Method and apparatus for passive acoustic source localization for video camera steering applications
First Claim
1. A method of locating an acoustic source within a physical environment with use of a plurality of microphones placed at different locations within said physical environment, each microphone receiving an acoustic signal resulting from said acoustic source and generating a corresponding microphone output signal in response thereto, the method comprising the steps of:
- estimating a first impulse response representative of the acoustic signal received by a first one of said microphones and estimating a second impulse response representative of the acoustic signal received by a second one of said microphones;
determining a relative time delay of arrival between said acoustic signal received by said first one of said microphones and said acoustic signal received by said second one of said microphones, said determination based on said estimated first impulse response and on said estimated second impulse response; and
locating said acoustic source within said physical environment based on said determined relative time delay of arrival, wherein the step of estimating the first and second impulse responses includes filtering said microphone output signal of said first one of said microphones with a first adaptive filter and filtering said microphone output signal of said second one of said microphones with a second adaptive filter; and
, said step of estimating the first and second impulse responses further includes adjusting said first adaptive filter to provide an estimate of said second impulse response and adjusting said second adaptive filter to provide an estimate of said first impulse response.
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Abstract
A real-time passive acoustic source localization system for video camera steering advantageously determines the relative delay between the direct paths of two estimated channel impulse responses. The illustrative system employs an approach referred to herein as the “adaptive eigenvalue decomposition algorithm” (AEDA) to make such a determination, and then advantageously employs a “one-step least-squares algorithm” (OSLS) for purposes of acoustic source localization, providing the desired features of robustness, portability, and accuracy in a reverberant environment. The AEDA technique directly estimates the (direct path) impulse response from the sound source to each of a pair of microphones, and then uses these estimated impulse responses to determine the time delay of arrival (TDOA) between the two microphones by measuring the distance between the first peaks thereof (i.e., the first significant taps of the corresponding transfer functions). In one embodiment, the system minimizes an error function (i.e., a difference) which is computed with the use of two adaptive filters, each such filter being applied to a corresponding one of the two signals received from the given pair of microphones. The filtered signals are then subtracted from one another to produce the error signal, which is minimized by a conventional adaptive filtering algorithm such as, for example, an LMS (Least Mean Squared) technique. Then, the TDOA is estimated by measuring the “distance” (i.e., the time) between the first significant taps of the two resultant adaptive filter transfer functions.
157 Citations
27 Claims
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1. A method of locating an acoustic source within a physical environment with use of a plurality of microphones placed at different locations within said physical environment, each microphone receiving an acoustic signal resulting from said acoustic source and generating a corresponding microphone output signal in response thereto, the method comprising the steps of:
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estimating a first impulse response representative of the acoustic signal received by a first one of said microphones and estimating a second impulse response representative of the acoustic signal received by a second one of said microphones;
determining a relative time delay of arrival between said acoustic signal received by said first one of said microphones and said acoustic signal received by said second one of said microphones, said determination based on said estimated first impulse response and on said estimated second impulse response; and
locating said acoustic source within said physical environment based on said determined relative time delay of arrival, wherein the step of estimating the first and second impulse responses includes filtering said microphone output signal of said first one of said microphones with a first adaptive filter and filtering said microphone output signal of said second one of said microphones with a second adaptive filter; and
,said step of estimating the first and second impulse responses further includes adjusting said first adaptive filter to provide an estimate of said second impulse response and adjusting said second adaptive filter to provide an estimate of said first impulse response. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for locating an acoustic source within a physical environment comprising:
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a plurality of microphones placed at different locations within said physical environment, each microphone receiving an acoustic signal resulting from said acoustic source and generating a corresponding microphone output signal in response thereto;
a first adaptive filter applied to said microphone output signal of a first one of said microphones, and a second adaptive filter applied to said microphone output signal of a second one of said microphones, the second adaptive filter estimating a first impulse response representative of the acoustic signal received by said first one of said microphones, and the first adaptive filter estimating a second impulse response representative of the acoustic signal received by said second one of said microphones;
means for determining a relative time delay of arrival between said acoustic signal received by said first one of said microphones and said acoustic signal received by said second one of said microphones, said determination based on said estimated first impulse response and on said estimated second impulse response; and
means for locating said acoustic source within said physical environment based on said determined relative time delay of arrival. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification
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- Resources
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Current AssigneeAvago Technologies International Sales Pte Limited (Broadcom, Inc.)
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Original AssigneeAgere Systems Incorporated (Broadcom, Inc.)
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InventorsHuang, Yiteng, Elko, Gary Wayne, Benesty, Jacob
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Primary Examiner(s)Nguyen, Duc
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Assistant Examiner(s)LAO, LUNSEE
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Application NumberUS09/498,561Time in Patent Office1,761 DaysField of Search381/92, 381/91, 381/71.12, 381/71.11, 381/94.7, 381/94.8, 381/94, 381/122, 381/56, 348/14.08, 348/14.01, 348/14.15, 348/17, 348/18, 348/19US Class Current381/92CPC Class CodesG01S 5/22 Position of source determin...H04N 7/142 Constructional details of t...H04R 1/406 microphonesH04R 2201/401 2D or 3D arrays of transducersH04R 3/005 for combining the signals o...
