Any tips on settings for low light conditions

[ariekanarie]

I am using a Logitech Quickcan Pro 4000 webcam as camera. Although this is a good one for webcams, it obviously does not have the qualities of a professional (security) camera.

I am now trying to setup Zoneminder Modect mode for less then optimal light conditions. Looking at the watch window, the picture is still very clear, but a little noise all through the picture is also visible. I have tried several settings for active zones, but always get contiuous alarms. Example:
Method: Blobs
min. alarmed area: 3
filter width/height: 3
min. filtered area: 3

When I check the stats of an alarmed picture (without anything visable moving in the alarmed area), I usually get something like:
Alarm Px: 84%
Filter Px: 59%
Blob Px: 59%
Blobs: 4
Blob-Sizes: 1-43%

I assume that the noise is causing ZM to detect motion.

Are there any hints or best practices on how to filter this kind of noise?

Using ZM 1.21.0.

[thelight]

I found that using pixels instead of percent for zone settings at least helped me fine tune the motion detection settings for night vision.

[ariekanarie]

Took some more experimenting and thorough reading of the manual: The trick is in the "minimum pixel threshold" setting. Set on 8 I get perfect alarm detection.

I am just a novice on ZM, but I am very impressed with the functionality and user interface. On FC 8 I had little problem installing from sources (although SELinux has to be disabled as long as a working policy is not avaialble). Many compliments to the developers and contributers for a perfect product! I will certainly follow the future developments and contribute if I can.