License plate detection - 200 feet away - PTZ?

[wittaj]

I am sure one exists (maybe), but I have not found a PTZ that you can force a focus number on like you can with other Dahua varifocal cams.

Without the ability to be able to force a focus and have it hold all night, it will be useless running at the shutter speed needed to capture a plate at night.

 

[BigLarge]

My new Z12 is doing well for license detection. A few issues;

It appears the max frame rate is 25 FPS. This doesnt appear to be enough for faster moving vehicles. Any way to alter or improve this?

Also, with my shutter speed reduced to 1/30000 my IVS doesnt trip at night anymore. Should I just try motion detection, instead, at night?

 

[wittaj]

@BigLarge - FPS isn't the issue for capturing plates.

My LPR cam is doing 6 FPS.

Shutter speed is what captures the clean pictures, FPS just makes the video itself appear smoother. Do you want a smooth video of a car driving by, or a nice clean capture of the plates!

A 1/30,000 shutter speed is crazy fast for night. Most run 1/2,000 at night and get the plates well. The camera does have to be in B/W though.

All of the above is for taking a fixed camera and turning it into LPR duty, but the logic would be the same for a PTZ.

Is your PTZ able to focus at night at a fast shutter speed and get plates? That seems to be the limiting deal for most PTZs is you cannot force a focus like you can with a fixed cam.

 

[bigredfish]

I’ve found there can be an advantage to more FPS with LPR . More frames can be helpful when the plate is only visible for 1/2 second.

But agree 1/2000 should be plenty.

I run both IVS and MD as like you sometimes IVS will miss if you’re zoomed in at 1/2000 at night.