Toothbrush Motion Analysis for Automatic User Identification

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Solution Overview

Problem

Existing toothbrush motion tracking systems face challenges in accurately identifying individual users, especially in shared environments, where manual login methods are inconvenient and prone to errors, necessitating an efficient and user-friendly method to attribute toothbrushing data correctly.

Innovation Solution

The system employs principal component analysis (PCA) on motion data from accelerometers to project toothbrush motion onto principal axes, extracting user-specific features that discriminate between users, allowing for automatic identification within a short brushing session, eliminating the need for manual login and reducing errors in data attribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual login methods are used for user identification, then system complexity is reduced, but user convenience deteriorates and error rates increase

Engineering Contradiction:
Improveuser convenienceVSAvoidsystem complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system automatically identifies users by analyzing their toothbrushing motion patterns without requiring manual login. The accelerometer captures motion data, PCA extracts features, and the system compares these against stored profiles to autonomously determine user identity, eliminating the need for manual authentication while maintaining system manageability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual login operations with an automated motion analysis system. Instead of requiring users to physically interact with a login interface, the system uses accelerometer data and computational algorithms (PCA, feature extraction) to automatically identify users based on their unique brushing patterns

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

2Measurement precision

If manual login methods are used for user identification, then device complexity is reduced, but identification accuracy deteriorates

Engineering Contradiction:
Improveidentification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual login with an automated motion recognition system using accelerometers and PCA analysis. The system captures six-degree-of-freedom motion data, extracts temporal and spatial features, and compares them against stored user profiles to achieve accurate automatic identification

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

Solution Approach 2:

The system continuously monitors toothbrushing motion patterns and provides feedback by comparing real-time data against stored user profiles. This feedback mechanism enables the system to accurately identify users and detect anomalies in brushing behavior

Inventive Principle:
Principle #23Feedback

3Measurement precision

If motion sensors are used to track toothbrush motion, then measurement precision is improved, but data processing complexity increases

Engineering Contradiction:
Improvemotion tracking accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the most relevant features from the six-degree-of-freedom motion data using PCA. Instead of processing all raw accelerometer data, the system identifies and extracts key temporal and spatial features that characterize user-specific brushing patterns, reducing computational complexity while maintaining accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the six-degree-of-freedom motion data into a reduced feature space using PCA. This parameter transformation converts complex multi-dimensional motion data into a smaller set of principal components that capture the essential variations in brushing patterns

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3920839B1Toothbrush motion analysis
Publication Date: 2024.03.06 UNILEVER GLOBAL IP LTD
  • EP3920839B1 patent drawingFigure 1
  • EP3920839B1 patent drawingFigure 2~3
  • EP3920839B1 patent drawingFigure 4~5

AI summary

A method of identifying a toothbrush user from among a plurality of different toothbrush users comprises obtaining data indicative of toothbrush motion relative to at least two axes of the toothbrush and filtering the motion data to extract motion data over a predetermined frequency range, such as within a predetermined frequency passband. A motion component distribution of the filtered motion data is determined, and the motion component distribution is compared with a plurality of user-specific motion component distributions to establish the data as indicative of one of said plurality of users. Toothbrushing data captured by a multi-user toothbrush motion tracking system can thereby be ascribed to a correct user within a cohort of users of the system.