I have a DS-2CD2385G1-I Network EXIR Turret Camera with only an alarm configured for a 'line crossing'. It is set at 85% sensitivity but it still alarms when a shadow is cast across the line, which I would like to reduce. I would ideally like the sensitivity to be higher otherwise it can miss pedestrians crossing the line. Can anyone advise on how I can reduce the number of false alarms?
How can I minimise alerts caused by sun/shadow across line-crossing?
- Thread starter Photoscot
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The 85 applies inversely to the percentage of a target object crossing the line. So at 85, only 15% of the object has to cross your line. Shadows are difficult to deal with depending on the orientation of the camera view in relation to the sun. For best results:
- Set up the minimum and maximum object sizes. If you're looking on an NVR that might not be available (depending on model and firmware of NVR). If that's the case login to the cameras menu directly and you will find the option there. You want to be setting the minimum size box slightly smaller than a human and the maximum size bigger. Have someone stand on the line while you draw the box if necessary as it's not always obvious how large a human will appear on the screen at the point of line crossing.
- Set the direction A>B, B>A, A<>B. If you're only interested in people entering your property across the line, it's pointless having it set A<>B as you're going to double the amount of false alerts potentially.
- Experiment with the sensitivity. If you've set the minimum and maximum target sizes, there should be no need to have the sensitivity high - if someone hasn't crossed the line you don't need the alert.
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