Patent ID: 6317237
Filing Date: 2001-11-13
Classification: G01H,G01S

Abstract:
A voice monitoring system using laser beam for monitoring voice within a room from an outside of the room, the system comprising:a laser transmitter (100) for irradiating a laser beam (B1) of invisible wavelength band toward a predetermined target (410) to be monitored; anda laser receiver (200) for converting a positional change of a reflected beam (B2) from the target (410) into an electric signal and extracting a voice band component from the electric signal to output it,wherein a beam scanning mechanism (117, 118) for scanning with a laser beam (B1) is provided in the laser transmitter (100) so that a laser spot (Q) formed on the target (410) by irradiation of the laser beam (B1) can be moved within a plane of the target (410).