ZoneMinder Forums

Sorry to sound like an idiot, but I don't understand about 20% of the instructions on the wiki. For instance:

"Min/Maximum Pixel Threshold
These setting are used to define limits for the difference in value between a pixel and its predecessor in the reference image. For greyscale images this is simple but for colour images the colours are averaged first, originally this used an RMS (root mean squared) algorithm but calculating square roots mugs performance and does not seem to improve detection. Using an average means that subtle colour changes without any brightness change may go undetected but this is not the normal circumstance. There is also the option to use a more sophisticated integer algorithm to calculate a Y (or brightness) value from the colours themselves. "

Huh?

I am just using a preset called Fast/Sensitive and it seems to work. I have no clue what numbers to put where or what they are supposed to do.

I'm not even sure what the difference between Fast and Best are. I just know Best doesn't set off alarms at all unless I stand in front of the camera and wave my arms.

So, are there instructions anywhere for people who know nothing about A/V and cameras?

Min/Maximum Pixel Threshold
These setting are used to define limits for the difference in value between a pixel and its predecessor in the reference image. For greyscale images this is simple but for colour images the colours are averaged first, originally this used an RMS (root mean squared) algorithm but calculating square roots mugs performance and does not seem to improve detection. Using an average means that subtle colour changes without any brightness change may go undetected but this is not the normal circumstance. There is also the option to use a more sophisticated integer algorithm to calculate a Y (or brightness) value from the colours themselves. "

Visualise breaking the image into a grid each box is a pixel

Now if you have two images and they are the same except one has a bird in it

Now if you break those up into grids so each box is one colour

there would be some boxes that differ in colour between the two

now lets say you have 10 changed boxes

now remember there are shades in colour red to purple to blue etc.

so if those 10 boxes changes by 30 shades

and zm was set with a threshold of 30 or less it would alarm


Does This Help


And now what makes the Best pre-set is it uses and average of say 4 boxes then compares

Thanks for the help.

I don't understand why the Wiki instructions don't say anything about how to actually run Zoneminder. When I get away from it for awhile I forget how I logged in via the webpage. Sometimes you really need to have some simple instructions like "type this in the address bar to configure Zoneminder."

I now smile when I see a comment like this:

I don't understand why the Wiki instructions don't say anything about how to actually run Zoneminder.

Not picking on you, and I had the same questions/thoughts when I first started playing with Zoneminder.

However I now understand that Zoneminder isn't a program like Word or Excel, or even KWrite that we can just click and run. It is a server that runs in the background. We can see what it is doing by using a Browser and connecting to a web page.

And in the Wiki it says this:

If you are running a distribution which doesn’t support the zm script, or if you just prefer more direct control, you can now start ZoneMinder by typing

zmpkg.pl start

which, after a few seconds, should return without error. You can subsequently stop and restart everything by changing the ‘start’ parameter to ‘stop’ or ‘restart’.

Now fire up your web browser, point it at your zm.php and off you go.

That seems pretty clear to me. The only thing a newbe should have trouble with, is realizing that the statment "fire up your web browser, point it at your zm.php" really means enter the address "http://localhost/zm" in your browser address window.

Once you have that page open you can make a bookmark. Then you can start/stop the server; add/delete monitors; view events, and basically run the whole thing...

Hope that helps, Keith

Yeah, I had to spend quite some time searching the Internet to find another poor newbie who had the same question, "How do I run this thing?"

It can be difficult to wade through instructions sometimes. They give you a history of the development, talk about how wonderful their application is, blah blah about all the services and scripts they wrote, then skip whole concepts because it all seems so clear and simple to them; why mention it?

If you look at the Arch Linux wiki, it's clear and concise. They have some of the best instructions anywhere:

1. Install ZoneMinder
2. Open your browser
3. Type http://localhost/zm
4. Configure ZoneMinder

Once you have that simple concept you can now play with all those wonderful settings the developer worked so hard on. When you find out how awesome ZoneMinder is, then you might even want to read the history of it's development because they did such a good job on it.

The blurb about "zmpkg.pl start" is halfway through the compilation process, which I skipped because I installed it from the Ubuntu repository and didn't have to compile anything.

Anyway, I'm not complaining. I appreciate the help, and ZM is awesome now that I have it running. I just like to get developers and instruction writers to see how it looks from the beginner's perspective. Start with baby steps and add complexity as it's needed. Too much complexity at the start just causes frustration.

Thanks again for all your help, and thanks to the ZM team; awesome program.

Your assuming that we have a whole team where as we do not. It's mostly a one man show with a few people contributing help when available. Also everything is kept generic because installations will vary dependent on the options you install with, so while some one could write more concise documentation, they would have to be specific to the distribution beginning with how it was installed for locations and options all the way to the end and would only be specific to that install. The packagers for the different distro each create their own scripts which varies the way things work as well.

While we try to keep things generic enough, others that have access to the wiki do not typically pay attention to the above which creates yet more confusion.

I certainly agree that documentation for the web console which is constant could be better documented, and the available commands are in the documentation and current detail can be had with [command] --help, though I have not seen many volunteers to maintain documentation or anyone well suited for the job really.

If anyone does want to volunteer, I am sure we can work something out. The wiki has become sort of a mess.

Well, if I ever get a chance to retire, I'll give it a shot.

Anyhoo, the program is doing a great job. I have seen software like this that didn't look nearly sophisticated running for around $1500.00. Really good job on the software. Open-source projects amaze me.