Binaural Beamformer Weights for Quantization Noise

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Solution Overview

Problem

Binaural beamformers for hearing aids ignore quantization noise during signal transmission, leading to poor performance in practical applications due to limited transmission capacity and noise introduction from data compression.

Innovation Solution

A hearing device that accounts for quantization noise by using a noise covariance matrix incorporating both acoustic and quantization components, allowing for optimized beamformer filtering weights and improved noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If data compression is applied to transmit microphone signals through the wireless communication link, then the limited transmission capacity is satisfied, but quantization noise is introduced which degrades beamforming performance

Engineering Contradiction:
Improvetransmission capacityVSAvoidquantization noise
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the quantization noise covariance matrix corresponding to each quantization scheme before actual beamforming operation. When a quantization scheme is selected, the corresponding pre-computed noise covariance matrix is immediately available for beamformer control, avoiding real-time computation delays and enabling rapid adaptation to different transmission capacity conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the beamformer control adaptable to different quantization schemes dynamically. The control unit can switch between different quantization schemes and their corresponding noise covariance matrices based on current transmission conditions, battery status, and signal characteristics, allowing the system to optimize performance under varying operational constraints rather than being fixed to a single configuration.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If prior art binaural beamforming systems ignore quantization noise, then the system complexity is reduced, but the performance deteriorates in practical applications

Engineering Contradiction:
Improvesystem complexityVSAvoidbeamforming performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the quantization noise covariance matrix corresponding to each quantization scheme before actual beamforming operation. When a quantization scheme is selected, the corresponding pre-computed noise covariance matrix is immediately available for beamformer control, avoiding real-time computation delays and enabling rapid adaptation to different transmission capacity conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of quantization noise into a beneficial factor by explicitly modeling it through the noise covariance matrix. Instead of treating quantization noise as an unwanted disturbance to be ignored, the system uses it as known information to optimize beamformer weights, thereby improving speech enhancement performance in practical wireless binaural hearing aid applications.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the control unit adapts to specific quantization schemes with corresponding noise covariance matrices, then the noise reduction performance is improved, but the device complexity increases

Engineering Contradiction:
Improvenoise reduction performanceVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing the quantization noise covariance matrix corresponding to each quantization scheme before actual beamforming operation. When a quantization scheme is selected, the corresponding pre-computed noise covariance matrix is immediately available for beamformer control, avoiding real-time computation delays and enabling rapid adaptation to different transmission capacity conditions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by associating different quantization schemes with specific noise covariance matrix parameters. The control unit selects appropriate parameters (noise covariance matrices) based on the chosen quantization scheme, allowing the beamformer to adapt its behavior to match the actual noise characteristics introduced by different data compression levels, thereby optimizing noise reduction performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3306956B1A binaural beamformer filtering unit, a hearing system and a hearing device
Publication Date: 2019.08.14 OTICON
  • EP3306956B1 patent drawingFigure 1A
  • EP3306956B1 patent drawingFigure 1B
  • EP3306956B1 patent drawingFigure 1C~1D

AI summary

The application relates to a hearing device adapted for being located at or in a first ear of a user, or to be fully or partially implanted in the head at a first ear of a user, the hearing device comprising • a first input transducer for converting a first input sound signal from a sound field around the user at a first location, the first location being a location of the first input transducer, to a first electric input signal, the sound field comprising a mixture of a target sound from a target sound source and possible acoustic noise; • a transceiver unit configured to receive a first quantized electric input signal via a communication link, the first quantized electric input signal being representative of the sound field around the user at a second location, the first quantized electric input signal comprising quantization noise due to a specific quantization scheme; • a beamformer filtering unit adapted to receive said first electric input signal and said quantized electric input signal and to determine beamformer filtering weights, which, when applied to said first electric input signal and said quantized electric input signal, provide a beamformed signal, and • a control unit adapted to control the beamformer filtering unit, wherein the control unit is configured to control the beamformer filtering unit taking account of said quantization noise. The invention may e.g. be used for the hearing aids and other portable electronic devices with limited power capacity.