The road to graphics standards

There has been a concerted effort over the last few years to define international standards for computer graphics. This paper outlines the history leading up to GKS being lodged with the International Standards Organization as a Draft Proposal for an international standard.     

GKS-the standard for computer graphics

GKS is about to be ratified as the first international standard for computer graphics. It will provide a unique base on top of which portable graphical applications software can be built. This paper traces the history of GKS and describes its main concepts.     

Graphic design for computer graphics

Because computer graphics systems are capable of sophisticated displays of typography, symbols, color, spatial organization, and temporal sequencing, it is appropriate to seek principles for designing effective communication from the discipline of graphic design whose expertise lies in programming visible language. Examples of the author's work are cited to demonstrate how graphic design can improve three different types of computer graphics.     

GKS-9x: Some Implementation Considerations

The Graphical Kernel System (GKS) was published as an ISO standard for computer graphics programming in August 1985. GKS is now undergoing revision in ISO/IEC and at the time of writing the text of the Draft International Standard of GKS-9x was being finalized. This paper presents a way in which a key part of the new functionality in GKS-9x, namely namesets and selection criteria, can be implemented effectively.     

Relationship between scene complexity and perceptual performance for computer graphics simulations

An important goal for the design of visual displays is to determine how much realism or scene complexity to include in a computer simulation to reach a given level of performance. This is an important task since the present trend in computer graphics is to include the highest level of realism or scene complexity possible in a simulation. However, it may not be necessary to always include the highest level of realism or complexity to reach an acceptable level of performance. In fact, needless degrees of realism, and thus computational resources, may be wasted in the quest for ‘photographic’ realism. To study the relationship between scene complexity and human performance, three different simulations of scene complexity were modeled for a final approach task. The subject's task were to estimate two aspects of situation awareness, perceived altitude and aimpoint, during a simulated final approach at nine unique distances to threshold. The three levels of scene complexity included a homogeneous Lambertian shaded flat surface, farmlands, and farmlands with hills. The results indicated that increasing the level of scene complexity lead to better performance in judging both altitude and aimpoint during the simulated final approach. The relationship between scene complexity and perceptual performance for computer graphics simulations are discussed.     

Chemical ideograms and molecular computer graphics

Molecular computer graphics (MCG) has become the indispensable complement of experimental chemical and biological tools and, in a way, will shape the evolution of these fields. This accelerated and popularized evolution takes root in the visual, even scenic, grasping of fundamental chemical concepts, perceived as veritable ideograms, which condense a vast amount of information with a few two- or threedimensional graphic symbols. With MCG one can carry out real computerized syntheses of chemical images. MCG is also an ideal tool through which to visualize the changes of a system as a function of time. This review article describes the potentials and advantages of structural MCG for visualizing the basic steps of important modelization concepts, particularly for handling on-line structures in information networks and in computer-assisted drug design (CADD) applications.     

GKS Programming in a PHIGS Environment

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.     

Discriminating between photorealistic computer graphics and natural images using fractal geometry

Rendering technology in computer graphics (CG) is now capable of producing highly photorealistic images,giving rise to the problem of how to identify CG images from natural images. Some methods were proposed to solve this problem. In this paper,we give a novel method from a new point of view of image perception. Although the photorealistic CG images are very similar to natural images,they are surrealistic and smoother than natural images,thus leading to the difference in perception. A part of features are derived from fractal dimension to capture the difference in color perception between CG images and natural images,and several generalized dimensions are used as the rest features to capture difference in coarseness. The effect of these features is verified by experiments. The average accuracy is over 91.2%.     

A survey of point-based techniques in computer graphics

In recent years point-based geometry has gained increasing attention as an alternative surface representation, both for efficient rendering and for flexible geometry processing of highly complex 3D-models. Point-sampled objects do neither have to store nor to maintain globally consistent topological information. Therefore they are more flexible compared to triangle meshes when it comes to handling highly complex or dynamically changing shapes. In this paper, we make an attempt to give an overview of the various point-based methods that have been proposed over the last years. In particular we review and evaluate different shape representations, geometric algorithms, and rendering methods, which use points as a universal graphics primitive.     

An introductory computer graphics laboratory

Methods are described for teaching students how to write computer programs to perform basic graphics operations. The elementary operations of scaling, translation, reflection, shear, rotation and clipping are presented. Graphics 1000, a Hewlett-Packard graphics software product is the software used. This product imbeds subroutine calls in a FORTRAN program to execute the graphics functions. The laboratory sessions are divided into modules. Module I uses interactive programs to demonstrate graphics operations. Module II introduces Graphics 1000 commands. Module III uses interactive programs to demonstrate XY plotting with as many as four graphs per plot. Module IV uses interactive programs to demonstrate rotation of objects with hidden line removal. Students are assigned tasks ranging from drawing a section of an I beam through rotation of a three-dimensional object. Computer programs used for the demonstrations are available for the students to examine in order to learn how they work.     

A component-oriented framework for experimental computer graphics

This paper provides a report about a framework that uses a variety of standards. Readers interested in 3D computer graphics or component-oriented technology in C++ will find a report about the integration of various standards by relying on yet another standard for component-oriented software engineering. The highly successful Java standard called Open Services Gateway initiative (OSGi) is employed in a C++ implementation called Open Service Platform.The application of this standard, which is primarily focused on network-centric software and embedded systems, in the field of real-time 3D computer graphics, provides novel insights into the usability of the OSGi standard.     

Ergonomic aspects of installing graphics CAD systems

This paper discribes the practical aspects of designing a sound working environment for a CAD system. Installation requirements with reference to both the designer and the computer suite are examined. Alternative designs for work stations were proposed and evaluated. The actual layout of the COMPASS(computer orientated management, production and scheduling system) suite is described. The needs of the designer working within a CAD system are considered and some general observations and conclusions concerning the installation of CAD systems are made.     

The mathematics of computer graphics

Until relatively recently, researchers in computer graphics paid scant attention to the numerics of their computations. Computation was used as a simple tool to evaluate algorithms or transform data into some appropriate pictoral representation. Thus standard computer graphics texts have little to say about numerical methods, just as earlier numerical analysis textbooks had little to say about computer graphics. This is now changing, for the important reasons outlined in this paper.     

Segments on bit-mapped graphics displays

The problems associated with using picture segments in interactive applications on workstations with bit-mapped displays are discussed. A method for displaying and updating segments is introduced.     

Are autostereograms useful for computer graphics and scientific visualization

Autostereograms are images that can be observed as “flat” 2D pictures or as a display of 3D objects without any extra apparatus. More than one million copies of books on this subject have been sold recently, but are autostereograms useful for computer graphics and scientific visualization? This short note provides some assistance for easily designing still and animated autostereograms, and tries to encourage reader involvement in finding new scientific applications.     

My personal history in the early explorations of computer graphics

Gary Demos discovered computer graphics while hearing a computer-generated film presentation at CalTech in 1970 by John Whitney Sr. Gary then began working under the direction of Ivan Sutherland in Utah to develop early computer graphics hardware and software. In 1974 Gary and John Whitney Jr. started the “Motion Picture Project” at Information International to produce computer generated simulated scenes for movies (Futureworld, Looker, and Tron) and commercials. These early computer-generated visuals were quite challenging given the level of software and hardware technology available in the 1970’s. In 1981 Gary and John left Information International to form Digital Productions, where they produced effects for the movies Last Starfighter and “2010”, which were both released in 1984. Digital Productions used the Cray XMP computer, together with the Digital Film Printer that they had developed at Information International. Following a hostile takeover by Omibus of Digital Productions in 1986, Whitney/Demos Productions was formed, using a Thinking Machine parallel computer. This paper describes the technical challenges and achievements of this early visual computing.     

The Formal Specification of Level la of GKS

In this paper the formal specification of a part of level la of GKS is given in the algebraic specification language OBJ. It shows that it is possible to produce a formal specification of a substantial part of GKS which is of manageable size and complexity specifying the appropriate level of abstraction of the system and using a suitable formal technique.     

Applications of Euclidean constructions to computer graphics

This paper presents an interactive graphics system called L.E.G.O. The purpose of L.E.G.O. is to model two- and three-dimensional objects using Euclidean geometry constructions. L.E.G.O. has a layered structure which makes it convenient to use, both for the experienced programmer and the novice. The programs may be written in a compiled language (C), written interactively in an interpreted language (LISP) or developed using a graphical interface in a multiple-window environment. Applications of L.E.G.O. include computer-assisted instruction of geometry and computer graphics, geometric modeling, and kinematic analysis. The use of imperative constructions and the powerful interface based on the idea of graphical programming are the most distinctive features of the system.