Analysis of underwater acoustic data via 3-D segmentation

The analysis of seabed structure is important in a wide variety of scientific and industrial applications. In this paper, underwater acoustic data produced by bottom-penetrating sonar (Topas) are analyzed using unsupervised volumetric segmentation, based on a three dimensional Gibbs-Markov model. The result is a concise and accurate description of the seabed, in which key structures are emphasized. This description is also very well suited to further operations, such as the enhancement and automatic recognition of important structures. Experimental results demonstrating the effectiveness of this approach are shown, using Topas data gathered in the North Sea off Horten, Norway.

An autonomous system for ocean acoustic tomography

Vertical line arrays (VLA) are a widely used apparatus in underwater acoustics with applications in sonar prediction, underwater communications and acoustic tomography, among others. Recent developments in digital electronics and communications allow for off-the-shelf development of VLA systems, with a large number of embedded acoustic and non-acoustic sensors able to fulfill application requirements, as opposed to single or few receiver configurations available until only a few years ago. Very often, the flexibility in water column sampling is achieved by splitting the VLA into modules that can be assembled according to the application. Such systems can be deployed and recovered from small vessels with a shorthanded crew, and make it possible for research labs with reduced budgets and operational means (ships and manpower) to gain control over the whole development process, from data acquisition to post-processing.