False alarms when the lights goes out (Cam IR light)

[dkw7]

I have a camera placed in a dark lobby to monitor entering/leaving the room. In the lobby there is lighting that is activated by a photo cell as a result of which I get a lot of false alarms when the lamp goes out and the IR light from the camera is activated (attached video).

I played a lot with the settings of the zone (Min/Max Pixel Threshold and Overload Frame Ignore Count), but I could not achieve a result so that the alarm is not activated when the lights go out. Any guidelines?

Event-video sample - https://vimeo.com/692996740

[haus]

You might be able to turn on analysis images (with the red outlines over motion detected) and tweak your settings. I have situations where the "motion" detected is roughly person-sized, so without more intelligent object detection there's no way to distinguish between something vaguely person sized and a person. In your case it seems like the light switching should definitely trigger an overload situation and should be fairly easy to work around.

Looking at your screen shot, you didn't define a max pixel threshold, which might be your issue? I think you have to have a pixel change above that in order to trigger an overload, and maybe it doesn't like it if the max value (0) is lower than the min value (40)? Try setting the min to 20 and the max to 50 or something like that, then look at the analysis images to see what ZM "sees" as motion when the lights change.

[knight-of-ni]

You almost have it. You need to modify both the overload frame ignore count and the extend alarm frame count.

[haus]

Isn't extend alarm frame count for preclusive zones only? This looks like OP is trying to set an overload threshold for an active zone so that too much change doesn't trigger an alarm.

[patmansf]

You should post a video of what you want to capture too, we can't tell if this is where the motion is expected or if this is where no motion is expected.

But, it looks like you should make this a type "preclusive" or add a preclusive zone.

Select an area where you expect no motion, and set it up so if most of the area has pixel changes like you get with a light going on or off, then nothing is captured - you want to set the minimum for the "Min/Max Alarmed Area" to something like 50% of all the pixels in the zone.

And then you might be able to use the "Extend Alarm Frame Count".

Read:

https://zoneminder.readthedocs.io/en/la ... ezone.html