18996618
The Production of Volume Data from Triangular Meshes Using Voxelisation
Voxelisation is the term given to the process of converting data from one source type into a three dimensional volume of data values. The techniques known collectively as volume visualisation can then be applied to the data in order to produce a graphical representation of the object. This paper gives a practical approach to the voxelisation of data in the form of triangular meshes, and demonstrates the use of the method on various datasets. Visualisation is achieved by a method also described in the paper.
41482626
A New Approach to the Construction of Surfaces from Contour Data
This paper presents a new approach to the construction of a surface from a stack of contour slices. Unlike most existing methods, this new approach handles ambiguous conditions consistently without employing an algorithm to establish a correspondence between vertices on one contour and those on the next. It is easy to implement and fast to compute, requiring only basic geometric properties, namely closedness and simplicity, to be available with contour data. The advantages of this new approach have also been demonstrated with solutions to a few classical problems from the literature and some practical problems in medical imaging. It can also be applied to geographical surveying and keyframe animations.
18480565
Volumes of expression: artistic modelling and rendering of volume datasets
This paper presents the design and implementation of artistic effects in modelling and rendering of volume datasets. Following different stages of a volume-based graphics pipeline, we examine various properties of volume data, and illustrate how expressive and non-photorealistic effects can be implemented. We demonstrate that the true 3D nature of volume data makes it particularly applicable for this use, allowing the addition of complex effects at the modelling stage as well as during rendering.
153985
Facial Reconstruction Using Volumetric Data
In this paper we demonstrate computer aided techniques in the area of the reconstruction of facial features from skeletal remains. We outline the desired features of a system for skull identification, and demonstrate our progress in the area which builds upon our previous work on distance fields for volumetric data. In addition to the application we demonstrate an accurate 3D closing operator in practise on large data sets, cross correlation for automatic feature detection, and the current output from the technique which uses a 2D warp of the 3D distance field.
10888216
Hypertexturing complex volume objects
This paper will examine hypertexture rendering techniques and will demonstrate how volume data sets may be adapted in order for hypertexture to be applied. Details are given of a process for the conversion of complex objects, such as CT scans, into accurate distance fields. Hypertexture is applied to these objects and example renderings include the UNC CThead, a chess piece, a dodecahedron and a tank. Additional information is given about soft objects, density modulation functions, ray marching and controlling hypertexture application.
2186746
3D distance fields: a survey of techniques and applications
A distance field is a representation where, at each point within the field, we know the distance from that point to the closest point on any object within the domain. In addition to distance, other properties may be derived from the distance field, such as the direction to the surface, and when the distance field is signed, we may also determine if the point is internal or external to objects within the domain. The distance field has been found to be a useful construction within the areas of computer vision, physics, and computer graphics. This paper serves as an exposition of methods for the production of distance fields, and a review of alternative representations and applications of distance fields. In the course of this paper, we present various methods from all three of the above areas, and we answer pertinent questions such as How accurate are these methods compared to each other? How simple are they to implement?, and What is the complexity and runtime of such methods?.
3280299
Obituary for a Fax
Abstract: The continual failure of personal technology highlights the growing problem of obsolete, irreparable and non-recyclable toxic waste. Moore’s Law is a symptom of failure as much as a promise of better technology. Better design could avoid the problems.
9893455
Interactive Modelling in Decision Support Systems
Abstract In the past, the use of computer models in decision support has involved the interpretation of written reports derived from the output of the model. In recent years, however, the development of micro-computers and istributed computing systems has made it possible for decision-makers to be provided, not with a written report, but with a copy of the model itself. The new relationship between the user and the model, which this development establishes, has important implications for the way in which decision support systems (DSSs) are designed and used.
802922
Exploring Small Screen Digital Library Access with the Greenstone Digital Library
In recent years, the use of small screen devices has multiplied rapidly. This paper covers a number of different issues which arise when digital libraries are used in combination with such displays. Known limitations of small screens are presented to the Digital Library community. Two evaluations of pilot small-screen DL systems are presented, with some unexpected cultural and socio-technical concerns which arose. The pilot systems also demonstrate the delivery of small-screen access using an existing popular DL system.
18345527
Groupware and the Social Infrastructure of Communication
Communication technologies can supplement, but never supplant, the value of social bonds and trusting relationships.
43107545
A Theory of Qualified Types
Abstract This paper describes a general theory of overloading based on a system of qualified types. The central idea is the use of predicates in the type of a term, restricting the scope of universal quantification. A corresponding semantic notion of evidence is introduced and provides a uniform framework for implementing applications of this system, including Haskell style type classes, extensible records and subtyping. Working with qualified types in a simple, implicitly typed, functional language, we extend the Damas-Milner approach to type inference. As a result, we show that the set of all possible typings for a given term can be characterized by a principal type scheme, calculated by a type inference algorithm.