Non-contact Brain Activity Estimation via Facial Skin Temperature

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Solution Overview

Problem

Existing devices for estimating brain activity require complex preparation and burden subjects with electrode attachment and limited measurement conditions, making it difficult to easily and accurately assess brain activity.

Innovation Solution

An evaluation device that uses facial skin temperature and facial blood circulation volume data, acquired through non-invasive means like infrared thermography and RGB image processing, to estimate brain activity without the need for electroencephalogram electrodes or other sensors, employing singular value decomposition to identify components correlated with brain activation and resting states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electroencephalogram electrodes are used to estimate brain activity, then measurement precision is improved, but device complexity and ease of operation deteriorate due to complex preparation work and electrode attachment requirements

Engineering Contradiction:
Improvebrain activity measurement precisionVSAvoidease of brain activity estimation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical electrode attachment system with an optical imaging system. Instead of using electroencephalogram electrodes that require physical contact and complex preparation, the invention uses infrared cameras to capture thermal images and RGB cameras to capture blood circulation images of the facial surface, thereby estimating brain activity through non-contact optical methods.

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

Solution Approach 2:

The patent introduces facial surface characteristics (skin temperature and blood circulation volume) as intermediary parameters between the brain activity and the measurement device. By measuring these intermediary parameters on the facial surface, the system indirectly estimates brain activity without requiring direct brain contact or complex electrode setup.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If electroencephalogram electrodes are used to estimate brain activity, then measurement precision is improved, but device complexity worsens due to pretreatment requirements and limited measurement conditions

Engineering Contradiction:
Improvebrain activity measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical electrode attachment system with an optical imaging system. Instead of using electroencephalogram electrodes that require physical contact and complex preparation, the invention uses infrared cameras to capture thermal images and RGB cameras to capture blood circulation images of the facial surface, thereby estimating brain activity through non-contact optical methods.

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

Solution Approach 2:

The patent employs a camera system that can perform multiple functions: capturing thermal images for skin temperature measurement, capturing RGB images for blood circulation volume measurement, and providing visual records. This multi-functional approach reduces device complexity compared to specialized electroencephalogram equipment.

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

3Ease of operation

If facial skin temperature and blood circulation volume data are used to estimate brain activity, then ease of operation is improved, but measurement precision may deteriorate

Engineering Contradiction:
Improveease of brain activity estimationVSAvoidbrain activity measurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the facial surface into multiple measurement regions (forehead, between eyebrows, around paranasal sinuses, around mouth) and collects temperature and blood circulation data from each region. By analyzing multiple segmented regions rather than a single point, the system improves measurement precision while maintaining ease of operation through automated multi-region monitoring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies singular value decomposition to the collected facial data to identify components that correlate with brain activation and resting states. This feedback mechanism processes the raw temperature and blood circulation data to extract meaningful brain activity indicators, thereby improving measurement precision through systematic data analysis.

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

Enables easy and accurate estimation of brain activity without subject burden, allowing for the evaluation of interest levels in subjects, facilitating market research and learning evaluations by analyzing brain activity through non-contact methods.

Implementation Method 1

facial skin temperature acquisition means acquire facial skin temperature data in time-series... Photographic image data of the facial surface of the subject is captured and subjected to RGB processing in time-series

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

The facial blood circulation volume data is acquired on the basis of RGB data of the photographic image data obtained from the RGB processing

Methodology Applied
Scientific EffectRGB color processing: Image Processing

Data Source

PatentEP3364361B1Evaluation device, market research device, and learning evaluation device
Publication Date: 2023.12.20 DAIKIN INDUSTRIES LTD
  • EP3364361B1 patent drawingFigure 1(a)~1(b)
  • EP3364361B1 patent drawingFigure 2(a)~2(b)
  • EP3364361B1 patent drawingFigure 3(a)~3(b)

AI summary

An evaluation device 10 includes facial skin temperature acquisition means 20, brain activity estimation means 30, and evaluation means 200. The facial skin temperature acquisition means 20 acquire facial skin temperature data in time-series. The facial skin temperature data includes skin temperature data detected from the facial surface of the subject and position data of the detection site of the skin temperature data. The brain activity estimation means 30 obtain a plurality of components by decomposing the facial skin temperature data by singular value decomposition, principal component analysis, or independent component analysis, and then estimate the brain activity of the subject on the basis of this plurality of components. The evaluation means 200 evaluate the degree of interest of the subject on the basis of the brain activity of the subject estimated by the brain activity estimation means 30.