A portable flight parameter measurement tracks the surface of an object in
motion, e.g., a ball, and determines speed, trajectory, a spin axis, and
a spin rate around that axis. The measurement system is particularly
suited for analyzing the path of a ball in flight which is affected, in
great part, by the amount of spin and the direction of spin imparted to
the ball upon impact. The measurement system provides a user, such as a
golfer, with important feedback for modifying his or her swing to obtain
desired results. The measurement system utilizes non-precision marks,
surface blemishes such as cuts made by a club, dimples, or a combination
of all three as the only features necessary to determine ball flight
characteristics.