# US 2014/0193009 A1 · Method and system for enhancing the intelligibility of sounds relative to background noise

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- Number: US 2014/0193009 A1
- Document ID: US20140193009A1
- Status: Published application
- Kind: A1
- Application number: 13/990,942
- Filed: 2011-12-06
- Published: 2014-07-10
- Earliest claimed: 2010-12-06
- Assignees: Board of Regents, The University of Texas System
- Inventors: Nima Yousefian Jazi; Philipos C. Loizou
- Web page: https://patentgrep.com/patent/US20140193009A1

## CPC

- H04R 25/453: {electronically}
- G10L 21/0208: Noise filtering
- H04R 25/407: {Circuits for combining signals of a plurality of transducers}
- H04R 25/43: {Electronic input selection or mixing based on input signal analysis, e.g. mixing or selection between microphone and telecoil or between microphones with different directivity characteristics (H04R25/407 takes precedence)}
- H04R 2225/43: Signal processing in hearing aids to enhance the speech intelligibility
- 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)
- G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING

## Abstract

A novel dual-microphone speech enhancement technique is proposed that utilizes the coherence function between input signals as a criterion for noise reduction. The technique is based on certain assumptions regarding the spatial properties of the target and noise signals and can be applied to arrays with closely spaced microphones, where noise captured by sensors is highly correlated (e.g., inside a mildly reverberant environment). The proposed algorithm is simple to implement and requires no estimation of noise statistics. In addition, it offers the advantage of coping with situations in which multiple interfering sources located at different azimuths might be present.

## Claims

### Claim 1

A hearing assistance device, comprising: a microphone; and a processor configured to receive signals from the microphone; and wherein the processor is configured to perform noise reduction which adjusts maximum gain reduction as a function of signal-to-noise ratio (SNR), and which reduces the strength of its maximum gain reduction for intermediate signal-to-noise ratio levels to reduce speech distortion.

### Claim 2 (depends on 1)

The device of claim 1, further comprising a memory configured to log noise reduction data for user environments.

### Claim 3 (depends on 2)

The device of claim 2, wherein the processor is configured to use the logged noise reduction data to provide a recommendation to change settings of the noise reduction to decrease speech distortion and improve speech audibility and intelligibility.

### Claim 4 (depends on 2)

The device of claim 2, wherein the processor is configured to use the logged noise reduction data to automatically changing settings of the noise reduction to decrease speech distortion and improve speech audibility and intelligibility.

### Claim 5 (depends on 1)

The device of claim 1, wherein the maximum gain reduction includes a dual microphone noise reduction algorithm (DMNR).

### Claim 6

A method, comprising: receiving signals from a hearing assistance device microphone in user environments; adjusting maximum gain reduction as a function of signal-to-noise ratio to perform noise reduction; and reducing the strength of the maximum gain reduction for intermediate signal-to-noise ratio levels to reduce speech distortion.

### Claim 7 (depends on 6)

The method of claim 6, further comprising logging noise reduction data for the user environments.

### Claim 8 (depends on 7)

The method of claim 7, further comprising providing a recommendation to change settings of the noise reduction based on the logged data to decrease speech distortion and improve speech audibility and intelligibility.

### Claim 9 (depends on 7)

The method of claim 7, further comprising automatically changing settings of the noise reduction based on the logged data to decrease speech distortion and improve speech audibility and intelligibility.

### Claim 10 (depends on 7)

The method of claim 7, wherein logging noise reduction data includes logging which device memories have been used and how often the device memories have been used.

### Claim 11 (depends on 7)

The method of claim 7, wherein logging noise reduction data includes logging average gain reduction during speech plus noise.

### Claim 12 (depends on 7)

The method of claim 7, wherein logging noise reduction data includes logging average gain reduction during noise only.