The good news is that most high quality video analytics systems these days work quite well with IR lighting for night time detection.

The one thing that often gets overlooked, however, is that IR lights attract insects. Apparently they like the light and the heat. And insects often attract bats and birds, and sometimes even spiders, who occasionally spin a nice web across your camera lens to catch the bugs.

When you are just recording video, this only means you might have an annoying bug or bird flitting near the cameras. Not a huge deal.

But with analytics, it can cause false alarms.

I first learned about this many years ago. Our analytics have not had many reports of bug problems, but we’ve seen a few. Then, I ran across a report by Raytheon that summarized years of experience, including deployments in Middle Eastern deserts, proving the problems created by mounting IR illuminators too close to the camera. Their suggestion: Don’t mount IR lights near cameras.

Sounds like a good suggestion to me.

I just searched to see if I could include a link to the Raytheon study, but it doesn’t appear to be on the web any longer. However, I did run across this document:

http://www.dvmd.com/downloads/ApplicationGuide.PDF

This article says:

“The ring of LED’s around the lens of “bullet cameras” attract amazing numbers of flying insects in summer months.”

Bullet cameras with IR LEDs have become quite popular, but I’d suggest avoiding them with analytics. It is better to mount the IR lights away from the cameras and preferrably closer to the area you are trying to illuminate.

The article also makes this comment:

“Bugs can produce approximately a thousand nuisance alarm events per hour…”

We’ve never seen anything like that. In fact, false alarms are rare from bugs with any good analytics technology, but they do occur and so the wise thing is to avoid the issue by mounting the light sources at a distance.

The reason this article describes thousand of false alarms per hour is because they are talking about Video Motion Detection, not Video Analytics. This is just another example of why VMD is not reliable outdoors.

One other thing to keep in mind with nighttime detection: If you are using a day/night camera, you should know that some video analytics technologies have problems when the camera switches from day mode to night mode, or vice versa. When the IR cut filter switches in or out, it creates a sudden change in all the pixels. This can create false alarms for many technologies.

VideoIQ’s technology doesn’t have a problem with this, and I know there are other good video analytics technologies that don’t as well, but some do. So, if this is an application you are working on, you might want to check with your vendor first.

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