Rain and Infrared Camera during Night

Question

Currently, I'm suffering from to much events generated by a cam with infrared beam during the night and rain - every raindrop near the cam is causing an event, allthough I have increased the threshold already.
Increasing it mor would lead to insensibility during the day as well.
Q: has some one experience in setting this up properly or may someone give a hint?

Threshold is 1600
Despeckl is eD
gap is 30 secs
minimum frames is 2

Any help appreciated and many thanks.

Environment

Motion version:	3.2.8
ffmpeg version:	0.4.8
Libraries:	ffmpeg
Server OS:	Linux with V4L2

-- AxelAmthor - 26 Feb 2007

Answer

I have a similar problem on my camera 13. A camera showing a bird feeder house. When snow melted I got 1.5 GB of drops.

I do not have a good solution. I get so little snow that I can live with it. But my cameras that are more protected under the roof do not have the problem.

I think a sun screen will help a lot as it prevents drops that are very near the camera to become very large in the picture. They are moving objects and very difficult to filter off from real motion.

If you can limit the number of very near drops having a minimum frames value a little higher may help. But do not make it too high because that hits performance as well. Values up to 5 may be feasible. But you will miss the very short events then.

Despeckle is eD does not do much. You can always try to despeckle more. Or you can run EeD and lower the threshold a little. That will filter off small objects more. But drops very close to the camera or hitting the camera are large objects and impossible to filter off.

-- KennethLavrsen - 26 Feb 2007

Answer

Thanks for your hints. Actually, there is a so called "sun roof" on the cam. But I also got Gigs of drops :-). Apparently, drops or snow are reflecting the infrared light directly back to the cam and therefor they are large and bright moving objects. I'll try with the settings and let you know.

--

I'm having the same issue with "despeckle_filter edl" - I will try with EeD but I tried various combinations and found edl was the one that didn't react to camera noise at night and didn't cause events to be missed during the day. Are there any other suggestions?

-- RomanGaufman - 13 Dec 2008

- Well, I have the same problem (during night) with this camera : http://www.comenzi.ro/product_info.php?cPath=170_173&products_id=1349

- I think the IR LEDs are too many and is situated much closer near the lens of the camera...(also the glass of the camera reflect the IR beam).

- Maybe we must disable those internal IR LEDs and change them with this kind of external IR LED spot : http://www.comenzi.ro/product_info.php?cPath=170_174&products_id=1121