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  • Cage-free spatial deformations

     Cervero Abello, Maria Angels; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications
    Presentation's date: 2013-02
    Presentation of work at congresses

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    We propose a new deformation scheme for polygonal meshes through generalized barycentric coordinates that does not require any explicit cage definition. Our system infers the connectivity of the control points defined by the user and computes the coordinates using this structure. This allows the user to incrementally position the control points (or delete them) wherever he considers more suitable. This freedom gives more control, precision and locality to the deformation process.

  • Enhanced Perception in Volume Visualization  Open access

     Díaz Iriberri, José
    Defense's date: 2013-04-26
    Universitat Politècnica de Catalunya
    Theses

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    Due to the nature of scientic data sets, the generation of convenient visualizations may be a difficult task, but crucial to correctly convey the relevant information of the data. When working with complex volume models, such as the anatomical ones, it is important to provide accurate representations, since a misinterpretation can lead to serious mistakes while diagnosing a disease or planning surgery. In these cases, enhancing the perception of the features of interest usually helps to properly understand the data. Throughout years, researchers have focused on different methods to improve the visualization of volume data sets. For instance, the definition of good transfer functions is a key issue in Volume Visualization, since transfer functions determine how materials are classified. Other approaches are based on simulating realistic illumination models to enhance the spatial perception, or using illustrative effects to provide the level of abstraction needed to correctly interpret the data. This thesis contributes with new approaches to enhance the visual and spatial perception in Volume Visualization. Thanks to the new computing capabilities of modern graphics hardware, the proposed algorithms are capable of modifying the illumination model and simulating illustrative motifs in real time. In order to enhance local details, which are useful to better perceive the shape and the surfaces of the volume, our first contribution is an algorithm that employs a common sharpening operator to modify the lighting applied. As a result, the overall contrast of the visualization is enhanced by brightening the salient features and darkening the deeper regions of the volume model. The enhancement of depth perception in Direct Volume Rendering is also covered in the thesis. To do this, we propose two algorithms to simulate ambient occlusion: a screen-space technique based on using depth information to estimate the amount of light occluded, and a view-independent method that uses the density values of the data set to estimate the occlusion. Additionally, depth perception is also enhanced by adding halos around the structures of interest. Maximum Intensity Projection images provide a good understanding of the high intensity features of the data, but lack any contextual information. In order to enhance the depth perception in such a case, we present a novel technique based on changing how intensity is accumulated. Furthermore, the perception of the spatial arrangement of the displayed structures is also enhanced by adding certain colour cues. The last contribution is a new manipulation tool designed for adding contextual information when cutting the volume. Based on traditional illustrative effects, this method allows the user to directly extrude structures from the cross-section of the cut. As a result, the clipped structures are displayed at different heights, preserving the information needed to correctly perceive them.

    Debido a la naturaleza de los datos científicos, visualizarlos correctamente puede ser una tarea complicada, pero crucial para interpretarlos de forma adecuada. Cuando se trabaja con modelos de volumen complejos, como es el caso de los modelos anatómicos, es importante generar imágenes precisas, ya que una mala interpretación de las mismas puede producir errores graves en el diagnóstico de enfermedades o en la planificación de operaciones quirúrgicas. En estos casos, mejorar la percepción de las zonas de interés, facilita la comprensión de la información inherente a los datos. Durante décadas, los investigadores se han centrado en el desarrollo de técnicas para mejorar la visualización de datos volumétricos. Por ejemplo, los métodos que permiten definir buenas funciones de transferencia son clave, ya que éstas determinan cómo se clasifican los materiales. Otros ejemplos son las técnicas que simulan modelos de iluminación realista, que permiten percibir mejor la distribución espacial de los elementos del volumen, o bien los que imitan efectos ilustrativos, que proporcionan el nivel de abstracción necesario para interpretar correctamente los datos. El trabajo presentado en esta tesis se centra en mejorar la percepción de los elementos del volumen, ya sea modificando el modelo de iluminación aplicado en la visualización, o simulando efectos ilustrativos. Aprovechando la capacidad de cálculo de los nuevos procesadores gráficos, se describen un conjunto de algoritmos que permiten obtener los resultados en tiempo real. Para mejorar la percepción de detalles locales, proponemos modificar el modelo de iluminación utilizando una conocida herramienta de procesado de imágenes (unsharp masking). Iluminando aquellos detalles que sobresalen de las superficies y oscureciendo las zonas profundas, se mejora el contraste local de la imagen, con lo que se consigue realzar los detalles de superficie. También se presentan diferentes técnicas para mejorar la percepción de la profundidad en Direct Volume Rendering. Concretamente, se propone modificar la iluminación teniendo en cuenta la oclusión ambiente de dos maneras diferentes: la primera utiliza los valores de profundidad en espacio imagen para calcular el factor de oclusión del entorno de cada pixel, mientras que la segunda utiliza los valores de densidad del volumen para aproximar dicha oclusión en cada vóxel. Además de estas dos técnicas, también se propone mejorar la percepción espacial y de la profundidad de ciertas estructuras mediante la generación de halos. La técnica conocida como Maximum Intensity Projection (MIP) permite visualizar los elementos de mayor intensidad del volumen, pero no aporta ningún tipo de información contextual. Para mejorar la percepción de la profundidad, proponemos una nueva técnica basada en cambiar la forma en la que se acumula la intensidad en MIP. También se describe un esquema de color para mejorar la percepción espacial de los elementos visualizados. La última contribución de la tesis es una herramienta de manipulación directa de los datos, que permite preservar la información contextual cuando se realizan cortes en el modelo de volumen. Basada en técnicas ilustrativas tradicionales, esta técnica permite al usuario estirar las estructuras visibles en las secciones de los cortes. Como resultado, las estructuras de interés se visualizan a diferentes alturas sobre la sección, lo que permite al observador percibirlas correctamente.

  • SAMBA: steadied choreographies

     Rossignac, Jarek; Luffel, Mark; Vinacua Pla, Alvaro
    Annual Symposium on Computational Aesthetics in Graphics, Visualization, and Imaging
    Presentation's date: 2012-06-04
    Presentation of work at congresses

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  • Example-guided segmentation

     Chica Calaf, Antonio; Monclús Lahoya, Eva; Brunet Crosa, Pere; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Graphical models
    Date of publication: 2012-11
    Journal article

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  • Avances en realidad virtual para aplicaciones punteras

     Lligadas Rodriguez, Xavier; Susin Sanchez, Antonio; Brunet Crosa, Pere; Vinacua Pla, Alvaro; Fairen Gonzalez, Marta; Andujar Gran, Carlos A.; Monclús Lahoya, Eva; Vazquez Alcocer, Pere Pau; Campoalegre Vera, Lazaro; Argelaguet Sanz, Fernando; Pelechano Gomez, Nuria; Díaz Iriberri, José; Chica Calaf, Antonio; Cervero Abello, Maria Angels; Ojeda Contreras, Jesus; Beacco Porres, Alejandro; Navazo Alvaro, Isabel
    Participation in a competitive project

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  • Mesh repair with user-friendly topology control

     Hétroy, Franck; Rey, Stéphanie; Andujar Gran, Carlos A.; Brunet Crosa, Pere; Vinacua Pla, Alvaro
    Computer Aided Design
    Date of publication: 2011-01
    Journal article

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    Limitations of current 3D acquisition technology often lead to polygonal meshes exhibiting a number of geometrical and topological defects which prevent them from widespread use. In this paper we present a new method for model repair which takes as input an arbitrary polygonal mesh and outputs a valid 2-manifold triangle mesh. Unlike previous work, our method allows users to quickly identify areas with potential topological errors and to choose how to fix them in a user-friendly manner. Key steps of our algorithm include the conversion of the input model into a set of voxels, the use of morphological operators to allow the user to modify the topology of the discrete model, and the conversion of the corrected voxel set back into a 2-manifold triangle mesh. Our experiments demonstrate that the proposed algorithm is suitable for repairing meshes of a large class of shapes.

  • Steady affine motions and morphs

     Rossignac, Jarek; Vinacua Pla, Alvaro
    ACM transactions on graphics
    Date of publication: 2011-10
    Journal article

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    Volume-preserving deformation using generalized barycentric coordinates  Open access

     Cervero Abello, Maria Angels; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    Congreso Español de Informática Gráfica
    Presentation's date: 2010-09
    Presentation of work at congresses

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    The cage-based deformation of a 3D object through generalized barycentric coordinates is a simple, e fficient, effective and hence widely used shape manipulation scheme. Editing vertices of the polyhedral cage induces a smooth space deformation of its interior; the vertices thus become control handles of the final deformation. However, in some application fi elds, as medicine, constrained volume preserving deformations are required. In this paper, we present a solution that takes advantage of the potential of the deformations based on generalized barycentric coordinates while adding the constraint of keeping a volume constant. An implementation of the proposed scheme is presented and discussed. A measure of local stress of the deformed volume is also proposed.

    Postprint (author’s final draft)

  • GRUP DE RECERCA EN VISUALITZACIO, REALITAT VIRTUAL I INTERACCIO GRAFICA (VIRVIG)

     Vinacua Pla, Alvaro; Chica Calaf, Antonio; Díaz Iriberri, José; Vazquez Alcocer, Pere Pau; Susin Sanchez, Antonio; Monclús Lahoya, Eva; Andujar Gran, Carlos A.; Fairen Gonzalez, Marta; Cervero Abello, Maria Angels; Ojeda Contreras, Jesus; Lligadas Rodriguez, Xavier; Argelaguet Sanz, Fernando; Pelechano Gomez, Nuria; Campoalegre Vera, Lazaro; Navazo Alvaro, Isabel; Brunet Crosa, Pere
    Participation in a competitive project

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  • Massive mesh hole repair minimizing user intervention

     Brunet Crosa, Pere; Chica Calaf, Antonio; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Computing
    Date of publication: 2009-10
    Journal article

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    Piecewise algebraic surface computation and smoothing from a discrete model  Open access

     Esteve Cusine, Jordi; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    Computer aided geometric design
    Date of publication: 2008-08
    Journal article

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    This paper describes a contrained fairing method for implicit surfaces defined on a voxelization. This method is suitable for computing a closed smooth surface that approximates an initial set of face connected

  • Pressing: Smooth Isosurfaces with Flats from Binary Grids

     Chica Calaf, Antonio; Williams, J; Andujar Gran, Carlos A.; Brunet Crosa, Pere; Navazo Alvaro, Isabel; Rossignac, J; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2008-01
    Journal article

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  • Omni-directional relief impostors

     Andujar Gran, Carlos A.; Boo, J; Brunet Crosa, Pere; Fairen Gonzalez, Marta; Navazo Alvaro, Isabel; Vazquez Alcocer, Pere Pau; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2007-07
    Journal article

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  • Registro 3D y 4D de imágenes cardíacas SPECT

     Murillo, Santiago; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Congreso Español de Informática Gráfica
    Presentation's date: 2007-09
    Presentation of work at congresses

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    Los estudios de cardiología nuclear provenientes de captaciones cardíacas 4D gated SPECT (Single Photon Emission Computed Tomographic) aportan información sobre la perfusión del ventrículo izquierdo en diferentes fases del ciclo cardíaco. Para el pronóstico de la viabilidad del miocardio es importante comparar la perfusión del miocardio con el paciente en estado de reposo y en esfuerzo. En este artículo presentamos un método de registro para imágenes cardíacas SPECT, basado en la Información Mutua (IM) como medida de similitud, que utiliza toda la información contenida en la captación. Ésta puede representar un instante del ciclo cardíaco (registro 3D) o una serie temporal de captaciones (registro 4D). La propuesta se basa en un nuevo método de interpolación que es especialmente significativo en el registro de imágenes de baja resolución. La utilización de toda la información disponible en la captación junto con el nuevo método de interpolación, conducen a un método de registro efciente y de alta precisión.

  • Buque Autónomo Polivalente para la Pesca 2020 (BAIP 2020)

     González Blanco, Ricardo; Garcia Espinosa, Julio; Mari Sagarra, Ricardo; Brunet Crosa, Pere; Vinacua Pla, Alvaro; Navazo Alvaro, Isabel
    Participation in a competitive project

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  • Data-driven tetrahedral mesh subdivision

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2007-12
    Journal article

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    Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm’s performance and applications.

  • User-Guided Inverse Reflector Design

     Patow, G; Pueyo, X; Vinacua Pla, Alvaro
    Computers & graphics
    Date of publication: 2007-06
    Journal article

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  • Modelling Very Complex Assemblies: The Use of Discrete and Hierarchical Models

     Brunet Crosa, Pere; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Computer-aided design and applications
    Date of publication: 2006-06
    Journal article

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  • Data-driven tetrahedral mesh subdivision

     Rodriguez, Lyudmila; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Ibero-American Symposium on Computer Graphics
    Presentation's date: 2006-07
    Presentation of work at congresses

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    Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm’s performance and applications.

  • IST-027731 PRESENCCIA coordinació

     Slater, Melvyn; Navazo Alvaro, Isabel; Brunet Crosa, Pere; Vinacua Pla, Alvaro; Andujar Gran, Carlos A.
    Participation in a competitive project

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  • Pressing: Smooth Isosurfaces with Flats from Binary Grids

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Date: 2006-02
    Report

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    A topological comparison of surface extraction algorithms  Open access

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Fairen Gonzalez, Marta; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Date: 2006-01
    Report

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    In many application areas, it is useful to convert the discrete information stored in the nodes of a regular grid into a continuous boundary model. Isosurface extraction algorithms di er on how the discrete information in the grid is generated, on what information does the grid store and on the properties of the output surface.

  • Data-driven Tetrahedral Mesh Subdivision

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Date: 2006-09
    Report

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  • Data-driven Tetrahedral Mesh Subdivision

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Date: 2006-09
    Report

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    Volume cardiac SPECT image registration  Open access

     Murillo, Santiago; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    International Conference on Medical Information Visualization
    Presentation's date: 2006
    Presentation of work at congresses

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    The registration of cardiac images is relevant for the diagnosis of cardiac pathologies. In the case of SPECT (Single Photon Emission Computer Tomography) datasets, this is difficult because of the low resolution of the images. In this paper we present a new registration method for 3D images with poor resolution. Our method is based on the maximization of the mutual information (MI) using a new interpolation method which significantly improves the result of an MI-based strategy on low resolution images. We also use a different optimization strategy than other MI-based algorithms, typically achieving errors of the order of one pixel. We also discuss experimental results of our method.

  • Approximation of a variable density cloud of points by shrinking a discrete membrane

     Esteve Cusine, Jordi; Brunet Crosa, Pere; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2005-12
    Journal article

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    This paper describes a method to obtain a closed surface that approximates a general 3D data point set with nonuniform density. Aside from the positions of the initial data points, no other information is used. Particularly, neither the topological relations between the points nor the normal to the surface at the data points are needed. The reconstructed surface does not exactly interpolate the initial data points, but approximates them with a bounded maximum distance. The method allows one to reconstruct closed surfaces with arbitrary genus and closed surfaces with disconnected shells

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    Optimizing the topological and combinatorial complexity of isosurfaces  Open access

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Chica Calaf, Antonio; Navazo Alvaro, Isabel; Rossignac, Jarek; Vinacua Pla, Alvaro
    Computer Aided Design
    Date of publication: 2005-07
    Journal article

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    Since the publication of the original Marching Cubes algorithm, numerous variations have been proposed for guaranteeing water-tight constructions of triangulated approximations of isosurfaces. Most approaches divide the 3D space into cubes that each occupy the space between eight neighboring samples of a regular lattice. The portion of the isosurface inside a cube may be computed independently of what happens in the other cubes, provided that the constructions for each pair of neighboring cubes agree along their common face. The portion of the isosurface associated with a cube may consist of one or more connected components, which we call sheets. The topology and combinatorial complexity of the isosurface is influenced by three types of decisions made during its construction: (1) how to connect the four intersection points on each ambiguous face, (2) how to form interpolating sheets for cubes with more than one loop, and (3) how to triangulate each sheet. To determine topological properties, it is only relevant whether the samples are inside or outside the object, and not their precise value, if there is one. Previously reported techniques make these decisions based on local —per cube— criteria, often using precomputed look-up tables or simple construction rules. Instead, we propose global strategies for optimizing several topological and combinatorial measures of the isosurfaces: triangle count, genus, and number of shells. We describe efficient implementations of these optimizations and the auxiliary data structures developed to support them.

  • REFLECTOR SHAPE DESIGN FROM RADIANCE DISTRIBUTIONS. CAD FOR LUMINARIES

     ARIEL PATOW, GUSTAVO
    Defense's date: 2005-10-28
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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    Piecewise algebraic surface computation and fairing from a discrete model  Open access

     Esteve Cusine, Jordi; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    Date: 2005-10
    Report

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    This paper describes a constrained fairing method for implicit surfaces defined on a voxelization. This method is suitable for computing a closed smooth surface that approximates an initial set of face connected voxels.

  • Computing maximal tiles and application to impostor-based simplification

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Chica Calaf, Antonio; Navazo Alvaro, Isabel; Rossignac, J; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2004-08
    Journal article

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    The computation of the largest planar region approximating a 3D object is an important problem with wide applications in modeling and rendering. Given a voxelization of the 3D object, we propose an efficient algorithm to solve a discrete version of this problem. The input of the algorithm is the set of grid edges connecting the interior and the exterior of the object (called sticks). Using a voting-based approach, we compute the plane that slices the largest number of sticks and is orientation-compatible with these sticks. The robustness and efficiency of our approach rests on the use of two different parameterizations of the planes with suitable properties. The first of these is exact and is used to retrieve precomputed local solutions of the problem. The second one is discrete and is used in a hierarchical voting scheme to compute the global maximum. This problem has diverse applications that range from finding object signatures to generating simplified models. Here we demonstrate the merits of the algorithm for efficiently computing an optimized set of textured impostors for a given polygonal model.

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    Optimal iso-surfaces  Open access

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Chica Calaf, Antonio; Navazo Alvaro, Isabel; Rossignac, Jarek; Vinacua Pla, Alvaro
    Computer-aided design and applications
    Date of publication: 2004-05
    Journal article

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    Since the publication of the original Marching Cubes algorithm, numerous variations have been proposed for guaranteeing water-tight constructions of triangulated approximations of iso-surfaces. Most approaches divide the 3D space into cubes that each occupies the space between eight neighboring samples of a regular lattice. The portion of the iso-surface inside a cube may be computed independently of what happens in the other cubes, provided that the constructions for each pair of neighboring cubes agree along their common face. The portion of the iso-surface associated with a cube may consist of one or more connected components, which we call sheets. We distinguish three types of decisions in the construction of the iso-surface connectivity: (1) how to split the X-faces, which have alternating in/out samples, (2) how many sheets to use in a cube, and (3) how to triangulate each sheet. Previously reported techniques make these decisions based on local criteria, often using pre-computed look-up tables or simple construction rules. Instead, we propose global strategies for optimizing several topological and combinatorial measures of the isosurfaces: triangle count, genus, and number of shells. We describe efficient implementations of these optimizations and the auxiliary data structures developed to support them.

  • An Application for Dealing with Missing Data in Medical Images, with Application to Left Ventricle SPECT Data

     Navazo Alvaro, Isabel; Vinacua Pla, Alvaro; Civit, O; Viancua, A
    Date of publication: 2004-01-31
    Book chapter

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  • Tetrahedral mesh subdivision based on underlying volume data

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Date: 2004-05
    Report

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  • Reflector design from radiance distributions

     Patow, Gustavo Ariel; Pueyo, Xavier; Vinacua Pla, Alvaro
    International journal of shape modeling (paper)
    Date of publication: 2004-12
    Journal article

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    This paper proposes a technique for the design of reflector shapes from prescribed optical properties (far field radiance distribution) and geometrical constraints, which is of high importance in the field of Lighting Engineering, more specifically for Luminaire Design. The reflector shape to be found is just a part of a set of pieces of what is known in lighting engineering as an optical set, and is composed of a lamp (light source), a reflector, a holding case and a glass that protects the system from dust and other environmental phenomena. Thus, we aim at the design and development of a system capable of generating a reflector shape in a way such that the optical set emits a given, user defined, far field radiance distribution. This problem can be put in the mathematical context of inverse problems, which refer to all the problems where, contrary to what happens with traditional direct problems, several aspects of the scene are unknown. Then, the algorithm is allowed to work backwards to establish the missing parameters. In order to do so, light propagation inside and outside the optical set must be computed and the resulting radiance distribution compared to the desired one. Finally, constraints on the shape imposed by industry needs must be taken into account, bounding the set of possible shape definitions. The general approach taken is based on a minimization procedure on the space of possible reflector shapes. The algorithm moves towards minimizing the distance, in the I2 metric, between the resulting illumination far from the reflector and a prescribed, ideal optical radiance distribution specified at the far field by the user.

  • Robust Face Recovery for Hybrid Surface Visualization

     Andujar Gran, Carlos A.; Brunet Crosa, Pere; Esteve Cusine, Jordi; Monclús Lahoya, Eva; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Vision Modeling and Visualization 2003
    Presentation of work at congresses

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  • Modelo volumetrico del ventriculo izquierdo

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    XIII Congreso Español de Informática Gràfica
    Presentation of work at congresses

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  • A tetrahedral model to represent the left ventricle volume of the heart

     Rodriguez Pérez, Lyudmila Odalina; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro
    Vision Modeling and Visualization 2002
    Presentation of work at congresses

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  • Transparency on developing distributed applications with ATLAS

     Fairen Gonzalez, Marta; Vinacua Pla, Alvaro
    IASTED International Conference on Parallel and Distributed Computing and Systems
    Presentation of work at congresses

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  • Computer graphics forum

     Vinacua Pla, Alvaro
    Collaboration in journals

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  • Approximation of a variable density cloud of points by shrinking a discrete membrane

     Esteve Cusine, Jordi; Brunet Crosa, Pere; Vinacua Pla, Alvaro
    Date: 2002-12
    Report

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  • Partial and total recovery in ATLAS

     Fairen Gonzalez, Marta; Vinacua Pla, Alvaro
    IASTED International Conference on Applied Informatics
    Presentation of work at congresses

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  • Multiresolution for algebraic curves and surfaces using wavelets

     Esteve Cusine, Jordi; Brunet Crosa, Pere; Vinacua Pla, Alvaro
    Computer graphics forum
    Date of publication: 2001-01
    Journal article

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    This paper describes a multiresolution method for implicit curves and surfaces. The method is based on wavelets, and is able to simplify the topology. The implicit curves and surfaces are defined as the zero-valued piece-wise algebraic isosurface of a tenser-product uniform cubic B-spline. A wavelet multiresolution method that deals with uniform cubic B-splines on bounded domains is proposed. In order to handle arbitrary domains the proposed algorithm dynamically adds appropriate control points and deletes them in the synthesis phase.

  • On the design and implementation of flexible software platforms to facilitate the development of advanced graphics applications  Open access

     Fairen Gonzalez, Marta
    Defense's date: 2000-11-23
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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    This thesis presents the design and implementation of a software development platform (ATLAS) which offers some tools and methods to greatly simplify the construction of fairly sophisticated applications. It allows thus programmers to include advanced features in their applications with no or very little extra information and effort. These features include: the splitting of the application in distinct processes that may be distributed over a network; a powerful configuration and scripting language; several tools including an input system to easily construct reasonable interfaces; a flexible journaling mechanism --offering fault-tolerance to crashes of processes or communications--; and other features designed for graphics applications, like a global data identification- --addressing the problem of volatile references and giving support to processes of constraint solving--, and a uniform but flexible view of inputs allowing many different dialogue modes.These can be seen as related or overlapping with CORBA or other systems like Horus or Arjuna, but none of them addresses simultaneously all aspects included in ATLAS; more specifically none of them offers a standardized input model, a configuration and macro language, a journaling mechanism or gives support to processes of constraints solving and parametric design.The contributions of ATLAS are in showing how all these requirements can be addressed together; also in showing means by which this can be attained with little or no performance cost and without imposing on developers the need of mastering all these techniques. Finally, the design of the ATLAS journaling system is to our knowledge original in the simultaneous solution of all of its requirements.

  • Dynamic Recognition and Reconstruction of the Human Heart

     Susin Sanchez, Antonio; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    International Conference on Pattern Recognition
    Presentation of work at congresses

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  • Utilización de la realidad virtual y modelos deformables para la simulación y diagnóstico de patologías cardíacas

     Vinacua Pla, Alvaro; Brunet Crosa, Pere; Susin Sanchez, Antonio
    Participation in a competitive project

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  • Dynamical recognition and reconstruction on the human heart.

     Susin Sanchez, Antonio; Navazo Alvaro, Isabel; Vinacua Pla, Alvaro; Brunet Crosa, Pere
    Date: 2000-04
    Report

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  • Polylines, tubes and inflections. Some definitions, results and algorithms

     Vivo Lorenzo, Manuel; Vinacua Pla, Alvaro
    Date: 2000-03
    Report

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  • Sistema avanzado de CAD Distribuido: Integracion final del software

     Brunet Crosa, Pere; Solano Albajes, Luis; Monclus, Eva; Fairen Gonzalez, Marta; Pueyo Sanchez, Xavier; Vivo Lorenzo, Manuel; Vinacua Pla, Alvaro; Navazo Alvaro, Isabel; Joan Arinyo, Robert; Vazquez Alcocer, Pere Pau
    Date: 1999-01
    Report

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  • Heterogeneous distribution in ATLAS

     Fairen Gonzalez, Marta; Vinacua Pla, Alvaro
    Date: 1999-12
    Report

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  • Automatic code generation for ATLAS communications drivers

     Vivo Lorenzo, Manuel; Fairen Gonzalez, Marta; Vinacua Pla, Alvaro
    Date: 1999-12
    Report

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