Binaural Hearing System Directional Pre-Processing
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Solution Overview
Problem
Existing binaural hearing systems face inaccuracies in global direction-dependent signal processing due to local pre-processing, which can introduce spatial distortions and affect the performance of overall directional noise reduction and source localization.
Innovation Solution
A method for operating a hearing system that involves generating pre-processed signals using adaptive beamforming with specific coefficients for each hearing device, ensuring minimal spatial distortion by defining a frontal direction and applying direction-sensitive pre-processing to attenuate sound signals within a restricted angular range, and using head-related and position-related transfer functions for accurate signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If local pre-processing is applied to microphone signals in each hearing device, then noise reduction and signal enhancement are improved, but spatial accuracy and distortion of global direction-dependent signal processing deteriorate
Solution Approach 1:
The patent divides the binaural hearing system into two independent processing paths: local pre-processing in each hearing device and global direction-dependent signal processing. Each hearing device processes its own microphone signals independently through local pre-processing, while the globally processed signals are generated separately and combined later, preventing interference between local and global processing stages
Solution Approach 2:
The patent extracts the global direction-dependent signal processing from the local pre-processing chain. By generating globally processed signals separately and combining them with locally pre-processed signals, the system removes the distortion that would otherwise be introduced by integrating global processing into the local processing path
2Adaptability or versatility
If head-related transfer functions are used for direction-dependent pre-processing, then directional signal processing capability is improved, but inaccuracy in global directional processing increases
Solution Approach 1:
The patent segments the transfer function application into two distinct stages: local head-related transfer functions applied during local pre-processing in each hearing device, and global transfer functions applied separately during global direction-dependent signal processing. This separation ensures that each processing stage uses the appropriate transfer function without interfering with the other
Solution Approach 2:
The patent introduces an intermediary processing stage that combines locally pre-processed signals with globally processed signals. This intermediary stage allows both local and global directional processing to coexist without direct interference, maintaining the integrity of both processing paths
Data Source
AI summary
A hearing system includes first and second hearing devices. A first reference signal and a first auxiliary signal are generated for the first hearing device from an ambient sound by a first reference microphone and a first auxiliary microphone, respectively. A first pre-processed signal is generated by direction-sensitive pre-processing the reference and auxiliary signals. The first pre-processed signal shows a maximal attenuation for a generic sound signal originating from an angular range of [+90°, +270°] with respect to a first frontal direction, and a first head-related transfer function for the first hearing device is provided. A second pre-processed signal is generated for the second hearing device by its microphones which is representative of the ambient sound, and a second position-related transfer function is provided for the second hearing device. The pre-processed signals are subjected to a direction-sensitive signal processing task using the first and second head-related transfer functions.