2008-01-01

Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large region of the colour space can be covered by mixing three primary colours derived from lossless spectral decomposition of daylight. These primaries are specified by hue, saturation and luminosity. Duality of additive and subtractive mixing is formulated quantitatively. Experimental demonstrations of calculated results are suggested. This paper is intended for undergraduate optics courses, and advanced interdisciplinary seminars on arts and physics

Colour As a Signal for Entraining the Mammalian Circadian Clock

Science.gov (United States)

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

2015-01-01

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

Colour Mixing Based on Daylight

Science.gov (United States)

Meyn, Jan-Peter

2008-01-01

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

The twelve colourful stones

International Nuclear Information System (INIS)

Doria, R.M.

1983-01-01

A dynamics with twelve colourful stones is created based on the concepts of gauge and colour. It is associated different gauge fields to the same group. A group of gauge invariant Lagrangians is established. A gauge invariant mass term is introduced. The colourful stones physical insight is to be building blocks for quarks and leptons. (Author) [pt

Optimization of colour quality of LED lighting with reference to memory colours

OpenAIRE

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

2012-01-01

Simulated and real tri- and tetrachromatic light-emitting-diode (LED) clusters were optimized for luminous efficacy of radiation (LER) and the memory colour quality metric developed by the authors. The simulated clusters showed no significant differences in achievable colour quality and LER between the different cluster types investigated. The real clusters (composed of commercially available LEDs) showed substantial differences in achievable colour quality and LER between the different clus...

Colour-scent associations in a tropical orchid: three colours but two odours.

Science.gov (United States)

Delle-Vedove, Roxane; Juillet, Nicolas; Bessière, Jean-Marie; Grison, Claude; Barthes, Nicolas; Pailler, Thierry; Dormont, Laurent; Schatz, Bertrand

2011-06-01

Colour and scent are the major pollinator attractants to flowers, and their production may be linked by shared biosynthetic pathways. Species with polymorphic floral traits are particularly relevant to study the joint evolution of floral traits. We used in this study the tropical orchid Calanthe sylvatica from Réunion Island. Three distinct colour varieties are observed, presenting lilac, white or purple flowers, and named respectively C. sylvaticavar.lilacina (hereafter referred as var. lilacina), C. sylvaticavar. alba (var. alba) and C. sylvatica var. purpurea (var. purpurea). We investigated the composition of the floral scent produced by these colour varieties using the non-invasive SPME technique in the wild. Scent emissions are dominated by aromatic compounds. Nevertheless, the presence of the terpenoid (E)-4,8-dimethylnona-1,3,7-triène (DMNT) is diagnostic of var. purpurea, with the volatile organic compounds (VOC) produced by some individuals containing up to 60% of DMNT. We evidence specific colour-scent associations in C. sylvatica, with two distinct scent profiles in the three colour varieties: the lilacina-like profile containing no or very little DMNT (2%). Calanthe sylvatica var. alba individuals group with one or the other scent profile independently of their population of origin. We suggest that white-flowered individuals have evolved at least twice, once from var. lilacina and at least once from var. purpurea after the colonisation of la Réunion. White-flowered individuals may have been favoured by the particular pollinator fauna characterising the island. These flowering varieties of C. sylvatica, which display three colours but two scents profiles prove that colour is not always a good indicator of odour and that colour-scent associations may be complex, depending on pollination ecology of the populations concerned. Copyright © 2011 Elsevier Ltd. All rights reserved.

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...... 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...... 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...

Estimation of Theaflavins (TF) and Thearubigins (TR) Ratio in Black Tea Liquor Using Electronic Vision System

Science.gov (United States)

Akuli, Amitava; Pal, Abhra; Ghosh, Arunangshu; Bhattacharyya, Nabarun; Bandhopadhyya, Rajib; Tamuly, Pradip; Gogoi, Nagen

2011-09-01

Quality of black tea is generally assessed using organoleptic tests by professional tea tasters. They determine the quality of black tea based on its appearance (in dry condition and during liquor formation), aroma and taste. Variation in the above parameters is actually contributed by a number of chemical compounds like, Theaflavins (TF), Thearubigins (TR), Caffeine, Linalool, Geraniol etc. Among the above, TF and TR are the most important chemical compounds, which actually contribute to the formation of taste, colour and brightness in tea liquor. Estimation of TF and TR in black tea is generally done using a spectrophotometer instrument. But, the analysis technique undergoes a rigorous and time consuming effort for sample preparation; also the operation of costly spectrophotometer requires expert manpower. To overcome above problems an Electronic Vision System based on digital image processing technique has been developed. The system is faster, low cost, repeatable and can estimate the amount of TF and TR ratio for black tea liquor with accuracy. The data analysis is done using Principal Component Analysis (PCA), Multiple Linear Regression (MLR) and Multiple Discriminate Analysis (MDA). A correlation has been established between colour of tea liquor images and TF, TR ratio. This paper describes the newly developed E-Vision system, experimental methods, data analysis algorithms and finally, the performance of the E-Vision System as compared to the results of traditional spectrophotometer.

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.......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....

77 FR 3547 - Qualification of Drivers; Exemption Applications; Vision

Science.gov (United States)

2012-01-24

... restricting him or her to driving in intrastate commerce. To evaluate the effect of these exemptions on safety... the vision deficiency for the past 3 years. Recent driving performance is especially important in evaluating future safety, according to several research studies designed to correlate past and future driving...

77 FR 38379 - Qualification of Drivers; Exemption Applications; Vision

Science.gov (United States)

2012-06-27

... restricting him or her to driving in intrastate commerce. To evaluate the effect of these exemptions on safety... the vision deficiency for the past 3 years. Recent driving performance is especially important in evaluating future safety, according to several research studies designed to correlate past and future driving...

Colour isomers in quark material

International Nuclear Information System (INIS)

Hoegaasen, H.

1981-01-01

Quantum chromodynamics is stated to be analogous to quantum electrodynamics and colour to electric charge. However since there are eight gluon fields and only one photon field, and gluons have colour while photons are electrically neutral, QCD is much more complicated than QED. The concept of colour confine confinement is introduced and the addition rules for colour multiplets are discussed. It is shown that quark colour leads to isomeric meson states. Bubble chamber films from CERN groups have been examined and hyperons and (sup a)Y* resonance particles have been found, which appears to confirm the theory. (JIW)

An evaluation of advanced digital colour technology for colour matching maxillofacial prosthetics.

OpenAIRE

Nacher-Garcia, C.

2016-01-01

Aim: To evaluate the reliability and reproducibility of the Spectromatch-Pro digital colour system (Spectromatch Ltd. UK) in the reproduction of simulated skin-silicone colour samples; and to determine threshold Delta E (∆E) (CIE L*a*b*) of perceptible and acceptable colour differences for maxillofacial prosthetics. Method: A two phase quantitative research design. Phase 1: tested; (i) the reproducibility of the spectrophotometer for eight subjects (n=48) scans; from four ethnic groups...

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...

Biomimetic superwettable materials with structural colours.

Science.gov (United States)

Wang, Zelinlan; Guo, Zhiguang

2017-12-05

Structural colours and superwettability are of great interest due to their unique characteristics. However, the application of materials with either structural colours or superwettability is limited. Moreover, materials possessing both structural colours and superwettability are crucial for many practical applications. The combination of structural colours and superwettability can result in materials for use various applications, such as in sensors, detectors, bioassays, anti-counterfeiting, and liquid actuators, by controlling surfaces to repel or absorb liquids. Regarding superwettability and structural colours, surface texture and chemical composition are two factors for the construction of materials with superwettable structural colours. This review aims at offering a comprehensive elaboration of the mechanism, recent biomimetic research, and applications of biomimetic superwettable materials with structural colours. Furthermore, this review provides significant insight into the design, fabrication, and application of biomimetic superwettable materials with structural colours.

Chemistry of Colours

Indian Academy of Sciences (India)

focus on why things have colour and what causes them to change their colour. Light is a form of .... Another pigment found in the leaves of many plants is carotene. Carotene absorbs ... structure of cyanidin changes with pH. The form shown in ...

Connected Colourings of Complete Graphs and Hypergraphs

OpenAIRE

Leader, Imre; Tan, Ta Sheng

2014-01-01

Gallai's colouring theorem states that if the edges of a complete graph are 3-coloured, with each colour class forming a connected (spanning) subgraph, then there is a triangle that has all 3 colours. What happens for more colours: if we $k$-colour the edges of the complete graph, with each colour class connected, how many of the $\\binom{k}{3}$ triples of colours must appear as triangles? In this note we show that the `obvious' conjecture, namely that there are always at least $\\binom{k-1}{2}...

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

Science.gov (United States)

Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

2009-01-01

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

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…

Colourism: a global adolescent health concern.

Science.gov (United States)

Craddock, Nadia; Dlova, Ncoza; Diedrichs, Phillippa C

2018-05-08

Colourism, a form of prejudice and discrimination based solely upon skin colour, stands to jeopardize the physical health, wellbeing and life chances of adolescents of colour, globally. Research shows that adolescents can experience colourism at school and college, in the criminal justice system, at work and in the media they consume. It is therefore unsurprising that adolescents of colour often express a desire for lighter skin tones and/or are dissatisfied with their skin tone. Although research is scarce, some studies include older adolescents in their samples of skin-lightening product users. This is significant as the evidence is clear that the unmonitored use of skin-lightening products can be harmful to physical and psychological health, with evidence linking skin-lightening use to skin damage, kidney failure and depression. Although it is evident that colourism is central to the lives of adolescents of colour, more research is needed concerning the use of skin-lightening products among adolescents. Media literacy and critical race theory offer avenues in helping attenuate the harmful impact of colourism for adolescents of colour.

Dense Fully Convolutional Segmentation of the Optic Disc and Cup in Colour Fundus for Glaucoma Diagnosis

Directory of Open Access Journals (Sweden)

Baidaa Al-Bander

2018-03-01

Full Text Available Glaucoma is a group of eye diseases which can cause vision loss by damaging the optic nerve. Early glaucoma detection is key to preventing vision loss yet there is a lack of noticeable early symptoms. Colour fundus photography allows the optic disc (OD to be examined to diagnose glaucoma. Typically, this is done by measuring the vertical cup-to-disc ratio (CDR; however, glaucoma is characterised by thinning of the rim asymmetrically in the inferior-superior-temporal-nasal regions in increasing order. Automatic delineation of the OD features has potential to improve glaucoma management by allowing for this asymmetry to be considered in the measurements. Here, we propose a new deep-learning-based method to segment the OD and optic cup (OC. The core of the proposed method is DenseNet with a fully-convolutional network, whose symmetric U-shaped architecture allows pixel-wise classification. The predicted OD and OC boundaries are then used to estimate the CDR on two axes for glaucoma diagnosis. We assess the proposed method’s performance using a large retinal colour fundus dataset, outperforming state-of-the-art segmentation methods. Furthermore, we generalise our method to segment four fundus datasets from different devices without further training, outperforming the state-of-the-art on two and achieving comparable results on the remaining two.

Legal and Illegal Colours

DEFF Research Database (Denmark)

Larsen, John Christian

2008-01-01

opinions on food additives, including colours, and on the bioavailability and safety of nutrient sources. The WG ADD consists of several members from the AFC Panel together with selected external experts. The draft opinions go forward to the AFC Panel for discussion and final adoption. The adopted opinions......://www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178620761956.htm. Accessed 12.05.08.] this paper only deals with some of the major issues that the Panel has faced in relation to the use of food colours. The three topics to be dealt with are (1) evaluation of illegal colours in food in the EU (EFSA, 2005), (2) re-evaluation of the authorised...... food colours in the EU (ongoing, but one opinion on Red 2G has been published; EFSA, 2007), and (3) evaluation of 'the Southampton study' on hyperactivity in children after intake of food colours (and sodium benzoate) (ongoing at the time of this presentation, but an opinion has now been published...

The twelve colourful stones

International Nuclear Information System (INIS)

Doria, R.M.

1984-01-01

The gauge symmetry is extended. It is associated differents matter and gauge fields to the same group. A group of gauge invariant Lagrangians is established. A gauge invariant mass term is introduced. A massive Yang Mills is obtained. A dynamics with twelve colourful stones is created based on the concepts of gauge and colour. Structures identified as quarks and leptons are generated. A discussion about colour meaning is presented. (Author) [pt

Consumer exposures to anthocyanins from colour additives, colouring foodstuffs and from natural occurrence in foods.

Science.gov (United States)

Tennant, David R; Klingenberg, Andreas

2016-06-01

Anthocyanins are responsible for the red/blue colour of grapes, currants, and other fruits and vegetables. They may also be extracted for use as colour additives (E163) or concentrated for use as colouring foods. Consumer exposures have been assessed using data on natural occurrence, use levels and frequencies from food manufacturers and European food consumption data. Intakes from natural occurrence can be up to 4 mg kg bw(-1) day(-1) at the mean and up to 17 mg kg bw(-1) day(-1) for children who are high level consumers of red/black berries and small fruits. High-level intakes for children from food colour and colouring food applications lie in the range 0.3-6.3 mg kg bw(-1) day(-1) and for adults at 0.6-2.8 mg kg bw(-1) day(-1). Exposures from food colour use and colouring foods separately or combined are therefore lower than those from natural occurrence in foods.

The original colours of fossil beetles.

Science.gov (United States)

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

2012-03-22

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

Reproducibility of an objective four-choice canine vision testing technique that assesses vision at differing light intensities.

Science.gov (United States)

Annear, Matthew J; Gornik, Kara R; Venturi, Francesca L; Hauptman, Joe G; Bartoe, Joshua T; Petersen-Jones, Simon M

2013-09-01

The increasing importance of canine retinal dystrophy models means accurate vision testing is needed. This study was performed to evaluate a four-choice vision testing technique for any difference in outcome measures with repeated evaluations of the same dogs.   Four 11-month-old RPE65-deficient dogs. Vision was evaluated using a previously described four-choice vision testing device. Four evaluations were performed at 2-week intervals. Vision was assessed at six different white light intensities (bright through dim), and each eye was evaluated separately. The ability to select the one of the four exit tunnels that was open at the far end was assessed ('choice of exit') and recorded as correct or incorrect first tunnel choice. 'Time to exit' the device was also recorded. Both outcomes were analyzed for significance using anova. We hypothesized that performance would improve with repeated testing (more correct choices and more rapid time to exit). 'Choice of exit' did not vary significantly between each evaluation (P = 0.12), in contrast 'time to exit' increased significantly (P = 0.012), and showed greater variability in dim light conditions. We found no evidence to support the hypothesis that either measure of outcome worsened with repeated testing; in fact, the 'time to exit' outcome worsened rather than improved. The 'choice of exit' gave consistent results between trials. These outcome data indicate the importance of including a choice-based assessment of vision in addition to measurement of device transit time. © 2012 American College of Veterinary Ophthalmologists.

On colour categorization of nature

NARCIS (Netherlands)

Yendrikhovskij, S.N.

1998-01-01

The following research elaborates on some of the 'semantic' and 'algorithmic' aspects of the categorization process for thc colour domain. The structure of colour categories is argued to resemble the structure of Ihe distribution of colours in the perceived world. This distribution can be

77 FR 12361 - Qualification of Drivers; Exemption Applications; Vision

Science.gov (United States)

2012-02-29

... Martin C. Baschab Donald Hooper Gregory Chiropolos Ronnie G. Lynn Malinda N. Parks Mark Smith Stephen C... experience driving a CMV with the vision deficiency: Joshua H. Boatright Domingo V. Perez James F. Blush Dean.... Pinson Wayne L. Green Stephen R. Marshall James A. Fassbender The following 6 applicants were denied for...

Discrepancies between descriptions and illustrations of colours in Congo red-stained amyloid, and explanation of discrepant colours.

Science.gov (United States)

Howie, Alexander J; Owen-Casey, Mared P

2010-09-01

Congo red-stained sections of amyloid may show various colours between crossed polariser and analyser. The aims were to see how papers described the colours, to compare descriptions with illustrations, and to explain the colours. In 160 papers on Congo red-stained amyloid, the commonest descriptions were 'green birefringence' and 'apple-green birefringence'. In 191 figures in 82 papers, 59 (31%) showed a pure green colour, 62 (32%) showed green and yellow or blue and yellow, 38 (20%) showed green and a colour other than yellow, mostly red, and 32 (17%) showed other colours. Discrepancies between colours reported and illustrated were noted in 127 figures (66%). Most (77) were between green alone in descriptions and green and another colour in figures, and 30 were between green in descriptions and no green at all in figures. Pure green can be seen in ideal conditions, but more often there are green and yellow, explained by strain birefringence, and green and red or other combinations, explained by uncrossing of polariser and analyser. These other anomalous colours are just as characteristic of amyloid as the pure green colour. Many papers on Congo red-stained amyloid appear to describe what is expected theoretically rather than what is actually seen.

Influence of colour in working environment

OpenAIRE

Gabrovšek, Barbara

2014-01-01

Anton Trstenjak wrote: »Our life is practically sinking in the sea of light and colours.« Different colours create different psycho-physiological responses. That is why colours have various impacts on human experiences and arrangements of our attention. When we know how control the colours in our environment, we can influence human psychological and physiological well-being and attention in the space. In my thesis, I explore how colours affect our feelings, our body and attention. Knowing all...

Electrophysiological evidence for colour effects on the naming of colour diagnostic and noncolour diagnostic objects

OpenAIRE

Bramão, I.; Francisco, A.; Inácio , F.; Faísca, L.; Reis, A.; Petersson, K.

2012-01-01

In this study, we investigated the level of visual processing at which surface colour information improves the naming of colour diagnostic and noncolour diagnostic objects. Continuous electroencephalograms were recorded while participants performed a visual object naming task in which coloured and black-and-white versions of both types of objects were presented. The black-and-white and the colour presentations were compared in two groups of event-related potentials (ERPs): (1) The P1 and N1 c...

Behavioral impairments in animal models for zinc deficiency

Directory of Open Access Journals (Sweden)

Simone eHagmeyer

2015-01-01

Full Text Available Apart from teratogenic and pathological effects of zinc deficiency such as the occurrence of skin lesions, anorexia, growth retardation, depressed wound healing, altered immune function, impaired night vision, and alterations in taste and smell acuity, characteristic behavioral changes in animal models and human patients suffering from zinc deficiency have been observed. Given that it is estimated that about 17% of the worldwide population are at risk for zinc deficiency and that zinc deficiency is associated with a variety of brain disorders and disease states in humans, it is of major interest to investigate, how these behavioral changes will affect the individual and a putative course of a disease. Thus, here, we provide a state of the art overview about the behavioral phenotypes observed in various models of zinc deficiency, among them environmentally produced zinc deficient animals as well as animal models based on a genetic alteration of a particular zinc homeostasis gene. Finally, we compare the behavioral phenotypes to the human condition of mild to severe zinc deficiency and provide a model, how zinc deficiency that is associated with many neurodegenerative and neuropsychological disorders might modify the disease pathologies.

Vision based nutrient deficiency classification in maize plants using multi class support vector machines

Science.gov (United States)

Leena, N.; Saju, K. K.

2018-04-01

Nutritional deficiencies in plants are a major concern for farmers as it affects productivity and thus profit. The work aims to classify nutritional deficiencies in maize plant in a non-destructive mannerusing image processing and machine learning techniques. The colored images of the leaves are analyzed and classified with multi-class support vector machine (SVM) method. Several images of maize leaves with known deficiencies like nitrogen, phosphorous and potassium (NPK) are used to train the SVM classifier prior to the classification of test images. The results show that the method was able to classify and identify nutritional deficiencies.

Colour correct: the interactive effects of food label nutrition colouring schemes and food category healthiness on health perceptions.

Science.gov (United States)

Nyilasy, Gergely; Lei, Jing; Nagpal, Anish; Tan, Joseph

2016-08-01

The purpose of the present study was to examine the effects of food label nutrition colouring schemes in interaction with food category healthiness on consumers' perceptions of food healthiness. Three streams of colour theory (colour attention, colour association and colour approach-avoidance) in interaction with heuristic processing theory provide consonant predictions and explanations for the underlying psychological processes. A 2 (food category healthiness: healthy v. unhealthy)×3 (food label nutrient colouring schemes: healthy=green, unhealthy=red (HGUR) v. healthy=red, unhealthy=green (HRUG) v. no colour (control)) between-subjects design was used. The research setting was a randomised-controlled experiment using varying formats of food packages and nutritional information colouring. Respondents (n 196) sourced from a national consumer panel, USA. The findings suggest that, for healthy foods, the nutritional colouring schemes reduced perceived healthiness, irrespective of which nutrients were coloured red or green (healthinesscontrol=4·86; healthinessHGUR=4·10; healthinessHRUG=3·70). In contrast, for unhealthy foods, there was no significant difference in perceptions of food healthiness when comparing different colouring schemes against the control. The results make an important qualification to the common belief that colour coding can enhance the correct interpretation of nutrition information and suggest that this incentive may not necessarily support healthier food choices in all situations.

Visual loss and optic nerve head swelling in thiamine deficiency without prolonged dietary deficiency

Directory of Open Access Journals (Sweden)

Gratton SM

2014-05-01

Full Text Available Sean M Gratton, Byron L LamBascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, USAAbstract: Visual loss due to optic neuropathy is a rare manifestation of thiamine deficiency. We report a case of a 39-year-old woman with a body mass index (BMI of 29 kg/m2 who developed visual loss and bilateral optic nerve head swelling after a short, self-limited gastrointestinal illness. She was disoriented and inattentive and had absent ankle jerk reflexes, diminished sensation in both legs below the knees, and marked truncal ataxia. Magnetic resonance imaging (MRI showed increased T2-signal in the medial thalami and mammillary bodies. The serum thiamine level was 8 nmol/L (normal 8–30. The diagnosis of thiamine deficiency was made, and the patient’s vision and neurologic symptoms improved significantly with intramuscular thiamine treatment. Thiamine deficiency can occur in the absence of an obvious predisposing factor such as alcoholism or low body weight. The clinician must be aware of the factors that govern vitamin availability and maintain a high index of suspicion to make the diagnosis in such cases.Keywords: optic neuropathy, nutritional deficiency

The control of attentional target selection in a colour/colour conjunction task.

Science.gov (United States)

Berggren, Nick; Eimer, Martin

2016-11-01

To investigate the time course of attentional object selection processes in visual search tasks where targets are defined by a combination of features from the same dimension, we measured the N2pc component as an electrophysiological marker of attentional object selection during colour/colour conjunction search. In Experiment 1, participants searched for targets defined by a combination of two colours, while ignoring distractor objects that matched only one of these colours. Reliable N2pc components were triggered by targets and also by partially matching distractors, even when these distractors were accompanied by a target in the same display. The target N2pc was initially equal in size to the sum of the two N2pc components to the two different types of partially matching distractors and became superadditive from approximately 250 ms after search display onset. Experiment 2 demonstrated that the superadditivity of the target N2pc was not due to a selective disengagement of attention from task-irrelevant partially matching distractors. These results indicate that attention was initially deployed separately and in parallel to all target-matching colours, before attentional allocation processes became sensitive to the presence of both matching colours within the same object. They suggest that attention can be controlled simultaneously and independently by multiple features from the same dimension and that feature-guided attentional selection processes operate in parallel for different target-matching objects in the visual field.

Anisometropia and ptosis in patients with monocular elevation deficiency

International Nuclear Information System (INIS)

Zafar, S.N.; Islam, F.; Khan, A.M.

2016-01-01

Objective: To determine the effect of ptosis on the refractive error in eyes having monocular elevation deficiency Place and Duration of Study: Al-Shifa Trust Eye Hospital, Rawalpindi, from January 2011 to January 2014. Methodology: Visual acuity, refraction, orthoptic assessment and ptosis evaluation of all patients having monocular elevation deficiency (MED) were recorded. Shapiro-Wilk test was used for tests of normality. Median and interquartile range (IQR) was calculated for the data. Non-parametric variables were compared, using the Wilcoxon signed ranks test. P-values of <0.05 were considered significant. Results: A total of of 41 MED patients were assessed during the study period. Best corrected visual acuity (BCVA) and refractive error was compared between the eyes having MED and the unaffected eyes of the same patient. The refractive status of patients having ptosis with MED were also compared with those having MED without ptosis. Astigmatic correction and vision had significant difference between both the eyes of the patients. Vision was significantly different between the two eyes of patients in both the groups having either presence or absence of ptosis (p=0.04 and p < 0.001, respectively). Conclusion: Significant difference in vision and anisoastigmatism was noted between the two eyes of patients with MED in this study. The presence or absence of ptosis affected the vision but did not have a significant effect on the spherical equivalent (SE) and astigmatic correction between both the eyes. (author)

The brightness of colour.

Directory of Open Access Journals (Sweden)

David Corney

Full Text Available 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.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.The data suggest that perceptions of brightness represent a robust

Colour-rendition properties of solid-state lamps

Energy Technology Data Exchange (ETDEWEB)

Zukauskas, A [Institute of Applied Research, Vilnius University, Sauletekio al. 9, bldg. III, Vilnius, LT-10222 (Lithuania); Vaicekauskas, R [Department of Computer Science, Vilnius University, Naugarduko g. 24, Vilnius, LT-03225 (Lithuania); Shur, M S, E-mail: arturas.zukauskas@ff.vu.l [Department of Electrical, Computer, and System Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 (United States)

2010-09-08

The applicability of colour-quality metrics to solid-state light sources is validated and the results of the assessment of colour-rendition characteristics of various lamps are presented. The standard colour-rendering index metric or a refined colour-quality scale metric fails to distinguish between two principle colour-rendition properties of illumination: the ability to render object colours with high fidelity and the ability to increase chromatic contrast, especially when the spectra of light sources contain a few narrow-band electroluminescence components. Supplementing these metrics by the known figures of merit that measure the gamut area of a small number of test colour samples does not completely resolve this issue. In contrast, the statistical approach, which is based on sorting a very large number of test colour samples in respect of just-perceivable colour distortions of several kinds, offers a comprehensive assessment of colour-rendition properties of solid-state light sources. In particular, two statistical indices, colour-fidelity index (CFI) and colour-saturation index (CSI), which are the relative numbers of object colours rendered with high fidelity and increased saturation, respectively, are sufficient to reveal and assess three distinct types of solid-state light sources. These are (i) high-fidelity lamps, which cover the entire spectrum with the spectral components present in the wavelength ranges of both 530-610 nm and beyond 610 nm (e.g. trichromatic warm white phosphor-converted (pc) light-emitting diodes (LEDs), red-amber-green-blue LED clusters, complementary clusters of white and coloured LEDs); (ii) colour-saturating lamps, which lack power in the 530-610 nm wavelength range (e.g. red-green-blue or red-cyan-blue LED clusters) and (iii) colour-dulling lamps, which lack power for wavelengths longer than 610 nm (dichromatic daylight pc LEDs and amber-green-blue LED clusters). Owing to a single statistical format, CSI and CFI can be used for

Colour-rendition properties of solid-state lamps

International Nuclear Information System (INIS)

Zukauskas, A; Vaicekauskas, R; Shur, M S

2010-01-01

The applicability of colour-quality metrics to solid-state light sources is validated and the results of the assessment of colour-rendition characteristics of various lamps are presented. The standard colour-rendering index metric or a refined colour-quality scale metric fails to distinguish between two principle colour-rendition properties of illumination: the ability to render object colours with high fidelity and the ability to increase chromatic contrast, especially when the spectra of light sources contain a few narrow-band electroluminescence components. Supplementing these metrics by the known figures of merit that measure the gamut area of a small number of test colour samples does not completely resolve this issue. In contrast, the statistical approach, which is based on sorting a very large number of test colour samples in respect of just-perceivable colour distortions of several kinds, offers a comprehensive assessment of colour-rendition properties of solid-state light sources. In particular, two statistical indices, colour-fidelity index (CFI) and colour-saturation index (CSI), which are the relative numbers of object colours rendered with high fidelity and increased saturation, respectively, are sufficient to reveal and assess three distinct types of solid-state light sources. These are (i) high-fidelity lamps, which cover the entire spectrum with the spectral components present in the wavelength ranges of both 530-610 nm and beyond 610 nm (e.g. trichromatic warm white phosphor-converted (pc) light-emitting diodes (LEDs), red-amber-green-blue LED clusters, complementary clusters of white and coloured LEDs); (ii) colour-saturating lamps, which lack power in the 530-610 nm wavelength range (e.g. red-green-blue or red-cyan-blue LED clusters) and (iii) colour-dulling lamps, which lack power for wavelengths longer than 610 nm (dichromatic daylight pc LEDs and amber-green-blue LED clusters). Owing to a single statistical format, CSI and CFI can be used for

Colour revolutions: criminal-legal aspect

Directory of Open Access Journals (Sweden)

Sergey Alekseyevich Gordeychik

2015-03-01

Full Text Available Objective basing on the analysis of colour revolution technologies in different countries to formulate propositions for improving criminal legislation aimed at counteraction against this phenomenon. Methods general scientific induction deduction analysis synthesis and specific scientific formaljuridical and comparativelegal. Results using the results of colour revolutionsrsquo research carried out by political scientists the author evaluates the character and level of public danger of colour revolutions. The author states that the colour revolutions threaten the normal existence of the country or several countries. The conclusion is made that the colour revolutions must be counteracted by criminallegal means. The article states the absence of norms in the existing criminal legislation which would impose criminal liability on organizers incendiaries and participants of colour revolutions. It is proposed to supplement the existing criminal law with the norm stipulating the liability for such deeds and to insert this norm into Art. 34 ldquoCrimes against peace and security of humanityrdquo thus equating organization preparation and implementing colour revolutions with planning preparation launching and conducting an aggressive war Art. 353 of the Russian Criminal Code. Scientific novelty basing on the existing legal norms modern politological and juridical scientific literature a conclusion is made that the colour revolutions are based on the abuse of law. This allows the organizers of colour revolutions to legally prepare and implement the subversion of undesirable political regimes. The author formulates proposals for supplementing the criminal legislation. Practical value the materials and conclusions of the article can be used in lawmaking activity when elaborating the drafts of legal acts for changing and supplementing the Russian Criminal Code for research activity when preparing monographs and dissertations tutorials and articles when

Evidence for RPE65-independent vision in the cone-dominated zebrafish retina.

Science.gov (United States)

Schonthaler, Helia B; Lampert, Johanna M; Isken, Andrea; Rinner, Oliver; Mader, Andreas; Gesemann, Matthias; Oberhauser, Vitus; Golczak, Marcin; Biehlmaier, Oliver; Palczewski, Krzysztof; Neuhauss, Stephan C F; von Lintig, Johannes

2007-10-01

An enzyme-based cyclic pathway for trans to cis isomerization of the chromophore of visual pigments (11-cis-retinal) is intrinsic to vertebrate cone and rod vision. This process, called the visual cycle, is mostly characterized in rod-dominated retinas and essentially depends on RPE65, an all-trans to 11-cis-retinoid isomerase. Here we analysed the role of RPE65 in zebrafish, a species with a cone-dominated retina. We cloned zebrafish RPE65 and showed that its expression coincided with photoreceptor development. Targeted gene knockdown of RPE65 resulted in morphologically altered rod outer segments and overall reduced 11-cis-retinal levels. Cone vision of RPE65-deficient larvae remained functional as demonstrated by behavioural tests and by metabolite profiling for retinoids. Furthermore, all-trans retinylamine, a potent inhibitor of the rod visual cycle, reduced 11-cis-retinal levels of control larvae to a similar extent but showed no additive effects in RPE65-deficient larvae. Thus, our study of zebrafish provides in vivo evidence for the existence of an RPE65-independent pathway for the regeneration of 11-cis-retinal for cone vision.

Colour Day: an innovative project

CERN Multimedia

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...

Block colourings of 6-cycle systems

Directory of Open Access Journals (Sweden)

Paola Bonacini

2017-01-01

Full Text Available Let \\(\\Sigma=(X,\\mathcal{B}\\ be a \\(6\\-cycle system of order \\(v\\, so \\(v\\equiv 1,9\\mod 12\\. A \\(c\\-colouring of type \\(s\\ is a map \\(\\phi\\colon\\mathcal {B}\\rightarrow \\mathcal{C}\\, with \\(C\\ set of colours, such that exactly \\(c\\ colours are used and for every vertex \\(x\\ all the blocks containing \\(x\\ are coloured exactly with \\(s\\ colours. Let \\(\\frac{v-1}{2}=qs+r\\, with \\(q, r\\geq 0\\. \\(\\phi\\ is equitable if for every vertex \\(x\\ the set of the \\(\\frac{v-1}{2}\\ blocks containing \\(x\\ is partitioned in \\(r\\ colour classes of cardinality \\(q+1\\ and \\(s-r\\ colour classes of cardinality \\(q\\. In this paper we study bicolourings and tricolourings, for which, respectively, \\(s=2\\ and \\(s=3\\, distinguishing the cases \\(v=12k+1\\ and \\(v=12k+9\\. In particular, we settle completely the case of \\(s=2\\, while for \\(s=3\\ we determine upper and lower bounds for \\(c\\.

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.

Skin Colour Analysis of Iraqi Kurdish Population

OpenAIRE

Zardawi, Faraedon M; Xiao, Kaida; Yates, Julian M

2015-01-01

Objective: Skin colour measurement and analysis was performed for Iraqi Kurdish population in sulaimani city. The purpose of this study was to produce a dedicated skin shade guide for precise colour reproduction and colour matching of maxillofacial prostheses with the patient’s original skin colour. Methodology: A skin colour measurement was undertaken for 140 subjects (73 female and 67 male). A method of capturing their (L* a* b*) colour values from nine body parts was performed using a Mi...

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...

Synaesthetic colour in the brain: beyond colour areas. A functional magnetic resonance imaging study of synaesthetes and matched controls.

Science.gov (United States)

van Leeuwen, Tessa M; Petersson, Karl Magnus; Hagoort, Peter

2010-08-10

In synaesthesia, sensations in a particular modality cause additional experiences in a second, unstimulated modality (e.g., letters elicit colour). Understanding how synaesthesia is mediated in the brain can help to understand normal processes of perceptual awareness and multisensory integration. In several neuroimaging studies, enhanced brain activity for grapheme-colour synaesthesia has been found in ventral-occipital areas that are also involved in real colour processing. Our question was whether the neural correlates of synaesthetically induced colour and real colour experience are truly shared. First, in a free viewing functional magnetic resonance imaging (fMRI) experiment, we located main effects of synaesthesia in left superior parietal lobule and in colour related areas. In the left superior parietal lobe, individual differences between synaesthetes (projector-associator distinction) also influenced brain activity, confirming the importance of the left superior parietal lobe for synaesthesia. Next, we applied a repetition suppression paradigm in fMRI, in which a decrease in the BOLD (blood-oxygenated-level-dependent) response is generally observed for repeated stimuli. We hypothesized that synaesthetically induced colours would lead to a reduction in BOLD response for subsequently presented real colours, if the neural correlates were overlapping. We did find BOLD suppression effects induced by synaesthesia, but not within the colour areas. Because synaesthetically induced colours were not able to suppress BOLD effects for real colour, we conclude that the neural correlates of synaesthetic colour experience and real colour experience are not fully shared. We propose that synaesthetic colour experiences are mediated by higher-order visual pathways that lie beyond the scope of classical, ventral-occipital visual areas. Feedback from these areas, in which the left parietal cortex is likely to play an important role, may induce V4 activation and the percept of

Synaesthetic colour in the brain: beyond colour areas. A functional magnetic resonance imaging study of synaesthetes and matched controls.

Directory of Open Access Journals (Sweden)

Tessa M van Leeuwen

Full Text Available BACKGROUND: In synaesthesia, sensations in a particular modality cause additional experiences in a second, unstimulated modality (e.g., letters elicit colour. Understanding how synaesthesia is mediated in the brain can help to understand normal processes of perceptual awareness and multisensory integration. In several neuroimaging studies, enhanced brain activity for grapheme-colour synaesthesia has been found in ventral-occipital areas that are also involved in real colour processing. Our question was whether the neural correlates of synaesthetically induced colour and real colour experience are truly shared. METHODOLOGY/PRINCIPAL FINDINGS: First, in a free viewing functional magnetic resonance imaging (fMRI experiment, we located main effects of synaesthesia in left superior parietal lobule and in colour related areas. In the left superior parietal lobe, individual differences between synaesthetes (projector-associator distinction also influenced brain activity, confirming the importance of the left superior parietal lobe for synaesthesia. Next, we applied a repetition suppression paradigm in fMRI, in which a decrease in the BOLD (blood-oxygenated-level-dependent response is generally observed for repeated stimuli. We hypothesized that synaesthetically induced colours would lead to a reduction in BOLD response for subsequently presented real colours, if the neural correlates were overlapping. We did find BOLD suppression effects induced by synaesthesia, but not within the colour areas. CONCLUSIONS/SIGNIFICANCE: Because synaesthetically induced colours were not able to suppress BOLD effects for real colour, we conclude that the neural correlates of synaesthetic colour experience and real colour experience are not fully shared. We propose that synaesthetic colour experiences are mediated by higher-order visual pathways that lie beyond the scope of classical, ventral-occipital visual areas. Feedback from these areas, in which the left parietal

Colour preferences in nest-building zebra finches.

Science.gov (United States)

Muth, Felicity; Steele, Matthew; Healy, Susan D

2013-10-01

Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. Copyright © 2013 Elsevier B.V. All rights reserved.

Bio deterioration behaviour in different colour roofing tiles (red and straw coloured)

International Nuclear Information System (INIS)

Guzulla, M. F.; Sanchez, E.; Gonzalez, J. M.; Orduna, M.

2014-01-01

Bio colonization of building materials is a critical problem for the durability of constructions. Industrial experience shows that straw coloured roofing tiles are more prone to colonization than red roofing tiles, even having similar characteristics. The aim of this work is to explain the difference of bio colonization between different colour roofing tiles. The chemical composition of the surface of straw coloured and red roofing tiles, the phase composition and the microstructure of the roofing tiles were determined by WD-XRF, XRD and SEM-EDX, respectively. The pore size distribution was carried out by Hg porosimetry. The solubility was studied by determining the soluble salts (Ca, Mg, Na, K, Cl and SO 4 2-) by ICP-OES and ionic chromatography. Roofing tile bio receptivity was evaluated by determining fluorescence intensity using a pulse amplitude- modulated (PAM) fluoro meter, and cyanobacteria Oscillator sp. The results obtained show higher concentration of calcium and sulphur in straw coloured roofing tiles surface, and higher solubility than red roofing tiles. Moreover, according to the results obtained in bio receptivity assays, straw coloured roofing tiles are more prone to colonization than red roofing tiles, so, there is a relationship between surface properties of roofing tiles and bio colonization, as it is observed in industrial products. (Author)

The Metric of Colour Space

DEFF Research Database (Denmark)

Gravesen, Jens

2015-01-01

and found the MacAdam ellipses which are often interpreted as defining the metric tensor at their centres. An important question is whether it is possible to define colour coordinates such that the Euclidean distance in these coordinates correspond to human perception. Using cubic splines to represent......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...

Colour pyrometer. Farbpyrometer

Energy Technology Data Exchange (ETDEWEB)

Luhleich, H; Suetterlin, L; Borchers, D; Pflaum, P

1980-12-11

The colour pyrometer according to the invention, in which two beams of limited wavelength from the incoming beam of light are filtered through a chopper with two colour filters of the same diameter rotating round and axis, and are taken to a photo-electric element, from the output signals of which a quotient proportional to the surface temperature of the object is formed in an electrical network, is characterized by the fact that the colour filters in the cylinder wall are arranged at a right angle to each other in a drum rotating around the cylinder axis transverse to the incoming light beam, and are parallel to the axis of rotation, and that the drum wall has openings in the sides diametrically opposite the filters.

Attentional capture by masked colour singletons.

Science.gov (United States)

Ansorge, Ulrich; Horstmann, Gernot; Worschech, Franziska

2010-09-15

We tested under which conditions a colour singleton of which an observer is unaware captures attention. To prevent visual awareness of the colour singleton, we used backward masking. We find that a masked colour singleton cue captures attention if it matches the observer's goal to search for target colours but not if it is task-irrelevant. This is also reflected in event-related potentials to the visible target: the masked goal-matching cue elicits an attentional potential (N2pc) in a target search task. By contrast, a non-matching but equally strong masked colour singleton cue failed to elicit a capture effect and an N2pc. Results are discussed with regard to currently pertaining conceptions of attentional capture by colour singletons. Copyright 2010 Elsevier Ltd. All rights reserved.

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...... 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...

An unconventional colour superconductor

International Nuclear Information System (INIS)

Huang Mei

2007-01-01

Superfluidity, or superconductivity with mismatched Fermi momenta, appears in many systems such as charge-neutral dense quark matter, asymmetric nuclear matter, and in imbalanced cold atomic gases. The mismatch plays the role of breaking the Cooper pairing, and the pair-breaking state cannot be properly described in the framework of standard BCS theory. I give a brief review on recent theoretical developments in understanding unconventional colour superconductivity, including a gapless colour superconductor, chromomagnetic instabilities and the Higgs instability in the gapless phase. I also introduce a possible new framework for describing an unconventional colour superconductor

What triggers colour change? Effects of background colour and temperature on the development of an alpine grasshopper.

Science.gov (United States)

Valverde, J Pablo; Schielzeth, Holger

2015-08-21

Colour polymorphisms are a fascinating facet of many natural populations of plants and animals, and the selective processes that maintain such variation are as relevant as the processes which promote their development. Orthoptera, the insect group that encompasses grasshoppers and bush crickets, includes a particularly large number of species that are colour polymorphic with a marked green-brown polymorphism being particularly widespread. Colour polymorphism has been associated with the need for crypsis and background matching and background-dependent homochromy has been described in a few species. However, when and how different environmental conditions influence variation in colour remains poorly understood. Here we test for effects of background colour and ambient temperature on the occurrence of colour morph switches (green to brown or brown to green) and developmental darkening in the alpine dwelling club-legged grasshopper Gomphocerus sibiricus. We monitored individually housed nymphae across three of their four developmental stages and into the first week after final ecdysis. Our data show an absence of colour morph switches in G. sibiricus, without a single switch observed in our sample. Furthermore, we test for an effect of temperature on colouration by manipulating radiant heat, a limiting factor in alpine habitats. Radiant heat had a significant effect on developmental darkening: individuals under low radiant heat tended to darken, while individuals under high radiant heat tended to lighten within nymphal stages. Young imagoes darkened under either condition. Our results indicate a plastic response to a variable temperature and indicate that melanin, a multipurpose pigment responsible for dark colouration and presumed to be costly, seems to be strategically allocated according to the current environmental conditions. Unlike other orthopterans, the species is apparently unable to switch colour morphs (green/brown) during development, suggesting that

Determinants of Colour Constancy and the Blue Bias

Science.gov (United States)

Gegenfurtner, Karl

2017-01-01

We investigated several sensory and cognitive determinants of colour constancy across 40 illumination hues. In the first experiment, we measured colour naming for the illumination and for the colour induced by the illumination on the colorimetric grey. Results confirmed that the induced colours are approximately complementary to the colour of the illumination. In the second experiment, we measured colour constancy using achromatic adjustments. Average colour constancy was perfect under the blue daylight illumination and decreased in colour directions away from the blue daylight illumination due to undershooting and a strong blue bias. Apart from this blue bias, colour constancy was not related to illumination discrimination and to chromatic detection measured previously with the same setup and stimuli. We also observed a strong negative relationship between the degree of colour constancy and the consensus of naming the illumination colour. Constancy coincided with a low naming consensus, in particular because bluish illumination colours were sometimes seen as achromatic. Blue bias and category consensus alone explained >68%, and all determinants together explained >94% of the variance of achromatic adjustments. These findings suggest that colour constancy is optimised for blue daylight. PMID:29348910

Interactions between colour-producing mechanisms and their effects on the integumentary colour palette.

Science.gov (United States)

Shawkey, Matthew D; D'Alba, Liliana

2017-07-05

Animal integumentary coloration plays a crucial role in visual communication and camouflage, and varies extensively among and within species and populations. To understand the pressures underlying such diversity, it is essential to elucidate the mechanisms by which animals have created novel integumentary coloration. Colours can be produced by selective absorption of light by skin pigments, through light scattering by structured or unstructured tissues, or by a combination of pigments and nanostructures. In this review, we highlight our current understanding of the interactions between pigments and structural integumentary tissues and molecules. We analyse the available evidence suggesting that these combined mechanisms are capable of creating colours and optical properties unachievable by either mechanism alone, thereby effectively expanding the animal colour palette. Moreover, structural and pigmentary colour mechanisms frequently interact in unexpected and overlooked ways, suggesting that classification of colours as being of any particular type may be difficult. Finally, we discuss how these mixtures are useful for investigating the largely unknown genetic, developmental and physical processes generating phenotypic diversity.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

Conspicuous plumage colours are highly variable.

Science.gov (United States)

Delhey, Kaspar; Szecsenyi, Beatrice; Nakagawa, Shinichi; Peters, Anne

2017-01-25

Elaborate ornamental traits are often under directional selection for greater elaboration, which in theory should deplete underlying genetic variation. Despite this, many ornamental traits appear to remain highly variable and how this essential variation is maintained is a key question in evolutionary biology. One way to address this question is to compare differences in intraspecific variability across different types of traits to determine whether high levels of variation are associated with specific trait characteristics. Here we assess intraspecific variation in more than 100 plumage colours across 55 bird species to test whether colour variability is linked to their level of elaboration (indicated by degree of sexual dichromatism and conspicuousness) or their condition dependence (indicated by mechanism of colour production). Conspicuous colours had the highest levels of variation and conspicuousness was the strongest predictor of variability, with high explanatory power. After accounting for this, there were no significant effects of sexual dichromatism or mechanisms of colour production. Conspicuous colours may entail higher production costs or may be more sensitive to disruptions during production. Alternatively, high variability could also be related to increased perceptual difficulties inherent to discriminating highly elaborate colours. Such psychophysical effects may constrain the exaggeration of animal colours. © 2017 The Author(s).

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

Vitamin D deficiency intensifies deterioration of risk factors, such as male sex and absence of vision, leading to increased postural body sway.

Science.gov (United States)

Krause, Matthias; Anschütz, Wilma; Vettorazzi, Eik; Breer, Stefan; Amling, Michael; Barvencik, Florian

2014-01-01

Due to inconsistent findings, the influence of vitamin D on postural body sway (PBS) is currently under debate. This study evaluated the impact of vitamin D on PBS with regards to different foot positions and eye opening states in community-dwelling older individuals. In a cross-sectional study, we assessed PBS in 342 older individuals (264 females [average age (± SD): 68.3 ± 9.0 years], 78 males [65.7 ± 9.6 years]). A detailed medical history and vitamin D level were obtained for each individual. Fall risk was evaluated using the New York-Presbyterian Fall Risk Assessment Tool (NY PFRA). PBS parameters (area, distance, velocity, frequency) were evaluated on a pressure plate with feet in closed stance (CS) or hip-width stance (HWS), open eyes and closed eyes. Statistical analysis included logarithmic mixed models for repeated measures with the MIXED model procedure to test the influence of vitamin D (categorized in 30 μg/l), foot position, eye opening state, age, sex and frequency of physical activity on PBS. Vitamin D was not an independent risk factor for falls experienced in the last 12 months. Nonetheless, PBS was higher in patients with vitamin D deficiency (risk factors for increased PBS like male sex and absence of vision are additionally compromised by vitamin D deficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of Pigment Colouring on Physico-mechanical Properties of Hardened Cement Paste and Response of Colour Intensity to UV Radiation

International Nuclear Information System (INIS)

Khattab, M.M.; Abdel-Rahman, H.A.; Hassan, M.S.

2010-01-01

In this work, different ratios of pigment colour was mixed with cement paste during mixing. The pigment colour used was Phthalocyanine Green. The effect of pigment colouring on hardened cement paste (HCP) was characterized in terms of compressive strength, IR spectroscopic analysis and X-ray diffraction. In addition, the effect of UV radiation on the colour strength of hardened cement paste/pigment colour composites was investigated. The results indicated that the increase in the ratio of pigment colour was accompanied with a slight decrease in the values of compressive strength. The exposure of the coloured hardened cement paste to UV radiation for long lengths of time causes a little effect on the colour intensity

IRIS COLOUR CLASSIFICATION SCALES--THEN AND NOW.

Science.gov (United States)

Grigore, Mariana; Avram, Alina

2015-01-01

Eye colour is one of the most obvious phenotypic traits of an individual. Since the first documented classification scale developed in 1843, there have been numerous attempts to classify the iris colour. In the past centuries, iris colour classification scales has had various colour categories and mostly relied on comparison of an individual's eye with painted glass eyes. Once photography techniques were refined, standard iris photographs replaced painted eyes, but this did not solve the problem of painted/ printed colour variability in time. Early clinical scales were easy to use, but lacked objectivity and were not standardised or statistically tested for reproducibility. The era of automated iris colour classification systems came with the technological development. Spectrophotometry, digital analysis of high-resolution iris images, hyper spectral analysis of the human real iris and the dedicated iris colour analysis software, all accomplished an objective, accurate iris colour classification, but are quite expensive and limited in use to research environment. Iris colour classification systems evolved continuously due to their use in a wide range of studies, especially in the fields of anthropology, epidemiology and genetics. Despite the wide range of the existing scales, up until present there has been no generally accepted iris colour classification scale.

Independent effects of colour on object identification and memory.

Science.gov (United States)

Lloyd-Jones, Toby J; Nakabayashi, Kazuyo

2009-02-01

We examined the effects of colour on object identification and memory using a study-test priming procedure with a coloured-object decision task at test (i.e., deciding whether an object is correctly coloured). Objects were selected to have a single associated colour and were either correctly or incorrectly coloured. In addition, object shape and colour were either spatially integrated (i.e., colour fell on the object surface) or spatially separated (i.e., colour formed the background to the object). Transforming the colour of an object from study to test (e.g., from a yellow banana to a purple banana) reduced priming of response times, as compared to when the object was untransformed. This utilization of colour information in object memory was not contingent upon colour falling on the object surface or whether the resulting configuration was of a correctly or incorrectly coloured object. In addition, we observed independent effects of colour on response times, whereby coloured-object decisions were more efficient for correctly than for incorrectly coloured objects but only when colour fell on the object surface. These findings provide evidence for two distinct mechanisms of shape-colour binding in object processing.

Relationship between upper extremity kinesthetic sense and writing performance by students with low vision.

Science.gov (United States)

Aki, Esra; Atasavun, Songül; Kayihan, Holya

2008-06-01

Kinesthetic sense plays an important role in writing. Children with low vision lack sensory input from the environment given their loss of vision. This study assessed the effect of upper extremity kinesthetic sense on writing function in two groups, one of students with low vision (9 girls and 11 boys, 9.4 +/- 1.9 yr. of age) and one of sighted students (10 girls and 10 boys, 10.1 +/- 1.3 yr. of age). All participants were given the Kinesthesia Test and Jebsen Hand Function Test-Writing subtest. Students with low vision scored lower on kinesthetic perception and writing performance than sighted peers. The correlation between scores for writing performance and upper extremity kinesthetic sense in the two groups was significant (r = -.34). The probability of deficiencies in kinesthetic information in students with low vision must be remembered.

Scalable, full-colour and controllable chromotropic plasmonic printing

Science.gov (United States)

Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

2015-01-01

Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates controllable chromotropic capability, that is, the ability of reversible colour transformations. This chromotropic capability affords enormous potentials in building functionalized prints for anticounterfeiting, special label, and high-density data encryption storage. With such excellent performances in functional colour applications, this colour-printing approach could pave the way for plasmonic colour printing in real-world commercial utilization. PMID:26567803

Grapheme-colour synaesthesia improves detection of embedded shapes, but without pre-attentive 'pop-out' of synaesthetic colour.

Science.gov (United States)

Ward, Jamie; Jonas, Clare; Dienes, Zoltan; Seth, Anil

2010-04-07

For people with synaesthesia letters and numbers may evoke experiences of colour. It has been previously demonstrated that these synaesthetes may be better at detecting a triangle made of 2s among a background of 5s if they perceive 5 and 2 as having different synaesthetic colours. However, other studies using this task (or tasks based on the same principle) have failed to replicate the effect or have suggested alternative explanations of the effect. In this study, we repeat the original study on a larger group of synaesthetes (n = 36) and include, for the first time, an assessment of their self-reported colour experiences. We show that synaesthetes do have a general advantage over controls on this task. However, many synaesthetes report no colour experiences at all during the task. Synaesthetes who do report colour typically experience around one third of the graphemes in the display as coloured. This is more consistent with theories of synaesthesia in which spatial attention needs to be deployed to graphemes for conscious colour experiences to emerge than the interpretation based on 'pop-out'.

Ultraviolet vision in lacertid lizards: evidence from retinal structure, eye transmittance, SWS1 visual pigment genes and behaviour.

Science.gov (United States)

Pérez i de Lanuza, Guillem; Font, Enrique

2014-08-15

Ultraviolet (UV) vision and UV colour patches have been reported in a wide range of taxa and are increasingly appreciated as an integral part of vertebrate visual perception and communication systems. Previous studies with Lacertidae, a lizard family with diverse and complex coloration, have revealed the existence of UV-reflecting patches that may function as social signals. However, confirmation of the signalling role of UV coloration requires demonstrating that the lizards are capable of vision in the UV waveband. Here we use a multidisciplinary approach to characterize the visual sensitivity of a diverse sample of lacertid species. Spectral transmission measurements of the ocular media show that wavelengths down to 300 nm are transmitted in all the species sampled. Four retinal oil droplet types can be identified in the lacertid retina. Two types are pigmented and two are colourless. Fluorescence microscopy reveals that a type of colourless droplet is UV-transmitting and may thus be associated with UV-sensitive cones. DNA sequencing shows that lacertids have a functional SWS1 opsin, very similar at 13 critical sites to that in the presumed ancestral vertebrate (which was UV sensitive) and other UV-sensitive lizards. Finally, males of Podarcis muralis are capable of discriminating between two views of the same stimulus that differ only in the presence/absence of UV radiance. Taken together, these results provide convergent evidence of UV vision in lacertids, very likely by means of an independent photopigment. Moreover, the presence of four oil droplet types suggests that lacertids have a four-cone colour vision system. © 2014. Published by The Company of Biologists Ltd.

n-Colour even self-inverse compositions

Indian Academy of Sciences (India)

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.

A Bayesian Model of the Memory Colour Effect.

Science.gov (United States)

Witzel, Christoph; Olkkonen, Maria; Gegenfurtner, Karl R

2018-01-01

According to the memory colour effect, the colour of a colour-diagnostic object is not perceived independently of the object itself. Instead, it has been shown through an achromatic adjustment method that colour-diagnostic objects still appear slightly in their typical colour, even when they are colourimetrically grey. Bayesian models provide a promising approach to capture the effect of prior knowledge on colour perception and to link these effects to more general effects of cue integration. Here, we model memory colour effects using prior knowledge about typical colours as priors for the grey adjustments in a Bayesian model. This simple model does not involve any fitting of free parameters. The Bayesian model roughly captured the magnitude of the measured memory colour effect for photographs of objects. To some extent, the model predicted observed differences in memory colour effects across objects. The model could not account for the differences in memory colour effects across different levels of realism in the object images. The Bayesian model provides a particularly simple account of memory colour effects, capturing some of the multiple sources of variation of these effects.

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...

Thirteen-colour photometry of Be stars

Energy Technology Data Exchange (ETDEWEB)

Alvarez, M; Schuster, W J [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

1981-01-01

Thirteen-colour photometry made at the San Pedro Martir Observatory in Baja California, for a number of spectroscopically variable Be and shell stars is presented. Several of these stars also show photometric variability in the ultraviolet and/or infrared over a time base of two to three years. We analyze the more interesting stars in terms of colour-colour diagrams, colour excesses, spectral characteristics and changes in their energy distributions. Prospects for future research are discussed.

Thirteen-colour photometry of Be stars

International Nuclear Information System (INIS)

Alvarez, M.; Schuster, W.J.

1981-01-01

Thirteen-colour photometry made at the San Pedro Martir Observatory in Baja California, for a number of spectroscopically variable Be and shell stars is presented. Several of these stars also show photometric variability in the ultraviolet and/or infrared over a time base of two to three years. We analyze the more interesting stars in terms of colour-colour diagrams, colour excesses, spectral characteristics and changes in their energy distributions. Prospects for future research are discussed. (author)

CRALBP supports the mammalian retinal visual cycle and cone vision.

Science.gov (United States)

Xue, Yunlu; Shen, Susan Q; Jui, Jonathan; Rupp, Alan C; Byrne, Leah C; Hattar, Samer; Flannery, John G; Corbo, Joseph C; Kefalov, Vladimir J

2015-02-01

Mutations in the cellular retinaldehyde-binding protein (CRALBP, encoded by RLBP1) can lead to severe cone photoreceptor-mediated vision loss in patients. It is not known how CRALBP supports cone function or how altered CRALBP leads to cone dysfunction. Here, we determined that deletion of Rlbp1 in mice impairs the retinal visual cycle. Mice lacking CRALBP exhibited M-opsin mislocalization, M-cone loss, and impaired cone-driven visual behavior and light responses. Additionally, M-cone dark adaptation was largely suppressed in CRALBP-deficient animals. While rearing CRALBP-deficient mice in the dark prevented the deterioration of cone function, it did not rescue cone dark adaptation. Adeno-associated virus-mediated restoration of CRALBP expression specifically in Müller cells, but not retinal pigment epithelial (RPE) cells, rescued the retinal visual cycle and M-cone sensitivity in knockout mice. Our results identify Müller cell CRALBP as a key component of the retinal visual cycle and demonstrate that this pathway is important for maintaining normal cone-driven vision and accelerating cone dark adaptation.

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.

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...

A Standalone Vision Impairments Simulator for Java Swing Applications

Science.gov (United States)

Oikonomou, Theofanis; Votis, Konstantinos; Korn, Peter; Tzovaras, Dimitrios; Likothanasis, Spriridon

A lot of work has been done lately in an attempt to assess accessibility. For the case of web rich-client applications several tools exist that simulate how a vision impaired or colour-blind person would perceive this content. In this work we propose a simulation tool for non-web JavaTM Swing applications. Developers and designers face a real challenge when creating software that has to cope with a lot of interaction situations, as well as specific directives for ensuring an accessible interaction. The proposed standalone tool will assist them to explore user-centered design and important accessibility issues for their JavaTM Swing implementations.

Colour chemistry

International Nuclear Information System (INIS)

Hong-Mo, C.

1978-10-01

Colour is now popularly believed to be the basis of strong interactions and as evidence for such a fundamental new degree of freedom one should expect an entirely new class of phenomena qualitatively different from those in a colourless world. One place to seek such manifestations is in spectroscopy, where a new degree of freedom should lead to a richer spectrum. this approach is here discussed with especial reference to the case of diquoniums. The very existence of M-diquoniums, whose spectrum has been calculated and is shown, would be a verification of colour. (U.K.)

The Categorisation of Non-Categorical Colours: A Novel Paradigm in Colour Perception

Science.gov (United States)

Cropper, Simon J.; Kvansakul, Jessica G. S.; Little, Daniel R.

2013-01-01

In this paper, we investigate a new paradigm for studying the development of the colour ‘signal’ by having observers discriminate and categorize the same set of controlled and calibrated cardinal coloured stimuli. Notably, in both tasks, each observer was free to decide whether two pairs of colors were the same or belonged to the same category. The use of the same stimulus set for both tasks provides, we argue, an incremental behavioural measure of colour processing from detection through discrimination to categorisation. The measured data spaces are different for the two tasks, and furthermore the categorisation data is unique to each observer. In addition, we develop a model which assumes that the principal difference between the tasks is the degree of similarity between the stimuli which has different constraints for the categorisation task compared to the discrimination task. This approach not only makes sense of the current (and associated) data but links the processes of discrimination and categorisation in a novel way and, by implication, expands upon the previous research linking categorisation to other tasks not limited to colour perception. PMID:23536899

Exposure of Polish children to Southampton food colours.

Science.gov (United States)

Gajda-Wyrębek, J; Kuźma, K; Świtka, A; Jarecka, J; Beresińska, M; Postupolski, J

2017-01-01

A study published in 2007 showed that the intake of six food colours (the so-called 'Southampton colours') may have an adverse effect on activity and attention in children. The present study set out to assess the exposure of Polish children (3 and 8-9 years old, n = 149) to six of the target colours. Two methods were used to evaluate colour consumption by children: scenario 1 using the maximum permitted levels (MPLs) and actual food consumption data; and scenario 2 using the actual levels in food and actual food consumption data. The data on the actual consumption of food containing the colours was collected using a 7-day questionnaire survey. The results of laboratory analysis of food consumed by children provided data on the actual levels of the colours in food. Consumption of the colours estimated by scenario 1 in any case did not exceed the acceptable daily intakes (ADIs) of the colours in both age groups of children. For more refined colour intake (scenario 2), isolated cases exceeding the ADI were recorded for four colours, but assuming that manufacturers comply with the current legislation on MPL of colours in food, the intake of the colours assessed in scenario 2 should not be a reason for exceeding of ADIs for the target food colours.

Exploring the benefit of synaesthetic colours: testing for "pop-out" in individuals with grapheme-colour synaesthesia.

Science.gov (United States)

Rich, Anina N; Karstoft, Karen-Inge

2013-01-01

In grapheme-colour synaesthesia, letters, numbers, and words elicit involuntary colour experiences. Recently, there has been much emphasis on individual differences and possible subcategories of synaesthetes with different underlying mechanisms. In particular, there are claims that for some, synaesthesia occurs prior to attention and awareness of the inducing stimulus. We first characterized our sample using two versions of the "Synaesthetic Congruency Task" to distinguish "projector" and "associator" synaesthetes who may differ in the extent to which their synaesthesia depends on attention and awareness. We then used a novel modification of the "Embedded Figures Task" that included a set-size manipulation to look for evidence of preattentive "pop-out" from synaesthetic colours, at both a group and an individual level. We replicate an advantage for synaesthetes over nonsynaesthetic controls on the Embedded Figures Task in accuracy, but find no support for pop-out of synaesthetic colours. We conclude that grapheme-colour synaesthetes are fundamentally similar in their visual processing to the general population, with the source of their unusual conscious colour experiences occurring late in the cognitive hierarchy.

Brown colour in natural diamond and interaction between the brown related and other colour-inducing defects

International Nuclear Information System (INIS)

Fisher, D; Sibley, S J; Kelly, C J

2009-01-01

Absorption spectroscopy results on a range of type II diamonds are presented which enable the electronic states associated with them to be mapped out. High pressure, high temperature treatment of brown type IIa diamonds has enabled an activation energy for the removal of the brown colour of 8.0 ± 0.3 eV to be determined and this is consistent with expectations associated with the currently accepted vacancy cluster model for the defect. Theoretical calculations suggest that this defect will generate partially filled gap states about 1 eV above the valence band. Data on the photochromic behaviour of bands producing pink colour and their relation to brown colour are presented; these suggest that the pink bands are produced from two independent transitions with ground states close to each other just below the middle of the band gap. Compensation of neutral boron by charge transfer from states associated with brown colour is demonstrated via the correlated increase in neutral boron and decrease in brown colour on high pressure, high temperature treatment to remove the defects causing the brown colour.

Colours as Non-Verbal Signs on Packages

OpenAIRE

Kauppinen, Hannele

2005-01-01

Colour is an essential aspect of our daily life, and still, it is a neglected issue within marketing research. The main reason for studying colours is to understand the impact of colours on consumer behaviour, and thus, colours should be studied when it comes to branding, advertising, packages, interiors, and the clothes of the employees, for example. This was an exploratory study about the impact of colours on packages. The focus was on low-involvement purchasing, where the consumer puts...

Laser-induced plasmonic colours on metals

Science.gov (United States)

Guay, Jean-Michel; Calà Lesina, Antonino; Côté, Guillaume; Charron, Martin; Poitras, Daniel; Ramunno, Lora; Berini, Pierre; Weck, Arnaud

2017-07-01

Plasmonic resonances in metallic nanoparticles have been used since antiquity to colour glasses. The use of metal nanostructures for surface colourization has attracted considerable interest following recent developments in plasmonics. However, current top-down colourization methods are not ideally suited to large-scale industrial applications. Here we use a bottom-up approach where picosecond laser pulses can produce a full palette of non-iridescent colours on silver, gold, copper and aluminium. We demonstrate the process on silver coins weighing up to 5 kg and bearing large topographic variations (~1.5 cm). We find that colours are related to a single parameter, the total accumulated fluence, making the process suitable for high-throughput industrial applications. Statistical image analyses of laser-irradiated surfaces reveal various nanoparticle size distributions. Large-scale finite-difference time-domain computations based on these nanoparticle distributions reproduce trends seen in reflectance measurements, and demonstrate the key role of plasmonic resonances in colour formation.

Colour change in a structural ornament is related to individual quality, parasites and mating patterns in the blue tit

Science.gov (United States)

Badás, E. P.; Martínez, J.; Rivero-de Aguilar, J.; Ponce, C.; Stevens, M.; Merino, S.

2018-02-01

Carry-over effects refer to processes that occur in one season and influence fitness in the following. In birds, two costly activities, namely reproduction and moult, are restricted to a small time window, and sometimes overlap. Thus, colour in newly moulted feathers is likely to be affected by the costs of reproduction. Using models of bird vision we investigated male colour change in a free-living population of blue tits ( Cyanistes caeruleus) in three sampling occasions: spring 1, winter and spring 2. We related crown, tail, breast and cheek feather colouration after the moult (winter) to the intensity of infections by blood parasites during reproduction (spring 1). In the following spring (spring 2), we explored mating patterns with respect to changes in feather colour (springs 1 vs. 2). Males that were less intensely infected by the malaria parasite Plasmodium while breeding showed purer white cheek feathers in winter, which may indicate higher feather quality. Increased brightness in the white cheek was associated with better body condition during reproduction. In the following season, males with brighter cheeks paired with females that had noticeably brighter cheek patches compared to the male's previous mate. These results suggest that the conditions experienced during reproduction are likely to affect moult and thus feather colouration, at least in the white patch. High quality individuals may allocate resources efficiently during reproduction increasing future reproductive success through variation in mating patterns. Carry-over effects from reproduction might extend not only to the non-breeding phase, but also to the following breeding season.

Coloured phase singularities

International Nuclear Information System (INIS)

Berry, M.V.

2002-01-01

For illumination with white light, the spectra near a typical isolated phase singularity (nodal point of the component wavelengths) can be described by a universal function of position, up to linear distortion and a weak dependence on the spectrum of the source. The appearance of the singularity when viewed by a human observer is predicted by transforming the spectrum to trichromatic variables and chromaticity coordinates, and then rendering the colours, scaled to constant luminosity, on a computer monitor. The pattern far from the singularity is a white that depends on the source temperature, and the centre of the pattern is flanked by intensely coloured 'eyes', one orange and one blue, separated by red, and one of the eyes is surrounded by a bright white circle. Only a small range of possible colours appears near the singularity; in particular, there is no green. (author)

Human colour in mate choice and competition.

Science.gov (United States)

Rowland, Hannah M; Burriss, Robert P

2017-07-05

The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

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.

An RGB Approach to Prismatic Colours

Science.gov (United States)

Theilmann, Florian; Grusche, Sascha

2013-01-01

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

Colour development in the apple orchard

NARCIS (Netherlands)

Tijskens, L.M.M.; Unuk, T.; Stanislav Tojnko, S.; Hribar, J.; Simcic, M.

2011-01-01

Colour is traditionally one of the important appearance features of all fruit for consumers in deciding to buy them. Colour is therefore important in the postharvest supply chain. But where does that colour of fruit come from? Clearly the period of growing and the circumstances during growth are

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.

New particles and breaking the colour symmetry

International Nuclear Information System (INIS)

Krolikowski, W.

1975-01-01

In the framework of one-gluon-exchange static forces mediated by a colour octet or nonet of vector gluons, we discuss quark binding in coloured-meson states and its connection with breaking the colour symmetry. A possible identification of psi (3.1), psi(3.7) and the broad bump at 4.1 GeV with some coloured bound states of quarks and antiquarks is pointed out. This identification implies the existence of a second bump in the region of 5 GeV. The general conclusion of the paper is that the colour interpretation of the new particles may be true only if the colour symmetry is badly broken (provided the considered forces are relevant). (author)

Culture of colour in the city

Directory of Open Access Journals (Sweden)

Vasiljević-Tomić Dragana

2009-01-01

Full Text Available The phenomenon of colour is examined through the evolution of colour and development of culture of colour, which significantly affects the colouristic priorities of people and the colour of the city itself. The terms functional colour and climate of colour are also considered, as some of the most important characteristics of architectural and urban design practice. The quality of the urban public space is directly predicated by cultural identity, and indirectly by appearance of polychromy in urban public space. The need to improve the quality of life in the city represents one of the key motives for operating in urban space, i.e. commencing the process of architectural and urban designing. Historical architectural policrhomy represents the basis for appearance of colour in public space. The complexity of colouristic attributes of the urban public space is conditioned by the basic characteristics: colouristic priorities, harmony of coloured spatial structures and materials in designing the polychrome ambient in the city. The factors that shape the colouristic ambient of the city are: characteristics of nature and climate, interrelations of colour and shape, as well as the experience of the form of the urban public space while preserving its identity. The acquired experiences point to the possibility of redefining the concepts of urban public space in planning and designing practice. The synthesized knowledge is sublimed through examination of the elasticity of its boundaries in accordance to the preservation of the identity of place and the future transformations of the city as well as of its users. The new principles are formed upon which the transformed model of the urban public space as a polychrome ambient is built.

A Bayesian Model of the Memory Colour Effect

OpenAIRE

Witzel, Christoph; Olkkonen, Maria; Gegenfurtner, Karl R.

2018-01-01

According to the memory colour effect, the colour of a colour-diagnostic object is not perceived independently of the object itself. Instead, it has been shown through an achromatic adjustment method that colour-diagnostic objects still appear slightly in their typical colour, even when they are colourimetrically grey. Bayesian models provide a promising approach to capture the effect of prior knowledge on colour perception and to link these effects to more general effects of cue integration....

A Bayesian model of the memory colour effect.

OpenAIRE

Witzel, Christoph; Olkkonen, Maria; Gegenfurtner, Karl R.

2018-01-01

According to the memory colour effect, the colour of a colour-diagnostic object is not perceived independently of the object itself. Instead, it has been shown through an achromatic adjustment method that colour-diagnostic objects still appear slightly in their typical colour, even when they are colourimetrically grey. Bayesian models provide a promising approach to capture the effect of prior knowledge on colour perception and to link these effects to more general effects of cue integration....

Colour reconstruction of underwater images

OpenAIRE

Hoth, Julian; Kowalczyk, Wojciech

2017-01-01

Objects look very different in the underwater environment compared to their appearance in sunlight. Images with correct colouring simplify the detection of underwater objects and may allow the use of visual SLAM algorithms developed for land-based robots underwater. Hence, image processing is required. Current algorithms focus on the colour reconstruction of scenery at diving depth where different colours can still be distinguished. At greater depth this is not the case. In this study it is i...

The Attentional Capture of Colour in Visual Interface Design

DEFF Research Database (Denmark)

Andersen, Emil; Maier, Anja

2017-01-01

The use of colour is an integral component in visual interface design for creating separation between objects and for conveying meaning. It has previously been established that colours can be separated in a hierarchy of primary colours and secondary colours, and that colours are consistently...... in a controlled environment, in which 11 participants scanned a 20 item display for a coloured target amongst coloured distractors. We found evidence to support that primary colours capture attention significantly more than secondary colours, and inconclusive evidence that colours convey their meaning...... at a sufficiently early level of processing to influence attention. We end by discussing implications of our results for design practice and research in psychology....

Colour constancy in natural images through colour naming and sensor sharpening

OpenAIRE

Vázquez Corral, Javier

2014-01-01

Advisors: Maria Vanrell, Graham Finlayson. Date and location of PhD thesis defense: 28 February 2011, Universitat Autònoma de Barcelona Colour is derived from three physical properties: incident light, object reflectance and sensor sensitivities. Incident light varies under natural conditions; hence, recovering scene illuminant is an important issue in computational colour. One way to deal with this problem under calibrated conditions is by following three steps, 1) building a narrow-band ...

Colour: code, mode, modality

DEFF Research Database (Denmark)

van Leeuwen, Theo

2014-01-01

This article uses a social semiotic approach to discuss the influence of film, video and digital technologies on the way colour is used in audiovisual media......This article uses a social semiotic approach to discuss the influence of film, video and digital technologies on the way colour is used in audiovisual media...

Colour discrimination and categorisation in Williams syndrome.

Science.gov (United States)

Farran, Emily K; Cranwell, Matthew B; Alvarez, James; Franklin, Anna

2013-10-01

Individuals with Williams syndrome (WS) present with impaired functioning of the dorsal visual stream relative to the ventral visual stream. As such, little attention has been given to ventral stream functions in WS. We investigated colour processing, a predominantly ventral stream function, for the first time in nineteen individuals with Williams syndrome. Colour discrimination was assessed using the Farnsworth-Munsell 100 hue test. Colour categorisation was assessed using a match-to-sample test and a colour naming task. A visual search task was also included as a measure of sensitivity to the size of perceptual colour difference. Results showed that individuals with WS have reduced colour discrimination relative to typically developing participants matched for chronological age; performance was commensurate with a typically developing group matched for non-verbal ability. In contrast, categorisation was typical in WS, although there was some evidence that sensitivity to the size of perceptual colour differences was reduced in this group. Copyright © 2013 Elsevier Ltd. All rights reserved.

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......-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...

Balancing selection maintains cryptic colour morphs.

Science.gov (United States)

Wellenreuther, Maren

2017-11-01

Animals display incredibly diverse colour patterns, a testament to evolution's endless innovation in shaping life. In many species, the interplay between males and females in the pursuit of mates has driven the evolution of a myriad of colour forms, from the flashy peacock tail feathers to the tiniest colour markings in damselflies. In others, colour provides crypsis by allowing to blend into the background and to escape the eyes of predators. While the obvious benefits of this dazzling diversity for reproduction and survival seem straightforward, its maintenance is not. Theory predicts that genetic drift and various forms of selection reduce variation over time, making the persistence of colour variants over generations a puzzle. In this issue of Molecular Ecology, Lindtke et al. () study the cryptic colour morphs of Timema cristinae walking sticks to shed light on the genetic architecture and mechanisms that allow colour polymorphism maintenance over long timescales. By combining genome-wide data with phenotyping information from natural populations, they were able to map the green and melanistic colour to one genomic region with highly reduced effective recombination rate between two main chromosomal variants, consistent with an inversion polymorphism. These two main chromosomal variants showed geographically widespread heterozygote excess, and genomic signatures consistent with long-term balancing selection. A younger chromosomal variant was detected for the third morph, the green-striped colour morphs, in the same genomic regions as the melanistic and the green-unstriped morphs. Together, these results suggest that the genetic architecture of cryptic T. cristinae morphs is caused by nonrecombining genomic blocks that have been maintained over extended time periods by balancing selection making this study one of the few available empirical examples documenting that balancing selection of various forms may play an important role in maintaining adaptive genetic

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.

Radiation-reversible material carriers of different colour

International Nuclear Information System (INIS)

Hofmann, G.

1976-01-01

A suggestion is made instead of using coloured material carriers - the cones and cylindrical tubes in spinning mills and weaving mills are given as example - to use such ones which change colour with irradiation and keep this colour until a new radiation impulse causes a new colour which differs well from the first one. (No data on material or type of radiation are given.) (UWI) [de

Colour-specific differences in attentional deployment for equiluminant pop-out colours: evidence from lateralised potentials.

Science.gov (United States)

Pomerleau, Vincent Jetté; Fortier-Gauthier, Ulysse; Corriveau, Isabelle; Dell'Acqua, Roberto; Jolicœur, Pierre

2014-03-01

We investigated how target colour affected behavioural and electrophysiological results in a visual search task. Perceptual and attentional mechanisms were tracked using the N2pc component of the event-related potential and other lateralised components. Four colours (red, green, blue, or yellow) were calibrated for each participant for luminance through heterochromatic flicker photometry and equated to the luminance of grey distracters. Each visual display contained 10 circles, 1 colored and 9 grey, each of which contained an oriented line segment. The task required deploying attention to the colored circle, which was either in the left or right visual hemifield. Three lateralised ERP components relative to the side of the lateral coloured circle were examined: a posterior contralateral positivity (Ppc) prior to N2pc, the N2pc, reflecting the deployment of visual spatial attention, and a temporal and contralateral positivity (Ptc) following N2pc. Red or blue stimuli, as compared to green or yellow, had an earlier N2pc. Both the Ppc and Ptc had higher amplitudes to red stimuli, suggesting particular selectivity for red. The results suggest that attention may be deployed to red and blue more quickly than to other colours and suggests special caution when designing ERP experiments involving stimuli in different colours, even when all colours are equiluminant. Copyright © 2013 Elsevier B.V. All rights reserved.

The theory and phenomenology of coloured quark models

CERN Document Server

Close, F E

1975-01-01

A general introduction to coloured quark models is given and their phenomenology is described with particular reference to the new particles. It is shown that there are essentially three types of colour models with colour excitation when the colour group is SU(3)- Han-Nambu, Greenberg and a model which has the same charges as that of Tati and which can be thought of as the Gell-Mann colour scheme with excitation of the colour degrees of freedom. Particular attention is paid to the four problems of colour models for psi phenomenology-the radiative decays, the G parity conservation, the lack of deep inelastic threshold phenomena and the apparent discovery of dileptons at SPEAR. (40 refs).

The theory and phenomenology of coloured quark models

International Nuclear Information System (INIS)

Close, F.E.

1975-01-01

A general introduction to coloured quark models is given and their phenomenology is described with particular reference to the new particles. It is shown that there are essentially three types of colour models with colour excitation when the colour group is SU(3) - Han-Nambu, Greenberg and a model which has the same charges as that of Tati and which can be thought of as the Gell-Mann colour scheme with excitation of the colour degrees of freedom. Particular attention is paid to the four problems of colour models for PSI phenomenology - the radiative decays, the G parity conservation, the lack of deep inelastic threshold phenomena and the apparent discovery of dileptons at SPEAR. (author)

Energy losses (gains) of massive coloured particles in stochastic colour medium

International Nuclear Information System (INIS)

Leonidov, A.; Rossijskaya Akademiya Nauk, Moscow

1995-01-01

The propagation of massive coloured particles in stochastic background chromoelectric field is studied using the semiclassical equations of motion. Depending on the nature of the stochastic background we obtain the formulae for the energy losses of heavy coloured projectile in nonperturbative hadronic medium and for the energy gains in the stochastic field present, e.g., in the turbulent plasma. The result appears to be significantly dependent on the form of the correlation function of stochastic external field. (orig.)

Comparison of radiation-induced colouration images, thermoluminescence, and after-glow colour images with aluminium impurity distribution in Japanese twin quartzes

International Nuclear Information System (INIS)

Hashimoto, Tetsuo; Ojima, Tetsu; Takahashi, Eishi; Konishi, Masayoshi; Kanemaki, Motoko.

1995-01-01

After-glow colour images (AGCI) and thermoluminescence (TL) from Japanese twin quartz slices have been successfully photographed by means of a commercially available negative colour film after the irradiation of X-rays. After-glow colour images (AGCI) offered very interesting distinction of colour images; the core part showed the colour changed from sky blue with zonal orange to blue with increasing absorbed doses, whereas the outer parts maintained orange AG colour giving clear boundary. On the other hand, the radiation-induced colour (blackish or brownish) center image (CCI) appeared at the core portion, while thermoluminescence colour images (TLCI) also consisted of two portions distinguishable into stripe and zonal bluish core and faint TL emission part in outer ones. These luminescence colour images, probably reflecting the formation mechanism of Japanese twin quartzes, are evidently correlated with the concentration patterns of aluminium impurity obtained by an EPMA (electron probe microanalyzer) method. From these radiation-induced images, it was assumed that the conditions of crystal formation should be greatly different between the core and the outer parts; the outer parts were secondarily started to grow from hydrothermal solution with higher Al-concentration after the initial formation of single core. (author)

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...

Whorfian effects on colour memory are not reliable.

Science.gov (United States)

Wright, Oliver; Davies, Ian R L; Franklin, Anna

2015-01-01

The Whorfian hypothesis suggests that differences between languages cause differences in cognitive processes. Support for this idea comes from studies that find that patterns of colour memory errors made by speakers of different languages align with differences in colour lexicons. The current study provides a large-scale investigation of the relationship between colour language and colour memory, adopting a cross-linguistic and developmental approach. Colour memory on a delayed matching-to-sample (XAB) task was investigated in 2 language groups with differing colour lexicons, for 3 developmental stages and 2 regions of colour space. Analyses used a Bayesian technique to provide simultaneous assessment of two competing hypotheses (H1-Whorfian effect present, H0-Whorfian effect absent). Results of the analyses consistently favoured H0. The findings suggest that Whorfian effects on colour memory are not reliable and that the importance of such effects should not be overestimated.

Dynamic simulation of color blindness for studying color vision requirements in practice

NARCIS (Netherlands)

Lucassen, M.P.; Alferdinck, J.W.A.M.

2006-01-01

We report on a dynamic simulation of defective color vision. Using an RGB video camera connected to a PC or laptop, the captured and displayed RGB colors are translated by our software into modified RGB values that simulate the color appearance of a person with a color deficiency. Usually, the

Scalable, full-colour and controllable chromotropic plasmonic printing

OpenAIRE

Xue, Jiancai; Zhou, Zhang-Kai; Wei, Zhiqiang; Su, Rongbin; Lai, Juan; Li, Juntao; Li, Chao; Zhang, Tengwei; Wang, Xue-Hua

2015-01-01

Plasmonic colour printing has drawn wide attention as a promising candidate for the next-generation colour-printing technology. However, an efficient approach to realize full colour and scalable fabrication is still lacking, which prevents plasmonic colour printing from practical applications. Here we present a scalable and full-colour plasmonic printing approach by combining conjugate twin-phase modulation with a plasmonic broadband absorber. More importantly, our approach also demonstrates ...

Field-portable pixel super-resolution colour microscope.

Directory of Open Access Journals (Sweden)

Alon Greenbaum

Full Text Available Based on partially-coherent digital in-line holography, we report a field-portable microscope that can render lensfree colour images over a wide field-of-view of e.g., >20 mm(2. This computational holographic microscope weighs less than 145 grams with dimensions smaller than 17×6×5 cm, making it especially suitable for field settings and point-of-care use. In this lensfree imaging design, we merged a colorization algorithm with a source shifting based multi-height pixel super-resolution technique to mitigate 'rainbow' like colour artefacts that are typical in holographic imaging. This image processing scheme is based on transforming the colour components of an RGB image into YUV colour space, which separates colour information from brightness component of an image. The resolution of our super-resolution colour microscope was characterized using a USAF test chart to confirm sub-micron spatial resolution, even for reconstructions that employ multi-height phase recovery to handle dense and connected objects. To further demonstrate the performance of this colour microscope Papanicolaou (Pap smears were also successfully imaged. This field-portable and wide-field computational colour microscope could be useful for tele-medicine applications in resource poor settings.

Recent developments in computer vision-based analytical chemistry: A tutorial review.

Science.gov (United States)

Capitán-Vallvey, Luis Fermín; López-Ruiz, Nuria; Martínez-Olmos, Antonio; Erenas, Miguel M; Palma, Alberto J

2015-10-29

Chemical analysis based on colour changes recorded with imaging devices is gaining increasing interest. This is due to its several significant advantages, such as simplicity of use, and the fact that it is easily combinable with portable and widely distributed imaging devices, resulting in friendly analytical procedures in many areas that demand out-of-lab applications for in situ and real-time monitoring. This tutorial review covers computer vision-based analytical (CVAC) procedures and systems from 2005 to 2015, a period of time when 87.5% of the papers on this topic were published. The background regarding colour spaces and recent analytical system architectures of interest in analytical chemistry is presented in the form of a tutorial. Moreover, issues regarding images, such as the influence of illuminants, and the most relevant techniques for processing and analysing digital images are addressed. Some of the most relevant applications are then detailed, highlighting their main characteristics. Finally, our opinion about future perspectives is discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

IRIS COLOUR CLASSIFICATION SCALES – THEN AND NOW

Science.gov (United States)

Grigore, Mariana; Avram, Alina

2015-01-01

Eye colour is one of the most obvious phenotypic traits of an individual. Since the first documented classification scale developed in 1843, there have been numerous attempts to classify the iris colour. In the past centuries, iris colour classification scales has had various colour categories and mostly relied on comparison of an individual’s eye with painted glass eyes. Once photography techniques were refined, standard iris photographs replaced painted eyes, but this did not solve the problem of painted/ printed colour variability in time. Early clinical scales were easy to use, but lacked objectivity and were not standardised or statistically tested for reproducibility. The era of automated iris colour classification systems came with the technological development. Spectrophotometry, digital analysis of high-resolution iris images, hyper spectral analysis of the human real iris and the dedicated iris colour analysis software, all accomplished an objective, accurate iris colour classification, but are quite expensive and limited in use to research environment. Iris colour classification systems evolved continuously due to their use in a wide range of studies, especially in the fields of anthropology, epidemiology and genetics. Despite the wide range of the existing scales, up until present there has been no generally accepted iris colour classification scale. PMID:27373112

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).

The role of colour in implicit and explicit memory performance.

Science.gov (United States)

Vernon, David; Lloyd-Jones, Toby J

2003-07-01

We present two experiments that examine the effects of colour transformation between study and test (from black and white to colour and vice versa, of from incorrectly coloured to correctly coloured and vice versa) on implicit and explicit measures of memory for diagnostically coloured natural objects (e.g., yellow banana). For naming and coloured-object decision (i.e., deciding whether an object is correctly coloured), there were shorter response times to correctly coloured-objects than to black-and-white and incorrectly coloured-objects. Repetition priming was equivalent for the different stimulus types. Colour transformation did not influence priming of picture naming, but for coloured-object decision priming was evident only for objects remaining the same from study to test. This was the case for both naming and coloured-object decision as study tasks. When participants were asked to consciously recognize objects that they had named or made coloured-object decisions to previously, whilst ignoring their colour, colour transformation reduced recognition efficiency. We discuss these results in terms of the flexibility of object representations that mediate priming and recognition.

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…

Causes of vision impairment and assessment of need for low vision services for students of blind schools in Nepal.

Science.gov (United States)

Kansakar, I; Thapa, H B; Salma, K C; Ganguly, S; Kandel, R P; Rajasekaran, S

The present study is first of its kind to evaluate causes of visual impairment of blind students in Nepal and assess their need for low vision rehabilitation services. To evaluate causes of vision impairment of students enrolled in blind schools in Nepal and assess the need for low vision rehabilitation services in these students. A survey was conducted in 12 blind schools in Nepal, which were registered with Nepal Association for Welfare of Blindness (NAWB).It was conducted by a team of an ophthalmologist and an optometrist, by using standard eye examination protocols of the World Health Organization Prevention of Blindness Program (WHO/PBL). Of the 345 students enrolled in 12 schools, 285 students were examined (response rate of 82.61%). The students were in the 5 - 29 years age group. Nearly three-fourth of the children had become blind within one year of age and 52.3% visually impaired at birth and 20.7% developed vision impairment within one year of age. After refraction, 26 students (9.12%) had mild visual impairment, 21 students (7.37%) had severe visual impairment and 238 students (83.51%) were blind. The main cause of vision impairment was found to be corneal 35.79% and retina diseases, mainly dystrophy, 20.35% followed by problems with the whole globe, lens and optic nerve, accounting for 13.33%, 12.63% and 12.98% respectively. The major etiological factors were those of childhood such as Vitamin A deficiency, measles and similar causes (42.11%) followed by hereditary causes (25.26%). Of the total students examined, 48.07% were visually impaired due to preventable causes and 16.14% treatable aggregating to 64.21% of avoidable blindness. Fifty seven (28.22%) students could read smaller than 2 M print size after low vision assessment for near and 33(15.78%) students benefited with telescopic trial for distance low vision. In Nepal, renewed focus on providing best possible quality of life for visually impaired children by proper low vision assessment and eye

Relationship between natural tooth shade and skin colour.

Science.gov (United States)

Nourbakhsh, M; Mousavinejad, N; Adli, A R; Harati, M

2013-06-01

The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group.

Looking at anything that is green when hearing "frog": how object surface colour and stored object colour knowledge influence language-mediated overt attention.

Science.gov (United States)

Huettig, Falk; Altmann, Gerry T M

2011-01-01

Three eye-tracking experiments investigated the influence of stored colour knowledge, perceived surface colour, and conceptual category of visual objects on language-mediated overt attention. Participants heard spoken target words whose concepts are associated with a diagnostic colour (e.g., "spinach"; spinach is typically green) while their eye movements were monitored to (a) objects associated with a diagnostic colour but presented in black and white (e.g., a black-and-white line drawing of a frog), (b) objects associated with a diagnostic colour but presented in an appropriate but atypical colour (e.g., a colour photograph of a yellow frog), and (c) objects not associated with a diagnostic colour but presented in the diagnostic colour of the target concept (e.g., a green blouse; blouses are not typically green). We observed that colour-mediated shifts in overt attention are primarily due to the perceived surface attributes of the visual objects rather than stored knowledge about the typical colour of the object. In addition our data reveal that conceptual category information is the primary determinant of overt attention if both conceptual category and surface colour competitors are copresent in the visual environment.

[Retinitis pigmentosa and color vision deficiency in Kamigoto island, Nagasaki Prefecture].

Science.gov (United States)

Toda, S

1997-08-01

I studied two genetic diseases, retinitis pigmentosa (RP) and color vision anomaly, in Kamigoto, one of the off-shore islands in Nagasaki Prefecture. The Prevalance of RP patients in this island was estimated to be one in 473 persons. Among the RP patients observed, familial cases whose disorders are transmitted through successive generations comprised 25.7%. Although it seems that the inheritance mode of RP in these familial cases is autosomal dominant, an autosomal recessive fashion showing quasi-dominance cannot be ruled out, because inbreeding frequently occurs on this island. There were at least two types of RP, one with late onset (40 years of age or later) and the other with early onset, and patients with the latter RP tended to have a poor prognosis. Only a few RP patients had posterior subcapsular cataract, and none had pseudexfoliation in spite of advanced age. Color vision anomalies were found in 3.86% of high-school boys and in 0.41% of girls in this island, and they included protanopia (4.2%), protanomaly (10.4%), deuteranopia (37.5%), and deuteranomaly (47.9%). The prevalence in boys was comparable to that in the general Japanese population, but the prevalence in girls was higher in Kamigoto than in other districts. It is most likely that the unique findings regarding the two disorders reflect geographical and/or social features in Kamigoto island.

Several ways of breaking the colour symmetry

International Nuclear Information System (INIS)

Krolikowski, W.

1975-01-01

We discuss some cases of colour-symmetry breaking and its implications for quark binding by one-gluon-exchange forces. We pay special attention to the case, where colour-isospin and colour-hypercharge subsymmetries are preserved. Then, the ω-PHI-like mixing of colour-nonet components 0 and 8 leads to a Zweig-type approximate selection rule for decays of PHI-like meson = antiqsub(B)qsub(B)(qsub(B) is the '' blue'' quark) into ordinary mesons (and photons). (author)

Dimensionality of the Consumer Perceived Value of Product Colour

OpenAIRE

Kiehelä, Hanna

2014-01-01

Consumers’ product assessments are largely based on colour, and a product’s colour can increase consumer satisfaction, awareness and loyalty. However, existing colour research is fragmented and calls for theoretically-enhanced understandings of the role of colour in consumer product perception. The existing colour research mainly focuses on consumers’ immediate reactions when exposed to colours although studies show that consumers evaluate products differently in purchase and in use. There...

Colour Consideration for Waiting areas in hospitals

Science.gov (United States)

Zraati, Parisa

2012-08-01

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

Reduced Discrimination in the Tritanopic Confusion Line for Congenital Color Deficiency Adults.

Science.gov (United States)

Costa, Marcelo F; Goulart, Paulo R K; Barboni, Mirella T S; Ventura, Dora F

2016-01-01

In congenital color blindness the red-green discrimination is impaired resulting in an increased confusion between those colors with yellow. Our post-receptoral physiological mechanisms are organized in two pathways for color perception, a red-green (protanopic and deuteranopic) and a blue-yellow (tritanopic). We argue that the discrimination losses in the yellow area in congenital color vision deficiency subjects could generate a subtle loss of discriminability in the tritanopic channel considering discrepancies with yellow perception. We measured color discrimination thresholds for blue and yellow of tritanopic channel in congenital color deficiency subjects. Chromaticity thresholds were measured around a white background (0.1977 u', 0.4689 v' in the CIE 1976) consisting of a blue-white and white-yellow thresholds in a tritanopic color confusion line of 21 congenital colorblindness subjects (mean age = 27.7; SD = 5.6 years; 14 deuteranomalous and 7 protanomalous) and of 82 (mean age = 25.1; SD = 3.7 years) normal color vision subjects. Significant increase in the whole tritanopic axis was found for both deuteranomalous and protanomalous subjects compared to controls for the blue-white (F 2,100 = 18.80; p color confusion axis is significantly reduced in congenital color vision deficiency compared to normal subjects. Since yellow discrimination was impaired the balance of the blue-yellow channels is impaired justifying the increased thresholds found for blue-white discrimination. The weighting toward the yellow region of the color space with the deuteranomalous contributing to that perceptual distortion is discussed in terms of physiological mechanisms.

Exploring the benefit of synaesthetic colours: Testing for “pop-out” in individuals with grapheme–colour synaesthesia

Science.gov (United States)

Rich, Anina N.; Karstoft, Karen-Inge

2013-01-01

In grapheme–colour synaesthesia, letters, numbers, and words elicit involuntary colour experiences. Recently, there has been much emphasis on individual differences and possible subcategories of synaesthetes with different underlying mechanisms. In particular, there are claims that for some, synaesthesia occurs prior to attention and awareness of the inducing stimulus. We first characterized our sample using two versions of the “Synaesthetic Congruency Task” to distinguish “projector” and “associator” synaesthetes who may differ in the extent to which their synaesthesia depends on attention and awareness. We then used a novel modification of the “Embedded Figures Task” that included a set-size manipulation to look for evidence of preattentive “pop-out” from synaesthetic colours, at both a group and an individual level. We replicate an advantage for synaesthetes over nonsynaesthetic controls on the Embedded Figures Task in accuracy, but find no support for pop-out of synaesthetic colours. We conclude that grapheme–colour synaesthetes are fundamentally similar in their visual processing to the general population, with the source of their unusual conscious colour experiences occurring late in the cognitive hierarchy. PMID:23768150

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'.

ANALYSES OF ROCK SURFACE COLOUR CHANGES DUE TO WEATHERING

OpenAIRE

GOKAY, Mehmet Kemal

2018-01-01

Description parameters of rock masses and minerals include their colours as well. Colours appear in daylight for surfaced rock masses are changing slightly due to weathering layers which have been covering its surface gradually. Healthy human eyes can manage to differentiate visible light spectrum to identify colours of substances including rock masses. Then visible blackish colours of magnetite minerals, reddish colours of Terra- Rosa soils, greenish colours of weathered copper ore, pure whi...

ANALYSES OF ROCK SURFACE COLOUR CHANGES DUE TO WEATHERING

OpenAIRE

GÖKAY, Mehmet Kemal

2018-01-01

Description parameters of rock masses and minerals include their colours as well. Colours appear in daylight for surfaced rock masses are changing slightly due to weathering layers which have been covering its surface gradually. Healthy human eyes can manage to differentiate visible spectrum to identify the colours of substance including rock masses. Then visible blackish colours of magnetite minerals, reddish colours of Terra- Rosa soils, greenish colours of weathered copper ore, pure white ...

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.

Folic acid deficiency optic neuropathy: A case report

Directory of Open Access Journals (Sweden)

de Silva Punyanganie

2008-09-01

Full Text Available Abstract Introduction Nutritional optic neuropathies are uncommon and can be associated with gradual visual loss and optic atrophy or sudden vision loss and optic disc swelling. Case presentation A 44-year-old woman presented with a 4-week history of progressive visual loss and was noted to have bilateral retrobulbar optic neuropathy. No other clinical abnormality was noted. Investigations revealed severe folate deficiency with normal vitamin B12 levels. Her alcohol and tobacco consumption was moderate and subsequent correction of folate levels with oral supplementation has led to improvement in her visual acuity. Conclusion This case highlights an unusual presentation of folic acid deficiency that may present to the general physician.

Producing colour pictures from SCAN

International Nuclear Information System (INIS)

Robichaud, K.

1982-01-01

The computer code SCAN.TSK has been written for use on the Interdata 7/32 minicomputer which will convert the pictures produced by the SCAN program into colour pictures on a colour graphics VDU. These colour pictures are a more powerful aid to detecting errors in the MONK input data than the normal lineprinter pictures. This report is intended as a user manual for using the program on the Interdata 7/32, and describes the method used to produce the pictures and gives examples of JCL, input data and of the pictures that can be produced. (U.K.)

Synchronization analysis of coloured delayed networks under ...

Indian Academy of Sciences (India)

This paper investigates synchronization of coloured delayed networks under decentralized pinning intermittent control. To begin with, the time delays are taken into account in the coloured networks. In addition, we propose a decentralized pinning intermittent control for coloured delayed networks, which is different from that ...

Flare colours and luminosities

International Nuclear Information System (INIS)

Cristaldi, S.; Rodono, M.

1975-01-01

Flare colours determined from simultaneous UBV observations made at Catania Observatory and from sequential UBV observations made at McDonald Observatory are presented. They fit fairly well with the theoretical colours computed according to the Gurzadian's (1970) non-thermal model. Only part of the observed flare colours are consistent with the solar type models by Gershberg (1967) and Kunkel (1970). From a B-band patrol of UV Cet-type stars carried out from 1967 to 1972, some quantitative estimates of flare frequencies and luminosities and their average contributions to the stellar radiation are given. The corresponding parameters for the Sun, which were estimated from 'white light' flare activity, are also given for comparison. The Sun and V 1216 Sgr can be regarded as low-activity flare stars of the type found by Kunkel (1973). (Auth.)

ON f-EDGE COVER-COLOURING OF SIMPLE GRAPHS

Institute of Scientific and Technical Information of China (English)

Song Huimin; Liu Guizhen

2005-01-01

An f-edge cover-colouring of a graph G = (V, E) is an assignment of colours to the edges of G such that every colour appears at each vertex υ∈ V at least f(υ) times.The maximum number of colours needed to f-edge cover colour G is called the f-edge cover chromatic index of G, denoted by χfc(G). This paper gives that min[d(ν)-1/f(ν)] ≤χfc(G) ≤min[d(υ)/f(υ)].

Long-range correlations from colour confinement

International Nuclear Information System (INIS)

Jurkiewicz, J.; Zenczykowski, P.

1979-01-01

A class of independent parton emission models is generalized by the introduction of the colour degrees of freedom. In the proposed models colour confinement extorts strong long-range forward-backward correlations, the rise of one-particle inclusive distribution and the KNO scaling. It leads to the analytically calculable definite asymptotic predictions for the D/ ratio which depends only on the choice of the colour group. Multiplicity distribution develops a remarkably long tail. (author)

String Formation Beyond Leading Colour

CERN Document Server

Christiansen, Jesper R.

2015-08-03

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

Counting with Colours? Effect of Colours on the Numerical Abilities of House Crows (Corvus splendens) and Common Myna (Acridotheres tristis)

OpenAIRE

Rahman, Nor Amira Abdul; Ali, Zalila; Zuharah, Wan Fatma; Fadzly, Nik

2016-01-01

We conducted several aviary experiments to investigate the influence of colours in quantity judgments of two species of birds; house crow (Corvus splendens) and common myna (Acridotheres tristis). Different quantity (in seven different food proportions) of mealworms were presented nonsequentially to all birds using artificially coloured red mealworms, for experiment 1, and using artificially coloured green mealworms, for experiment 2. Both red and green coloured mealworms have no significant ...

Application of Modern Colour Measurement Dervices in Coloration Industries

Institute of Scientific and Technical Information of China (English)

CHUNG Y.S.; XIN John H.; SIN K.M.

2002-01-01

In colour measurement ralated industry, reflectance spectrophotometer is the one of the popular measuring machine for measutring colour and quality control. Colour communications is frequently confusing. This is because the colour appearance is subject to the influence of at least three different phenomena: the light source, the object and the visual system. The variation in either the radiant quantity or the spectral distribution of the source can alter the observed colour. Because of this reason,the objective quantitative tool, colour measurement equipment and communication method; become more important in evaluating of the colour. In fact, based on the advanced in computer system and electronic device,the colour measurement becomes more and more accuracy, especiany in spectrophotometer measurement.In this paper, we will focus on the review of modern spectrophotometers in coloration industries.

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…

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

Influence of drug colour on perceived drug effects and efficacy.

Science.gov (United States)

Tao, Da; Wang, Tieyan; Wang, Tieshan; Qu, Xingda

2018-02-01

A drug's physical characteristics, such as colour, could be factors influencing its therapeutic effects. It is not well understood whether people's expectations on drug effects and efficacy are affected by colour, especially among Chinese population. This study was conducted to examine people's expectations on drug effects and efficacy on the basis of drug colour, and to reveal possible gender differences in colour-related drug expectations. Participants (n = 224) were asked to classify seven single-coloured and six two-coloured capsules into one of four categories of drug effects, and to indicate the strength of drug efficacy. It is found that all the coloured capsules yielded non-chance distributions in classifications of drug effects, with six single-coloured and four two-coloured capsules associated with specific drug effects. Colour also conveyed differential strengths of drug efficacy in general and in relation to specific drug effects. There were gender differences in drug expectations for some colours and colour combinations. Practitioner Summary: Drug colour was found to have impacts on perceived drug effects and efficacy. The findings from the present study can be used by ergonomics practitioners to design appropriate drug colours in support of drug differentiation, therapeutic effects and medication adherence.

Vision Assessment and Prescription of Low Vision Devices

OpenAIRE

Keeffe, Jill

2004-01-01

Assessment of vision and prescription of low vision devices are part of a comprehensive low vision service. Other components of the service include training the person affected by low vision in use of vision and other senses, mobility, activities of daily living, and support for education, employment or leisure activities. Specialist vision rehabilitation agencies have services to provide access to information (libraries) and activity centres for groups of people with impaired vision.

Kac's ring: The case of four colours

Indian Academy of Sciences (India)

2017-03-15

Mar 15, 2017 ... generalize the discussion to more than two colours. Although the generalization seems nearly trivial, it will be shown that there appear interesting, unanticipated technical difficulties or surprises when we consider four colours. In this work, we consider the Kac's ring with balls of four colours, calling them red ...

Red-Green Color Vision Impairment in Duchenne Muscular Dystrophy

Science.gov (United States)

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

2007-01-01

The present study evaluated the color vision of 44 patients with Duchenne muscular dystrophy (DMD) (mean age 14.8 years; SD 4.9) who were submitted to a battery of four different color tests: Cambridge Colour Test (CCT), Neitz Anomaloscope, Ishihara, and American Optical Hardy-Rand-Rittler (AO H-R-R). Patients were divided into two groups according to the region of deletion in the dystrophin gene: upstream of exon 30 (n=12) and downstream of exon 30 (n=32). The control group was composed of 70 age-matched healthy male subjects with no ophthalmological complaints. Of the patients with DMD, 47% (21/44) had a red-green color vision defect in the CCT, confirmed by the Neitz Anomaloscope with statistical agreement (P.05). Of the patients with deletion downstream of exon 30, 66% had a red-green color defect. No color defect was found in the patients with deletion upstream of exon 30. A negative correlation between the color thresholds and age was found for the controls and patients with DMD, suggesting a nonprogressive color defect. The percentage (66%) of patients with a red-green defect was significantly higher than the expected <10% for the normal male population (P<.001). In contrast, patients with DMD with deletion upstream of exon 30 had normal color vision. This color defect might be partially explained by a retina impairment related to dystrophin isoform Dp260. PMID:17503325

The evolutionary history of colour polymorphism in Ischnura damselflies.

Science.gov (United States)

Sánchez-Guillén, Rosa A; Cordero-Rivera, Adolfo; Rivas-Torres, Anais; Wellenreuther, Maren; Bybee, Seth; Hansson, Bengt; Velasquez-Vélez, María I; Realpe, Emilio; Chávez-Ríos, Jesús R; Villalobos, Fabricio; Dumont, Henri

2018-05-10

A major challenge in evolutionary biology consists of understanding how genetic and phenotypic variation is created and maintained. In the present study, we investigated the origin(s) and evolutionary patterns of the female-limited colour polymorphism in ischnuran damselflies. These consist of the presence of one to three colour morphs: one androchrome morph with a colouration that is similar to the male, and two gynochrome morphs (infuscans and aurantiaca) with female-specific colouration. We (i) documented the colour and mating system of 44 of the 75 taxa within the genus Ischnura, (ii) reconstructed the evolutionary history of colour and mating system to identify the ancestral state, (iii) evaluated the stability of the colour morph status over time, and (iv) tested for a correlation between colour and mating system. We found that the ances tral female colour of Ischnura was monomorphic and aurantiaca and that colour morph status changed over time; characterised by many gains and losses across the species tree. Our results further showed that colour polymorphism is significantly more frequent among polyandric species, whereas monandric species tend to be monomorphic. Research on some Ischnura species has shown that colour morphs have evolved to reduce male mating harassment, and our finding that the same phenotypic morphs have evolved multiple times (convergent evolution) suggests that several species in this genus might be experiencing similar selective pressures. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

A five-colour colour-coded mapping method for DCE-MRI analysis of head and neck tumours

International Nuclear Information System (INIS)

Yuan, J.; Chow, S.K.K.; Yeung, D.K.W.; King, A.D.

2012-01-01

Aim: To devise a method to convert the time–intensity curves (TICs) of head and neck dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data into a pixel-by-pixel colour-coded map for identifying normal tissues and tumours. Materials and methods: Twenty-three patients with head and neck squamous cell carcinoma (HNSCC) underwent DCE-MRI. TIC patterns of primary tumours, metastatic nodes, and normal tissues were assessed and a program was devised to convert the patterns into a classified colour-coded map. The enhancement patterns of tumours and normal tissue structures were evaluated and categorized into nine grades (0–8) based on the predominance of coloured pixels on maps. Results: Five identified TIC patterns were converted into a colour-coded map consisting of red (maximum enhancement), brown (continuous slow rise-up), yellow (rapid wash-in and wash-out), green (rapid wash-in and plateau), and blue (rapid wash-in and rise-up). The colour-coded map distinguished all 21 primary tumours and 15 metastatic nodes from normal structures. Primary tumours and metastatic nodes were colour coded as predominantly yellow (grades 1–2) in 17/21 and 6/15, green (grades 3–5) in 3/21 and 5/15, and blue (grades 6–7) in 1/21 and 4/15, respectively. Vessels were coded red in 46/46 (grade 0) and muscles were coded brown in 23/23 (grade 8). Salivary glands, thyroid glands, and palatine tonsils were coded into predominantly yellow (grade 1) in 46/46 and 10/10 and 18/22, respectively. Conclusion: DCE-MRI derived five-colour-coded mapping provides an objective easy-to-interpret method to assess the dynamic enhancement pattern of head and neck cancers.

Phenomenology of colour exotic fermions

International Nuclear Information System (INIS)

Luest, D.

1986-01-01

The authors discuss the phenomenological consequences of a dynamical scenario according to which the electroweak symmetry breaking and generation of fermion masses is due to fermions that transform under high colour representations. Particular emphasis is given to the predictions for rare processes and to the spectrum of high colour boundstates. (Auth.)

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 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 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.

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....

The role of vision processing in prosthetic vision.

Science.gov (United States)

Barnes, Nick; He, Xuming; McCarthy, Chris; Horne, Lachlan; Kim, Junae; Scott, Adele; Lieby, Paulette

2012-01-01

Prosthetic vision provides vision which is reduced in resolution and dynamic range compared to normal human vision. This comes about both due to residual damage to the visual system from the condition that caused vision loss, and due to limitations of current technology. However, even with limitations, prosthetic vision may still be able to support functional performance which is sufficient for tasks which are key to restoring independent living and quality of life. Here vision processing can play a key role, ensuring that information which is critical to the performance of key tasks is available within the capability of the available prosthetic vision. In this paper, we frame vision processing for prosthetic vision, highlight some key areas which present problems in terms of quality of life, and present examples where vision processing can help achieve better outcomes.

Genetics and evolution of colour patterns in reptiles.

Science.gov (United States)

Olsson, Mats; Stuart-Fox, Devi; Ballen, Cissy

2013-01-01

The study of coloration in the polyphyletic reptilians has flourished in the last two decades, in particular with respect to the underlying genetics of colour traits, the function of colours in social interactions, and ongoing selection on these traits in the wild. The taxonomic bias, however, is profound: at this level of resolution almost all available information is for diurnal lizards. Therefore, we focus on case studies, for which there are as complete causal sequences of colour evolution as possible, from phenotypic expression of variation in colour, to ongoing selection in the wild. For work prior to 1992 and for a broader coverage of reptilian coloration we refer the readers to Cooper and Greenburg's (Biology of the Reptilia, 1992) review. There are seven major conclusions we would like to emphasise: (a) visual systems in diurnal lizards are broadly conserved but among the wider range of reptiles in general, there is functionally important variation in the number and type of photoreceptors, spectral tuning of photopigments and optical properties of the eye; (b) coloration in reptiles is a function of complex interactions between structural and pigmentary components, with implications for both proximate control and condition dependence of colour expression; (c) studies of colour-variable species have enabled estimates of heritability of colour and colour patterns, which often show a simple Mendelian pattern of inheritance; (d) colour-polymorphic lizard species sometimes, but not always, show striking differences in genetically encoded reproductive tactics and provide useful models for studying the evolution and maintenance of polymorphism; (e) both male and female colours are sometimes, but not always, a significant component of socio-sexual signalling, often based on multiple traits; (f) evidence for effects of hormones and condition on colour expression, and trade-offs with immunocompetence and parasite load, is variable; (g) lizards show fading of colours

Complementary Colours for a Physicist

Science.gov (United States)

Babic, Vitomir; Cepic, Mojca

2009-01-01

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

Improper colouring of (random) unit disk graphs

NARCIS (Netherlands)

Kang, R.J.; Müller, T.; Sereni, J.S.

2008-01-01

For any graph G, the k-improper chromatic number ¿k(G) is the smallest number of colours used in a colouring of G such that each colour class induces a subgraph of maximum degree k. We investigate ¿k for unit disk graphs and random unit disk graphs to generalise results of McDiarmid and Reed

Mixed colour states in QCD confining vacuum

OpenAIRE

Buividovich, P. V.; Kuvshinov, V. I.

2005-01-01

We show that confinement of spinless heavy quarks in fundamental representation of $SU(N_{c})$ gauge group can be treated as decoherence of pure colour state into a white mixture of states. Decoherence rate is found to be proportional to the tension of QCD string and the distance between colour charges. The purity of colour states is calculated.

Geographical variation in colour of female threespine stickleback (Gasterosteus aculeatus).

Science.gov (United States)

French, Connor M; Ingram, Travis; Bolnick, Daniel I

2018-01-01

The ecological multifunctionality of colour often results in multiple selective pressures operating on a single trait. Most research on colour evolution focuses on males because they are the most conspicuous sex in most species. This bias can limit inferences about the ecological drivers of colour evolution. For example, little is known about population divergence in colour of female threespine stickleback ( Gasterosteus aculeatus ), which is among the most intensively-studied model vertebrates in evolution, ecology, and behaviour. In contrast, the evolution and ecology of colour in male stickleback has received considerable attention. One aspect of female colouration that is lacking previous research is non-ornamental body colour. Non-ornamental colour can play defensive and social roles, and indicate other aspects of female stickleback ecology. To remedy this knowledge gap, we measured the colour and brightness of one dorsal and one ventral lateral area on female stickleback from nine lake populations on Vancouver Island. We found that lake populations varied in overall colour brightness and dorso-ventral contrast. In addition, we found that female brightness increased with lake size, indicating potential ecological drivers of these colour differences. Our results demonstrate that there is substantial scope for future research on female colour diversification, which has been overlooked because past researchers focused on dramatic male nuptial colours.

Assimilation of ocean colour to improve the simulation and understanding of the North West European shelf-sea ecosystem

Science.gov (United States)

Ciavatta, Stefano; Brewin, Robert; Skakala, Jozef; Sursham, David; Ford, David

2017-04-01

Shelf-seas and coastal zones provide essential goods and services to humankind, such as fisheries, aquaculture, tourism and climate regulation. The understanding and management of these regions can be enhanced by merging ocean-colour observations and marine ecosystem simulations through data assimilation, which provides (sub)optimal estimates of key biogeochemical variables. Here we present a range of applications of ocean-colour data assimilation in the North West European shelf-sea. A reanalysis application illustrates that assimilation of error-characterized chlorophyll concentrations could provide a map of the shelf sea vulnerability to oxygen deficiency, as well as estimates of the shelf sea uptake of atmospheric carbon dioxide (CO2) in the last decade. The interannual variability of CO2 uptake and its uncertainty were related significantly to interannual fluctuations of the simulated primary production. However, the reanalysis also indicates that assimilation of total chlorophyll did not improve significantly the simulation of some other variables, e.g. nutrients. We show that the assimilation of alternative products derived from ocean colour (i.e. spectral diffuse attenuation coefficient and phytoplankton size classes) can overcome this limitation. In fact, these products can constrain a larger number of model variables, which define either the underwater light field or the structure of the lower trophic levels. Therefore, the assimilation of such ocean-colour products into marine ecosystem models is an advantageous novel approach to improve the understanding and simulation of shelf-sea environments.

Colour print workflow and methods for multilayering of colour and decorative inks using UV inkjet for fine art printing

Science.gov (United States)

Parraman, Carinna

2012-01-01

In order to increase density of colour and improve ink coverage when printing onto a range of non standard substrates, this paper will present research into multi-layering of colour and the appearance of colour at 'n' levels of ink coverage. Returning to our original investigation of artist's requirements when making inkjet prints, these observations are based on empirical approaches that address the need to present physical data that is more useful and meaningful to the designer. The study has used multi-pass printed colour charts to measure colour and to provide users with an understanding at a soft-preview level to demonstrate the appearance of printed colour on different substrates. Test results relating to the appearance of print on different surfaces, and a series of case studies will be presented using recent research into the capabilities of UV printing technology, which has widened the opportunities for the designer to print onto non-standard materials. It will also present a study into layering of greys and gloss in order to improve the appearance of printed images onto metal.

Marius Tscherning (1854-1939): his life and work in optical physiology

DEFF Research Database (Denmark)

Norn, Mogens; Jensen, O.A.

2004-01-01

Ophthalmology, Marius Tscherning, accommodation, colour vision, dark vision, entopic phenomena, medical history, ophthalmophacometer, optic physiology, photometric glasses, spectacle lenses......Ophthalmology, Marius Tscherning, accommodation, colour vision, dark vision, entopic phenomena, medical history, ophthalmophacometer, optic physiology, photometric glasses, spectacle lenses...

Music-colour synaesthesia: Concept, context and qualia.

Science.gov (United States)

Curwen, Caroline

2018-05-01

This review provides a commentary on coloured-hearing arising on hearing music: music-colour synaesthesia. Although traditionally explained by the hyperconnectivity theory (Ramachandran & Hubbard, 2001a) and the disinhibited feedback theory (Grossenbacher & Lovelace, 2001) as a purely perceptual phenomenon, the review of eight coloured-hearing neuroimaging studies shows that it may not be assumed that these explanations are directly translatable to music-colour synaesthesia. The concept of 'ideaesthesia' (Nikolić, 2009) and the role of conceptual and semantic inducers challenge the likelihood of a single mechanism underlying the cause of synaesthesia and argue for a move away from a purely sensory to sensory explanation. Finally, music-colour synaesthesia forms a challenge for established philosophical theories and the position of synaesthesia is considered within the larger context of musical qualia. Copyright © 2018 Elsevier Inc. All rights reserved.

Please pass me the skin coloured crayon!

DEFF Research Database (Denmark)

Zimmermann, Martina; Levisen, Carsten; Beck, Thorhalla Gudmundsdottir

2015-01-01

worldviews and idealised cognitive models embedded in skin-based colour concepts in contemporary German and Scandi- navian languages. Arguing that colour concepts are linguistic constructs through which speakers have learned to pay attention to their visual worlds, we trace the origin of the skin......This study explores the cultural semantics of colour words in the four urban, European communities of Munich, Berne, Aarhus, and Reykjavik, focussing on hautfarben (German), hutfarb (Bernese Swiss German), hudfarvet (Danish), and húðlitur (Icelandic), all of which can be translated as ‘skin...... coloured’. Unlike in English, where skin coloured has fallen out of use due to its racist semantic profile, these words are still widely present within the four communities. Using evidence from a referential colour naming task and semi-structured interviews, our study seeks to reveal the linguistic...

A familial factor in the development of colour agnosia.

Science.gov (United States)

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

2007-04-09

An important aspect of research into the link between genes and behaviour concerns the identification of familial determination. There is evidence for familial factors in selective deficits, such as developmental dyslexia and developmental prosopagnosia. Colour agnosia concerns a selective neuropsychological condition in which colour perception is intact, while the identification and naming of colour is disrupted. We recently demonstrated that this deficit can occur as a developmental deficit. Here, we show that there is a familial factor in the development of colour agnosia by reporting the colour processing abilities of the mother and the daughters of a man with developmental colour agnosia.

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.