8 research outputs found

    The Metric of Colour Space

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    Archaeometric Classification of Scattered Marble Fragments to Help the Reconstruction of Statues

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    A multi-technique approach combining petrographic, cathodoluminescence, and stable isotope analyses is commonly used in provenance studies of archaeological marbles. In the present paper, this characterization approach transcends provenance, and it is applied to the reconstruction of fragmented sculptures. The potential of this novel application of archaeometric measurements is illustrated with a case study consisting in 16 scattered marble fragments retrieved from a Roman villa (Els Munts) near Tarraco (presently Northeastern Spain). The samples were grouped taking into account their similarity in quantified parameters such as the cathodoluminescence color clusters and the stable carbon and oxygen isotopic ratios. The results permitted classification of the fragments into three groups corresponding to three different statues depicting Antinous (7 fragments), Minerva goddess (4 fragments), and an undetermined character (3 fragments). Two other fragments could not be ascribed to any particular statue. The archaeometric grouping provides arguments that can be used to confirm or refute archaeological hypotheses of statue reconstructions. © 2022 by the authors

    Bio-Physics Concept For Camera Vision Hypothesis Of Colour White

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    In the myriad of colours, black and white are strange colours to be discussed. Since black (the colour that one perceives) is not in the Electromagnetic (EM) spectrum, it is duly suggested that black is an interpretation of the brain in which the existing “no signal” concept is also discussed in the article. The same goes to the colour white, it is not in the EM spectrum too, so it is also duly proposed as an interpretation of the brain. The concept of white as combination of colour is also discussed in the article. It is insignificant to discuss about both these colours of their existence in the reflection of colour representation since their non-existent in EM spectrum is similar to the colour pink or magenta. There is a hypothesis (for white light colour theory test) at the end of this article, the authors welcome any scientists or engineers or researcher all over the world to assess, deliberate and prove the truth of this theory

    The subjective metric of remembered colors: A Fisher-information analysis of the geometry of human chromatic memory.

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    In order to explore the metric structure of the space of remembered colors, a computer game was designed, where players with normal color vision had to store a color in memory, and later retrieve it by selecting the best match out of a continuum of alternatives. All tested subjects exhibited evidence of focal colors in their mnemonic strategy. We found no concluding evidence that the focal colors of different players tended to cluster around universal prototypes. Based on the Fisher metric, for each subject we defined a notion of distance in color space that captured the accuracy with which similar colors where discriminated or confounded when stored and retrieved from memory. The notions of distance obtained for different players were remarkably similar. Finally, for each player, we constructed a new color scale, in which colors are memorized and retrieved with uniform accuracy

    Developing an artificial colour-sound association for musical composition

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    Some great composers - Messiaen, Scriabin, Liszt in exemplum - have been found to have an internal colour world that responds to music and characterises the way they experience and express music. Many of these artists, it could be strongly argued, had the neurological trait synaesthesia. The author, a non-synaesthete, creates a logical correspondence between colour and sound and uses it to explore the tonality of aesthetic colour combinations in nature and modern life. He argues that if the colour-sound practitioner is consistent in their colour-sound association, they can benefit in harmonic discoveries as the synaesthete does. It was found that the harmonies produced were strange, new tonalities that do not repeat in each octave but form something akin to macro-chords, shifting density in different registers. The author produced a series of short scores for small ensembles to explore the possible merits of drawing harmony in music from harmony in colour

    REFRESH : a new approach to modeling dimensional biases in perceptual similarity and categorization

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    Much categorization behavior can be explained by family resemblance: New items are classified by comparison with previously learned exemplars. However, categorization behavior also shows a variety of dimensional biases, where the underlying space has so-called “separable” dimensions: Ease of learning categories depends on how the stimuli align with the separable dimensions of the space. For example, if a set of objects of various sizes and colors can be accurately categorized using a single separable dimension (e.g., size), then category learning will be fast, while if the category is determined by both dimensions, learning will be slow. To capture these dimensional biases, almost all models of categorization supplement family resemblance with either rule-based systems or selective attention to separable dimensions. But these models do not explain how separable dimensions initially arise; they are presumed to be unexplained psychological primitives. We develop, instead, a pure family resemblance version of the Rational Model of Categorization (RMC), which we term the Rational Exclusively Family RESemblance Hierarchy (REFRESH), which does not presuppose any separable dimensions in the space of stimuli. REFRESH infers how the stimuli are clustered and uses a hierarchical prior to learn expectations about the variability of clusters across categories. We first demonstrate the dimensional alignment of natural-category features and then show how through a lifetime of categorization experience REFRESH will learn prior expectations that clusters of stimuli will align with separable dimensions. REFRESH captures the key dimensional biases and also explains their stimulus-dependence and how they are learned and develop

    Non-isometric colour similarity

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    This paper presents the findings obtained in an experimental study of metric underlying the perceptual colour space. Previous studies evidenced that, in tasks of evaluation of colour similarity, the subjects don't refer to the most general category of “colour”, but rather rely on the introduction of subordinate categories containing all variations of a colour. Besides, categories related to different colours can sometimes overlap. This forces to conclude that perception of colour variations is not isometric, but is rather weighed in different ways for different colours. In order to detect the metric of colour space we performed an experiment with multiple conditions within the subjects, designed to determine the form of the function that ties the independent variable (tonality of colour) with the dependent variable (similarity judgement). To each subject we presented simultaneously a pair of images, the target one and another differing from the target only for its colour (a suitable perturbation of the tonality). The subject task was to rate the similarity of the second image with the target. The frequency distribution of similarity judgments for each colour gave a qualitative description of how the different colours are represented at the cognitive level. We applied to the observed frequencies a unidimensional scaling procedure to obtain a precise measure of the distance between the variation steps for each colour. We were allowed to choose a single dimension because we limited the study only to the variation of tonality. The scaling was applied separately to each colour scale. The results showed that different colours were associated to different measure scales. Besides, once chosen a particular colour, its measure scale itself was depending on the direction of variation chosen for its tonality during the experimental presentation. We can conclude that the geometry of colour space looks very complicated and not reducible to familiar mathematical concepts
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