Auditory Prosthesis Gain Control for SNR Preservation
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Solution Overview
Problem
Conventional auditory prostheses, such as cochlear implants, experience a reduction in signal-to-noise ratio (SNR) due to the compression process following noise reduction, which counteracts the benefits of noise reduction algorithms in noisy environments, leading to poor speech intelligibility in social situations.
Innovation Solution
Implementing a gain control stage prior to the compression stage in the audio processing pathway to minimize signal compression, thereby retaining the SNR benefits achieved by noise reduction algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compression is applied to the audio signal after noise reduction, then the dynamic range is reduced and the signal fits within the device's processing range, but the signal-to-noise ratio deteriorates because the compressed signal reduces the relative difference between speech peaks and noise peaks
Solution Approach 1:
The patent applies gain control before compression to pre-adjust the signal level and minimize the need for aggressive compression. By controlling the signal level in advance, the system retains more of the original signal-to-noise ratio while still preventing overload and maintaining processing stability.
Solution Approach 2:
The patent separates the dynamic range control function into two distinct stages: gain control stage and compression stage. This segmentation allows each stage to perform its specific function optimally - gain control for level management and compression for dynamic range reduction - without interfering with the signal-to-noise ratio.
2Measurement precision
If noise reduction algorithms are used in auditory prostheses, then performance in selective environmental noises improves, but performance in mildly to very noisy environments with multiple speakers remains poor
Solution Approach 1:
The gain control stage operates before compression to preserve the signal-to-noise ratio improvements achieved by noise reduction algorithms. By minimizing subsequent compression, the system maintains the benefits of noise reduction across various listening conditions including complex environments with multiple speakers.
Solution Approach 2:
The patent dynamically adjusts the gain control parameters to optimize performance across different listening environments. By changing the gain parameters adaptively, the system maintains better speech intelligibility whether the environment has selective noise or complex multi-speaker scenarios.
Data Source
AI summary
A method of processing audio signals for an auditory prosthesis is provided. The method includes a noise reduction step and a later compression step. A gain control step is provided prior to the compression step. The gain control step operates so as to minimize the occurrence of signal compression in the compression step. An auditory prosthesis arranged to provide the method is also provided.