System for separating speech from background noise
First Claim
1. An apparatus for separating speech from background noise, comprising:
- means for inputting speech contaminated with background noise to provide a noisy speech signal;
means for inputting primarily the background noise contaminating the speech to provide a reference signal;
signal processing means for implementing an adaptive least-squares adaptation method to obtain an estimate of the power spectrum of the noise contaminating the speech from a plurality of recent samples of the power spectrum of the reference signal, and for subtracting said estimate of the power spectrum of the noise contaminating speech from the total power spectrum of said noisy speech signal to obtain an estimate of the power spectrum of the speech.
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Abstract
A digital signal processing system provides to sequences of power spectra in each of two signal channels, one channel, termed the "speech" channel, containing speech and environmental noise and the other channel, termed the "reference" channel, containing primarily the same environmental noise. An adaptive filtering technique is employed using the power spectra in both channels when speech is not present in the speech channel to obtain a relationship between the environmental noise power spectra in the two channels. When speech is present in the speech channel, a prediction of the environmental noise power spectrum on that channel is obtained from the power spectrum of the noise on the reference channel and the relationship between the noise power spectra on the two channels previously obtained. Thus the noise power spectrum be extracted from the power spectrum of the speech and noise in the speech channel. The result is that the speech will be more easily recognizable by either human listeners or speech recognition systems.
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Citations
13 Claims
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1. An apparatus for separating speech from background noise, comprising:
- means for inputting speech contaminated with background noise to provide a noisy speech signal;
means for inputting primarily the background noise contaminating the speech to provide a reference signal;
signal processing means for implementing an adaptive least-squares adaptation method to obtain an estimate of the power spectrum of the noise contaminating the speech from a plurality of recent samples of the power spectrum of the reference signal, and for subtracting said estimate of the power spectrum of the noise contaminating speech from the total power spectrum of said noisy speech signal to obtain an estimate of the power spectrum of the speech. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- means for inputting speech contaminated with background noise to provide a noisy speech signal;
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8. A method of separating background noise from a noisy speech signal, comprising:
- continually monitoring background noise to provide a reference signal;
processing the reference signal to obtain an estimate of the power spectrum thereof using an adaptive least-squares adaptation method from a plurality of recent samples of the power spectrum of the reference signal; and
processing the noisy speech signal by subtracting the estimate from the total power spectrum of the noisy signal to obtain an estimate of the power spectrum of the speech. - View Dependent Claims (9, 10, 11, 12, 13)
- continually monitoring background noise to provide a reference signal;
Specification