Accession Number : ADP003447

Title :   A Wide Field-of-View CRT Projection System with Optical Feedback for Self Alignment,

Corporate Author : EVANS AND SUTHERLAND COMPUTER CORP SALT LAKE CITY UTAH

Personal Author(s) : Lyon,P.

Report Date : 16 NOV 1983

Pagination or Media Count : 9

Abstract : Evans & Sutherland has developed a multi-channel CRT projection system. This system uses microprocessor technology with optical feedback to provide self-alignment for color-hue, intensity, color-convergence, geometry, and focus. By replacing drift-prone analog correction circuits with digital circuits and D/A converters, system drifts are limited to gain and offset errors. These errors are optically detected and corrected in real-time by the microprocessor. Geometry drifts can be detected and corrected to within 1/4 of a pixel. Because this projection system is CRT based, image generator, lens, and projection angle induced distortions as large as 30% can be corrected by the projector's digital electronics. The projection system self-alignment capabilities together with edge matching make possible the tiling of multiple channels. This facilitates improved brightness and resolution over wide fields-of-view. A six channel system, with 30 degree by 30 degree fields-of-view for each channel, using a 12 foot radius screen of unity gain yields 7 ft-lambert brightness with better than 3 arc-minute resolution. (Author)

Descriptors :   *Cathode ray tubes, *Image projectors, *Training devices, Multichannel, Microprocessors, Optical properties, Feedback, Alignment, Self operation, Circuits, Digital Systems, Drift, Errors, Corrections, Digital to analog converters, Brightness, Resolution, Line of sight, Wide angles

Distribution Statement : APPROVED FOR PUBLIC RELEASE