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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 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.Item Perceived Rendering Thresholds for High-Fidelity Graphics on Small Screen Devices(The Eurographics Association, 2006) Aranha, M.; Debattista, K.; Chalmers, A.; Hill, S.; Louise M. Lever and Mary McDerbySmall screen devices, also known as small-form-factor (SFF) devices including mobile phones and ultra mobile PCs are increasingly ubiquitous. Their uses includes gaming, navigation and interactive visualisation. SFF devices are, however, inherently limited by their physical characteristics for perception as well as limited processing and battery power. High-fidelity graphic systems have significant computational requirements which can be reduced through use of perceptually-based rendering techniques. In order to exploit these techniques on SFF devices a sound understanding of the perceptual characteristics of the display device is needed. This paper investigates the perceived rendering threshold specific for SFF devices in comparison to traditional display devices. We show that the threshold for SFF systems differs significantly from typical displays indicating substantial savings in rendering quality and thus computational resources can be achieved for SFF devices.Item Physically Based Simulation and Visualization of Fire in Real-Time using the GPU(The Eurographics Association, 2006) Rødal, Samuel; Storli, Geir; Gundersen, Odd Erik; Louise M. Lever and Mary McDerbyIn this paper we present a physically based framework for real-time simulation and visualization of fire using the GPU. The physics of fire is modeled through a combination of a fluid solver and a combustion process causing the characteristic motion of fire. The simulation results are then rendered using a particle system combined with a black-body radiation model where the physically based simulation governs both the motion and appearance of the particles. By performing individual slice simulations in 2D and combining them using volumetric extrusion we achieve better performance than by performing the simulation in 3D without compromising the visual quality. Thus, achieving our goal of visualizing bonfire and torch-like fire effects with high visual quality in real-time.Item Designing a Virtual Reality Game for the CAVE(The Eurographics Association, 2006) Livatino, S.; Agerbech, V.; Johansen, A.; Johansen, B.; S. Battiato and G. Gallo and F. StancoVirtual Reality has for many years been a technology which has stagnated in application and software development for games. The applications available for VR environments have increased but they mostly remain related to scientific purposes while computer games in VR are still being developed and only show a part of their actual potential. The game industry has begun to see the possibilities of VR games in a near future with the implementation of some popular games to a CAVE system. However, a full immersion VR solution still remains uncommon and expensive. This paper aims to demonstrate the potential of VR games, and in particular games for the CAVE, now that affordable solutions are close to reach as more powerful hardware is available at low price. The focus is also on the methodology to be pursued while designing a VR game. Results were encouraging and tests performed on a first prototype demonstrates system feasibility.Item Fast Rendering of Complex Dynamic Scenes(The Eurographics Association, 2006) KovalcÃk, Vit; Sochor, Jiri; Louise M. Lever and Mary McDerbyWe present a novel algorithm capable of rendering complex dynamic scenes at high frame rates. The key part of the algorithm is occlusion culling which is performed by an optimized usage of the hardware occlusion queries. The spatial organization of the scene using 2-level BSP-like hierarchy helps to speed up evaluating full and partial occlusion of the objects. The algorithm handles both static and dynamic objects and places no restrictions on the shape of objects.Item Structured Image Techniques for Efficient High-Fidelity Graphics(The Eurographics Association, 2006) Yang, X.; Debattista, K.; Chalmers, A.; Louise M. Lever and Mary McDerbyGlobal illumination rendering in real-time for high-fidelity graphics remains one of the biggest challenges for computer graphics in the foreseeable future. Recent work has shown that significant amounts of time can be saved by selectively rendering in high quality only those parts of the image that are considered perceptually more important. Regions of the final rendering that are deemed more perceptually important can be identified through lower quality, but rapid, rasterisation rendering. By exploiting this prior knowledge of the scene and taking advantage of image space based algorithms to concentrate rendering on the more salient areas higher performance rendering may be achieved. In this paper, we present a selective rendering framework based on ray tracing for global illumination which uses a rapid image preview of the scene to identify important image regions, structures these regions and uses this knowledge to direct a fraction of the rays traditionally shot. The undersampled image is then reconstructed using algorithms from image processing. We demonstrate that while this approach is able to significantly reduce the amount of computation it still maintains a high perceptual image quality.Item Multi-Modal Presentation of Work of Arts in Virtual Reality with Simulation of Multi-Mirror Reflection(The Eurographics Association, 2006) Livatino, S.; Cuciti, D.; Wojciechowki, A.; S. Battiato and G. Gallo and F. StancoThe use of different media such as photography and virtual reality combined with different presentation modalities may provide a user with an extraordinary tool for exploration and appreciation of real work of art. This is especially important in case of time-spatial works-of-art where the problem of functionalities presentation becomes much more demanding. The possibility offered by latest graphics machines has attracted the interest of researchers to investigate this new area. The goal of the presented work is the creation of a multi-modal presentation of a piece of contemporary art, tightening the relation between computer graphics and arts. The focus is on an application that it is capable to cope in real-time with simulation of mirror reflections, including multi-reflections. The results were very encouraging which led to optimistic conclusions with a wide range of options for future works.