Under-Ice Sonar Visualization

The complexity of a data set such as ice keels lends itself perfectly to immersive visualization. The keel visualization environment displays sound energy in a volumetric form. Placing the user's viewpoint within that volume with a first-person perspective, rather than the current third-person perspective, should assist the observer.

Currently, the manipulation of the 3-D scene is dependent upon the standard keyboard and mouse. Planned upgrades to the under-ice visualization environment include a transition to an immersive display and 3-D gestural interface. The immersive display we have in mind is a head-mounted display. This design is portable and lends itself easily to use in tight quarters, such as those on a submarine.

When operating within a purely 3-D environment, the two-dimensional user interface becomes cumbersome. An elegant solution is to use a gestural interface in the form of a standard game pad with a sourceless inertial tracker attached. The object is to allow the user to position the viewpoint easily in any way. This functionality allows the user to better understand the complex visual representations of target strength and reverberation levels. Figure 9 demonstrates a prototype of the next step in the evolution of the UEV software.

Figure 9. Planned Gestrual-Based UEV Software

A flexible, modularized, 3-D data fusion visualization system to study and data-mine under-ice acoustic information has widespread applicability for both military and civilian use. Building upon work originally sponsored by the Office of Naval Research (ONR) and years of Arctic experience, the Naval Undersea Warfare Center is developing pioneering visualizations for the integrated understanding of the acoustic properties of complex ocean environments, such as those under the pack ice in the Arctic Ocean and in shallow water coastal regions throughout the world.

Because the Linux operating system is so adaptable and generic, it has been easy to transform the software originally written for Silicon Graphics machines to run now on Linux. Furthermore, because the US Navy operates in both the Linux and Microsoft Windows environments, Linux has provided a cost-effective means to update, compile and test the UEV software. We have found that if the software compiles under Linux without errors, it almost always compiles under Visual C++, as long as the laborious process of ensuring all the Microsoft Windows paths are set up properly. Linux provides a unique environment for rapid prototyping, which results in software compatible with both UNIX and Microsoft Windows operating systems, thus qualifying as a valuable fleet software expeditor.

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