Dolphin echolocation research: VRML virtual replay capabilities
SPAWAR Systems Center San Diego
Wednesday, October 30, 2002
3:00 p.m. – Pacific Forum
SPAWAR Systems Center San Diego develops marine mammal
systems used by the U.S. Navy in mine hunting applications. Dolphins are
trained to locate and mark bottom mines to support the U.S. Navy Mine
Counter Measures Mission. Dolphins are currently able to conduct much more
effective mine hunting than existing manmade sonar systems. I will
describe a research project sponsored by the Office of Naval Research.
This project, which uses free-swimming dolphins to perform mine hunting
tasks, provides levels of instrumentation never before available.
The dolphin is trained to carry a bite-plate-mounted
instrumentation package while searching for inert mine-like shapes on the
seafloor. The instrumentation package records the dolphin’s underwater
navigational data (heading, pitch, roll, depth, speed), as well as a
wealth of dolphin echolocation data (e.g., outgoing echolocation clicks,
high gain binaural receiver data streams modeled after the dolphin’s
hearing capabilities). A sixty-second search by the dolphin results in a
data set of over 100 MB.
Virtual Reality Modeling Language (VRML) is used as a
research tool to virtually replay the dolphin’s underwater search for
two purposes. The first purpose is to provide researchers much more
insight into what the dolphin does when it conducts its echolocation
search (i.e., better situational understanding of the dolphin’s search
strategies). The second purpose is to allow researchers to target selected
sections of the large data set for more detailed signal processing
analysis, such as testing signal processing algorithms to automatically
detect the mine-like object’s echoes within the binaural echo stream.
Samples of the VRML replay capabilities will be demonstrated in the
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