Reducing noise in audio systems
First Claim
1. A method for processing audio signals generated by two or more microphones receiving acoustic signals, comprising the steps of:
- (a) generating a ratio of sum and difference signal powers for the audio signals; and
(b) filtering at least one of the audio signals based on the ratio to reduce a portion of the audio signals resulting from one or more of (i) incoherence between the audio signals and (ii) one or more audio-signal sources having propagation speeds different from the acoustic signals.
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Abstract
Two or more microphones receive acoustic signals and generate audio signals that are processed to determine what portion of the audio signals result from (i) incoherence between the audio signals and/or (ii) audio-signal sources having propagation speeds different from the acoustic signals. The audio signals are filtered to reduce that portion of one or more of the audio signals. The present invention can be used to reduce turbulent wind-noise resulting from wind or other airjets blowing across the microphones. Time-dependent phase and amplitude differences between the microphones can be compensated for based on measurements made in parallel with routine audio system processing.
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Citations
55 Claims
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1. A method for processing audio signals generated by two or more microphones receiving acoustic signals, comprising the steps of:
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(a) generating a ratio of sum and difference signal powers for the audio signals; and (b) filtering at least one of the audio signals based on the ratio to reduce a portion of the audio signals resulting from one or more of (i) incoherence between the audio signals and (ii) one or more audio-signal sources having propagation speeds different from the acoustic signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 44, 45, 46, 50, 53)
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8. An audio system for processing audio signals generated by two or more microphones receiving acoustic signals, the audio system comprising:
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(a) a signal processor configured to generate a ratio of sum and difference signal powers for the audio signals; and (b) a filter configured to filter at least one of the audio signals based on the ratio to reduce a portion of the audio signals resulting from one or more of (i) incoherence between the audio signals and (ii) one or more audio-signal sources having propagation speeds different from the acoustic signals. - View Dependent Claims (9, 10, 11, 12, 13, 14, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 47, 48, 49, 51, 54)
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15. A consumer device comprising:
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(a) two or more microphones configured to receive acoustic signals and to generate audio signals; (b) a signal processor configured to generate a ratio of sum and difference signal powers for the audio signals; and (c) a filter configured to filter at least one of the audio signals based on the ratio to reduce a portion of the audio signals resulting from one or more of (i) incoherence between the audio signals and (ii) one or more audio-signal sources having propagation speeds different from the acoustic signals. - View Dependent Claims (16, 42, 43, 52, 55)
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Specification