ZoneMinder Forums

I have two questions of the type "can I do this" or "what is the best way to do that" and one regarding zoneminder's behaviour with captured events. Hopefully someone can nudge me in the right directions.

External image grab
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Is there any way to retrieve from zm the image at which it is looking for a particular monitor? I would like to be able to view samples of the feed through a separate web interface. My thought is that by taking the image from zm rather than directly from the camera I might stress the camera (and network for remote cameras) less so reducing the amount by which the frame rate was diminished. Alternatively can anyone reccomend a simple command line program not requiring xawtv and allsorts of stuff (the machine has no GUI and I want to keep it that way) which I can use to grab images from a V4L device to which zmc is also connected?


Event activated triggers
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I have found quite a lot of information about triggering cameras on external events, but is there a way to get an event on a monitor to create a trigger? The reason for this is that I want events in the active area of a camera with a good overall view to trigger recording by other cameras. The other cameras in question look straight across my property at the road and would left to their own devices end up recording events every time a car/person went past, but they will get a much better view of anyone standing in front of them.


Hollow/disappearing people
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I have noticed that when someone walks across my drive to my front door the ZM event generated shows them initially and then they vanish about half way to the house. The apparrent frame rate from the previous images suggests that there should be several more frames showing them and sometimes I even find that ZM has drawn a red line around the outline of a person but there is no person there, only the ground behind them. I did wonder whether there were a lot of ghostly happenings going on around my house but having seen this happen to me I suspect it is something to do with the processing. Is this a known issue and is there a way round it?

Many thanks in advance,

Adrian

External image grab
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Yes this is possible in several ways.
Via url like so:
http://192.168.10.20/cgi-bin/zm/zms?mod ... &scale=100

Event activated triggers
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I know we have discused it but I don't recal if any thing was implemented or not.


Hollow/disappearing people
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This only happens to the analysed images when you have ZM_CREATE_ANALYSIS_IMAGES (Whether to create analysed alarm images with motion outlined) checked.
The actual captures are not affected.

Regards,
Cordel

ajl199 wrote:Event activated triggers
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I have found quite a lot of information about triggering cameras on external events, but is there a way to get an event on a monitor to create a trigger? The reason for this is that I want events in the active area of a camera with a good overall view to trigger recording by other cameras. The other cameras in question look straight across my property at the road and would left to their own devices end up recording events every time a car/person went past, but they will get a much better view of anyone standing in front of them.

This is not easily supported at the moment. In a version or two, monitors will be able to trigger other monitors to achieve this effect. Unless you have X10 then this would require some scripting.

ajl199 wrote:Hollow/disappearing people
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I have noticed that when someone walks across my drive to my front door the ZM event generated shows them initially and then they vanish about half way to the house. The apparrent frame rate from the previous images suggests that there should be several more frames showing them and sometimes I even find that ZM has drawn a red line around the outline of a person but there is no person there, only the ground behind them. I did wonder whether there were a lot of ghostly happenings going on around my house but having seen this happen to me I suspect it is something to do with the processing. Is this a known issue and is there a way round it?

I suspect this issue is because you may have a high reference image blend %ge. If this is the case then a person (or whatever) gets amalgamated with the background reference image quite quickly and effectively 'part of the scenery'. When they move the part of the image that has changed is person shaped even though a person is no longer in the frame. You could try dropping the ref blend %ge to a lower value to make the background more persistent.

Phil

Thanks for the information. I would like to take this opportunity to say that as and when triggering by events is implemented I think it will be a great feature. Not only would it be good to trigger other cameras but also potentially hardware devices could be thus controlled. For instance an IR camera with an IR illuminator could cause a security light to be switched on only if someone was actually on the property, usually the boundaries of sensors for such lights are much more difficult to set.

I'm still unsure about the cause of the hollow people. Sorry if I misunderstand you but I am sure that the frames shown should display someone in them, this is largely on the basis of the number of frames they are taking to cover a given distance before vanishing and the distance remaining between the frame where they vanish and the end of the camera's view. Also, the red outline typically appears several frames on from where the person dissappeared and in a geographically removed position.

I tried looking at the current picture via a web browser, in my case at:
http://....../cgi-bin/zms?mode=single&monitor=5&scale=100
but I get an Apache "internal server error" which in the logs displays as "premature end of script headers". I expect that this is me being stupid about something but does anyone have any ideas?

Many thanks again,

Adrian

I have investigated and discovered that to access the image via zms I need to add to the parameter list: '&auth=' followed by the string copied out from the image location when I look at the monitor in ZM's control panel.

This only works from the same machine (and possibly same browser? I suspect it's cookie based?) that I used to log into the control panel.

What I want to do is have a script on the server which can retrieve a still image from zms and display it as part of a web page when requested to do so. How should I be going about this?

Thanks,

Adrian

remove the &auth and use
&user=<validusername>&pass=<password>