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Beam Former Adjustments Based on Recipient Movement

IP.com Disclosure Number: IPCOM000239387D
Publication Date: 2014-Nov-04
Document File: 4 page(s) / 99K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a system that utilizes an accelerometer to extend the capabilities of a beam former in a bilateral hearing device and improve hearing for the user. The system detects wearer movements and accordingly responds to adjust the width or direction of the beam former as well as the sound capture modes of the hearing device.

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Title 

Beam Former Adjustments Based on Recipient Movement

Abstract

Disclosed is a system that utilizes an accelerometer to extend the capabilities of a beam former in a bilateral hearing device and improve hearing for the user.  The system detects wearer movements and accordingly responds to adjust the width or direction of the beam former as well as the sound capture modes of the hearing device.

Problem Addressed 

Many hearing device recipients have problems hearing in environments with a high amount of background or ambient sound, which creates noise. One solution is a beam former, which picks up sound that is directly in front of the user while reducing sounds arriving from other directions. This helps the user select a sound source on which to focus listening.

A common issue with the beam former is that the beam might be too narrow to capture all speakers in a conversation. As the user moves their head back and forth, the speaker goes in and out of focus; thus, the problem of not being able to hear well remains.

 

When using bilateral hearing devices, a current approach to enhance hearing uses phase differential to adjust the beam former. This changes the width of the beam depending on the modulation of the phase difference of correlated signals when the signals of the two devices have high coherence. This method projects a narrow beam if the talker and wearer are standing still and projects a wider beam when the head is moving. In combination with the phase difference of the signal coming from the same sound source, the approach can use a level difference. When the user’s head moves away from the sound source a phase difference is created, and the side facing away from the sound source receives a lower level of input.  The sound arrives later to the device phasing away from the speaker.  This is applicable to any moving sound source such as a sound in a movie theatre, a car passing, etc.


Figure 1: Differences in beam projection based on phase difference of correlated signals

Novelty Statement

The novel contribution is a system that adds an accelerometer to extend the capabilities of the beam former in bilateral hearing devices.  The accelerometer detects when the user moves their head. In response to detected movement, the device changes the width or direction of the beam former to encompass the speaker and maximize hearing for the wearer. In addition, in response to back-and-forth movement of the user’s head, which indicates a three-way conversation, the system widens the device beam to include two speakers in the range of the microphone.  Further, the system can smoothly exit the widened mode and return the directional microphone to the previous directi...