Page 39 - Acoustics Today Summer 2011

SIGNAL AND IMAGE PROCESSING TECHNIQUES AS APPLIED TO ANIMAL BIOACOUSTICS PROBLEMS
Chris O. Tiemann
Applied Research Laboratories, University of Texas Austin, Texas 76758
Jules S. Jaffe, Paul. L. D. Roberts
Marine Physical Laboratory, Scripps Inst. of Oceanography University of California San Diego, La Jolla California 92106
Natalia A. Sidorovskaia
Department of Physics, University of Louisiana at Lafayette Lafayette, Louisiana 70504
George E. Ioup, Juliette W. Ioup
Department of Physics, University of New Orleans New Orleans, Louisiana 70148
Alexander Ekimov
National Center for Physical Acoustics, University of Mississippi Oxford, Mississippi 38677
Sean K. Lehman
Lawrence Livermore National Laboratory Livermore, California 94551
Adopting the philosophy that diverse problems have similar solutions, signal and image pro- cessing techniques have been success- fully used to solve problems in animal bioacoustics. Three examples are offered where standard time-series analysis techniques have been applied to data with biological origins:
– “Three-dimensional passive acoustic
localization technique for marine
mammals” uses spectrograms of
acoustic time series followed by a model-based processor;
– “Applying diffraction theory to measure acoustically the in-situ orientation of marine animals” uses autocorrela-
“This work explores the implementation of an algorithm to compute animal orientation from wide-band backscatter data collected in the lab from live fish.”
tions followed by Radon transforms; – “Identifying individual clicking whales acoustically” uses spectrograms.
Three-dimensional passive acoustic localization techniques for marine mammals
Passive underwater acoustic meth- ods for monitoring the activity of marine mammals have been used for many years in censuring or behavioral studies because they are unobtrusive
and can function when animals are out of sight. Methods for tracking the movement of animals underwater through analysis of their recorded vocalizations have now advanced
Fig. 1. Time aligned spectral sum excerpts, each starting with a direct-path arrival at relative time 0 sec, presented as a 2D surface. Persistent arrivals with identified acoustic path geometries are labeled. With permission of Canadian Acoustics.
Animal Bioacoustics 35