Method and device for typing noise removal

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 transient 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 by using spectral subtraction, a noise reduced output signal based on said estimate of said transient keyboard audio noise and said audio signal.

2. 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 transient keyboard audio noise; and

multiplying said audio signal by said gain.

3. 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.

4. The method according to claim 3 ,

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

5. 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.

6. 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.

7. The method according to claim 6 ,

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.

8. 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.

9. The method according to claim 8 , 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 transient keyboard audio noise, and

amplifying said comfort noise signal by said comfort noise gain.

10. 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 transient 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, by using spectral subtraction, based on said estimate of said transient keyboard audio noise and said audio signal.

11. The apparatus of claim 10 , 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 transient keyboard audio noise; and

means for multiplying said audio signal by said gain.

12. 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 transient 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, by using spectral subtraction, based on said estimate of said transient keyboard audio noise and said audio signal.

13. The apparatus according to claim 12 , 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 transient keyboard audio noise, and to multiply said audio signal by said gain.

14. The apparatus according to claim 12 ,

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.

15. The apparatus according to claim 14 ,

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

16. The apparatus according to claim 12 ,

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.

17. The apparatus according to claim 12 , further comprising:

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

18. A non-transitory 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 transient 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 by using spectral subtraction, a noise reduced output signal based on said estimate of said transient keyboard audio noise and said audio signal.

19. The method according to claim 1 , wherein

said detecting includes detecting which key of a plurality of keys on said keyboard is depressed, and

said providing said pre-stored estimate of said transient keyboard audio noise includes selecting from pre-stored data that includes, for each of said plurality of keys on said keyboard, a different pre-stored estimate of a transient noise created by depression of each of said plurality of keys on said keyboard, a pre-stored estimate of a transient noise created by said key detected by said detecting.

20. The apparatus of claim 12 , wherein

said keyboard operation detecting unit detects which key of a plurality of keys on said keyboard is depressed, and

said processor retrieves said pre-stored estimate of said transient keyboard audio noise includes selecting from pre-stored data that includes, for each of said plurality of keys on said keyboard, a different pre-stored estimate of a transient noise created by depression of each of said plurality of keys on said keyboard, a pre-stored estimate of a transient noise created by said key detected by said keyboard operation detecting unit.