Search Results

Now showing 1 - 10 of 28
  • Item
    Moving Picture Synthesis at Linkoping University
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Fahlander, Olov
    We believe that in the future we will see a diverse variety of applications in the now emerging technology of real time computer animation. Such animations impose stringent computational and bandwidth demands on the underlying system. It is important to investigate carefully the methods best suited to the particular requirements of animation when motion is involved.1,2,3 In this paper we describe a system - Retina - which is now operational. We discuss the underlying concept of parameterization, which is of fundamental importance to the software design. Some timing data for this system will be given. A short description of the 3D editor, which is currently under development, is also given.
  • Item
    Report of the Timberline Meeting of ISO TC97/SC21/WG2 "Computer Graphics"
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Bono, Peter R.
  • Item
    Concerning the Specification of User Interfaces
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Duce, D. A.
  • Item
    User Interaction with an Environment for Image Processing and Graphics
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Westrup, T D; Kegel, W.; Gras, J.
    The Space Telescope Faint Object Camera is one of the most exciting projects in astronomical history, and will expand the volume of the observable universe by a factor of almost one thousand. In order to process the images from this instrument a FOC Image Processing System (FIPS) has been developed at the European Space Technology Centre (ESTEC) in Holland.Amongst other features, such as means to input, display, store, retrieve and output image and graphics data, FIPS places much emphasis on the user interface. The FIPS Command Language (FCL) is based on algorithmic languages such as PASCAL, C, ALGOL, etc, rather than conventional Job Control Languages, and thus includes control statements, compound statements, functions and procedures, assignment statements, etc. These allow the user to define complex functions out of the basic commands and to process for example, sets of images and graphics files without intervention.In addition, FCL allows command parameters to be specified either by default, canonically, by means of keywords, or via prompts to take account of the experience of the user. HELP information can be invoked both at the command and parameter levels, to assist the inexperienced user. As image processing can be time consuming, certain operations (e.g. rotate an image) can be performed asynchronously to avoid delaying interactive user input.Some examples of the practical usage of FIPS are also given, and the paper concludes with an assessment of how well FIPS has met its objectives and what improvements would be beneficial.FIPS is available on a commercial basis from Dynaflow Software Systems. For further information contact J Gras at the address indicated.
  • Item
    Micro-based CAD: A Production Tool for Manufacturing Engineering
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Goldman, Gary S.
  • Item
    Better Understanding through Formal Specification
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Duce, D. A.; Fielding, E. V. C.
    The Graphical Kernel System (GKS) is now registered as an ISO International Standard for computer graphics programming. One of the major innovations of the Standard is the bundled specification of aspects, a mechanism which gives the applications programmer the ability to tailor the appearance of a picture independently on each of the workstations on which it is displayed, using the capabilities of the workstations. GKS also incorporates the traditional method of individual specification of aspects in which each workstation does the best it can to represent global aspect values. In this paper a formal specification technique, the Vienna Development Method (VDM), is used to describe aspect specification. The GKS model of aspect specification is progressively constructed from simpler models. Properties of these simpler models are formulated and the specifications are proved to conform to these. The properties are then traced through the more complex models. The paper demonstrates the applicability of formal specification to the design of graphics software and the ability of formal techniques to catalyse the deeper understanding of designs.
  • Item
    GKS Programming in a PHIGS Environment
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Arnold, David B.; Hall, Gillian; Reynolds, Graham J.
    GKS is an international standard for the functional interface to 2D graphics, whilst PHIGS is currently an ISO work item for 2D and 3D graphics. In addition, PHIGS allows improved control over structuring graphics data in the system. With a new work item, the upwards compatability from GKS to PHIGS is being called into question. This paper is an attempt to give direction to these discussions by listing the implications of introducing a software layer between a GKS application program and a PHIGS environment on which this application is to be run. It is intended to highlight differences between the systems and to answer questions such as, "How compatible?", "Is it possible?", "How much does the software layer have to do?", etc.
  • Item
    Generating High Quality Pictures by Ray-Tracing
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Bouville, C.; Brusq, R.; Dubois, J.L.; Marchal, I.
    Ray-casting techniques provide a very general framework in which many problems can be solved in a much easier way than with conventional methods. This is particularly true for the illumination model when a high level of realism is required. Another interesting feature of ray-casting is its ability to display a wide class of algebraic surfaces with a minimum of approximation. Both aspects are developed in this paper where a full lighting model, based on a theoretical approach, is presented. Then, an algorithm for the display of surfaces of revolution is described.Computation time is the major drawback of ray-tracing. Special purpose parallel processors seem to offer a good price/performance ratio compared to the use of supercomputers.
  • Item
    Arbitrary Area Filling in a Fast Procedure
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Ying, Dao-Ning; Feng, Xing
    A representation for area filling is described which allows shading of an area that may have both straight lines and circular arc edges and include holes within its boundaries. For efficiency an elimination algorithm which has a waiting line list and a currently active line list is adopted. For calculating intersections, a more time saving method is used. The algorithm and some practical examples are discussed. The main features of the algorithm are execution with high speed and less storage requirement. The program is written both in BASIC and FORTRAN 77 and could be executed on a microcomputer such as APPLE II, IBM-P/C etc. The sample outputs shown in this paper are generated by the APPLE II with high efficiency.
  • Item
    A Survey of Electronics R and D in the USA
    (Blackwell Publishing Ltd and the Eurographics Association, 1985) Prince, M.D.