Using smartphones' cameras for video surveillance

Question

I have two smartphones that I no longer use and I'd like to use their cameras for a basic video surveillance system, rather than buying expensive cameras.

My idea is to record overnight, and save the videos on my laptop.

It would be a good opportunity for me to learn a bit more about Android programming as well.

So I guess the approach is:

• a TCP/IP server, gathering the information coming from the two (or N) phones;
• a TCP/IP client, to run on each phone, recording and sending the information to the server;

I am not sure what that "information" should be, though. Should that be the single frames captured by the cameras, or is there a way to stream a video?

In case I wanted to implement a basic motion detection, would it be better to do it on the clients or on the server?

Is my approach above correct?

Answer 1

Have a look at the open-source libstreaming project, which will allow you stream video from your phones. But if you want a time-lapse recording, e.g. 1 frame per second or less, then sending single frames may be preferable.

Note that your smartphones will need all-time power supply, because camera and communications will drain any battery in very short time. Also keep in mind that phone cameras do not perform well in low-illumination conditions, and this may justify investment in expensive dedicated cameras.

You can use OpenCV for motion detection either on device or on server, or even both. The choice depends on your needs and resources. E.g. you may significantly reduce overall data volumes if the device only send the video when it detects motion.