Hearing System Sound Source Localization via Dynamic Model Switching
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Solution Overview
Problem
Existing hearing aid systems face challenges in accurately estimating the location of target sound sources, particularly in noisy environments, due to the presence of background noise and the filtering effects of the human head, which complicates the processing of acoustic signals received by microphones.
Innovation Solution
A hearing system that uses a beamformer unit and signal processing to estimate the direction of arrival of target sound signals, taking into account background noise and head-related transfer functions, and switches between sound propagation models based on environmental conditions and battery status, utilizing a maximum likelihood framework with simplified computational models for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sound propagation models are used to accurately estimate sound source location in noisy environments, then measurement precision is improved, but device complexity and computational requirements increase
Solution Approach 1:
The system dynamically adapts the complexity of sound propagation models based on environmental conditions and battery status. It switches between simplified models (e.g., free-field assumption) and more complex models (e.g., spherical head model with head-related transfer functions) to balance accuracy and computational load in real-time
Solution Approach 2:
The system changes key parameters of the sound propagation model based on operating conditions. It adjusts the level of detail in head-related transfer functions and noise covariance modeling according to environmental noise levels and battery charge, optimizing the trade-off between measurement precision and device complexity
2Measurement precision
If complex sound propagation models are used to accurately estimate sound source location, then measurement precision is improved, but memory requirements increase
Solution Approach 1:
The system dynamically adjusts memory allocation for sound propagation models based on operational needs. It loads only the necessary model complexity level into memory depending on environmental conditions and processing requirements, reducing overall memory complexity while maintaining precision when needed
3Measurement precision
If the system accounts for head-related transfer functions and background noise in localization, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The system changes operational parameters including model complexity and processing intensity based on battery status and environmental conditions. It reduces the use of head-related transfer functions and noise covariance calculations when battery charge is low or environmental noise is minimal, thereby reducing energy consumption while maintaining acceptable precision
Solution Approach 2:
The system periodically updates localization estimates rather than continuously processing at full complexity. It adjusts the update frequency and computational intensity based on environmental stability and battery charge levels, optimizing the balance between measurement precision and energy consumption over time
Data Source
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AI summary
The present disclosure deals with the problem of estimating the direction to one or more sound sources of interest relative to a user wearing a pair of hearing devices, e.g. hearing aids. A target signal is generated by a target signal source and transmitted through an acoustic channel to a microphone of a hearing system. Due to (potential) additive environmental noise, a noisy acoustic signal is received at the microphones of the hearing system. An essentially noise-free version of the target signal is transmitted to the hearing devices of the hearing system via a wireless connection. Each of the hearing devices comprises a signal processing unit comprising a (configurable) sound propagation model of the acoustic propagation channel from the target sound source to the hearing device when worn by the user. The sound propagation model is configured to be used for estimating a direction-of-arrival (DoA) of the target sound signal relative to the user.