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.
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.
2872475
Texturing and hypertexturing of volumetric objects
Texture mapping is an extremely powerful and flexible tool for adding complex surface detail to an object. This paper introduces a method of surface texturing and hypertexturing complex volumetric objects in real-time. We employ distance field volume representations, texture based volume rendering and procedural texturing techniques with Shader Model 2.0 flexible programmable graphics hardware. We aim to provide a flexible cross-platform, non vendor specific implementation.
6680702
Melting Objects
This paper describes a technique for producing realistic animations of melting objects. The work presented here introduces a method that accurately models both thermal flow and the latent heat during the phase change. The mechanism for energy transfer to the model is via both boundary conditions and radiation. Emphasis is made on accurately modelling the solid object and the method is particularly suited to rigid solids with complex surface geometry. The underlying objects are constructed using Volume Graphics modelling techniques (specifically voxelization), and a numerical simulation computes the time-dependent heat flow throughout the object. A technique for computing the phase transition is given, and details for rendering the melting objects are provided. The melting is controlled by material parameters, such as specific heat capacity, thermal conductivity, latent heat and temperature. Examples are given of melting ice and a plastic man.
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.
1777796
A System for the Non-Linear Modelling of Deformable Procedural Shapes
This paper describes a fully interactive modelling system, which we have called ClayWorks, for defining the implicit geometry of 3D objects using parametric base primitives and deformations. The goal of this system is to provide a means for describing object data and its creation history by using a series of parametric steps that can be modified post-creation in a non-linearmanner. The advantages of this approach are that unlike other modelling approaches, it enables compact object descriptions, an intuitive modelling process, a simple approach to multiresolution objects, real-time feedback during the modelling process and a render independent object representation.
15818085
An evaluation of integrated zooming and scrolling on small screens
Abstract Speed-dependent automatic zooming (SDAZ) has been proposed for standard desktop displays as a means of overcoming problems associated with the navigation of large information spaces. SDAZ combines zooming and panning facilities into a single operation, with the magnitude of both factors dependent on simple user interaction. Previous research indicated dramatic user performance improvements when using the technique for document and map navigation tasks. In this paper, we propose algorithmic extensions to the technique for application on small-screen devices and present a comparative experimental evaluation of user performance with the system and a normative scroll–zoom–pan interface. Users responded positively to the system, particularly in relation to reduced physical navigational workload. However, the reduced screen space reduced the impact of SDAZ in comparison to that reported in previous studies. In fact, for one-dimensional navigation (vertical document navigation) the normative interface out-performed SDAZ. For navigation in two dimensions (map browsing) SDAZ supports more accurate target location, and also produces longer task completion times. Some SDAZ users became lost within the information space and were unable to recover navigational context. We discuss the reasons for these observations and suggest ways in which limitations of SDAZ in the small-screen context may be overcome.
12891588
Implementing type classes
We describe the implementation of a type checker for the functional programming language Haskell that supports the use of type classes. This extends the type system of ML to support overloading (ad-hoc polymorphism) and can be used to implement features such as equality types and numeric overloading in a simple and general way.
The theory of type classes is well understood, but the practical issues involved in the implementation of such systems have not received a great deal of attention. In addition to the basic type checking algorithm, an implmenentation of type classes also requires some form of program transformation. In all current Haskell compilers this takes the form of dictionary conversion, using functions as hidden parameters to overloaded values. We present efficient techniques for type checking and dictionary conversion. A number of optimizations and extensions to the basic type class sytems are also described.
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.
34512114
Nanomanipulator applications in education: the impact of haptic experiences on students' attitudes and concepts
This research investigated educational uses of the nanoManipulator (nM) that when connected to an atomic force microscope allows students to get tactile feedback and manipulate objects such as viruses that are nanometer-sized. Our research focused on documenting how haptic feedback impacted students' attitudes as well as their understandings of viruses. The study involved 209 middle and high schools students. Half of the students received haptic feedback during investigations and half had the same investigations with the haptic feedback blocked by the computer. The results showed that students' with haptic feedback had better attitudes towards the investigations and were more likely to develop 3-dimensional concepts of adenoviruses that were more morphologically accurate.
40878593
Structured Development? A Structurational Analysis of the Development of an Executive Information System