Researches on the measurement of distribution image of radiated noise using focused beamforming

A method using focused beamforming to measure the distribution image (underwater image) of ship's noise sources is presented in this paper. Level linear array can measure the target image on water level, but the multi-path interference of underwater acoustic channel may affect the quality of it. Virtual time reversal mirror and virtual array can both solve the problem very well, they make the image has high resolution.