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Video/Audio Security Solution?
IpSo_ asks: "I work for a medium sized company with many locations across Canada. Each of our offices has at least 10 (some up to 50) computers, and are very public places, so they are a quite common target for thieves. (10 computers go "missing" each year on average) We have a Linux server, and high speed Internet in each location. In short we are looking for a cost effective way to install a entire video surveillance system. (remember, this is many different locations, so multiply the cost 15-fold at least) What would be the best way to have several cameras (some with microphones perhaps?) capture video and broadcast it over the Internet? I was thinking something along the lines of those X10 wireless cameras with a video capture card that supports Linux, but it needs to allow for 2-10 cameras. Motion sensing software would be wonderful as well, but not necessary. Any ideas?"
Very nice webcam. It also runs Linux Inside (tm).
You can ftp to it or look at its HTTP port for various formats of pics (10 frames a second updated, single pics, various sizes).
I have plans for something similar myself, but haven't done anything with it yet.
Only drawback is it is an indoor camera. They say don't aim it at the sun or any bright light (such as a halogen light), so it would be easy for a knowledgeable crook to toast it. But this seems a pretty minor concern, and if you download a frame every second or two, you should have some idea who did it.
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See what Scott Adams has to say on this subject:
I'd start with a [x]-camera setup connected to a multiplexer. It's a normal bit of security hardware that condenses [x]-num of video streams into one. Sample with a well-supported TV-card on 1 sec intervals. Jpeg will gime you a few hundred megs a day, but you can condense it greatly based on the input from thermal motion detectors. Most will supply you with a relay connection, you can chain those for a global motion flag. You will be taking a global picture (thanks to the multiplexer). That gets you down to a hundred megs or less in a 9 hour work day. You can either off load them for archival as jpegs, or you can have the server do (some of) the work. Run a mpeg batch compression once a day, or if you're paranoid combine the approaches and offload 'real-time' images AND a daily movie.
Sound is the same ball of wax, except that you could prolly real-time compress. Record the noise[s], add a breif timestamp with Festival, and compress to mono MP3. There's no real way of combining audio streams, but [x]-num low-bitrate mono streams based on motion shouldn't be so bad.
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Reality check: you can just put up the cameras and not even turn them on, their main purpose is just to scare off people. You will get your money's worth that way and have to write no software, although it would be fun make the system.
Another thing, even though this is probably obvious to you, don't set it up so that the video record is archived on a machine that will be stolen. Also, consider the reliability of the internet connection -- can someone disable it by tripping over a wire or running a program to bog it down ? Not that most theives are that smart; they'll be scared of by unworking cameras.
Secondly, the company I work for has done some video surveillence and monitoring projects, and one thing to remember is that the ability to search and index the record is very important. Often it is not clear exactly when the object disappeared (or whatever the event was), and so being able to narrow your search down with cues from doors opening, motion sensors, or other information is very important.
One job we once did was inspired by an institution that had a vehicle stolen, but hiring one of those video-surveilence consulting places which specialized in this sort of thing to fast-forward through four days (it was a long weekend) of tape on several parking lot exits actually cost more than the vehicle was worth, so they didn't bother. If the pictures had been processed to detect motion as they were stored, then it would have been reasonable, if you had software that would let you jump to motion scenes, or do searches such as "show me all exits (not entries) of vehicles in which there were no other vehicle motion in preceeding ten minutes, and happened at night".
If I wanted to steal a monitored computer, I would first turn it off and put a sticky note on it saying it always crashed after it was on for a while (thus people don't mess with it for a couple of days). That way you can't search the video log based on the moment it disappeared from the network. After a couple of days I'd just take it; hopefully I could be alone with it long enough to pop the case open and just grap the HD, RAM, and whatever, and then leave the case there to be discovered empty days/weeks later. Then you have no way of looking at the video record and jumping ahead or backward until you found the moment the machine disappeared.
But the ultimate VSAM (Video Surveilence and Monitoring) system would allow you to search based on the presence of a single person in the room in the area of question for more than X minutes; then you'd nail me.
Check out a review of the Axis cam at Linux weekly news. They liked it alot!!