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Now showing 1 - 10 of 27
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    Freehand 3D Curve Recognition and Oversketching
    (The Eurographics Association, 2005) Han, Li; Amicis, Raffaele De; Conti, Giuseppe; Louise M. Lever and Mary McDerby
    In the CAD/CAS field, the increasing domination of spline-based graphic objects has driven a great attention to methods focusing on the management of free-form curves. Based on the quick brainstorm illustration and stepwise refinement characteristics in conceptual designing stage, we present a method, which automatically reconstructs the designer s free-form 3D curve through recognizing his design intention . This algorithm automatically extracts the relevant control points through corner detection and dynamic-threshold sampling mechanism; as a result the Bspline curve is approximately produced. Furthermore, considering the ambiguity of designer s intention during the conceptual designing, this redraw operation feature is implemented through the so-called over-sketching . For this we introduce constrained length and tangent angle features, which supports fully free form 3D curve sketching, and it is capable of effectively smoothen transition interval. The method has been tested with various types of sketches, which are rendered in 3D scene environment. We further discuss the modification and its application to surfaces.
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    Implementing an Improved Stereoscopic Camera Model
    (The Eurographics Association, 2005) Froner, Barbara; Holliman, Nick; Louise M. Lever and Mary McDerby
    The usable perceived depth range of all stereoscopic 3D displays is limited by human factors considerations to a bounded range around the plane of the display. To account for this our Three Region stereoscopic camera model is able to control the depth mapping from scene to display while allowing a defined region of interest in scene depth to have an improved perceived depth representation compared to other regions of the scene. This can be categorized as a focus+context algorithm that manipulates stereoscopic depth representation along the viewing axis of the camera. We present a new implementation of the Three Region stereoscopic camera model as a Utility plug-in for the popular modelling and rendering package 3ds max. We describe our user interface, designed to incorporate stereoscopic image generation into the user s natural work flow. The implementation required us to overcome a number of technical challenges including; accurately measuring scene depth range, simulating asymmetric camera frustum in a system only supporting symmetric frustum, merging multiple renderings and managing anti-aliasing in layered images. We conclude from our implementation that it is possible to incorporate high quality stereoscopic camera models into standard graphics packages.
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    The Data Surface Interaction Paradigm
    (The Eurographics Association, 2005) Lindell, Rikard; Larsson, Thomas; Louise M. Lever and Mary McDerby
    This paper presents, in contrasts to the desktop metaphor, a content centric data surface interaction paradigm for graphical user interfaces applied to music creativity improvisation. Issues taken into account were navigation and retrieval of information, collaboration, and creative open-ended tasks. In this system there are no windows, icons, menus, files or applications. Content is presented on an infinitely large two-dimensional surface navigated by incremental search, zoom, and pan. Commands are typed aided by contextual help, visual feedback, and text completion. Components provide services related to different content modalities. Synchronisation of data surface content sustains mutual awareness of actions and mutual modifiability. The prototype music tool was evaluated with 10 users; it supported services expected by users, their creativity in action, and awareness in collaboration. User responses to the prototype tool were: It feels free, it feels good for creativity, and it s easy and fun to use.
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    Virtual Sculpting Using Implicit Surfaces with Scattered Data Interpolation
    (The Eurographics Association, 2005) Zhang, K.; Noble, R. A.; McDermott, R. J.; Wilson, A.; Louise M. Lever and Mary McDerby
    This paper presents a virtual sculpting system that shows an approach to the interactive deformation of soft objects. The soft objects are represented by implicit surfaces which are visualized using a constrained particle method. Those particles are arranged in an efficient cubical structure in which its processing speed is faster than some other surface sampling algorithms. The sculpted result can be stored in a compact form by interpolating the constrained particles using scattered data interpolation. The user can control the complexity of the sculpted shape by specifying the sampling density. In addition, the way in which the tool deforms the clay can be controlled explicitly by some control parameters. The surfaces are displayed with a stereoscopic viewer and the virtual tools are manipulated using a spaceball with 6 degrees of freedom.
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    Perceptually-Oriented Interest Management In Large-Scale Networked Virtual Environments
    (The Eurographics Association, 2005) Dunwell, I.; Whelan, J. C.; Louise M. Lever and Mary McDerby
    Amongst the most significant challenges in developing large-scale multi-user virtual environments is the efficient filtering of data to each user - a process commonly described as "interest management". This work-in-progress paper presents a broad summary of existing approaches, placing an emphasis upon the relationship between interest management and human perception. Subsequently, an introduction to the challenges in evaluating the success of interest management, given such a relationship to perception, is presented. The initial development of a test environment aimed at overcoming some of the challenges in providing a platform for such evaluation is then described, together with discussion of a perceptually-oriented approach to interest management which relies on the description of perception as a dynamic field, formed by analysis of the user's focus.
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    Real-time Simulation of Crowds Using Voronoi Diagrams
    (The Eurographics Association, 2005) Champagne, J.; Tang, W.; Louise M. Lever and Mary McDerby
    In this paper, we present a novel approach for real-time simulation of crowds. Our method is to compute generalised 2D Voronoi diagrams on environment maps for the locations of agents in the crowds. The Voronoi diagrams are generated efficiently with graphics hardware by calculating the closest Voronoi site and the distance to that site using polygon scan conversion and the z-buffer depth comparison. Because Voronoi diagrams have unique features of spatial tessellations which give optimised partitions of space for locating the agents especially groups of agents in a virtual environment, agents in the same group are placed within the Voronoi region which encloses the nearest locations to the geometric centre of the group. Each group of agents within its own Voronoi region follows the geometric centre of the region that is moving on the paths of the maps. During the simulation, agents in groups move closely together and avoid collusions with other groups on the way. With carefully designed rules for collision response the algorithm can generate natural-looking group behaviors of large crowds in real-time. Each agent within a group only detects collisions with other agents of the group and with static obstacles in the environment. Efficiency of the simulation is also gained through such multi-level behavioral simulation approach.
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    Ubiquitous Virtual Reality: Accessing Shared Virtual Environments through Videoconferencing Technology
    (The Eurographics Association, 2005) Pfeiffer, Thies; Weber, Matthias; Jung, Bernhard; Louise M. Lever and Mary McDerby
    This paper presents an alternative to existing methods for remotely accessing Virtual Reality (VR) systems. Common solutions are based on specialised software and/or hardware capable of rendering 3D content, which not only restricts accessibility to specific platforms but also increases the barrier for non expert users. Our approach addresses new audiences by making existing Virtual Environments (VEs) ubiquitously accessible. Its appeal is that a large variety of clients, like desktop PCs and handhelds, are ready to connect to VEs out of the box. We achieve this combining established videoconferencing protocol standards with a server based interaction handling. Currently interaction is based on natural speech, typed textual input and visual feedback, but extensions to support natural gestures are possible and planned. This paper presents the conceptual framework enabling videoconferencing with collaborative VEs as well as an example application for a virtual prototyping system.
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    Towards Realism in Facial Image Prototyping: Results of a Wavelet MRF Method
    (The Eurographics Association, 2005) Tiddeman, Bernard; Stirrat, Michael; Perrett, David; Louise M. Lever and Mary McDerby
    The ability to combine multiple images to produce a composite that is representative of the set has applications in psychology research, medical imaging and entertainment. Current techniques using a combination of image warping and blending suffer from a lack of realism due to unrealistic or inappropriate textures in the output images. This paper describes a new method for improving the representation of textures when blending multiple facial images. We select the most likely value for each pixel, given the values of the neighbouring pixels, by learning from the corresponding values in the training set i.e. we use a Markov Random Field (MRF) texture model. We use a multi-scale neighbourhood and separate low and high frequency information using a wavelet transform. This ensures proper correlations of values across spatial scales and allows us to bias the global appearance to the mean for the set, while selecting more specific texture components at higher resolutions. We validate our results using perceptual testing that shows that the new prototypes improve realism over previous techniques.
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    Integrating Abstract and Physical Molecular Model Interaction
    (The Eurographics Association, 2005) Thorne, Dave; Pettifer, Steve; Attwood, Terri; Louise M. Lever and Mary McDerby
    Historically, bioinformaticians have carried out protein analysis in one of two ways: by concentrating on either the physical structural representation of the subject data or a more abstract sequential representation. This paper describes a system currently in development at The University of Manchester that attempts to unify these two paradigms. We discuss the use of high-end rendering techniques to greatly increase the level of detail and interactivity of molecular visualisation, and describe the requirements placed upon that visualisation by the relationship between the abstract and physical models.
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    Real-Time Animation of Particles and Seaweeds in Underwater Scenes
    (The Eurographics Association, 2005) Coulais, Y.; Ghazanfarpour, D.; Terraz, O.; Thon, S.; Louise M. Lever and Mary McDerby
    Water is one of the most important natural phenomena to be rendered in computer graphics. Although ocean waves animation has been well studied in Computer graphics, only few studies have been done for underwater animation. In this paper, we present a new real-time method for animation of suspended particles and seaweeds in underwater scenes. One of the main advantages of this method, compared to other approaches, is the real-time animation of submerged objects by taking into account some natural underwater forces that govern their movements, such as forces generated by water surface in deep and shallow waters as well as underwater currents. Taking into account forces generated by ocean surface is an original approach in Computer Graphics. In addition, real-time animation of complex underwater scenes composed of a great number of particles and seaweeds can be performed by the use of appropriate levels of details.