Eurographics Partner Events

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Enhanced Texture Editing using Self Similarity
(The Eurographics Association, 2003) Brooks, S.; Cardle, M.; Dodgson, N.A.; Peter Hall and Philip Willis
Texture mapping is an indispensable tool for achieving realism in computer graphics. Significant progress has been made in recent years with regards to the synthesis and editing of 2D texture images. However, the exploration of user control for semi-automatic texture editing remains an open area of research. We present methods that partially address the semantic and technical limitations of Self-Similarity Based Editing. This is achieved by providing the user with more control over the similarity metric during editing and over spatial rearrangement during cloning.
Parameter Acquisition of Geometric Primitives within Virtual Environments for Internet-Based Telerobotics
(The Eurographics Association, 2003) Tan, J.; Clapworthy, G.; Peter Hall and Philip Willis
With the aim of improving the efficiency of on-line modelling of virtual environments (VEs) in Internet-based telerobotics (IBT), this paper addresses the modelling of geometric primitives using only a single view of them. By studying the properties and constraints of the primitives under perspective projection, we propose a modelling framework that uses virtual features as matching templates for the parameter acquisition of 3D objects, the analytical descriptions of which are hard to find.
Semi-Automated Logging for Professional Media Applications
(The Eurographics Association, 2003) Mateer, J.W.; Robinson, J.A.; Peter Hall and Philip Willis
We report a novel method for logging and annotating video footage specifically for professional post-production and archivist end users. SALSA - Semi-Automated Logging with Semantic Annotation - is a hybrid system that utilises automated footage analysis for cut detection and camera movement classification, in conjunction with a stenographic-like keyboard input system to enable the logging of higher-level semantic information. Output is presented in both standard printed log form, with the addition of mosaic visual representations of shots, and in a fully searchable database. Results from preliminary experiments are reported.
On the Editing of Images: Selecting, Cutting and Filling-in
(The Eurographics Association, 2003) Labrosse, F.; Peter Hall and Philip Willis
This paper is two-fold. On the one hand, we present a system using qualitative spatial reasoning to help a user choose parts of an image that form interesting objects. The system then allows the user to cut these parts as if unwanted in the original image. On the other hand, we propose a modi cation of existing texture synthesis methods to create texture in the holes left by the cutting of previously selected areas of the image. This texture synthesis is constrained so that it creates boundaries between regions that are similar to existing ones and lls-in the created regions, yet producing random enough textures so that the new image looks realistic. The context of this work is post-production special e ects in cinema or image manipulation where one often wants to remove parts of an image, e.g. when they correspond to props needed for the lming or objects inadvertently included in the shot.
Investigating Occlusion and Discretization Problems in Image-Based Blurring Techniques
(The Eurographics Association, 2003) Barsky, Brian; Peter Hall and Philip Willis
Traditional computer graphics methods render images that appear sharp at all depths. Adding blur can add realism to a scene, provide a sense of scale, and draw a viewer's attention to a particular region of a scene. Our image based blur algorithm needs to distinguish whether a portion of an image is either from a single object or is part of more than one object. This motivates two approaches to identify objects after an image has been rendered. We illustrate how these techniques can be used in conjunction with our image space method to add blur to a scene.
A Flexible and Versatile Studio for Synchronized Multi-View Video Recording
(The Eurographics Association, 2003) Theobalt, C.; Li, M.; Magnor, M.A.; Seidel, H.-P.; Peter Hall and Philip Willis
In recent years, the convergence of computer vision and computer graphics has put forth new research areas that work on scene reconstruction from and analysis of multi-view video footage. In free-viewpoint video, for example, new views of a scene are generated from an arbitrary viewpoint in real-time using a set of multi-view video streams as inputs. The analysis of real-world scenes from multi-view video to extract motion information or reflection models is another field of research that greatly benefits from high-quality input data. Building a recording setup for multi-view video involves a great effort on the hardware as well as the software side. The amount of image data to be processed is huge, a decent lighting and camera setup is essential for a naturalistic scene appearance and robust background subtraction, and the computing infrastructure has to enable real-time processing of the recorded material. This paper describes our recording setup for multi-view video acquisition that enables the synchronized recording of dynamic scenes from multiple camera positions under controlled conditions. The requirements to the room and their implementation in the separate components of the studio are described in detail. The efficiency and flexibility of the room is demonstrated on the basis of the results that we obtain with a real-time 3D scene reconstruction system, a system for non-intrusive optical motion capture and a model-based free-viewpoint video system for human actors.
API Design for Adaptive Subdivision Surfaces
(The Eurographics Association, 2003) Sovakar, A.; Studnitz, A. von; Kobbelt, L.; Dirk Reiners
We present an API for adaptive subdivision schemes which is generic in the sense that it allows to define a composite subdivision operator as a sequence of atomic splitting and averaging rules. The API encapsulates a mesh data structure enhanced by additional temporary information which is necessary to enable the refinement of mesh faces in random order while keeping the mesh structure consistent and avoiding redundant computations.
Advanced Environment Mapping in VR Applications
(The Eurographics Association, 2003) Kautz, Jan; Daubert, Katja; Seidel, Hans-Peter; Dirk Reiners
In this paper, we propose an approach for rendering diffuse and glossy reflections using environment maps. This approach is geared towards VR applications, where realism and fast rendering is important. We exploit certain mathematical properties of diffuse reflections and certain features of graphics hardware for glossy reflections. This results in a very fast, single-pass rendering algorithm, which even allows to dynamically vary the incident lighting.
Real-Time Per-pixel Rendering of Bump-mapped Textures Captured using Photometric Stereo
(The Eurographics Association, 2003) Robb, M.; Spence, A.D.; Chantler, M.J.; Timmins, M.; Peter Hall and Philip Willis
We present recent results from an EPSRC funded project VirTex (Virtual Textile Catalogues). The goal of this project is to develop graphics and image-processing software for the capture, storage, search, retrieval and visualisation of 3D textile samples. The ultimate objective is to develop a web-based application that allows the user to search a database for suitable textiles and to visualise selected samples using real-time photorealistic 3D animation. The innovation in this work is the combined use of photometric stereo and real-time per-pixel rendering for the capture and visualisation of textile samples. Photometric stereo is a simple method that allows both the bump map and the albedo map of a surface texture to be captured digitally. When imported into a standard graphics program these images can be used to provide 3D models with a photorealistic appearance. We have developed software that takes advantage of the advanced rendering features of consumer graphics accelerators to produce bump mapped models in real-time. The viewer can manipulate both viewpoint and lighting to gain a deeper perception of the properties of the textile sample.
OpenManip: An Extensible Cross-Scene-Graph Framework for Direct Object Manipulation
(The Eurographics Association, 2003) Braitmaier, Michael; Weiler, Manfred; Ertl, Thomas; Dirk Reiners
In this paper we describe a framework that exploits 3D widgets in order to allow for the direct manipulation of scene graph objects. The design of the frameworks is inspired by the OpenInventor manipulator functionality, but additionally emphasizes transparency from the underlying scene graph system, by separating core functionality from a relatively lean scene graph abstraction layer. Thus, the framework features different scene graph APIs, in particular OpenSG and Cosmo3D. Using our framework manipulation functionality can be easily integrated into any existing application since it only introduces a few new objects that have to be connected to the application. Our framework provides different manipulators for selection, scaling, rotation, and translation of objects. Moreover a set of editors allows for the manipulation of light and material properties. We demonstrate the extensibility of our framework both, in terms of customized manipulators and porting the framework to new scene graph APIs, which is supported by a clear object-oriented structure.
Studying the Fidelity Requirements for a Virtual Ballet Dancer
(The Eurographics Association, 2003) Neagle, R.J.; Ng, K.; Ruddle, R.A.; Peter Hall and Philip Willis
Teaching dance, especially ballet, usually involves the phrase: 'watch, copy and learn' and improvement is made by emulation. This involves not only how to achieve the steps but also the quality of the movement. In this paper, we present research into the fidelity that is required for a virtual ballet dancer driven by dance notation and its affect on the users ability to distinguish between expressive movement. The overall aim is to create a visualisation system that professionals could use to understand not only the choreography, but the expressive movement when resurrecting ballet scores and would be of benefit to teaching dance at all levels. Using Laban's effort theory to characterise the motion, this paper highlights the importance of the time factor to differentiate emotions. Two experiments are discussed that were designed to identify the accuracy of distinguishing emotions in ballet at lower levels of fidelity. The first experiment analyses the affect of the visual appearance on a 2D display and the second experiment looks into aspect of realism in the movement between keyframes defined by a dance notation. This paper explores understanding the quality of movement required for a virtual dancer, specifically, the expressivity encapsulated in the motion between key poses.
TRIPS - A Scalable Spatial Sound Library for OpenSG
(The Eurographics Association, 2003) Neumann, Tomas; Fünfzig, Christoph; Fellner, Dieter W.; Dirk Reiners
We present a Sound Library that is scalable on several computers and that brings the idea of a self-organized scenegraph to the Sound Library's interface. It supports the implementation of audio features right from the start at a high productivity level for rapid prototypes as well as for professional applications in the immersive domain. The system is built on top of OpenSG12 which offers a high level of functionality for visual applications and research, but does not come with audio support.We show and compare the effort to implement audio in an OpenSG application with and without TRIPS. Today's audio systems only accept raw 3D-coordinates and are limited to run on the same computer and the same operating system than the application runs on. Breaking these constraints could give developersmore freedom and ease to add high-quality spatial sound to their software. Therefore, users benefit from the promising potential OpenSG offers.
Prometheus: Facial Modelling, Tracking and Puppetry
(The Eurographics Association, 2003) Thorne, J.M.; Chatting, D.J.; Peter Hall and Philip Willis
The Prometheus project sought to create a real-time production chain for 3D content. This paper summarises the techniques that were developed for facial modelling, tracking and puppetry. The process used for creating photo-realistic models from images of the face is discussed along with the creation of a real-time markerless facial feature tracker, highlighting the methods for extracting pose, detecting the shape of the mouth and interpreting the occurrence of skin wrinkling. The conversion of tracking data to useable animation is also addressed.
An Occlusion Culling Toolkit for OpenSG PLUS
(The Eurographics Association, 2003) Staneker, Dirk; Dirk Reiners
Image-space occlusion culling is an useful approach to reduce the rendering load of large polygonal models in scienti c computing, mechanical engineering, or virtual medicine. Like most large model techniques, occlusion culling trades overhead costs with the rendering costs of the possibly occluded geometry. In this paper we present an occlusion culling toolkit for OpenSG. The toolkit includes three different image space techniques utilizing graphics hardware. These techniques are supported by other software techniques to optimize the occlusion culling queries. All techniques are conservative and usable with dynamic scenes, because no precomputing is necessary.
The OpenRT Application Programming Interface - Towards A Common API for Interactive Ray Tracing
(The Eurographics Association, 2003) Dietrich, Andreas; Wald, Ingo; Benthin, Carsten; Slusallek, Philipp; Dirk Reiners
For more than a decade now, interactive graphics has been shaped by triangle rasterization technology and the corresponding OpenGL graphics API. Since recently, however, interactive ray tracing is becoming a reality, and is slowly becoming available on several different hardware platforms. Due to its superior scalability, usability and efficiency, it is likely to play an increasingly important role in future interactive graphics applications. Though it would be desirable to drive this technology with a well-known API such as todays quasi-standard OpenGL interface, this would be complicated due to OpenGL's tight coupling to rasterization technology, which makes it less suitable for ray tracing. In this paper, we propose a new application programming interface called OpenRT. This new API is designed to be as similar to OpenGL as possible, while emphasizing the strength of interactive ray tracing. While being as simple to learn and use as OpenGL, OpenRT offers all the advantages of ray tracing, like implicit visibility culling, instantiation, the freedom to shoot arbitrary rays, and fully programmable shading.
Models from Image Triplets using Epipolar Gradient Features
(The Eurographics Association, 2003) Vincent, É.; Laganière, R.; Peter Hall and Philip Willis
In an application where sparse matching of feature points is used towards fast scene reconstruction, the choice of the type of features to be matched has an important impact on the quality of the resulting model. In this work, a method is presented for quickly and reliably selecting and matching points from three views of a scene. The selected points are based on epipolar gradients, and consist in stable image features relevant to reconstruction. Then, the selected points are matched using edge transfer, a measure of geometric consistency for point triplets and the edges on which they lie. This matching scheme is invariant to image deformations due to changes in viewpoint. Models drawn from matches obtained by the proposed technique are shown to demonstrate its usefulness.
Towards A 3D Virtual Studio for Human Appearance Capture
(The Eurographics Association, 2003) Starck, J.; Hilton, A.; Peter Hall and Philip Willis
This paper introduces the concept of a ''3D Virtual Studio'' for human appearance capture, akin to the motion capture studio for human motion tracking. Ultimately the 3D Virtual Studio should enable video-realistic reconstruction of a moving person from any viewpoint. A mesh-based stereo technique is presented to reconstruct a moving person from multiple camera views. This technique optimises a surface mesh to match stereo and silhouette data in a constrained coarse-to-fine framework, recovering sub-pixel image correspondence in the presence of inexact camera calibration. We compare this approach for scene reconstruction to conventional shape from silhouette and multiple view stereo. We then demonstrate view-dependent rendering and show improved resolution with the recovered image correspondence. We then demonstrate how this approach can be used to capture the dynamic shape and appearance of a computer graphics model of a person.
Cartoon-Style Rendering of Motion from Video
(The Eurographics Association, 2003) Collomosse, J.P.; Hall, P.M.; Peter Hall and Philip Willis
The contribution of this paper is a novel non-photorealistic rendering (NPR) system capable of rendering motion within a video sequence in artistic styles. A variety of cartoon-style motion cues may be inserted into a video sequence, including augmentation cues (such as streak lines, ghosting, or blurring) and deformation cues (such as squash and stretch or drag effects). Users may select from the gamut of available styles by setting parameters which in uence the placement and appearance of motion cues. Our system draws upon techniques from both the vision and the graphics communities to analyse and render motion and is entirely automatic, aside from minimal user interaction to bootstrap a feature tracker. We demonstrate successful application of our system to a variety of subjects with complexities ranging from simple oscillatory to articulated motion, under both static and moving camera conditions with occlusion present. We conclude with a critical appraisal of the system and discuss directions for future work.
Iterative Multi-Planar Camera Calibration: Improving Stability using Model Selection
(The Eurographics Association, 2003) Vigueras, J.F.; Berger, M.-O.; Simon, G.; Peter Hall and Philip Willis
Tracking, or camera pose determination, is the main technical challenge in numerous applications in computer vision and especially in Augmented Reality. However, pose computation processes commonly exhibit some fluctuations and lack of precision in the estimation of the parameters. This leads to unpleasant visual impressions when augmented scenes are considered. In this paper, we propose an efficient and reliable method for real time camera tracking which avoid unpleasant statistical fluctuations. This method is based on the knowledge of a piecewise planar structure in the scene and makes use of model selection to reduce fluctuations. Videos are attached to this paper which prove the effectiveness of our approach.
Collaborative Vision and Interactive Mosaicing
(The Eurographics Association, 2003) Robinson, J.A.; Peter Hall and Philip Willis
I propose criteria for collaborative vision applications where a camera user/operator and a computer work together to analyse a scene. An example of how these may be fulfilled is provided in IMP - an interactive mosaicing program.IMP generates mosaics in real-time, interacting with the user to cue camera movement and relay performance in-formation.

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