# US 9,521,484 B2 · Multi-beam sound system

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- Number: US 9,521,484 B2
- Document ID: US9521484B2
- Status: Granted
- Kind: B2
- Application number: 13/881,847
- Filed: 2011-10-31
- Published: 2013-08-22
- Granted: 2016-12-13
- Earliest claimed: 2010-10-29
- Assignees: Mightyworks Co., Ltd.
- Applicants: Se Ung Kim
- Inventors: Se Ung Kim
- Web page: https://patentgrep.com/patent/US9521484B2

## CPC

- H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F)
- H04R 3/005: {for combining the signals of two or more microphones (specially adapted for hearing aids H04R25/407)}
- H04R 1/406: {microphones}
- H04R 2201/403: Linear arrays of transducers
- H04R 2430/25: Array processing for suppression of unwanted side-lobes in directivity characteristics, e.g. a blocking matrix
- H04R 2499/13: Acoustic transducers and sound field adaptation in vehicles
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

A multi-beam sound system includes a fixed beamforming section which steers the input signal inputted from the microphone array to an intended direction, a blocking matrix which receives the input signal and acquires a noise reference signal from the input signal, a variable beamforming section which acquires an adaptive noise signal from the noise reference signal outputted from the blocking matrix, and a generalized sidelobe canceller (GSC) which includes canceling means for outputting an object signal from the input signal outputted from the fixed beamforming section by removing the adaptive noise signal from the input signal. The fixed beamforming section steers the input signal in at least two directions.

## Claims

### Claim 1

A multi-beam sound system comprising:
a microphone array disposed at a predetermined position inside a vehicle, the microphone array comprising a plurality of microphones, and configured to generate an input signal; and
an adaptive beamformer configured to form beams of the microphone array,
wherein the adaptive beamformer forms at least two beams of the microphone array in different directions,
wherein the beamformer comprising:
a fixed beamformer configured to process the input signal and generate a fixed beamformer output signal, in which beams are steered to at least two directions;
a blocking matrix configured to receive the input signal and to acquire a noise reference signal from the input signal;
a variable beamformer configured to acquire an adaptive noise signal from the noise reference signal; and
a generalized sidelobe canceller (GSC) configured to output an object signal from the fixed beamformer output signal by removing the adaptive noise signal from the fixed beamformer output signal, and wherein the generalized side lobe canceller (GSC) is designed under constraints according to the following formula:
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### Claim 2 (depends on 1)

The multi-beam sound system according to claim 1, wherein the variable beamformer is configured to acquire the adaptive noise signal using a self-tuning recursive least squares (RLS) algorithm.

### Claim 3 (depends on 1)

The multi-beam sound system according to claim 1, wherein the microphone array is disposed at a predetermined position corresponding to two seats from among seats provided inside the vehicle, wherein
the predetermined position is situated on an orthogonal line which is orthogonal to a line connecting the two seats at a predetermined point between the two seats,
at least one of the at least two beams is formed in a direction facing toward a seat which is positioned on one side with respect to the orthogonal line, and
the other at least one of the at least two beams is formed in a direction facing toward a seat which is positioned on the other side with respect to the orthogonal line.

### Claim 4 (depends on 3)

The multi-beam sound system according to claim 3, further comprising a second microphone array which is disposed so as to correspond to at least one seat from among the seats provided inside the vehicle except for the two seats.

### Claim 5 (depends on 4)

The multi-beam sound system according to claim 4, further comprising a second adaptive beamformer, wherein the adaptive beamformer or the second adaptive beamformer is configured to form at least one beam of the second microphone array.

### Claim 6 (depends on 1)

The multi-beam sound system according to claim 1, further comprising an echo remover is configured to remove an echo signal from the input signal when the echo signal based on a sound signal outputted from an audio-video-navigation (AVN) device of the vehicle is included in the input signal.

### Claim 7 (depends on 6)

The multi-beam sound system according to claim 6, wherein the echo remover is configured to receive information about the sound signal from the audio-video-navigation (AVN) device, to store the received information about the sound signal, to estimate the echo signal based on the stored information about the sound signal, and to remove the estimated echo signal from the input signal.

### Claim 8

A multi-beam sound system comprising:
a fixed beamformer configured to process an input signal from a microphone array and generate a fixed beamformer output signal, in which beams are steered: to at least two directions
a blocking matrix configured to receive the input signal and acquires a noise reference signal from the input signal;
a variable beamformer configured to acquire an adaptive noise signal from the noise reference signal; and
a generalized sidelobe canceller (GSC) configured to output an object signal from the fixed beamformer output signal by removing the adaptive noise signal from the fixed beamformer output signal,
wherein the generalized side lobe canceller (GSC) is designed under constraints according to a following formula in order to steer the beams to at least two directions:
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where Ci indicates an ith constraint matrix, a(θi) indicates a steering vector, w is a weight vector matrix, and f indicates an impulse response that is intended, and N is number of mainlobes.