VVG03

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https://diglib.eg.org/handle/10.2312/1029

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3D S.O.M.- A Commercial Software Solution to 3D Scanning
(The Eurographics Association, 2003) Baumberg, A.; Lyons, A.; Taylor, R.; Peter Hall and Philip Willis
This paper describes the novel features of a commercial software-only solution to 3D scanning - the 3D Software Object Modeller (3D S.O.M.). Our work is motivated by the desire to produce a low-cost, portable 3D scanning system based on hand-held digital photographs. We describe the novel techniques we have employed to achieve a robust software-based system in the areas of camera calibration, surface generation and texture extraction.
Applications of Clifford Algebra in Mixed Reality Environment
(The Eurographics Association, 2003) Ho, E.Y.T.; Peter Hall and Philip Willis
The 'beauty' of Clifford's Geometric Algebras is its ability to incorporate other algebras and it is the 'mother' algebra for all algebras. This paper introduces the advantage of using this algebra by combining and augmenting certain group of algebras, such as linear algebra, quaternion algebra, the Grassmann algebra and projective algebra to simplify mathematical manipulations in 3-dimensional rotations and projective geometry, especially in the context of mixed reality environment. Those 'augmented' representations are shown with applications in the mixed reality environment, especially for registration and computer vision based object recognition issues. Some simple scenarios with place-holder objects are described at the end for a full understanding of the mixed reality applications before other most recent engineering and computer science areas using this algebra for their applications are briefly discussed.
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.
Coding 3D Facial Models forMugshot Applications
(The Eurographics Association, 2003) Hyde, J.; Robinson, J.; Peter Hall and Philip Willis
Three-dimensional information about a human face may have some correlation with the colour information present in its flat texture image. In order to maximise the available information for human identification of faces, a variety of coding schemes based on Binary Tree Predictive Coding 5 (BTPC5) are proposed and evaluated against similar schemes applied to the JPEG coder. The results of these schemes are presented quantatively with some discussion of the subjective results.
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.
Digitisation to Presentation- BuildingVirtual Museum Exhibitions
(The Eurographics Association, 2003) Patel, M.; White, M.; Walczak, K.; Sayd, P.; Peter Hall and Philip Willis
We describe an innovative system designed for museums to create, manage and present multimedia based representations of museum artefacts in virtual exhibitions both inside and outside museums. Our system creates digital surrogates through a novel stereo photogrammetry system with little user interaction. The resulting 3D objects are refined using state-of-the-art 3D modelling software configured for ease of use by museum staff. A repository of such digital surrogates is managed in an XML enabled relational database and provides the basis for the creation and presentation of virtual museum exhibitions, allowing current museum websites to evolve from a 2D to a 3D multimedia-rich domain. In this paper, we discuss the modelling and refinement processes which are based on stereo photogrammetry and the creation and visualisation of virtual museum exhibitions using virtual and augmented reality techniques.
Efficient 3D Content Creation using Point Sampled Geometry
(The Eurographics Association, 2003) Gross, Markus; Peter Hall and Philip Willis
In recent years, point primitives have received a growing attention in computer graphics. The emergence of affordable 3D scanning devices along with the demand for ever more geometric detail has created the need to efficiently process and display very large point sampled models. At data sizes where triangle based methods approach their limits, point representations feature a variety of advantages. Since points provide a discretization of geometry without explicit storage of topology, they enable us to generate highly optimized object representations. In spite of the great challenges they pose for graphics processing, the latest generation of algorithms includes advanced modeling, sophisticated geometry processing, and high quality rendering. In this talk I will introduce points as a powerful and versatile graphics primitive for efficient 3D content creation and present a survey the latest research results in point based computer graphics. Novel concepts for the representation of point sampled shapes will be discussed, as well as algorithms for interactive modeling of point clouds. In addition, I will address methods for geometric processing, filtering and resampling of point models. I will also give examples of algorithms for high performance rendering of point clouds, including advanced shading, antialiasing, and transparency. Finally, I will introduce Pointshop3D, an open source software for 3D photo editing of point sampled geometry, which includes all of the presented algorithms.
An Eigenvector Method for Surface Recovery
(The Eurographics Association, 2003) Robles-Kelly, A.; Hancock, E.R.; Peter Hall and Philip Willis
In this paper we explore how spectral methods for graph seriation can be used to develop a new shape-fromshading algorithm. We characterise the field of surface normals using a transition matrix whose elements are computed from the sectional curvature between different image locations. We use a graph seriation method to define a curvature minimising surface integration path for the purposes of height reconstruction. To smooth the reconstructed surface, we fit quadric patches to the height data. The smoothed surface normal directions are updated ensuring compliance with Lambert's law. The processes of height recovery and surface normal adjustment are interleaved and iterated until a stable surface is obtained. We provide results on synthetic and real-world imagery.
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.
Extending Natural Textures with Multi-Scale Synthesis
(The Eurographics Association, 2003) Stahlhut, O.; Peter Hall and Philip Willis
This paper presents a texture synthesis algorithm that was designed for the tile-less generation of large images of arbitrary size from small sample images. The synthesised texture shows features that are visually similar to the sample over a wide frequency range. The development of the algorithm aimed at achieving high quality results for a large range of natural textures, incorporation of the original samples in the synthesis product, ease of use and good texturing speed even with input sample data two magnitudes larger than used by previous techniques. Like other algorithms we utilise an implicit texture model by copying arbitrary shaped texture patches from the sample to the destination over a multi-scale image pyramid. Our method combines the advantages of different previous techniques with respect to quality. A mixture of exhaustive searching, massive parallel computing and the well-known LBG-algorithm ensures a good balance between texturing quality and speed.
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.
Frontiers in 3D Photography: Reflectance and Motion
(The Eurographics Association, 2003) Seitz, Steve; Peter Hall and Philip Willis
The last decade has seen great progress in 3D shape capture technology, both in terms of research ad- vances and successful commercial systems. So why don't most people own 3D cameras? Aside from such issues as expense and size, there remain fundamental technical problems that restrict the applicability of the current state of the art. One of these problems is modeling realistic materials. If you look around, you'll notice that most objects are shiny and have specular highlights. However, virtually all shape recovery methods perform poorly for such surfaces. For this reason, it is common to paint an object white before scanning with a laser scanner. This limitation seems unnecessary, given that the human visual system appears to have no such problem{in fact, highlights should give us more information for shape inference. Another major limitation is that the 3D capture process is currently slow and laborious. In particular, very few techniques exist that can capture moving scenes. Obtaining accurate and complete models of moving scenes is challenging, due to the limited measurements that can be obtained at each instant in time. In this talk, I will describe new work from my research group that seeks to address these two problems{ modeling shiny scenes and moving scenes from photographs. We have recently developed shape capture methods that produce laser-scanner-quality results but for scenes with general re ective properties, including shiny surfaces and even anisotropic materials like brushed fur. I will also describe motion- scanning techniques that yield dense shape reconstructions of moving scenes.
Interpretation of Fuzzy Logic For Texture Queries in CBIR
(The Eurographics Association, 2003) Kulkarni, S.; Peter Hall and Philip Willis
This paper presents a novel fuzzy logic based approach for the interpretation of texture queries. Tamura feature extraction technique is used to extract each texture feature of an image in the database. A term set on each Tamura feature is generated by a fuzzy clustering algorithm to pose a query in terms of natural language. The query can be expressed as a logic combination of natural language terms and tamura feature values. The performance of the technique was evaluated on Brodatz texture benchmark database. Experimental results show that the proposed technique is effective and the retrieved images indicate that those images are suitable for the specific queries.
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.
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.
Lambertian Correction for Rough and Specular Surfaces
(The Eurographics Association, 2003) Robles-Kelly, A.; Hancock, E.R.; Peter Hall and Philip Willis
This paper describes a method for performing Lambertian reflectance for rough and specular surfaces. Rather than using an existing reflectance model, we present a method for estimating the reflectance function from image data. The method makes use of the Gauss map between a surface and a unit sphere. Under conditions in which the light source direction and the viewer direction are identical, we show how the reflectance function can be represented by a polar function on the unit sphere. We pose the problem of recovering the reflectance function as that of estimating a tabular representation of the polar function. A simple analysis shows how the tabular representation of the reflectance function can be obtained using the accumulative distribution of image gradients. By modifying the reflectance function and back-projecting, we can render the surface with alternative lighting models. Here, we choose to back-project a Lambertian reflectance model. This allows us to be remove specularities from shiny surfaces and compensate from boundary ''flattening'' for rough surfaces. We illustrate the utility of the method on a variety of real world imagery.
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.
A Novel Form of Pointing Device
(The Eurographics Association, 2003) Cantzler, H.; Hoile, C.; Peter Hall and Philip Willis
This paper presents a novel approach for man machine interaction applying real time computer vision techniques. We use a handheld camera to control the mouse cursor on a computer display. The camera captures an image of the display in its eld of view and this can be used to judge the camera's position and orientation relative to the display. The problem is modelled as a plane-to-plane projection (homography). Once the mapping of the display in the camera view to the real world display is known, the intersection between the central axis of the camera and the surface of the display can be computed. The mouse pointer is then moved to the corresponding display position. This calculation can be iterated continuously to update the mouse cursor position as the camera position and orientation changes. The camera can then be used to control the mouse cursor just like a laser pointer controls a laser dot. A prototype has been developed to demonstrate the approach.
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.
Organisation
(The Eurographics Association, 2003) Peter Hall and Philip Willis
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