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CIG Data Bases–Where are  We Headed?

Robert W. Beck, Program Engineer

and

Micheal R. Nicol, Visual Engineer

Aeronautical Systems Division

U.S. Air Force Systems Command

Wright-Patterson Air force Base

The rapid advancement in capabilities of computer image generation (CIG) visual systems has resulted in increased application of such systems from take-off and landing training to full-mission simulation.  These full-mission applications dictate a need for the creation of high-fidelity databases covering large geographical areas on the order of multiple thousands of square miles.  As a consequence, the manual techniques employed in the past to create small, airfield vicinity databases are not practical for generation of very large databases.  Clearly, some type of automated data base generation technique is required.  Current trends are aimed at utilizing the Defense Mapping Agency (DMA), CIG system constraints, and training utility of the end product limit the amount of automation possible in the data base generation process.  This paper discusses the evolution of the CIG data base generation process from total manual methods to current trends toward full automation.  Practical limits of automation and potential future developments are examined.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Automatic Transformation of the DMA DDB

For Real Time Visual Simulation

                Paul Hughett, Lead Systems Engineer for Data Base Software

Link Division, The Singer Company

This visual data base transformation program automatically transforms the Defense Mapping Agency Digital Data Base (DMA DDB) into a data base for real-time simulation of the B-52 electro-optical viewing system.  The user reviews the source data and specifies edge budgets, error tolerances, and visual/infrared models for DMA planimetry feature classes.  The DMA DDB is read re-blocked into standard geographical areas; data from different manuscripts, levels, and releases are merged into a composite source file.  The user may edit the composite source.  Then planimetry and terrain are independently modeled into visual/IR representations and progressively simplified (levelled) to meet the specified edge and error budgets at several levels of detail.  The leveled planimetry and terrain are integrated into a combined scene model and reformatted for real-time use.  Utility software facilitates production management and configuration control.  Significant advances include automatic level of detail generation, terrain modeling, planimetry/terrain integration, and a 100-fold speedup in data base generation.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Automation of Data Base Development In

Computer Image Generators

Timothy B. Cunningham and Gino O. Picasso

General Electric Company

Military requirements for large scale training missions on computer image generation (CIG) systems have placed increased emphasis on the CIG data base development process.  General Electric produces large scale data bases in a semi-automatic process involving the transformation and enhancement of Defense Mapping Agency digital data bases into CIG scene descriptors.  The enhancement process is the limiting factor in the evolution of a fully automated data base development system, and suggests a requirement for a single source data base.  Future General Electric CIG systems will incorporate automation technology to allow for low cost generation of visual scenes meeting strategic applications of specific weapon systems trainers.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Effective Antialiasing of Computer Generated Images

Dr. Geoffrey Y. Gardner and Edwin P. Berlin Jr.

Grumman Aerospace Corporation

Aliasing in computer generated image produces artifacts, which degrade training effectiveness.  A rigorous implementation of low-pass filtering required to prevent aliasing requires computation too extensive to be incorporated into real-time computer image generation (CIG) systems.  As a result, current CIG systems employ poor approximations to proper filtering, and aliasing still occurs.

This paper discusses the theory of image filtering and demonstrates a new real-time anti-aliasing technique developed from the theory.  The new technique represents a much closer approximation to the rigorous solution and therefore produces images of much higher quality than current real-time techniques.  At the same time it requires less computation.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Distortion Correction in Computer-Image

Generation-Based Wide Angle Visual Display Systems

Jerome T. Carollo and Nathaniel D. Reynolds

General Electric Company

Wide angle visual display systems used in flight simulation systems often exhibit distortion due to the display geometry and/or optics.  Distortion correction in the image generator permits the use of a wide variety of display systems with the assurance that the correct perspective of the environment is always presented to the viewer.  The paper will address the definitions of geometric and optical distortion followed by a discussion of some parameters relating to Computer Image Generation (CIG) and display system performance.  Several kinds of displays including domes, on-or-off axis infinity systems, will be considered, together with the image projection devices used in these displays, including unshapeable light value projectors with f-tan 0, f-0, or anamorphic lenses, laser displays, or dynamically changing projectors.  Some discussion of the distortion correction implemented on the Aviation Wide Angle Visual System (AWAVS) and Visual Technology Research Simulator’s (VTRS) two flight simulators CTOL and VTOL at the Naval Training Equipment Center (NTEC), Orlando, Florida will be presented.

This paper is available on the I/ITSEC Compendium CD-ROM.

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Computer Generation of Curvilinear Objects

Johnson K. Yan

Link Division, The Singer Company

This paper surveys alternative approaches to curvilinear object generation by computer.  These alternative approaches are compared in terms of ease of generation of silhouettes of objects, ease of intensity computation, ease of texture generation, image quality, data base compactness and flexibility of modeling free-form curvilinear objects.  The alternative approaches surveyed are planar surface approach, quadric surface approach and parametric surface approach.  Other techniques within the class of parametric surfaces, which appear to be promising, but have not yet been tried are also discussed.

This paper is available on the I/ITSEC Compendium CD-ROM.

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Joining Techniques for Optically Combined Visual Display Systems

Jerry L. Bentz

McDonnell Douglas Electronics Company

Since the introduction and FAA certification of VITAL in March 1972, computer generated image display modules containing a spherical mirror, beamsplitter, and cathode ray tube (CRT) have become very familiar to flight simulator visual system users.  Increased utilization of simulators has created the need for expanded visual system fields of view.  CGI techniques and creative variations to these basic display modules are satisfying this need.

In less than one decade, visual display systems have progressed from single module, single channel to multiple channels using optically combined modules.  To provide for these broader requirements, McDonnell Douglas Electronics company (MDEC) has developed three separate approaches employing optical combining techniques.  They are modular, wide field of view and zero gap.  All are capable of being optically joined into multiple module configurations with overlapping imagery, and each exhibits a different set of tradeoff considerations.  This paper discusses field of view (FOV), and describes the joining characteristics for each technique.  It concludes by presenting photographs of imagery from our latest configurations, the wide Field of View and Zero Gap overlapped displays.

This paper is available on the I/ITSEC Compendium CD-ROM.

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High Output–High Speed Video Images Projector Adapted to the Simulation Needs

Francois Desvignes et Jean R. Huriet

Societe Anonyme d’Etudes et Realisations Nucleaires (SODERN) France

The main specifications, for the visual displays associated with military aircraft simulators are first recalled; they take into account the eye properties for spatial resolution, color and speed of response.  These specifications are examined from the point of view of simulator design and video-to-visual image converters.  The features of a new projector developed by SODERN are then briefly described and their adaptation to simulator needs are discussed.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Behavioral Bases for Determining Vehicle Detailing In Simulation Displays

Dr. Brian L. Kottas and Dr. David W. Bessemer

United States Army Research Institute for the Behavioral and Social Sciences

Effective representation of armored vehicles in simulation displays demands a careful evaluation of human perceptual capabilities.  This holds especially true for computer generated target displays, which must provide sufficient detail to allow vehicle identification within limitations of computer processing time and display resolution.  Even in image generation and display systems not incurring such limitations, the image detail need not exceed human perceptual and cognitive information processing capabilities.  Providing excessive detailing of targets may, in fact, produce negative training by allowing those being trained to depend on information unavailable in combat for target identification training and its implications for target displays are discussed.  Estimates are presented for the visibility of features of threat and friendly main battle tanks, based on analysis of past empirical research done under ideal visibility conditions and visibility data from past research.

This paper is available on the I/ITSEC Compendium CD-ROM.

Order it from I/ITSEC’s Website.

Training Techniques Using Computer Generated Imagery (CGI)

David B. Coblitz