摘要:
The application relates to an audio processing device comprising a) at least one input unit for providing time-frequency representation Y(k,n) of an electric input signal representing a time variant sound signal consisting of target speech signal components S(k,n) from a target sound source TS and noise signal components N(k,n) from other sources than the target sound source, where k and n are frequency band and time frame indices, respectively, b) a noise detection and/or reduction system configured to b1) determine an a posteriori signal to noise ratio estimate γ(k,n) of said electric input signal, and to b2) determine an a priori target signal to noise signal ratio estimate ζ(k,n) of said electric input signal from said a posteriori signal to noise ratio estimate γ(k,n) based on a recursive decision directed algorithm. The a priori target signal to noise signal ratio estimate ζ(k,n) for the n th timeframe is determined from the a priori target signal to noise signal ratio estimate ζ(k,n-1) for the (n-1) th timeframe and the a posteriori signal to noise ratio estimate γ(k,n) for the n th timeframe. The application further relates to a method of of estimating an a priori signal to noise ratio. Thereby improved noise reduction may be provided. The invention may e.g. be used for the hearing aids, headsets, ear phones, active ear protection systems, handsfree telephone systems, mobile telephones, etc.
摘要:
The invention relates to a communication device having at least two microphones, where in order to match the microphone performance in respect of the phase response a correction filter in the form of a IIR filter is implemented and where the amplitude of the transfer function for the correction filter is the inverse of the difference between the two microphone amplitudes.
摘要:
The application relates to a method for audio signal processing. The application further relates to a method of processing signals obtained from a multi-microphone system. The object of the present application is to reduce undesired noise sources and residual echo signals from an initial echo cancellation step. The problem is solved by receiving M communication signals in frequency subbands where M is at least two; processing the M subband communication signals in each subband with a blocking matrix ( 203,303,403 ) of M rows and N linearly independent columns in each subband, where N >=1 and N , to obtain N target-cancelled signals in each subband; processing the M subband communication signals and the N target-cancelled signals in each subband with a set of beamformer coefficients ( 204,304,404 ) to obtain a beamformer output signal in each subband; processing the communication signals with a target absence detector ( 309 ) to obtain a target absence signal in each subband; using the target absence signal to obtain an inverse target-cancelled covariance matrix of order N ( 310,410 ) in each band; processing the N target-cancelled signals in each subband with the inverse target-cancelled covariance matrix in a quadratic form ( 312, 412 ) to yield a real-valued noise correction factor in each subband; using the target absence signal to obtain an initial estimate ( 311, 411 ) of the noise power in the beamformer output signal averaged over recent frames with target absence in each subband; multiplying the initial noise estimate with the noise correction factor to obtain a refined estimate ( 417 ) of the power of the beamformer output noise signal component in each subband; processing the refined estimate of the power of the beamformer output noise signal component with the magnitude of the beamformer output to obtain a postfilter gain value in each subband; processing the beamformer output signal with the postfilter gain value ( 206,306,406 ) to obtain a postfilter output signal in each subband; processing the postfilter output subband signals through a synthesis filterbank ( 207,307,407 ) to obtain an enhanced beamformed output signal where the target signal is enhanced by attenuation of noise signal components. This has the advantage of providing improved sound quality and reduction of undesired signal components such as the late reverberant part of an acoustic echo signal. The invention may e.g. be used for headsets, hearing aids, active ear protection systems, mobile telephones, teleconferencing systems, karaoke systems, public address systems, mobile communication devices, hands-free communication devices, voice control systems, car audio systems, navigation systems, audio capture, video cameras, and video telephony.
摘要:
The application relates to a method for audio signal processing. The application further relates to a method of processing signals obtained from a multi-microphone system. The object of the present application is to reduce undesired noise sources and residual echo signals from an initial echo cancellation step. The problem is solved by receiving M communication signals in frequency subbands where M is at least two; processing the M subband communication signals in each subband with a blocking matrix ( 203,303,403 ) of M rows and N linearly independent columns in each subband, where N >=1 and N
摘要:
The invention relates to a communication device having at least two microphones, where in order to match the microphone performance in respect of the phase response a correction filter in the form of a IIR filter is implemented and where the amplitude of the transfer function for the correction filter is the inverse of the difference between the two microphone amplitudes.
摘要:
The application relates to a method for audio signal processing. The application further relates to a method of processing signals obtained from a multi-microphone system. The object of the present application is to reduce undesired noise sources and residual echo signals from an initial echo cancellation step. The problem is solved by receiving M communication signals in frequency subbands where M is at least two; processing the M subband communication signals in each subband with a blocking matrix (203,303,403) of M rows and N linearly independent columns in each subband, where N >=1 and N to obtain N target-cancelled signals in each subband; processing the M subband communication signals and the N target-cancelled signals in each subband with a set of beamformer coefficients (204,304,404) to obtain a beamformer output signal in each subband; processing the communication signals with a target absence detector (309) to obtain a target absence signal in each subband; using the target absence signal to obtain an inverse target-cancelled covariance matrix of order N (310,410) in each band; processing the N target-cancelled signals in each subband with the inverse target-cancelled covariance matrix in a quadratic form (312, 412) to yield a real-valued noise correction factor in each subband; using the target absence signal to obtain an initial estimate (311, 411 ) of the noise power in the beamformer output signal averaged over recent frames with target absence in each subband; multiplying the initial noise estimate with the noise correction factor to obtain a refined estimate (417) of the power of the beamformer output noise signal component in each subband; processing the refined estimate of the power of the beamformer output noise signal component with the magnitude of the beamformer output to obtain a postfilter gain value in each subband; processing the beamformer output signal with the postfilter gain value (206,306,406) to obtain a postfilter output signal in each subband; processing the postfilter output subband signals through a synthesis filterbank (207,307,407) to obtain an enhanced beamformed output signal where the target signal is enhanced by attenuation of noise signal components. This has the advantage of providing improved sound quality and reduction of undesired signal components such as the late reverberant part of an acoustic echo signal. The invention may e.g. be used for headsets, hearing aids, active ear protection systems, mobile telephones, teleconferencing systems, karaoke systems, public address systems, mobile communication devices, hands-free communication devices, voice control systems, car audio systems, navigation systems, audio capture, video cameras, and video telephony.
摘要:
The application relates to an audio processing device comprising a) at least one input unit for providing time-frequency representation Y(k,n) of an electric input signal representing a time variant sound signal consisting of target speech signal components S(k,n) from a target sound source TS and noise signal components N(k,n) from other sources than the target sound source, where k and n are frequency band and time frame indices, respectively, b) a noise detection and/or reduction system configured to b1) determine an a posteriori signal to noise ratio estimate γ(k,n) of said electric input signal, and to b2) determine an a priori target signal to noise signal ratio estimate ζ(k,n) of said electric input signal from said a posteriori signal to noise ratio estimate γ(k,n) based on a recursive decision directed algorithm. The a priori target signal to noise signal ratio estimate ζ(k,n) for the n th timeframe is determined from the a priori target signal to noise signal ratio estimate ζ(k,n-1) for the (n-1) th timeframe and the a posteriori signal to noise ratio estimate γ(k,n) for the n th timeframe. The application further relates to a method of of estimating an a priori signal to noise ratio. Thereby improved noise reduction may be provided. The invention may e.g. be used for the hearing aids, headsets, ear phones, active ear protection systems, handsfree telephone systems, mobile telephones, etc.
摘要:
The application relates to a method of providing a speech intelligibility predictor value for estimating an average listener's ability to understand of a target speech signal when said target speech signal is subject to a processing algorithm and/or is received in a noisy environment. The application further relates to a method of improving a listener's understanding of a target speech signal in a noisy environment and to corresponding device units. The object of the present application is to provide an alternative objective intelligibility measure, e.g. a measure that is suitable for use in a time-frequency environment. The invention may e.g. be used in audio processing systems, e.g. listening systems, e.g. hearing aid systems.