Hearing Aid Matched Filter for Diffuse Noise Localization

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Solution Overview

Problem

Hearing aid users face difficulties in localizing sound sources and following conversations in noisy environments due to internalized sound reproduction, which leads to listening fatigue and reduced spatial awareness, especially in complex listening situations with diffuse noise.

Innovation Solution

A method involving a microphone system with matched filters that match the sound propagation transfer function, enhancing the signal-to-noise ratio by filtering audio signals to compensate for amplitude and phase changes, and combining signals to improve sound localization while preserving spatial awareness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If directional systems are applied to suppress diffuse noise, then signal-to-noise ratio is improved, but spatial awareness is lost

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidspatial awareness
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies parameter changes by using matched filtering with transfer functions that match the sound propagation path characteristics. This changes the signal processing parameters to enhance the signal-to-noise ratio while preserving spatial information, resolving the contradiction between noise suppression and spatial awareness maintenance.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If hearing aids reproduce sound internally, then speech intelligibility is improved, but cognitive loading increases and listening fatigue occurs

Engineering Contradiction:
Improvespeech intelligibilityVSAvoidlistening duration
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent employs feedback mechanisms through the matched filtering process, where the system continuously adjusts signal processing based on the sound propagation characteristics. This feedback approach maintains speech intelligibility while reducing cognitive loading by optimizing the naturalness of sound reproduction.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple microphones are added to suppress diffuse noise, then noise suppression capability is improved, but device complexity increases

Engineering Contradiction:
Improvenoise suppression capabilityVSAvoidnumber of microphones
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes mechanical approaches (adding more microphones) with signal processing approaches (matched filtering). This replaces the need for additional physical sensors with computational methods that achieve noise suppression through mathematical operations on existing signals.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively improves the signal-to-noise ratio and enhances sound localization, reducing listening fatigue and maintaining environmental awareness in noisy environments, thereby improving the hearing aid user's ability to focus on specific sound sources.

Implementation Method 1

filtering the audio signal with a matched filter having a matching transfer function that matches or substantially matches a transfer function of a sound propagation path

Methodology Applied
Scientific EffectMatched filtering: Filter (electronic)

Data Source

PatentEP3038381B1Diffuse noise listening
Publication Date: 2017.08.09 GN HEARING AS
  • EP3038381B1 patent drawingFigure 1
  • EP3038381B1 patent drawingFigure 2
  • EP3038381B1 patent drawingFigure 3

AI summary

A hearing aid is provided, comprising: a first microphone system configured for conversion of sound emitted by a sound source into a first audio signal, a first matched filter configured for filtering the first audio signal into a first filtered audio signal, the first matched filter having a first matching transfer function that matches a first transfer function of a first sound propagation path of sound propagating from the sound source to the first microphone system providing the first audio signal, when a user wears the hearing aid, and a hearing loss processor configured to provide a hearing loss compensated output signal that compensates for a hearing loss of the user based at least in part on the first filtered audio signal.