Adaptive speech filter
First Claim
1. A method for estimating the frequency components of an information signal from an input signal containing both the information signal and noise, said method comprising:
- a means to produce a set of input frequency components, one for each frequency band and for each frequency component;
calculating the total power in each input frequency component;
estimating the power of the information signal included therein;
calculating a modified gain for each frequency band as a function of the total power, the estimate of the power of the information signal and a previous estimate of a noise power;
multiplying the input frequency component by said modified gain to thereby produce an estimate of the power of the frequency component of said information signal; and
estimating a new noise power estimate from the previous estimate of the noise power and the difference between the total power in the input frequency component and the estimate of the power of the frequency component of said information signal, wherein estimating the new noise power estimate occurs regardless of whether there is a pause in the infornation signal.
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Abstract
This invention relates to an improved adaptive spectral estimator for estimating the spectral components in a signal containing both an information signal, such as speech and noise. The improvements relate to a noise power estimator and a computationally efficient gain calculation method. The adaptive spectral estimator is particularly suited to implementation using digital signal processing and can be used to provide improved spectral estimates of the information signal. It can be combined with a speech or voice recognition system. A further object of the invention is to provide an accurate method for voice detection.
96 Citations
16 Claims
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1. A method for estimating the frequency components of an information signal from an input signal containing both the information signal and noise, said method comprising:
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a means to produce a set of input frequency components, one for each frequency band and for each frequency component; calculating the total power in each input frequency component; estimating the power of the information signal included therein; calculating a modified gain for each frequency band as a function of the total power, the estimate of the power of the information signal and a previous estimate of a noise power; multiplying the input frequency component by said modified gain to thereby produce an estimate of the power of the frequency component of said information signal; and estimating a new noise power estimate from the previous estimate of the noise power and the difference between the total power in the input frequency component and the estimate of the power of the frequency component of said information signal, wherein estimating the new noise power estimate occurs regardless of whether there is a pause in the infornation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for estimating the noise power ofl frequency components of an information signal from an input signal containing both the information signal and noise, said system comprlsing:
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means to produce a set of input frequency components, one for each frequency band and for each frequency component; a first calculating means for calculating the total power in each input frequency component; an estimating means for estimating the power of the information signal included therein; a second calculating means for calculating a modified gain for each frequency band as a function of the total power, the estimate of the power of the information signal and a previous estimate of a noise power; and gain multiplying means for multiplying the input frequency component by said modified gain to thereby produce an estimate of the power of the frequency component of said information signal whereby said estimating means estimates a new noise power estimate from the previous estimate of the noise power and the difference between the total power in the input frequency component and the estimate of the power of the frequency component of said information signal, wherein estimating the new noise power estimate occurs regardless of whether there is a pause in the information signal. - View Dependent Claims (14, 15, 16)
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Specification