Hi:
Sorry for the delay in reply. The hardware I'm using is MiniDV cameras with a custom synchronization unit. I use JVC and Canon camcorders, and the JVC camcorders cost $330 apiece. You could probably make a mocap rig with 4 cameras for body motion capture in a capture area 3 meters on a side. You could alternatively use USB cameras, but would probably require a separate computer for each 1 or 2 USB cameras. The USB cameras would need a more elaborate custom synchronization device than DV camcorders. The NaturalPoint OptiTrack cameras are $200 apiece when you buy them 3 at a time. All in all, you could build a basic rig (if you already own a computer) for less than a single normal mocap camera would cost.
The issue of mocap quality would need to be quantified to be meaningful. Numbers like positional error ranges and marker occlusion would be good starting points. It also depends on the type of motion being captured. A slow, ambling walk is much easier to capture than martial arts or medical motion capture. The best part of building your own system is that you can select which features to concentrate on. Just remember your basic design rule to decide which two of the following three criteria you want - good, fast, cheap. I.E. if you want it good and cheap, it won't run fast or develop quickly. If you want quick development of a fast (real-time) system, it won't be cheap. I've assumed most of us can't afford to buy a mocap system, so it's either cheap&good or cheap&fast, but not both. So, for my rig, I've decided that I will have slow development of a non-realtime system that requires time consuming calibrations.
Cheers,
Michael
