2D Tracking in World Space

Since the base of Norfair is a Kalman Filter, can we perform 2D tracking in Euclidean space?
Ie. the (x,y) points being passed in are actually the coordinates in world space rather than image space.

Also, if our robot (frame of reference) is moving, could we just manually define the homography matrix as the transformation matrix?

Thank you in advance!

James
