Buckinghamshire CC ANPR cameras
bdm at fenrir.org.uk
Mon Feb 6 21:47:54 GMT 2012
On Mon, 06 Feb 2012 20:15:54 +0000
Peter Tomlinson <pwt at iosis.co.uk> wrote:
> So what do the
> TrafficMaster people, who help us by warning of congestion ahead on
> motorways, do?
According to what I read back in the 90s I think, they claimed that
they were scanning only the centre part of the registration plate and
then tokenising that, then only looking at that token over a couple of 4
mile segments, or possibly only one, and estimating traffic flow based
on the known percentage of cars that turn off main roads.
But later information about police requests for TM's data relating to
motorway journeys makes me wonder if that was a convenient untruth, I
don't have the links but it was claimed that their data was used to
convict the perps of a murder in Scotland where the travelling was done
via the motorways.
Since reg plates are not in one fixed position on vehicles it would need
a pretty complex algorithm to find the plate and then look only at one
part of it, particularly as some plates have all characters in a line
and others are split into two rows.
bdm at fenrir dot org dot uk
"Arguing with an engineer is like wrestling with a pig in the mud;
after a while you realize you are muddy and the pig is enjoying it."
GnuPG key ID DE32E5C5 - http://wwwkeys.uk.pgp.net/pgpnet/wwwkeys.html
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