Personalized Pinna Cue Filtering for BTE Hearing Devices
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Solution Overview
Problem
Hearing impaired individuals using behind-the-ear (BTE) hearing devices do not receive natural pinna shaping cues, leading to degraded sound localization and externalization due to generic pinna restoration patterns that do not account for individual variations.
Innovation Solution
A method and system that utilize both in-the-ear (ITE) and behind-the-ear (BTE) acoustic input transducers to capture configuration sound signals, determine personalized filter values, and compensate for reduced spectral pinna cues, thereby personalizing sound processing to enhance localization and externalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If generic pinna restoration patterns are used to shape sound signals from BTE microphones, then sound processing can be implemented, but localization and externalization performance is degraded due to not matching individual pinna characteristics
Solution Approach 1:
The system performs preliminary measurements by playing test signals through the hearing device and recording the acoustic response with microphones positioned in the ear canal. This preliminary action captures the individual pinna characteristics before normal operation, allowing the creation of personalized transfer functions that are stored and applied during subsequent use, thus resolving the contradiction between generic processing and individual matching.
Solution Approach 2:
The system uses feedback by comparing the sound signals captured by BTE microphones with the natural pinna-shaped signals captured by in-ear microphones. The measured transfer function represents the difference between these two paths, and this feedback information is used to generate compensating filters that are applied to the BTE microphone signals, thereby achieving individualized pinna restoration and improving localization performance.
2Measurement precision
If in-the-ear microphone is used to capture naturally shaped sound, then spectral pinna cues are preserved, but feedback issues and gain requirements limit its usability
Solution Approach 1:
The system introduces an intermediary solution by using the in-ear microphone only during a brief calibration phase to measure the individual pinna characteristics, rather than relying on it continuously. The measured transfer function serves as an intermediary representation of the pinna's effect, which is then applied through digital filtering to the BTE microphone signals, allowing spectral pinna cues to be restored without the reliability issues of continuous in-ear microphone use.
Solution Approach 2:
The system creates a copy of the natural pinna shaping effect by measuring the transfer function during calibration and applying this copied characteristic through digital filters during normal operation. This allows the benefits of naturally shaped sound to be replicated without requiring the in-ear microphone to be continuously active, thus resolving the contradiction between preserving spectral cues and maintaining reliability.
3Reliability
If BTE microphones are used to receive sound, then feedback issues are reduced, but spectral pinna cues are lost due to placement outside the ear
Solution Approach 1:
The system replaces the mechanical solution of placing microphones inside the ear (which provides natural pinna shaping but causes feedback) with a digital solution. BTE microphones are used to capture sound, and then digital filtering based on measured individual transfer functions is applied to synthetically restore the spectral pinna cues that would otherwise be lost, thus achieving both reliability and measurement precision.
Solution Approach 2:
The system changes the parameters of the sound signal by applying frequency-dependent filtering based on the measured transfer function. This parameter change restores the spectral characteristics that are normally imposed by the pinna, transforming the BTE microphone output to match the spectral profile of in-ear captured sound, thereby compensating for the loss of spectral pinna cues while maintaining the reliability benefits of BTE placement.
Data Source
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AI summary
Disclosed is a method (200) at a system (100) comprising a hearing device (10) comprising a first acoustic input transducer (1) and one or more second acoustic input transducers (2, 3). The method (200) comprises the steps of receiving (210) by the first and the one or more second acoustic input transducers (2, 3) a configuration sound signal (20) originating from a direction (D), providing (220) from the first acoustic input transducer (1) an in-the-ear received signal (22) and from the one or more second acoustic input transducers (2, 3) a behind-the-ear received signal (24, 25, 24', 25'), determining (240) filter values of a hearing device personalized configuration filter (6) and compensating (250), by the hearing device (10), for reduced spectral pinna cues of sound signals received by the one or more second acoustic input transducers (2, 3), thereby personalizing a sound processing of the hearing device (10).