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We started off our investigation of the Geowall by using the simple Viewer software available and Mars Rover images. We used two old Sharp LCD projectors for our initial investigation. The projectors were placed on two shelves in a storage cabinet. We used polarized glasses and plastic 3” x 3” filters obtained from Reel3d (no longer around – see American Paper Optics, Inc.) and Rainbow Symphony Inc. Simple cardboard holders were used to contain the plastic filters. These holders were taped to the lens hoods. The three dimensional effect was not great – but it was possible to see some of the stereo effect.
We didn’t know a lot about how LCD and DLP projectors work so we did some research. These were some useful sites: Overview of the two technologies: http://www.projectorcentral.com/lcd_dlp.htm TI’s explanation of how DLP’s work is available at DLP Technology. Click on “Launch our Demo.”
We planned on ordering the usual Infocus LP530 projectors, but they were no longer available. Rob Gag at projectorpoint.com recommended NEC LT240 projectors. I believe that they are somewhat smaller than the LP530 projectors. We purchased a Chief ASU2000 projector stacker to hold the projectors. The projectors and portable screen are setup in the VisLab –
The projectors mounted in the stand
Side views of the projectors:
Above, we have constructed a filter stand compliments of the physics department. The top filters the left eye and the bottom filters the right eye.
The projectors have the usual keystone correction. In addition, they have cornerstone correction. The cornerstone correction allows one to move the 4 corners and 4 sides individually. This makes it possible to get a very precise match on both images. However, it does take extra time to adjust the cornerstone.
The 530 lens holder fits on NEC’s lens hood – but it does not fit securely. We purchased Hoya 72 mm polarizing filters in swivel mounts. We are currently experimenting with filter holders for these glass filters.
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