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detrimental in theory, depending on the case, but in practical applications the difference would be
neglectably small. Finally, by sacrificing the non-overlapping parts of the images and presenting them
as black, even this small effect can be removed.
The shutter disc is made of acrylic plastic sheet. The opaque areas are covered with metallic paint. The
disc is balanced after coating to eliminate vibrations and noise. The diameter of the disc is 160 mm.
The projected image covers a sector of 38 degrees from the disc. Therefore, the opaque sector is
218 degrees wide. So about 40% of the projectors light output is transferred to the screen. The
attainable light output is comparable to a single DLP-projector stereo setup. [5]

EXPERIMENTAL RESULTS

The implemented prototype performs as expected. The use of the 100 Hz refresh rate per eye resulted
in a completely flickerfree image. The disc type shutter is rotated by the brushless DC-motor that has
offered reliable and maintenance free operation for thousands of hours. The projectors used in the
prototype have an XGA resolution and 1100 ANSI lumens of light output. With a 3m width of
projected image the overall brightness could be better but still is entirely comparable to a projected
CRT image. All other characteristics like the sharpness, the spatial stability and the lack of flicker are
superior when compared to the CRT counterpart. The constructed prototype has been applied to a
person lift platform training simulator system. The simulator has been in everyday use for more than
two years now, and the reliability of this new method of stereo projection has been field proven.

CONCLUSION

The described method for producing stereo projection was proven very functional. The major
advantage of this method is the high stereo multiplexing rate. It is now possible to use sufficient rates
without sacrificing any of the important properties of the projected image.

Possible enhancements in the light output and/or resolution are simply achieved by selecting a proper
type of LCD projectors. The stereo projector adjustments can be made even easier when both LCD
projectors are located on the same optical axis. This could be done with full or semi-transparent
mirrors.

REFERENCES

[1] Helmut Jorke, Markus Fritz, "Infitec - A new stereoscopic visualization tool by wavelength
multiplex imaging", Infitec GmbH
[2] Bridgeman, B. and Montegut, M. 1993. Faster flicker rate increases reading speed on CRTs. SPIE
Vol.1913 Human Vision, Visual Processing, and Digital Display IV. PP. 134-145.
[3] Christie Digital Systems, Inc. Web site: http://www.christiedigital.com/

[4] Ian McDowall, Mark Bolas, Dan Corr, Terry Schmidt, "Single and Multiple Viewer Stereo with
DLP Projectors", Fakespace Labs, Christie Digital Systems

[5] Barco nv. Web site: http://www.barco.com