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Now showing 1 - 10 of 84
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    The Dynamic Animation of Ambulatory Arthropods
    (The Eurographics Association, 2007) Cenydd, Llyr ap; Teahan, William; Ik Soo Lim and David Duce
    Whilst advances in real-time computer graphics continue to permit the development of increasingly vivid virtual worlds, the degree of interaction between the environment and the animated characters within remains relatively limited. There has been little research into the realistic real-time simulation of creatures with the ability to scale arbitrary surfaces and fully explore their environment. Natural looking animations of such feats would greatly enhance immersion in computer games, as well as being of benefit to fields such as phobia therapy and Artificial Life research. We present a system for dynamically animating ground based arthropods in real-time, capable of traversing realistically across a complex, arbitrary environment. The physical simulation of the virtual world further grounds the creatures, enabling complex emergent animations to form.
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    Augmented Reality with Multilayer Occlusion
    (The Eurographics Association, 2006) Feng, Yan; Chen, Yimin; Louise M. Lever and Mary McDerby
    An algorithm for realizing multilayer occlusion in augmented reality (AR) is presented in this paper. We have designed a special scene graph tree comprised of some special nodes, namely EMO nodes. According to the location of real moving object, different EMO node will be activated in real-time, consequently realizing the multilayer occlusion. Differing qualitatively from previous work in AR occlusion, our algorithm realizes multilayer occlusion, and its application domain involves indoor-field occluded objects, which are several meters distant from the viewer. Previous related work has focused on monolayer occlusion, and near-field occluded objects, which are within or just beyond arm s reach. In addition, BP neural network is improved to correct the nonlinear error of magnetic sensor, consequently to detect occlusion more effectively. Experimental results are provided to demonstrate the multilayer indoor-field occlusion.
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    ATIP: A Tool for 3D Navigation inside a Single Image with Automatic Camera Calibration
    (The Eurographics Association, 2006) Boulanger, Kevin; Bouatouch, Kadi; Pattanaik, Sumanta; Louise M. Lever and Mary McDerby
    Automatic Tour Into the Picture (ATIP) is an extension of the Tour Into the Picture method [HAA97] that allows an approximative but visually convincing 3D walk-through inside a single image by rendering a box textured using the input image data. The original algorithm requires a long and tedious user interaction to determine the box dimensions and the perspective parameters, and imposes several constraints on the input image orientation. The goal of this paper is to present a framework providing fully automatic and fast camera calibration for any view orientation without using a calibration target. Our method reduces the user interaction, hence only a couple of seconds are required between the input image loading and the final walk-through.
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    Polynomial Approximation of Blinn-Phong Model
    (The Eurographics Association, 2006) Öztürk, Aydin; Bilgili, Ahmet; Kurt, Murat; Louise M. Lever and Mary McDerby
    The Phong model has been one of the oldest and the most popular reflection models in Computer Graphics. It can be used to model specular highlights of various materials. In this paper, we consider a polynomial model and obtain a linear approximation of the Blinn-Phong model. Approximation errors were obtained for the proposed model and empirical comparisons were made using a measured BRDF data set. Based on the empirical results, it is shown that proposed model provides visually convincing representation of BRDF and performs well for modeling the surface reflectance.
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    A Mixed Reality Anatomy Teaching Tool
    (The Eurographics Association, 2006) Thomas, Rhys G.; John, Nigel W.; Lim, Ik Soo; Louise M. Lever and Mary McDerby
    In this paper we present an inexpensive Mixed Reality software tool for training medical students in anatomy. The software integrates the ARToolkit and Visualization Toolkit (VTK) to create a novel interactive environment in which the user can manipulate the position and orientation of the volume rendering using a plastic model of the organ to be observed. The volume rendering can then be clipped relative to an arbitrary plane to reveal data from its interior, using a second prop.
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    State of the Art Non-Photorealistic Rendering (NPR) Techniques
    (The Eurographics Association, 2006) Sayeed, Rezwan; Howard, Toby; Louise M. Lever and Mary McDerby
    The emergence of non-photorealistic rendering (NPR) over the greater part of a decade has created an intriguing new field espousing expression, abstraction and stylisation in preference to the traditional computer graphics concerns for photorealism. By lifting the burden of realism, NPR is capable of engaging with users, providing compelling and unique experiences through devices such as abstraction and stylisation. Many artistic and visual styles have been achieved by NPR including interactive and automated systems for drawing and painting. In this paper we outline the current state-of-the-art of NPR for visualisation and identify some current and future trends in NPR research.
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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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    GPU-Based Wind Animation of Trees
    (The Eurographics Association, 2007) Skjermo, Jo; Ik Soo Lim and David Duce
    This paper present a simplified approach to wind animation of natural looking tree stems and branches. The presented approach is composed from several earlier works by a number of authors, each adapted to increase its suitability for processing on a Graphic Processing Unit (GPU). The outlined approach uses two passes through the GPU. The first pass samples from a simple wind force simulator based on sine sums. It then animates the parameters and the control points defining each branch using the sampled force, taking advantage of the parallel nature of GPU s. The second pass uses a previously presented GPU-based deformer to generate and render actual models of each branch, using the animated control points.
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    GraSSML: Smart Schematic Diagrams, XML and Accessibility
    (The Eurographics Association, 2006) Fredj, Z. Ben; Duce, D. A.; Louise M. Lever and Mary McDerby
    This paper describes work in progress at Oxford Brookes University. The project called Graphical Structure Semantic Markup Languages (GraSSML) aims at defining higher-level diagram description languages for the World Wide Web, which capture the structure and the semantics of a diagram and enable the generation of accessible and "smart" presentations in different modalities such as speech, text, and graphics. GraSSML is broken down into three levels: semantics, structure and presentation. Each of these levels captures a specific aspect of a diagram. The semantic level language is highly dependent on the type of diagram considered and the knowledge of the domain (ontology) in which it is used. Using the proposed approach, the structure and the semantics of the diagram is made available at the creation stage. The availability of this information offers new possibilities allowing Web Graphics to become "smart". The paper outlines the relevant limitations of SVG and some approaches aiming to resolve the problem of graphic accessibility. It then describes our approach in addressing some of these limitations and presents the new possibilities that these smart graphics lead to.