Night Licence plates

[tman2]

Hi All,
I have a Dahua SD5A425XA-HNR.

At night, it has a strong IR light and lights the scene well. What I've discovered of course is that since licence plates are highly reflective, they are overexposed and unreadable. Default Exposure Compensation is set at 50. (Scale 0-100). This works brilliantly except for the licence plates. I can change it to 0 then plates read well, but the scene is dark. This is a zoom camera that is directed by another overview cam.
The security issue is suspicious vehicles parking for periods of time up to 2 hours. I need both licence plates as well as a well lit scene.

So, I was looking to make a rule on my software (NXWitness) that would reduce the exposure via a htpp/api request for the first 2 minutes of the alert for example, and then to change back to standard exposure.
Does anyone have any experience in adjust a Dahua camera exposure via http?
Cheers,
Tristan

 

[wittaj]

LPR is as much an art as it is a science.

We have found that PTZs are problematic for LPR because of the focus issue when the shutter speed increases because it needs something to focus on.

Now in your scenario if you are using it as a fixed cam it may work, but if you are using the tracking capabilities of the camera and it is zooming in/out as a plate goes by, it won't work.

See this thread:

Dahua http api for setting the focus

I have the Dahua PTZ model: DH-SD59225UN-HNI running on the latest firmware available on Dahua's website. I need to run automations on it using http API calls. So far i am able to move the cameras where i want to and even zoom on the correct level. For example here is the api call for moving...

ipcamtalk.com

And this subforum:

LPR

Licence Plate Reader cameras

ipcamtalk.com