This PDF file contains the front matter associated with SPIE Proceedings Volume 8013, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Target temperature estimation from thermal infrared (TIR) imagery is a complex task that becomes increasingly more difficult as the target size approaches the size of a projected pixel. At that point the assumption of pixel homogeneity is invalid as the radiance value recorded at the sensor is the result of energy contributions from the target material and any other background material that falls within a pixel boundary. More often than not, thermal infrared pixels are heterogeneous and therefore subpixel temperature extraction becomes an important capability. Typical subpixel estimation approaches make use of data from multispectral or hyperspectral sensors. These technologies are expensive and data collected by a multispectral or hyperspectral thermal imagery might not be readily available for a target of interest. A methodology has been developed to retrieve the temperature of an object that is smaller than a projected pixel of a single-band TIR image using physics-based modeling. The process can be broken into two distinct pieces. In the first part, the Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool will be used to replicate a collected TIR image based on parameter estimates from the collected image. This is done many times to build a multi-dimensional lookup table (LUT). For the second part, a regression model is built from the data in the LUT and is used to perform the temperature retrieval. The results presented are from synthetic imagery.

In a context of quantitative thermography, the major problem in determining the true temperature of an object is the knowledge of its emissivity. This problem is very complicated, above all when its value changes during the measurement. This article deals with a new radiative method for measuring true temperature fields with an on-line determination of emissivity. This method, called thermoreflectometry, consists in the indirect emissivity measurement by a reflectometry method in addition to the radiance temperature measurement. It assumes that the shapes of bidirectional reflectivity distribution is homothetic for two wavelengths. This assumption is much less restrictive than the gray body one (emissivity equal for two wavelengths). Finally, those two measurements and the assumption are fused for determining the true temperature field and the diffusion factor field, a key parameter of the method. This parameter provides information on the surface properties (diffuse or specular) ans it is assumed to be independent of the wavelength. The theoretical basis of thermoreflectometry method are explained and a precise description of the apparatus is given. Measurements on instrumented samples, heated at a temperature of 350°C and with non uniform emissivity, are in broad agreement with the theory and show a high accuracy of the method, in reference to thermocouples measurements. The main assumption of the method is also verified by additional measurements of the bidirectional reflectivity distribution function (BRDF). These results demonstrate the relevance of this method, based on a simple embedded sensor, for measuring the true temperature field on samples with non-uniform and unknown emissivity.

The focus of this study is two-fold: first, to investigate the feasibility of thermal imaging for characterizing the development of chicken embryos; and second, to compare the effects of photo periods of 11 hours of light followed by 11 hours of darkness (11-11) versus 24 hours of darkness (24 dark) during the incubation cycle on embryo development. Previous reported work has used invasive methods, such as ultrasound, tomography, and MRI to study chicken embryos with some success. However, very little work has been reported on use of thermography, which is a non-invasive method. Results suggest that use of a cooling-heating-cooling cycle can reveal the anatomy of chicken embryos. A statistical comparison of image data from the two photo periods found no difference in the average cooling rates. However, the 11-11 group of eggs did hatch earlier overall than 24-dark group. Of the hatched eggs, all the chickens from the 24-dark group appeared to be in normal physical condition. However, two of the chickens from the 11-11 group appeared to have leg weakness shortly after hatching. Of these, one fully recovered the next day and the second remains the same after two days of observation. In addition, the second chicken took about 48 hours to fully emerge from its shell.

Boron Neutron Capture Therapy (BNCT) is a treatment modality, currently focused on the treatment of cancer, which involves a tumor selective ¹⁰B compound and a specially tuned neutron beam to produce a lethal nuclear reaction. BNCT kills target cells with microscopic selectivity while sparing normal tissues from potentially lethal doses of radiation. In the context of the Argentine clinical and research BNCT projects at the National Atomic Energy Commission and in a strong collaboration with INVAP SE, we successfully implemented Dynamic Infrared Imaging (DIRI) in the clinical setting for the observation of cutaneous melanoma patients and included DIRI as a non invasive methodology in several research protocols involving small animals. We were able to characterize melanoma lesions in terms of temperature and temperature rate-of-recovery after applying a mild cold thermal stress, distinguishing melanoma from other skin pigmented lesions. We observed a spatial and temporal correlation between skin acute reactions after irradiation, the temperature pattern and the dose distribution. We studied temperature distribution as a function of tumor growth in mouse xenografts, observing a significant correlation between tumor temperature and drug uptake; we investigated temperature evolution in the limbs of Wistar rats for a protocol of induced rheumatoid arthritis (RA), DIRI being especially sensitive to RA induction even before the development of clinical signs and studied surface characteristics of tumors, precancerous and normal tissues in a model of oral cancer in the hamster cheek pouch.

While an enormous amount of infrared techniques have been developed in the past, recent new testing protocols combining aerial infrared surveys, with handheld infrared measurements along with blower door testing, and computational analyses of the optimal solutions to increase building efficiency have provided some surprising results. These new product testing protocols and the results now point the way to suggested changes in the construction of big box buildings, the weatherization of existing commercial buildings, and a methodology for prioritizing optimal solutions based upon the net present value of any efforts for improvement relative to projected energy costs.

The improvement of energy efficiency is the key issue after the energy performance of buildings directive came into the force in European Union countries. The city of Kuopio participate a project, in which different tools will be used, generated and tested to improve the energy efficiency of public buildings. In this project there are 2 schools, the other consuming much more heating energy than the other same type of school. In this paper the results of the thermography in normal conditions and under 50 Pa pressure drop will be presented; as well as the results of remote controlled air tightness test of the buildings. Thermography combined with air tightness test showed clearly the reasons of specific consumption differences of heating energy - also in the other hand, the measurements showed the problems in the performance of ventilation system. Thermography, air tightness test and other supporting measurements can be used together to solve energy loss problems - if these measurements will be carried out by proper way.

The question of how to map the 3D indoor temperature by infrared thermography is solved by a hybrid method which is a combination of infrared thermography and the well known heat diffusion equation. The idea is to use infrared thermography to get the surface temperature of each frontier of the 3D domain of interest. A suitable procedure is devoted to this, allowing an automatic scanning of the whole frontier, the registration of data and computation. These surface temperatures constitute the boundary conditions of the heat equation solved in the domain of interest. The solution of the heat equation allows analyzing and controlling the temperature of every point belonging to the considered domain. This temperature distribution is controlled over the time with a period of the same order than the necessary time to obtain the frontier temperatures and at the end to contribute to the analysis of the thermal comfort. The study is done for the steady-state conditions under various weather situations. In this case the temperature depends only on space coordinates. With such procedure, we can have an idea about the time necessary to reach thermal equilibrium; time which has a great impact on the thermal comfort sensation. The results yielded by this method are compared with those given by others techniques used for temperature measurement. Finally, the method is used to access 3D temperature distribution for various geometric shapes.

Fixed gas detection equipment for the petroleum industries is no ordinary equipment. It is designed for continued unattended surveillance in harsh environments. The equipment must be reliable and require limited field maintenance. An additional requirement is a high resistance to false alarms and interferences, which can potentially reduce the detector's efficacy and the level of protection provided. In recent years, several manufactures of IR imaging devices have launched commercial models that are applicable to a wide range of chemical species and suitable for industrial use. These cameras are rugged and sufficiently sensitive to detect low concentrations of combustible and toxic gases. Nonetheless, as users become acquainted with these imaging systems, questions of resilience to solar and flame radiation and other IR sources, interferences by fog or steam, have begun to emerge. These questions, in fact, reflect similar concerns as those raised with open path IR gas detectors when they first appeared in the market over 20 years ago. This paper examines an IR gas imager's performance when exposed to several false alarm sources. Gas detection sensitivity in the presence of false stimuli and response and recovery times under an uncontrolled outdoor environment were measured. The results show the specific model tested is reasonably immune to false alarms, while response times were unaffected by the presence of these sources.

Development of an early gas leak detection system is essential for safety of energy storage tank fields or chemical plants. Contact-type conventional gas sensors are not suitable for remote surveillance of gas leakage in wide area. Infrared camera has been utilized for gas leak detection, however it is limited only for detecting particular gas. In this study a gas leak identification system, which enables us to detect gas leakage and to identify gas type and density, is developed based on infrared spectrum imaging system utilizing low cost and compact microbolometer infrared camera. Feasibility of the proposed system was demonstrated by experimental results on identification of hydrofluorocarbon gas.

Standoff detection of gas leakage is a fundamental need in petrochemical and power industries. The passive gas imaging system using thermal imager has been proven to be efficient to visualize leaking gas which is not visible to the naked eye. The detection probability of gas leakage is the basis for designing a gas imaging system. Supposing the performance parameters of the thermal imager are known, the detectivity based on electromagnetic radiation transfer model to image gas leakage is analyzed. This model takes into consideration a physical analysis of the gas plume spread in the atmosphere-the interaction processes between the gas and its surrounding environment, the temperature of the gas and the background, the background surface emissivity, and also gas concentration, etc. Under a certain environmental conditions, through calculating the radiation reaching to the detector from the camera's optical field of view, we obtain an entity "Gas Equivalent Blackbody Temperature Difference (GEBTD)" which is the radiation difference between the on-plume and off-plume regions. Comparing the GEBTD with the Noise Equivalent Temperature Difference (NETD) of the thermal imager, we can know whether the system can image the gas leakage. At last, an example of detecting CO₂ gas by JADE MWIR thermal imager with a narrow band-pass filter is presented.

IR thermography is applied to detect hidden corrosion on carbon steel pipelines for oil transportation. The research is oriented to set up a robust technique to carry out in situ the early detection of corroded zones that may evolve either towards leakage or failure. The use of thermography associated with a transient thermal technique is investigated on 12.2 mm thick samples, machined to artificially create a reduction of wall thickness that simulates the effect of real corrosion in pipes. The extension and depth of the artificial defects is controlled by ultrasounds which represents the reference for the results obtained by thermography. Two approaches are proposed: the first is based on the processing of a single thermogram taken at the optimum time after a finite pulse heating of a large area of the external surface; the second technique is carried out by scanning the pipeline by means of a device composed of a linear lamp and a thermographic camera which move jointly over the surface to test. A suitable reconstruction provides a map of the tested surface with possible hot spots in correspondence with the corroded areas. The analysis of the thermal problem by Finite Element Method is used to optimize the experimental parameters. The experimental results demonstrate a detection capability starting from 15 % of wall thickness reduction.

Solder joint defects are a major variable in the failure of many printed circuit boards in the electronics industry. These defects are often missed, because they are hidden underneath layers of the printed circuit boards. In this study, we utilized a heat source and infrared camera to construct an experiment that tests the visibility of solder joints of different geometries with and without a cover. The objective of this work was to (1) understand the effects of different amounts of energy on soldering metal and the printed circuit board; (2) use Active Thermography and Pulse Thermography for the inspection of three solders of three different geometries: 60°, 90°, and 120°; (3) create plots depicting the relationship between the average cooling rate for each solder geometry and time per data set collected. Task objectives include: (1) construction of a fully automated heating and imaging chamber along with written PLC program; (2) create hypotheses and conduct experiments; (3) capture and analyze infrared images of each printed circuit board; (4) create models and evaluate data. Results present that (1) Active and Pulse Thermography can be used to visibly see solders of different geometries without a cover; (2) Average cooling rates plotted over time are a good indicator of calculating prediction rates between the solders; (3) as the difference in cooling rates increases, the better the prediction rates; (4) Active Thermography performed better than Pulse with a prediction rate of 84.3% as opposed to 61.9% without a cover.

Over the last 10 years, very large government, military, and commercial computer and data center operators have spent millions of dollars trying to optimally cool data centers as each rack has begun to consume as much as 10 times more power than just a few years ago. In fact, the maximum amount of data computation in a computer center is becoming limited by the amount of available power, space and cooling capacity at some data centers. Tens of millions of dollars and megawatts of power are being annually spent to keep data centers cool. The cooling and air flows dynamically change away from any predicted 3-D computational fluid dynamic modeling during construction and as time goes by, and the efficiency and effectiveness of the actual cooling rapidly departs even farther from predicted models. By using 3-D infrared (IR) thermal mapping and other techniques to calibrate and refine the computational fluid dynamic modeling and make appropriate corrections and repairs, the required power for data centers can be dramatically reduced which reduces costs and also improves reliability.

The low energy efficiency of conventional light sources is mainly caused by generation of waste heat. We used infrared (IR) imaging in order to monitor the heating of both LED tube luminaires and ordinary T8 fluorescent tubes. The IR images showed clearly how the surface temperatures of the fluorescent tube ends quickly rose up to about +50...+70°C, whereas the highest surface temperatures seen on the LED tubes were only about +30...+40°C. The IR images demonstrated how the heat produced by the individual LED chips can be efficiently guided to the supporting structure in order to keep the LED emitters cool and hence maintain efficient operation. The consumed electrical power and produced illuminance were also recorded during 24 hour measurements. In order to assess the total luminous efficacy of the luminaires, separate luminous flux measurements were made in a large integrating sphere. The currently available LED tubes showed efficacies of up to 88 lm/W, whereas a standard "cool white" T8 fluorescent tube produced ca. 75 lm/W. Both lamp types gave ca. 110 - 130 lx right below the ceiling-mounted luminaire, but the LED tubes consume only 40 - 55% of the electric power compared to fluorescent tubes.

Infrared thermography could be an important diagnostic tool for assessing the performance of photovoltaic panels. Malfunctions, material and insulation defects can be detected easily and fast without complicated proceedings. It can be applied to large and small scale systems so as to secure the best possible function and thus performance of the panel(s). In this work, a thermographic survey was performed on a photovoltaic plant of 1 MW in Greece. Various deficiencies were detected by using in situ thermography. Although these panels were only a few months into use, there were defected areas spotted by thermography, indicating the poor performance of these panels and thus affecting the total power output of the photovoltaic plant.

Infrared active-source lock-in techniques are used for a variety of solar cell inspections, including electro- and photoluminescence, carrier density imaging, shunt imaging and physical defects. The principles and power of the lock-in technique are reviewed for these inspection methods. Different camera types, including NIR, MW and LW, are available for the different techniques. A selection of excitation sources--electrical, laser, lamp and mechanical-stimulate different physical phenomena. Measurements are presented of several manufacturing yield limiting parameters, and the advantages and limitations of the techniques are discussed.

Several sensors are used during the performance tests of a turbojet engine to record parameters such as temperature, pressure, vibration, etc. However, most of these sensors have long time constants and are unable to measure fast transients and fluctuations. In this paper we show an alternative sensor to characterize some phenomena observing the flow resulting from the combustion at the outlet of a turbojet engine, using a very high-speed uncooled MWIR COTS imaging sensor from New Infrared Technologies, which provides over 1,600 fps. The experiments include monitoring of flow stability during a long observation time (accelerations and stationary regimes), and higher frequency events such as surges. Compressor surges produce extremely loud bangs from the engine, and may be accompanied by a fast increment of the exhaust gas temperature and an increase in rotor speed due to the reduction in work done by the stalled compressor, causing severe stresses within the engine from the intense aerodynamic buffeting within the compressor. The main conclusion of this study is the demonstration of the potential and worthiness of high-speed uncooled IR imagers for detecting and analyzing fast transient events and stationary events during combustion test studies from thrusters such as turbojets and rockets.

In recent years Brazil has experienced extraordinary growth despite the recent economic global crisis. The demand for infrared thermography products and services has accompanied this growth. Like other non-destructive testing and inspection, the results obtained by thermography are highly dependent on the skills of thermographer. Therefore, it is very important to establish a serious and recognized process of certification to assess thermographers' qualifications and help services suppliers to establish credibility with their customers and increase the confidence of these costumers on the quality of these services. The Brazilian Society of Non-Destructive Testing and Inspection, ABENDI, a non-profitable, private technical-scientific entity, recognized nationally and internationally, has observed the necessity of starting a process for certification of thermographers in Brazil. With support of a work group composed by experts from oil and energy industries, transportation, universities and manufactures, the activities started in 2005. This paper describes the economic background required for installation of the certification process, its initial steps, the main characteristics of the Brazilian certification and the expectation for initiating the certification process.

Active infrared nondestructive evaluation (AIRNDE) involves mapping of surface temperatures over the test object, for a known imposed incident heat flux, to detect surface and subsurface defects (voids, disbands, cracks etc.). It is a fast, whole field and remote inspection method for defect detection. Since most of the solids conduct heat, AIRNDE has the potential for wide use in non destructive testing of variety of solid materials. It is achieved by observing, recording and analyzing the thermal response over the material surface to a heat stimulus and is broadly known as active thermography in contrast to passive thermography where no heat stimulus is applied. This paper highlights the defect detection capabilities of digitized frequency modulated thermal wave imaging for carbon and glass fiber reinforced plastic materials.

Detecting defects, and especially reliably measuring defect sizes, are critical objectives in automatic NDT defect detection applications. In this work, the Sentence software is proposed for the analysis of pulsed thermography and near IR images of composite materials. Furthermore, the Sentence software delivers an end-to-end, user friendly platform for engineers to perform complete manual inspections, as well as tools that allow senior engineers to develop inspection templates and profiles, reducing the requisite thermographic skill level of the operating engineer. Finally, the Sentence software can also offer complete independence of operator decisions by the fully automated "Beep on Defect" detection functionality. The end-to-end automatic inspection system includes sub-systems for defining a panel profile, generating an inspection plan, controlling a robot-arm and capturing thermographic images to detect defects. A statistical model has been built to analyze the entire image, evaluate grey-scale ranges, import sentencing criteria and automatically detect impact damage defects. A full width half maximum algorithm has been used to quantify the flaw sizes. The identified defects are imported into the sentencing engine which then sentences (automatically compares analysis results against acceptance criteria) the inspection by comparing the most significant defect or group of defects against the inspection standards.

Principal Component Analysis (PCA) has been shown effective for reducing thermographic NDE data. This paper will discuss an alternative method of analysis that has been developed where a predetermined set of eigenvectors is used to process the thermal data from both reinforced carbon-carbon (RCC) and graphite-epoxy honeycomb materials. These eigenvectors can be generated either from an analytic model of the thermal response of the material system under examination, or from a large set of experimental data. This paper provides the details of the analytic model, an overview of the PCA process, as well as a quantitative signal-to-noise comparison of the results of performing both conventional PCA and fixed eigenvector analysis on thermographic data from two specimens, one Reinforced Carbon-Carbon with flat bottom holes and the second a sandwich construction with graphite-epoxy face sheets and aluminum honeycomb core.

Flaw detection and characterization with thermographic techniques in graphite polymer composites is often limited by localized variations in the thermographic response. Variations in properties such as acceptable porosity, variations in fiber volume content and surface polymer thickness result in variations in the thermal response that in general cause significant variations in the initial thermal response. These variations result in a noise floor that increases the difficulty of detecting and characterizing deeper flaws. The paper investigates comparing thermographic responses taken before and after a change in state in a composite to improve the detection of subsurface flaws. A method is presented for registration of the responses before finding the difference. A significant improvement in the detectability is achieved by comparing the differences in response. Examples of changes in state due to application of a load and impact are presented.

Pulsed thermography produces temperature rise images depending on the space variability of the optical properties of the tested sample and of the fluence of the stimulating heat flux. It is demonstrated that a simple and efficient normalization of the thermograms is possible and constitutes a drastic remedy to this weakness. This is illustrated by applications to realistic defects and configurations. The way to optimize the normalization and to define a sound reference needed for defect detection are also discussed and illustrated by the analysis of NDE experiments. After normalization, the amplitude based pulsed thermograms present strong advantages compared to phase-based thermograms, in particular their large pass-band allows the early detection/characterization of defects. The benefit of using the TSR technique is also shown, especially if used in conjunction with the early detection approach.

In thermography surveys, the inspector uses the camera to acquire images from the examined part. Common problems are the lack of repeatability when trying to repeat the scanning process, the need to carry the equipment during scanning, and long setting-up time. The aim of this paper is to present transient thermography results on CFRP plates for assessing different types of fabricated defects (impact damage, inclusions for delaminations, etc), as well as and to discuss and present a prototype robotic scanner to apply non destructive testing (thermographic scanning) on materials and structures. Currently, the scanning process is not automatic. The equipment to be developed, will be able to perform thermal NDT scanning on structures, create the appropriate scanning conditions (material thermal excitation), and ensure precision and tracking of scanning process. A thermographic camera that will be used for the image acquisition of the non destructive inspection, will be installed on a x, y, z, linear manipulator's end effector and would be surrounded by excitation sources (optical lamps), required for the application of transient thermography. In this work various CFRP samples of different shape, thickness and geometry were investigated using two different thermographic systems in order to compare and evaluate their effectiveness concerning the internal defect detectability under different testing conditions.

The infrared thermography has not been widely applied to nondestructive inspection for metals. It is because the metal emissivity is too low to be measured the temperature. To make up for this disadvantage, a new heating technique using a stainless steel film was proposed and a nondestructive inspection system with the response surface method was developed. The stainless film has a high electric resistance and generates large Joule heat. Its response is quick and the quantity of heat is easily controlled. Moreover, the film has a high enough thermal conductivity, therefore a black painted film can be a blackbody surface of metal structures. Consequently IR camera can easily measure the metal temperature accurately. The nondestructive inspection system that can quantitatively identify geometrical parameters of a local thinning was developed. The system consists of a forward analysis and an inverse analysis. In the forward analysis, the response surface that shows a relationship between geometrical parameters and characteristic values is built by experimental design method. In the inverse analysis, substituting the characteristic values into the response surface, the geometrical parameters are finally identified. The inspection system can identify the local thinning shape robustly by selecting the attribute for the shape parameters.

Active thermography can be well used to detect subsurface defects like buried cavities in materials. For metallic materials induction heating is the most efficient technique, because the heat is generated directly in the material and therefore the usually low emissivity and absorption coefficient of the metallic surface does not affect the heating process. Short inductive heating pulses (0.5-2 s) have been used to detect holes with a diameter of 2 mm in a depth of 2-4 mm below the surface in aluminum samples. Some of the defects were generated during the production process; other ones were created artificially. The size and the depth of these defects were determined with the help of computer tomography. Additionally to the experimental data, also finite element simulations and analytical calculations have been carried out in order to model the heat distribution for different defect sizes and defect depths. The calculations have been used to optimize the heating pulse duration. Based on the modelling results, an evaluation algorithm has been developed, which allows an automatically localization of the defects with help of image processing techniques. In order to test the stability of the automated evaluation, noise has been added to the calculated temperature distribution. The same processing technique has been used for the evaluation of the experimental data to localize subsurface defects and very good detection results could be achieved.

Bicycles, cars, airplanes, prosthetics, solar panels...composites are ubiquitous in the modern world. Three thermographic NDT techniques are currently in use for the detection and measurement of defects in these composites, including defects such as impact damage, delamination, voids, inclusions and stresses. The particular technique for optimum results, pulsed flash, pulsed transient, or lock-in, depends upon the sample material and thickness and shape, and the test environment. Choice of camera type varies widely, from high performance cooled to affordable uncooled, with large format 640 x 480 pixels now available, also. NDT hardware and software now includes models that allow all types of excitation sources and excitation methods with the same equipment.

Thermographic approaches, passive and active, are widely used due to the outstanding advantages that offer in a number of applications and particularly for the assessment of materials. Nonetheless, there are limitations; depending upon the approach used, as well as on the materials thermal, optical and physical properties, proper assessment (detection and/or quantification) is feasible. In thermal non-destructive evaluation (NDE), the active approach of infrared thermography where an excitation source, such as optical flash lamps, heat lamps, hot or cold air guns, etc., is employed with the intention of inducing thermal contrasts, has several applications. The temperature differences during the transient phase appear on the material surface and so detection of subsurface defects is possible (areas of different temperatures when compared to the sound part(s) due to the different thermal diffusivity). Since the heating or cooling features of the stimulus source are identifiable (in time and amplitude) by considering the time factor quantitative assessment is also feasible. However, when a material is heated, the thermal waves penetrate the material's surface. These waves are generally of various amplitudes and frequencies and are launched into the specimen, in a transient mode (i.e. transient thermography). In this work, different applications, employing transient thermographic testing, concerning the assessment of various composite materials and components are presented. Real time NDE is presented using various transient thermography approaches, i.e. pulsed thermography (PT), pulsed phase thermography (PPT) and/or thermal modelling (TM).

A recently developed technique is presented for thermographic detection of delaminations in composites by performing temperature measurements with fiber optic Bragg gratings. A single optical fiber with multiple Bragg gratings employed as surface temperature sensors was bonded to the surface of a composite with subsurface defects. The investigated structure was a 10-ply composite specimen with prefabricated delaminations of various sizes and depths. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The data obtained from grating sensors were analyzed with thermal modeling techniques of conventional thermography to reveal particular characteristics of the interested areas. Results were compared and found to be consistent with the calculations using numerical simulation techniques. Also discussed are methods including various heating sources and patterns, and their limitations for performing in-situ structural health monitoring.

Overlap shear splices are common in civil FRP strengthening applications when the overall length of a saturated ply becomes prohibitive or access to the surface being strengthened is restricted. The objective of this research was to develop a standard test method for evaluating overlap splices in wet lay-up FRP composite samples. Single-shear specimens were constructed from carbon fiber FRP with variable overlap splice lengths ranging from 1 in to 4 in. Each specimen was subjected to cyclic loading at a rate of 1 Hz and an IR camera was used to monitor the temperature variations resulting from the cyclic stress. A sinusoidal curve fit was applied to the temperature response for each pixel and the resulting amplitude image was used to evaluate the severity of stress concentrations at the ends of the overlap splice region as well as where the top ply of saturated composite formed a kink during lay-up.

Under certain conditions, the polarization state of infrared light emitted by metal changes when the metal is strained. During cutting, metal is severely strained. Assessing both strain and strain rate is of interest to the metal cutting research community. Over large areas, Digital Image Correlation (DIC) performed on high-speed video can provide approximate values for the average strain and strain rate. However, small areas such as the shear zone are difficult to image with enough resolution to perform DIC. If the thermal radiation emitted by these small areas is polarized, there is the potential to provide valuable information to the metal cutting community. This paper is an initial investigation into that possibility, as well as the use of the polarization information for uncertainty analysis, reflection detection, and region of interest classification. A rotating polarizer is used that triggers a thermal spectrum camera to acquire images at specific polarization angles. When cutting, the metal is constantly moving and the material imaged is different from one moment to the next. At each angle of the polarizer, a sufficiently long integration time is used so the material is severely motion blurred, resulting in an image which estimates the typical intensity for that angle. By comparing the typical intensities, and assuming the light is linearly polarized, the polarization state may be estimated.

We are developing two techniques for non-contact detection of explosives and other substances with low vapor pressure. In one approach, quantum cascade lasers (QCLs) at eye-safe power levels heat trace residues on surfaces at stand-off distances and the photo-thermal signal is imaged with an infrared camera. When using wavelengths corresponding to vibrational resonances specific to the trace molecules, the traces can be selectively heated and become visible in the infrared. In a second approach, a QCL or other IR laser of higher power is used to enhance the vapor signature of the analyte, thus facilitating vapor-based (e.g. ion mobility spectrometry) techniques. Details and advances in these techniques will be reported elsewhere. In this paper, we study the laser heating of analytes on substrates using the simulation software COMSOL. A model is validated with experimental results for particles of well characterized shape and size. The heat transfer between particle and substrate is of special interest, but not necessarily the dominant contributor to heat loss. Both air- and substrate-mediated heating of neighboring interferent particles is generally negligible. The presence of neighboring explosives particles affects the thermal kinetics via air-mediated heat transfer.

The applications of uncooled micro-bolometer VOx FPA to the micro-scale thermal analysis of polymeric & organic materials are presented. The latent heat during phase transition is analyzed with the emissivity correction calculation for all pixels that include the calibration algorithm using a real time direct impose signal system. It enables to visualize the exothermic latent heat of freezing biological cells at minus temperature. In comparison with the previously obtained data by using the InSb FPA sensor, the limitation and the possibility of the un-cooled micro-bolometer in view of application in thermal analysis of materials characterization are discussed.