From: jmelzer@aol.com (JMELZER)
Subject: Re: TECH: Cheapest or more efficient Head Tracking Tecnology
Date: 15 Jan 1997 06:03:09 GMT
Organization: AOL http://www.aol.com



>I know some of the technologies used (as magnetic by >Ascension and
Polhemus for example), but I'm asking why
>the Ultasonic way isn't very used?

Ultrasonics have been used in the past, but have never caught on due
to acoustic interference. Other ideas are infrared (light
interference), mechanical (tethering problems), video (processing
problems). There is no fool proof solution. If you try a literature
search, you should run across a few SPIE articles dating from
1992-1994 or so that review the technologies.

I might suggest, however, that you consider one of the new
"sourceless" tracker technologies such as the one by General Reality
(try www.genreality.com). (I don't own/sell/work there, so I have no
vested interest).  These are quite interesting and relatively
inexpensive.

Regards,

Jim Melzer
jmelzer@aol.com (JMELZER)