Hearing Aid Feedback Compensation Without Beamformer Interference
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Solution Overview
Problem
Existing hearing aids with multiple input transducers face challenges in combining directional processing with effective feedback compensation without interfering with the directional controller's function or increasing system complexity.
Innovation Solution
A processor for hearing aids that applies feedback compensation after initial directional processing and low-frequency boosting, estimating the feedback path to include only the output transducer, acoustic path, microphones, and low-frequency boosters, but not the beamformer, to avoid interference and simplify the feedback estimation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback compensation is applied before directional processing, then feedback suppression is improved, but directional controller function is interfered with and system complexity increases
Solution Approach 1:
The patent segments the feedback compensation process into two distinct stages: first applying feedback compensation to individual microphone signals, then applying directional processing to the compensated signals. This segmentation allows each processing stage to operate independently without interfering with the other, resolving the contradiction between feedback suppression effectiveness and system complexity.
Solution Approach 2:
The patent applies feedback compensation as a preliminary action before directional processing. By pre-compensating the microphone signals for feedback, the subsequent directional processing can focus solely on spatial filtering without being burdened by feedback artifacts, thereby improving overall system performance while maintaining manageable complexity.
2Measurement precision
If feedback path estimation includes beamformer, then compensation accuracy is improved, but processor load and system complexity increase
Solution Approach 1:
The patent extracts the beamformer from the feedback path estimation process. By determining that the beamformer does not significantly contribute to the feedback path and removing it from the estimation model, the system achieves adequate compensation accuracy with reduced processor load and simplified implementation.
Solution Approach 2:
The patent applies partial action by including only the essential components (microphones, acoustic path, output transducer, low-frequency boosters) in the feedback path estimation, omitting the beamformer. This partial inclusion provides sufficient compensation accuracy without the excessive computational burden of modeling the complete signal path.
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 allows for improved feedback compensation in hearing aids without adversely affecting directional processing, reducing system complexity and processor load, and achieving desired directional properties by controlling the combination of feedback-compensated signals.
Implementation Method 1
a first microphone for converting sound into a first audio signal
Implementation Method 2
a second microphone for converting sound into a second audio signal
Implementation Method 3
an output transducer for converting the hearing loss compensation signal into an acoustic output
Data Source
AI summary
A hearing aid comprises two microphones, directional processing means for combining the respective audio signals to form a spatial signal, a beamformer for controlling the directional processing means to provide adaptation of the spatial signal, and means for boosting low frequencies of the spatial signal. A feedback estimator generates a feedback compensation signal, which is combined with the boosted spatial signal. By applying feedback compensation only after directional processing and low frequency boosting, the device avoids interference by the feedback estimator with the function of the beamformer. The invention also provides a method of processing signals in a hearing aid.