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Computer Graphics, Imaging and Visualisation, 2007. CGIV '07

Date 14-17 Aug. 2007

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Displaying Results 1 - 25 of 91
  • Computer Graphics, Imaging and Visualisation - Cover

    Publication Year: 2007
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  • Computer Graphics, Imaging and Visualisation - Title page

    Publication Year: 2007 , Page(s): i - iii
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  • Computer Graphics, Imaging and Visualisation - Copyright notice

    Publication Year: 2007 , Page(s): iv
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  • Computer Graphics, Imaging and Visualisation - TOC

    Publication Year: 2007 , Page(s): v
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  • Preface

    Publication Year: 2007 , Page(s): xi
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  • Reviewers

    Publication Year: 2007 , Page(s): xii
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  • A Novel Adaptive Sampling by Tsallis Entropy

    Publication Year: 2007 , Page(s): 5 - 10
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (366 KB) |  | HTML iconHTML  

    Monte Carlo is the only choice of physically correct method to compute the problem of global illumination in the field of realistic image synthesis. Adaptive sampling is an appealing tool to eliminate noise, which is one of the main problems of Monte Carlo based global illumination algorithms. In this paper, we investigate the use of entropy in the domain of information theory to measure pixel quality and to do adaptive sampling. Especially we explore the nonextensive Tsallis entropy, in which a real number q is introduced as the entropic index that presents the degree of nonextensivity, to evaluate pixel quality. By utilizing the least-squares design, an entropic index q can be obtained systematically to run adaptive sampling effectively. Implementation results show that the Tsallis entropy driven adaptive sampling significantly outperforms the existing methods. View full abstract»

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  • Random Projection with Robust Linear Discriminant Analysis Model in Face Recognition

    Publication Year: 2007 , Page(s): 11 - 15
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (359 KB) |  | HTML iconHTML  

    This paper presents a face recognition technique with two techniques: random projection (RP) and robust linear discriminant analysis model (RDM). RDM is an enhanced version of fisher's linear discriminant with energy-adaptive regularization criteria. It is able to yield better discrimination performance. Same as Fisher's Linear Discriminant, it also faces the singularity problem of within-class scatter. Thus, a dimensionality reduction technique, such as principal component analysis (PCA), is needed to deal with this problem. In this paper, RP is used as an alternative to PCA in RDM in the application of face recognition. Unlike PCA, RP is training data independent and the random subspace computation is relatively simple. The experimental results illustrate that the proposed algorithm is able to attain better recognition performance (error rate is approximately 5% lower) compared to Fisherfaces. View full abstract»

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  • A Method Used To Dynamic Scene Management Based On Octree

    Publication Year: 2007 , Page(s): 16 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (231 KB) |  | HTML iconHTML  

    At present the most important things on scene rendering in computer graphics are fidelity and efficiency. In order to achieve these goals, a considerable number of applications require a data structure like a tree to manage the entire scene. Searching the scene means to traversal the tree and moving objects in the scene means to recreate the tree, which are very costly but unavoidable process. In this paper, we establish an octree for managing the whole scene and encode the nodes in the tree. Through a simple process of calculation from one node's code, we can get this node's adjacent nodes' code. With the orderly structure of the octree, we have obtained the target that is searching the nodes in the octree and recreating part of the octree efficiently. View full abstract»

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  • Cache-Oblivious Scanline Algorithm Design

    Publication Year: 2007 , Page(s): 22 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB) |  | HTML iconHTML  

    This paper introduces the concept of cache-oblivious scanline algorithms and their design issues to overcome the limitations of cache size and cache line-length within existing workstations, making them suitable for the visualisation of very large 3D data sets. Unlike the standard RAM model, the cache-oblivious model can tune cache parameters without knowing them to minimize cache misses and data movement among multiple levels of caches. View full abstract»

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  • Point Based Rendering of Implicit 4-Dimensional Surfaces

    Publication Year: 2007 , Page(s): 31 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1265 KB) |  | HTML iconHTML  

    We present a point based rendering algorithm that uses hyper-cubes to perform spatial subdivision in a 4D volume. A 4D function interval exclusion test is used to speed up the rendering of 4D Implicit surfaces in this hyper-volume. A 4D orthonormal basis function is used to define a 4D camera, which projects isometric or perspective views onto a plane in 4D for viewing. The technique requires evaluations of 4D implicit surface functions and gradients to render shaded images. The technique also allows for hidden surface elimination using a z-buffer modified for use in a 4D space. We give examples of its use in rendering some 4D surfaces and discuss problems with the technique. The algorithm can be generalised to higher dimensions. View full abstract»

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  • A Non-parametric Guide for Radiance Sampling in Global Illumination

    Publication Year: 2007 , Page(s): 41 - 48
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5141 KB) |  | HTML iconHTML  

    Global illumination as described by the radiance and potential equations is essentially a sampling problem. This sampling has two elements: 'where' to sample and 'how' to sample. In this paper we propose an alternative method to non-parametric ally simplify the problem of 'where' in the general case. We present a solid angle based uniform sampling scheme with an efficient conservative cull of solid angles not affecting the transfer of radiance between two surfaces. This construction also provides a geometric area bounds within which a surface can receive energy from another along directions contained in the solid angle. The technique can be used to illuminate a scene from a general emitter, including incident light fields. The method has several applications and advantages, with results showing good sampling efficiency and speed. View full abstract»

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  • A simple and quick method for rendering underwater optical effect

    Publication Year: 2007 , Page(s): 49 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1436 KB) |  | HTML iconHTML  

    Underwater optical effect simulation is an important part of simulating natural scene. However, computing these effects is difficult and time-consuming, since light refracts when passing through waves. To address the problem, this paper proposes a simple and quick method for rendering underwater scenes, including the shafts of light refracted by the dynamic water surface, caustics caused by the effects of light and shadows beneath the creatures in the water. The method simplifies the Iwasaki's method to save the computation-time by an eye-irrelative method calculating the intensities of the illumination volumes with parts of intersection points of Iwasaki's. As the experiment results show that our method got a high frame rate with an acceptable quality for real-time applications. View full abstract»

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  • A Visibility Field for Ray Tracing

    Publication Year: 2007 , Page(s): 54 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2108 KB) |  | HTML iconHTML  

    This paper presents a type of visibility data structure for accelerated ray tracing. The visibility field is constructed by choosing a regular point subdivision over a hemisphere to obtain a set of directions. Corresponding to each direction there is then a rectangular grid of parallel beams, with each beam referencing a set of identifiers corresponding to objects that intersect it. Objects lying along a beam are sorted using a 1D BSP along the beam direction. The beam corresponding to any ray can be looked up in small constant time and the set of objects corresponding to the beam can then be searched for intersection with the ray using an optimised traversal strategy. This approach trades off rendering speed for memory usage and pre-processing time. The data structure is also very suitable for hemisphere integration tasks due to its spherical nature and results for one such task - ambient occlusion - are also presented. Results for several scenes with various rendering methods are presented and compare favourably with a well established approach, the single-ray coherent ray tracing approach of Wald and Slusallek et al. View full abstract»

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  • A Case Study of Integrating Principles of Photography and Photorealistic for 3D Rendering

    Publication Year: 2007 , Page(s): 62 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    This paper discusses the hybrid technique of merging both principles of photography and photorealistic 3D rendering approach to create a harmony between the two elements. In order to optimize the performance of 3D rendering and provide a creative solution for effective rendering method, an experiment was conducted. Based on analysis of 3D rendering works, qualitative approach is selected and case study was conducted by comparing works through observation. The findings indicate the obvious difference in the understanding of basic design fundamentals accustomed in photography. The second phase of the research is targeted towards the students' maturity in understanding the content of photorealistic 3D in terms of model properties, textures, lighting and rendering. The outcome of the research serves as a guideline to understand the basic flow of efficient photorealistic 3D rendering process for beginners with enhanced method. View full abstract»

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  • Design and Implementation of a Multidimensional Zoomable Electronic Catalog

    Publication Year: 2007 , Page(s): 71 - 76
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1328 KB) |  | HTML iconHTML  

    Consumers select products based on a combination of decision criteria and preferences, such as price, quality, appearance, origin, and popularity. However, current interfaces for electronic catalogs do not adequately support the multi-criteria searching, browsing, and comparison tasks typical of consumer "bargain hunting" behavior. This paper presents the design and implementation of a visual interface for a large electronic catalog that represents products as a collection of images in a compact, zoomable, multidimensional grid. At the overview level, the spatial dimensions represent the price and quality tradeoffs that typically guide buying behavior. As a user zooms into regions of interest, the spatial dimensions are overloaded to represent additional decision criteria, such as product category and ratings. An empirical evaluation found that users preferred this new visual interface to a traditional tabular interface on measures of confidence, usability, and satisfaction, especially for multi-criteria comparison tasks. View full abstract»

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  • Estimation of Camera Parameters from a Single Moving Camera using Quaternion-based Interpolation of 3D Trajectory

    Publication Year: 2007 , Page(s): 77 - 80
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4276 KB) |  | HTML iconHTML  

    This paper presents a new quaternion-based method to estimate the camera parameters in a single video stream to interpolate 3D trajectory of the moving camera with camera parameters. We assume that the camera looks at three fixed points while translating and rotating in 3D space. To estimate the camera parameters, we get a set of nonlinear equations derived from a geometric perspective camera model. We have a large number of image frames to find each camera parameters while the number of unknown camera model parameters cannot be determined from a single frame. In order to solve this problem, we used interpolation to approximate camera movement in both translation and rotation. This was done using the concept of control node set at the specific frame in the video stream. The camera movement is based on acceleration level control while satisfying physical constraints. The control node is the set of variables used to determine acceleration-based interpolated equation used for data fitting. In this process, we used quaternion to interpolate orientation of the camera. The acceleration-based data fitting problem is solved using nonlinear parameter optimization solver, GRG2. Our experimental results show that this approach to estimate camera parameters and 3D trajectory of the camera moment is robust enough to handle image sequences of a common scene without sudden change in camera moment. View full abstract»

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  • How Psychophysical Perception of Motion and Image relates to Animation Practice

    Publication Year: 2007 , Page(s): 81 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    This paper investigates the difference between seeing and perceiving in animation. It analyses character design in the light of experiments in face recognition, in particular how iconic a character can be in design. It discusses whether a universal theory can be applied and if caricatures are really 'super-portraits' that echo how brains recall faces. The psychophysical perception of motion in animation is analysed in the light of animation principles such as 'squash and stretch' and 'isolation'. Using made and found examples, the paper looks at how signature movement and animation principles are now being supplemented or even supplanted by motion capture and posits what this means for animation in the future. The paper maps popular animation characters within two specially designed triangular charts for image and for motion. It analyses the resulting images in terms of perceived and received information, looking particularly at the region of empathic connection coined by Dr Masahiro Mori as the 'Uncanny Valley'. [1] By examining the different empathic demands motion capture makes on an audience it reaches the conclusion that both image and motion must be treated symbiotically for full analysis to be achieved. View full abstract»

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  • Quaternion-Based Camera Calibration and 3D Scene Reconstruction

    Publication Year: 2007 , Page(s): 89 - 92
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (425 KB) |  | HTML iconHTML  

    This paper deals with determining camera parameters for three dimensional scene reconstruction given an image with three known points on a single plane on the image. The problem is solved using a quaternion based set of nonlinear equations. The advantage of using quaternion is it can accelerate computation and allows us correct orientation interpolation, if needed, while avoiding degeneration in camera parameter interpolation. View full abstract»

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  • Keypad Inspection System of Cellular Phone

    Publication Year: 2007 , Page(s): 93 - 96
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    In this paper we describe a keypad inspection of cellular phones using image processing. Before keypad buttons are assembled, they occur problems such as surface chipping, color difference, and font errors under process. To solve these problems and to improve the quality of the products, automatic keypad inspection is required. This paper deals with development of inspection method so that objects are moved and rotated for matching to reference image, when objects are in random direction and location in images. And then, for inspecting defect of keypad button, all images of the same patterns of keypad buttons are sequentially matched by the proposed method. View full abstract»

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  • Video Game Console Audio: Evolution and Future Trends

    Publication Year: 2007 , Page(s): 97 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB) |  | HTML iconHTML  

    Rapidly advancing technologies and the increasing role of computers give the computer game boundless potential for the future. Among the various game industries, the console game industry in particular has attracted significant attention, bringing the importance of sound and music to the forefront. Game music was traditionally used for sound effects to prevent user boredom. As gaming developed, so did audio, being utilized for numerous purposes. As gaming platforms increased in power and complexity, audio, which was once limited to simple beeps, started to play a larger role, becoming back ground music (BGM) having quality at par with that of films. This paper discusses the evolution of video game console audio specifications and hardware, from simple 8-bit machines to future directions in the development of audio generators for game sound & music. View full abstract»

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  • Improvement of Collision Detection Performance of Hierarchies by Using Dynamic-Density of 3D Objects Based on LOD (Level-of-Detail)

    Publication Year: 2007 , Page(s): 103 - 108
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (431 KB) |  | HTML iconHTML  

    This paper is many studies have been conducted focusing on standard objects in 3D space for quick and exact collision detection in 3D graphics. A great deal of these took interest in the improvement of performance speed of collision detection of 3D objects, and in realization of realistic expressions along with the marvelous advancement of 3D graphics hardware. In this paper, features of various collision detection algorithms for standard 3D objects among 3D graphic algorithms were analyzed, and a 'dynamic density' that utilizes the center value and corner points of standard objects in simple hierarchic structures of existing 3D objects is suggested. By using this algorithm, an LOD (level-of-detail) algorithm can be applied to 3D space to improve collision detection of 3D objects in a 3D space. Also, through suggesting efficient rendering of 3D dimensional spaces as an important element of 3D graphics and a realistic expression method, the realism and efficiency of 3D games, which regards the real-time element as an important one, can be greatly improved. View full abstract»

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  • Designing a Computer Game to Teach Einstein's Theory of Relativity

    Publication Year: 2007 , Page(s): 109 - 114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB) |  | HTML iconHTML  

    This paper describes an ongoing project to build a computer application that presents Einstein's theory of relativity in an interactive game environment. With the current interest in the use and study of how computer games can help teach and educate, so-called 'serious games', the resulting game is expected to have value for educators in communicating the concepts of relativity to high school students as well as introducing the topic to a wider audience. The focus of this paper is on the initial design and building of an asteroids-styled game and describes features of the physics, graphics and animations, and play mechanics. Directions for future development and studies are discussed. View full abstract»

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  • Parallel processing between GPU and CPU: Concepts in a game architecture

    Publication Year: 2007 , Page(s): 115 - 120
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    This paper presents a new game loop architecture concept that employs graphics processors (GPUs) for general- purpose computation (GPGPU). A critical issue in this field is the concept of process distribution between CPU and GPU. The presented architecture consists in a very efficient model for distribution, and it was mainly designed to support math and physics on the GPU, but any kind of generic computation can be easily adapted. View full abstract»

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  • The Research About Xuan-Paper Model in the Simulation of Chinese Painting

    Publication Year: 2007 , Page(s): 121 - 125
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (479 KB) |  | HTML iconHTML  

    The Xuan-paper modeling, the most basic problem in Chinese painting simulating, is explored in this paper. An effective thickness Xuan-paper model is presented. The important influence of paper thickness to water holding and water transmitting is considered; also the complexity of mathematic solving caused by 3D paper model is avoided. The experimental results demonstrate that the model is simple and effective, and the model can simulate the different quality Xuan-papers by controlling the corresponding parameters. The effective Xuan-paper model establishes the foundation for simulating of water and ink moving in future. View full abstract»

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