🚀 go-pugleaf

In article <1992Nov18.010237.6001@ole.cdac.com>, ssave@ole.cdac.com 
(The Devil Reincarnate) writes:
> In article <1durunINNc91@coyote.cs.ubc.ca> harrison@cs.ubc.ca (James Harrison) writes:
>>
>>We have an application for the tracking of the position of a person in
>>a larger room with little or no hardware carried by the person being
>>tracked.  What we would ideally like to do is know the position of the
>>person in a large room (x, y).
>>
>>Anyone done this?  Know it can/can't be done?
> 
>   Try the IR movement detectors. A sharp enough definition would give an X-Y-Z
> position if the three detectors were placed on two adjacent walls and the ceiling.

I don't believe that this will work.  According to what I've read about these
devices, they contain just one IR pickup.  Therefore they can't tell where
anything is, even in a single dimension.  They can only tell that something is
moving, somewhere, across their field of "vision". 

How it works:  The IR detector is placed behind a curved Fresnel lens.  The
lens divides the field into in-focus and out-of-focus areas. As an IR source
moves across the field, the IR detector "sees" alternating high and low levels
of IR. 

A simple high-pass filter (with cutoff at a few Hz or so) and pulse detector
does the rest.  They aren't sensitive to stationary heat sources, or slow-
moving ones like the sun, because these do not generate pulses fast enough,
or at all. 

	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
Uucp:  ...{crash,eisner,uunet}!cmkrnl!jeh