METHOD AND DEVICE FOR TYPING NOISE REMOVAL

• US 20100027810A1
• Filed: 06/30/2009
• Published: 02/04/2010
• Est. Priority Date: 06/30/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Tandberg Telecom AS (Cisco Systems, Inc.)
• Inventors: Marton, Trygve F.
• Granted Patent: US 8,295,502 B2
• Time in Patent Office: Days
• US Class Current: 381/94.100
• CPC Class Codes: G10L 21/0208 Noise filtering
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q

Abstract

A method for reducing keyboard noise in conferencing equipment which includes a microphone and a keyboard, the method including: providing, at a noise reduction apparatus, an audio signal originating from the microphone; detecting, at the noise reduction apparatus, an operation of the keyboard; providing, at the noise reduction apparatus, a pre-stored estimate of a keyboard audio noise resulting from the operation of the keyboard upon detection of the operation of the keyboard; and calculating, at the noise reduction apparatus, a noise reduced output signal based on the estimate of the keyboard audio noise and the audio signal.

Claims

1. A method for reducing keyboard noise in conferencing equipment which includes a microphone and a keyboard, the method comprising:

providing, at a noise reduction apparatus, an audio signal originating from said microphone;

detecting, at the noise reduction apparatus, an operation of said keyboard;

providing, at the noise reduction apparatus, a pre-stored estimate of a keyboard audio noise resulting from said operation of said keyboard upon detection of said operation of said keyboard; and

calculating, at the noise reduction apparatus, a noise reduced output signal based on said estimate of said keyboard audio noise and said audio signal.

2. The method according to claim 1,

wherein said calculating of said noise reduced output signal comprises implementing spectral subtraction.

3. The method according to claim 1, wherein said calculating the noise reduced output signal comprises:

calculating a gain, based on said audio signal and said pre-stored estimate of said keyboard audio noise; and

multiplying said audio signal by said gain.

4. The method according to claim 1,

wherein said providing the pre-stored estimate includes selecting the pre-stored estimate from pre-stored data based on an identification of a key operated on said keyboard.

5. The method according to claim 4,

wherein said pre-stored table is pre-generated by training.

6. The method according to claim 1,

wherein said providing the audio signal originating from said microphone comprises providing the audio signal as a digital audio signal, amplifying, filtering, sampling and digitizing the audio signal originating from said microphone.

7. The method according to claim 1,

wherein said step of providing the audio signal is followed by a dividing the audio signal into frequency sub bands.

8. The method according to claim 7,

wherein said dividing includes configuring the frequency sub bands in accordance with a scale selected from a group including:

a uniform scale, a logarithmic scale, and a psychoacoustic.

9. The method according to claim 1, wherein said calculating the noise reduced output signal comprises:

generating a comfort noise signal, and

adding said comfort noise signal to said noise reduced output signal.

10. The method according to claim 9, wherein said step of adding said comfort noise signal comprises:

calculating a comfort noise gain, based on said audio signal and said estimate of said keyboard audio noise, and

amplifying said comfort noise signal by said comfort noise gain.

11. A noise reduction apparatus configured to reduce keyboard noise in conferencing equipment which includes a microphone and a keyboard, the noise reduction apparatus comprising:

means providing an audio signal originating from said microphone;

means for detecting an operation of said keyboard;

means for providing a pre-stored estimate of a keyboard audio noise resulting from said operation of said keyboard upon detection of said operation of said keyboard; and

means for calculating a noise reduced output signal based on said estimate of said keyboard audio noise and said audio signal.

12. The apparatus of claim 11, wherein said means for calculating the noise reduced output signal comprises:

means for calculating a gain, based on said audio signal and said pre-stored estimate of said keyboard audio noise; and

means for multiplying said audio signal by said gain.

13. A noise reduction apparatus configured to reduce keyboard noise in conferencing equipment which includes a microphone and a keyboard, the noise reduction apparatus comprising:

a receiver configured to receive an audio signal originating from said microphone;

a keyboard operation detecting unit configured to detect an operation of said keyboard; and

a processor configured to retrieve a pre-stored estimate of a keyboard audio noise resulting from said operation of said keyboard from a memory device upon detection of said operation of said keyboard, and to calculate a noise reduced output signal based on said estimate of said keyboard audio noise and said audio signal.

14. The apparatus according to claim 13,

wherein said processor is configured to used spectral subtraction in calculating said noise reduced output signal.

15. The apparatus according to claim 13, wherein said processor is configured to calculate the noise reduced output signal by calculating a gain, based on said audio signal and said pre-stored estimate of said keyboard audio noise, and to multiply said audio signal by said gain.

16. The apparatus according to claim 13,

wherein said processor is configured to select the pre-stored estimate from pre-stored data based on an identification of a key operated on said keyboard.

17. The apparatus according to claim 16,

wherein said pre-stored table is pre-generated by training.

18. The apparatus according to claim 13,

wherein said receiver is configured to output the audio signal as a digital audio signal, and to amplify, filter, sample and digitize the audio signal originating from said microphone.

19. The apparatus according to claim 13, further comprising:

a frequency band divider unit configure to divide said audio signal received by the receiver frequency sub bands.

20. A computer readable storage medium encoded with instructions, which when executed by a noise reduction apparatus causes the noise reduction apparatus to implement a method for reducing keyboard noise in conferencing equipment which includes a microphone and a keyboard, the method comprising:

providing, at the noise reduction apparatus, an audio signal originating from said microphone;

detecting, at the noise reduction apparatus, an operation of said keyboard;

providing, at the noise reduction apparatus, a pre-stored estimate of a keyboard audio noise resulting from said operation of said keyboard upon detection of said operation of said keyboard; and

calculating, at the noise reduction apparatus, a noise reduced output signal based on said estimate of said keyboard audio noise and said audio signal.