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1990 Symposium on Interactive 3D graphics, I3D 1990

作者： Phillips, Cary B. Zhao, Jianmin Badler, Norman I. Computer Graphics Research Laboratory Department of Computer and Information Science University of Pennsylvania PhiladelphiaPA19104-0389 United States

ISBN: (纸本)0897913515

In this paper, we describe an interactive system for positioning articulated figures which uses a 3D direct manipulation technique to provide input to an inverse kinematics algorithm running in real time. The system allows the user to manipulate highly articulated figures, such as human figure models, by interactively dragging 3D "reach goals." The user may also define multiple "reach constraints" which are enforced during the manipulation. The 3D direct manipulation interface provides a good mechanism for control of the inverse kinematics algorithm and helps it to overcome problems with redundancies and singularities which occur with figures of many degrees of freedom. We use an adaptive technique for evaluating the constraints which allows us to ensure that only a certain user-controllable amount of time will be consumed by the inverse kinematics algorithm at each iteration of the manipulation process. This technique is also sensitive to the time it takes to redraw the screen, so it prevents the frame display rate of the direct manipulation from become too slow for interactive control, © 1990 ACM.

关键词： Degrees of freedom (mechanics)

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Symmetric algorithms for curves and surfaces

Symmetric algorithms for curves and surfaces

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Curves and Surfaces in computer Vision and graphics 1990

作者： Seidel, Hans-Peter Computer Graphics Laboratory Department of Computer Science University of Waterloo WaterlooONN2L 3G1 Canada

Using the concept of symmetric algorithms, we construct a new patch representation for bivariate polynomials: the B-patch. B-patches share many properties with B-spline segments: They are characterized by their control points and by a 3-parameter family of knots. If the knots in each family coincide, we obtain the Bezier representation of a bivariate polynomial over a triangle. Therefore B-patches are a generalization of Bezier patches. B-patches have a de Boor-like evaluation algorithm, and, as in the case of B-spline curves, the control points of a B-patch can be expressed by simpy inserting a sequence of knots into the corresponding polax form. B-patches can be joined smoothly and they have an algorithm for knot insertion that is completely similar to Boehm's algorithm for curves. © 1990 SPIE. All rights reserved.

关键词： Curve fitting

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Heuristics for ray tracing using space subdivision

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The Visual computer 1990年第3期6卷 153-166页

作者： MacDonald, J.David Booth, Kellogg S. Visual Edge Software Ltd. Montreal Canada Computer Graphics Laboratory Department of Computer Science University of Waterloo Waterloo N2L 3G1 Ontario Canada

Ray tracing requires testing of many rays to determine intersections with objects. A way of reducing the computation is to organize objects into hierarchical data structures. We examine two heuristics for space subdivisions using bintrees, one based on the intuition that surface area is a good estimate of intersection probability, one based on the fact that the optimal splitting plane lies between the spatial median and the object median planes of a volume. Traversal algorithms using cross links between nodes are presented as generalizations of ropes in octrees. Simulations of the surface area heuristic and the cross link scheme are presented. These results generalize to other hierarchical data structures. © 1990 Springer-Verlag.

关键词： Octree Ray tracing Space subdivision Splitting plane Surface area

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Towards image realism with interactive update rates in complex virtual building environments1 90

Towards image realism with interactive update rates in compl...

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1990 Symposium on Interactive 3D graphics, I3D 1990

作者： Airey, John M. Rohlf, John H. Brooks, Frederick P. Department of Computer Science Sitterson Hall University of North Carolina Chapel HillNC27599-3175 United States Silicon Graphics Computer Systems Mountain ViewCA94039-7311 United States

ISBN: (纸本)0897913515

Two strategies, pre-computation before display and adaptive refinement during display, are used to combine interactivity with high image quality in a virtual building simulation. Pre-computation is used in two ways. The hidden-surface problem is partially solved by automatically pre-computing potentially visible sets of the model for sets of related viewpoints. Rendering only the potentially visible subset associated with the current viewpoint, rather than the entire model, produces significant speedups on real building models. Solutions for the radiosity lighting model are precomputed for up to twenty different sets of lights. Linear combinations of these solutions can be manipulated in real time. We use adaptive refinement to trade image realism for interactivity as the situation requires. When the user is stationary we replace a coarse model using few polygons with a more detailed model. Image-level linear interpolation smooths the transition between differing levels of image realism. © 1990 ACM.

关键词： Interactive computer graphics

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A parallel-hierarchical method for grouping line segments into contours

A parallel-hierarchical method for grouping line segments in...

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Applications of Digital Image Processing XII 1989

作者： Khan, Gul N. Gillies, Duncan F. Department of Computing Computer Vision and Graphics Group Imperial College of Science Technology and Medicine 180 Queen's Gate LondonSW7 2BZ United Kingdom

A highly parallel technique for linking line segments into curved contours or boundaries has been developed. This bottom-up organization of the line segments utilizes information in the line data itself and perceptual organization rules which are domain independent. The line segments can be detected on a local basis and are amenable to parallel computation. 1 A line pyramid structure is employed where the two bottom levels of the pyramid hold the line segments extracted from pre-defined image windows (e.g. 4x4 and 8∗8). The pyramid is based on a 4x4 overlapping neighbourhood and each processing element is connected to four parents and sixteen children. Starting from the lower level, each processing element performs grouping on the line data supplied by all of its children but it only keeps the grouped line segments supplied by its central 2x2 children for passing on to the parents. The main grouping criteria employed to achieve the aggregation of line segments are proximity, Marr's theta-aggregation,^ curvilinearity, continuity and similarity in line contrast. By the time the root processor of the pyramid is reached, all the groups of line segments are formed and they are then replaced by contours. The main features of the method are its parallel implementation on a pyramid architecture computer and use of domain independent perceptual grouping principles. © 1990 SPIE. All rights reserved.

关键词： computer architecture

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Real-time robot motion planning using rasterizing computer graphics hardware 90

Real-time robot motion planning using rasterizing computer g...

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Proceedings of the 17th annual conference on computer graphics and interactive techniques

作者： Jed Lengyel Mark Reichert Bruce R. Donald Donald P. Greenberg Graduate Student Program of Computer Graphics Cornell University Ithaca N.Y. Assistant Professor and Director Computer Science Robotics Laboratory Department of Computer Science 4130 Upson HalI Cornell University Ithaca N.Y. Director Program of Computer Graphics Jacob Gould Shurman Professor of Computer Graphics Cornell University Ithaca N.Y.

ISBN: (纸本)9780897913447

We present a real-time robot motion planner that is fast and complete to a resolution. The technique is guaranteed to find a path if one exists at the resolution, and all paths returned are safe. The planner can handle any polyhedral geometry of robot and obstacles, including disjoint and highly concave unions of *** planner uses standard graphics hardware to rasterize configuration space obstacles into a series of bitmap slices, and then uses dynamic programming to create a navigation function (a discrete vector-valued function) and to calculate paths in this rasterized space. The motion paths which the planner produces are minimal with respect to an L1 (Manhattan) distance metric that includes rotation as well as *** examples are shown illustrating the competence of the planner at generating planar rotational and translational plans for complex two and three dimensional robots. Dynamic motion sequences, including complicated and non-obvious backtracking solutions, can be executed in real time.

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Report on AUSGRAPH '90, the 1990 Australian graphics Conference Melbourne, 10–14 September 1990

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computer graphics Forum 1990年第5期9卷 389-389页

作者： Maeder, Anthony Computer Graphics and Image Processing Research Laboratory Department of Computer Science Monash University Clayton 3168 Australia

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A programmer's interface: a visually enhanced and animated programming environment

A programmer's interface: a visually enhanced and animated p...

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Annual Hawaii International Conference on System sciences (HICSS)

作者： R. Baecker J. Buchanan Dynamic Graphics Project Computer Systems Research Institute University of Toronto Toronto ONT Canada Department of Computer Science University of British Columbia Vancouver BC Canada

The authors describe LOGOmotion, a programming environment that is visually enhanced, animated, unobtrusive, extensible, and monomorphic. The programmer can obtain with ease visual and animated presentations of the execution of programs written in the LOGO language. The programmer can also define new methods of program presentation by writing visualization procedures in LOGO without altering the original program code. Methods may include classical debugging tools such as traces, as well as more modern visualization aids such as the animation of program behavior. The design goals and fundamental principles of the system are discussed. Illustrations of its use and implementation are presented.< >

关键词： Animation Programming environments Visualization Displays Programming profession computer graphics Debugging Motion pictures computer science Writing

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CAFE-the MIT computer aided fabrication environment

CAFE-the MIT computer aided fabrication environment

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IEEE/CHMT(CPMT) International Electronics Manufacturing Technology Symposium

作者： M.B. McIlrath D.E. Troxel D.S. Boning M.L. Heytens P. Penfield R. Jayavant Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA USA Graphics Technology Division Hewlett Packard Company Fort Collins CO USA

The computer-aided fabrication environment (CAFE) is a software system being developed at MIT for use in the manufacture of integrated circuits. CAFE is intended to be used in all phases of process design, development, planning, and manufacturing of integrated-circuit wafers. The CAFE architectural framework supports a wide variety of software modules, including both development tools and online applications. The key components of the CAFE architecture are the data model and database schema, the process flow and wafer representations, the user interface, and the application programming and database interfaces. All CAFE application modules store and retrieve persistent data through a common database interface layer. Interface wrappers provide seamless, transparent integration of external tools and packages which have their own internal data formats.< >

关键词： Fabrication Application software Databases computer aided manufacturing Software systems Integrated circuit manufacture computer integrated manufacturing Process design Process planning Manufacturing processes

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THE COMMAND SUPPORT AT-SEA EXPERIMENT

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 25-36页

作者： BUSCHER, DJ SUNDAY, DM David J. Buscher:is an electrical engineer on the Principal Professional Staff of the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He earned his BS degree in electrical engineering from Villanova University in 1967 an MSEE degree from the University of Maryland in 1972 and an MS degree in technical management from The Johns Hopkins University in 1985. He was the lead engineer on the Command Support At-Sea Experiment Project. He started his career in 1967 with the U.S. Army Harry Diamond Laboratory working on computer and communications projects. During this time he worked in Vietnam with the United States Army Vietnam Science Advisor Office. Since joining JHU/APL in 1978 he has worked on a variety of projects associated with computer graphics hospital patient information systems computer networks autonomous underwater vehicles and satellite communications. He is currently assistant group supervisor of the Computer Systems Group. Daniel M. Sunday:is a mathematician on the Principal Professional Staff of the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He earned his Ph.D. in mathematics from the University of Minnesota in 1971 and did postdoctoral research on neural networks at the University of California at Berkeley. Since joining JHU/APL in 1980 Dr. Sunday has worked as a designer and developer of software systems with emphasis on medical imaging interactive graphics natural language interfaces and software standards. He was the network designer for the Headquarters Integrated Office System (HIOS) Network for the Army at the Pentagon. He is currently the lead software engineer on the Command Support At-Sea Experiment Project.

The Command Support At-Sea Experiment (CS@SE) provides experimental advanced graphics display systems consisting of large screen color displays and operator console color displays in the combat information center (CIC) of an Aegis cruiser and in the tactical flag command center (TFCC) of an aircraft carrier. CS@SE systems are designed to prototype potential command support capabilities in an at-sea environment to validate and refine requirements for planned production system upgrades. These systems use sophisticated color graphics techniques to provide real-time tactical displays that improve the availability of information to an operator by reducing clutter through the use of color, area fill, transparen overlays and intensity coding of track symbols. Interfaces wen developed with the Aegis Display System (ADS), Shipboarc Gridlock System with Auto-correlation (SGS/AC), Flag Dats Display System (FDDS) and Tomahawk Engagement Planning and Exercise Evaluation System (TEPEE) that provided the data for the presentation of a tactical display. Display elements included both real-time and over-the-horizon (OTH) surface track data, velocity leaders, tags, uncertainty ellipses, and history trails. The display also included filled land masses, country boundaries, commercial airways, cities, graphics overlays (i.e., operational areas), weapon system missile performance contours, and engagement plans. This paper describes the experiment, its installation and integration into the shipboard environments of an Aegis cruiser (USS Leyte Gulf ) and an aircraft carrier (USS America , its usage by the ships companies and embarked staffs, and the experiment result! and findings. Key conclusions of the experiment are: 1 Advanced graphics color displays can significantly enhance the ability of the warfighter to assimilate a complex tactical display. 2 Both ships reported a requirement for a correlated OTH and real-time track display with the ability to clearly differentiate the two types

关键词： computer graphics

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