Road Surface Measurement Using Line Light Projection

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Solution Overview

Problem

Existing methods for measuring road surface properties, such as smoothness and texture, require high-speed vehicle travel and rely on inertial platforms, limiting their applicability over short distances and preventing effective measurement at slower speeds or in transverse directions, and fail to adequately disperse water, leading to aquaplaning risks.

Innovation Solution

An apparatus that projects a line of light onto the carriageway, allowing measurements to be taken in multiple directions (parallel or oblique to the travel direction), enabling cross-correlation and data merging for improved signal-to-noise ratio and texture analysis, and estimates gradient changes without relying on inertial platforms, allowing operation at slower speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-speed vehicle travel is used with inertial platforms to measure road surface smoothness, then measurement precision is improved, but the device complexity and requirement for high speed increase, limiting applicability over short distances and at slower speeds

Engineering Contradiction:
Improveroad surface smoothness measurementVSAvoidinertial platform requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from the complex inertial platform system. By using a simple camera to capture road surface images and processing these images to extract smoothness parameters, the invention eliminates the need for accelerometers, inertial platforms, and high-speed travel requirements while maintaining measurement capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical inertial measurement system with an optical imaging system. Instead of using physical sensors to detect road surface variations, the system uses a camera to capture images and processes these images to determine smoothness parameters, substituting mechanical measurement with optical detection and computational analysis

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

2Ease of operation

If a single line of light is projected parallel to the direction of travel, then the measurement process is simple, but the signal-to-noise ratio is insufficient for accurate texture analysis

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoidsurface texture measurement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent merges multiple measurements taken at different orientations into a single comprehensive analysis. By projecting light lines in multiple directions (parallel and transverse to travel) and combining the resulting measurements, the system achieves both operational simplicity and high measurement precision for surface texture characterization

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent adds an additional measurement dimension by introducing transverse light line projections perpendicular to the direction of travel. This complementary measurement direction provides independent texture information that, when combined with parallel measurements, significantly improves the signal-to-noise ratio and measurement accuracy

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

3Device complexity

If the apparatus can only measure in the direction of travel, then the device complexity is reduced, but the adaptability to measure transverse or oblique surface properties is lost

Engineering Contradiction:
Improvemeasurement direction configurationVSAvoidmeasurement direction flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic measurement system where the light projection orientation can be varied. The apparatus can switch between projecting light lines parallel to the direction of travel and projecting them transverse or oblique to the direction of travel, allowing flexible adaptation to different measurement requirements without increasing device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal measurement system capable of measuring road surface properties in multiple directions using the same apparatus. The single camera and light source configuration can measure both longitudinal smoothness (parallel to travel) and transverse texture (perpendicular to travel), eliminating the need for separate measurement systems for different orientations

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

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 measurement of road surface properties at various speeds, including walking speed, and effectively disperses water, reducing aquaplaning risks by providing high-resolution data sets and gradient estimates, while being more versatile and efficient than prior systems.

Implementation Method 1

a light source arranged to illuminate the carriageway by projecting a line of light onto the carriageway

Methodology Applied
Scientific EffectLight projection: Light

Implementation Method 2

views the diffuse scatter from the surface with an optical detector

Methodology Applied
Scientific EffectDiffuse scatter: Scattering

Data Source

PatentEP2136177B1Apparatus for Measuring Carriageway Surface Properties
Publication Date: 2014.03.26 WDM
  • EP2136177B1 patent drawingFigure 1~2
  • EP2136177B1 patent drawingFigure 3a~3c
  • EP2136177B1 patent drawingFigure 4

AI summary

An apparatus for measuring surface properties of a carriageway or road, comprising a platform arranged to move over the carriageway, the platform carrying a light source arranged to illuminate the carriageway, and a detector arranged to receive light returning from the carriageway, characterised in that the light source projects a line of light onto the surface, the line of light being parallel to the direction of travel, and data representing light returning from the line of light is captured and stored. The displacement of the vehicle between two successive measurements is estimated from the cross-correlation of the two successively measured profiles.