Lightning triggers my zone - I thought I had that covered

Discussions related to the 1.36.x series of ZoneMinder
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lyallp
Posts: 137
Joined: Fri Nov 26, 2010 2:36 am
Location: Adelaide, Australia

Lightning triggers my zone - I thought I had that covered

Post by lyallp »

We had a thunderstorm today and ZoneMinder fired off an event on a lightning flash.
The event had two alarm images, the first of which I have shown here.
2/3 of second later, another lightning flash, which also alarmed. (12 frames).
Both within the same event.

Note, in the screen capture, below, I have shown the details of 3 frames in a row, the 2nd of which is the alarm frame.

(NOTE: I had the Pixel Min/Max set to 20 at the time, unlike what shows in the image. I am fiddling with events firing off and am in the process of testing the sensitivity of pixel change, it just was not working as expected at 20, not detecting half a human body, only detecting their shirt, for example).

The frame each side has a score of 0.

I figured I had lightning covered by having Overload Frame Count set to 10 on the Zone definition. 10, because I have seen the camera 'refocus' and I thought I would try covering that.

I could understand an event firing off if there where 10 consecutive images which showed the lightning, but this is not the case. It is only one. (and another one about 2/3 seconds later (12 frames) at 30 frames per second)
Lightning Flash-Zone Defn.jpg
Lightning Flash-Zone Defn.jpg (87.4 KiB) Viewed 687 times
Lightning Flash.jpg
Lightning Flash.jpg (90.84 KiB) Viewed 687 times
...Lyall
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lyallp
Posts: 137
Joined: Fri Nov 26, 2010 2:36 am
Location: Adelaide, Australia

Re: Lightning triggers my zone - I thought I had that covered

Post by lyallp »

Sort of worked around this, can't really say problem is solved, as lightning doesn't happen that often.
However, my e-mailing concurrent and background filter, simply said, only send if more than 50 alarm frames (30 fps camera).
Seems to do the job, not crowding my mailbox.
I setup another background filter to delete events with 50 or less alarm frames.
That seems to keep the number of events down, in ZoneMinder.
...Lyall
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Andyrh
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Re: Lightning triggers my zone - I thought I had that covered

Post by Andyrh »

I think you are looking for min/max alarmed area, set the max to less that the whole zone.
Andy
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lyallp
Posts: 137
Joined: Fri Nov 26, 2010 2:36 am
Location: Adelaide, Australia

Re: Lightning triggers my zone - I thought I had that covered

Post by lyallp »

Curiously, lightning only triggered a blob on a small part of the whole picture, primarily a reflection off the wet ground.

So far, I have not managed to get a significant area to be alarmed, so I feel that the max alarm area really doesn't come in to my triggering.

My issue was that it was a single frame which triggered the event (well, 2 frames, separated by 12 frames), which, whilst I have not prevented the triggering of the event, I have sorted with regard to building up huge numbers of insignificant events.
...Lyall
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