EG1986

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    A Multiprocessor Architecture For High-Quality Interactive Displays
    (The Eurographics Association, 1986) Sutherland, Robert J.; A.A.G. Requicha
    A multiprocessor array coupled to a deep framebuffer is proposed as the basis for an interactive user environment of high quality. Several aspects of such an architecture are considered, improvements on previous approaches are suggested, and two designs of high-performance displays based on standard LSI components are described.
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    Multi-Dimensional Graphics: Algorithms & Applications
    (The Eurographics Association, 1986) Inselberg, Alfred; A.A.G. Requicha
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    An Introduction to the Graphics Systems Processor
    (The Eurographics Association, 1986) Short, Graham; A.A.G. Requicha
    This paper describes the system applications of the Graphics System Processor (GSP) produced by Texas Instruments Inc. The paper discusses the general-purpose capabilities of the GSP which make it a flexible processor to use. It then goes on to show how the graphics-specific parts of the GSP make it a powerful tool, ideally suited to graphics applications. Finally the paper discusses some of the programmable hardware functions of the GSP which make it easy to design into any graphics system.
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    A Portable Graphical Display System For The Partially Sighted
    (The Eurographics Association, 1986) DUNLOP, G.R.; B.Sc.,; B.E.(Hons),; Ph.D.,; M.I.E.E.,; C.Elec.Eng.,; A.A.G. Requicha
    A portable reading aid based on a graphical display system has been developed for partially sighted persons. This graphical display system incorporates dual microprocessor control of a flat panel AC plasma display and a solid state fibre optics camera. The unique camera uses coherent fibre optics for image dissection so that a synthetic viewing aperture is generated from a single linear imaging device. The lensless camera utilises proximity focusing and switchable electronic magnification settings from 4 to 64. The graphical display produces neon orange images which are refreshed at almost 100 Hz to give bright flicker free images which are suitable for viewing either directly or with only the peripheral vision available to many partially sighted people.
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    A Multiple Application Graphics Integrated Circuit - MAGIC
    (The Eurographics Association, 1986) Agate, M.; Finch, H.R.; Garel, A.A.; Grimsdale, R.L.; Simmonds, A.C.; Lister, P. F.; A.A.G. Requicha
    MAGIC is a geometry processor which Corms a part of a graphics system based on parallel processing. The number of MAGIC processors required is dictated by the desired system performance. Each unit is capable of controlling the transformation of points and edges from the co-ordinate system of the world model into screen co-ordinates, and performing the associated clipping operations. The proposed VLSI implementation of these transformations is intended to be sufficiently flexible for additional operations such as texture mapping and ray tracing to be supported.
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    A consistent algorithm to fill triangles and triangular patches
    (The Eurographics Association, 1986) Overveld, C.W.A.M. van; Lierop, M.L.P van; A.A.G. Requicha
    In this paper an algorithm is described for filling triangles in 3D. Since this algorithm uses integer arithmetic only, it is not hampered by inconsistencies that normally arise due to finite machine precision. Moreover, the same algorithm is used for both curved and flat triangular patches.
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    A Visualisation Tool for (Landscape) Architects
    (The Eurographics Association, 1986) Lankhorst, Mrs. J. Roos - Klein; A.A.G. Requicha
    In a small and crowded country such as the Netherlands both the government and the individual people are very concerned with what is happening in their environment. Apart from the ecological impacts, the visual effects of new developments are often a very important issue. In this respect a realistic visualisation of future developments can be very useful. Described here is the product of the first stage of a research programme aimed at providing visualistion aids for landcape architects and building designers. Besides showing future developments to the people involved, this tool should enable the building designer to evaluate the aesthetics of a design with respect to the surroundings. Moreover it should enable the landscape architect to "reshape" the landscape by adding, removing and editing artifacts and natural elements on the the graphics screen.
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    A Statistical Method For Adaptive Stochastic Sampling
    (The Eurographics Association, 1986) Purgathofer, Werner; A.A.G. Requicha
    Stochastic sampling is a good alternative to pure oversampling in terms of image quality. A method for adaptively controlling the number of required samples to the complexity of the picture is presented. The quality of the obtained picture can be controlled by two well-understandable parameters, these parameters define an error interval sire and the probability that a pixel lies within it. The usefulness of the method is described by applying it to distributed ray-tracing.
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    A Quad-Tree Algorithm for Displaying a 2-Dimensional Slice of an N-Dimensional Weighted Voronoi Tessellation
    (The Eurographics Association, 1986) Angell, Ian O.; Moore, Richard E.M.; A.A.G. Requicha
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    Towards a Formal Specification of the GKS Output Primitives
    (The Eurographics Association, 1986) Duce, D. A.; Fielding, E. V. C.; A.A.G. Requicha
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    Methods for Cross-Sectional Design of B-Spline Surfaces
    (The Eurographics Association, 1986) Woodward, Charles D.; A.A.G. Requicha
    The complexity of free-form surface construction and interaction can often be reduced with methods of crosssectional design. A number of such methods, includin sweeps, skinning and surface interpolation are described in this paper for the B-spline surfaces. The methods are demonstrated with examples using the CUBES subroutine package.
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    An Adaptive Graphics Interface for Effective Visual Representation
    (The Eurographics Association, 1986) Holynski, Marek; Garneau, Robert; Lewis, Elaine; A.A.G. Requicha
    This paper presents a progression of experimental work aimed at incorporating principles of graphic presentation and preferences of users into a computer graphics system. These standard-s for effective visual representation of data are based on empirically developed criteria. Several different approaches for obtaining these criteria from picture attributes are described. First, relevant attributes are verified using a series of pictures created with a menu-driven program. Then representation criteria are developed by an automatic rule acquisition program in the form of condition-action rules. These rules can be utilized by an adaptive graphics system that can generate, change and refine images interactively. Practical applications are suggested.
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    An Advanced Display System With Natural Interactivity
    (The Eurographics Association, 1986) Kankaanp, Arto; A.A.G. Requicha
    This paper describes an experimental display system that allows easy interaction with the graphics display. The user uses a pen-like device to draw directly on the display surface. The system is based on an electroluminescent flat panel with a resistive touch-sensitive surface. A pen with a conductive tip is used for direct drawing. For evaluation the display system is connected to a powerful microcomputer having a true bit-mapped graphics capability. The prototype software consists of a word processing program that includes integrated line graphics drawing capability. Text correction and formatting is done directly on the display using standard proof correction marks. Graphics drawing is done by sketching a figure on the screen with the pen and correcting it by software. The system is also evaluated using the Keystroke-Level Model by CARD et. al. [1] for accomplishing the basic editing tasks with a word processing application.
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    Mappings Between Product Data Definitions
    (The Eurographics Association, 1986) Richter, Dieter; A.A.G. Requicha
    It can be observed that existing product data interfaces are constructed by a pragmatic manner. It is not seen any theoretical approach neither for describing nor for evaluating models. In this paper an algebraic approach based on heterogeneous algebras is presented.
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    A Version Management System for Design Environments
    (The Eurographics Association, 1986) Heine, Thomas Riedel-; Köhler, Dagmar; A.A.G. Requicha
    Design environments for CAD/CAM require new techniques of version management. This work presents a concept of a largely data modelindependent version manager thus allowing easy integration into any existing database system. An implementation proposal of a version manager based on a relational database system is given.
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    CSI: A Processor for Image Synthesis
    (The Eurographics Association, 1986) Charot, Francois; Rousee, Frank; A.A.G. Requicha
    A high performance processor convenient for image synthesis is presented. The processor named CSI is programmable and can support either image synthesis by polygons or by ray casting. CSI consists of two 32- bits floating point processors as well as control facilities to support complex algorithm. CSI will be able to compute at a rate of 20 MFLOPS. Several processors can be arranged in a pipeline mode to perform the computation for image synthesis by polygons, or viewed as a set of co-processors connected to a bus and implementing efficiently image synthesis by ray casting algorithms.
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    Digital Synthesis Of Calligraphic Script
    (The Eurographics Association, 1986) Dooijes, E.H.; A.A.G. Requicha
    We discuss some of the problems associated with the generation of publication quality, quasi-calligraphic script from keyboard input. Our ultimate goal is the construction of a system for the production of Arabic texts, to be implemented on a microcomputer.
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    The Integrated Display Controller (IDC) for VLSI-Design Workstations
    (The Eurographics Association, 1986) Strk, Jrgen; A.A.G. Requicha
    A display controller to accelerate the updating of the frame buffer in raster displays is presented. The advantage of a frame buffer system is the ability to display pictures of any complexity, flicker free. The disadvantage is the great amount of pixel data, which must be updated, when the picture is changed. The Integrated Display Controller (IDC) described in this paper gets its name from the fact, that both a pixel plane and a processor are integrated on a single chip. An internal logical unit, a shifter and special memory are provided to process complete rows and columns of pixels, or some part of them in parallel All operations are performed in one bus cycle, which means that all the pixels addressed in the row or column are modified at the same time. Due to the special organization of the IDC, time consuming operations like block transfer or scrolling can be done significantly faster than in conventional systems. An experimental IDC with a lower screen resolution is developed to demonstrate the feasibility of the design. It is intended for use in VLSI-design workstations, where a great quantity of data has to be manipulated.
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    The Integration of Particle and Polygon Rendering using an A-buffer Algorithm
    (The Eurographics Association, 1986) N.Magnenat-Thalmann,; D.Thalmann,; S.Beland,; A.A.G. Requicha
    A particle system, as defined by Reeves, is a collection of particles that together represent a fuzzy object. Over a period of time, particles in the system are born, move, change and die. We have introduced interactive control of procedural models into our extensible director-oriented animation system MIRANIM. With this approach, a user may define his/her own evolution laws in particle systems. Systems may be initialized by interactive commands and are then updated by animation blocks, and the laws may return any state variables. Unlike Reeves' work, particle systems may intersect with other surface-based modeling primitives. Our rendering method is based on a scanline A-buffer algorithm, which is an extension of the processing of translucent polygons. This approach proved to be particularly useful for modelling objects destroyed by a fire with the presence of a wind.
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    Linked Management Graphics For Production Control
    (The Eurographics Association, 1986) Woodgate, H. Sam; A.A.G. Requicha
    This paper describes the use of Linked Graphical Displays as a means of extending the information transfer capability of Management Graphics Systems in the context of Engineering Manufacturing. As the pace and complexity of manufacturing increases, management need faster and better methods of absorbing the information contained in the large Databases used to control production. In the system described a number of different graphical displays are created from the same large Database and accessed via a "Choice Processor" to give multiple views on the situation represented by that data. The simple effectiveness of computer produced graphics as a man/machine communication media is retained but the multiple access facility enables more complex issues to be revealed and cross checked by sequentially viewing and comparing different interpretation of Data. Examples of the Charting Techniques employed are described together with an explanation of how they are created and used.