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Item Augmented Reality with Multilayer Occlusion(The Eurographics Association, 2006) Feng, Yan; Chen, Yimin; Louise M. Lever and Mary McDerbyAn 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.Item 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 McDerbyAutomatic 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.Item Polynomial Approximation of Blinn-Phong Model(The Eurographics Association, 2006) Öztürk, Aydin; Bilgili, Ahmet; Kurt, Murat; Louise M. Lever and Mary McDerbyThe 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.Item A Mixed Reality Anatomy Teaching Tool(The Eurographics Association, 2006) Thomas, Rhys G.; John, Nigel W.; Lim, Ik Soo; Louise M. Lever and Mary McDerbyIn 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.Item State of the Art Non-Photorealistic Rendering (NPR) Techniques(The Eurographics Association, 2006) Sayeed, Rezwan; Howard, Toby; Louise M. Lever and Mary McDerbyThe 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.Item GraSSML: Smart Schematic Diagrams, XML and Accessibility(The Eurographics Association, 2006) Fredj, Z. Ben; Duce, D. A.; Louise M. Lever and Mary McDerbyThis 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.Item Visualisation of DNA - Does the Soul Have a Picture?(The Eurographics Association, 2006) Middleton, M.; Yue, Y.; Louise M. Lever and Mary McDerbyAlthough there has been a great deal of research on DNA, DNA visualisation has been long overlooked. This paper studies current techniques for 2-dimensional and 3-dimensional DNA visualisation and other relevant areas such as music and fractals. The paper then presents a new approach to displaying DNA data. An algorithm is designed and implemented with OpenGL to manipulate and display unique DNA strings. Unique colourings are applied to each part of the string. The output is customised and offers the option to animate the DNA string over time. The results are examined and future areas of work recommendeItem Expressive and Dynamic Deformation of Animated Computer-Generated Characters(The Eurographics Association, 2006) Noble, Paul; Tang, Wen; Louise M. Lever and Mary McDerby3D computer animated characters often lack the communicative power and the expressiveness of traditional animation, especially when used in non-photorealistic graphical representations. Inspired by a talk by Pixar Animation Studios at Animex 2005 [WR05] and based upon the animation and cartooning concepts of lines of action and motion, we present an expressive animation tool that emphasizes and accentuates the intentions of the animator derived from the skeleton-driven animation. Motion and pose-based shape deformations are automatically generated to quickly add an emotive layer to an animated character. This warping of the character geometry also provides a novel solution to the problem of implied motion in non-photorealistic still images.Item Computing Static Electricity on Human Hair(The Eurographics Association, 2006) Sobottka, Gerrit; Weber, Andreas; Louise M. Lever and Mary McDerbyWe present a framework to study electrical charge phenomena on human hair. We propose a fiber based hair model which bases on the special theory of Cosserat Rods to overcome the well known difficulties one has to deal with when simple particle systems are used. We show how such models can efficiently be employed in conjunction with the fast multipole method to account for Coulomb far-field interactions. Furthermore, we extend our model such that we can account for environmental conditions.Item Perception-based Lighting Design(The Eurographics Association, 2006) Ha, Hai Nam; Olivier, Patrick; Louise M. Lever and Mary McDerbyPerception-based lighting design approaches model image quality using a cognitively grounded objective function which is in turn optimised through manipulation of the lighting parameters of a scene. We present, and demonstrate, a detailed implementation of perception-based lighting design, including the application and evaluation of stochastic optimisation using genetic algorithms.