Towards the Rapid and Complete Automated Alignment of Multi-Projector Display Systems

Charles J. Lloyd, Optical Engineer
Michael D. Christopher, Software Manager
David A. Beane, Software Engineer
BARCO Simulation

Dr. David L. Flannery, Software Engineer
Third Rock Engineering, Inc.

From the Proceedings of the 2003 IMAGE Society Annual Conference, Scottsdale, Arizona.

Towards the Rapid and Complete Automated Alignment of Multi- Projector Display Systems Towards the Rapid and Complete Automated Alignment of Multi-Projector Display Systems


Abstract

This paper summarizes the functions and performance of an Automated Alignment (AA) system installed a year ago in four C-130 Hercules flight simulators at Little Rock AFB. This system accurately and completely adjusts geometry, convergence, and the co-alignment of blend zones within two minutes per channel, fast enough that these functions can be completed between training sessions if desired. Additional capabilities include the automatic adjustment of static and dynamic focus, and the adjustment of peak white, white balance, color tracking, and black level across channels. Requiring only five to seven minutes per channel, it is practical to run these functions on a weekly ba sis if desired. Since the system measures complete gamma functions for each CRT, these data can be passed to the IG on a regular basis for updating gamma correction tables.

Test results show that the spatial errors introduced by the AA system are small as compared with the system level geometry and convergence tolerances for the display system. At this level of measurement precision, it has become practical to guarantee that automated spatial alignments are at least as good as the best manual alignments. A comparison of the channel-to-channel variation in luminance and color after manual and automated adjustments revealed the residual variance after automated adjustment was one third of the variance after manual adjustments.

For years, flight simulator customers have expressed a strong desire for display system resolution levels that far exceed the capability of currently available (affordable) display technologies. The realization of "eye-limiting" resolution for Level D commercial flight simulators would require some of 30 to 60 M pixels, whereas the typical simulator of today produces only 4 to 8 M pixels. This author suggests that the use of comprehensive, accurate, and reliable AA systems is the logical next step in the evolution of flight simulator display systems design. The past few years have seen a strong trend towards the use of more, smaller, and less expensive image generators for flight simulators. Numerous parties have promoted the use of more, smaller, and less expensive projectors as well.

The use of comprehensive, accurate, and reliable AA systems is essential to the success of this approach.