Biometric Recognition Using Inertial Sensor Tremor Analysis

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Solution Overview

Problem

Biometric recognition systems face challenges in balancing security and user acceptability, particularly in real-life scenarios, as they often require intrusive methods or complex equipment, and existing tremor-based systems struggle to distinguish between physiological and pathological tremors effectively.

Innovation Solution

A biometric recognition system utilizing inertial sensors, such as accelerometers and gyroscopes, to detect and classify involuntary hand tremor, providing a fast, less intrusive authentication method by analyzing tremor patterns and features extracted through Weighted Frequency Fourier Linear Combiner (WFLC) filtering and spectral density estimation, allowing for secure device unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional biometric recognition methods (e.g., facial recognition, fingerprint scanning) are used to ensure security, then security is improved, but user acceptability deteriorates due to intrusive procedures and complex equipment requirements

Engineering Contradiction:
ImprovesecurityVSAvoiduser acceptability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system uses the user's own involuntary physiological tremor as the biometric identifier, eliminating the need for active user participation. The tremor occurs naturally without user control, making authentication automatic and non-intrusive while maintaining security through unique physiological patterns

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical or optical biometric systems with an inertial sensor-based detection system. Instead of using cameras, fingerprints, or iris scanners, the system uses simple accelerometers to detect tremor patterns, significantly reducing equipment complexity while maintaining authentication capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Extent of automation

If existing tremor-based biometric systems are used, then authentication capability is provided, but the system fails to effectively distinguish between physiological and pathological tremors, reducing reliability

Engineering Contradiction:
Improveauthentication capabilityVSAvoidtremor classification accuracy
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The system changes the parameters used for tremor analysis by focusing on specific frequency ranges (4-12 Hz for physiological tremor) and using multiple inertial measurement parameters (acceleration, velocity, displacement) to differentiate between physiological and pathological tremors based on their distinct spectral characteristics

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system incorporates a feedback mechanism where the classifier continuously analyzes tremor patterns and adjusts authentication decisions based on the distinction between physiological and pathological tremor characteristics, improving reliability through iterative pattern recognition

Inventive Principle:
Principle #23Feedback

3Reliability

If complex biometric recognition equipment is deployed to improve security, then security is improved, but device complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidequipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or optical biometric systems with an inertial sensor-based detection system. Instead of using cameras, fingerprints, or iris scanners, the system uses simple accelerometers to detect tremor patterns, significantly reducing equipment complexity while maintaining authentication capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The inertial sensors used in the system serve multiple functions: they detect tremor patterns for authentication, track device orientation, and monitor user interaction patterns. This multi-functionality reduces the need for dedicated biometric hardware, simplifying the overall device architecture

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables reliable and efficient biometric recognition with minimal user intervention, capable of authenticating a device owner within one second, offering a balance between security and acceptability by differentiating between authorized and unauthorized users based on tremor patterns, even in dynamic real-life conditions.

Implementation Method 1

a first inertial sensor, such as an accelerometer, to detect linear acceleration of the hand

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

a second inertial sensor, such as a gyroscope, to detect angular velocity of the hand

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

Filtering and feature extraction are performed using a Weighted Frequency Fourier Linear Combiner (WFLC)

Methodology Applied
Scientific EffectFourier analysis:

Data Source

PatentUS10628568B2Biometric recognition system
Publication Date: 2020.04.21 TOBII TECHNOLOGIES LTD
  • US10628568B2 patent drawing
  • US10628568B2 patent drawing
  • US10628568B2 patent drawing

AI summary

A biometric recognition system for a hand held computing device incorporating an inertial measurement unit (IMU) comprising a plurality of accelerometers and at least one gyroscope is disclosed. A tremor analysis component is arranged to: obtain from the IMU, accelerometer signals indicating device translational acceleration along each of X, Y and Z axes as well as a gyroscope signal indicating rotational velocity about the Y axis during a measurement window. Each of the IMU signals is filtered to provide filtered frequency components for the signals during the measurement window. The accelerometer signals are combined to provide a combined filtered accelerometer magnitude signal for the measurement window. A spectral density estimation is provided for each of the combined filtered accelerometer magnitude signal and the filtered gyroscope signal. An irregularity is determined for each spectral density estimation; and based on the determined irregularities, the tremor analysis component attempts to authenticate a user of the device.