Application Of Thermography Research Articles

Experimental investigation of animals survival adequacy and efficacy in case of their soft tissues gunshot wounds using the thermometry technique

The problem of gunshot wounds treatment is one of the urgent and incompletely resolved issues of modern surgery. Diagnosis of gunshot wounds is currently not efficient enough. There was a need to improve the content and scope of medical care with the possibility of strengthening its diagnostic chain. The aim of the work is to substantiate experimentally the feasibility and effectiveness of using diagnostic infrared thermometry in gunshot wounds of the soft tissues of the extremities. Experimental studies were performed under the chronic experimental conditions on Shinshilla breed rabbits which were subjected to gunshot wounds followed by laboratory, morphological and functional examination for 5 days. The animals were divided into 3 groups depending on the type of gunshot wound that was inflicted. The animals were removed from the experiment by the introduction of chloroethyl anesthesia on the 1st, 3rd and 5th days, after which the soft tissues with the capsule surrounding the fragment were subjected to histological and electron microscopic examination. On the 1st day of the study, a significant decrease in the diameter of the blood vessels of the affected area was determined in the group of animals that were subject to injury with firearms and metal fragments from the explosion of a grenade and an improvised explosive device. It was in these groups that the highest mortality rate was registered. Under the specified conditions of injury to the limbs of animals, as well as when injured by a pneumatic weapon with a temperature of fragments of 100 oC, pronounced changes in pulse and respiratory rate were noted. In further studies on rabbits on the 3rd and 5th days of the experiment, the actual results did not differ from those obtained 24 hrs after injury. Those rabbits that survived after the reproduction of various gunshot wounds had the greatest value. The results of their thermometric measurements were evaluated in the dynamics of experimental gunshot wounds and revealed the dependence of animal survival after gunshot wounds on the temperature of the limb in the area of the wound.
 There are the following leading criteria in favor of animals further survival after gunshot wounds - the presence of a perforating vessel in the area surrounding the affected space; the size of the diameter of the vessels in the adjacent area; no hemorrhage in the muscle tissue located near the affected area; comparable with normal data of the functional parameters of the animal's body – heart rate, blood oxygen pressure and respiration; thermometry results. The limb thermometry has the important prognostic value after their gunshot wound in terms of experimental animals survival. The correspondence of high thermometry indexes after a gunshot wound vs the higher risk of an animal death is statistically reliable and, accordingly, insignificant thermometric dynamics throughout the experiment is in favor of a positive outcome after injury. It is extremely important to evaluate thermometry data during the first 24 hours after receiving gunshot wounds, since we found out the maximum validity of this method in the early time intervals. All this, with adequate clinical testing and verification, has the most important medical prospects, aimed primarily at saving time for diagnostic measures and procedures. Thermometry allows to judge the activity and severity of connective tissue inflammation or sclerosis in the lesions of each wound and provides the possibility of clinical application of remote thermography as a non-invasive method of diagnosis and prediction of complications in wounded with gunshot and explosives in various wounds.

In situ Passive Infrared Thermography Application for the Assessment of Localized Mechanical Properties of Tungsten Inert Gas-Welded Inconel 625 Alloys

In situ Passive Infrared Thermography Application for the Assessment of Localized Mechanical Properties of Tungsten Inert Gas-Welded Inconel 625 Alloys

UAV-Based Photogrammetry and Infrared Thermography Applied to Rock Mass Survey for Geomechanical Purposes

A research study aimed at the extending the means of estimating ISRM (International Society for Rock Mechanics) geomechanical parameters through non-contact methodologies, in the frame of the remote survey of rock masses, is herein presented. It was conducted by coupling UAV-based photogrammetry and Infrared Thermography. Starting from georeferenced UAV surveys and the definition of rock masses’ RGB point clouds, different approaches for the extraction of discontinuity spatial data were herein compared according to the ISRM subjective and objective discontinuity sampling criteria. These were applied to a survey a window and along a scanline, both defined on the dense point clouds, to simulate a field rock mass survey, although carried out on remotely acquired data. Spatial discontinuity data were integrated via the analysis of dense point clouds built from IRT images, which represents a relatively new practice in remote sensing, and the processing of thermograms. Such procedures allowed the qualitative evaluation of the main geomechanical parameters of tested rock masses, such as aperture, persistence and weathering. Moreover, the novel parameters of Thermal-spacing (T-spacing) and Thermal-RQD (T-RQD) are herein introduced in a tentative attempt at extending the application field of IRT to remote rock mass surveys for practical purposes. The achieved results were validated by field campaign, demonstrating that a remote survey of rock masses can be conducted according to the ISRM procedures even on models built by integrating RGB and IRT photogrammetry. In fact, these two technologies are positively complementary and, besides being feasible, are characterized by a relatively quick and non-contact execution. Thanks to the positive and satisfactory results achieved herein, this research contributes to the implementation of the scientific and technical casuistry on the remote survey of rock masses, which is a technical field offering a wide range of applications.

Determining position of cracks on polished stone surfaces using flash active thermography

ABSTRACT This paper presents a novel application of active thermography for determining the positions of surface reaching cracks at polished stone slabs. The use of both a visual and a thermal camera, after calibration, allows us to overlap the results of the thermal analysis over visual images. A commercially available plate was used for calibration of cameras. The overlapping of the images enables us to plan more efficiently the cutting process, decreasing the waste and allowing us to choose the most desirable surface texture to become the part of the final product. The method allows us to reckon the direction of the crack inclination beneath the polished surface, based on the analysis of temperature distribution in proximity to the crack. A FEM analysis, which clarifies the temperature distribution in the surrounding of inclined crack, was presented.

Applicability of Thermography in Dentistry-Scoping Review

Introduction: Thermography offers a non-invasive radiation-free methodology for diagnostic imaging and temperature measurement, but the extent of the current application is unclear, as is the level of evidence for each use case. Moreover, population-based thermographic reference values for diagnostic purposes are nearly unknown. The present scoping review aims to assess the extent of literature and available evidence regarding the application of infrared thermography in dentistry to establish indications and further scope of its utility. Material and Methods: PubMed, Cochrane Database of Systematic Reviews and CENTRAL and Web of Science searches were done in July 2022 with specific keywords. Wide eligibility criteria were used to capture all relevant studies, published in English, and addressing thermal imaging in dentistry. The literature found was selected regarding the eligibility criteria. Relevant data was extracted from the included references into a collection chart in a synthesized narrative format and classified under the Levels of Evidence and Grades of Recommendation (Oxford Centre for Evidence-based Medicine, March 2009). Results: 13 studies were selected, 6 in vitro, 5 clinical trial and 1 case study and 1 systematic review. Four studies related the temperature variation of dental pieces with pulpal diagnosis. Three evaluated the effectiveness of thermography in the diagnosis of temporomandibular disorders. Five were used in surgery to measure inflammatory responses resulting from surgical procedures and temperatures reached when cutting hard tissues. One study evaluated, from an ergonomic point of view, the impact of bad working positions of oral health professionals. Conclusion: Within the limitations of this review, studies suggest that thermography has the potential to become an important tool in dental medicine, either as an auxiliary means of diagnosis in endodontics and temporomandibular disorders or as a complementary element in cutting procedures capable of producing heat with implications for the viability of the underlying structures. In addition, this scoping review can rouse new research foci regarding thermography.

Potential for the Application of Active Thermography in Estimation of Coating Thickness of a Polymer-Modified Cement-Waterproofing Material

Potential for the Application of Active Thermography in Estimation of Coating Thickness of a Polymer-Modified Cement-Waterproofing Material

Poboljšanje termofiziološkog komfora sportista na osnovu termografske procene materijala sportske odeće

Thermography is a widely used method of measuring surface temperature and its distribution. It is based on the measurement of the radiation intensity in the infrared region of the electromagnetic spectrum. Infrared thermography is applicable in all spheres of human activity because it broadens the world's view and irreversibly changes the notion of space that surrounds us. One of the important issues in professional sports is maintaining the optimal level of comfort during intense sports activities. Therefore, this paper aims to investigate the possibilities of the application of thermography for testing the properties related to the comfort of athletes focusing on the transfer of liquid (sweat) through the materials intended for making sportswear. Moreover, the accent is given to the comparison of non-aged materials, and materials aged applying different protocols characteristic for football sportswear.

Principles and cautions in the infrared thermography application in sheep

Infrared thermography is a safe technology for diagnostic imaging that preserves welfare and does not emit ionizing radiation. This paper aimed to report the principles of infrared thermography formation and cautions on imaging acquisition with sheep illustrations. This technique is based on capturing infrared electromagnetic energy from the matter molecules, proportional to the increase in temperature. The capture of images, not just in sheep, must obey technical criteria to avoid interpretation errors of the thermograms. Direct exposure to solar radiation, humidity, manipulation of the examined area, time of day, proper use of equipment, and the manifestation of certain behaviors can hinder the interpretation of the findings. Infrared thermography is a tool that helps practitioners because it provides practicality, safety, and accurate data.

Application of active thermography in study of the rotors dynamics

The article presents the infrared measurement techniques for analyzing and monitoring the dynamic state of the structure using advanced thermal imaging techniques. The article present an overview of the infrared measurement techniques and algorithms proposed research design based on the selected infrared measurement techniques. The article presents the results of a series of studies on the possibility of applying the vibrothermography methods in SHM systems. In particular it focuses on the analysis of the possibility of studying the dynamics of the rotor and the detection of its failures during operation. The results of vibrothermography studies of impeller made of plastic are presented. The results of studies based on algorithms developed by the authors. The article also presents the concept of the use of thermal imaging research in fault detection and monitoring of the dynamic state of real objects.

Thermographic Detection of Hidden Archaeological Features in a Cheshire Thatched Cottage, and Related Aspects of Thermal Performance: Case Study at Roadside Cottage

ABSTRACT Thermography can be an important tool for professionals working with traditional buildings. It is recognised by Historic England as providing information on a variety of structural features within buildings. Infrared thermography (IRT) is an acknowledged retrofit tool for reducing carbon emissions from traditional buildings. The paper explores the potential application of thermography as a tool for detecting infrared images emitted by the internal plaster surface of a timber-framed thatched cottage, dating from the 15th/16th century to 20th century. The thermal irregularities from hidden timber features or structural renovations under the thatch can help improve understanding of the evolution of the building and establish the extent of surviving historical fabrics. The images from IRT investigations conducted under different temperature difference conditions in 2010 and 2012 have been compared against the features exposed when re-thatching the property and upgrading insulation levels in 2019. A follow-up survey was carried out in 2021. Related aspects of the thermal performance of the thatched envelope and the effect on internal temperature distribution have also been investigated. The IRT investigations at Roadside Cottage demonstrated the importance of maintaining sufficiently large temperature differences across thatched roof buildings to permit detection of thermal irregularities arising from hidden timber features.

Application of liquid crystal thermography for temperature measurement of the absorber plate of solar air heater

Thermochromic liquid crystals (TLC) have indeed been utilized effectively in quasi heat transport and fluid dynamic research in recent years. Researchers in the areas of heat transfer and flow circulation have long used TLCs to map surface and spatial temperature changes. Before TLCs can be utilized for quantitative temperature measurements, they must first be calibrated to determine their color–temperature relationship. The goal of this article is to provide new and intermediate TLC users with an overview of the fundamentals and difficulties of TLC calibrations, with a focus on surface thermography. The first part of the article provides a comprehensive overview of thermochromic liquid crystals and the liquid crystal thermography technique. The final part of this paper concludes with a description of how liquid crystal thermography, both steady and transient, may be used to study heat transfer in turbulent flows. In the present article, Surface temperature TTLC is evaluated with the color response of TLC sheets and thermodynamic properties can be further calculated with the thermal relationship provided. The Imaging, colorimetry, lighting, and expected measurement error are all important elements of TLC calibration are discussed in this article.

Infrared thermography analysis with a low-cost camera in plaster sculptures of museum collections

Infrared thermography (IRT) is a non-destructive and non-invasive technique that provides the possibility to investigate the surface of sculptures for the detection of subsurface features and anomalies such as delamination, layer structure, fillings, and defects. IRT has been widely used in buildings and large structures, as well as in works of art such as bronze sculptures and paintings. This article describes the application of active infrared thermography, using a portable low-cost IRT camera, in the examination of plaster sculptures, a material where it has not yet been applied to. In particular, it was used in two plaster sculptures by 19th-century Portuguese artist Soares dos Reis, within a wider project (GEO-SR) aimed at the study of his work. The results indicate that thermography is a suitable technique with a great potential to detect alterations under the surface of plaster, revealing a new look into its manufacturing and conservation.

Estimating Thermal Material Properties Using Step-Heating Thermography Methods in a Solar Loading Thermography Setup

This work investigates solar loading thermography applications using active thermography algorithms. It is shown that active thermography methods, such as step-heating thermography, present good correlation with a solar loading setup. Solar loading thermography is an approach that has recently gained scientific attention and is advantageous because it is particularly easy to set up and can measure large-scale objects, as the sun is the primary heat source. This work also introduces the concept of using a pyranometer as a reference for the evaluation algorithms by providing a direct solar irradiance measurement. Furthermore, a recently introduced method of estimating thermal effusivity is evaluated on ambient-derived thermograms.

Application of non-invasive active infrared thermography for delamination detection in fresco

In the most common method of fresco painting, a unique integration of paint and plaster allows for frescos to acquire great durability and permanence. As the plaster or layers of fresco walls deteriorate over time, frescos become vulnerable to serious damage. In order to prevent such damage without harming frescos, non-destructive techniques must be used to analyze and determine areas of structure delamination. In the past, different non-destructive methods have been studied. However, many require expensive equipment. The main scope of this work is the evaluation of the effectiveness of non-invasive detection of fresco delamination via thermography, a comparatively inexpensive technique. In non-invasive active infrared thermography, thermal images are captured of a fresco before, during, and after a heating or cooling process. A defect beneath the surface acts as an insulative pocket, which in turn entraps heat and decreases the rate of heat diffusion. The accumulation of heat results in a defective region being abnormally hotter than a non-defective region, which causes a greater change in temperature throughout a heating or cooling process. Therefore, the analysis of the temperature change highlights defects location and entity beneath the surface. This technique was used and validated with two constructed surrogates, one with a known defect and one without a defect. The thermal analysis of the surrogates was performed via MATLAB®. Additionally, simulations of heating and cooling processes on modeled surrogates were generated in COMSOL® Multiphysics. The results of these simulations assessed the MATLAB® analysis and the use of non-invasive thermography as a tool to detect fresco delaminations. This method was then implemented on frescos within the Senate Reception Room of the United States Capitol Building.

Portable Generator to Detect Cracks on Large Steel Structures: An Application of Inductive Thermography

The demand of non-destructive methods to detect cracks caused by fatigue or brittle behavior in large steel structures has increased in the last years. Thermography based on electromagnetic induction is a promising method to detect cracks in weld seams and notches. This paper presents a portable experimental setup, which allows to perform in situ crack detection tests on large steel structures. The success of this configuration is based on the use of a highly efficient switched H-Bridge circuit, which can generate a square-wave output voltage with a fundamental frequency up to 100 kHz. Due to the low losses and the low necessary DC-link voltage, the circuit can be supplied by a lithium-ion battery, which allows a small and light setup. The generated square-wave output voltage supplies an air coil resulting in a high frequent triangle current. The induced electromagnetic field caused by the current signal generates eddy currents in the steel structure. Due to an increased current density of the eddy currents in the crack area, there is a measurable temperature increase near the crack. The resulting temperature field is visualized and recorded with an infrared (IR) camera, which shows in real time the occurrence of cracks.

Deep learning for defect characterization in composite laminates inspected by step-heating thermography

This paper presents a complete procedure for the non-destructive analysis of composite laminates, taking advantage of the step-heating infrared thermography and the latest developments of deep neural networks. One-dimensional temperature profiles of the target surface are collected in response to long heat pulses and individually feed a compact network made of convolutional filters, self-tuned to represent the signals in an equivalent feature space of improved discrimination. The resulting features are then classified to obtain the complete three-dimensional characterization of the properties of possible subsurface defects. Experimental validation is proposed to investigate a laminate of glass-fiber-reinforced polymer with several flat-bottom holes by changing the duration of the input heat pulses. This test produces surprisingly good results in the characterization of three classes of defects of increasing depth, including the most challenging at a depth of 6.38 mm, i.e. at the limit of applicability of the step-heating thermography. In the case of an excitation length of 180 s, the average balanced accuracy, precision, and recall are equal to 84.03%, 87.62%, and 82.43%, respectively. Moreover, a threshold operation on the classification scores further boosts the recall values of the class of the deepest defects from 53.87% to 82.41%. This enhancement of sensitivity suggests the applicability of the proposed procedure for the automatic inspection of composites structures in all application fields where safety is mandatory.

THERMOGRAPHY – A REVIEW

Thermography is a technique of measurement of skin temperature distribution on the body over a given period of time. It is a noncontact, noninvasive method that utilizes the heat from an object to detect, display, and record thermal patterns and temperature across the surface of the object. Over the years, various devices have been used to measure the amount of heat dissipated by the body and most recently thermography has been emerged to detect the oral and maxillofacial pathologies. It is used to detect malignancies of the maxillofacial region such as vitality of teeth, TMJ disorders, chronic orofacial pain, assessing inferior alveolar nerve decit, and detection of herpes labialis. The present article highlights the history, basic principles, types and applications of thermography and its benecial role in detecting the maxillofacial pathologies in dentistry.

Estimating Thermal Material Properties Using Solar Loading Lock-in Thermography

This work investigates the application of lock-in thermography approach for solar loading thermography applications. In conventional lock-in thermography, a specimen is subjected to a periodically changing heat flux. This heat flux usually enters the specimen in one of three ways: by a point source, a line source or an extended source (area source). Calculations based on area sources are particularly well suited to adapt to solar loading thermography, because most natural heat sources and heat sinks can be approximated to be homogenously extended over a certain region of interest. This is of particular interest because natural heat phenomena cover a large area, which makes this method suitable for measuring large-scale samples. This work investigates how the extended source approximation formulas for determining thermally thick and thermally thin material properties can be used in a naturally excited setup, shows possible error sources, and gives quantitative results for estimating thermal effusivity of a retaining wall structure. It shows that this method can be used on large-scale structures that are subject to natural outside heating phenomena.

Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application.

Unmanned Aerial Vehicles (UAVs) that can fly around an aircraft carrying several sensors, e.g., thermal and optical cameras, to inspect the parts of interest without removing them can have significant impact in reducing inspection time and cost. One of the main challenges in the UAV based active InfraRed Thermography (IRT) inspection is the UAV’s unexpected motions. Since active thermography is mainly concerned with the analysis of thermal sequences, unexpected motions can disturb the thermal profiling and cause data misinterpretation especially for providing an automated process pipeline of such inspections. Additionally, in the scenarios where post-analysis is intended to be applied by an inspector, the UAV’s unexpected motions can increase the risk of human error, data misinterpretation, and incorrect characterization of possible defects. Therefore, post-processing is required to minimize/eliminate such undesired motions using digital video stabilization techniques. There are number of video stabilization algorithms that are readily available; however, selecting the best suited one is also challenging. Therefore, this paper evaluates video stabilization algorithms to minimize/mitigate undesired UAV motion and proposes a simple method to find the best suited stabilization algorithm as a fundamental first step towards a fully operational UAV-IRT inspection system.

Spot size, distance and emissivity errors in field applications of infrared thermography

Abstract Infrared thermography is increasingly emerging as an analytical approach within the thermal ecology research community, providing unique and rapid temperature information crucial to understanding how plants and animals exchange heat with their environment. What is difficult to appreciate are the numerous ways in which thermography may still yield inaccurate (i.e. deviation from the ‘correct’ value) information if certain tenets are not followed. In this paper, we examine, demonstrate and discuss these tenets with an aim to provide methodological advice to ecologists interested in employing thermography. We found that spot size and distance strongly influenced the surface temperature estimates of known, calibrated temperature sources, with similar results observed in maximum eye temperature measurements in wild birds. We also report on how the angle of incidence affects the apparent emissivity of various biological surfaces (fur, feather, skin, leaves), another source of uncertainty in thermography. The variation in temperature caused by variation in distance and uncertainty in emissivity are large enough to raise flags for field applications of thermography where accuracy is necessary but control over study subjects is limited. Since accurate emissivity and distance parameters are crucial to thermography calculations, our results should serve as a framework to assist ecologists in better experimental design with respect to the use of thermography.