Adaptive Occlusion Cancellation Filter for Ear-Wearable Audio Transparency

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Solution Overview

Problem

Existing ear-wearable devices struggle to accurately reproduce the perception of ambient sound and own-voice for an occluded ear canal, leading to inaccurate audio transparency due to separate implementations of active occlusion cancellation (AOC) and hear-through processing.

Innovation Solution

The implementation of an adaptive occlusion cancellation filter in an ear-wearable device, which estimates a leakage path between an external source and the eardrum, is used to update an adaptive hear-through filter, jointly optimizing both AOC and hear-through processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If separate implementations of active occlusion cancellation and hear-through processing are used, then device complexity is reduced, but audio transparency accuracy deteriorates

Engineering Contradiction:

Improveimplementation complexityVSAvoidaudio transparency accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent combines separate AOC and hear-through processing into a unified joint optimization framework. The adaptive filters for both functions share common leakage path estimates and are optimized simultaneously, improving audio transparency accuracy while managing system complexity through integrated design.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The leakage path estimation mechanism serves dual purposes: it supports both active occlusion cancellation and hear-through processing. By using a universal estimation approach for the leakage path, the system achieves accurate audio transparency for both functions without requiring separate independent implementations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If adaptive filters are updated frequently to improve audio transparency, then computational load increases, but processing accuracy improves

Engineering Contradiction:

Improveaudio transparency accuracyVSAvoidcomputational energy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The adaptive filters are updated periodically rather than continuously. The system uses incremental updates at specific intervals or triggering events, reducing computational energy consumption while maintaining accurate audio transparency. This periodic update approach balances processing accuracy with energy efficiency.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The adaptive filter system automatically adjusts its own parameters based on real-time feedback from the acoustic environment. The leakage path estimates and filter coefficients are self-updated using incoming audio signals, reducing the need for external computational intervention and optimizing energy usage.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12238473B2Apparatus and method for performing active occlusion cancellation with audio hear-through

Publication Date: 2025.02.25 STARKEY LABORATORIES INC

AI summary

Adaptive occlusion cancellation is performed in an ear-wearable device using an adaptive filter. An adaptive gain of the adaptive filter is used to determine a leakage path estimate between an external source and an eardrum of the user through the ear-wearable device. The leakage path estimate is used to update an adaptive hear-through filter of the ear-wearable device. The updated adaptive hear-through filter is used for hear-through processing in the ear-wearable device.