Page 11 - Acoustics Today Summer 2011

requires that the processors be capable of adapting their parameters to these changes.
Our next article is the application of signal processing in physical and engineering acoustics. Each of the constituent articles illustrates the application of signal processing tech- niques to diverse problems in nondestructive evaluation, machine and structural failure monitoring and bullet track- ing. The technologies applied are based on time-reversal, adaptive independent component analysis and array pro- cessing (wavefront curvature) techniques, respectively.
Next the application of signal processing to speech and hearing aids offers not just a brief glimpse of spectral pro- cessing techniques, but also discussions on automatic speech recognition systems and processing for hearing aids. Here technologies using simple (Fourier) spectrogram estimation to sophisticated time-frequency (Wigner-Ville) techniques are demonstrated as well as coding methodologies for recog- nition based on linear prediction and cepstral methods are illustrated along with the extension of compression tech- niques in hearing aid development.
Our final focus area is in animal bioacoustics where the
applications of signal processing abound. Our glimpse here is used to demonstrate the three-dimensional tracking and iden- tification of particular marine mammals in order to study migration patterns and behavioral habits. Classification and identification of marine animals associated with their size and orientation are discussed in processing images using gradient techniques, while the identification of whales through their clicking sounds is clearly exemplified in this contribution applying cluster analysis, spectrogram estimation, localization and change detection processing methods.
Summarizing, this issue of Acoustics Today provides a brief glimpse into the impact of acoustical signal processing technology using four diverse acoustical focus areas: under- water (ocean) acoustics, physical and engineering acoustics, speech, and animal bioacoustics. Clearly, searching the pub- lications of other focus areas represented by the ASA techni- cal committees will lead to even more diverse and sophisti- cated applications of signal processing in acoustics giving credence to the statement that “signal processing provides the thread that is interwoven throughout the fabric of the acoustics community.”
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From the Guest Editor 7