Occupant Awakening Detection Using Thermal Imaging and Motion

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Solution Overview

Problem

Existing methods for estimating a person's awakening level based on hand temperature are ineffective if the person shifts the position where they grip the handle, limiting their applicability.

Innovation Solution

An occupant state detection device that uses processing circuitry to acquire images and temperature data, detect motion and hand temperature, and estimate awakening levels regardless of the handle grip position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a finger temperature sensor is disposed at a fixed position on the steering wheel to acquire hand temperature, then the awakening level can be estimated based on hand temperature, but the temperature measurement fails when the driver's grip position shifts

Engineering Contradiction:

Improvehand temperature measurement accuracyVSAvoidgrip position adaptability

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical contact-based temperature sensor system with an optical imaging system. A temperature distribution image is captured using an imaging device (infrared camera) that detects thermal radiation from the driver's hand without physical contact. This substitution allows temperature measurement regardless of the driver's grip position on the steering wheel, resolving the contradiction between measurement precision and grip position adaptability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a contact-based temperature sensor is used on the steering wheel, then the device structure is simple, but the system cannot accurately detect hand temperature when the driver does not grip the wheel at the sensor location

Engineering Contradiction:

Improvesensor system structureVSAvoidtemperature detection reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical contact sensor with a non-contact optical temperature imaging system. The imaging device captures temperature distribution images of the driver's hand by detecting infrared radiation, eliminating the need for physical contact. This approach maintains relatively simple device structure while significantly improving temperature detection reliability, as the measurement is no longer dependent on the driver's grip position.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If the awakening level estimation relies solely on hand temperature from a fixed sensor position, then the estimation method is simple, but it becomes ineffective when the driver's hand position varies

Engineering Contradiction:

Improveestimation method complexityVSAvoidgrip position independence

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the fixed-position contact temperature sensing method with a non-contact temperature distribution imaging method. The imaging device captures the entire temperature distribution of the driver's hand, and the processing circuitry extracts hand temperature from the captured image regardless of the hand's position on the steering wheel. This substitution maintains relatively simple estimation logic while achieving grip position independence.

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 accurate estimation of awakening levels based on hand temperature and motion, regardless of the grip position, providing a more reliable solution for monitoring occupant states.

Implementation Method 1

acquire a temperature image indicating a temperature of a surface of a body of the occupant measured in a non-contact manner

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS12240469B2Occupant state detection device and occupant state detection method

Publication Date: 2025.03.04 MITSUBISHI ELECTRIC CORP

AI summary

Included are: a captured image acquiring unit to acquire a captured image obtained by imaging an occupant; a temperature image acquiring unit to acquire a temperature image indicating a temperature of a surface of a body of the occupant measured in a non-contact manner; a motion detection unit to detect a motion of the occupant on the basis of the captured image; a temperature detection unit to detect a temperature of a hand of the occupant on the basis of the temperature image; and an awakening level estimating unit to estimate an awakening level of the occupant on the basis of the motion of the occupant detected by the motion detection unit and the temperature of the hand of the occupant detected by the temperature detection unit.