A Wide Field-of-View CRT Projection System with Optical Feedback for Self Alignment,
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 16, 1983
- Accession Number
- ADP003447
Entities
People
- P. Lyon