Pavement Crack Detection via Thermal Imaging

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Solution Overview

Problem

Current methods for evaluating the condition of pavements are unreliable due to variability in professional skill and inability to accurately detect micro and macro cracks, which affect water infiltration and pavement damage, especially in bitumen pavements.

Innovation Solution

A method using temperature measurements with precision thermal cameras or thermal scanners to detect temperature differences between heavily and lightly loaded areas of pavements, indicating the presence of cracks, combined with location data and optional ground-penetrating radar for thickness measurement, to assess the need for repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If visual examination by professionals is used to evaluate pavement condition, then the evaluation can be performed directly in the field, but the reliability of the result varies a lot according to professional skill

Engineering Contradiction:
Improvefield evaluation capabilityVSAvoidevaluation reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the manual visual examination method with an automated thermal imaging system. The thermal camera captures temperature distributions on the pavement surface, and image processing algorithms automatically analyze these thermal patterns to detect cracks and evaluate pavement condition, eliminating dependence on professional skill while maintaining field evaluation capability

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

Solution Approach 2:

The patent introduces thermal imaging technology as an intermediary between the pavement condition and the evaluation result. The thermal camera acts as a mediator that converts invisible structural issues (cracks, water infiltration) into visible thermal patterns, which can then be objectively analyzed without human subjectivity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If ground-penetrating radar is used to measure pavement thickness, then thickness information is obtained, but this does not always correlate directly with the amount of micro and macro cracks

Engineering Contradiction:
Improvepavement structure informationVSAvoidcrack detection accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from physical thickness (measured by GPR) to thermal characteristics (measured by thermal camera). Since cracks and water infiltration alter the thermal properties of pavement, this parameter change enables direct detection of structural defects that thickness measurements cannot reveal

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses thermal imaging to create a visual representation of pavement condition through temperature color coding. Cracks and water-saturated areas appear as distinct thermal patterns (different colors) on the thermal image, making invisible structural issues visible and directly correlatable with pavement defects

Inventive Principle:
Principle #32Color changes

3Reliability

If thermal imaging is used to detect temperature differences indicating cracks, then early detection of pavement damage is enabled, but the method requires precise temperature measurement capability

Engineering Contradiction:
Improvedamage detection reliabilityVSAvoidtemperature measurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary thermal imaging measurements to detect temperature differences before pavement damage becomes severe. By continuously monitoring thermal patterns and comparing them against reference conditions, the system can identify early signs of cracking and water infiltration, enabling preventive maintenance before structural failure occurs

Inventive Principle:
Principle #10Preliminary action

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 early detection of pavement damage, providing a more reliable evaluation and allowing for preventive maintenance, reducing the formation of further damages through improved water-tightness and coating, and facilitating quick, inexpensive assessments of long road stretches.

Implementation Method 1

an apparatus for evaluating the condition of the pavement of a traffic lane comprising temperature measuring means, with which temperature measuring means the temperature or the emissivity of a heavily loaded part of the pavement and the temperature or the emissivity of a lightly loaded part of the pavement can be measured

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP2327976B1Method and apparatus for evaluating the condition of the pavement of a traffic lane
Publication Date: 2019.06.19 ROADSCANNERS HLDG
  • EP2327976B1 patent drawingFigure 1
  • EP2327976B1 patent drawingFigure 2a~2b

AI summary

The method is meant for the evaluating of the amount of micro and macro cracks in the pavement of a traffic lane, such as a road or street. The colder water beneath the pavement is under the load of heavy traffic pumped into the micro and macro cracks in the pavement and lowers the temperature of the pavement, so a large difference between the temperatures in different points on the pavement reveals a large amount of cracks. In the method, the examination span of the traffic lane is first selected. Thereafter the temperature T1 of the heavily loaded part of the pavement of the selected examination span and the temperature T2 of the lightly loaded part of the pavement of the same examination span are determined. A difference AT between the determined temperatures is calculated, which difference is compared to a reference value. If the difference is larger than the used reference value, the pavement lets through a significant amount of water. If the difference is smaller than the used reference value, the condition of the pavement is sufficiently good. The temperatures tr of the heavily loaded part of the pavement are measured at the wheel ruts and the temperatures tk of the lightly loaded part of the pavement are measured in the area outside the wheel ruts. The temperatures of the pavement are measured with an apparatus, which is placed in a vehicle travelling on the traffic lane. Alternatively the emissivity εr of the heavily loaded part of the pavement and the emissivity εk of the lightly loaded part of the pavement can be determined and the difference Δε can be compared to a reference value.