From: geoffrey@cantua.canterbury.ac.nz (Geoff Thomas)
Subject: Re: Tracking of Targets
Date: 23 Jun 91 01:12:43 +1200
Message-ID: <1991Jun23.011245.1167@csc.canterbury.ac.nz>
Organization: University of Canterbury, Christchurch, New Zealand




In article <1991Jun20.232119.3115@milton.u.washington.edu>, mgobbi@cs.ubc.ca 
(Mike Gobbi) writes:

> I would suggest that the target wear a small radio/sound transmitter,
> and the camera have 5 directional pickups (one aimed "straight", the others
> "up", "down", "left", and "right" by about 5 degrees).  The camera would be
> aimed by swinging it in the direction of the stronger signal in the
> vertical and horizontal planes.  If the "straight" pickup has the best
> signal, the camera is held steady.
> 
> This has the problem that it must start out aimed at the target, and if
> the target moves faster than the device can rotate it will lose it.  There
> are probably numerous technical problems as well, since I'm not a radio
> expert, but I think it might work.
 
I had an idea a year or so ago, to do this sort of thing, but I thought of 
using a phase detector and 3 microphones / aerials at the camera end.

The mics/aerials would be set apart in an L - shape, so that each arm is 
about 1/4 of the wavelength of the transmitted signal (from the target). The 
phase detector I thought might work was a "balanced ring modulator" or 
something like that, and it's output was a voltage proportional to the phase 
difference between 2 input signals (of which

This set-up *might* work! (I haven't actually tried it yet)

Hope it helps.


Geoff Thomas		"Baby drools, oh no!"