Do tripwires work at night with IR illumination?

Wallop

n3wb
Feb 21, 2025
16
6
New Zealand
My camera is a IPC-T54IR-ZE-S3 and the tripwire seems to be hit and miss at night. The only light source is moon/star light. The IR on the camera is working and smart ir is disabled.

Cheers

Mike
 
Generally speaking yes.

But like any scene, day or night, the placement, sensitivity, and other image settings can make it work better or worse.

Show us your scene with the tripwire and settings
 
Typically if it doesn't work at night you are trying to do too much with one field of view.

As requested, please post your field of view with IVS rules shown and we can tell you almost immediately if it should work.

Also, you have to not be using auto/default settings and dialed the camera in to your field of view for brightness, contrast, shutter speed, etc. to get the best performance.
 
The trip wires are in the foreground and people / objects are passing behind not through them. The clue here is look at the wires in relation to the tree trunks. You need to think 3 dimensionally.

Where is it you want them to be tripped? If someone passes through the trees? Walks down the public footpath? Comes down the road? That's going to affect your placement. When I put one of my cameras up I had some placed horizontally for people to cross, and they were walking behind the ends despite drawing them in a manner that appeared to competely block the path area I was protecting. I could watch people live on video walk through the scene behind them. I had to re-draw them.

eg. If I was trying to trigger on the footpath, I'd be drawing them horizontally front to back in the picture and taking the ends right out to the edge of the verge from the front edge of the picture.

I'd also add in a hortizontal trip wires left to right to cover someone walking throuigh the trees towards the camera as that's the main area you need to protect anyway. LIttle point protecting the footpath and not your home.
 
I am not the OP. My setup captures exactly what I want it to: people on the path walking from the left to the right. I was only giving an example of a simple tripwire in a pitch black scene.

These are not the only cameras I have in this area. The sole job of these is to get captures on the footpath. I don’t care if they come through the trees.
 
Ah Ok. Though that was their picture but it's early. If it's working how you need it to then that's fine. My experience of trips is they're the best but placement can be crucial as you're trying to draw a 2d line in a 3d scene and objects can pass behind if you're not careful.
 
Thanks for the replies. Here is the FOV (the red line is the tripwire) and screenshots of the rules I have setup plus a night shot. As you can see the night image is rubbish so maybe it is getting my camera setting right. I tried straight motion detection and SMD but both give a lot of false alerts. Any help you can give is greatly appreciated.

192.168.1.121_ch_1_20250705_164336.jpg
192.168.1.121_ch_1_20250705_182941.jpg
Screenshot 2025-07-05 171050.jpg
Screenshot 2025-07-05 171115.jpg
Screenshot 2025-07-05 170945.jpg

Thanks again

Mike
 
You have some IR bounce that is impacting the image.

Turn NR down further. Try like 40.

You may need to zoom in more if you can or adjust the camera up a bit if possible to try to get the detection more in the middle.

Maybe try increasing sensitivity as well and try an intrusion box.
 
Wow that was a fast reply. I’m already zoomed fully in, will try your other suggestions tomorrow. The camera is mounted on a soffit (photo below), could that be causing ir problems?

IMG_1587.jpeg
 
Yep that is part of the IR bounce, so pointing the camera higher is a no go.

In an effort to protect it from elements it was installed too far back and you are getting slight bounce off soffit. We have all been there lol. I had to move a few forward.
 
Oh well, live and learn. If I get time tomorrow then I will move it, otherwise it will be next weekend. Will let you know how I get on once it is moved.

Thanks
 
I guess you could first try angling it down to where top of fence is at top of field of view. That might be enough to get the IR bounce off the image.

Looking at it I don't think you really lose anything from the field of view except the trees.
 
Welcome to IPCT fellow Kiwi @Wallop .

While it's dark outside now, have a look to see where the IR lights are on your camera. If it is at the top of your camera or bottom. 850nm is a dull red glow to the human eye, or a purple to a regular phone camera.
IR could be bouncing off this little roof edge lip if the IR is at the top.
1751702402858.png

One trick you can try without relocating the camera is rotating it 180. Physically rotating it within the housing. Then rotate the image in software.
The IR lights tend to be on one side..... but check with your camera. Possibly your camera has low power (wide angle) IR and a separate high-power (wide angle) IR light on it.
1751702226111.png1751702659065.png

Rotating 180 is not a silver bullet at fixing the issue, there can still be some IR glare.
Hopefully it should be enough and saves moving the camera, or putting a spacer above it.