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Extend Alarm Frame Count - explanation?

Posted: Fri Nov 07, 2014 1:33 am
by Jamo
Hi

Can anyone tell me the purpose of the above field - "Extend Alarm Frame Count" in the zone setup? It is the first time I've noticed it - not sure if it was introduced in 1.27 or 1.28.

Just curious and hoping to understand more for configuring my zones.

thanks for the great software.

James

Re: Extend Alarm Frame Count - explanation?

Posted: Fri Nov 07, 2014 4:35 pm
by knight-of-ni
That field is for Preclusive Zones only.

What it does is allow you to keep the Preclusive Zone active longer than just 1 frame.

Here is how the original author describes it:
Here's the problem I'm trying to solve: After sudden change in lighting, my cameras tak a few moments to adjust auto-exposure. Combined with gradual image blending, I end up with a slowly shrinking alarmed area that will result in a false alarm.
I can easily define a preclusive zone that will trigger on the change in lighting, but I need to keep the preclusive alarm active for a couple of frames to avoid the false alarms.
You can read all the details here:
https://github.com/ZoneMinder/ZoneMinder/pull/338

Re: Extend Alarm Frame Count - explanation?

Posted: Wed Nov 26, 2014 11:52 am
by Jamo
Awesome, thank you for the feedback - that could prove useful to me in tuning my motion detection.