Paul F. Lister

ARCO - an architecture for digitization, management and presentation of virtual exhibitions

A complete tool chain starting with stereo photogrammetry based digitization of artefacts, their refinement, collection and management with other multimedia data, and visualization using virtual and augmented reality is presented. Our system provides a one-stop-solution for museums to create, manage and present both content and context for virtual exhibitions. Interoperability and standards are also key features of our system allowing both small and large museums to build a bespoke system suited to their needs

The Image chip for high performance 3D rendering

The Image chip, which accelerates 3D rendering algorithms base on Bresenhams line drawing and Pinedas parallel polygon drawing algorithms, is discussed. With these algorithms, Image can directly draw lines, spans, and triangles in wireframe, hidden-line, and Gouraud-shading modes. Image also directly antialiases vectors or provides antialiasing information to enhance antialiasing of vectors or triangles. Images operation, separation into layers to maximize performance and simplify the input and output interfaces, and support of advanced rendering effects such as Phong shading and texture mapping are described. The designs of Images internal architecture, host interface, and memory interface are also described.<<ETX>>

An interactive visualisation interface for virtual museums

Cultural institutions, such as museums are particularly interested in making their collections accessible to people with physical disabilities. New technologies, such as Web3D and augmented reality (AR) can aid museums to respond to this challenge by building virtual museums accessible over the Internet or through kiosks located in accessible places within the museum. In this paper, we propose a prototype user-friendly visualisation interface that uses Web3D and AR techniques to visualise cultural heritage artefacts for virtual museum exhibitions. User interactions within the virtual museum are performed in an effective way with the help of assistive technology, so that users can feel completely related with the virtual museum artefacts and so benefit in terms of education and entertainment.

Augmented reality interface toolkit

This work proposes a high-level augmented reality interface toolkit that allows the combination of audiovisual information with a real world environment in an easy and interactive way. The system is based on MFC libraries, OpenGL, OpenAL, Microsoft Vision SDK and the vision tracking libraries from the well known ARToolKit. Simple and cost effective hardware complements the software solution. This AR interface toolkit can be used as an exemplar for the development of other applications. Users can interact with the presented information in several different ways. Realistic augmentation is also supported such as soft and hard shadows, without sacrificing the overall efficiency of the system. To illustrate the feasibility of our AR interface toolkit a cultural heritage application for museum environments is briefly presented.

Why step when you can run? Iterative line digitization algorithms based on hierarchies of runs

One challenge for computer graphics and scientific visualization is to develop techniques to more effectively display and analyze the vast amounts of information we are collating, a race we are currently losing. To meet this goal, a key initiative suggests moving away from small-scale, low-resolution displays to immersive, high-fidelity systems. These environments permit higher levels of interactivity and exploration, but require more power and bandwidth than current graphics systems can deliver. The move to larger and/or higher resolution displays will place a greater emphasis on the digitization algorithms we employ for even the simplest geometrical primitives. In this tutorial, we present a technique to describe and digitize the line as a set of runs, runs of runs, runs of runs of runs, and so on, in fact, as any level of runs within the full hierarchy of runs in the digital line. The digitization algorithms we present apply to a broad range of resolutions and applications, including geometric scan conversion, ray traversal, linear mapping and interpolation.

Performance of Space Subdivision Techniques in Ray Tracing

Whilst providing images of excellent quality, ray tracing is a computationally intensive task. The first part of this paper compares the speed‐up achieved in ray tracing using various space subdivision algorithms and discusses the implications of implementing the algorithms on parallel processing systems. The second part addresses the problem of building the data structure within the rendering process, a situation which occurs when the rendering process is parallelised and dynamic scenes are rendered. Greater performance can be achieved with dynamic structure building compared to creation of the structure prior to rendering. The dynamic building algorithm proposed reduces the building time and storage cost of space subdivision structures, and decreases the data structure creation‐render cycle time, thus enhancing image parallelism performance.

Implementing an anisotropic texture filter

Abstract Texture mapping is an important operation in high-quality computer graphics applications. The principles of image filtering are well established and understood and several high-quality texture filtering algorithms have been developed. However, these have tended to be either off-line software implementations or based on high-end computer graphics rendering systems. Current generation PC-based graphics acceleration utilises texture pre-filtering techniques based upon an isotropic filter kernel. The most common implementations are those based on MIP-map texture storage and bilinear or trilinear interpolation. Such filters give a reduction in image aliasing at the expense of introducing blurring. As acceleration hardware performance improves, tolerance of such compromises is falling leading to the adoption of “anisotropic” filtering solutions. In this paper we present a detailed description of a low-cost implementation of an anisotropic filtering unit for use within a contemporary graphics pipeline. The filter is shown to produce improved visible results for only a modest increase in hardware cost.

Codesign of graphics hardware accelerators

The design of a hardware architecture for a computer graphics pipeline requires a thorough understanding of the algorithms involved at each stage, and the implications these algorithms have on the organisation of the pipeline architecture. The choice of algorithm, the flow of pixel data through the pipeline, and bit width precision issues are crucial decisions in the design of new hardware accelerators. Making these decisions correctly requires intensive investigation and experimentation. The use of hardware description languages such as VHDL, allow for sound top down design methodologies, but their effectiveness in such experimental work is limited. This paper discusses the use of software tools as an aid to hardware development and presents applications that demonstrate the possibilities of this approach and the benefits that can be attained from an integrated codesign design environment. CR

A Virtual Interactive Teaching Environment (VITE) using XML and Augmented Reality

We present a new approach to the teaching of top-down design of VHDL using a novel virtual interactive teaching environment. This environment enables students to learn more effectively using virtual multimedia content, while exploiting XML, and augmented reality. This environment can be adapted for teaching of other subject areas.

ARCOLite-an XML based system for building and presenting virtual museum exhibitions using Web3D and augmented reality

This paper describes ARCOLite, our low cost XML based client-server architecture for building and presenting digital heritage content in virtual museums. Our system includes components for creation and refinement of virtual artefacts including virtual reconstruction of buildings; XML content management, XML technologies for content repositories and presentation; and content visualisation using Web3D, virtual and augmented reality