Laser-acoustic detection of objects buried underwater by measuring vibration of sediment

The laser-acoustic technique proved to be effective for the detection of landmines buried in dry land. It is based on exciting vibration of ground and measuring the vibration of ground surface with a laser Doppler vibrometer. The application of this technique for the detection of landmines buried in sediment underwater is impacted by the effect of water layer on the propagation of sound and a sensing laser beam. We experimentally investigated laser-acoustic detection of objects buried in the sediment underwater. Laboratory experiments were conducted for two measurement scenarios: a sound source and a laser vibrometer positioned in air above water surface and a sound source and a laser vibrometer positioned underwater. Effects of surface waves in water, a turbulent water flow and water turbidity on detection of buried objects were investigated. [Work supported by the Office of Naval Research under Award No. N00014-21-1-2247.]