Abstract: Acoustic arrays transmitting and/or receiving multiple, angularly dispersed acoustic beams are used to generate 2D and 3D images. The acoustic arrays may comprise frequency-steered acoustic arrays provided in one-dimensional linear and two dimensional planar and curvilinear configurations, which may be operated as single order or multiple order arrays, may employ periodic or non-periodic transducer element spacing, and may be mechanically scanned to generate 2D and 3D volumetric data. Methods and systems for operating acoustic arrays in a frequency-steered mode in combination a mechanical beam steering mode, electronic time-delay and phase shift beam forming modes, and phase comparison angle estimation modes are also provided. Methods for generating two and three dimensional images of underwater target scenes using multi-beam acoustic imaging systems are disclosed.

Abstract: Frequency-steered acoustic arrays transmitting and/or receiving multiple, angularly dispersed acoustic beams are used to generate 2D and 3D images. Input pulses to the arrays are generally non-linear, frequency-modulated pulses. Frequency-steered acoustic arrays may be provided in one-dimensional linear and two dimensional planar and curvilinear configurations, may be operated as single order or multiple order arrays, may employ periodic or non-periodic transducer element spacing, and may be mechanically scanned to generate 2D and 3D volumetric data. Multiple imaging fields of view may generated in different directions by switching the polarity of phase-shifted array transducer elements. Multiple frequency-steered arrays arranged in an X-configuration provide a wide, contiguous field of view and multiple frequency steered arrays arranged in a T-configuration provide orthogonally oriented fields of view.

Abstract: An acoustic video camera system uses acoustic data acquisition systems to produce digital video imagery capable of interfacing with host equipment that operates using standard video formats compatible with video images obtained using optical systems. The acoustic video camera comprises an Acoustic Imager, a Digital Image Compression Component, an I/O and Processing component, and, optionally, an Image Analytics Component. System analytics may provide automated target identification and tracking. All of these components may be incorporated in a submersible acoustic imaging unit having communications capability for interfacing with a host display and control system.

Abstract: A sonar array for forming multiple transmit and/or receive acoustic beams by a frequency beamforming technique. In frequency division beamforming, beam steering direction is made a function of frequency by driving (receiving) each element of a uniformly spaced line array by a signal which leads or lags its nearest neighbor by a fixed phase shift, ??. This permits scanning a transmit and/or receive beam through a range of angles by changing its frequency. The same principle can be used to form multiple simultaneous transmit and/or receive beams. This is accomplished by transmitting a wide bandwidth signal and receiving the echoes through a spectrum analyzer. Each frequency bin of the spectrum analyzer then corresponds to a beam pointing in its own unique direction. Advantages of such a sonar system include improved cost, weight, and size versus performance for a variety of systems including ahead looking sonars and bottom mapping sonars.