Hearing Prosthesis SNR Loss Fitting Method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current digital hearing aids struggle to accurately compensate for signal-to-noise ratio (SNR) loss in hearing impaired individuals, leading to difficulties in understanding speech in noisy environments, as existing noise reduction algorithms introduce artifacts and are not practical for widespread use due to size and cost constraints.
Innovation Solution
A method for fitting hearing prostheses that involves estimating or measuring SNR loss data to determine parameter values for noise reduction algorithms, and using an environmental classifier to adjust noise reduction based on the user's current listening environment, combining beam forming and single observation noise reduction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single observation processing algorithms are used to improve signal-to-noise ratio, then objective SNR is improved, but artifacts are introduced into the desired signal leading to loss of speech cues
Solution Approach 1:
The patent combines multiple noise reduction algorithms (beam forming and spectral subtraction) into a unified processing system. The beam forming algorithm processes signals from multiple microphones to create spatial filtering, while spectral subtraction handles frequency-domain noise removal. This merging allows the system to achieve superior noise reduction performance compared to single algorithms, reducing artifacts while improving SNR through complementary processing mechanisms.
Solution Approach 2:
The system dynamically adjusts processing parameters based on environmental conditions and user characteristics. The beam forming algorithm modifies spatial filtering parameters according to the acoustic environment, while spectral subtraction adjusts frequency-domain parameters adaptively. This parameter adaptation allows optimal noise reduction performance across varying conditions while minimizing artifact generation through continuous optimization of processing characteristics.
2Measurement precision
If microphone array systems are used to improve SNR through spatial differences, then speech intelligibility is improved, but requirements for surface area on housing increase making them impractical for hearing aid applications
Solution Approach 1:
The patent implements a nested architecture where the beam forming algorithm processes signals from multiple microphones in a hierarchical manner. The system nests multiple processing stages within a compact structure, with the beam forming spatial filtering integrated alongside spectral subtraction processing. This nested arrangement enables sophisticated multi-stage noise reduction while maintaining a compact form factor suitable for hearing aid applications.
Solution Approach 2:
The system transitions from purely spatial approaches to a combination of spatial and frequency-domain approaches. By adding the frequency dimension through spectral subtraction, the system achieves enhanced noise reduction capability without requiring proportionally larger physical aperture. This dimensional expansion allows effective noise reduction through computational processing rather than solely through physical microphone array geometry.
3Reliability
If noise reduction algorithms are applied to compensate for SNR loss, then hearing ability in noisy environments is improved, but the complexity of the device increases
Solution Approach 1:
The noise reduction system is segmented into distinct functional modules: beam forming processing for spatial filtering and spectral subtraction for frequency-domain noise removal. Each module handles specific aspects of noise reduction independently, allowing for modular implementation and simplified maintenance. This segmentation reduces overall system complexity by dividing the complex noise reduction task into manageable, specialized processing stages that can be optimized separately.
Data Source
AI summary
An individual with a hearing loss often experiences at least two distinct problems: 1) the hearing loss itself i.e. an increase in hearing threshold level, and 2) a signal-to-noise ratio loss (SNR loss) i.e. a loss of ability to understand high level speech in noise as compared to normal hearing individuals. According to one aspect of the present invention, this problem is solved by selecting parameter values of a noise reduction algorithm or algorithms based on the individual user's SNR loss. Thereby, a degree of restoration/improvement of the SNR of noise-contaminated input signals of the hearing prosthesis has been made dependent on user specific loss data. According to another aspect of the present invention, a hearing prosthesis capable of controlling parameters of a noise reduction algorithms in dependence on the user's current listening environment as recognized and indicated by the environmental classifier has been provided.