Hearing Aid Noise Reduction via SNR-Dependent Gain Control
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Solution Overview
Problem
Modern hearing assistance devices face challenges in noise reduction, as existing noise reduction algorithms often result in speech distortion, leading to decreased intelligibility and audibility of speech, particularly in varying acoustic environments.
Innovation Solution
A hearing assistance device with a processor that adjusts maximum gain reduction based on signal-to-noise ratio (SNR) and logs noise reduction data to optimize noise reduction settings, reducing speech distortion by varying gain reduction levels and automatically adjusting settings based on user environment data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise reduction algorithms are applied in hearing assistance devices, then noise reduction is improved, but speech intelligibility and audibility deteriorate due to speech distortion
Solution Approach 1:
The patent changes the parameter of maximum gain reduction from a fixed value to a variable that depends on the signal-to-noise ratio (SNR). By adjusting the maximum gain reduction parameter based on SNR conditions, the system achieves adaptive noise reduction that preserves speech quality while reducing noise, thereby resolving the contradiction between noise reduction and speech intelligibility.
Solution Approach 2:
The patent introduces dynamic adjustment of noise reduction strength based on real-time SNR measurements. The system transitions from static gain reduction to dynamic gain reduction where the maximum gain reduction varies with environmental conditions, allowing optimal noise reduction without compromising speech intelligibility in different acoustic scenarios.
2Object-affected harmful factors
If maximum gain reduction is increased to reduce noise, then noise reduction is improved, but speech distortion increases leading to decreased intelligibility
Solution Approach 1:
The patent modifies the maximum gain reduction parameter based on SNR conditions. In low SNR environments where noise is more prominent, higher gain reduction is permitted. In high SNR environments where speech quality is more critical, lower gain reduction is applied. This dynamic parameter adjustment resolves the contradiction by adapting the noise reduction strength to environmental conditions.
Solution Approach 2:
The patent applies different levels of noise reduction strength in different SNR conditions. Instead of uniform noise reduction across all environments, the system applies localized optimization by adjusting maximum gain reduction according to the specific SNR condition, thereby reducing noise where necessary while preserving speech quality where important.
Data Source
AI summary
Disclosed herein, among other things, are methods and apparatus for improved noise reduction for hearing assistance devices. In various embodiments, a hearing assistance device includes a microphone and a processor configured to receive signals from the microphone. The processor is configured to perform noise reduction which adjusts maximum gain reduction as a function of signal-to-noise ratio (SNR), and which reduces the strength of its maximum gain reduction for intermediate signal-to-noise ratio levels to reduce speech distortion. In various embodiments, the hearing assistance device includes a memory configured to log noise reduction data for user environments. Also provided are methods to further adjust the noise reduction based on the logged information.