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Red light camera countermeasures?

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Barry Gold

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Aug 27, 2010, 10:22:16 AM8/27/10
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I'm wondering if red light cameras could be defeated by a simple
slave strobe.

A slave strobe is used in photography to fill-in lighting. You have
the principal strobe mounted on or near the camera, as usual, but you
have one or more other strobes around the room that will light the
subject from different angles.

When the main strobe flashes, the slave detects the light pulse and
also flashes. To the camera (probably using a shutter speed of around
1/50 second), the combined flashes -- each 1/1000 second or less -- look
like a single flash and give a nice, rounded lighting on the subject.

But suppose you mounted a slave strobe directly over each of your
license plates. The red-light camera detects your car about to enter
the intersection. It takes a picture; the process usually includes
flashing a strobe light to get adequate exposure, even at night. A
few hundred microseconds later, your slave strobe flashes in response.

The resulting light coming back at the camera should overexpose the
photo. They will probably get a good picture of _you_, but your
license plate should be completely unreadable. They need the license
number to know who to send the ticket to. (At least until facial-
recognition software gets a lot better.)

You can buy slave strobes for under $30 on Amazon.

Any thoughts?

--
Barry Gold, webmaster for:
Conchord: http://www.conchord.org
Los Angeles Science Fantasy Society: http://www.lasfsinc.org
My blog: http://goldslaw.livejournal.com/

ji...@specsol.spam.sux.com

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Aug 27, 2010, 11:41:37 AM8/27/10
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Barry Gold <bg...@nyx.net> wrote:
> I'm wondering if red light cameras could be defeated by a simple
> slave strobe.
>
> A slave strobe is used in photography to fill-in lighting. You have
> the principal strobe mounted on or near the camera, as usual, but you
> have one or more other strobes around the room that will light the
> subject from different angles.
>
> When the main strobe flashes, the slave detects the light pulse and
> also flashes. To the camera (probably using a shutter speed of around
> 1/50 second), the combined flashes -- each 1/1000 second or less -- look
> like a single flash and give a nice, rounded lighting on the subject.
>
> But suppose you mounted a slave strobe directly over each of your
> license plates. The red-light camera detects your car about to enter
> the intersection. It takes a picture; the process usually includes
> flashing a strobe light to get adequate exposure, even at night. A
> few hundred microseconds later, your slave strobe flashes in response.
>
> The resulting light coming back at the camera should overexpose the
> photo. They will probably get a good picture of _you_, but your
> license plate should be completely unreadable. They need the license
> number to know who to send the ticket to. (At least until facial-
> recognition software gets a lot better.)
>
> You can buy slave strobes for under $30 on Amazon.
>
> Any thoughts?

You mean other than the cameras take more than just one picture, often
from multiple cameras from different directions, and the newer ones
aren't still cameras, they are short video clips?

--
Jim Pennino

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