40 research outputs found

    A Multiple-Systems Approach in the Symbolic Modelling of Human Vision

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    For most of the thirty years or so of machine vision research, activity has been concentrated mainly in the domain of metric-based approaches: there has been negligible attention to the psychological factors in human vision. With the recent resurgence of interest in neural systems, that is now changing. This thesis discusses relevant aspects of basic visual neuroanatomy, and psychological phenomena, in an attempt to relate the concepts to a model of human vision and the prospective goals of future machine vision systems. It is suggested that, while biological vision is complex, the underlying mechanisms of human vision are more tractable than is often believed. We also argue here that the controversial subject of direct vision plays a crucial role in natural vision, and we attempt to relate this to the model. The recognition of massive parallelism in natural vision has led to proposals for emulating aspects of neural networks in technology. The systems model developed in this work demonstrates software-simulated cellular automata (CAs) in the role of mainly low-level image processing. It is shown that CAs are able to efficiently provide both conventional and neurally-inspired vision functions. The thesis also discusses the use of Prolog as the means of realising higher level image understanding. The symbolic processing developed is basic, but is nevertheless sufficient for the purposes of the present. demonstrations. Extensions to the concepts can be easily achieved. The modular systems approach adopted blends together several ideas and processes, and results in a more robust model of human vision that is able to translate a noisy real image into an accessible symbolic form for expert-domain interpretation

    Active modelling of virtual humans

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    This thesis provides a complete framework that enables the creation of photorealistic 3D human models in real-world environments. The approach allows a non-expert user to use any digital capture device to obtain four images of an individual and create a personalised 3D model, for multimedia applications. To achieve this, it is necessary that the system is automatic and that the reconstruction process is flexible to account for information that is not available or incorrectly captured. In this approach the individual is automatically extracted from the environment using constrained active B-spline templates that are scaled and automatically initialised using only image information. These templates incorporate the energy minimising framework for Active Contour Models, providing a suitable and flexible method to deal with the adjustments in pose an individual can adopt. The final states of the templates describe the individual’s shape. The contours in each view are combined to form a 3D B-spline surface that characterises an individual’s maximal silhouette equivalent. The surface provides a mould that contains sufficient information to allow for the active deformation of an underlying generic human model. This modelling approach is performed using a novel technique that evolves active-meshes to 3D for deforming the underlying human model, while adaptively constraining it to preserve its existing structure. The active-mesh approach incorporates internal constraints that maintain the structural relationship of the vertices of the human model, while external forces deform the model congruous to the 3D surface mould. The strength of the internal constraints can be reduced to allow the model to adopt the exact shape of the bounding volume or strengthened to preserve the internal structure, particularly in areas of high detail. This novel implementation provides a uniform framework that can be simply and automatically applied to the entire human model

    Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

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    The papers from the symposium are presented. Emphasis is placed on human factors engineering and space environment interactions. The technical areas covered in the human factors section include: satellite monitoring and control, man-computer interfaces, expert systems, AI/robotics interfaces, crew system dynamics, and display devices. The space environment interactions section presents the following topics: space plasma interaction, spacecraft contamination, space debris, and atomic oxygen interaction with materials. Some of the above topics are discussed in relation to the space station and space shuttle

    Analysis and resynthesis of polyphonic music

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    This thesis examines applications of Digital Signal Processing to the analysis, transformation, and resynthesis of musical audio. First I give an overview of the human perception of music. I then examine in detail the requirements for a system that can analyse, transcribe, process, and resynthesise monaural polyphonic music. I then describe and compare the possible hardware and software platforms. After this I describe a prototype hybrid system that attempts to carry out these tasks using a method based on additive synthesis. Next I present results from its application to a variety of musical examples, and critically assess its performance and limitations. I then address these issues in the design of a second system based on Gabor wavelets. I conclude by summarising the research and outlining suggestions for future developments

    Feelings as direct information of our action capabilities

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    Tese de Doutoramento em Psicologia na área de especialidade Psicologia Cognitiva apresentada ao ISPA - Instituto UniversitárioA percepção destinada a guiar a ação é um processo ativo e contínuo em que os atores ressoam suas características corporais para medir constantemente as relevantes propriedades físicas do meio ambiente. Ao invés de serem guiadas por nossas crenças, nossas ações são guiadas por affordances. Ou seja, as oportunidades de ação que emergem do sistema atorambiente e que são limitadas pelas nossas capacidades de ação - os limites dinâmicos do nosso corpo que estão intrinsecamente relacionados aos estados morfológicos, fisiológicos e psicológicos do corpo. Aqui analisamos as evidências que demonstram que somos sensíveis e que acessamos informações sobre nossos limites de ação para antecipar ou realizar ações reais. Nosso objetivo é entender como os atores são informados sobre seus próprios limites de ação quando uma oportunidade de ação emerge. Por exemplo, como os atores que rastreiam visualmente uma bola a reduzir o tamanho são informados de que o tamanho da bola se encaixa (ou não) nas mãos quando estimando a agarrabilidade da bola? Nesta tese abordamos diretamente a hipótese de que os sentimentos que surgem como parte de qualquer processo cognitivo são integrados como informações não-visuais sobre nossos limites de ação. Assumindo a perspectiva da incorporação (a integração da informação sensório-motora como moldando e integrando a cognição), combinamos dois quadros teóricos distintos e relevantes para investigar nossa hipótese: a teoria das affordances (Gibson, 1979) e a abordagem do sentimento-como-informação para o julgamento e tomada de decisão (Clore, 1992; Schwarz & Clore, 1983). A primeira teoria torna claro como as capacidades de ação estão intrínsecamente relacionadas à nossa percepção do entorno em termos de possibilidades de ação. A segunda abordagem mostra como sentimentos positivos e negativos informam o processamento em termos de custos e benefícios quando na interação com o contexto. Em três artigos, testamos se os sentimentos informam nossas capacidades de ação. No primeiro artigo, examinamos se os casos anedóticos que sugerem a decisão dos atletas com base em sentimentos apresetam suporte fenomenológico. Em um estudo de campo que aplicou o método correlacional, encontramos evidências de que peritos jogadores de futsal se reconhecem como confiando em sentimentos em contraposição à experiência de pensamento deliberativo, principalmente em situações de jogo categorizadas por eles como imprevisíveis, complexas e dinâmicas. No segundo trabalho, iniciamos nossa série de investigações de laboratório, primeiro rastreando a atividade muscular do corrugador e do zigomático (índice de experiência afetiva negativa e positiva) numa configuração de capacidade de ação. Os resultados indicam que uma experiência de negatividade parece ser subjacente às estimativas baseadas em ações, uma vez que o músculo corrugador é ativado somente quando os atores precisam realizar acoplamento perceptual-motor para eventos dinâmicos, mas não quando eles apenas apreendem os mesmos eventos. Em adição, uma manipulação subliminar de primação afetiva indica que esse resultado não se deve apenas ao processo atencional. No terceiro artigo, replicamos a manipulação afetiva e, mais uma vez, descobrimos que ela promove mudanças confiáveis nos limites de ação percebidos pelos participantes. Isso ocorreu especialmente quando restringimos o tempo e os movimentos do corpo. Juntos, esses achados sugerem que os sentimentos têm um papel nas estimativas baseadas em ações e em nossos limites de ação percebidos. Estes dados estendem a abordagem do sentimento-como-informação aos julgamentos que acoplam percepção-ação. Estudos futuros devem esclarecer melhor a natureza desse papel.ABSTRACT : Perception intended to guide action is an active and ongoing process in which actors resonate their body features to constantly gauging relevant physical properties of the environment. Rather than by beliefs our actions are guide by affordances. That is, opportunities for action emerge from the actor-environment system and which are constrained by our action capabilities – the dynamic boundaries of our body that are intrinsically related to morphological, physiological, and psychological states. Here we review evidence demonstrating that we are sensitive and accede information regards our action boundaries to anticipate or perform real actions. Our aim is to understand how actors are informed about their own action boundaries when an affordance is made emergent. For instance, how actors visually tracking a shrinking ball are informed that the ball size fits its hands when estimating grasping? We directly approach the hypothesis that feelings arising as part of any cognitive processes are integrating as non-visual information regards our action boundaries. Assuming an embodiment perspective (the integration of sensorimotor information as shaping and taking part on cognition) we approach our hypothesis by merging two distinct and relevant theoretical frameworks: the theory of affordances (Gibson, 1979) and the feeling-as-information approach for judgment and decision making (Clore, 1992; Schwarz & Clore, 1983). The first theory turns clear how action capabilities are intrinsic related to perception of surrounding in terms of action possibilities. The second shows how positive and negative feelings inform processing. Across three papers we test if feelings inform our action capabilities. In the first paper, we examine if the anecdotal cases suggesting athletes’ decision based on feelings had phenomenological support. In a field study applying correlational method we found evidence that expert futsal players indeed acknowledge themselves as relying on feelings in contraposition to deliberative thinking experience, mostly in game-situations categorized by them as unpredictable, complex and dynamic. In the second paper, we start our series of lab investigations, by first tracking the muscular activity of the corrugator and the zygomatic (respectively index of negative and positive affective experience) in action capabilities setting. Results indicate that a negativity experience seems underlying the action-based estimations, since the corrugator is activated only when actors need to perform perceptual-motor coupling to dynamic events and not when they merely apprehend the same events. In addition, a subliminal affective priming manipulation indicates that this is not merely due to attentional process. In the third paper, we replicated the affective priming manipulation and once more we found it promotes reliable changes in the perceived action boundaries of the participants. This occurring, especially when we constrained time and body movements. Taken together these finding suggest that feelings have a role in action-based estimations and in our perceived action boundaries. This data extends the feeling-asinformation approach to judgments coupling action-perception. Future studies should better clarify the nature of this role

    Proceedings of the NASA Conference on Space Telerobotics, volume 3

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    The theme of the Conference was man-machine collaboration in space. The Conference provided a forum for researchers and engineers to exchange ideas on the research and development required for application of telerobotics technology to the space systems planned for the 1990s and beyond. The Conference: (1) provided a view of current NASA telerobotic research and development; (2) stimulated technical exchange on man-machine systems, manipulator control, machine sensing, machine intelligence, concurrent computation, and system architectures; and (3) identified important unsolved problems of current interest which can be dealt with by future research

    Establishing criteria to evaluate reading programmes intended for intermediate to advanced level ESL learners in South African schools

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    This study set out to formulate criteria for evaluating reading comprehension materials intended for ESL readers in~high schools in South Africa. Such criteria may help teachers in selecting textbooks which have theoretically-informed reading programmes. It was first necessary, therefore, to isolate those points from reading comprehension theory that could be included in the criteria. Secondly, other checklists/criteria in ESL evaluation were examined to identify a framework within which to work. In the first draft, questions to be included in the criteria/checklist were formulated using justification from reading comprehension theory. A focus group technique was then used to obtain preliminary feedback on the usability of the checklist. Suggestions from the focus group were used to revise the cri teria . A final checklist was prepared which teachers could use as an instrument to evaluate reading comprehension programmes in language textbooks

    Nonlinear acoustics of water-saturated marine sediments

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