Hearing Aid Directional System Using Blocking Matrix and Adaptive Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hearing aid systems face challenges in accurately classifying sound environments and directing audio signals, particularly in distinguishing between target sounds and noise, which affects the performance of features like beamforming and noise reduction.
Innovation Solution
The method involves transforming input signals into the time-frequency domain using a filter bank, followed by a directional system that uses a blocking matrix and adaptive filtering to separate target signals from noise, while estimating the Inter-Microphone Transfer Function (IMTF) to improve beamforming performance and robustness, and employing a phase versus frequency plot for sound classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a directional system with blocking matrix and adaptive filtering is used to separate target signals from noise, then speech intelligibility and noise reduction are improved, but device complexity increases
Solution Approach 1:
The patent divides the sound processing task into distinct stages: filter bank transformation, blocking matrix operation, adaptive filtering, and sound classification. Each stage handles a specific aspect of separating target signals from noise, making the complex system more manageable and implementable through modular processing blocks
Solution Approach 2:
The blocking matrix serves as an intermediary component that transforms the input signals into a form where target and noise components are separated into different output channels. This intermediate transformation enables subsequent adaptive filtering to more effectively enhance target signals while suppressing noise
2Measurement precision
If beamforming is used to enhance target signal directionality, then speech intelligibility improves, but robustness to noise and variations in acoustic environment deteriorates
Solution Approach 1:
The patent employs adaptive filtering with time-varying coefficients that dynamically adjust to changing acoustic environments. The filter coefficients are continuously updated based on incoming signals, allowing the system to maintain optimal beamforming performance while adapting to noise variations and environmental changes, thus improving robustness
Solution Approach 2:
The system changes key parameters including filter coefficients, time-frequency bin selections, and processing gains based on detected sound environment characteristics. By dynamically adjusting these parameters, the system optimizes beamforming performance for different acoustic conditions while maintaining robustness to noise and environmental variations
3Reliability
If frequency-dependent amplification is used to compensate for hearing loss, then hearing aid performance improves, but device complexity increases
Solution Approach 1:
The patent divides the audible frequency range into multiple frequency bands using a filter bank. Each frequency band is independently processed with appropriate gain adjustments based on the user's hearing loss profile. This segmentation allows frequency-dependent amplification to be implemented in a modular manner, improving hearing compensation while keeping individual processing blocks relatively simple
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of operating a hearing aid system in order to provide improved performance of a directional system (100) and a hearing aid system for carrying out the method.