SYSTEMS, METHODS, APPARATUS, AND COMPUTER READABLE MEDIA FOR EQUALIZATION
First Claim
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1. A method of using information from a near-end noise reference to process a reproduced audio signal, said method comprising:
- applying a subband filter array to the near-end noise reference to produce a plurality of time-domain noise subband signals;
based on information from the plurality of time-domain noise subband signals, calculating a plurality of noise subband excitation values;
based on the plurality of noise subband excitation values, calculating a plurality of subband gain factors; and
applying the plurality of subband gain factors to a plurality of frequency bands of the reproduced audio signal in a time domain to produce an enhanced audio signal,wherein said calculating a plurality of subband gain factors includes, for each of said plurality of subband gain factors, raising a value that is based on a corresponding noise subband excitation value to a power of alpha to produce a corresponding compressed value, wherein the subband gain factor is based on the corresponding compressed value and wherein alpha has a positive nonzero value that is less than one.
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Abstract
Enhancement of audio quality (e.g., speech intelligibility) in a noisy environment, based on subband gain control using information from a noise reference, is described.
88 Citations
41 Claims
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1. A method of using information from a near-end noise reference to process a reproduced audio signal, said method comprising:
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applying a subband filter array to the near-end noise reference to produce a plurality of time-domain noise subband signals; based on information from the plurality of time-domain noise subband signals, calculating a plurality of noise subband excitation values; based on the plurality of noise subband excitation values, calculating a plurality of subband gain factors; and applying the plurality of subband gain factors to a plurality of frequency bands of the reproduced audio signal in a time domain to produce an enhanced audio signal, wherein said calculating a plurality of subband gain factors includes, for each of said plurality of subband gain factors, raising a value that is based on a corresponding noise subband excitation value to a power of alpha to produce a corresponding compressed value, wherein the subband gain factor is based on the corresponding compressed value and wherein alpha has a positive nonzero value that is less than one. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 41)
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19. An apparatus for using information from a near-end noise reference to process a reproduced audio signal, said apparatus comprising:
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means for filtering the near-end noise reference to produce a plurality of time-domain noise subband signals; means for calculating, based on information from the plurality of time-domain noise subband signals, a plurality of noise subband excitation values; means for calculating, based on the plurality of noise subband excitation values, a plurality of subband gain factors; and means for applying the plurality of subband gain factors to a plurality of frequency bands of the reproduced audio signal in a time domain to produce an enhanced audio signal, wherein said calculating a plurality of subband gain factors includes, for each of said plurality of subband gain factors, raising a value that is based on a corresponding noise subband excitation value to a power of alpha to produce a corresponding compressed value, wherein the subband gain factor is based on the corresponding compressed value and wherein alpha has a positive nonzero value that is less than one. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An apparatus for using information from a near-end noise reference to process a reproduced audio signal, said apparatus comprising:
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a subband filter array configured to filter the near-end noise reference to produce a plurality of time-domain noise subband signals; a first calculator configured to calculate, based on information from the plurality of time-domain noise subband signals, a plurality of noise subband excitation values; a second calculator configured to calculate, based on the plurality of noise subband excitation values, a plurality of subband gain factors; and a filter bank configured to apply the plurality of subband gain factors to a plurality of frequency bands of the reproduced audio signal in a time domain to produce an enhanced audio signal, wherein said second calculator is configured, for each of said plurality of subband gain factors, to raise a value that is based on a corresponding noise subband excitation value to a power of alpha to produce a corresponding compressed value, wherein the subband gain factor is based on the corresponding compressed value and wherein alpha has a positive nonzero value that is less than one. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification