Alarm When it is Getting Dark

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coinageboy
Posts: 17
Joined: Sun May 27, 2012 1:06 am

Alarm When it is Getting Dark

Post by coinageboy » Sat Jun 16, 2012 5:48 pm

AXIS 211A, in an external enclosure.

When it is getting dark, Zoneminder shows alarm for an hour or so.

It seems to trigger on some compression artifact - the picture shows shimmering grains when it its getting dark.

Tried both MJPEG and MPEG 4 - same outcome.

I could possibly detune the alarm trigerring but it is not all that satisfactory as it is (sometimes 'misses' a person walking slow, wearing gray clothes).

coinageboy
Posts: 17
Joined: Sun May 27, 2012 1:06 am

Re: Alarm When it is Getting Dark

Post by coinageboy » Sun Jun 17, 2012 4:57 am

Actually, I have found an interesting solution (hack).

I have noticed that the automatic motion-activated outdoor halogen lamps ($35) do a decent job detecting motion and do not respond to moving tree shadows, video artifacts, Etc..

Also, the sensor works even during the day when the lights don't get activated.

So I took apart the sensor and connected a resistor and an optocoupler to the sensor's indicator LED. Connected the optocoupler output to the AXIS camera digital input and set up a notification to the zmtrigger.pl.

Very agile, no false alarms, I am very pleased with the outcome and will consider this mod for some more of my outdoor AXIS cameras.

Augustine Lehecka

mitch
Posts: 169
Joined: Thu Apr 30, 2009 4:18 am

Re: Alarm When it is Getting Dark

Post by mitch » Mon Jun 18, 2012 3:48 am

Certainly an innovative hack. If you wanted to fix the problem in ZM there are a few things to try:

1) If its darastic quick changes you can try to just set the overload count to 1-3 frames so the motion has to continue for more than just a frame
2) If its the entire picture pixels are just changing slowly frame to frame generally upping the minimum diff will solve this issue
3) If its massive swings that 1 & 2 cant solve you could look at a max pixel limiting or if the camera covers a zone that never would have activity make it an inactive zone to exclude out the alarm if there is motion there.

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