Anchoring Video to a real point on stage

I'm wondering if jitter can do this or the hardware I would need to get this going.

I have an actor on stage. In front of him is a camera and a projector- both stationary. As the actor moves around I need a fixed point that software can acquire then use as a relative anchor point for video clips.

In practice you could use this center projected patterns on the actor or project objects that track along with movement. I would be happy with XY tracking.

If there is a proper term for this set-up I would be happy to read up on it.

Thanks for any help!