Road Marking Differentiation Using Color and Relative Position

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Solution Overview

Problem

Infrared or near-infrared cameras used in vehicles cannot differentiate between primary and secondary road markings, such as white and yellow markings, leading to incorrect detection and execution of intended functions.

Innovation Solution

A method utilizing a primary camera operating in the visible spectrum to capture color images of primary and secondary road markings, combined with one or more infrared or near-infrared secondary cameras, and an electronic control unit to determine the relative positions and colors of these markings, enabling differentiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If road markings are applied to existing roads to indicate alternative routes, then traffic guidance is provided, but the markings become indistinguishable from original road markings making them undetectable by autonomous vehicles

Engineering Contradiction:
Improvetraffic guidance capabilityVSAvoidmarking detectability
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies a fluorescent or phosphorescent coating to the secondary road marking material, causing it to reflect or emit light differently from the primary road marking material. This color/optical property change enables autonomous vehicles to distinguish between primary and secondary markings through optical sensors, resolving the detectability issue while maintaining traffic guidance functionality

Inventive Principle:
Principle #32Color changes

2Illumination intensity

If reflective materials are used for road markings to enhance visibility, then marking visibility is improved, but the cost of materials and application increases

Engineering Contradiction:
Improvemarking visibilityVSAvoidmaterial cost
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent applies the fluorescent or phosphorescent coating only to the secondary road markings rather than all road markings uniformly. This localized application enhances visibility specifically where needed for alternative route guidance while minimizing material costs compared to treating the entire road surface with expensive reflective materials

Inventive Principle:
Principle #3Local quality

3Loss of information

If additional road markings are added to indicate alternative routes, then navigation information is provided, but the complexity of the marking system increases

Engineering Contradiction:
Improvenavigation informationVSAvoidmarking system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent uses optical property changes (fluorescent/phosphorescent coating) to encode navigation information directly into the marking appearance itself, rather than requiring complex multi-component systems. The different optical response of secondary markings provides clear navigation guidance while keeping the overall system simpler than alternative approaches using multiple colors, shapes, or layered markings

Inventive Principle:
Principle #32Color changes

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 differentiation between primary and secondary road markings, allowing vehicles to correctly follow the appropriate markings for functions like parking, lane changing, and lane keeping, while complying with regulations by avoiding visible light illumination.

Implementation Method 1

The secondary road marking material may be coated with a fluorescent or phosphorescent coating

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

The secondary road marking material may be coated with a fluorescent or phosphorescent coating

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP4217913B1Method for differentiating a secondary road marking from a primary road marking
Publication Date: 2026.04.29 VALEO VISION SA
  • EP4217913B1 patent drawingFigure 1a
  • EP4217913B1 patent drawingFigure 1b
  • EP4217913B1 patent drawingFigure 2

AI summary

The invention relates to a method for differentiating a secondary road marking from a primary road marking, comprising: - acquiring primary images of the environment of a vehicle to the front or to the rear, by means of a primary camera, including images of the primary road marking and the secondary road marking which are located to the front or to the rear, - acquiring secondary images of the environment on one side of the vehicle, by means of a secondary camera, comprising images of the primary road marking and the secondary road marking which are located on said side, - determining, by means of the primary camera, from the primary images, the primary colour of the primary road marking and the secondary colour of the secondary road marking, - transmitting, by means of the primary camera to a control unit, a primary position vector of the primary marking with its primary colour, and a secondary position vector of the secondary marking with its secondary colour, as inferred from the primary images, - transmitting, by means of the secondary camera to the control unit, a primary position vector of the primary road marking and a secondary position vector of the secondary road marking, as inferred from the secondary images, - determining a relative position vector of the secondary road marking with respect to the primary road marking in the secondary field of vision of the secondary camera from the primary and secondary position vectors, - making a correlation between the secondary colour and the relative position vector.