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Modetect, zones and load

Posted: Wed Jan 19, 2005 6:20 pm
by Eklectick
Hi Phil

Would the use of a smaller zone to analyze during modetect lighten the load on the CPU?

Would it be safe to say that using 50% of the area instead of the default 100% of the picture being analyzed, render a 50% drop in load?

Regards!

Posted: Wed Jan 19, 2005 7:33 pm
by zoneminder
Yes, that is correct. Also the motion detection is a series of analyses with a yes/no result, so how much CPU it takes depends on how far down the chain it goes. There is a guide I wrote on the forum somewhere that goes into a bit more detail. I'll see if I can find it.

The other thing is, you can switch off the more intensive checks such as blob detection if you like and just have it trigger on alarmed pixels for instance.

Phil

Posted: Wed Jan 19, 2005 8:51 pm
by Eklectick
Phil

Would setting two zones of 50% on the same camera, load the CPU the same as one zone at 100%?

My question would really be:

If I set three zones, one at 25%, another at 10% and another at say 15%, on the same camera (to cover different places) render the same load as of to a single setting of 50%? Or would each zone added move a little overhead rendering something above 50%?

Phil, thanks for your fast replys :-)

Regards!

Posted: Wed Jan 19, 2005 10:59 pm
by zoneminder
There would be a tiny extra bit of overhead but as long as the zones didn't overlap I doubt you'd notice it. Also as each zone would have it's own thresholds you could find that one or more zones drop out with no alarm detected while the third detects one. In that case then only this zone would go through all the analysis so you may save a bit of time there.

Phil