Browsing Volume 13 (1994) by Issue Date
Now showing items 1-20 of 69
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Making Shaders More Physically Plausible
(Blackwell Science Ltd and the Eurographics Association, 1994)There is a need to develop shaders that not only"look good", but are more physically plausible. From physical and geometric considerations, we review the derivation of a shading equation expressing rejected radiance in ... -
A Survey of Shading and Reflectance Models
(Blackwell Science Ltd and the Eurographics Association, 1994)Since the beginning of computer graphics, three decades ago, a large number of models intended to describe the behaviour of light on a given point of a surface have been proposed. Almost every author uses his own terminology ... -
Strands, Gravity and Botanical Tree Imagery
(Blackwell Science Ltd and the Eurographics Association, 1994)This paper presents a technique for the modelling and rendering of realistic botanical tree images. A strand model is used that is analogous to the internal vascular structure of a tree. The model is"grown" under the ... -
Constant-Time Filtering by Singular Value Decomposition?
(Blackwell Science Ltd and the Eurographics Association, 1994)We present a technique implementing space-variant filtering of an image, with kernels belonging to a given family, in time independent of the size and shape of the filter kernel support. The essence of our method is efficient ... -
Computer Generated Copper Plates
(Blackwell Science Ltd and the Eurographics Association, 1994)Making computer generated copper plates with image generation algorithms is presented. The method uses a kind of volume texturing in connection with image processing algorithms, and is suitable for implementation in a ray ... -
Wavelet Projections for Radiosity
(Blackwell Science Ltd and the Eurographics Association, 1994)One important goal of image synthesis research is to accelerate the process of obtaining realistic images using the radiosity method. Two important concepts recently introduced are the general framework of projection methods ... -
Experiments in the Parallel Computation of 3D Convex Hulls
(Blackwell Science Ltd and the Eurographics Association, 1994)Two parallel implementations of a 3D convex hull algorithm are reported. The paper considers a MIMD distributed memory architecture and the implementations are carried out on the Meiko Computing Surface using T800 transputers ... -
Classification of Ray-Generators in Uniform Subdivisions and Octrees for Ray Tracing
(Blackwell Science Ltd and the Eurographics Association, 1994)Spatial subdivisions cause an enormous acceleration of ray tracing due to the reduction of ray-object intersections. For this purpose it is necessary to generate the sequence of ray-cells (all cells met consecutively by a ... -
Five-dimensional Adaptive Subdivision for Ray Tracing
(Blackwell Science Ltd and the Eurographics Association, 1994)This paper presents a directional subdivision method for speeding up ray tracing. This method is easy to use, because it automatically adapts the subdivision to the scene relieving the user from having to set parameters ... -
A Theoretical Framework for Physically Based Rendering
(Blackwell Science Ltd and the Eurographics Association, 1994)In this paper we introduce the concept of the global reflection distribution function which allows concise formulation of the global illumination problem. Unlike previous formulations it is not geared towards any specific ... -
A Data Structure for Artificial Terrain Generation
(Blackwell Science Ltd and the Eurographics Association, 1994)This paper addresses the problems of maintaining the consistency of spatial data under recursive subdivision algorithms for artificial terrain generation. Fractal modelling techniques are outlined, with particular reference ... -
Controllable Locality in C2 Interpolating Curves by B2-splines / S-splines
(Blackwell Science Ltd and the Eurographics Association, 1994)This paper presents a systematic scheme for controlling the local behaviour of C2 interpolating curves, based on the cubic B2-splines and the quartic S-splines. Both splines have an additional control point obtained by ... -
Animation using NURBS
(Blackwell Science Ltd and the Eurographics Association, 1994)All animation, whether generated by pen or processor, is concerned with the changing behaviour of synthetic actors through time. Computer animation has allowed an animator to regard different actors as functionally equivalent ... -
Animations to Represent Multivariate Data
(Blackwell Science Ltd and the Eurographics Association, 1994)Building animations is a current practice to study problems in the computational and experimental sciences. There are several classes of applications which generate descriptions of complex phenomena, based on a large variety ... -
Ray Traversal of Spatial Structures
(Blackwell Science Ltd and the Eurographics Association, 1994)This article presents an efficient algorithm for ray traversal of uniform and hierarchical spatial structures. Only simple integer and logical operations are used. The problem of error accumulation during ray casting is ... -
An All-integer Algorithm for Drawing Anti-aliased Straight Lines
(Blackwell Science Ltd and the Eurographics Association, 1994)An algorithm for drawing anti-aliased straight lines based on Bresenharn sline algorithm is presented in this paper. Only integer calculations are required. Multiplications or divisions are not needed (only simple ... -
Computation of Offset Curves by the Huygens Principle
(Blackwell Science Ltd and the Eurographics Association, 1994)A new algorithm for computing offset curves is proposed. The algorithm is based on the Huygens principle for propagating wave-fronts. It automatically avoids the topological singularities that appear in conventional methods. ... -
The Design and Specification of a Visual Language: An Example for Customising Geographic Information Systems Functionalities
(Blackwell Science Ltd and the Eurographics Association, 1994)In this paper the design of a visual program editor and its specification using formal grammars are discussed. We consider an environment to specify, analyse and execute visual programs for a Geographical Information System ... -
Recovering a Smooth Boundary Representation from an Edge Quadtree and from a Face Octree
(Blackwell Science Ltd and the Eurographics Association, 1994)The Face Octrees are a representation scheme which is very suitable to represent both smooth free form surfaces and solids with smooth boundary, as well as, to perform operations among them. However, the Face Octree ... -
Deriving Spectral, Reflectance Functions of Computer-Simulated Object Colours
(Blackwell Science Ltd and the Eurographics Association, 1994)A method is presented which, given the RGB values of a colour stimulus displayed on a given cathode ray tube (to which a CIE XYZ triple corresponds), makes it possible to find a spectral reflectance function characterizing ...