Newsgroups: sci.virtual-worlds
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!uw-beaver!milton!hlab
From: fenwick@clipper.ingr.com (Stephen Fenwick)
Subject: Re: Cheap head-mounted display
Message-ID: <1991May15.050816.28757@milton.u.washington.edu>
Sender: hlab@milton.u.washington.edu (Human Int. Technology Lab)
Organization: Intergraph Advanced Processor Division - Palo Alto, CA
References: <1991May10.205155.27367@milton.u.washington.edu>
Date: Tue, 14 May 91 16:07:08 GMT
Approved: cyberoid@milton.u.washington.edu



In article <1991May10.205155.27367@milton.u.washington.edu> cdshaw@cs.
ualberta.ca (Chris Shaw) writes:

>In article <LongerAndLongerAndLongerAndLonger> Greg ? writes:
>>It seems to me that a powerglove could be used for the position sensor 
>>(just aim it backwards, and put the receivers behind you) and still 
>>let you use a power glove for a glove.  
>
>The noisiness of the data given by the ultrasound sensors will drive you wild.
>You'll probably have to use a Polhemus Isotrak for head tracking.

Your tarring the whole technology with a too-broad brush.  Ultrasonics
can be used for reliable 2-d and 3-d positioning; I've done it.

The project was a derivation of a head-mouse for the Mac (forgot the name)
that used three receivers on a headband (one on top, one at each ear, all face
forward) and a single transmitter in a base unit placed on top of the Mac.
I'm not sure how much I can say about the techniques used (don't recall
what non-disclosures were signed at the time), but it was quite possible
to get reasonable 3-d positioning (one axis direct, two by translating
rotations to translations) based on a single 68HC11, some cheap glue
logic, and simple software.  Very little filtering (s/w or h/w) was required.

Send me e-mail for more details.

Steve Fenwick
-- 
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