MULTIPLE MICROPHONE VOICE ACTIVITY DETECTOR
First Claim
1. A method of detecting voice activity, the method comprising:
- receiving a speech reference signal from a speech reference microphone;
receiving a noise reference signal from a noise reference microphone distinct from the speech reference microphone;
determining a speech characteristic value based at least in part on the speech reference signal;
determining a combined characteristic value based at least in part on the speech reference signal and the noise reference signal;
determining a voice activity metric based at least in part on the speech characteristic value and the combined characteristic value, wherein determining the speech characteristic value comprises determining an absolute value of the autocorrelation of the speech reference signal; and
determining a voice activity state based on the voice activity metric.
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Accused Products
Abstract
Voice activity detection using multiple microphones can be based on a relationship between an energy at each of a speech reference microphone and a noise reference microphone. The energy output from each of the speech reference microphone and the noise reference microphone can be determined. A speech to noise energy ratio can be determined and compared to a predetermined voice activity threshold. In another embodiment, the absolute value of the autocorrelation of the speech and noise reference signals are determined and a ratio based on autocorrelation values is determined. Ratios that exceed the predetermined threshold can indicate the presence of a voice signal. The speech and noise energies or autocorrelations can be determined using a weighted average or over a discrete frame size.
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Citations
25 Claims
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1. A method of detecting voice activity, the method comprising:
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receiving a speech reference signal from a speech reference microphone; receiving a noise reference signal from a noise reference microphone distinct from the speech reference microphone; determining a speech characteristic value based at least in part on the speech reference signal; determining a combined characteristic value based at least in part on the speech reference signal and the noise reference signal; determining a voice activity metric based at least in part on the speech characteristic value and the combined characteristic value, wherein determining the speech characteristic value comprises determining an absolute value of the autocorrelation of the speech reference signal; and determining a voice activity state based on the voice activity metric. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus configured to detect voice activity, the apparatus comprising:
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a speech reference microphone configured to output a speech reference signal; a noise reference microphone configured to output a noise reference signal; a speech characteristic value generator coupled to the speech reference microphone and configured to determine a speech characteristic value, wherein determining the speech characteristic value comprises determining an absolute value of the autocorrelation of the speech reference signal; a combined characteristic value generator coupled to the speech reference microphone and the noise reference microphone and configured to determine a combined characteristic value; a voice activity metric module configured to determine a voice activity metric based at least in part on the speech characteristic value and the combined characteristic value; and a comparator configured to compare the voice activity metric against a threshold and output a voice activity state. - View Dependent Claims (17, 18, 19, 20)
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21. An apparatus configured to detect voice activity, the apparatus comprising:
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means for receiving a speech reference signal; means for receiving a noise reference signal; means for determining an autocorrelation based on the speech reference signal; means for determining a cross correlation based on the speech reference signal and the noise reference signal; means for determining a voice activity metric based in part on a ratio of the absolute value of the autocorrelation of the speech reference signal to the cross correlation; and means for determining a voice activity state by comparing the voice activity metric to at least one threshold. - View Dependent Claims (22)
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23. A computer-readable media including instructions that may be utilized by one or more processors, the computer-readable media comprising:
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instructions for determining a speech characteristic value based at least in part on a speech reference signal from at least one speech reference microphone, wherein determining the speech characteristic value comprises determining an absolute value of the autocorrelation of the speech reference signal; instructions for determining a combined characteristic value based at least in part on the speech reference signal and a noise reference signal from at least one noise reference microphone; instructions for determining a voice activity metric based at least in part on the speech characteristic value and the combined characteristic value; and instructions for determining a voice activity state based on the voice activity metric.
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24. A circuit configured to detect voice activity, the circuit comprising:
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a first section adapted to receive an output speech reference signal from a speech reference microphone; a second section adapted to receive an output reference signal from a noise reference microphone; a third section comprising a speech characteristic value generator coupled to the first section configured to determine a speech characteristic value, wherein determining the speech characteristic value comprises determining an absolute value of the autocorrelation of the speech reference signal; a fourth section comprising a combined characteristic value generator coupled to the first section and the second section configured to determine a combined characteristic value; a fifth section comprising a voice activity metric module configured to determine a voice activity metric based at least in part on the speech characteristic value and the combined characteristic value; and a comparator configured to compare the voice activity metric against a threshold and output a voice activity state. - View Dependent Claims (25)
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Specification