Xref: utzoo sci.electronics:2201 rec.ham-radio:3984 rec.autos:7200
Path: utzoo!mnetor!uunet!husc6!mit-eddie!ll-xn!ames!aurora!labrea!glacier!jbn
From: jbn@glacier.STANFORD.EDU (John B. Nagle)
Newsgroups: sci.electronics,rec.ham-radio,rec.autos
Subject: Re: Robocop spotted (Photo radar enforcement)
Message-ID: <17308@glacier.STANFORD.EDU>
Date: 11 Feb 88 05:37:17 GMT
References: <602@anasaz.UUCP> <9504@steinmetz.steinmetz.UUCP>
Reply-To: jbn@glacier.UUCP (John B. Nagle)
Organization: Stanford University
Lines: 29


     Gadgets like this, although rare in the US, have been around for
years in Germany and Japan.  But the radar/lidar approach really ought
to be replaced with a motion vision system which matched the images
from frame to frame and measured speed in that way.  The major problem
is that television resolution isn't good enough to read a licence plate
given a field of view that covers an entire road.  But once HDTV cameras
become generally available, this problem should go away.  Even without
HDTV technology, it may be possible to make this work, although it will
probably take one camera per lane.

     The major advantage of the video approach is that misidentification of the
vehicle can be much reduced, if not eliminated.  With a videotape as a
check, there's an objective but human-checkable record to be examined in
court when necessary.   This should make it a lot harder to be
falsely identified as the speeding car, while making it much easier to
get convictions in court.

     Digesting the data at TV rates is hard, but not impossible.  
Signal processing chips that can convolve images in real-time are starting
to become widely available.  (Any DSP5600 users out there, by the way?)
Note that the only exposed component of the system is the camera, and
cameras are not only cheap, but tiny.  (Pulnix has some very nice
cameras about 1" x 1" x4"; these are becoming popular with the robotics
people, especially when you want a camera near the end of an arm.)

     There could be a nice product opportunity here for someone.

					John Nagle