No / PURPOSE. This study examined the influence of stimulus chromaticity on simple reaction times (RTs) to determine the stage of chromatic processing that is most influential in their generation. METHODS. Simple RTs were measured in response to the cosinusoidally ramped onset of small, equiluminant, colored Gaussian spots. The chromaticity of these stimuli was varied, to modulate along a series of vectors in color space that included red-green (L-M) and blue-yellow (S-[L+M]) opponent axes. RESULTS. RTs are highly sensitive to small departures from subjective equiluminance. They are also dependent on stimulus chromaticity. The longest RTs are generated in response to equiluminant stimuli that isolate S-cone activity, whereas the shortest are generated by stimuli that modulate the L-M opponent axis. However, temporal processing differences are highly dependent on how the chromatic stimuli are scaled in relation to one another. The differences are reduced when scaling is based on detection threshold. The relationship between chromatic contrast and RT can be described by the modified Piéron equation RT = RT0 + k · C-1. CONCLUSIONS. Simple RTs generated in this study conform to the idea that they are largely determined by cone-opponency mechanisms. The use of cone contrast as a metric for scaling chromatic stimuli exaggerates differences between the temporal responsiveness of L-M and S-(L+M) opponency mechanisms.

Yes / Derivatives of fulgides have been shown to have interesting photochromic properties. We have synthesised a number of such derivatives and have found, in some cases, that crystals can be made to change colour on crushing, a phenomenon we have termed "tribochromism". We have studied a number of derivatives by X-ray crystallography, to see if the colour is linked to molecular structure or crystal packing, or both, and our structural results have been supported by calculation of molecular and lattice energies. A number of 5-dicyanomethylene-4-diphenylmethylene-3-disubstitutedmethylene-tetrahydrofuran-2 -one compounds have been prepared and structurally characterised. The compounds are obtained as yellow or dark red crystals, or, in one case, both. In two cases where yellow crystals were obtained, we found that crushing the crystals gave a deep red powder. Structure determinations, including those of the one compound which gave both coloured forms, depending on crystallisation conditions, showed that the yellow crystals contained molecules in which the structure comprised a folded conformation at the diphenylmethylene site, whilst the red crystals contained molecules in a twisted conformation at this site. Lattice energy and molecular conformation energies were calculated for all molecules, and showed that the conformational energy of the molecule in structure IIIa (yellow) is marginally higher, and the conformation thus less stable, than that of the molecule in structure IIIb (red). However, the van der Waals energy for crystal structure IIIa, is slightly stronger than that of structure IIIb - which may be viewed as a hint of a metastable packing preference for IIIa, overcome by the contribution of a more stabilising Coulomb energy to the overall more favourable lattice energy of structure IIIb. Our studies have shown that the crystal colour is correlated with one of two molecular conformations which are different in energy, but that the less stable conformation can be stabilised by its host crystal lattice. Graphical abstractGraphical representation of the structural and colour change in the tribochromic compound (III).

Yes / Motion in depth (MID) can be cued by high-resolution changes in binocular disparity over time (CD), and low-resolution interocular velocity differences (IOVD). Computational differences between these two mechanisms suggest that they may be implemented in visual pathways with different spatial and temporal resolutions. Here, we used fMRI to examine how achromatic and S-cone signals contribute to human MID perception. Both CD and IOVD stimuli evoked responses in a widespread network that included early visual areas, parts of the dorsal and ventral streams, and motion-selective area hMT+. Crucially, however, we measured an interaction between MID type and chromaticity. fMRI CD responses were largely driven by achromatic stimuli, but IOVD responses were better driven by isoluminant S-cone inputs. In our psychophysical experiments, when S-cone and achromatic stimuli were matched for perceived contrast, participants were equally sensitive to the MID in achromatic and S-cone IOVD stimuli. In comparison, they were relatively insensitive to S-cone CD. These findings provide evidence that MID mechanisms asymmetrically draw on information in precortical pathways. An early opponent motion signal optimally conveyed by the S-cone pathway may provide a substantial contribution to the IOVD mechanism. / Supported by the Biotechnology and Biological Sciences Research Council Grants BB/M002543/1 (to A.R.W.), BB/M001660/1 (to J.M.H.), and BB/M001210/1 (to M.B.). / Research Development Fund Publication Prize Award winner, May 2019.

Biologically inspired logarithmic CMOS sensors offer high dynamic range imaging capabilities without the difficulties faced by linear imagers. By compressing dynamic range while encoding contrast information, they mimic the human visual system’s response to photo stimuli in fewer bits than those used in linear sensors. Despite this prospect, logarithmic sensors suffer poor image quality due to illumination dependent fixed pattern noise (FPN), making individual pixels appear up to 100 times brighter or darker. This thesis is primarily concerned with alleviating FPN in logarithmic imagers in a simple and convenient way while undertaking a system approach to its origin, distribution and effect on the quality of monochrome and colour images, after FPN correction. Using the properties of the Human visual system, I propose to characterise the errors arising from FPN in a perceptually significant manner by proposing an error measure, never used before. Logarithmic operation over a wide dynamic range is first characterised using a new model; yi j =aj +bj ln(exp sqrt(cj +djxi)−1), where yi j is the response of the sensor to a light stimulus xi and aj, bj, cj and dj are pixel dependent parameters. Using a proposed correction procedure, pixel data from a monochromatic sensor array is FPN corrected to approximately 4% error over 5 decades of illumination even after digitisation - accuracy equivalent to four times the human eyes ability to just notice an illumination difference against a uniform background. By evaluating how error affects colour, the possibility of indiscernible residual colour error after FPN correction, is analytically explored using a standard set of munsell colours. After simulating the simple FPN correction procedure, colour quality is analysed using a Delta E76 perceptual metric, to check for perceptual discrepancies in image colour. It is shown that, after quantisation, the FPN correction process yields 1−2 Delta E76 error units over approximately 5 decades of illumination; colour quality being imperceptibly uniform in this range. Finally, tone-mapping techniques, required to compress high dynamic range images onto the low range of standard screens, have a predominantly logarithmic operation during brightness compression. A new Logr'Gb' colour representation is presented in this thesis, significantly reducing computational complexity, while encoding contrast information. Using a well-known tone mapping technique, images represented in this new format are shown to maintain colour accuracy when the green colour channel is compressed to the standard display range, instead of the traditional luminance channel. The trade off between colour accuracy and computation in this tone mapping approach is also demonstrated, offering a low cost alternative for applications with low display specifications.

This project report offers insight into my research, creative process and work during my two-year Master in visual communication at Konstfack, Stockholm.Clean: Not the Monochrome, Universal and Neutral Modernism You Expect is the published culmination of a period of visual research highlighting Modernism — Modernist (graphic) design and architecture to be precise — as a power structure by uncovering its connections to colonialism and design authoritarianism through misperception, whiteness, exclusive practicing and imposition.The book uses intersections of visual material, personal experience and theory to deconstruct the inheritance of the creative practitioner working in the realm of Modernism as well as its presumed neutrality.

A Esclerose Múltipla (EM) é uma doença inflamatória autoimune caracterizada por desmielinização e degeneração do sistema nervoso central (SNC) duas a três vezes mais frequente em mulheres. A etiologia da EM é dividida em dois subtipos principais: o tipo remitente-recorrente (EMRR) mais comum, caracterizado por dois ou mais episódios de agravamento dos sintomas que envolvem diferentes locais do SNC, separados por pelo menos 1 mês e remisão dos sintomas e o tipo progressivo é a forma menos comum, caracterizada por um contínuo agravamento dos sintomas desde o início geralmente sem recaídas claras ou remissões. A presente pesquisa teve por objetivo avaliar o comprometimento da visão de cores e de sua relação com perdas de atenção, memória visual imediata, memória visual tardia, memória operacional e funções executivas dos portadores de esclerose múltipla tipo remitente recorrente. Método: participaram 41 pacientes com esclerose múltipla de idades entre 20 e 58 anos (35,4±12,2) e 37 controles com idade (34,7±12,1) e escolaridade semelhante. A discriminação de cores foi avaliada com o Cambridge Colour Test (CCT) e a avaliação de funções neuropsicológicas foram utilizados subtestes da bateria Cambridge Neuropsychological Testing Automated Battery (CANTAB) - Pattern Recognition Memory, Spatial Span, Spatial Recognition Memory, Information Sampling Task, Stop Signal Task e Rapid Information Processing; Escalas de Depressão e Ansiedade de Beck e Escala de Determinação Funcional da Qualidade de vida (DEFU). Resultados: A visão de cores está prejudicada de forma difusa em 24% dos pacientes com esclerose múltipla, tanto em pacientes com histórico de neurite óptica quando em pacientes que não tiveram neurite óptica. Na parte cognitiva, os pacientes demonstraram lentidão em executar as tarefas, comprometimento na atenção, na memória visual de curto e longo prazo, na memória operacional, na memória visuoespacial, além de lentidão no processamento de informações. Há uma relação entre alterações na visão de cores e alterações de memória visual somente em testes em que os estímulos são complexos e com inúmeros detalhes / Multiple sclerosis (MS) is an autoimmune inflammatory disease characterized by demyelination and central nervous system (CNS) degeneration. It is two times more frequent in women. It can be presented in two subtypes: the relapsing-remitting (RR), most common type, characterized by two or more episodes of focal disorders in different sites of the CNS, and remission of the symptoms; and the progressive subtype, less common, characterized by a continuous worsening of the symptoms, since the beginning, usually with no remissions. The present research evaluated color vision impairment and its relationship to attention loss, short-term memory, long-term memory, working memory and executive function in patients with the relapsing-remitting MS type. Methods: 41 patients with multiple sclerosis (20 to 58 years, 35.4 ± 12.2 in average) and 37 controls matched to age (34.7 ± 12.1 in average) and years of education participated of the study. Color vision was tested using the Cambridge Colour Test (CCT) and the neuropsychological assessment was performed using tests of the Cambridge Neuropsychological Testing Automated Battery (CANTAB) - Pattern Recognition Memory, Spatial Span, Spatial Recognition Memory, Information Sampling Task, Stop Signal Task, Rapid Information Processing the Beck Depression and Anxiety Inventories and the Functional Assessment of Multiple Sclerosis quality of life instrument. Results: Color vision was diffusely impaired in 24% of the MS patients, with or with no history of optic neuritis. Patients also showed a delay during the tasks execution, impairment in attention, short and long-term visual memory and working memory, and slowness in the information processing. There was a relationship between color vision loss and visual memory impairment, but only in tests with complex and highly detailed stimuli

<p>This thesis examines usage of English colour terms in context, based on an extensive computerised text corpus, the Bank of English. It describes the ways in which English colour terms may be used to refer to nuances outside their normal area of designation and to attributes outside the colour domain. Usage patterns are analysed on three different levels: with regard to the overall frequency of occurrences, nominal domains and individual tokens, respectively. </p><p>Cognitive linguistics supplies the theoretical framework employed in the analyses of the observed patterns. The study identifies three types of usage where colour terms refer to peripheral colour nuances or to concepts outside the colour domain: classifying, figurative and marked usage. </p><p>When a colour term has a classifying function, it can be used outside the normal area of designation. This usage is analysed as a type of reference-point construction where a term referring to a salient point in the colour domain is used to subcategorise an entity whose actual colour may be only a peripheral member of the category named by the colour term. An analysis of the OED and the Bank of English shows that this type of usage is primarily restricted to a few of the most salient basic terms. </p><p>This study points to the close affinities between classifying and figurative usage. Figurative expressions of colour terms frequently have a classifying function. I argue that figurative meanings are derived through two types of metonymy: +SALIENT ATTRIBUTE FOR OBJECT+ and +SALIENT CONCRETE ATTRIBUTE FOR SALIENT ABSTRACT ATTRIBUTE+. </p><p>Marked usage arises when specific colour terms are used in nominal domains where the specificity is not expected. This phenomenon is consequently confined to non-basic colour terms. </p><p>On the basis of the established patterns of usage and the frequency of occurrences, this thesis suggests that the colour category may be analysed as a radial category, with the basic colour terms forming the centre. </p>

This thesis examines usage of English colour terms in context, based on an extensive computerised text corpus, the Bank of English. It describes the ways in which English colour terms may be used to refer to nuances outside their normal area of designation and to attributes outside the colour domain. Usage patterns are analysed on three different levels: with regard to the overall frequency of occurrences, nominal domains and individual tokens, respectively. Cognitive linguistics supplies the theoretical framework employed in the analyses of the observed patterns. The study identifies three types of usage where colour terms refer to peripheral colour nuances or to concepts outside the colour domain: classifying, figurative and marked usage. When a colour term has a classifying function, it can be used outside the normal area of designation. This usage is analysed as a type of reference-point construction where a term referring to a salient point in the colour domain is used to subcategorise an entity whose actual colour may be only a peripheral member of the category named by the colour term. An analysis of the OED and the Bank of English shows that this type of usage is primarily restricted to a few of the most salient basic terms. This study points to the close affinities between classifying and figurative usage. Figurative expressions of colour terms frequently have a classifying function. I argue that figurative meanings are derived through two types of metonymy: +SALIENT ATTRIBUTE FOR OBJECT+ and +SALIENT CONCRETE ATTRIBUTE FOR SALIENT ABSTRACT ATTRIBUTE+. Marked usage arises when specific colour terms are used in nominal domains where the specificity is not expected. This phenomenon is consequently confined to non-basic colour terms. On the basis of the established patterns of usage and the frequency of occurrences, this thesis suggests that the colour category may be analysed as a radial category, with the basic colour terms forming the centre.

Utifrån arbetsmodellen Learning study, med variationsteorin som utgångspunkt har forskning genomförts i två klasser i Sverige med syftet att försöka identifiera kritiska aspekterna för elever i årskurs nio inom ämnesområdet det vita ljuset och dess färgspektrum. Studien är en vidareutveckling av en tidigare genomförd studie i Hong Kong och har därför även haft till syfte att undersöka om de identifierade kritiska aspekterna är generaliserbara från en skolkontext till en annan kontext. Den svenska skolan styrs nationellt utifrån styrdokument, skollag, läroplan och kursplan för skolämnet och läraren har även riktlinjer för att få en yrkesetisk förankring. Dessa delar är viktiga att läraren tar i beaktning inför planering av undervisningen. Elevernas bakgrund och förkunskaper i ämnet är av stor vikt för läraren att ta hänsyn till för att de ska kunna ta till sig undervisningen om det som läraren har tänkt att de ska lära sig. I denna studie kunde åtta kritiska aspekter identifieras i de två klasser som undersökningen genomfördes i. Fem av de kritiska aspekterna var redan identifierade i Hong Kong. Slutsatsen är att de kritiska aspekter som identifierats i en kontext också är giltiga i en annan. Som helhet fick forskarna insikten om att Learning study som arbetsmodell och variationsteorin som vägledande princip vid planering av undervisning, kan leda till ett rikare lärande både för eleverna, men även för lärarna som deltar i forskningen. / The Swedish school system is governed on the basis of national policy documents; school law, curriculum and the syllabus for the school subject. The teacher also have guidelines to follow to get a professional ethical foundation and needs to take this and the students' backgrounds and prior knowledge of the subject into account before planning a lesson. How can this be done with one model? This study shows how a Learning study can be used together with the theory of variation as a guideline to richer the learning for pupils in the ninth grade, in two Swedish classes. One of the intentions of this study was to try to identify critical aspects about the learning object: the colour of light. This study is a refinement of a previous study done in Hong Kong and has also been designed to examine if critical aspects can be transferred from one school context to another context. In this study eight critical aspects where identified in the two classes that the survey was conducted in. Five of them where already identified in the study from Hong Kong. The conclusion is that critical aspects are generalized, not only between classes in Sweden, but also between different countries, even if it is from a third grade in Hong Kong to a ninth grade in Sweden. Learning study, as a model, and the theory of variation, as a guiding principle, can lead to a richer learning both for the pupils, but also for the teachers that participate in the research.

<p>Utifrån arbetsmodellen Learning study, med variationsteorin som utgångspunkt har forskning genomförts i två klasser i Sverige med syftet att försöka identifiera kritiska aspekterna för elever i årskurs nio inom ämnesområdet det vita ljuset och dess färgspektrum. Studien är en vidareutveckling av en tidigare genomförd studie i Hong Kong och har därför även haft till syfte att undersöka om de identifierade kritiska aspekterna är generaliserbara från en skolkontext till en annan kontext.</p><p>Den svenska skolan styrs nationellt utifrån styrdokument, skollag, läroplan och kursplan för skolämnet och läraren har även riktlinjer för att få en yrkesetisk förankring. Dessa delar är viktiga att läraren tar i beaktning inför planering av undervisningen. Elevernas bakgrund och förkunskaper i ämnet är av stor vikt för läraren att ta hänsyn till för att de ska kunna ta till sig undervisningen om det som läraren har tänkt att de ska lära sig.</p><p>I denna studie kunde åtta kritiska aspekter identifieras i de två klasser som undersökningen genomfördes i. Fem av de kritiska aspekterna var redan identifierade i Hong Kong. Slutsatsen är att de kritiska aspekter som identifierats i en kontext också är giltiga i en annan. Som helhet fick forskarna insikten om att Learning study som arbetsmodell och variationsteorin som vägledande princip vid planering av undervisning, kan leda till ett rikare lärande både för eleverna, men även för lärarna som deltar i forskningen.</p> / <p>The Swedish school system is governed on the basis of national policy documents; school law, curriculum and the syllabus for the school subject. The teacher also have guidelines to follow to get a professional ethical foundation and needs to take this and the students' backgrounds and prior knowledge of the subject into account before planning a lesson. How can this be done with one model?</p><p>This study shows how a Learning study can be used together with the theory of variation as a guideline to richer the learning for pupils in the ninth grade, in two Swedish classes. One of the intentions of this study was to try to identify critical aspects about the learning object: the colour of light. This study is a refinement of a previous study done in Hong Kong and has also been designed to examine if critical aspects can be transferred from one school context to another context.</p><p>In this study eight critical aspects where identified in the two classes that the survey was conducted in. Five of them where already identified in the study from Hong Kong. The conclusion is that critical aspects are generalized, not only between classes in Sweden, but also between different countries, even if it is from a third grade in Hong Kong to a ninth grade in Sweden. Learning study, as a model, and the theory of variation, as a guiding principle, can lead to a richer learning both for the pupils, but also for the teachers that participate in the research.</p>