The projector has been chosen

Ultimately, we were able to limit number of projector choices down to four by looking only at short throw projectors that provided the required screen size.  Many of the high-end ultra short throw projectors actually produced a screen size that was far too large.  This eliminated many of the super heavy duty projectors to reveal smaller and cheaper models with great resolutions.


After making sure that the projector had a short enough throw and a small enough screen, we evaluated them on the quality of the image.


Brightness
Because the multitouch screen will likely be placed in a relatively brightly lit lobby, we needed to look at high-lumen projectors.  The lumens of the projectors we considered ranged from 2000 - 3000 ANSI.


Resolution
In order to choose a projector with a crisp, sharp picture, we evaluated each projector on resolution.  All of the projectors that we considered supported a resolution of at least 1080i, while only one projector supported 1080p.  However, since our particular project was not intended for action movies or fast-paced games, the difference between 1080i and 1080p was rather insignificant.


Lamp life
In order to ensure that our touchscreen is affordable in the long run, we had to look at the rated life of each projector's lamp.  Lamp life ranged from 2000 to 6000 hours (a 3x difference!).


Other considerations
We also considered other projector properties, such as contrast ratio (higher is better), inputs (preferably HDMI, DVI, or VGA), price, and whether it was 3D ready (could we combine 3D and multitouch?).


The Winner
Ultimately, the winning projector was the ViewSonic PJD7382 DLP Projector.

This projector had a brightness of 3000 ANSI, a 1080i resolution, a lamp life of 4000-6000 hours, a static contrast ratio of 2600:1, a dynamic contrast ratio of 3000:1, two VGA inputs, and is 3D ready.


With this projector in mind, we can now begin to finalize our dimensions!