Hi and thank you everyone.
I do have a an adapted Arduino novecento (made by HANGAR.ORG) with a wifly and an accelerometer attached to it, that I used back in 2013. I've also used smartphones with the very simple ANDOSC app (love it). But now I was looking to do this without any other sensor than the camera.
I once saw TRINITY, by Oscar Sol. AFAIK he only used one cenital camera and projector (and strong infrared washers and an IR-reflecting costume on the dancer). He did the magic with MAX-MSP (music made by another guy with other systems). I could not find any video where the rotation analysis is evident, but I remember the feeling it was (maybe I'm wrong). Anyway, here's the link.
@dbini yes a differential analysis is for sure the way to go (thanks for the value delay tip), the thing is, which parameter could I feed in?
Maybe you're all right and I should get the dust off my old arduino and just add it into the data stream. I was just hoping it could be done without it.