Re: Speed camera question


"Mike Harrison" <mike@xxxxxxxxxxxxxxx> wrote in message
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On Thu, 2 Feb 2006 13:44:24 -0000, "The Electric Fan Club"
<ian.shorrocks@xxxxxxxxxxxxxxxxxxxxxxxx>
wrote:


"Alan Holmes" <alan.holmes@xxxxxxxxxx> wrote in message
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"The Electric Fan Club" <ian.shorrocks@xxxxxxxxxxxxxxxxxxxxxxxx> wrote
in
message news:43e0768a$1_1@xxxxxxxxxxxxxxxxxxxxxxxxx

"Ken" <autosuggestion54@xxxxxxxxxxx> wrote in message
news:1138709076.238934.259340@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

If it was a rearward facing Gatso camera, then it works by taking 2
photographs as your vehicle passes spaced markings on the road
surface.
Calculating the speed is easy......you just work out the distance
travelled and time elapsed between photos.

A motorcyclist recently had Gatso conviction quashed as speed
recorded,
was double what the photographic evidence suggested to be actual
speed.

Ask for the photos and work it out for yourself..............also ask
for calibration certificates for camera that took pics in your case.


Remembering the guy in Walsall who discovered that the time between the
photos on the camera that flashed him was 680 milliseconds. Since it
is
supposed to be 500 milliseconds, this made 30 mph look like 41 mph. He
discovered that the GATSO specification states that the time between
photos is 'user adjustable', which is why he decided to measure it.

He went on to discover that out of 20 cameras he checked, 16 had
intervals greater than 600 milliseconds and all were greater tha 500.

How on earth did he measure the interval. what equipment did he use, and
is it freely available?

A simple camcorder can be used easily to measure the interval to the
nearest 40mS (maybe 20ms if you
can fo field stills, as opposed to frames).

He measured it far more accurately than that. The camcorder method would
fail if one (or both) of the flashes occured when the CCD was not recording
light - which they do because they have an electronic shutter on them.


.

Relevant Pages

  • Re: Speed camera question
    ... > photographs as your vehicle passes spaced markings on the road surface. ... > A motorcyclist recently had Gatso conviction quashed as speed recorded, ... > for calibration certificates for camera that took pics in your case. ... supposed to be 500 milliseconds, this made 30 mph look like 41 mph. ...
    (uk.legal)
  • Re: Speed camera question
    ... If it was a rearward facing Gatso camera, then it works by taking 2 ... for calibration certificates for camera that took pics in your case. ... The shutter will typically be open for most of the frame period, ... the box for the benefit of photographs that appeared on the internet at the ...
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  • Re: Speed camera question
    ... If it was a rearward facing Gatso camera, then it works by taking 2 ... photographs as your vehicle passes spaced markings on the road ... for calibration certificates for camera that took pics in your case. ... I don't know what the typical flash duration is on ...
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  • Re: Speed camera question
    ... >> A motorcyclist recently had Gatso conviction quashed as speed recorded, ... >> for calibration certificates for camera that took pics in your case. ... > photos on the camera that flashed him was 680 milliseconds. ... > He went on to discover that out of 20 cameras he checked, ...
    (uk.legal)