Three-dimensional acoustical imaging using micromechanical hydrophones

This paper describes aspects of the design of a 3D acoustic imaging system for use in turbid waters based upon recently-developed micromechanical hydrophones. By "three-dimensional", it is implied that the system is selective in two spatial axes (azimuth and elevation) and one temporal dimension (time/range). System concepts for both acoustic lens and beamformed systems are presented, and critical issues are identified for both system types. A laboratory test system for acoustic image acquisition is described, followed by test results and acoustic lens-based images. The images are remarkable by acoustics standards. Such a system would be of significant utility to anyone operating in otherwise zero visibility water.