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Resultados de la búsqueda223 resultados

  • Space-frequency quantization using Directionlets

    Velisavljevic, V.; Beferull-Lozano, B.; Vetterli, M.

    (2007). Article

    In our previous work we proposed a construction of critically sampled perfect reconstruction transforms with directional vanishing moments (DVMs) imposed in the corresponding basis functions along different directions, called directionlets. Here, we combine the directionlets with the space-frequency quantization (SFQ) image compression method, originally based on the standard two-dimensional (2-D) wavelet transform (WT). We show that our new compression method outperforms the standard SFQ as well as the state-of-the-art compression methods, like SPIHT and JPEG-2000, in terms of the quality of compressed images, especially in a low-rate compression regime. We also show that the order of...

    In our previous work we proposed a construction of critically sampled perfect reconstruction transforms with directional vanishing moments (DVMs) imposed in the corresponding basis functions along different directions, called directionlets. Here, we combine the directionlets with the space-frequency quantization (SFQ) image compression method, originally based on the standard two-dimensional (2-D) wavelet transform (WT). We show that our new compression method outperforms the standard SFQ as well as the state-of-the-art compression methods, like SPIHT and JPEG-2000, in terms of the quality of compressed images, especially in a low-rate compression regime. We also show that the order of computational complexity remains the same, as compared to the complexity of the standard SFQ algorithm.

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  • Space-Frequency Quantization for Image Compression using Directionlets

    Velisavljevic, V.; Beferull-Lozano, B.; Vetterli, M.

    (2007). Article

  • 11th International Conference on Computing and Decisión Making in Civil and Building Engineering : VALLE®: A highway design system in a virtual reality environment

    Bosch,Carlos; Ballester, f.; Otero, Cesar; Fernández, Marcos; Coma, Inmaculada; Togores, Reinaldo; Pérez, M. Antonia

    (2006). Article

    Herramienta VALLE para la visualización interactiva de carreteras. Approximately 3 years ago, the Spanish company DRAGADOS undertook the creation of a Highway Design program completely integrated in a Virtual Reality environment. Throughout the first months of the year 2006, the version 1.0 of VALLE® (Virtual roAd modeLLEr) is being implanted in the Company. DRAGADOS’ intention was to merge in VALLE® the technical and interactive capacities of a Civil Engineering Computer Aided Design application (like InRoads, Civil 3D, etc.) with the graphic and realistic capacities of Virtual Representation software (such as Virtual Map, RDV or similar) so that the user could directly test modifications...

    Herramienta VALLE para la visualización interactiva de carreteras. Approximately 3 years ago, the Spanish company DRAGADOS undertook the creation of a Highway Design program completely integrated in a Virtual Reality environment. Throughout the first months of the year 2006, the version 1.0 of VALLE® (Virtual roAd modeLLEr) is being implanted in the Company. DRAGADOS’ intention was to merge in VALLE® the technical and interactive capacities of a Civil Engineering Computer Aided Design application (like InRoads, Civil 3D, etc.) with the graphic and realistic capacities of Virtual Representation software (such as Virtual Map, RDV or similar) so that the user could directly test modifications of horizontal alignments, profiles, sections or other elements in an interactive and realistic way. The ability of editing the road layout in a realistic representation of the environment makes VALLE® a valuable aid in the decision making process related to highway design.

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  • Sixth IASTED International Conference. Visualization, Imaging and Image Processing: An authoring tool for driving simulation experiments based on configurable components

    Coma, Inmaculada; Fernández, Marcos; Bayarri, Salvador

    (2006). Article

    Herramienta para el diseño de experimento en simulación de conducción. Designing a driving simulator for experimental or driver training purposes requires creating a number of exercises or scenarios to take measurements of driver’s performance. Those scenarios are difficult to generate. The reason for this complexity is that a database with different related layers must be created and combined. These layers are the visual information (roads and environment), the network topology and logical lanes, and the elements with dynamic behaviour (cars, lights and virtual actors). Some of these dynamic elements have an autonomous behaviour while others need to be controlled to produce repeatable...

    Herramienta para el diseño de experimento en simulación de conducción. Designing a driving simulator for experimental or driver training purposes requires creating a number of exercises or scenarios to take measurements of driver’s performance. Those scenarios are difficult to generate. The reason for this complexity is that a database with different related layers must be created and combined. These layers are the visual information (roads and environment), the network topology and logical lanes, and the elements with dynamic behaviour (cars, lights and virtual actors). Some of these dynamic elements have an autonomous behaviour while others need to be controlled to produce repeatable events. In this paper an approach for generation and control of simulation scenarios, based on configurable components and interfaces to configure them, is introduced. One advantage of this approach is the use of a unique tool for the whole design process (both static and dynamic scenarios) providing graphic interfaces with direct manipulation that make easier the development of simulation applications.

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  • III Congreso internacional de Ciudad y Territorio Virtual: Integración de las técnicas de realidad virtual en el proceso de diseño y revisión de proyectos de infraestructuras viarias: VALLE.

    Fernández, Marcos; Coma, Inmaculada; Otros

    (2006). Article

    Herramienta VALLE para el diseño de estructuras viarias y carreteras el apoyo de las técnicas de visualización 3D. Desde hacia varios años se ha hecho evidente el interés que tienen en el diseño de estructuras viarias y carreteras el apoyo de las técnicas de visualización 3D para tener una idea tanto del aspecto final de un proyecto concreto e incluso poder evaluar su impacto ambiental y estético. Son diversos los paquetes (VirtualMap, RDV u otros similares) que incluyen exportadores o visualizadores de este tipo. No obstante en todos los casos la aparición de las técnicas 3D en algunos casos es para generar simplemente un video de presentación y en otros casos algún vuelo que aunque...

    Herramienta VALLE para el diseño de estructuras viarias y carreteras el apoyo de las técnicas de visualización 3D. Desde hacia varios años se ha hecho evidente el interés que tienen en el diseño de estructuras viarias y carreteras el apoyo de las técnicas de visualización 3D para tener una idea tanto del aspecto final de un proyecto concreto e incluso poder evaluar su impacto ambiental y estético. Son diversos los paquetes (VirtualMap, RDV u otros similares) que incluyen exportadores o visualizadores de este tipo. No obstante en todos los casos la aparición de las técnicas 3D en algunos casos es para generar simplemente un video de presentación y en otros casos algún vuelo que aunque interactivo no permite sino ver y no interactuar con el diseño en cuestión. Sin embargo, en determinados casos, como la revisión de obras o la discusión de proyectos de gran envergadura, seria interesante que la representación 3D interactivo o modelo de realidad virtual permitiese la edición sobre dicho modelo de los diseños de la carretera o infraestructura viaria en cuestión. Siguiendo esta reflexión hace ya tres años dragados se planteo buscar una herramienta que integrase las posibilidad de la edición de carreteras (aunque de forma limitada) con un entorno de realidad virtual 3d interactivo. Fruto de esta búsqueda fue la formación de un grupo de investigación y desarrollo formado por personal de DRAGADOS, la escuela de ingenieros de caminos de la Universidad de Cantabria y el grupo ARTEC del Instituto de Robótica de la Universitat de València. Este equipo con experiencia contrastada tanto en el campo de la ingeniería civil (Universidad de Cantabria) como en la realidad virtual (artec) ha desarrollado el paquete VALLE® para cubrir los requerimiento anteriormente citados.

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  • 2nd world autism congress & exhibition'06: exploring the advantages of augmented reality for intervention in asd

    Herrera, Gerardo; Jordan, Rita; Gimeno, Jesús

    (2006). Article

    Full article.

    Research and practice have demonstrated that both visual and computer mediation of learning is very facilitatory in autism spectrum disorders (ASD). Virtual Reality (VR) has extended and enhanced those benefits but still leaves some more severely affected individuals unable to generalise their learning to new situations. Augmented Reality (AR) Technologies offer new opportunities for providing visual information to people with autism in real (although augmented) situations and have the potential to further facilitate learning. In this paper we explore some ways in which AR can augment the reality seen by the individual with autism that, as we suggest, can be of high educational benefit. We...

    Research and practice have demonstrated that both visual and computer mediation of learning is very facilitatory in autism spectrum disorders (ASD). Virtual Reality (VR) has extended and enhanced those benefits but still leaves some more severely affected individuals unable to generalise their learning to new situations. Augmented Reality (AR) Technologies offer new opportunities for providing visual information to people with autism in real (although augmented) situations and have the potential to further facilitate learning. In this paper we explore some ways in which AR can augment the reality seen by the individual with autism that, as we suggest, can be of high educational benefit. We suggest its use in pretend play training; regarding help on the distinction of the self from others; for augmenting communication and social understanding; for one’s own emotional awareness; for improving attention patterns; for teaching object permanence and for concept development through what we call ‘superimposed pictograms’.

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  • Interacción'06: ENSISAM, un entorno de simulación de situaciones de salvamento marítimo.

    Gimeno, Jesús; Casas, Sergio; Pérez, Manuel; Fernández, Marcos; Coma, Inmaculada

    (2006). Article

    Articulo completo.

    La necesidad de instrucción y evaluación de procedimientos de salvamento marítimo y la imposibilidad de realizar estas tareas en condiciones reales, se puede resolver mediante el uso de técnicas de simulación inmersiva. Este es el caso del entorno ENSISAM, donde además de utilizar técnicas avanzadas de simulación gráfica en tiempo real, se han desarrollado y aplicado elementos de interacción multimodales, así como nuevos dispositivos de diseño propio, creados a partir de las necesidades específicas de los usuarios, como el guante inalámbrico de realidad virtual Thimble-Glove.

  • Interactive Terrain Simulation and Force Distribution Models in Sand Piles

    Pla Castells, M.; García Fernández, I.; Martínez Durá, R. J.

    (2006). Article

    Lecture Notes on Computer Science, 2006, 4173, 392-401 This paper presents an application of Cellular Automata in the field of dry Granular Systems modelling. While the study of granular systems is not a recent field, no efficient models exist, from a computational point of view, in classical methodologies. Some previous works showed that the use of Cellular Automata is suitable for the development of models that can be used in real time applications. This paper extends the existing Cellular Automata models in order to make them interactive. A model for the reaction to external forces and a pressure distribution model are presented and analyzed, with numerical examples and simulations.

  • Low-rate reduced complexity Image compression using Directionlets

    Velisavljevic, V.; Beferull-Lozano, B.; Vetterli, M.; Dragotti, P. L.

    (2006). Article

    The standard separable two-dimensional (2-D) wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to capture efficiently one-dimensional (1-D) discontinuities, like edges and contours, that are anisotropic and characterized by geometrical regularity along different directions. In our previous work, we proposed a construction of critically sampled perfect reconstruction anisotropic transform with directional vanishing moments (DVM) imposed in the corresponding basis functions, called directionlets. Here, we show that the computational complexity of our transform is comparable to the...

    The standard separable two-dimensional (2-D) wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to capture efficiently one-dimensional (1-D) discontinuities, like edges and contours, that are anisotropic and characterized by geometrical regularity along different directions. In our previous work, we proposed a construction of critically sampled perfect reconstruction anisotropic transform with directional vanishing moments (DVM) imposed in the corresponding basis functions, called directionlets. Here, we show that the computational complexity of our transform is comparable to the complexity of the standard 2-D WT and substantially lower than the complexity of other similar approaches. We also present a zerotree-based image compression algorithm using directionlets that strongly outperforms the corresponding method based on the standard wavelets at low bit rates.

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  • Lossy Network Correlated Data Gathering with High Resolution Coding

    Cristescu, R.; Beferull-Lozano, B.

    (2006). Article

    Sensor networks measuring correlated data are considered, where the task is to gather data from the network nodes to a sink. A specific scenario is addressed, where data at nodes are lossy coded with high-resolution, and the information measured by the nodes has to be reconstructed at the sink within both certain total and individual distortion bounds. The first problem considered is to find the optimal transmission structure and the rate-distortion allocations at the various spatially located nodes, such as to minimize the total power consumption cost of the network, by assuming fixed nodes positions. The optimal transmission structure is the shortest path tree and the problems of rate and...

    Sensor networks measuring correlated data are considered, where the task is to gather data from the network nodes to a sink. A specific scenario is addressed, where data at nodes are lossy coded with high-resolution, and the information measured by the nodes has to be reconstructed at the sink within both certain total and individual distortion bounds. The first problem considered is to find the optimal transmission structure and the rate-distortion allocations at the various spatially located nodes, such as to minimize the total power consumption cost of the network, by assuming fixed nodes positions. The optimal transmission structure is the shortest path tree and the problems of rate and distortion allocation separate in the high-resolution case, namely, first the distortion allocation is found as a function of the transmission structure, and second, for a given distortion allocation, the rate allocation is computed. The second problem addressed is the case when the node positions can be chosen, by finding the optimal node placement for two different targets of interest, namely total power minimization and network lifetime maximization. Finally, a node placement solution that provides a tradeoff between the two metrics is proposed.

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