Cross air–water interface hydroacoustic signal detection based on laser speckle imaging

A cross air-water interface hydroacoustic signal detection method based on microvibration detection at the air-water interface is proposed.Laser speckles modulated by water surface acoustic waves are recorded and used as an information carrier.Phase correlation and multichannel fusion algorithms are used to extract and enhance hydroacoustic signals.Wide frequency range (200 Hz to 20 kHz) underwater acoustic signals are detected with a frequency relative error smaller than 0.5%.Several common artificial and natural hydroacoustic signals are used as source signals and correctly reconstructed.The average intelligibility of recovered humpback whale signals evaluated with the normalized subband envelope correlation algorithm is 0.52 0.02.