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TitleAdaptive phase calibration of a microphone array for acoustic holography
Publication TypeJournal Article
Year of Publication2010
AuthorsTeal, P.D., and Poletti M.A.
JournalJournal of the Acoustical Society of America
Pagination2368 - 2376
Date Published2010
ISSN00014966 (ISSN)
KeywordsAcoustic fields, Acoustic holography, Acoustic imaging, acoustics, Adaptive approach, Adaptive calibration, Adaptive phase, algorithm, Algorithms, article, Calibration, Equipment Design, Feasibility Studies, feasibility study, Fourier analysis, Frequency response, High frequency, High order, High quality, Holography, instrumentation, Low frequency, Microphone arrays, Microphones, Mode response, Multi-path effect, Phase mismatch, pressure, rotation, Self calibration, Signal processing, Signal Processing, Computer-Assisted, sound, sound detection, Sound fields, Sound Spectrography, Source location, standard, transducer, Transducers, vibration, Wide-band
AbstractPrevious work has indicated that a limitation on the performance of a circular microphone array for holographic sound field recording at low frequencies is phase mismatch between the microphones in the array. At low frequencies these variations become more significant than at mid-range and high frequencies because the high order phase mode responses at low frequencies are lower in amplitude. This paper demonstrates the feasibility of a "self-calibration" method. The basis of the calibration is to estimate the location of one or more wide-band sources using mid-range frequencies and to use this source location information to perform correction to the array at low frequencies. In its simplest form the calibration must be performed in an anechoic environment, since multipath effects at widely differing frequencies are uncorrelated. The approach is first demonstrated in such an environment using recordings from an array of high quality microphones. The technique is then extended to an adaptive calibration that can be used in an environment that is somewhat reverberant. The validity of the adaptive approach is demonstrated using recordings from an array of inexpensive microphones. © 2010 Acoustical Society of America.

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