license plate camera

TechBill

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I am aware we can take a standard bullet camera and adjust the setting to turn it into a camera intend for license plate scanning. Does Dahua sell camera already design for license plate scanning?
 

wittaj

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If by scanning, you mean that you can visually read the plates on the screen as opposed to the camera itself reading and logging, then yes, any Dahua camera can be set up to read plates.

It comes down to three parameters - optical zoom, shutter speed, and angle.

You need enough optical zoom to make the plate as large as possible in the field of view. Ideally, the field of view should have the vehicle and not much else, so it isn't an overview camera.

You need to try to get as much as a straight on angle as possible, which is why most of us get a high powered optical zoom so we can point it down the street and "flatten" the angle.

You need to run the camera at a fast shutter in order to capture the plate. Shutter speed is more important than FPS.

At night, we have to run a very fast shutter speed (1/2,000) and in B/W with IR and the image will be black. All you will see are head/tail lights and the plate. Some people can get away with color if they have enough street lights, but most of us cannot. Here is a representative sample of plates I get at night of vehicles traveling about 45MPH at 175 feet from my 2MP camera (that is all that is needed for plates):

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If you distances is closer than 30-40 feet, then this camera will work:


If you distance is more than that, up to about 230 feet, then this will work:


Under some ideal conditions, you may get a fixed lens to work, but that is more like a parking lot and slow speeds. It is best to go with a camera with more zoom than you think you need because almost everyone underestimates distances.
 
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