Apparatus for projecting and moving a spot of light in a scene projected on a screen and for controlling operation of a stepper motor used therewith

摘要

Apparatus for projecting selected images of a scene onto a screen, such as images of a golf course looking toward a green, and for projecting and moving a spot of light on the screen superimposed on the scene, such as to represent the travel of a hit golf ball toward the green in the scene, provides both a scene projector and a light spot projector secured in fixed relationship in the same housing and provides dedicated control circuitry for controlling the apparatus in response to instruction signals received from outside the apparatus. The spot projector includes two rotatable mirrors controlled by two stepper motors to control the movement of the spot on the screen. Special circuitry is provided to generate control signal pulses for the stepper motors using a combination of a count signal pulse and a synchronizing pulse. Compensation for nonlinearities in the stepper motors may be provided by reference to a correlation table stored in memory. The scene projector may be provided with automatic focus control using a modulated light beam and stepper motor position control.