ZoneMinder Forums

I have my USB webcam working quite nicely with a motion detection trigger.
I have my camera pointing at an area where people walk past and am only interested in those that stop.
I have noted that people that stop cause more than 5 'alarm' frames
So, I would really like to say 'do not trigger if under 5 alarm frames'.
Can I do this?

Hi,

What if you create a filter that deletes the events with less than 5 alarm frames?.

Hope it helps,

PacoLM

Looks like I need to RTFM regarding filters...

Thanks

Set alarm frame count to 5.

Ok, Filters, great, that worked real well.

bb99: Awesome, I finally found that by clicking on the source URL. I also found it by checking the mark checkbox on the right and clicking edit.
This will solve another one of my problems whereby I was triggering due to lights going on and off during the night.

Thanks to both of you.

Maybe a better answer for the lights? Click on the zone for the monitor you are having an issue with (7th column to the right on main page), single click on the zone you want to adjust (most times "all"), change the value of "Overload Frame Ignore Count" to a value that eliminates the lighting issue; I use 4 or 4 tenths of a second at 10 fps. Pretty much does the same thing but allows alarms (recording) if the monitor is not overloaded, the other is not selective, takes 4 frames in a row no matter what.

Thanks for the overload suggestion, will find out if that works tonight
I should point out that the Overload Frame Ignore Count setting is not documented anywhere.
What does it mean? How does ZM decide that a zone is overloaded? I assume it's meaning is that the Zone has decided that more than the max area of the zone has activity, that the zone is therefore overloaded and if this field is set, then we ignore up to 4 overloaded frames (in this case), after which, we treat the zone as having alarmed?

Slight variation on my original question.

I have set my 'source -> buffers -> Alarm Frame Count' to 30.
However, I am still reporting alarms with an alarm frame count of 17.

My monitor settings are
Image Buffer Size (Frames) : 90
Warmup Frames : 25
Pre Event Image Count : 5
Post Event Image Count : 5
Stream Replay Image Buffer: 2000 (actually, I have no idea what this does, I haven't found any docs on it)
Alarm Frame Count : 30

My zone is set to "Best, High Sensitivity" preset, other than the now changed Overload Frame Ignore Count.

Using ZoneAlarm 1.24.4 on Gentoo x86 Linux with a USB webcam (MSI StarCam 370i)

Any suggestions?

From the docs:

Alarm Frame Count
This option allows you to specify how many consecutive alarm frames must occur before an alarm event is generated. The usual, and default, value is 1 which implies that any alarm frame will cause or participate in an event. You can enter any value up to 16 here to eliminate bogus events caused perhaps by screen flickers or other transients. Values over 3 or 4 are unlikely to be useful however. Please note that if you have statistics recording enabled then currently statistics are not recorded for the first ‘Alarm Frame Count’-1 frames of an event. So if you set this value to 5 then the first 4 frames will be missing statistics whereas the more usual value of 1 will ensure that all alarm frames have statistics recorded.

So you nailed the max value dead on.

Sigh.
I didn't realise there was a limit on the alarm frame count.
Basically, I have an area that people walk past. I only want to alarm when people stop.
I have my pre-alarm FPS at 10, to keep CPU usage down, but during alarms I want as many frames as I can get so I increased my alarm frame rate to max. Problem is, it takes more than 16 frames for them to traverse the zone.
Maybe I will try shrinking the zone horizontally...

Or slow down your "Maximum FPS" (pre alarm) slower as in 5 fps. You should then get 3 seconds before alarm trigger and the higher frame rate. Adjust zone? That'll work too, just limit where, side to side, ZM is looking

I was hoping I could record the event at max fps.
I still hope.
Narrowing the zone seems to have helped.
I am also fiddling with preclusive zones that will alarm at 1 frame (whoops, frame alarm settings are at the camera level, not the zone, still...), they may prevent walkby alarms and to catch lights going on/off.
More fiddling is required.

I'm suggesting slowing down the "Maximum FPS" (pre alarm) only; keep the "Alarm Maximum FPS" (post alarm) at 30 or whatever you've currently set. That way you're analysing 5 fps normal but recording alarms at 30 fps. At 5 fps you should have 3 seconds of "Alarm Frame Count" before triggering the alarm and then recording at 30 fps during the alarm. Am I making any sense? Does work.