Hearing Prosthesis Spatial Pre-Filtering for Side-Sound Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Individuals with single-sided deafness face challenges in hearing conversation, localizing sound, and understanding speech in noisy environments due to the head-shadow effect, which prevents acoustic cues from reaching the brain and affects high-frequency sound reception.
Innovation Solution
A hearing prosthesis with a spatial pre-filter that uses a microphone array to generate primary and side reference signals, applying a side gain mask to enhance sensitivity to sounds from the side of the head, utilizing beamforming techniques and parametric gain masks to improve sound processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional microphones are used without spatial pre-filtering, then the device structure remains simple, but the sensitivity to sounds from the side of the head is poor due to the head-shadow effect
Solution Approach 1:
The audio signal processing is segmented into multiple directional components using a microphone array with different polar patterns. The first microphone generates a primary reference signal while the second microphone generates a side reference signal with nulls directed to the side, effectively segmenting the acoustic field into different spatial regions for targeted processing.
Solution Approach 2:
The spatial pre-filter applies preliminary processing to the received sound signals by generating directional reference signals before the main speech enhancement processing. The side gain mask is calculated in advance based on the primary and side reference signals, preparing the signal processing pipeline to handle side-coming sounds optimally before they enter the main processing stage.
2Reliability
If spatial pre-filtering with multiple microphones and beamforming is applied, then sound clarity and speech intelligibility improve, but the device complexity increases
Solution Approach 1:
The system applies local quality enhancement by directing processing resources specifically toward improving sensitivity to sounds from the side. The second microphone is configured with a polar pattern that has nulls directed to the side, creating a specialized processing path for side-coming sounds rather than treating all directions uniformly.
Solution Approach 2:
The side reference signal acts as an intermediary that captures spatial information about side-coming sounds and noise. This intermediary signal is used to calculate the side gain mask, which then modulates the primary reference signal to enhance speech intelligibility without requiring direct processing of all raw microphone signals.
3Object-affected harmful factors
If the second microphone polar pattern includes nulls directed to the side, then noise from the spatial region adjacent the first side is attenuated, but the coverage of the microphone array becomes asymmetric
Solution Approach 1:
The system deliberately introduces asymmetry by configuring the second microphone with a polar pattern that has nulls directed to the side. This asymmetric configuration is purposeful, designed to create a side gain mask that specifically targets and attenuates noise from the spatial region adjacent to the first side of the head, accepting reduced coverage in that direction as a trade-off for noise rejection.
Data Source
AI summary
Presented herein are techniques for increasing sensitivity of a hearing prosthesis to sound signals received from the “side” of a recipient. The sensitivity of the hearing prosthesis to sound signals received from the side of a recipient is provided by a spatial pre-filter that is configured to use a primary reference signal (i.e., a first directional signal) and a side reference signal (i.e., a second directional signal having at least one null directed to the side of the recipient) to calculate a side gain mask. The side gain mask includes gains for each of a plurality of frequency channels associated with the received sound signals.