Hearing Aid Directional Control That Preserves Off-Axis Speech

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Solution Overview

Problem

Existing hearing aids with adaptive directional functionality struggle to minimize undesired noise without affecting desired signals, especially when desired signals come from directions other than the frontal direction, leading to reduced speech perception and sound quality due to delayed responses and instability in directional characteristic adjustments.

Innovation Solution

A signal processing apparatus with a directional controller and a desired signal detector (DSD) that only adjusts the directional characteristic to minimize output signals when undesired signals are detected, using a control signal to stall adaptation during desired signal presence, ensuring minimal impact on desired signals and maintaining low microphone noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If adaptive directional functionality is used to minimize output signals, then noise reduction is improved, but desired signals from non-frontal directions are suppressed and system stability deteriorates

Engineering Contradiction:

ImprovenoiseVSAvoidspeech perception and sound quality

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The system applies preliminary classification of signals into desired and undesired categories before applying directional processing. By detecting the presence and direction of desired signals in advance, the system prevents suppression of speech from non-frontal directions while still applying noise reduction to identified noise sources.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The hearing aid dynamically adjusts its directional characteristic based on real-time analysis of the acoustic environment. The system transitions between omnidirectional and directional modes, and adjusts the main lobe orientation, based on detected speech directions and noise characteristics, ensuring optimal performance for current conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If omni-directional mode is used for low noise environments, then speech perception from all directions is maintained, but noise suppression capability is reduced

Engineering Contradiction:

Improvespeech perceptionVSAvoidnoise suppression

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system automatically transitions between omnidirectional and directional modes based on the acoustic environment. In low-noise environments or when speech is present, it operates in omnidirectional mode to capture speech from all directions. When noise is dominant and speech direction is identifiable, it switches to directional mode with optimized main lobe orientation for noise suppression.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7933423B2Method for controlling the directionality of the sound receiving characteristic of a hearing aid and a signal processing apparatus

Publication Date: 2011.04.26 WIDEX AS

AI summary

A signal processing apparatus (100) for a hearing aid with a controllable directional characteristic is provided which comprises a directional controller (10) receiving first and second microphone signals (20, 30) and output an output signal (40), a signal analyzer (70) which detects whether at least one of said first and second microphone signals being undesired signals, and wherein said directional controller minimizes the output signal by adjusting the directional characteristic only if the signal analyzer has detected undesired signals.