Fatigue State Determination via Facial Surface Change Analysis

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Solution Overview

Problem

Current methods for determining human brain activity, such as electroencephalography and near infrared spectroscopy, require complex setups and limited conditions, making it difficult to easily assess physical and mental states like fatigue.

Innovation Solution

A fatigue state determination device that uses facial-surface change information, decomposed by singular value decomposition, principal component analysis, or independent component analysis, to determine brain function activation without the need for electrodes or probes, utilizing facial skin temperature or blood circulation data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electroencephalography or near infrared spectroscopy is used to determine brain activity, then measurement precision is improved, but device complexity and ease of operation deteriorate due to required preprocessing and electrode attachment

Engineering Contradiction:

Improvebrain activity measurement precisionVSAvoidmeasurement setup complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/electrical measurement system (electrodes, probes, complex sensors) with an optical imaging system that captures facial surface information non-invasively. This substitution eliminates the need for physical contact with the subject while maintaining measurement capability through image-based brain function activation detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an optical copy or representation of brain activity through facial surface changes. Instead of directly measuring electrical or optical signals from the brain, the system captures indirect visual evidence through facial imaging, which serves as a proxy for brain function activation states.

Inventive Principle:

Principle #26Copying

2Measurement precision

If electroencephalography or near infrared spectroscopy is used to determine brain activity, then measurement precision is improved, but ease of operation worsens due to preprocessing requirements

Engineering Contradiction:

Improvebrain activity measurement precisionVSAvoidmeasurement operation simplicity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces complex signal processing requirements with straightforward image capture and analysis. The optical imaging system naturally produces visual data that can be directly analyzed for facial surface changes, eliminating the need for sophisticated preprocessing pipelines required by electroencephalography and near infrared spectroscopy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The facial surface information serves as both the measurement target and the analysis source. The imaging system captures facial changes that inherently contain the brain function activation information needed, eliminating the need for separate preprocessing steps to extract meaningful signals from raw data.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If magnetic resonance imaging is used to determine brain activity, then measurement precision is improved, but device complexity and measurement conditions worsen due to requirement for predetermined MRI room

Engineering Contradiction:

Improvebrain activity measurement precisionVSAvoidmeasurement environment flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the specialized MRI imaging system with a standard optical imaging system that can operate in any environment. This substitution maintains measurement capability while eliminating the requirement for controlled MRI room conditions, enabling deployment in diverse settings such as workplaces and outdoor environments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical imaging system serves multiple functions: it captures facial surface information for brain function activation detection, works in various environments without special requirements, and can be integrated into different devices (smartphones, cameras, monitoring systems). This universality contrasts with the specialized MRI system that requires controlled environments.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If electroencephalography, near infrared spectroscopy, or magnetic resonance imaging is used, then measurement precision is improved, but cost worsens due to enormous costs required

Engineering Contradiction:

Improvebrain activity measurement precisionVSAvoidmeasurement cost

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent employs inexpensive optical imaging technology instead of costly specialized equipment. Standard cameras and image processing algorithms replace expensive MRI scanners, electroencephalography systems, and near infrared spectroscopy devices, dramatically reducing measurement costs while maintaining functional capability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes expensive medical-grade imaging systems with affordable optical imaging technology. This substitution maintains the ability to detect brain function activation through facial surface changes while eliminating the enormous costs associated with specialized equipment acquisition and operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 easy and accurate determination of fatigue state without the burden of complex setups, using non-invasive methods like infrared cameras or solid-state imaging devices, improving accessibility and reliability.

Implementation Method 1

The facial-surface change information decomposition unit decomposes the facial-surface change information into a plurality of components by singular value decomposition, principal component analysis, or independent component analysis

Methodology Applied

Scientific EffectSingular value decomposition:

Implementation Method 2

Methodology Applied

Scientific EffectPrincipal component analysis:

Implementation Method 3

Methodology Applied

Scientific EffectIndependent component analysis:

Implementation Method 4

using non-invasive methods like infrared cameras or solid-state imaging devices

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 5

using non-invasive methods like infrared cameras or solid-state imaging devices

Methodology Applied

Scientific EffectThermography: Thermography

Data Source

PatentUS11844613B2Fatigue state determination device and fatigue state determination method

Publication Date: 2023.12.19 DAIKIN INDUSTRIES LTD

AI summary

A fatigue state determination device and a fatigue state determination method determine a fatigue state of a subject. The fatigue state determination device includes a brain-function activation information provision unit and a fatigue state determination unit. The brain-function activation information provision unit provides brain-function activation information in order to activate a human brain function of a subject. The fatigue state determination unit determines a fatigue state of the subject based on facial-surface change information indicative of a time-series change of facial surface data on the subject while the brain-function activation information is being provided.