Microphone occlusion detector
First Claim
1. An electronic system for audio noise processing and for noise reduction, using a plurality of microphones, comprising:
- a first noise estimator to process a first audio signal from a first one of the microphones, and generate a first noise estimate;
a second noise estimator to process the first audio signal, and a second audio signal from a second one of the microphones, in parallel with the first noise estimator, and generate a second noise estimate;
a combiner-selector to receive the first and second noise estimates, and to generate an output noise estimate using the first and second noise estimates; and
a microphone occlusion detector to process the first and second audio signals including to band pass filter the first and second audio signals and to generate a microphone occlusion signal using the processed first and second audio signals, wherein the microphone occlusion signal represents a measure of how severely or how likely it is that one of the microphones is occluded, andwherein the combiner-selector is to generate its output noise estimate also based on the occlusion signal.
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Abstract
Digital signal processing microphone occlusion detection is described that can be used with a noise suppression system that uses two types of noise estimators, including a more aggressive one based on two audio signals (such as for non-stationary noises) and a less aggressive one based on one audio signal (such as for stationary noises). Decisions are made on how to select or combine the outputs of the noise estimators into a usable noise estimate, based on an occlusion function. The occlusion detection may alternatively be used to trigger an alert to users of multi-microphone audio processing systems, such as smart phones, headsets, laptops and tablet computers. Other embodiments are also described and claimed.
33 Citations
25 Claims
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1. An electronic system for audio noise processing and for noise reduction, using a plurality of microphones, comprising:
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a first noise estimator to process a first audio signal from a first one of the microphones, and generate a first noise estimate; a second noise estimator to process the first audio signal, and a second audio signal from a second one of the microphones, in parallel with the first noise estimator, and generate a second noise estimate; a combiner-selector to receive the first and second noise estimates, and to generate an output noise estimate using the first and second noise estimates; and a microphone occlusion detector to process the first and second audio signals including to band pass filter the first and second audio signals and to generate a microphone occlusion signal using the processed first and second audio signals, wherein the microphone occlusion signal represents a measure of how severely or how likely it is that one of the microphones is occluded, and wherein the combiner-selector is to generate its output noise estimate also based on the occlusion signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A microphone occlusion detector comprising:
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means for processing first and second audio signals that are from first and second microphones, respectively, including means for band pass filtering the signals; and means for evaluating a microphone occlusion function that represents a measure of how severely or how likely it is that the second microphone is occluded, using the processed first and second audio signals. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A microphone occlusion detector that uses multiple occlusion component signals, comprising:
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means for processing first and second audio signals that are from first and second microphones, respectively, including means for band pass filtering the signals; means for evaluating a first occlusion component function that represents a measure of how severely or how likely it is that the second microphone is occluded during speech activity, using the band pass filtered first and second audio signals; means for evaluating a second occlusion component function that represents a measure of how severely or how likely it is that the second microphone is occluded during no speech activity, using the band pass filtered first and second audio signals; and means for selecting between the first and second occlusion component functions, wherein in a no speech condition, the second component function is selected but not the first component function, and in a no speech condition where the level of background noise is at a high level, the first component function is selected but not the second compound function. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method for detecting occlusion of a microphone, comprising:
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processing band pass filtered versions of first and second audio signals that are from first and second microphones, respectively, to compute a power ratio (PR) or a magnitude ratio (MR) of the band pass filtered first and second signals; and evaluating an occlusion function, being a measure of how occluded the second microphone is, as a function of PR or MR, wherein the occlusion function is one of a) a curve that abruptly indicates substantial occlusion when the PR or MR is greater than a threshold, and abruptly indicates no substantial occlusion when the PR or MR is smaller than the threshold, b) a curve that gradually indicates increasing occlusion when the PR or MR is greater than a threshold, and abruptly indicates no substantial occlusion when the PR or MR is smaller than the threshold, and c) a logistic function. - View Dependent Claims (23, 24, 25)
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Specification