From: dstamp@watserv1.waterloo.edu (Dave Stampe-Psy+Eng)
Subject: Re: head tracking
Date: Wed, 27 Nov 1991 19:04:44 GMT
Message-ID: <1991Nov27.190444.18117@watserv1.waterloo.edu>
Organization: University of Waterloo


azuma@cs.unc.edu (Ronald Azuma) writes:

>        Gary Bishop explored this idea in his 1984 thesis work [1][2].  By
>placing an array of "smart" 1-D image sensors on the user's head and comparing
>the differences between two images taken at different times, it should be 
>possible to detect changes in the head's position and orientation.  The 
>faster you can run the system, the smaller the image differences will be, 
>which in turn means your image sensors can be simpler, easier to build, and 
>faster.  In theory, this scheme does not require modification of the 
>environment.  
>
>        However, making a robust working system out of this concept is non-
>trivial.  Phil Jacobsen, a PhD student here, is continuing the work that Gary
>initiated.
>them.  These "cameras" are really lateral-effect photodiodes, which return
>the centroid of a blob that gets imaged on them, which means we don't have to
>spend lots of time on image-processing algorithms.  Jih-Fang Wang built a 
>three-"camera," three LED, benchtop prototype of this system [3][4].

Can you describe the optical system used?  I've been looking at how to
convert hand-scanners to sensing the 1D position of LED's, but I'm having
troubles with a cheapie solution to focusing the unwanted dimension
onto the line of sensors.  This could be a reasonably low-cost way to
do fast tracking (>400 samples/sec).  Any help would be appreciated.

--------------------------------------------------------------------------
| My life is Hardware,                    |                              | 
| my destiny is Software,                 |         Dave Stampe          |
| my CPU is Wetware...                    |                              | 
| Anybody got a SDB I can borrow?         | dstamp@watserv1.uwaterloo.ca |
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