ROBUST ADAPTIVE BEAMFORMING WITH ENHANCED NOISE SUPPRESSION
First Claim
1. A computer-implemented process for improving the signal to noise ratio of one or more signals from sensors of a sensor array, comprising:
- inputting signals of sensors of a sensor array in the frequency domain defined by frequency bins and a time frame index;
computing a beamformer output as function of the input signals divided into k frequency bins and the time frame index;
estimating a desired signal by taking the product of the beamformer output and the probability that the beamformer output contains the desired signal at a given target angle region;
using the estimated desired signal as a reference signal and subtracting components that are correlated to the estimated desired signal from the input signals to obtain interference signals;
subtracting the interference signals from the beamformer output to produce an output signal with an increased signal to noise ratio.
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Accused Products
Abstract
A novel adaptive beamforming technique with enhanced noise suppression capability. The technique incorporates the sound-source presence probability into an adaptive blocking matrix. In one embodiment the sound-source presence probability is estimated based on the instantaneous direction of arrival of the input signals and voice activity detection. The technique guarantees robustness to steering vector errors without imposing ad hoc constraints on the adaptive filter coefficients. It can provide good suppression performance for both directional interference signals as well as isotropic ambient noise.
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Citations
20 Claims
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1. A computer-implemented process for improving the signal to noise ratio of one or more signals from sensors of a sensor array, comprising:
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inputting signals of sensors of a sensor array in the frequency domain defined by frequency bins and a time frame index; computing a beamformer output as function of the input signals divided into k frequency bins and the time frame index; estimating a desired signal by taking the product of the beamformer output and the probability that the beamformer output contains the desired signal at a given target angle region; using the estimated desired signal as a reference signal and subtracting components that are correlated to the estimated desired signal from the input signals to obtain interference signals; subtracting the interference signals from the beamformer output to produce an output signal with an increased signal to noise ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer-implemented process for improving the signal to noise ratio of one or more signals from sensors of a sensor array, comprising:
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inputting signals from microphones of a microphone array in the frequency domain; computing a beamformer output; computing a speech presence probability that speech exists in a given frequency bin; computing the spatial probability that sound is coming from a given angular direction; computing the probability that a desired signal is coming from a given direction using the spatial probability, the speech presence probability and the beamformer output; applying a set of adaptive filters of an adaptive blocking matrix to determine interference in the input signals using the probability that the desired signal is coming from a given direction; applying an adaptive interference canceller to cancel the interference signals from the beamformer output; and outputting the beamformer output with an enhanced signal to noise ratio. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system for improving the signal to noise ratio of a signal received from a microphone array, comprising:
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a general purpose computing device; a computer program comprising program modules executable by the general purpose computing device, wherein the computing device is directed by the program modules of the computer program to, capture audio signals in the time domain with a microphone array; convert the time-domain signals xi(n) to frequency-domain using a converter; input the signals in the frequency domain into a beamformer and computing a beamformer output wherein the beamformer output represents the optimal solution for capturing an audio signal at a target point using the total microphone array input; estimate a desired signal by taking the product of the beamformer output Yfl(k) and the probability Pl(k) that the beamformer output Yfl(k) contains the desired signal originating from a target region; use the estimated desired signal Ysl(k) as a reference signal and adaptively subtract the components that are correlated to the estimated desired signal Ysl(k) from the input signals in the frequency domain using an adaptive blocking matrix to obtain the interference portion of the input signals; update the adaptive filter coefficients Bil(k) of the adaptive blocking matrix; and remove the signal components in the beamformer output Yfl(k) that are correlated to the interference signals by using an adaptive interference canceller to output an enhanced beamformer output. - View Dependent Claims (18, 19, 20)
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Specification