Laser Thermography with multi-sensor capability for industrial robotic inspections

Introduction

Thermography has become a cornerstone in non-destructive testing (NDT), providing critical insights into surface conditions without compromising the integrity of the object under inspection. Among the many thermographic techniques, laser thermography stands out for its precision, adaptability, and depth of analysis—particularly when dealing with high-performance components, such as turbine blades.

When combined with robotic inspection systems and infrared sensors, laser thermography evolves into a robust solution capable of inspecting large, complex, and non-planar surfaces with remarkable efficiency and repeatability. In this article, we explore how this technology is implemented in industrial environments, focusing on the integration of laser excitation, automated motion systems, and intelligent evaluation algorithms to detect surface-breaking defects with high sensitivity.

Understanding Laser Thermography in industrial inspections

At its core, laser thermography uses a focused, high-power laser as a heat source to induce localized thermal excitation on the surface of the test object. As the laser irradiates the surface, any structural inconsistencies, such as surface-breaking cracks, will affect heat diffusion and manifest as thermal anomalies. A thermographic camera captured these in real time, typically equipped with infrared sensors, enabling precise thermal imaging.

Unlike conventional passive thermography, the active stimulation provided by laser sources allows for enhanced defect contrast and better control over excitation parameters. These can include the spot geometry, wavelength, and scanning strategy, each of which can be fine-tuned to suit the material properties and geometry of the component under inspection.

Multi-Sensor integration and infrared sensing capabilities

The integration of multi-sensor capabilities, primarily infrared sensors and laser beam control modules, has turned laser thermography into an intelligent inspection solution. These sensors work in tandem to capture high-resolution thermal data and provide feedback for dynamic adjustments to the laser excitation. The following image shows an advanced multi-sensor Radiometric Thermal Camera that groups 4 different data capture sensors. Source: ngeomap.cl.

By modulating excitation parameters in real time based on sensor input, the inspection system can adapt to material variations, surface coatings and curvature changes. This adaptability increases detection sensitivity while minimizing false positives, which is critical in industries such as aerospace and power generation, where component integrity is paramount.

Advanced algorithms for automatic defect detection

Capturing thermal data is only part of the inspection process: the real value lies in its interpretation. Advanced evaluation algorithms, often based on AI or machine learning techniques, analyze thermal signatures to differentiate between genuine surface defects and benign surface features. These algorithms take into account spatial and temporal temperature gradients, pattern recognition and statistical deviation analyses to provide accurate defect mapping.

Technological development in the field of industrial thermography continues to advance with increasingly specialized solutions designed to meet the growing demands of the production environment. One of the areas that has evolved the most is thermographic monitoring software, which today not only offers more powerful tools, but also greater ease of use and accessibility for a wide range of industrial sectors.

A new generation of thermographic analysis platforms has been specifically designed to integrate the key functionalities required by professionals in industries such as automotive, steel, mining, food and energy. This evolution responds directly to real market needs, bringing significant improvements in condition monitoring, process control, early fire detection, testing and research applications.

Among the outstanding features of these new generation solutions are:

• More accurate and configurable areas of interest (ROIs)
• Customized isotherms for different thermal scenarios
• Optimized alarm systems for rapid response to anomalies
• Automatic reports with detailed and exportable data
• Thermal histograms with higher analytical resolution

These tools have been developed with the accumulated experience of expert users in mind, ensuring that their functionality is practical, efficient and aligned with current industry best practice standards.

Robotic laser thermographic inspection for large area and non-flat systems

To maximize the efficiency and safety of these inspections, advanced robotic solutions are now integrated with laser scanning capabilities. Robotic systems equipped with high-resolution thermal imaging cameras and LiDAR or 3D laser mapping technology enable automated scanning of large areas, following programmed trajectories that ensure complete and systematic coverage. As, for example, in the case of wind power systems, the following figure shows a thermographic image where the thermographic scanning of a large area of a wind farm can be appreciated.

The operation and maintenance of wind farms faces a constant challenge: inspecting large-scale structures located in remote environments and subjected to variable environmental conditions. In this context, infrared thermography has established itself as a key tool for early detection of thermal faults and structural defects, especially in critical components such as wind turbine blades, nacelle and tower.

Aerial robotic thermography provides the industrial world with important advantages. Speed, safety and efficiency are significant when carrying out inspections on large structures and major construction sites, which will lead us to deliver diverse solutions in the industrial, energy and civil infrastructure sectors.

The ability of robotic systems to execute complex motion trajectories makes them ideal for inspecting non-flat industrial components, enabling high-performance inspections without sacrificing accuracy. The implementation of these systems in wind farms represents a breakthrough in the digital transformation of predictive maintenance, enabling proactive planning, reduced downtime and improved asset availability.

Automated inspection of power substations using mobile robots with thermography and laser scanning

Electrical substations are fundamental in the distribution and regulation of large-scale electrical flow. Due to the criticality of these nodes, their maintenance must be non-invasive, precise and performed as frequently as possible to anticipate failures that could compromise the continuity of service or cause major damage. Within this framework, infrared thermography applied by mobile robots represents a state-of-the-art technological solution.

The “trolley” type robots are designed to move autonomously or semi-autonomously within the substation, guided by digital maps or local precision GPS signals. They incorporate thermographic cameras calibrated to capture real-time infrared images, combined with laser scanners or LiDAR sensors to build three-dimensional models of the environment. A representative image of this type of inspection of an electrical substation is shown below.

• Continuous monitoring without human intervention: The robot can operate on a 24-hour scheduled basis, even in environments with high voltage or restricted access, minimizing personnel exposure.
• Detection of incipient faults: Highly sensitive overheating zones in transformers, circuit breakers, disconnectors, isolators or connections are identified with high sensitivity, before visible faults occur.
• Alarms and automatic report generation: The system can issue alerts if thermal anomalies exceeding preset thresholds are detected and generate technical reports with images, temperature data and exact location of the problem.
• Adaptability to the environment: Thanks to laser scanning, the robot adjusts its trajectory in real time to avoid obstacles, identify critical measurement points and adapt to topographical or structural site changes.

This type of intelligent inspection is part of the new era of digital maintenance, aligned with the principles of Industry 4.0 and remote management of energy infrastructures. Its implementation makes it possible to extend the useful life of equipment, reduce operating costs and improve the traceability of maintenance performed on critical assets.

Importance of laser robotic thermography in industry

The evolution of industrial inspection is marked by the integration of technologies that offer greater precision, safety and operational autonomy. Laser robotic thermography represents a key advance in non-destructive testing (NDT), allowing detailed thermal analysis of components without contact, without disassembly and with high repeatability. This technology, when combined with robotic platforms – aerial or terrestrial – provides important information in real time, even in hostile environments, difficult to access or where human risk is high.

The implementation of robotic thermography systems not only optimizes predictive maintenance processes, but also raises quality control standards, reduces operational downtime and improves data-driven technical decision making. Its applicability in sectors such as steel, mining, manufacturing, food, energy and refining makes it a cross-cutting tool with high impact on asset management.

Conclusions

The fusion of laser thermography, robotic inspection, and infrared sensing technologies is redefining the landscape of industrial inspections. This multi-sensor approach allows engineers and quality assurance teams to inspect complex, high-value components with unmatched accuracy and speed. As industries continue to demand more precise and automated inspection solutions, the role of intelligent, thermography-based systems will only grow.

By leveraging advanced sensors, robotic automation, and sophisticated data evaluation, laser thermography is poised to become a leading methodology in the field of predictive maintenance and structural health monitoring.

Integrate laser robotic thermography solutions today and transform your inspection strategy into a smarter, safer and more efficient model.

References

1. Busse, G. (2004). “Lock-in Thermography for Nondestructive Evaluation.” Infrared Physics & Technology, 43(3–5), 311–318
2. Wu, D., et al. (2019). “Automated Defect Detection in Laser Thermography Using Deep Learning.” NDT & E International, 107, 102144.
3. Pickering, S. G. (2015). “A Review of Recent Developments in the Application of Thermography to NDT.” NDT.net.
4. Chen, X., et al. (2022). “Robotic Infrared Thermographic Inspection System for Complex-Shaped Components.” IEEE Transactions on Industrial Electronics, 69(2), 1264–1275.