Steering vector estimation for minimum variance distortionless response (MVDR) beamforming circuits, systems, and methods
A method of estimating a steering vector of a sensor array of M sensors according to one embodiment of the present disclosure includes estimating a steering vector of a noise source located at an angle θ degrees from a look direction of the array using a least squares estimate of the gains of the sensors in the array, defining a steering vector of a desired sound source in the look direction of the array, and estimating the steering vector by performing element-by-element multiplication of the estimated noise vector and the complex conjugate of steering vector of the desired sound source. The sensors may be microphones.
1. A method of estimating a steering vector of a sensor array including M sensors, the method comprising:
estimating a first steering vector of a noise source located at an angle θ degrees from a look direction of the sensor array using a least squares estimate of the gains of the M sensors in the sensor array;
defining a second steering vector of a desired source in the look direction of the sensor array; and
estimating the steering vector of the sensor array by performing element-by-element multiplication of the estimated first steering vector and the complex conjugate of second steering vector of the desired source.
2. The method of claim 1 , wherein the sensor array comprises a microphone array of M microphones.
3. The method of claim 2 , wherein the complex conjugate of the gain of the ith sensor in the sensor array including M sensors is estimated using least squares as follows:
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H
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X
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X
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where X i (f) is an input vector for the ith microphone in the fth frequency bin and X 0 (f) is the input vector for the 0 th sensor of the M sensors of the sensor array.
4. An electronic system, comprising:
a sensor array including a plurality of sensors, each sensor having an associated gain and being configured to generate a respective electrical signals responsive to an incident wave;
a beamformer circuit coupled to the microphone array to receive the respective electrical signals from the plurality of sensors, the beamformer circuit configured to estimate a steering vector of the sensor array from an element-by-element multiplication of an estimated noise vector and the complex conjugate of a second steering vector of a desired source in a look direction of the sensor array, the beamformer circuit configured to estimate the noise vector from a least squares estimate of the gains of the plurality of sensors for a noise source located at an angle θ degrees from the look direction of the sensor array; and
an electronic device coupled to the beamformer circuit.
5. The electronic system of claim 4 , wherein the sensor array comprises a plurality of microphones, each microphone configured to generate a respective electrical signal responsive to an incident acoustical wave.
6. The electronic system of claim 5 , wherein the electronic device comprises an audio/visual system.
7. The electronic system of claim 5 , wherein the beamformer circuit is configured to calculate the complex conjugate of the gain of the ith sensor in the sensor array through least squares as:
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H
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X
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where X i (f) is an input vector for the ith microphone in the fth frequency bin and X 0 (f) is the input vector for the 0 th sensor of the plurality of sensors of the sensor array.