Adaptive Feedback Cancellation in Hearing Aids
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Solution Overview
Problem
Hearing assistance devices face feedback issues due to the amplification of audible signals, which can be exacerbated by increased volume or proximity to acoustically reflecting surfaces, and existing solutions fail to effectively address these challenges in varying acoustic environments and device configurations.
Innovation Solution
The implementation of adaptive feedback cancellation parameters that are continuously updated by comparing signal characteristics between non-acoustic audio signals and feedback portions, allowing for improved detection and characterization of feedback, even when the microphone amplification path is inactive, using additional environmental information such as geometry and vent characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hearing assistance device volume is increased, then the audible signal amplification is improved, but feedback is more likely to occur
Solution Approach 1:
The patent implements a feedback cancellation system that continuously monitors the feedback signal and uses adaptive filters to generate an anti-feedback signal. This anti-feedback signal is combined with the original signal to cancel out the harmful feedback, allowing high volume operation without feedback interference.
Solution Approach 2:
The system converts the harmful feedback signal into a useful resource by using it to train adaptive filters. The feedback signal, which would normally be unwanted, is instead utilized to characterize the acoustic path and generate cancellation signals that actively suppress feedback, turning the harmful effect into the mechanism for its own elimination.
2Ease of operation
If the hearing assistance device is moved closer to an acoustically reflecting surface, then the device can be positioned for optimal hearing assistance, but feedback is more likely to occur
Solution Approach 1:
The system continuously monitors acoustic feedback and uses adaptive filtering to cancel the feedback signal. This allows the device to be positioned close to acoustically reflecting surfaces for optimal hearing assistance while the feedback cancellation system actively suppresses any feedback that occurs.
Solution Approach 2:
The feedback cancellation parameters are continuously adapted in real-time based on the acoustic environment and device positioning. This dynamic adaptation allows the system to maintain optimal performance regardless of changes in device position or acoustic conditions, resolving the contradiction between positioning and feedback.
3Object-generated harmful factors
If existing feedback cancellation solutions are used, then feedback reduction is achieved, but the solutions fail to effectively address feedback in varying acoustic environments and device configurations
Solution Approach 1:
The system employs continuously adapting feedback cancellation parameters that update in real-time based on the acoustic environment and device configuration. This dynamic adaptation enables the same system to effectively handle varying acoustic environments and device configurations without requiring manual reconfiguration.
Solution Approach 2:
The system performs preliminary characterization of the acoustic path using non-acoustic audio signals before feedback occurs. This preliminary action allows the adaptive filters to be pre-configured with appropriate parameters, enabling effective feedback cancellation to start immediately when acoustic feedback occurs, regardless of the specific acoustic environment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces feedback in hearing assistance devices by continually updating adaptive feedback cancellation parameters, improving performance across different acoustic environments and usage configurations, thereby enhancing user experience.
Implementation Method 1
transduce the audio stream signal into an audible audio output at a speaker at the hearing assistance device
Implementation Method 2
transduce an audible input into an input audible signal at a microphone at the hearing assistance device
Data Source
AI summary
To provide improved feedback reduction in hearing assistance devices, technical solutions described herein include remeasuring a feedback path and updating adaptive feedback cancellation parameters whenever a user receives and plays an audio stream signal. When the user converts the audio stream signal into an acoustic audio signal using a speaker within the hearing assistance device, a feedback portion of the acoustic audio signal may be fed back into the microphone of the hearing assistance device. The hearing assistance device can then compare the feedback portion to the received audio stream signal, and that comparison can be used to update adaptive feedback cancellation parameters within the hearing assistance device. When the hearing assistance device receives an acoustic audio input at the microphone, it may amplify that input and apply the received acoustic audio input based on the updated adaptive feedback cancellation parameters to reduce or minimize feedback.