"Bill Wright" wrote in message
news
On 06/06/2018 19:58, Cynic wrote:
We've got simple cctv cameras with IR illuminator around the lens up at
the local hall. Lately there's been a problem with boy racers gathering
after dark in the car park and antisocial behaviour ensues.
The cars can be viewed but reflective number plates are just a washout
presumably caused by the direct reflection of the IR. Has anyone had
success in capturing readable images of number plates after dark using
economic cameras? I'm guessing the use of a non illuminated camera with a
separate illuminator from an angled location might solve the reflection
washout of the image but the hall doesn't want to spend funds without
being sure it will work.

No-one else has even tried to answer your question. They have been too
busy acting like barrack room lawyers.

The problem is partly that reflective number plates dazzle the camera,
partly that the number plate will be grossly over-exposed because it
reflects the IR, and partly that the shutter speed will be automatically
low so there will be motion blur.
There is no easy solution.

The ANPR cameras must have found it.

You might do better to aim for clear identification shots of the bikes and
riders.

Makes a lot more sense to do it the way the ANPR cameras do it.

One way is to have a reasonable level of visible light (30W LED floods)
and a camera with a big lens set for a fast shutter speed. Pre-focus on
the roadway because the depth of field will be poor. Set the camera so it
doesn't switch to monochrome, since colour aids identification.