C# multiple object motion tracking with x,y cordinates streaming to port.

I need a motion tracking class/app/dll which accurately tracks multiple objects using a web cam, each object must have a central point and its coordinates calibrated to the flat surface streamed to a port using TCP/IP. The flat surface (a floor/wall) surface may be a A4 paper or a large mat; the user will set the bounds of the flat surface, and based on this any objects like a foot a hand must be tracked and coordinates streamed asynchronously to a port.