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Trigger Zone Alarm after a few seconds of detection

Posted: Wed Aug 29, 2012 6:04 am
by McFuzz
Hi all!

A surveillance n00b here who learned about Zoneminder and set it up only yesterday!

I have a specific motion zone configured which works great during the day.. but for night-time, alarms are sometimes triggered by passing headlights which spill over into the zone, as well as occasional flickering.

I am trying to figure out if there is a way to trigger recording of an alarm only if it detects continuous motion for say 8 seconds at which case I'd like it to include the 10 seconds before motion detected and 10 seconds after motion detected (which I understand I can adjust via frame buffering).

Can someone please point me to how I can create such delay?

Thanks!

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Wed Aug 29, 2012 7:00 am
by Christo
McFuzz wrote:Hi all!

A surveillance n00b here who learned about Zoneminder and set it up only yesterday!

I have a specific motion zone configured which works great during the day.. but for night-time, alarms are sometimes triggered by passing headlights which spill over into the zone, as well as occasional flickering.

I am trying to figure out if there is a way to trigger recording of an alarm only if it detects continuous motion for say 8 seconds at which case I'd like it to include the 10 seconds before motion detected and 10 seconds after motion detected (which I understand I can adjust via frame buffering).

Can someone please point me to how I can create such delay?

Thanks!
Hello McFuzz,

First of all, you have to look into the recorded data to get the duration of these (occasional) events.
You should look for the amount of continuous alarmframes (without pré / post event).

This amount of frames can be set to the "Alarm Frame Count" (see monitor Source; Tab "buffers"
Or.. you could just try to increase this amount and have some luck!!

Goodluck and regards, Christo

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Wed Aug 29, 2012 2:16 pm
by McFuzz
Hi Cristo,

I think you are on to something here... I totally missed that field! These events last for a frame or so; a flicker here, a camera color blip there... I'll play with it and give it a test.

Thanks!

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Wed Aug 29, 2012 9:32 pm
by Christo
Hello McFuzz,

Glad I could help!!

But did forget to tell you that these (occasional) events could also cause a so called "Frame Overload".
In that case, there are NO "Stats" available, in these cases you should play with the the Zone settings as well!!
(see Overload Frame Ignore Count #).

These fields are standard set to zero (0) but must be used to get rid of these disturbing "Frame Overloads".

So, if these (occasional) events have NO "Stats", I suggest to start with "1" and give it a go!!

Goodluck and regards, Christo

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Wed Aug 29, 2012 11:15 pm
by McFuzz
I'm a bit confused... what does 'Overload Frame Ignore Count' exactly do? Can you provide an example please?

Thanks!

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Thu Aug 30, 2012 6:10 am
by Christo
Hello McFuzz,

I think it's not that confusing!!

A "Frame Overload" happens when for example passing 'carheadlights' trigger your detection zone(s) and cause a pixel disturbance larger than your detectionzone(s) settings.
In these cases, you can use the "Overload Frame Ignore Count" to make sure that a number of frames are ignored and do not set of an alarm event.

The "Alarm Frame Count" settings however, are used to get rid of sudden disturbances that causes a pixel disturbance less than or equal to the pixel disturbance settings of your detectionzone(s).


I hope this will explain how and when to use / apply these settings!?

Goodluck and regards, Christo

Re: Trigger Zone Alarm after a few seconds of detection

Posted: Sat Sep 01, 2012 1:46 am
by McFuzz
Ahhh! Got it :)

I think I got it configured the way I want... thought I will be getting a new camera soon enough so chances are I will have to redo the zone, but at least I now have a pretty good understanding of things!

Thanks again :)