Bone Conduction Biometric Identification via Transfer Functions

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Solution Overview

Problem

Biometric identification systems often require specific user actions, such as positioning a camera or placing a finger, which can be inconvenient and may not be perfectly reliable, necessitating the use of multiple authentication methods for improved accuracy.

Innovation Solution

A method utilizing bone conduction headphones that determines transfer functions for audio signals through a person's head by comparing signals from outward-facing and inward-facing transducers, allowing for biometric identification without explicit user actions, using adaptive filters and quality criteria to ensure accurate verification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional biometric systems (facial recognition, fingerprint recognition) are used, then biometric identification can be performed, but specific user actions are required which reduces ease of operation and may lower reliability

Engineering Contradiction:

Improveease of operationVSAvoidreliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs biometric identification automatically without requiring explicit user actions. The bone conduction earpiece passively captures sound waves transmitted through the user's skull during normal speech, and the system automatically processes these signals to verify identity, making the user experience seamless and convenient while maintaining reliable authentication

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces traditional mechanical biometric systems (fingerprint scanners, facial recognition cameras) with an acoustic bone conduction system. Instead of requiring physical contact or specific positioning, the system uses sound waves transmitted through bone to capture unique acoustic signatures for identification

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If multiple forms of independent biometric authentication are used, then reliability is improved, but device complexity increases

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bone conduction earpiece serves multiple functions: it acts as both an audio output device and a biometric sensing device. The same hardware components (transducers, microphones, processors) are used for both delivering audio and capturing acoustic signals for identification, eliminating the need for separate authentication devices and reducing overall system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If bone conduction earpiece is used for biometric identification, then ease of operation is improved by eliminating specific user actions, but measurement precision must be ensured through quality criteria

Engineering Contradiction:

Improveease of operationVSAvoidmeasurement precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system continuously monitors the quality of acoustic signals captured during bone conduction and provides feedback to adjust processing parameters. Quality criteria are applied in real-time to verify signal validity, and the system adapts its measurement thresholds to maintain precise identification while requiring no user intervention

Inventive Principle:

Principle #23Feedback

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

This approach provides a non-invasive and non-obtrusive method for verifying identity by leveraging the unique sound conduction path through a person's head, enhancing reliability and convenience by using the inherent characteristics of bone conduction for biometric authentication.

Implementation Method 1

generating a first transducer output signal from the first transducer

Methodology Applied

Scientific EffectSound wave detection: Sound

Implementation Method 2

The first transducer may comprise a microphone

Methodology Applied

Scientific EffectMicrophone transduction:

Implementation Method 3

determining at least one transfer function for bone conduction of an audio signal through the person's head

Methodology Applied

Scientific EffectBone conduction:

Implementation Method 4

generating a second transducer output signal from the second transducer

Methodology Applied

Scientific EffectSound wave detection: Sound

Implementation Method 5

The second transducer may comprise a microphone or an accelerometer

Methodology Applied

Scientific EffectAccelerometer detection: Accelerometer

Implementation Method 6

determining a transfer function based on a relationship between the first transducer output signal and the second transducer output signal

Methodology Applied

Scientific EffectSignal processing:

Implementation Method 7

determining the or each transfer function by means of an adaptive filter adapted using a Least Mean Squares method

Methodology Applied

Scientific EffectLeast Mean Squares method:

Data Source

PatentUS11900730B2Biometric identification

Publication Date: 2024.02.13 CIRRUS LOGIC INC

AI summary

A method of biometric identification of a person comprises, during an enrolment phase determining at least one enrolment transfer function for bone conduction of an audio signal through an enrolling user's head. The enrolment transfer function is stored. During a verification phase, at least one verification transfer function for bone conduction of an audio signal through the person's head is determined. It is then determined from the at least one verification transfer function and the at least one enrolment transfer function whether the person is the enrolling user.