Hearing Aid Deconvolution Filter Reduces Processing Delay

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Solution Overview

Problem

Traditional hearing aid systems face challenges in minimizing processing delay, which affects sound quality due to the use of filter banks with high frequency resolution, and existing solutions either introduce additional delays or do not adequately address the overall system's delay issues.

Innovation Solution

A hearing aid system incorporating a time-varying filter and a deconvolution filter, where the deconvolution filter's transfer function is the inverse of the combined transfer function of hearing aid components, reducing overall delay and improving signal processing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If filter banks with high frequency resolution are used, then noise reduction and hearing deficit alleviation are improved, but processing delay increases

Engineering Contradiction:
Improvefrequency resolutionVSAvoidprocessing delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts the minimum-phase components from the overall system transfer function and processes them separately through a deconvolution filter. By isolating these components, the system can compensate for their delay effects without requiring the entire signal to wait for full processing, thus reducing overall processing delay while maintaining high frequency resolution through the time-varying filter.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The deconvolution filter applies preliminary processing to cancel out the minimum-phase components before the main signal processing occurs. This preliminary action compensates for the delay introduced by minimum-phase components, allowing the time-varying filter to operate more efficiently without being constrained by the total processing time, thereby reducing overall delay while preserving frequency resolution.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If minimum-phase components are present in the system, then certain frequency responses are achieved, but additional delay is introduced

Engineering Contradiction:
Improvefrequency responseVSAvoidprocessing delay
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent applies inversion by creating a deconvolution filter with a transfer function that is the inverse of the minimum-phase components. This inverse filter cancels out the minimum-phase components' effect, effectively removing the delay they introduce while preserving their beneficial frequency response characteristics. The time-varying filter then operates on the deconvoluted signal without the constraint of minimum-phase delay.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3577909B1Method of operating a hearing aid system and a hearing aid system
Publication Date: 2022.11.16 WIDEX AS
  • EP3577909B1 patent drawingFigure 1
  • EP3577909B1 patent drawingFigure 2
  • EP3577909B1 patent drawingFigure 3

AI summary

A method (200) of operating a hearing aid system with a very low delay. The invention also provides a hearing aid system (100, 300, 400) adapted for carrying out such a method.