Underwater far-field multi-directional compressive sensing metamaterial acoustic imaging device

Underwater imaging plays an important role in sonar detection. Compressive sensing can achieve high-precision airborne sound source localization with a small computational effort, but underwater target localization and ranging have not been fully achieved. This study proposes a metamaterial-based compressive sensing imaging method for underwater sound source localization and target imaging. To overcome the poor wave manipulation performance caused by the impedance difference between water and the structure, a strong coupling interaction between the flexible structure and the medium is introduced to reduce reflection and scattering, dramatically improving the acoustic signal transmission amplitude via the resonance mechanism. Analytical and numerical results show that this device can achieve directional irrelevant modulation of incident acoustic waves in different directions. Besides, the multi-information fusion compressive sensing method and dual-sensor joint compressive sensing method can reconstruct the sound source information from the received mixed signals. Experimental results show that the metamaterial-based compressive sensing imaging device realizes the perception and localization of a single sound source underwater in multiple directions. The metamaterial-based hydroacoustic imaging device eliminates the dependence on large-caliber arrays and complex control systems, thus opening the way to establish a sonar system with low cost and high precision.