Tunnel Entrance Illumination Calculation Using Visual Recognition

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Solution Overview

Problem

Current highway tunnel illumination designs for daytime tunnel entrance sections are inadequate as they solely focus on brightness index, neglecting light source characteristics like color temperature and color rendering index, leading to 'black hole' effects and visual recognition difficulties for drivers, which can cause traffic accidents.

Innovation Solution

A dynamic illumination standard calculation method and system that considers color temperature, color rendering index, and average road surface brightness to ensure safe visual recognition, using a combination of dynamic and static measurement techniques to establish a reliable and comfortable light environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If only brightness index is considered in tunnel entrance section illumination design, then the design is simple, but the visual recognition safety is insufficient

Engineering Contradiction:
Improveillumination design complexityVSAvoidvisual recognition safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent extends the illumination evaluation from a single brightness parameter to multiple parameters including brightness, color temperature, and color rendering index. This multi-parameter approach comprehensively characterizes the light environment, enabling more accurate assessment of visual recognition conditions while maintaining manageable design complexity through systematic parameter integration.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If static measuring methods are used to study illumination characteristics, then the measurement process is simple, but the reliability of research results is limited

Engineering Contradiction:
Improvemeasurement operation simplicityVSAvoidresearch result reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent transitions from static measurement to dynamic measurement that tracks illumination characteristics and visual recognition conditions throughout the tunnel entrance section. The system measures parameters at multiple positions and under varying conditions, capturing the dynamic nature of light environments and their impact on driver visual adaptation, thereby significantly improving result reliability.

Inventive Principle:
Principle #15Dynamics

3Reliability

If comprehensive illumination standards considering multiple parameters are established, then visual recognition safety is improved, but the measurement and calculation system becomes more complex

Engineering Contradiction:
Improvevisual recognition safetyVSAvoidmeasurement system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent develops an integrated measurement and calculation system that simultaneously measures multiple illumination parameters (brightness, color temperature, color rendering index) and performs comprehensive safety evaluation functions. This multi-functional system consolidates what would otherwise require separate measurement devices and analysis processes, managing complexity through unified system architecture.

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

4Use of energy by stationary object

If illumination design focuses only on brightness, then energy consumption is reduced, but driver visual adaptation and safety are compromised

Engineering Contradiction:
Improveillumination energy consumptionVSAvoiddriver visual adaptation
Core Design Contradiction:
Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent optimizes illumination by adjusting multiple parameters including color temperature and color rendering index in addition to brightness. This allows for more efficient light environments that improve visual adaptation without simply increasing overall brightness, thereby managing energy consumption more effectively while enhancing driver safety and comfort.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3187850B1Safe visual recognition-based method for standard measurement/calculation of daytime tunnel entrance section illumination, and system thereof
Publication Date: 2021.12.08 BEIJING UNIV OF TECH
  • EP3187850B1 patent drawingFigure 1~2
  • EP3187850B1 patent drawingFigure 3
  • EP3187850B1 patent drawingFigure 4

AI summary

The invention relates to an illumination standard calculation method for a tunnel entrance section in daytime based on safe visual recognition. The method includes: (a) setting light environment parameters of the tunnel entrance section; (b) determining a feature position in the tunnel, and measuring the average road surface brightness L of the feature position; (c) placing a target object in the feature position and then making a driver drive at different speeds from outside the tunnel towards the target object to measure visual recognition distances D required by the driver to visually discover the target object under different driving speeds, and measuring the road surface brightness L20 at the position where the driver visually discovers the target object and calculating the brightness reduction factor K to be the ratio between L and L20; (d) resetting the average road surface brightness L of the tunnel entrance section and repeating steps (b) and (c) to obtain a plurality of different sets of visual recognition distances D and corresponding brightness reduction factors K; (e) using Sigmoid function model to calculate and fit the data of the plurality of sets of D and K to obtain a relational model formula of D and K: D=2151+e−70K+96+27.6; (f) substituting a safe stopping sight distance D0 corresponding to a maximum speed limit of the tunnel into the formula to obtain the minimum brightness reduction factor K0 of the tunnel entrance section in daytime. The invention also relates to a system for implementing the illumination standard calculation method for a tunnel entrance section in daytime based on safe visual recognition.