Method of and means for adaptively filtering near-stationary noise from speech
First Claim
1. A method for adaptively filtering near stationary, long-duration noise from speech comprising the steps of:
- (a) periodically identifying the parameters representing the characteristics of an input signal comprising said noise and speech;
(b) detecting the occurrence of pauses containing said noise between speech intervals;
(c) adjusting the parameters of a filter to those identified in response to detection of a pause containing said noise; and
(d) passing the input signal through the filter followng the detected noise containing pause only until cessation of said noise is detected.
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Abstract
By identifying and analyzing the properties of the parameters of an input signal that contains speech in the presence of simultaneously occuring near-stationary noise, pauses between speech intervals as well as the termination of such noise can be recognized. When a pause interval containing noise is recognized, the parameters identified during such interval are used to set the parameters of an adaptive filter through which the input signal is passed during subsequent intervals of speech and until the noise terminates. During the time the input signal passes through the filter, the near-stationary noise is filtered out. In response to recognition of the termination of noise, the input signal is caused to by-pass the filter which is then prepared to accept the parameters of noise occuring in a subsequent pause.
132 Citations
28 Claims
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1. A method for adaptively filtering near stationary, long-duration noise from speech comprising the steps of:
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(a) periodically identifying the parameters representing the characteristics of an input signal comprising said noise and speech; (b) detecting the occurrence of pauses containing said noise between speech intervals; (c) adjusting the parameters of a filter to those identified in response to detection of a pause containing said noise; and (d) passing the input signal through the filter followng the detected noise containing pause only until cessation of said noise is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An adaptive filter for filtering near stationary, long-duration noise from speech comprising:
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(a) discriminator means for periodically identifying the parameter representing the characteristics of an input signal comprising said noise and speech, and for detecting pauses containing said noise between speech intervals; (b) filter means having adjustable parameters; (c) control means responsive to detection of the pause containing noise for adjusting the parameters of the filter means to the identified parameters and for passing the input signal through the filter means following the detected noise-containing pause only until cessation of said noise. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification