I want to make a very simple installation. 

I want to capture the movement of the person with a camera from the ceiling. Next to camera will be a projector. It will project an object which will appear to move to the point of the person.

I know a bit color tracking with RGB dist and pixels commands, and also i tried jmyron. but i dont know how to get the blob position to  determine the position and movement of the  x and y coordinates of the object.

I would be really happy if somebody has an idea.

all the best

Mart