Miniature Hearing Aid DOA Estimation Using Parametric Model
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Solution Overview
Problem
Current hearing aid beamforming technologies fail to effectively segregate sound sources under reverberant conditions, resulting in inadequate sound segregation for hearing-impaired individuals, with existing directional microphones having wide beams and insufficient segregation abilities.
Innovation Solution
A method and system for wideband direction of arrival (DOA) estimation using a parametric model based on space delays, implemented in a miniature device like a hearing aid, which provides a more selective beamforming capability by optimizing a Taylor expansion model to estimate the direction of sound sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional beamforming technology is used in hearing aids, then the device can provide directional sound enhancement, but the beam is too wide (30+ degrees) to achieve sufficient sound segregation and the hearing impaired cannot effectively separate multiple talkers
Solution Approach 1:
The patent divides the sound field into multiple directional beams using an array of microphones, where each beam corresponds to a specific direction of arrival. By segmenting the spatial audio field into discrete directional components, the system enables the hearing impaired to separately perceive and identify multiple talkers arriving from different directions, achieving effective sound segregation with narrower beams than traditional beamforming.
2Measurement precision
If narrower beams are used to improve sound segregation, then talker separation is enhanced, but side lobes from the back increase causing unwanted sounds to be amplified
Solution Approach 1:
The patent applies different processing characteristics to different spatial regions using an array of microphones. Each microphone captures sound from its local position, and the system processes these signals to create directional beams with controlled main lobes and suppressed side lobes. This local quality approach allows the system to maintain narrow beams for good talker separation while controlling side lobe levels to prevent amplification of unwanted sounds from behind.
3Measurement precision
If an array of microphones is used to achieve narrow beams and improved segregation, then sound source separation is enhanced, but the device complexity increases
Solution Approach 1:
The patent uses an array of microphones that serves multiple functions simultaneously: capturing sound from different directions, estimating direction of arrival, forming directional beams, and enabling talker separation. By making the microphone array multi-functional, the system achieves improved sound source separation and directional awareness without proportionally increasing device complexity, as the same hardware components perform multiple essential functions.
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
The solution enables improved sound segregation in noisy environments, allowing hearing-impaired individuals to better distinguish multiple talkers by activating narrow beams that attenuate unwanted sounds, enhancing speech intelligibility.
Implementation Method 1
providing an array of sound sensitive sensors, such as microphones, each sensor providing a stream of digital samples representing the sound field
Implementation Method 2
optimizing said model with respect to its parameters based on said sound samples... minimizing a cost function of the model with respect to said direction of arrivals
Data Source
AI summary
A hearing device comprises a sound system for estimating the direction of arrival of sound emitted by one or more sound sources creating a sound field. The sound system comprises an array of N sound receiving transducers (microphones), each providing an electric input signal, a processing unit comprising a) a model unit comprising a parametric model configured to be able to describe the sound field at the array as a function of the direction of arrival in a region surrounding and adjacent to the array; b) a model optimizing unit configured to optimize said model with respect to its parameters based on said sound samples; c) a cost optimizing unit configured to minimize a cost function of the model with respect to said direction of arrivals; d) an estimating unit configured to estimate the direction of arrival based on said parametric model with the optimized parameters and the optimized cost function.