Hearing Aid Whistling Detection Using Average Frequency Stability
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Solution Overview
Problem
Existing hearing aid technologies face challenges in effectively detecting and suppressing whistling, which limits maximum gain and can be annoying and harmful to users, due to inefficient methods that require significant processing power and may cause signal distortions.
Innovation Solution
A method that determines the stability of the average frequency of an input signal by comparing differences in consecutive blocks, using a simple threshold-based approach to identify potential whistling, and employs a feedback cancellation filter to suppress it, while also adjusting gain to prevent whistling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variance criterion is used to detect whistling, then whistling detection can be achieved, but processing power requirements increase significantly
Solution Approach 1:
The patent changes the detection parameter from variance (second power calculation) to zero-crossing rate, which is a simpler arithmetic operation that requires much less processing power while maintaining effective whistling detection capability
Solution Approach 2:
The patent replaces complex arithmetical operations (variance calculation involving squaring) with simpler signal processing operations (zero-crossing detection), reducing computational complexity and processing power requirements
2Object-generated harmful factors
If a notch filter is used to suppress whistling, then whistling can be reduced, but signal distortions and audible changes occur
Solution Approach 1:
The patent extracts only the essential characteristic of whistling (zero-crossing rate) for detection, avoiding the need for complex frequency filtering that causes distortions. The solution focuses on detecting and responding to the harmful characteristic without attempting to filter the entire signal spectrum
Solution Approach 2:
The patent employs dynamic gain adjustment that adapts to the detected whistling conditions, allowing the system to respond flexibly to changing acoustic environments without imposing fixed frequency characteristics that would cause signal distortions
3Reliability
If gain is increased to compensate for hearing loss, then hearing aid effectiveness improves, but whistling becomes more likely to occur
Solution Approach 1:
The patent performs preliminary detection of whistling conditions using zero-crossing rate analysis before whistling fully develops, allowing the system to take preventive action by reducing gain before the harmful feedback loop establishes itself
Solution Approach 2:
The patent implements a feedback mechanism where the zero-crossing rate detection continuously monitors the audio signal and adjusts the gain accordingly, creating a closed-loop system that adapts to prevent whistling while maintaining hearing compensation effectiveness
Data Source
AI summary
A method for detecting whistling in an audio system includes determining an average frequency of an input signal of the audio system, sampling the input signal in consecutive blocks of at least one sample, wherein the average frequency is determined blockwise, and determining whether feedback related whistling is present in the input signal of the audio system by evaluating a stability of the average frequency, wherein the evaluation of the stability of the average frequency comprises: determining a difference of two values of the determined average frequency for two blocks, and comparing the determined difference to a first threshold value.