Thermal Imaging Technology Research Articles

Self-healing and in-situ real-time damage-reporting fiber-reinforced composite

To increase the service life of composite materials, self-healing, and damage detection are essential. Although a lot of research has been done on self-healing and damage-reporting materials, it is still difficult to combine self-healing with in-situ and real-time damage detection in bulk resin and composites. By integrating extrinsic self-healing based on microcapsules and internal self-healing based on coordination interaction, the simultaneous self-healing of matrix and interface damage of fiber-reinforced composites was achieved in this study. Specifically, two-component microcapsules filled with epoxy/mercaptan repair agent were inserted into the matrix and Ag nanoparticles (AgNPs) were introduced into the surface of carbon fiber by electroless plating. Upon the rupture of microcapsules, matrix self-healing was used to reach a desirable level of synchronous healing efficiency. In the meantime, the excess sulfhydryl reacted with AgNPs on the fibers to establish a coordination bond for interface self-healing. More intriguingly, the high exothermic action of epoxy resin and mercaptan repair agent in the self-healing process was observed when using infrared thermal imaging technology for in-situ and real-time damage detection.

SafeCross: Helping Elder People Cross the Road Timely Using Thermal Imaging and Image Recognition

Some older adults face challenges of cross the road in time due to reduced mobility and declining sensory abilities. Existing technologies have limitations in accurately identifying pedestrians. We propose SafeCross, a novel system that combines image recognition and thermal imaging technology based on the FLIR TrafiOne 156 sensor, which accurately detects elderly individuals at road intersections in low visibility or obstructed conditions and implement traffic light control based on the algorithm provided by SafeCross. Our findings demonstrate the potential of SafeCross system ensures safety for older adults at intersections, Making a significant contribution to reducing the accident rate among the elderly.

Study on the Specific Expression of Infrared Radiation Temperature on the Body Surface of Acupoint in Rats with Chronic Myocardial Ischemic Injury.

Infrared thermal imaging technology was used to observe the changes in infrared radiation temperature at acupoints in rats caused by chronic myocardial ischemia injury. This study aims to compare the difference of body surface infrared radiation temperature information of three groups of acupoints: bilateral Neiguan (PC6), bilateral Yanglingquan (GB33), and bilateral Sham Acupoints (SA) in the pathological state of myocardial ischemia injury, and to explore the relationship between acupoints and viscera state. SPF adult Wistar male rats (n = 20) were randomly divided into a control (CTL; n = 10) and an isoproterenol group (ISO; n = 10). Chronic myocardial injury was induced in rats by subcutaneous injection of isoproterenol hydrochloride for 14 d. On the second day after the establishment of the model, the serum levels of cardiac troponin (cTnI) and creatine kinase isoenzyme (CK-MB) were measured by enzyme-linked immunosorbent assay (ELISA). The morphological changes of the myocardial tissue in the two groups were observed by hematoxylin-eosin (HE) staining and their pathological scores were evaluated, which was then used to determine the myocardial ischemic injury. Two days before and after the establishment of the model, the electrocardiograms (ECG) of the two groups of rats were recorded by the (ECG) data acquisition system, and the infrared thermal imaging platform was used to detect the temperature of the six acupoints. 1. After subcutaneous injection of isoproterenol hydrochloride for 14 days, the ST segment of the ECG decreased in the ISO group compared with that of the CTL group; 2. Myocardial tissue injury was serious in the ISO group compared to the CTL group; 3. Serum cTn-I and CK-MB were significantly increased (P <0 01) in the ISO group, compared to that in the CTL group; 4. The infrared radiation temperature on the body surface of bilateral Neiguan (PC6) acupoints decreased significantly in the ISO group, compared to that of the CTL group. Infrared thermal imaging technology can be used to detect the changes in the energy state of acupoints. Chronic myocardial ischemic injury can cause a decrease in IR temperature on the body surface of bilateral Neiguan (PC6) acupoints, suggesting that visceral diseases can lead to changes in the energy metabolism of acupoints.

Evaluating the strength properties of standing trees through fractometry

In recent years, significant advancements in non-destructive testing (NDT) methodologies have emerged, with applications spanning various domains, including structural wood quality assessment and planted tree characteristic evaluation. Within the context of planted trees, a range of non-destructive and semi-destructive techniques have been developed to assess the extent of degradation in tree trunks. In this study, various mechanical characteristics of brutian pine (Pinus brutia Ten.) trees near the Ertokuş Madrasah in the Atabey district of the province of Isparta are examined. Beside their historical significance, these trees are notable for the potential risk they present in terms of leaning towards the madrasah facade and the risk of falling over. To achieve the goals of research, the resistance characteristics of incremental cores were systematically determined by using a thermal imaging camera in conjunction with a portable, non-destructive testing device called a Fractometer. Totally 15 incremental auger specimens were obtained by extracting three increment core samples, each with a thickness of 5 mm, from the trunks of five distinct trees, all at a consistent height of 1.3 meters above ground level. Bending and compressive strength measurements were recorded at intervals of 6 mm from the core to the outermost layer. Furthermore, the moisture content of the incremental cores was assessed using thermal imaging technology. Following an analysis of the collected data, it was concluded that the mechanical properties of the investigated brutian pine trees within an acceptable range.

Progress in Active Infrared Imaging for Defect Detection in the Renewable and Electronic Industries.

In recent years, infrared thermographic (IRT) technology has experienced notable advancements and found widespread applications in various fields, such as renewable industry, electronic industry, construction, aviation, and healthcare. IRT technology is used for defect detection due to its non-contact, efficient, and high-resolution methods, which enhance product quality and reliability. This review offers an overview of active IRT principles. It comprehensively examines four categories based on the type of heat sources employed: pulsed thermography (PT), lock-in thermography (LT), ultrasonically stimulated vibration thermography (UVT), and eddy current thermography (ECT). Furthermore, the review explores the application of IRT imaging in the renewable energy sector, with a specific focus on the photovoltaic (PV) industry. The integration of IRT imaging and deep learning techniques presents an efficient and highly accurate solution for detecting defects in PV panels, playing a critical role in monitoring and maintaining PV energy systems. In addition, the application of infrared thermal imaging technology in electronic industry is reviewed. In the development and manufacturing of electronic products, IRT imaging is used to assess the performance and thermal characteristics of circuit boards. It aids in detecting potential material and manufacturing defects, ensuring product quality. Furthermore, the research discusses algorithmic detection for PV panels, the excitation sources used in electronic industry inspections, and infrared wavelengths. Finally, the review analyzes the advantages and challenges of IRT imaging concerning excitation sources, the PV industry, the electronics industry, and artificial intelligence (AI). It provides insights into critical issues requiring attention in future research endeavors.

Seamless real-time thermal imaging system with ESP8266: wireless data transfer and display using UDP

Thermal imaging technology has become increasingly popular for various applications, including industrial monitoring, building automation, and medical diagnostics. However, existing thermal imaging systems often come with high costs and limited connectivity options. In this paper, we propose a method to address these challenges by utilizing the ESP8266 microcontroller to create a thermal imaging system that can measure thermal pixel values, transfer the data wirelessly using the ESP8266’s networking capabilities and display the pixel data in real-time on a Thin-film-transistor liquid-crystal (TFT) display. The objective is to establish a seamless and real-time transfer of thermal images within a local network environment. User datagram protocol (UDP) supports transmission via broadcast and multicast, making it highly efficient for delivering data to multiple clients or devices on a network. It allows a single UDP packet to be simultaneously sent to multiple destinations, enhancing its effectiveness. This feature simplifies the implementation of network protocols and applications, reducing their overall complexity. UDP is particularly well-suited for devices with limited resources, such as microcontrollers or embedded systems, where memory and computing power are constrained. Experimental results demonstrate the successful transmission and display of thermal pixel data between the ESP8266 microcontrollers using the UDP protocol. The project utilizes the Arduino framework along with ESP8266WiFi and UDP libraries to enable network connectivity and UDP communication. The sender and receiver devices are connected to the same local network, guaranteeing efficient and low-latency transmission of thermal pixel data. The system achieves real-time communication within a radius of approximately 15–18 m, ensuring immediate visualization of thermal images on connected displays. By minimizing latency, the system enables a seamless and instantaneous viewing experience offering seamless and instantaneous image visualization for the users.

Experimental investigation for multi-defect detection of industrial pipeline based on passive infrared thermal imaging analysis: A case study

Corrosion of pipe walls is a major hidden hazard for the safety of chemical enterprises; therefore, detection of the depth of pipe wall corrosion defects is extremely important. In this study, passive thermal imaging technology was used to detect and evaluate corrosion defects of different shapes in pipe walls and of different depths for the same shape. Three-dimensional finite element models of defects with different depths were established using COMSOL, and the thermal response mechanisms of defects with different depths and the effects of defect depth and shape on heat transfer were analyzed. The thermal response mechanism of defects with different shapes and depths (1–3 mm) was also analyzed experimentally and compared with that of defect-free parts to analyze the safety of the pipeline and verify the results of the numerical simulation analysis. The results indicated that the level of fluid temperature determined the accuracy of the test, and at the same temperature, the defects at a depth of 3 mm exhibited multiple peaks and a large peak area. However, defects with a depth of 2 mm exhibited the opposite behavior, and the heating rate of 3-mm deep defects during the temperature change was 1.08 times higher than that for 2 mm-deep defects. This study provides a reference for detecting leaks in chemical pipelines.

Quantum agriculture and experimental detection of wheat flour quality using thermal image technology

Crop quality and productivity are the fundamental strategies of agricultural practice and technology; consequently, one of the priorities in agriculture is to be aware of new and innovative field experiments and production practices. The effectiveness of innovative practices and resources is influenced by a multitude of factors. This study aimed to propose a new quantum-based approach in agriculture using homoeopathic methodology which incorporates theories and concepts of quantum physics and employs a wave-based methodology for the functional measurement phase. A novel utilization of thermal imaging technology is suggested, wherein each pixel of the image indicates the wave parameters, frequency, or amplitude of wave, is proposed to analyse the functional information of the plant. The relationship between the new quantum-agriculture-based method and the functional characteristics of flour as measured by bio-photonic emissions was estimated, and the findings of this preliminary study on wheat flour are presented. Our preliminary results (i) confirm the superior performance of quantum agriculture (QA) based proposed soil and plant treatments, and (ii) suggest that quantitative analysis based on precise measurements of biophoton emission will provide a novel reliable tool for monitoring the quality of wheat in the future. Further investigations are required to replicate the results of this study under different environmental conditions. Additionally, incorporating comparative chemical analyses that would enhance our knowledge of the proposed agronomic practice.

Uses of Smartphone Thermal Imaging in Perforator Flaps as a Versatile Intraoperative Tool: The Microsurgeon's Third Eye

IntroductionIn this study, we evaluate the versatility of smartphone thermal imaging technology as a valuable intraoperative modality in different stages of perforator flap surgery aiming to minimize the complications and achieve the best postoperative outcome. Patients and methodsThermography was performed in 20 perforator flaps in 20 patients at different surgical stages in three different ways to identify the most dominant perforator: first, by measuring the surface temperature of the skin; second, by using the dynamic infrared thermography technique; and third, by assessing the perfusion pattern when the flap was supplied by each perforator separately. Thermography was used to help in discarding the least perfused area of the flap. After microvascular anastomosis, the flap reheating pattern was evaluated. ResultsSeventeen free and three pedicled perforator flaps were included. Intraoperatively, each of the selected perforators had a corresponding hotspot. The perforator with the hottest hotpot, best rewarming, and provision of best flap perfusion on thermography was found clinically dominant. After microvascular anastomosis in free flaps, rapid rewarming was recorded in 15 cases. In two deep inferior epigastric perforator flaps, no rapid rewarming was observed. The pedicle was kinked in one case and there was a venous insufficiency in another case that required a cephalic turndown. All flaps showed good perfusion on thermography after inset. ConclusionSmartphone thermography has proven to be a valuable, cheap, rapidly employed, and objective tool not only for the design of perforator flaps, but also for the decision making intraoperatively to achieve the best surgical outcome.

Study on a method for suppressing influence of nonuniform surface emissivity of material in eddy current thermography

The nonuniform emissivity of material surface will adversely affect the detection results of the thermal imaging technology. Aiming at the influence of uneven emissivity on the dynamic detection mode of eddy current thermography, a suppression method based on edge detection is proposed in this paper. Since the traditional threshold selection methods are not ideal, a local adaptive threshold selection (LATS) method is applied in this study. This method can automatically obtain the optimal threshold for edge detection to suppress the influence of uneven emissivity. Roberts, Sobel, Prewitt, and Canny operators are tested by using LATS. The results show that Roberts, Sobel, and Prewitt operators can achieve the suppression effect, but the effect of Sobel and Prewitt are similar and better than Roberts.

RESEARCH ON DETERIORATION DIAGNOSIS SYSTEM FOR BUILDING EXTERIOR WALL USING BUILDING INFORMATION MODELING

The exterior walls of buildings in Taiwan often use tiles as external wall materials. When the deterioration occurs behind the tile, it is not easy to judge the problem from the surface. Infrared thermal imaging technology is a non-destructive testing, which can quickly and widely confirm the damage of the external wall tiles of the whole building, so it is often used in the deterioration diagnosis for old buildings. In this study, the risk levels were classified as A, B, and C from the information of thermal image temperature differences (2.01℃, 2.25℃, 2.65℃) experiment. If the temperature difference is greater than 5°C, the degradation grade is C2, and the hollowing rate behind the tile is 75%. First floor on the east side of the chemical hall, the actual building in National Taipei University of Technology, was taken as the research object. Build a Revit building information model, input basic building information, upload thermal images and actual photos, and judge the degree of building deterioration. There are 7 pieces in C1 level, accounting for 0.29%, 2 pieces in C2 level, accounting for 0.08%. The results will be visualized with a building information model for deteriorating exterior walls to provide university effective maintenance information.

Experimental study on damage law of liquid CO2 cyclic freeze–thaw coal

In order to study the damage characteristics of coal under liquid CO2 (LCO2) cyclic freeze-thaw (F-T), ultrasonic detector and infrared thermal imaging technology were used to discuss the ultrasonic wave propagation of coal and the surface temperature evolution law of coal samples during LCO2 cyclic F-T. The nuclear magnetic resonance technology was used to study the pore structure evolution of coal body. The results show that the velocity of primary wave and secondary wave is reduced. The more cycles, the lower the minimum temperature of coal side and end face. The temperature difference at different points on the same measuring line is large, indicates that the heterogeneity of coal sample under the same temperature causes anisotropy of heat transfer inside the matrix. The pore structure changes greatly under the LCO2 cyclic F–T action. With the increase of the number of cycles, the proportion of adsorption pores decreased, the proportion of seepage pores increased, and the pore volume increased，the total porosity and effective porosity showed an exponential upward trend, the bound porosity showed an exponential downward trend, indicating that LCO2 cyclic F–T is conducive to the increase of crack volume and the improvement of crack connectivity.

Heat diffusion optimization in high performance perovskite solar cells integrated with zeolite

Heat accumulation inside perovskite solar cells causes the decomposition of the perovskite layer and hole transport materials (HTMs) under working conditions, yielding a decrease in long-term stability. Here, we present a zeolite-assisted heat conduction strategy by introducing economic zeolite crystals (e.g., NaX, NaY, and ZSM-5) as a cooling filter to induce heat diffusion. The fitted thermal diffusion kinetic equation from real-time infrared thermal imaging technology reveals the zeolite skeleton assisted thermal conduction mechanism of internal lattice vibration. Additionally, the nearly twofold improved conductivity of the modified HTM film is benefited from Na+ hopping on the supercages of the zeolite, therefore, the best-performed device with a rapid heat diffusion and defect inhibition obtains a remarkable power conversion efficiency of 23.42%. Both of NaX modified sprio-OMeTAD and PTAA based devices exhibit excellent operational stability after heating 1000 h at 85 °C under N2 condition. This work demonstrates the potential application of economical porous zeolite materials in improving the thermal stability of PSCs.

Thermal aerial culling for the control of vertebrate pest populations

Helicopter-based shooting is an effective management tool for large vertebrate pest animals. However, animals in low-density populations and/or dense habitat can be difficult to locate visually. Thermal-imaging technology can increase detections in these conditions. We used thermal-imaging equipment with a specific helicopter crew configuration to assist in aerial culling for feral pigs (Sus scrofa) and fallow deer (Dama dama) in South Australia in 2021. Seventy-two percent of pigs and 53% of deer were first detected in dense canopy/tall forest habitat. Median time from the first impact shot to incapacitation was < 12 s. The culling rate (animals hour−1) doubled compared to visual shoots over the same populations and the wounding rate was zero resulting in a incapacitation efficiency of 100%. The crew configuration gave the shooter a wide field of view and the thermal operator behind the shooter provided essential support to find new and escaping animals, and to confirm species identification and successful removal. The crew configuration allowed for successful target acquisition and tracking, with reduced target escape. The approach can increase the efficiency of aerial culling, has the potential to increase the success of programs where eradication is a viable option, and can improve animal welfare outcomes by reducing wounding rates and the escape of target animals.

Study on the infrared dynamic evolution characteristics of different joint inclination phyllite under uniaxial compression

The destructive behavior of rocks and the evolution behavior of cracks are highly correlated. With the continuous development process of crack, the stress state of rock is constantly broken until entirely failed, so it is necessary to study the spatial and temporal behavior characteristics of the crack in the process of rock destruction. In this paper, the destruction process of phyllite specimens is analyzed by thermal imaging technology, and the temperature evolution process of the crack is studied to explore the infrared characteristics of the crack evolution process. Furthermore, a model for predicting rock destruction time is proposed based on Bi-LSTM recurrent neural network model combined with Attention mechanism. The results show that: (1) During the development of rock cracks, the rock surface shows a stable dynamic infrared response, and shows different evolutionary characteristics in different stages, mainly including temperature reduction in the compaction stage, temperature rise in the elastic and plastic stages, and temperature peaks in the failure stage; (2) During the evolution of the crack, rock destruction has a significant control effect on the IRT field along the fracture tangential and normal direction, and its distribution has the volatility controlled by the time; (3) The recurrent neural network method is used to predict the rock failure time, the results can be used as a method to predict the time of rock destruction, and it can be further put forward the corresponding protective measures accordingly, to maintain the long-term stability of the rock mass.

Bioinspired Near-Full Transmittance MgF2 Window for Infrared Detection in Extremely Complex Environments

Due to the extreme complexity of the anti-reflective subwavelength structure (ASS) parameters and the drastic limitation of Gaussian beam manufacturing accuracy, it remains a great challenge to manufacture ASS with ultrahigh transmittance on the surface of infrared window materials (such as magnesium fluoride (MgF2)) directly by femtosecond laser. Here, a design, manufacturing, and characterization method that can produce an ultrahigh-performance infrared window by femtosecond laser Bessel beam is proposed. Inspired by the excellent anti-reflective and hydrophobic properties of the special structure of dragonfly wings, a similar structural pattern with grid-distributed truncated cones is designed and optimized for its corresponding parameters to achieve near-full transmittance. The desired submicron structures are successfully fabricated by a Bessel beam after effectively shaping the beam. As a practical application, the bioinspired ASS is manufactured on the surface of MgF2, achieving an ultrahigh transmittance of 99.896% in the broadband of 3–5 μm, ultrawide angle of incidence (over 70% at 75° incidence), and good hydrophobicity with a water contact angle of 99.805°. Results from infrared thermal imaging experiments show that the ultrahigh-transmittance MgF2 window has superior image acquisition and anti-interference performance (3.9–8.6% image contrast enhancement and more accurate image edge recognition) in an environment with multiple interfering factors, which may play a significant role in facilitating applications of infrared thermal imaging technologies in extremely complex environments.

A full-time deep learning-based alert approach for bridge–ship collision using visible spectrum and thermal infrared cameras

With the rapid development of transportation infrastructure and the growing water transportation industry, many bridges have been constructed across navigable rivers. However, collisions between ships and bridges remain a frequent occurrence, particularly under low illumination conditions. To address this issue, this paper proposes a full-time bridge–ship collision alert approach based on the combination of visible spectrum and infrared cameras. This approach includes the following steps: (1) capturing and identifying ships in the channel using a single visible spectrum camera is challenging in low illumination environments such as nighttime. To overcome this limitation, we propose the use of infrared thermal imaging technology, which can monitor ships at night due to their inherent emissivity of ship thermal radiation. By comprehensively analyzing factors such as the real-time lighting environment and comparing the advantages of visible spectrum cameras and thermal infrared cameras in object recognition under various illuminance levels, we determine the effectiveness of the decision-making method of the dual-channel camera for ships under different illumination conditions. (2) To detect and track ships in the channel, a deep learning-based automatic detection and tracking method is designed using visible spectrum and infrared thermal imaging cameras, providing early warning of dangerous trajectories of ships that threaten the piers. To address the real-time identification and positioning of ships by dual-channel cameras in different light environments, we adopt a target detection network and a displacement calculation algorithm for multi-target tracking. Analysis results demonstrate that this method can automatically assign visible spectrum and thermal imaging cameras as effective input sources in different illumination environments to detect and warn ships with dangerous trajectories, contributing to the safety of navigable ships and bridges in low illumination conditions.

Nondestructive Detection of Egg Freshness Based on Infrared Thermal Imaging

In this paper, we proposed a nondestructive detection method for egg freshness based on infrared thermal imaging technology. We studied the relationship between egg thermal infrared images (different shell colors and cleanliness levels) and egg freshness under heating conditions. Firstly, we established a finite element model of egg heat conduction to study the optimal heat excitation temperature and time. The relationship between the thermal infrared images of eggs after thermal excitation and egg freshness was further studied. Eight values of the center coordinates and radius of the egg circular edge as well as the long axis, short axis, and eccentric angle of the egg air cell were used as the characteristic parameters for egg freshness detection. After that, four egg freshness detection models, including decision tree, naive Bayes, k-nearest neighbors, and random forest, were constructed, with detection accuracies of 81.82%, 86.03%, 87.16%, and 92.32%, respectively. Finally, we introduced SegNet neural network image segmentation technology to segment the egg thermal infrared images. The SVM egg freshness detection model was established based on the eigenvalues extracted after segmentation. The test results showed that the accuracy of SegNet image segmentation was 98.87%, and the accuracy of egg freshness detection was 94.52%. The results also showed that infrared thermography combined with deep learning algorithms could detect egg freshness with an accuracy of over 94%, providing a new method and technical basis for online detection of egg freshness on industrial assembly lines.

Energy and Infrared Radiation Characteristics of the Sandstone Damage Evolution Process.

The mechanical characteristics and mechanisms of rock failure involve complex rock mass mechanics problems involving parameters such as energy concentration, storage, dissipation, and release. Therefore, it is important to select appropriate monitoring technologies to carry out relevant research. Fortunately, infrared thermal imaging monitoring technology has obvious advantages in the experimental study of rock failure processes and energy dissipation and release characteristics under load damage. Therefore, it is necessary to establish the theoretical relationship between the strain energy and infrared radiation information of sandstone and to reveal its fracture energy dissipation and disaster mechanism. In this study, an MTS electro-hydraulic servo press was used to carry out uniaxial loading experiments on sandstone. The characteristics of dissipated energy, elastic energy, and infrared radiation during the damage process of sandstone were studied using infrared thermal imaging technology. The results show that (1) the transition of sandstone loading from one stable state to another occurs in the form of an abrupt change. This sudden change is characterized by the simultaneous occurrence of elastic energy release, dissipative energy surging, and infrared radiation count (IRC) surging, and it has the characteristics of a short duration and large amplitude variation. (2) With the increase in the elastic energy variation, the surge in the IRC of sandstone samples presents three different development stages, namely fluctuation (stage Ⅰ), steady rise (stage Ⅱ), and rapid rise (stage Ⅲ). (3) The more obvious the surge in the IRC, the greater the degree of local damage of the sandstone and the greater the range of the corresponding elastic energy change (or dissipation energy change). (4) A method of sandstone microcrack location and propagation pattern recognition based on infrared thermal imaging technology is proposed. This method can dynamically generate the distribution nephograph of tension-shear microcracks of the bearing rock and accurately evaluate the real-time process of rock damage evolution. Finally, this study can provide a theoretical basis for rock stability, safety monitoring, and early warning.

Thermo‐based fatigue life prediction: A review

AbstractThe main objective of this review paper is twofold: Recall the most captivating areas of research in predicting the fatigue life of metals with the application of thermal methodology, particularly for the stress‐controlled fatigue tests. The explicit lifetime models reviewed have been developed by scholars over the past two decades owing to the advancements in infrared thermal imaging technology. Introduce, discuss, and conclude a broad range of alternative theoretical frameworks in thermodynamics. Some investigations are made with the previous methods, including the most recent evolutions of lifetime models for structural integrity across various fields. Some future perspectives are provided in final, which could pave the way for a new realistic or potential capability.