How to improve night intrusion detection for a HDW-3841T-ZAS camera

[gregip]

I'm having a lot of trouble getting this camera to set off an intrusion alarm at a 40m range at night. Daytime intrusion detection at this range, and further, works well.
The onboard IR is supposed to be good for 50m (yes I know it is probably overstated). Even if I supplement this with a 18W LED IR spotlight at a 30m range shining on the 40m target 10m away from the spotlight, it does not detect a person. Fiddling with the shutter speed and gain has not improved the situation. Switching off the onboard IR and relying on the IR spotlight seems to just confuse the camera and it loses focus.
Any suggestions or a link to some information to help me figure it out?

 

[wittaj]

First that is 8MP on a 1/2.8" sensor, which is the same sensor used on 2MP cameras, so you need 4 times the light of the 2MP. That directly impacts the range capability of that camera.

At night, you gotta cut the rated IR at least in half or more.

If adding external IR didn't help then you should consider a better camera on the proper MP/sensor ratio as well as a camera with more optical zoom. 40m at night with that focal length is going to be tough.

But post some video and screenshots of your settings and we can see if we think there is any changes that could improve it.

 

[gregip]

Thanks for the offer wittaj. Here's some screenshots of the night profile settings....
These are all from the camera GUI, not the NVR.

 

[wittaj]

Those are decent settings. My suggestions that might help night detection include:

• Increase shutter to 16.67
• Decrease gain to 69
• Turn on 3D NR and try 40
• Add contrast - all of those settings you have at default - I would adjust those at night to get you a good image, but try not to go over 70 for any of them. And have contrast be about 7 numbers higher than brightness.

Let's see if that helps get you some detection at that distance.

 

[gregip]

We have some improvement thanks wittaj.
Switching ON the 3D-NR helped the image quality quite a bit and I changed other settings as follows:
Brightness from 50 to 60
Contrast from 50 to 70
Shutter from 10 to 17
Gain from 80 to 70
I went for a walk and the intrusion alarm worked when I was lit up directly in front of the IR spotlight but otherwise only a ghost of me was present and no intrusion detected.
I'll move the IR spotlight back a bit to light up a wider area and try again tomorrow night.

Is there a Dahua document that explains in more detail all these different settings and how they interact with each other? The Dahua network camera operation manual does not explain much.

 

[wittaj]

Glad to see it is helping.

The IR spotlight should help now for sure.

Unfortunately that network camera operation manual is about as good as it gets LOL.

Change the illuminator from auto to 100 and see if that helps with the peripheral areas.

 

[gregip]

Unfortunately the intrusion detection range is still pretty poor at night even when I move the IR spotlight further away from the target sheds to get a better spread.
It picks me up when I'm directly in front of the IR spotlight but not otherwise.

That leaves me three choices I think:
(1) buy more IR spotlights to light up the area. Too expensive and a pain to have cables and spotlights all over the place.
(2) buy white light sensor lights so that the sheds are lit up with white light. Also too expensive and also a pain to have cables and sensor lights all over the place.
(3) buy a better/more suitable camera. Possibly the least expensive but it would be a neat and simple solution.

Any recommendations for a camera that will do this - that is have reliable night intrusion detection at a distance of over 40m with its own IR lights?
I would still use the current IR spotlight to supplement the camera's IR.

 

[sebastiantombs]

Motion detection at night is very brightness and contrast dependent. It takes some experimentation to find the right combination and any change in lighting, like the difference between a clear night and a cloudy, rainy, night will have an effect as well. You're fighting an uphill battle because of the sensor size/resolution of that camera. If you can, consider replacing it with a 5442T-AS in a fixed focal length or a 5442T-ZE with the varifocal lens. You'll get the best results if you can get away with a fixed focal length though.