Road Marking Retroreflection Measurement Device

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Solution Overview

Problem

Existing devices for measuring the retroreflected luminance coefficient of road markings from a moving vehicle face challenges in precise positioning, high energy consumption, and limited measurement width due to the need for a narrow illuminated surface, making it difficult to maintain alignment and increasing battery power consumption.

Innovation Solution

The device projects multiple non-coherent light beams to illuminate a cumulative surface, which is strictly included within a convex envelope, reducing energy consumption and allowing for a wider measurement area without increasing the illuminated surface, using electronic switching and multiple light sources to minimize power usage and enhance precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a narrow illuminated surface is used to reduce energy consumption, then instantaneous power consumption is reduced, but measurement width is limited and alignment precision becomes difficult to maintain

Engineering Contradiction:
Improveinstantaneous power consumptionVSAvoidalignment maintenance difficulty
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent divides the illumination into multiple separate light beams that illuminate distinct elementary surfaces along the road marking. This segmentation allows the system to cover a wider measurement area without requiring a single large illuminated surface, thereby maintaining lower power consumption while improving alignment robustness through distributed measurement points

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single narrow illuminated surface to multiple illuminated surfaces distributed along the road marking in the longitudinal dimension. This dimensional expansion allows wider effective measurement coverage while keeping each individual illuminated surface narrow enough to maintain low instantaneous power consumption

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If multiple light beams are projected to illuminate multiple elementary surfaces, then measurement width increases and alignment robustness improves, but instantaneous power consumption increases

Engineering Contradiction:
Improvealignment robustnessVSAvoidinstantaneous power consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic activation of multiple light beams rather than continuous illumination of a single large surface. By sequentially or periodically activating beams to illuminate different elementary surfaces, the system achieves wide measurement coverage and improved alignment robustness while limiting the instantaneous power consumption at any given moment

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The illumination system is segmented into multiple independent light beams that can be activated selectively. This segmentation enables the system to distribute the power consumption across time and space, achieving robust wide-area measurement without requiring high instantaneous power for a single large illuminated surface

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the illuminated surface width is increased to simplify driver alignment, then alignment difficulty is reduced, but the area to be illuminated and power consumption increase

Engineering Contradiction:
Improvedriver alignment easeVSAvoidpower consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent segments the illumination into multiple narrow beams distributed along the road marking rather than using a single wide beam. This segmentation allows the effective measurement width to be increased (improving alignment ease) while each individual beam remains narrow, keeping the power consumption for each beam low and the total instantaneous power consumption controlled

Inventive Principle:
Principle #1Segmentation

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 reduces instantaneous power consumption, allows for a wider measurement area, and maintains high precision by distributing energy efficiently and ensuring that only marked surfaces contribute to the measurement, thereby simplifying driver alignment and extending battery life.

Implementation Method 1

a device for emitting and projecting a light beam in light not coherent, capable of projecting a light beam towards a measurement surface

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

Following this illumination, the illuminated surface struck by the incident light beam emits radiation called reflected radiation. In a second step, acquisition means of the measuring device carry out the acquisition of a part of this reflected radiation which returns to the rear

Methodology Applied
Scientific EffectRetro-reflection: Reflection

Data Source

PatentEP2159568B1Device and method for measuring the retro-reflected luminance coefficient of road markings
Publication Date: 2012.08.01 INST FR DES SCI & TECH
  • EP2159568B1 patent drawingFigure 1
  • EP2159568B1 patent drawingFigure 2
  • EP2159568B1 patent drawingFigure 3~7

AI summary

The device (10) has a light beam emitting and projecting device (34) provided with eight LEDs, for emitting and projecting light beams illuminating respective elementary illuminated surfaces during measurement of retroreflected luminance coefficient of road markings (28, 32) at a measurement place (38). The elementary illuminated surfaces are strictly included in a cumulated illuminated surface at each instant, during the measurement of the luminance coefficient of the road markings. An independent claim is also included for a method for measuring a retroreflected luminance coefficient of road markings at successive measurement places.