Low cost computer graphics in engineering education

The Apple II is a personal computer which provides 6 color, raster graphics via a 280 h × 192 v frame buffer. A user-programmable MOS Technology 6502 CPU addresses 48 K bytes of RAM, 12 K of ROM. and 4 K of memory-mapped I/O. This system has been evaluated in a variety of applications for which one normally assumes higher resolution, higher cost graphics devices are needed.Examples were drawn from computer aided design, color microfilm previewing, cartography, and aircraft synthesis. The results were encouraging: low resolution raster scan graphics is surprisingly effective for a wide range of applications. As a result, a computer graphics laboratory, with a cluster of 10 Apples as its nucleus, was formed and has been functioning successfully for 4 terms.     

A persistent graphics facility for the ICL PERQ

The facilities of the PS-algol programming language are described in this paper to show how they may be used to provide an integrated programming support environment. The persistent store mechanism and the secure transaction facilities provide the basic environment in which an integrated system may be implemented. In particular the paper makes use of the data type picture of PS-algol to show how such an environment may be built for a graphics system ideal for use with a medium range computer workstation. An implementation of a picture editor on the ICL PERQ workstation is described to show the utility of the system.     

The evolution of a graphics system for linked computers

The development of a comprehensive two-dimensional graphics package for an ICL 4130 with a high-speed data link to a DEC PDP-7 with Type 340 refreshed C.R.T. display and light pen is traced from its origin as a package of ALGOL procedures for graphical output. The design criteria imposed by the requirements for light-pen tracking and identification of picture parts are described, and decisions which affected the subsequent development of the sysetm are identified and commented upon. The various types of display file editing which may be performed are described, and a facility mentioned for saving display files on the backing store of the PDP-7. The idea of a ‘fixed-function satellite’ is introduced and its potential usefulness in other operating environments discussed.     

Abstraction paradigms for computer graphics

In computer graphics we use techniques from different areas of mathematics. Mathematical models are used to simulate real-world objects, as well as natural phenomena. In order to understand these models and pose relevant problems in each particular field of this area, it is important to create levels of abstraction. These levels encapsulate common properties of the different models and allow us to have a global, conceptual view of the methods and techniques in each field. In this paper we study a paradigm for creating abstraction levels that can also be used to characterize more general problems in computational applied mathematics. We apply this paradigm to different areas of computer graphics: modeling, animation, illumination, color theory, image processing and human-computer interface.     

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.     

G-plot: graphics in the geological computer

G-PLOT is a package of programs for graphic display of data. It has been designed as an integral part of the G-EXEC data-handling system, and adopts the principles of G-EXEC: it is generalized with respect to data, it is structured and modular, and it has a simple (near-English) user interface. In addition, a number of standards have been defined to allow the greatest possible flexibility of usage of the programs, as well as to provide a consistent and powerful set of modules for the applications programmer. The two most significant of these standards are the use of the ‘plot-frame’ concept and the definition of logical raster levels between the data and a ‘logical plotter’. By the use of these standards, it is possible not only to send generated plots to any available graphic device, but also to edit plots by selection and manipulation of logical ‘subframes’—units of plot data such as axes, titling, map frames, and grids. By the combination of G-PLOT facilities with planned enhancements to the G-EXEC system, it will be possible to generate sequences of plot frames from iterative simulation models, or from successively changing parameters (scaling or rotation for example) in normal application programs.     

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.     

A formalization for the specification and systematic generation of computer graphics systems

A formalization of graphical processes in computer graphics systems is presented in terms of functions and their system of axioms. The concept of the viewing pipeline is formalized as operation sequence which is a sequential composition of graphical elementary operations. The formalization includes two kinds of operation sequences which are used as the formal specifications of graphics systems and display devices. In order to generate a graphics system using a display device, we introduced the concept of functionality-preserving transformation of operation sequences in terms of various types of commutations among primitive operations. A type of transformation, which is called extraction, plays a central role in the generation algorithm.     

SYMMETRY: an interactive graphics computer program to teach symmetry recognition

SYMMETRY is a computer program that will draw two-dimensional motifs and patterns on the screen of a cathode-ray-tube (CRT) terminal. The program enables users to test for the presence of symmetry elements in these patterns by superimposing rotated, reflected, or glide-reflected patterns on the original.     

Low cost dual axis micro force sensor for robotic manipulations

A multi-dimensional force measurement device often plays an important role in micro robotic manipulations. Due to the high level required accuracy and physical dimensions of the sensors, they are normally fabricated through a series of MEMS process which makes the sensors not only prohibitive but also vulnerable to an excessive loading operation environment. In this article, an inexpensive force measurement using strain gauges is developed and tested. Combining a mechanical structure optimization and signal processing technique, the present work provides a fairly precise force measurement in sub-micron Newton scale. In addition, the developed concept is expanded to a dual axis force measurement which extends its application to the micro particle robotic manipulations.     

Concurrent processing for computer graphics

Three classes of concurrency are identified: data, functional and procedural. Within the constraints of human perception, interactive computer graphics requires real-time processing. Concurrent processing provides an alternative method of achieving real-time performance. Examples of graphic computations are presented which are applicable to each of these classes of concurrent processing.     

Homogeneous coordinates for computer graphics

Some mathematical aspects of homogeneous coordinates are presented. It is shown that the usual methods applied by workers in computer graphics are theoretically sound provided care is exercised in defining the range of the coordinate chart. The mechanics of the linear representation of transformations are explained in terms of commutative diagrams. Finally some familiar examples are discussed.     

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.     

Vector geometry for computer graphics

Computer graphics and modeling rely on mathematical operations on points and vectors. The author advocates using vector geometric analysis to simplify required derivations. He presents the basic language and methods of vector geometric analysis and characterizes the situations favoring vector geometric versus coordinate based analysis. A set of C++ classes is developed which includes methods and definitions of overloaded operators implementing nearly all of the low level operations and matrix construction algorithms presented in this article and its companion (J.R. Miller, see ibid., vol.19, no.4, 1999). Sample code using these tools to perform representative common operations is presented     

Modeling water for computer graphics

Water motion is a phenomenon the full complexity of which has yet to be realized in simulation. Although a good deal of work has been done in modeling water waves, there remain interesting behaviours which have not been captured in any existing model. The variety of phenomena realizable by water is extensive, including waves, foam, bubbles, and spray. The present work is motivated by the complexity and range of phenomena possible as well as by the frequency with which such phenomena are encountered. Water motion has been extensively studied from a physical perspective. A computational model should take advantage of past work in this area. Computer scientists have incorporated some physics into models of water; however, currently existing models are incomplete. This paper considers the strengths and shortcomings of previous attempts to model water. The work involves the development of an extension and refinement of an existing microscopic model of fluid, and a formalization of some of the results of using this model. Some results of the model have been compared with the predictions due to hydrodynamic theory. Other results have been presented in the context of the situation being simulated, and the discussion hinges on observations of the real situation rather than on theory. In brief, the model displays great potential for simulation of surface waves, spray, and interactions between solid objects and fluid. The experimental work is largely able to substantiate claims as to the accuracy of the model at simulating the underlying physics.     

Introducing low cost/high quality computer graphics in polish national television

Abstract

In October 1988 the authors were invited to lecture at the University of Warsaw. During the visit they also gave an advisory lecture to the Computer Centre of Polish National Television on strategies for low cost computer graphics. This article discusses the strategies presented during the lecture.

Several possible generic strategies are examined below, and although they are discussed in the context of the Polish Television, most of the discussion would be valid and appropriate for any large television company. Indeed, with the advent of the satellite and cable television, even western commercial television stations will be inclined to develop policies for the introduction of low‐cost computer graphics into their productions.     

Texture synthesis techniques for computer graphics

Five primary approaches to texture synthesis for computer graphics are surveyed: a syntactic approach, a statistical approach, a growth model approach, a computer drafting approach, and a stochastic modeling approach. Most of these methods, derived from texture analysis techniques or from mathematical models of texture, have a relatively low-level, cumbersome way to define, manipulate, or input textures. As an alternative, a high-level language approach is proposed. It provides easy-to-use coding mechanisms to define, synthesize, and manipulate textures. The high-level approach is introduced by means of the Texture Synthesis Language (TSL).