Binaural Hearing Aid Automatic Microphone Mode Switching

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Solution Overview

Problem

Current hearing aids require manual switching between omnidirectional (OMNI) and directional (DIR) microphone modes, which can be inconvenient and lead to suboptimal performance in dynamic listening environments, as users may not switch modes frequently enough or may leave devices in default OMNI mode, missing out on DIR processing benefits.

Innovation Solution

A method that monitors spectral and temporal modulations of input signals from binaural microphone systems to predict user preferences, calculating an evaluation index (EI) to automatically switch between OMNI and DIR modes, allowing for asymmetric bilateral processing to enhance speech intelligibility by focusing on relevant signals and inhibiting noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If manual switching between OMNI and DIR modes is implemented, then users can select appropriate processing modes, but users may not switch modes frequently enough or leave devices in default OMNI mode, resulting in suboptimal performance in dynamic listening environments

Engineering Contradiction:
Improveadaptability to different listening conditionsVSAvoidconvenience of mode switching
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system dynamically switches between OMNI and DIR processing modes based on real-time analysis of acoustic environment characteristics, rather than requiring manual user intervention. The hearing aid automatically adapts to changing listening conditions by monitoring spectral and temporal modulations and adjusting the microphone processing mode accordingly.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hearing aid performs self-service by automatically analyzing the acoustic environment and selecting the appropriate processing mode without user input. The device monitors its own input signals, evaluates spectral and temporal modulations, and autonomously switches between OMNI and DIR modes to optimize speech intelligibility in varying listening conditions.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If automatic switching between OMNI and DIR modes is implemented, then the hearing aid can dynamically adapt to acoustic environment, but the system complexity increases due to spectral and temporal modulation analysis

Engineering Contradiction:
Improveautomatic adaptation to listening conditionsVSAvoidcomplexity of signal processing system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system extracts specific diagnostic features (spectral and temporal modulations) from the full acoustic signal to determine the appropriate processing mode. By focusing on these key modulations rather than analyzing the entire signal spectrum continuously, the system achieves automatic adaptation with reduced computational complexity compared to full spectral analysis approaches.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system changes processing parameters (microphone mode selection) based on detected spectral and temporal modulation characteristics of the input signal. By monitoring specific parameter changes in the acoustic environment and responding with discrete mode switches between OMNI and DIR processing, the system achieves adaptability without requiring continuously variable complex processing.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If directional processing is used in noisy environments, then signal-to-noise ratio is improved for front-facing signals, but access to sounds from surrounding environment is reduced

Engineering Contradiction:
Improvesignal-to-noise ratio in noiseVSAvoidaccess to environmental sounds
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system dynamically selects between OMNI and DIR processing modes based on the acoustic environment. In noisy conditions with front-facing speech signals, DIR mode provides improved signal-to-noise ratio. In quiet conditions or when spatial awareness is needed, OMNI mode provides access to sounds from all directions. The system switches between these states to optimize both SNR and environmental awareness as conditions change.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system periodically evaluates spectral and temporal modulations of the input signal to determine when to switch between OMNI and DIR modes. This periodic analysis allows the system to alternate between broad environmental monitoring (OMNI) and focused noise rejection (DIR) based on the current acoustic scene, balancing information access with signal clarity in varying conditions.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2897386B2Automatic switching between omnidirectional and directional microphone modes in a hearing aid
Publication Date: 2021.08.04 GN HEARING AS
  • EP2897386B2 patent drawingFigure 1
  • EP2897386B2 patent drawingFigure 2
  • EP2897386B2 patent drawingFigure 3

AI summary

The present invention pertains to a method of automatic switching between omnidirectional (OMNI) and directional (DIR) microphone modes in a binaural hearing aid comprising a first microphone system for the provision of a first input signal, a second microphone system for the provision of a second input signal, where the first microphone system is adapted to be placed in or at a first ear of a user, the second microphone system is adapted to be placed in or at a second ear of said user, the method comprising a measurement step, where the spectral and temporal modulations of the first and second input signal are monitored, an evaluation step, where the spectral and temporal modulations of the first and second input signal are evaluated by the calculation of an evaluation index of speech intelligibility for each of said signals, and an operational step, where the microphone mode of the first and the second microphone systems of the binaural hearing aid are selected in dependence of the calculated evaluation indexes.