Hearing Aid AGC Scene Adaptation for Voice Intelligibility
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Solution Overview
Problem
Automatic gain control (AGC) in hearing aids can reduce the signal-to-noise ratio (SNR) and voice intelligibility, especially in loud environments, leading to reduced hearing comfort and voice clarity.
Innovation Solution
A method and hearing aid that adaptively adjust the AGC function based on the current acoustic scene, utilizing a scene recognition unit to set parameters for optimal AGC operation, ensuring the output dynamic range aligns with the user's hearing range and minimizing comb filter effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If automatic gain control (AGC) is applied to amplify low-level signals, then the dynamic range is adjusted and output signal level is controlled, but the signal-to-noise ratio (SNR) is reduced and voice intelligibility deteriorates
Solution Approach 1:
The patent changes the parameters of the AGC function based on the detected acoustic scene. Different acoustic scenes (e.g., quiet environment, noisy environment, speech-dominated) have different AGC parameter settings that optimize both output level control and SNR preservation for each specific scene type.
Solution Approach 2:
The AGC function transitions from a static, fixed configuration to a dynamic one where parameters are automatically adjusted in real-time based on the acoustic scene detection, allowing the system to adapt to varying environmental conditions and optimize performance for each scenario.
2Stability of the object's composition
If compression is applied above the knee point in AGC, then the dynamic range is reduced and output level is stabilized, but voice intelligibility and hearing comfort are reduced in loud environments
Solution Approach 1:
The knee point and compression ratio parameters of the AGC function are adjusted based on the acoustic scene. In loud environments, the knee point is raised or compression is reduced to preserve voice intelligibility and hearing comfort, while in quieter environments, normal compression is applied to maintain output stability.
3Device complexity
If a fixed AGC function is used, then the device complexity is low and operation is simple, but the AGC performance is not optimized for different acoustic scenes
Solution Approach 1:
The hearing aid system performs self-adjustment by automatically detecting the acoustic scene and selecting appropriate AGC parameters without requiring manual user intervention or complex external configuration, thereby maintaining simplicity while achieving scene-specific optimization.
Solution Approach 2:
The system uses acoustic scene detection as feedback to continuously monitor the environment and adjust AGC parameters accordingly, creating a closed-loop control system that adapts to changing acoustic conditions in real-time.
Data Source
AI summary
A method operates a hearing aid which is allocated to a user. The hearing aid receives an audio signal and generates an input signal. From the input signal an automatic gain control (AGC) input signal is generated and is supplied to an AGC unit of the hearing aid. The AGC unit amplifies the AGC input signal depending on a level of the AGC input signal and in accordance with an AGC function and then outputs it as an AGC output signal. The AGC function is defined by one or more parameters which are set depending on an acoustic scene which is currently present. The hearing aid generates, from the AGC output signal, an output signal for output to the user. A hearing device is programmed to perform the method.