Hearing Aid Feedback Cancellation with ITE Microphone Spatial Cue Preservation
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Solution Overview
Problem
Hearing aid users experience poor sound source localization and increased cognitive loading due to internalized sound reproduction, leading to listening fatigue and potential removal of the device.
Innovation Solution
Incorporating an ITE microphone positioned in the outer ear, either at the entrance to the ear canal or inside it, to preserve spatial cues, combined with conventional BTE microphones, and using adaptive cue filters to minimize feedback and enhance sound localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microphones are positioned behind the ear (BTE configuration), then feedback is reduced, but spatial cues for sound localization are lost
Solution Approach 1:
The patent divides the microphone system into two separate components: BTE microphones positioned behind the ear for capturing sound with minimal feedback, and ITE microphones positioned in the ear canal for capturing spatial cues. This segmentation allows each microphone type to optimize its specific function without compromise.
Solution Approach 2:
The patent introduces an intermediary signal processing system that combines outputs from both BTE and ITE microphones. The ITE microphone signal serves as a mediator that provides spatial information to compensate for the loss of spatial cues in the BTE configuration, while the BTE microphone provides the primary audio signal with reduced feedback.
2Object-affected harmful factors
If hearing aids reproduce sound internally, then feedback is minimized, but sound source localization ability deteriorates
Solution Approach 1:
The patent applies local quality by positioning the ITE microphone specifically at the entrance to or inside the ear canal, where it can capture localized spatial cues from sounds arriving at the ear. This localized positioning preserves directional information that would otherwise be lost in the BTE configuration.
Solution Approach 2:
The patent adds a new dimension to the microphone system by incorporating the ITE microphone that captures spatial information from a different spatial location (inside the ear canal) compared to the BTE microphones (behind the ear). This dimensional addition provides complementary spatial cues for improved localization.
3Loss of information
If ITE microphones are positioned in the ear canal, then spatial cues are preserved, but feedback increases
Solution Approach 1:
The patent merges the outputs of BTE microphones and ITE microphones through signal processing. The BTE microphone signal, which has reduced feedback, is combined with the ITE microphone signal, which provides spatial cues. This merging allows the system to benefit from both configurations simultaneously.
Solution Approach 2:
The patent uses feedback principles by processing the ITE microphone signal to provide spatial information that compensates for the feedback-related localization problems. The system actively manages feedback by leveraging the complementary strengths of both microphone configurations.
Data Source
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AI summary
A hearing aid includes: a cue filter having an input that is provided with an output from the BTE sound input transducer; an adaptive feedback canceller configured to provide an output modelling a feedback path between the output transducer and the BTE sound input transducer, wherein the output modelling the feedback path is provided to a subtractor for subtraction of the output modelling the feedback path from the output of the BTE sound input transducer to obtain a difference, the subtractor outputting the difference to the cue filter; and a feedback and cue controller connected to the adaptive feedback canceller and the cue filter, wherein the feedback and cue controller is configured to control the cue filter to reduce a difference between an output of the ITE microphone and a combined output that is obtained using at least the cue filter.