Taking a stab at understanding zone settings...

[snakebyte]

So I've been tweaking my zone settings and managed to screw things up enough so that now it doesn't detect anything anymore.. haha.. anyway, I thought I'd give an example of two zone settings that I've got going and explain what I think the numbers mean with the hopes that someone will correct my misunderstanding.

The first zone is a Preclusive type. I understand this to mean that if it ever triggers (and passes the alarm check method) that any other alarm that might also trigger at the same time will be ignored. I use this for when clouds and fog roll past the sun causing great changes in brightness for the entire monitor... it's also used at night to ignore the headlights of cars that drive past the street.

I'm using Percent for the units. I'ts just a small box.. 5,5 to 15,15.

Alarm check method is set to "AlarmedPixels". This is the simplist method which doesn't use filters or blobs.

Minimum pixel threshold is 5 and maximum is 255. I'm not certain how sensitive this is, and it may be TOO sensitive... This is hard to tell though since because there is no feedback, I can't tell if the system is truely idle or if it is actually actively ignoring (which means that nothing else can trigger even if it wanted to).

Minimum alarmed area is 80 and maximum alarmed area is 100. I'm confused as to whether or not this means 80 to 100 percent of the entire monitor or 80 to 100 percent of the zone, or of all the zones combined... Intuitively I believe this is only for the zone itself.


The second zone is what I use to trigger events.. If there is motion here, like someone walking by, I want to record the event.

Type is Active
Units are also in percentages.
size of rectangle is 0,65 to 45,100

Alarm check method is Blobs. This means that a series of tests are done after the initial trigger... first, it goes through the pixel threshold, then the filter, and finally through the blob checking.

I've got the minimum pixel threshold set to 25 and the max set to 255.

The minimum alarmed area is 5 and the max is 80. I assume this means 5 percent to 80 percent of this zone must be different in order to trigger the event.

Filter width and height are both blank... I don't want anything to go through an additional filter.

Filter area is 5 to 80
Block area is also 5 to 80

The idea here is that if all of these settings (alarm, filter, and blob) are the same, there shouldn't be any more restrictions besides what I've got set with the blobs.

Minimum blobs = 1 and maximum blobs = 50... this is a total guess.. I have no idea what is normal for a person or dog or a bird to go through the zone.. I would assume that any of those would show as one blob, but I wanted make sure that the zone didn't miss anything so I made the maximum 50 hoping that it would still ignore things like the grass moving.

Anyway, with those two zone, I get no events... so obviously something that i've done is wrong. Any clues?

Also, is there any chance that when we turn on the ZM_CREATE_ANALYSIS_IMAGES or ZM_RECORD_DIAG_IMAGES flags that it also include some real numbers that relate to these zone settings? Things like percent of the zone that triggered, the number of blobs, and the actual minimum and maximum pixel threshold of the event would help weed out the events not wanted.

Thanks!

[zoneminder]

Hi,

You're pretty much on the right lines here. The only thing I would suggest is to set the filter width to 3x3 as with no filter you actually get no pixels surviving it (this may be a bug!).

The other thing is, if you turn on RECORD_EVENT_STATS you should get a stats link up whenever you are viewing an alarm frame from an event either as the image or from the frames listing. This has some of the information you've asked for and so may help.

Phil

[snakebyte]

Took me a while to find where that stats link is. For anyone who wants to check this feature out:
Click on the Event. Choose Stills, Click on the still with motion (There should be a red border around the frame), and finally you'll see the "stats" link next to the frame number. That link should bring up a popup with the important data.

[zoneminder]

The frames listing is also available from the events list if you click on the score column (I think). Then if you click on any alarm frame you'll go to the stats pages as well.

Phil