I have only used motion on the raspberry pi, but it's function is to take a photo or short video when motion is detected. It is a much simpler algorithm than opencv. You can actually use opencv to detect objects and faces. I haven't used it yet, but now have a book on the project and intend to try to get it to recognize members of my family.
I was able to get the omega to stream video pretty easily (there are other threads). It was a pain to get the streaming library compiled on the pi.