Driver Monitoring Gaze Range Control During Steering

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Solution Overview

Problem

Conventional driver state detection devices inaccurately judge a driver as distracted when information on the road shape is unavailable or when a turn signal is not operated, leading to false positives during steering wheel adjustments.

Innovation Solution

A driver state detection device that uses a driver monitor camera and control device to detect facial orientation and line-of-sight direction, adjusting the allowable range based on steering wheel operations and vehicle speed to accurately distinguish between distracted and non-distracted driving, especially in curved sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the allowable range is expanded by a predetermined amount based on road shape information, then the accuracy of distracted driving detection is improved, but the system cannot handle cases where road shape information is unavailable

Engineering Contradiction:
Improvedistracted driving detection accuracyVSAvoidhandling capability when road information is unavailable
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter basis for allowable range expansion from road shape information to steering wheel operation information. When road shape information is unavailable, the system uses steering angle and steering speed to dynamically determine the allowable range, ensuring continuous adaptability without requiring external road data.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces steering wheel operation information as an intermediary parameter to bridge the gap when road shape information is unavailable. The steering information serves as a substitute mediator that allows the system to maintain accurate distracted driving detection without direct road shape data.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the allowable range is expanded based on turn signal operation, then lane change scenarios are handled better, but false positives occur when steering wheel is operated without turn signal

Engineering Contradiction:
Improvelane change scenario handlingVSAvoiddistracted driving detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent makes the allowable range dynamically adjustable based on real-time steering wheel operation characteristics. Instead of using static turn signal states, the system continuously adapts the allowable range according to steering angle and steering speed, accurately reflecting the driver's actual vehicle control intentions and eliminating false positives.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the driving scenario into multiple states based on steering operation characteristics (steering angle thresholds, steering speed thresholds). By dividing the continuous steering operation into discrete segments, the system can apply different allowable range expansion strategies for different steering intensities, improving both adaptability and precision.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If a fixed expansion amount is used for allowable range, then the system is simple to implement, but it cannot accurately adapt to different steering intensities and speeds

Engineering Contradiction:
Improvesystem implementation simplicityVSAvoidallowable range adaptability
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transforms the static fixed expansion amount into a dynamic variable that changes with steering operation intensity and vehicle speed. The allowable range expansion is no longer a constant value but is calculated based on real-time steering angle, steering speed, and vehicle speed, enabling accurate adaptation to different driving conditions while maintaining reasonable system complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4403396B1Driver state detection device
Publication Date: 2025.08.27 TOYOTA JIDOSHA KK
  • EP4403396B1 patent drawingFigure 1
  • EP4403396B1 patent drawingFigure 2
  • EP4403396B1 patent drawingFigure 3A~3B

AI summary

A driver state detection device (100) provided with a driver monitor camera configured to capture the face of a driver of a vehicle to generate a facial image of the driver and a control device (4). The control device (4) is configured to detect the facial orientation or the line-of-sight direction of the driver based on the facial image, judge that the driver is driving distracted when the facial orientation or the line-of-sight direction of the driver is maintained for greater than or equal to a predetermined time period at the outside from the allowable range allowed as the facial orientation or the line-of-sight direction of the driver, and set the allowable range based on an operating parameter which is in a correlative relationship with steering operation of the steering wheel of the vehicle and the speed of the vehicle.