Northwestern Polytechnical University

Huawei Technologies Co., Limited

Jingdong Chen

Gongping Huang

Jacob Benesty

Jilu Jin

Haiting Li

Deming Zhang

Chao Pan

Yuzhu Wang

Xueqin Luo

Xudong Zhao

Xuehan Wang

A concentric circular microphone array (CCMA) may include a number of omnidirectional microphones and an equal number of directional microphones, wherein the omnidirectional microphones and the directional microphones form a plurality of concentric rings on a substantially planar platform. Each of the plurality of concentric rings includes a subset of the omnidirectional microphones and a subset of the directional microphones (e.g., arranged in mixed pairs of microphones). Responsive to a sound source, the omnidirectional microphones and the directional microphones may respectively generate first and second electronic signals. A target beampattern of Norder may be specified for the CCMA. An Norder beamformer for the CCMA, that is steerable in a three-dimensional space including the sound source, may be determined based on the specified target beampattern. The beamformer may be executed to calculate an estimate of the sound source based on the first electronic signals and the second electronic signals.

Concentric circular microphone arrays with 3D steerable beamformers

A beamformer, for a differential microphone array (DMA) including a number M of microphones, is constructed based on a specified target directivity factor (DF) value for the DMA. An N order beampattern is generated for the DMA, wherein N is an integer and a first DF value corresponding to the N order beampattern is greater than the target DF value. An N−1 order beampattern is generated for the DMA, wherein a second DF value corresponding to the N−1 order beampattern is greater than the target DF value. A fractional order beampattern is generated for the DMA, wherein a third DF value corresponding to the fractional order beampattern matches the target DF value and the fractional order beampattern comprises a first fractional contribution from the N order beampattern and a second fractional contribution from the N−1 order beampattern.

Flexible differential microphone arrays with fractional order

A binaural beamformer comprising two beamforming filters may be communicatively coupled to a microphone array to generates two beamforming outputs, one for the left ear and the other for the right ear. The beamforming filters may be configured in such a way that they are orthogonal to each other to make white noise components in the binaural outputs substantially uncorrelated and desired signal components in the binaural outputs highly correlated. As a result, the human auditory system may better separate the desired signal from white noise and intelligibility of the desired signal may be improved.

Binaural beamforming microphone array

An Norder linear differential microphone array (LDMA) with a steerable beamformer may be constructed by specifying a target beampattern for the LDMA at a steering angle &#x3b8;. An Norder polynomial associated with the target beampattern may then be generated. A relationship between the nulls of the polynomial and the steering angle &#x3b8; is determined and then a value of one of the nulls is determined based on N&#x2212;1 assigned values for the other nulls and the determined relationship between the nulls of the polynomial and the steering angle &#x3b8;. The steerable beamformer may be generated based on the determined null value and the N&#x2212;1 assigned null values. The N&#x2212;1 assigned null values may be associated with the N&#x2212;1 nulls of the polynomial that are of less than Norder and the determined null value may be associated with the null of the polynomial that is of Norder.

Linear differential microphone arrays with steerable beamformers

A differential microphone array includes a plurality of microphones situated on a substantially planar platform and a processing device, communicatively coupled to the plurality of microphones, to receive a plurality of electronic signals generated by the plurality of microphones responsive to a sound source and execute a minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals, wherein the minimum-norm beamformer is determined subject to a constraint that an approximation of a beampattern associated with the differential microphone array substantially matches a target beampattern.

Flexible geographically-distributed differential microphone array and associated beamformer

An Norder linear differential microphone array (LDMA) including at most M microphones, where M is greater than N, is constructed by identifying a number K of combinations of at least (N+1) of the M microphones. A target cost function is specified based on at least one of a directivity factor, a beampattern, or a white noise gain associated with the LDMA. For each frequency band of a plurality of frequency bands: an optimal combination of microphones, from the K combinations, is determined based on an evaluation of the target cost function for the band and beamforming is performed using the determined optimal combination for the band. A union of the optimal combinations of microphones for the plurality of bands may be determined and the LDMA may be constructed, using microphones in the union, based on an evaluation of the target cost function across the plurality of bands.

Linear differential microphone arrays based on geometric optimization

A multi-ringed differential microphone array includes a first number of microphones situated along a first substantial circle having a first radius, a second number of microphones situated along a second substantial circle having a second radius, and a processing device, communicatively coupled to the first number microphones and the second number of microphones, to receive a plurality of electronic signals generated by the first number of microphones and the second number of microphones, determine a differential order (N) based on the second number, and execute an N-th order minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals.

Frequency-invariant beamformer for compact multi-ringed circular differential microphone arrays

A differential microphone array includes a plurality of microphones situated on a substantially planar platform, the plurality of microphones including a total number (M) of microphones and at least two subsets of the plurality of microphones situated along at least two substantially concentric ellipses with respect to a center, and a processing device, communicatively coupled to the plurality of microphones, to receive a plurality of electronic signals generated by the plurality of microphones responsive to a sound source and execute a minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals, in which the minimum-norm beamformer has a differential order (N), and wherein M&#x3e;N+1.

Concentric circular differential microphone arrays and associated beamforming

A differential microphone array includes a number (M) of microphone sensors for converting sound to a number of electrical signals, and a processor, operably coupled to the microphone sensors, to specify a target differential order (N) for the differential microphone array, and wherein M&#x3e;N+1, specify a steering matrix D comprising N+1 steering vectors, calculate a respective one of a plurality of linearly specify a steering matrix D comprising N+1 steering vectors-constrained minimum variance filters based on the steering matrix, apply the respective one of the plurality of linearly-constrained minimum variance filters to a respective one of the electrical signals to calculate a respective frequency response of the electrical signals, wherein the respective frequency response comprises a plurality of components associated with a plurality of subbands, and sum the frequency responses of the electrical signals with respect to each subband to calculate an estimated frequency spectrum of the sound.

Low noise differential microphone arrays

A system and method relate to receiving, by a processing device, a plurality of sound signals captured at a plurality of microphone sensors, wherein the plurality of sound signals are from a sound source, and wherein a number (M) of the plurality of microphone sensors is greater than three, determining a number (K) of layers for a multistage minimum variance distortionless response (MVDR) beamformer based on the number (M) of the plurality of microphone sensors, wherein the number (K) of layers is greater than one, and wherein each layer of the multistage MVDR beamformer comprises one or more mini-length MVDR beamformers, and executing the multistage MVDR beamformer to the plurality of sound signals to calculate an estimate of the sound source.

Multistage minimum variance distortionless response beamformer

A sound signal processing method and apparatus are provided that relate to the audio signal processing field. The method in the present invention includes acquiring, by a mobile terminal, sound signals from a three-dimensional sound field, where at least three microphones are disposed on the mobile terminal and one microphone is configured to receive a sound signal in at least one direction; acquiring, according to the acquired sound signals, a direction of a sound source relative to the mobile terminal; and obtaining spatial audio signals according to the direction of the sound source relative to the mobile terminal and the acquired sound signals, where the spatial audio signals are used for simulating the three-dimensional sound field. The present invention is applicable to a process of collecting and processing signals in a three-dimensional sound field surrounding a terminal.

Sound signal processing method and apparatus

A differential microphone array (DMA) is provided that includes a number (M) of microphone sensors for converting a sound to a number of electrical signals and a processor that is configured to apply linearly-constrained minimum variance filters on the electrical signals over a time window to calculate frequency responses of the electrical signals over a plurality of subbands and sum the frequency responses of the electrical signals for each subband to calculate an estimated frequency spectrum of the sound.

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Shanxi, China

Jingdong Chen