Driver State Detection Using Ambient Brightness Sensors

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Solution Overview

Problem

Existing methods for determining a driver's tiredness or state rely on time-dependent circadian rhythm evaluations, which can be inaccurate due to geographic and seasonal variations in brightness, leading to suboptimal assessments.

Innovation Solution

A method that determines a driver's state independently of time using brightness measurements from sensors, incorporating additional variables like driving behavior and physiological data, with a time filter to weight short-term changes, ensuring a more accurate and time-independent assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time-dependent circadian rhythm evaluations are used to determine driver state, then driver tiredness can be assessed, but geographic and seasonal variations in brightness cause inaccuracies in the assessment

Engineering Contradiction:
Improvedriver state assessment accuracyVSAvoidadaptability to geographic and seasonal variations
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the assessment parameter from time-based (circadian rhythm) to brightness-based (ambient light exposure). By using brightness sensors to measure actual light conditions and comparing them against expected values, the system adapts to different geographic locations and seasonal variations, eliminating inaccuracies caused by using fixed time-based models in variable environmental conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/time-based circadian rhythm evaluation system with an optical sensing system that directly measures ambient brightness. This substitution allows the system to detect actual light conditions rather than relying on clock values, enabling accurate driver state assessment across different geographic and seasonal contexts

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

2Ease of operation

If Central European clock value-brightness value correlations are used as a basis for determining driver state, then driver tiredness can be determined, but discrepancies occur in regions with different geographic latitudes and time zones

Engineering Contradiction:
Improvedriver state determinationVSAvoidapplicability across different geographic regions
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal brightness-based assessment system that functions across all geographic regions and time zones. By using ambient brightness measurements rather than location-specific time correlations, the system achieves multi-functionality and universal applicability, automatically adapting to different geographic latitudes, seasonal variations, and time zones without requiring region-specific calibration

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

Solution Approach 2:

Instead of determining expected brightness from clock values (top-down approach), the system inverts the logic by measuring actual brightness and using it to assess driver state directly (bottom-up approach). This inversion eliminates the need for pre-defined correlations between time and brightness, allowing the system to work universally across all geographic conditions

Inventive Principle:
Principle #13The other way round (Inversion)

3Speed

If short-term brightness changes (e.g., tunnels, storms) are immediately reflected in driver state determination, then rapid environmental changes are detected, but false indications of driver tiredness occur

Engineering Contradiction:
Improveresponse to brightness changesVSAvoiddriver tiredness indication accuracy
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies preliminary filtering action by comparing actual brightness measurements against expected brightness values before determining driver state. The evaluation unit assesses whether deviations from expected brightness are significant and sustained, filtering out transient changes caused by tunnels or storms. This preliminary evaluation prevents false tiredness indications while still detecting genuine driver state changes

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by continuously comparing actual brightness measurements with expected brightness values and adjusting the driver state assessment accordingly. When short-term deviations occur, the feedback mechanism evaluates whether they represent genuine changes in driver condition or transient environmental effects, thereby maintaining reliable tiredness indication while responding to meaningful brightness changes

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

This approach avoids errors caused by incorrect time-based evaluations and considers atypical brightness conditions, providing a more precise and reliable determination of driver tiredness and state, accounting for various factors such as driving behavior and physiological states.

Implementation Method 1

the brightness is determined by means of a sensor

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2856447B1Method and device for recognising the condition of a driver
Publication Date: 2019.01.16 ROBERT BOSCH GMBH
  • EP2856447B1 patent drawingFigure 1
  • EP2856447B1 patent drawingFigure 2

AI summary

The invention relates to a method for determining a variable that represents the condition of a driver of a vehicle, said variable being determined independently of the time of day at least using another variable representing the light intensity to which the driver is exposed.