Graphic Display Devices Research Articles

User expectations for multibeam echo sounders backscatter strength data-looking back into the future

With the ability of multibeam echo sounders (MBES) to measure backscatter strength (BS) as a function of true angle of insonification across the seafloor, came a new recognition of the potential of backscatter measurements to remotely characterize the properties of the seafloor. Advances in transducer design, digital electronics, signal processing capabilities, navigation, and graphic display devices, have improved the resolution and particularly the dynamic range available to sonar and processing software manufacturers. Alongside these improvements the expectations of what the data can deliver has also grown. In this paper, we identify these user-expectations and explore how MBES backscatter is utilized by different communities involved in marine seabed research at present, and the aspirations that these communities have for the data in the future. The results presented here are based on a user survey conducted by the GeoHab (Marine Geological and Biological Habitat Mapping) association. This paper summarises the different processing procedures employed to extract useful information from MBES backscatter data and the various intentions for which the user community collect the data. We show how a range of backscatter output products are generated from the different processing procedures, and how these results are taken up by different scientific disciplines, and also identify common constraints in handling MBES BS data. Finally, we outline our expectations for the future of this unique and important data source for seafloor mapping and characterisation.

An efficient algorithm for the dot generation of arbitrary ellipses

AbstractThis paper presents an algorithm which provides a high‐speed dot representation of an ellipse on the raster‐scan graphic display device. In the usual graphic display, straight‐lines and circles are used as the graphic primitives. In the three‐dimensional graphics, a projection on the two‐dimensional plane is often employed where a circle is in general projected as an ellipse. When a curve with rapidly varying curvature is to be represented, the approximation can be effected by a fewer number of components if ellipses are used instead of circles. From such viewpoints, an efficient generation algorithm for the ellipse is required. The ellipse considered in this paper need not have the long or short axis parallel to the coordinate axis. The lengths of the long and the short axis are arbitrary, and the correct dot generation is observed for an extremely oblong ellipse. The location of each dot is determined so that the deviation from the ellipse is small. Sometimes the past method does not work due to the fact that the ellipse is a two‐valued function. By contrast, this paper contains a simple scheme to convert the ellipse into a single‐valued function. To improve the speed of the algorithm, only addition‐subtraction and conditional test are used in the internal loop determining the dot location.

Computer-based soil data management system (COSMAS)

Abstract Four programs were provided to COSMAS for the graphic representation of soil survey data. Graphic representation as a map or graph is necessary for understanding and interpreting soil survey data and for publishing the results. In the system, site and polygon data, raw or processed, are automatically converted into a map or a diagram on a graphic display device and X-Y plotter through these programs. Program “PLOT” transcribes the required data onto their observation sites to produce a site-attribute plotting map. Program “CONTOUR” prepares an isoline map for a given attribute. Program “TRANSECT” gives a transect-attribute diagram to demonstrate the relationship between a given attribute and the topography along the transect set by the user. Program “MAP” controls the management and output of the polygon data which are stored in the Cartographic File, and whole or screened areas of a thematic map can be reproduced with the program. These programs feature interactive query and response on a graphi...

A dedicated graphic computer: is it time to specialize?

Mini- and micro-computers have generated a proliferation of general purpose computers. Graphic display devices are also available in a great number and variety. The two elements have been used together, but never fully integrated. This paper postulates that the time has come to stop generalizing, and to use special purpose computers which combine elements of the general purpose computer and the graphic display generator, and which are specifically designed to support computer graphics. The problems anticipated with this specialized machine and with the architecture for a graphics computer are developed and discussed.

Curve analysis of small-angle scattering by triaxial body models using a graphic display device

An interactive program using a graphic display device for the analysis of small-angle scattering has been developed. It includes the curve fitting of experimental data to theoretical results calculated through a triaxial body approximation.

Interactive search for the global maximum of a function of many variables

This paper discusses a new algorithm to locate the global maximum of a function defined in a multidimensional rectangular domain. The number of dimensions is as large as, or even more than, 5 or 10. There are two important elements in this algorithm. One is the transformation of the object function in such a way that its global maximum corresponds to infinity while other secondary maxima are reduced to zero. Actually there is some departure from the ideal transformation because of possible overflow on the computer. This portion of the algorithm precedes the interactive (or conversational) use of a graphic display system. This interactive part makes the other element of the algorithm. A multidimensional point is represented as a curve on the display screen. By projecting numerous points in the multidimensional space to similarly numerous curves on the screen of the graphic display device, the human eye can make overall recognition much more efficiently than computers. This fact is exploited to reduce the problem to that of a set of unimodal peaks. Once the supporting domain for each of these peaks is separated by visual aid, one may leave the computer to handle the rest of the problem for itself. A number of numerical experiments are done and discussed to provide evidence regarding the feasibility of the proposed algorithm.

A Co-operative research project in Computer-Aided Learning

In 1967, the National Research Council (NRC) began a preliminary study of the application of computers as aids to learning. This initial work led to the establishment of a central research facility which is used by the NRC and a number of educational research organizations in a co-operative program of research into computer-aided learning. This central facility includes a medium-scale time sharing computer which is accessible to the participating organizations by means of remote terminals. A major objective of the project is to provide a facility which will allow the active co-operation of research workers throughout Canada in the development and evaluation of Computer-Aided Learning (CAL) systems to meet Canadian requirements. The NRC efforts are concentrated in the areas of development of terminal equipment, specialized computer facilities, and system programs. Examples of such development include audio tape and disc storage units, a transparent touch-sensitive tablet for computer input, alphanumeric and graphic display devices, line-concentrator systems and supporting-system programs. The co-operating educational organizations provide the facilities for the development and testing of course material and evaluation of terminal equipment. In some cases they assist in the development of system programs. The first participating educational organization to go “on line” was the Ontario Institute for Studies in Education in Toronto which was linked to the computer early in 1970. Since that time, the number of on-line participants has grown to six. The project provides a means for close communication between the educational researcher and the system designer. In this way, effective use can be made of available resources to arrive at a system specification which more closely meets the requirements of the user than might otherwise be possible.

An Interactive System for Chinese Character Generation and Retrieval

An interactive system for the generation and editing of Chinese texts using a small computer and a low-cost graphic display device is described. A unified structural approach is taken for character generation, character retrieval, and the defining of new characters. It is estimated that character-retrieval rates of the order of 30 characters per minute may be attained with this system. The system is suitable for use by persons having a working knowledge of Chinese.

REVIEW OF DATA PROCESSING AND INTERPRETATION METHODS IN GRAVITY AND MAGNETICS, 1964–71

This paper reviews the literature in data processing and interpretation in gravity and magnetic methods for the period 1964–71. The topics that are covered include gravimetry, reduction of data, automatic contouring, map analysis and filtering, interpretation technique, and applications. It is concluded from the literature that a very strong swing toward automatic processing and semi‐automatic methods of interpretation using computers has taken place in both methods during the time period under review. The key to further development in this direction appears now to be with making more imaginative use of graphic display devices.

Using moire patterns to determine the distortion of graphic displays and graphic input devices

Before high-accuracy graphic displays can be successfully designed or implemented from existing displays, the display distortion need be known to a high degree of accuracy-typically of the order of 0.1 percent of the display area height or better. Present day methods of measuring distortion are clumsy and imprecise. Methods of measurement using moire fringes have been suggested before, but the treatment was intuitive and the interpretation quailtative. In this paper are derived quantitative relationships from which display distortion to the 0.1 percent accuracy mentioned can be obtained using moire fringes. Two distinct methods are described. Full experimental methods, limitations, accuracy of method, etc., are given. Actual case examples illustrate the method. Although the methods developed here were specifically for TV-mode displays, the methods are equally valid for any graphic display device such as cathode-ray tubes (storage or refresh), electromechanical X-Y plotters, flat-screen displays, etc., the only requirement being the ability to display or generate a parallel line pattern. The distortion of graphic input devices such as TV cameras, electronic X-Y input pads, etc., can also be obtained using these methods.

Aircraft design augmented by a man-computer graphic system.

A status report is presented on one facet of a continuing research and development program at the Lockheed Georgia Research Laboratory in the application of man-computer graphic systems to the design and manufacture of aircraft. The program described is one of the initial steps contributing to the eventual evolution of a computercentric engineering/manufacturing/management system. It is being developed as a prototype covering the aircraft preliminary design and performance estimation process. This prototype will enable a creative design engineer to evolve and refine an aircraft configuration rapidly, by graphically and numerically describing aircraft components to a computer, using interactive, on-line, graphic display devices and unique, generalized graphic programs, by directing the computer through analyses of the configuration or components, and by reviewing directly on the computerdriven display the results of the analysis for approval or modification. A time compression of the preliminary design process of perhaps 10-to-l is one of the goals of this system. The system is discussed in general, and the graphic and analytical routines are described in some detail. Photographs show the graphic terminals being used in the execution of key steps in the preliminary design process.

Interactive Graphics in Data Processing: A system for implementing interactive applications

This paper discusses a system designed for interactive problem solving by use of a graphic display console. Existing application programs can readily be modified for use with a graphic display device, and the graphics programming can usually be done in a higher-level language. Based on intermediate results, the order of execution of application modules can be controlled from the console. The system description emphasizes the structure and generation of display formats for displaying output, for accepting user-defined commands, and for accepting data that is made accessible to the application modules. Also described is a generalized data structure and a set of experimental routines designed to adapt the structure to particular needs.