A method and apparatus for tracking an object using one or more video cameras
together
with a plurality of microphones and/or geophones, whereby accurate tracking of
the object can be obtained even when the object changes directions as a result
of an impact. A tennis ball may be tracked during a tennis match. Prior to and
after an impact, the ball is tracked with the use of video cameras, illustratively
in accordance with the method disclosed in U.S. Pat. No. 6,233,007. Then, the position
of the ball at racket or ground impact is accurately determined by measuring the
acoustical waves generated by the ball hitting the racket and/or either the acoustic
waves or the elastic (Rayleigh) waves generated by the ball hitting the ground,
respectively. Tracking then advantageously continues with use of the video cameras.