Patent US 5,239,463

An improved video system that enables a player to interact with mid-air stereo perception images of foreshortened perspective animation and return the animation back to the playing field on the projection screen or monitor, or to effect other interactive dramatics with the animation. The improvements include placing an ultrasonic transducer on the player's body for allowing the player's position to be calculated and providing the player with a pair of glasses that improve 3-D viewing of the animation. The animation reacts according to the movement of an instrument such as a baseball bat, a tennis racket or a rifle controlled by the player, as well as to the speed and direction of the player's body movement. The relative positions of the player's body, the instrument and the animation are tracked with an array of point microphones that receive signals from the ultrasonic transducers.