Method and Noise Suppression Circuit Incorporating a Plurality of Noise Suppression Techniques

• US 20080159560A1
• Filed: 08/21/2007
• Published: 07/03/2008
• Est. Priority Date: 12/30/2006
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: CLARK, JOEL A., SONG, JIANMING J.
• Granted Patent: US 9,966,085 B2
• Time in Patent Office: Days
• US Class Current: 381/94.1
• CPC Class Codes: G10L 15/142 Hidden Markov Models [HMMs]
• CPC Class Codes: G10L 15/20 Speech recognition techniques specially adapted for robustness in adverse environments, e.g. in noise, of stress induced speech G10L21/02 takes precedence
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 21/00 Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility G10L19/00 takes precedence
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: G10L 21/0232 Processing in the frequency domain
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10

Abstract

A noise suppression circuit for use in an audio signal processing circuit is provided. The noise suppression circuit includes a plurality of different types of noise activity detectors, which are each adapted for detecting the presence of a different type of noise in a received signal. The noise suppression circuit further includes a plurality of different types of noise reduction circuits, which are each adapted for removing a different type of detected noise, where each noise reduction circuit respectively corresponds to one of the plurality of noise activity detectors. The respective noise reduction circuit is then selectively activated to condition the received signal to reduce the amount of the detected types of noise, when each one of the plurality of noise activity detectors detects the presence of a corresponding type of noise in the received signal.

Claims

1. A noise suppression circuit for use in an audio signal processing circuit, the noise suppression circuit comprising:

a plurality of different types of noise activity detectors each adapted for detecting the presence of a different type of noise in a received signal; and

a plurality of different types of noise reduction circuits each adapted for removing a different type of detected noise, where each noise reduction circuit respectively corresponds to one of the plurality of noise activity detectors;

wherein when each one of the plurality of noise activity detectors detects the presence of a corresponding type of noise in the received signal, the respective noise reduction circuit is selectively activated to condition the received signal to reduce the amount of the detected types of noise.

2. A noise suppression circuit in accordance with claim 1, wherein the plurality of different types of noise activity detectors include a babble noise activity detector and a stationary noise activity detector.

3. A noise suppression circuit in accordance with claim 2, wherein the stationary noise activity detector includes a spectrum domain noise activity detector and a time domain noise activity detector.

4. A noise suppression circuit in accordance with claim 2, wherein the babble noise activity detector includes a gaussian mixture model.

5. A noise suppression circuit in accordance with claim 4, wherein the gaussian mixture model includes a speech model for detecting the presence of a desired voice signal, and a noise model for detecting the presence of babble noise.

6. A noise suppression circuit in accordance with claim 5, wherein the detected voice signal and the detected babble noise are used to formulate a signal to be used for a corresponding one of the noise reduction circuits.

7. A noise suppression circuit in accordance with claim 5, wherein the detected babble noise is used to update the noise model.

8. A noise suppression circuit in accordance with claim 1, wherein the plurality of different types of noise reduction circuits includes a noise attenuation circuit and a noise subtraction circuit.

9. A noise suppression circuit in accordance with claim 4, wherein the plurality of different types of noise activity detectors includes a babble noise activity detector and a stationary noise activity detector, and wherein the noise attenuation circuit corresponds to the stationary noise detector, and the noise subtraction circuit corresponds to the babble noise detector.

10. A noise suppression circuit in accordance with claim 1 further comprising a comfort noise source for producing a comfort noise signal, and a mixer for combining the comfort noise signal with the received signal, which has been conditioned to reduce the amount of the detected types of noise.

11. A noise suppression circuit in accordance with claim 1, wherein the noise suppression circuit is incorporated in a two way communication device including a microphone and a speaker.

12. A noise suppression circuit in accordance with claim 11 further comprising an echo cancellation circuit for receiving a signal to be reproduced by the speaker and removing any speaker reproduced signal detected by the microphone.

13. A noise suppression circuit in accordance with claim 1, wherein the noise suppression circuit is incorporated as part of a radio frequency telephone.

14. A two way communication device comprising:

a transceiver for communicating with a remote radio source;

a speaker for reproducing an audio signal received from a remote radio source;

a microphone for detecting an audio signal to be transmitted to the remote radio source; and

an audio signal processing circuit including a noise suppression circuit for conditioning the audio signal detected by the microphone prior to being transmitted to the remote radio source by the transceiver, the noise suppression circuit comprising

a plurality of different types of noise activity detectors each adapted for detecting the presence of a different type of noise in an audio signal detected by the microphone, and

a plurality of different types of noise reduction circuits each adapted for removing a different type of detected noise, where each noise reduction circuit respectively corresponds to one of the plurality of noise activity detectors,

wherein when each one of the plurality of noise activity detectors detects the presence of a corresponding type of noise in the audio signal detected by the microphone, the respective noise reduction circuit is selectively activated to condition the audio signal detected by the microphone to reduce the amount of the detected types of noise.

15. A two way communication device in accordance with claim 14 wherein the noise suppression circuit further comprises a comfort noise source for producing a comfort noise signal, and a mixer for combining the comfort noise signal with the audio signal detected by the microphone, which has been conditioned to reduce the amount of the detected types of noise.

16. A two way communication device in accordance with claim 14 the noise suppression circuit further comprises an echo cancellation circuit for receiving the audio signal received from the remote radio source to be reproduced by the speaker and removing any speaker reproduced signal detected by the microphone.

17. A method for suppressing noise in an audio signal, the method comprising:

detecting with a plurality of different types of noise activity detectors the presence of a plurality of different types of noise in the audio signal, each different type of noise activity detector being adapted to detect a different type of noise;

suppressing the detected type of noise in the audio signal using one of a plurality of different types of noise reduction circuits each adapted for removing a different type of detected noise, where each noise reduction circuit respectively corresponds to one of the plurality of noise activity detectors, when the respective detector detects the presence of the corresponding type of noise by selectively activating the respective noise reduction circuit.