DEVICE FOR OBTAINING UNDERWATER VIDEO IMAGE AND ACQUISITION METHOD

PROBLEM TO BE SOLVED: To obtain a clear underwater acoustic image by reducing the volume of data of reception signals, enabling reduction of the scale of an electronic circuit and the size of a device, and suppressing noise and harmonic components. SOLUTION: The device for obtaining an underwater video image includes an acoustic lens on a front face of a wave receiving unit, for steering a transmission beam of a sound wave emitted from a wave transmission unit 104 in a horizontal or perpendicular direction by changing the frequency of an electric signal to be input to the wave transmission unit 104, and for converging a reflected sound wave from a target. The wave receiving unit is configured by a plurality of wave receiving elements 105 divided in the direction perpendicular to the steering direction of the wave transmission unit 104, and includes: a plurality of active mixers 107 for down-converted received signals from the wave receiving elements to those of a predetermined frequency by multiplying two signals of each reflected signal (received signal) received from the target and a local oscillator signal of a frequency set in accordance with a transmission frequency; and a signal processing/control means 101 for generating an underwater video image from the received frequency-converted signals. COPYRIGHT: (C)2011,JPO&INPIT