Hearing Aid Noise Cancellation Using Deconvolution Filters
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Solution Overview
Problem
Traditional hearing aid systems face challenges in effectively suppressing noise due to the interference between direct and amplified sound signals, which affects sound quality and noise cancellation.
Innovation Solution
The method involves obtaining a combined transfer function of hearing aid components, decomposing it into minimum phase and all-pass transfer functions, and using a deconvolution filter to process sounds in both main and active noise cancelling signal paths, combining them to reduce noise and alleviate hearing deficits with low delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hearing aid systems use frequency-dependent amplification to compensate for hearing loss, then hearing deficit is alleviated, but noise suppression is ineffective due to interference between direct and amplified sound signals
Solution Approach 1:
The patent divides the signal processing into separate frequency bands using a filter bank, allowing independent processing of each band. This segmentation enables the system to apply different gain values to different frequency bands, effectively compensating for frequency-dependent hearing loss while maintaining noise suppression capability by processing each band independently rather than as a mixed signal.
Solution Approach 2:
The patent dynamically adjusts the gain values for different frequency bands based on the detected noise level and hearing loss characteristics. By changing the gain parameters adaptively, the system can suppress noise in specific frequency bands while preserving audible speech frequencies, resolving the contradiction between noise suppression and maintaining hearing compensation effectiveness.
2Reliability
If hearing aid systems process sound signals through multiple frequency bands independently, then hearing loss compensation is improved, but system complexity increases
Solution Approach 1:
The patent implements a filter bank that serves multiple functions: it divides the audio signal into frequency bands for hearing loss compensation, simultaneously provides noise suppression capability, and enables adaptive gain control. This multi-functionality reduces the need for separate processing stages, thereby managing system complexity while improving hearing loss compensation reliability.
3Reliability
If active noise cancelling is implemented in hearing aid systems, then noise cancellation is improved, but delay in signal processing increases
Solution Approach 1:
The patent performs preliminary signal processing by dividing the audio signal into frequency bands before the main noise cancellation processing. This preliminary segmentation allows the system to prepare the signal structure in advance, reducing the computational delay during active noise cancellation operations while maintaining effective noise cancellation performance.
Data Source
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AI summary
A hearing aid system (500) with active noise cancelling and a method for operating such a hearing aid system.