Headset having a microphone

Abstract

Noise cancelling headsets and a method of improving audio sensitivity for a headset are disclosed. The headset comprises a speaker, a microphone unit comprising at least a first and a second microphone for picking up incoming sound and generating a first audio signal generated at least partly from the at least first microphone and a second audio signal being at least partly generated from the at least second microphone, a signal processor being configured to receive and analyse the first audio signal and the second audio signal to determine one or more equalization filter coefficients, an equalization filter configured to receive the second audio signal and the one or more equalization coefficients, and to equalize the second audio signal according to the determined one or more equalization filter coefficients to provide an output audio signal, wherein the one or more equalization filter coefficient are determined so as to approximate a power spectrum of the output audio signal to a power spectrum of the first audio signal.

1 . A headset for voice communication, having multiple microphones and at least one beam former, the headset comprising
 a speaker,   a microphone unit comprising at least a first and a second microphone for picking up incoming sound and generating a first audio signal generated at least partly from the at least first microphone and a second audio signal being at least partly generated from the at least second microphone,   a signal processor being configured to receive and analyze the first audio signal and the second audio signal, derived from a beam former, to determine one or more equalization filter coefficients,   an equalization filter configured to receive the second audio signal and the one or more equalization coefficients, and to equalize the second audio signal according to the determined one or more equalization filter coefficients to provide an output audio signal, wherein the one or more equalization filter coefficient are determined so as to approximate a power spectrum of the output audio signal to a power spectrum of the first audio signal.   
     
     
         2 . A headset according to  claim 1 , wherein the one or more equalization filter coefficients are determined so that a ratio of the power spectrum of the output audio signal and the power spectrum of the first audio signal approximates a predetermined target ratio. 
     
     
         3 . A headset according to  claim 1 , wherein the one or more equalization filter coefficients are determined from a transfer function, H eq (f)=S 12 (f)/S 22 (f), wherein S 12  denotes a cross-correlation spectrum of the first and second audio signals, and S 22  denotes the autocorrelation spectrum of the second audio signal. 
     
     
         4 . A headset according to  claim 1 , wherein the headset further comprises a microphone boom having at least two microphone openings and connecting the at least two microphone openings to the at least first and second microphones. 
     
     
         5 . A headset according to  claim 1  wherein the second microphone is a noise cancelling microphone. 
     
     
         6 . A headset according to  claim 4 , wherein first and/or second microphones are provided separately in the microphone boom. 
     
     
         7 . A headset according to  claim 1 , wherein the headset comprises a headphone and wherein the signal processor is provided in the headphone. 
     
     
         8 . A headset according to  claim 1 , further comprising a voice activity detector configured to detect when a user is speaking. 
     
     
         9 . A headset according to  claim 8 , wherein the signal processor is configured to analyze the first and second audio signals when a user is speaking. 
     
     
         10 . A headset according to  claim 1 , wherein the equalization filter applies a frequency dependent gain to the second audio signal. 
     
     
         11 . A headset according to  claim 1 , wherein the first audio signal is generated as a weighted sum of audio signals from a plurality of microphones. 
     
     
         12 . A headset according to  claim 1 , wherein the microphone unit comprises at least a first and a second microphone, and wherein a beam former is configured to receive first and/or second microphone output signals and output a first and/or second beam formed signal, respectively. 
     
     
         13 . A headset according to  claim 1 , wherein the first microphone exhibits an omnidirectional frequency response, and/or wherein the second microphone exhibits a noise-cancelled frequency response. 
     
     
         14 . A method of improving audio sensitivity for a headset, the headset comprising a headphone and a microphone unit comprising at least a first and a second microphone and at least one beam former, the method comprising
 generating at least first and second audio signals from the at least first and second microphones   processing the first and second audio signals using at least one beam former, so as to approximate a power spectrum of an output audio signal to a power spectrum of the first audio signal;   receiving an acoustic signal by the at least first and second microphones,   generating a first audio signal and a second audio signal derived from the at least first and second microphones,   analyzing the first and second audio signals to determine one or more equalization filter coefficients,   equalizing the second audio signal according to the determined one or more equalization filter coefficients to provide an output audio signal, wherein the one or more equalization filter coefficients are determined so as to approximate a power spectrum of the output audio signal to a power spectrum of the first audio signal.   
     
     
         15 . A method according to  claim 14 , wherein the one or more equalization filter coefficients are determined so as to approximate a power spectrum of the output audio signal to a power spectrum of the first audio signal. 
     
     
         16 . A method according to  claim 14 , wherein the step of analyzing the first and second audio signals comprises a transformation of the first and second audio signals to the frequency domain, determining an equalization function H eq (f) by analysing analyzing the first audio signal and the second audio signal in a signal processor,
 and deriving the equalization function as H eq (f)=S 12 (f)/S 22 (f), wherein S 12  denotes a cross-correlation spectrum of the first and second audio signals, and S 22  denotes the autocorrelation spectrum of the second audio signal.   
     
     
         17 . A headset for voice communication, the headset having at least two microphones and at least one beam former, comprising
 a speaker,   a microphone unit comprising at least a first and a second microphone for picking up incoming sound and generating a first audio signal generated at least partly from the at least first microphone and a second audio signal being at least partly generated from the at least second microphone,   a signal processor including at least one beam former, being configured to receive and analyze the first audio signal and the second audio signal to determine one or more equalization filter coefficients,   an equalization filter configured to receive the second audio signal and the one or more equalization coefficients, and to equalize the second audio signal according to the determined one or more equalization filter coefficients to provide an output audio signal, wherein the one or more equalization filter coefficient are determined so as to approximate a power spectrum of the output audio signal to a power spectrum of the first audio signal and further including voice activity detector configured to detect when a user is speaking.