Page 10 - Acoustics Today Summer 2011

FROM THE EDITOR
Dick Stern
1150 Linden Hall Road Boalsburg, Pennsylvania 16827
I am extremely grateful to James Candy for his outstanding work as guest editor for this comprehen- sive issue on signal processing in acoustics. I also wish to thank the authors for their excellent articles. Each discussed their area of expertise using applicable examples. We all hope that those not familiar with signal processing technology will see its usefulness in their own research and give it a try.
See you in San Diego. Dick Stern
FROM THE GUEST EDITOR
James. V. Candy
Lawrence Livermore National Laboratory and University of California, Santa Barbara Livermore, California 94551
“Signal processing is the extrac-
tion of desired information while
rejecting the extraneous,” (Acoustics
Today, Vol. 4(3), 2008). In the
sequence of articles to follow, we
illustrate the broad reaches of signal
processing within the acoustics com-
munity. Signal processing in all of its
forms can range from the simple
(e.g., Fourier transforms) to the
highly sophisticated (e.g., Bayesian
processors) as well as a wealth of
techniques that lie in-between.
Perhaps the best way to illustrate the
various approaches is to choose a
cross-section of different focus areas,
nicely organized by the Acoustical
Society of America (ASA) into technical committees, and a group of researchers within to tell their stories. Even though it is clearly a limited sampling of the areas that could easily be extended into an encyclopedia (Signal Processing in Acoustics, Springer, 2008), these articles will provide a simple perspective of the impact of this discipline as well as show the current and potential applications of signal processing technology to a wide-berth of acoustics problems.
Perhaps one of the most challeng- ing and advanced areas in acoustical signal processing technology is underwater ocean acoustic signal pro- cessing and as illustrated in our first article where we are given a glimpse of the recent efforts in utilizing model- based Bayesian processing techniques in ocean acoustics. Ocean acoustic signal processing has been one of the major areas heavily influenced by processing techniques. It has motivat- ed the development and evolution of novel signal processing technologies (e.g., matched-field processing, beam- forming) and a wealth of applications (e.g., time reversal, wavelets). This
article focuses on sequential Bayesian model-based tech- niques applied to: towed array (synthetic aperture) tracking of a moving acoustic source, time delay estimation for local- ization and a geoacoustic inversion parameter estimation (tracking) all of which are quite challenging from a signal processing perspective. The sequential nature of the solu- tions are based on the fact that sound propagation in this dispersive, varying (e.g., temperature) ocean environment
6 Acoustics Today, July 2011