New transfer standard pyrometers, named "RT900" and "RT1550," operating at 900 nm and 1550 nm, respectively, have been designed, characterized, and calibrated with defined fixed points of the International Temperature Scale 1990 (ITS-90) at the National Institute of Standards and Technology (NIST). The pyrometers are designed for radiance temperature measurements in the range between the freezing temperatures of Sn (231.928 °C) and Ag (961.78 °C). These instruments also incorporate design elements optimized for compactness and portability that allow them to be used to interpolate, maintain and disseminate radiance temperature scales as well as for inter-laboratory comparisons. The calibration of the RT900 at different fixed points demonstrate agreement to within 25 mK. The size of source effect (SSE) correction for a source with a 40-mm diameter has been measured to be as low as 0.01 %.

Realization of a radiometric temperature scale for near ambient temperatures with accuracy at the 20 to 50 mK level is crucial for a number of demanding military and commercial applications. In support of such measurements, radiation sources with high stability and spatial uniformity must be developed as reference and working standards. Traditionally, the temperature scale, maintained at the National Institute of Standards and Technology (NIST), relies on water bath and oil bath blackbodies in this temperature range. Recently, a water heat pipe blackbody was used at NIST as a spectral radiance source in a spectral emissivity measurement facility. Now a new, more versatile high emissivity water heat pipe blackbody was designed and characterized to be used as a reference radiance source for the radiometric temperature scale realization between 50 °C and 250 °C. Furthermore, it will serve as a reference source for the infrared spectral radiance measurements between 2.5 μm and 20 μm. The calculated spectral emissivity of the painted copper alloy cavity was verified by reflectance measurements using a CO₂ laser at 10.6 μm wavelength. The spatial thermal uniformity and stability of the blackbody were characterized. Two independent realizations of the radiometric temperature scale were compared in order to verify the accuracy of the scale. Radiance temperature, calculated from the cavity temperature measured with a calibrated PRT contact thermometer and from the emissivity of the cavity, was compared to the radiance temperature, directly measured with a reference pyrometer, which was calibrated with a set of fixed point blackbodies. The difference was found to be within measurement uncertainties.

We summarize recent progress in our infrared (IR) spectral radiance metrology effort. In support of customer blackbody characterization, a realization of the spectral radiance scale has been undertaken in the temperature range of 232 °C to 962 °C and spectral range of 2.5 μm to 20 μm. We discuss the scale realization process that includes the use of Sn, Zn, Al and Ag fixed-point blackbodies (BB), as well as the transfer of the spectral radiance scale to transfer standard BBs based on water, Cs and Na heat pipes. Further we discuss the procedures for customer source calibration with several examples of the spectral radiance and emissivity measurements of secondary standard BB sources. For one of the BBs, a substantial deviation of emissivity values from the manufacturer specifications was found. Further plans include expansion of the adopted methodology for temperatures down to 15 °C and building a dedicated facility for spectral characterization of IR radiation sources.

Use of linear or concentric grooves is a well-known approach for increasing the surface emissivity to enable the construction of compact blackbody radiators, improve absorptance of stray radiation traps, baffles and thermal radiation detectors, as well as enhance thermal radiation transfer. Emitters with V-grooved surfaces are widely used as reference sources in radiation thermometry and radiometry. In the design phase of such devices, it is important to predict their performance. Most existing models are devoted to modeling isothermal linear grooves with purely diffuse or specular reflectance. Radiation behavior of concentric grooves differs from linear ones and becomes similar only for large values of the ratio of the radial coordinate to the groove period. This paper covers numerical modeling of isothermal and nonisothermal concentric grooves with mixed specular-diffuse reflection for various viewing conditions using Monte Carlo specialized software. It is shown that the temperature drop towards the peak of a groove might lead to a substantial decrease of the grooves' effective emissivity.

Mikron has been designing and manufacturing blackbody sources since 1970. During the 1990's Mikron introduced 8 ultra-precision freezing point blackbody calibration sources as fixed point, primary calibration standards for the checking of transfer standards at discrete temperatures assignments from 29.76°C, the melting point of gallium, to 1084.62°C, the freezing point of copper. All the blackbody sources were compared with NIST equivalent blackbody sources and the temperature uncertainties were established. These precision instruments have been installed in several institutes responsible for maintaining radiance standards. During the last two years, Mikron has added additional high precision, but variable temperature, blackbody sources for producing ultra-accurate radiance standards. These new blackbody sources overcome the limitation of freezing points that can produce only a single melt or freezing radiance standards. In all of the new blackbody sources very important criteria has been preserved. Flat and near flat unity of the emitter spectral emission response, the reconciliation of the measurement between radiometric and thermometric measurements to achieve a high degree of precision and repeatability. The models, which will be introduced in this paper, are as follows: Model M300X, an ultra-precision blackbody source for temperature measurement from 50.00° to 1100.0°C; Model M350, a precision blackbody source, exclusively designed for calibration of wide incidence angle of heat flux gauges, for temperatures of 300° to 1100°C corresponding to over 200KW/m2 of incidence radiance; and Model M345X12, an extended area blackbody source with Lambertian emitter and dimensions of 305X305 mm for precision non-uniformity correction (NUC) and calibration of the wide-angle thermal imagers.

The model M395 blackbody source represents an unusual and highly innovative approach for the design of a truly universal blackbody source, which satisfies the most demanding requirements of modern radiometric calibration needs. This is indeed a milestone step, taken by Mikron Engineers, to satisfy seemingly two irreconcilable design criteria up to now, an ability to reach extreme high temperatures of 2300°C and at the same time to satisfy the need for near ambient temperatures. Due to the unique design of heated cavity shape, higher emissivity factor of near unity is achieved. This feature alone allows the calibration of the infrared instrument with wavelength range from 500nm to 20.0μm with much higher precision than previously possible. The flatness of spectral emissivity eliminates the constant awareness of potential errors associated with longer wavelength instruments under calibration. Due to incredible slew rate of near 300°C per minute and temperature resolution of 0.1°C, model M395 has the ability to replace number of existing blackbody sources with in an industrial facility or research laboratory with smaller foot print. It takes only several minutes to reach to any desired set points. Highly uniform emitter temperature further insures that infrared instruments with different field of view are equally accurate during calibration.

Widening uses of Infrared Thermal Imagers, many having temperature measurement indication, calls into question the accuracy of indicated temperature values. The answer is not simple since there are two separate and distinct areas that impact any measurement, calibration and actual use. The two areas can be treated separately, since they are, in fact, separate conditions of instrument use, one ideally under well controlled and highly repeatable conditions. This report covers the topics associated with calibration. First, there is a generic review of typical Infrared Radiation Thermometer measuring instrument methods. Next, practices reported in the literature for IR Thermal Imagers are presented. Then these are compared with actual procedures and practices used by imager manufacturers. This last information was gathered through voluntary responses to a survey of equipment makers.

Silicon wafers become semitransparent at room temperature and at wavelengths more than 1.1 μm. Silicon wafers with an oxide film layer are also semi-transparent because the extinction coefficient of the film optical constants is negligible at visible and infrared wavelengths. We experimentally studied optical properties such as emissivity, reflectivity and transmissivity of silicon wafers with and without oxide films to devise new radiation thermometry that is applicable to semi-transparent silicon wafers near room temperature. The proposed radiation thermometry which is constituted from two blackbodies and p-polarized optical components showed the accuracy of ± 1 K at the temperature range from 313 K to 343 K using a radiometer with an InSb sensor sensitive at a wavelength of 4.7 ± 0.1 μm for silicon wafers with low resistivity. It turned out that radiation thermometry near room temperature for silicon wafers with resistivity over 1 Ωcm is very difficult because their emissivities are extremely small.

Recently, deterioration of concrete structures before their design life has become a serious social problem in Japan. Nondestructive inspection techniques are required, for detecting defects and damages in concrete structures, such as subsurface void or delamination. As one of these techniques, the thermographic NDT can be applied as an effective NDT technique to inspect large area of the objective structure from distant place. In addition, it does not require any chemicals and application of physical excitation for inspection. However, the thermographic NDT has a shortcoming that the measurement results are affected by the reflection of atmospheric radiation due to the sunlight, sky or surrounding materials. Since most of the buildings in Japan are covered with luster materials with low emissivity, such as tile or mortal, infrared reflection on the surface is difficult to be neglected. To reduce the influence of these reflection noises, the infrared thermography with detectable wavelength from 5 to 8 μm, which coincides with absorption range of moisture, is utilized. In this research, a new infrared thermography with 5 to 8 μm wavelength range by applying a band pass filter and an uncooled microbolometer infrared array detector. Further, a new signal to noise (S/N) ratio improvement technique has been developed in order to compensate a deterioration of sensitivity due to the band pass filter.

The farther away one can get from the subject of an infrared (IR) survey, while maintaining the needed spatial resolution and thermal sensitivity, the more usable the data becomes. This is the aerial IR advantage. Aerial IR applications can be divided into two groups; A) applications where a straight-down view and/or a large area view is needed and B) applications where long distances must be covered in a limited amount of time. Selection of aircraft, aircrew, navigational aids, avionics, infrared imaging system, analog and/or digital data acquisition systems and image processing systems are all important for successful surveying.

Launched from Kennedy Spaceflight Center in the early morning of August 25, 2003, NASA's Spitzer Space Telescope (formerly Space Infrared (IR) Telescope Facility, SIRTF) is the fourth and final facility in the Great Observatories Program. It joins Hubble Space Telescope (HST, 1990), the Compton Gamma-Ray Observatory (CGRO, 1991-2000), and the Chandra X-Ray Observatory (CXO, 1999). Spitzer has a sensitivity that is two to three orders of magnitude higher than that of previous ground-based and space-based infrared observatories. It is revolutionizing our understanding of the creation of the universe, the formation and evolution of galaxies, the genesis of stars and planets, and the chemical evolution of the universe. A brief overview of infrared (IR) astronomy and of Spitzer's role in the science of IR is given. The history, construction, launch, and in-orbit checkout of the observatory is reviewed. Science highlights from the first two and a half years of observations are presented. Further information about the Spitzer can be found on the WEB at http://spitzer.caltech.edu/.

The thermal radiation properties of different metals are taken over a large temperature range because they are needed as material data for construction and process control of thermal technical plants and for pyrometric temperature measurements. This includes non-ferrous metals and steel for heat up and heat treatment technologies as well as construction metals for high temperature installations and units. Metals are generally used for technical applications as specially alloyed materials, for which the thermo-physical properties in most cases are not sufficient known. That concerns also the radiative properties within the range of higher temperatures, which therefore have to be determined. Based on the treatment and application of metals in higher temperature ranges the emittance is the most qualified radiative property for use in heat transfer calculations and for adjustment of temperature measuring instruments. At the university of Duisburg-Essen measurements of spectral emissivities for a large number of metals are carried out. The measuring systems, based on a monochromator and a FT-IR-spectrometer are described. A survey of results for different metals is given. The influences of temperature and roughness are investigated. Other results lead to the existence of a so called X-point. The oxidation of metals show drastically changes of emissivities. For oxidizing steel the theoretical expected interferences of spectral emissivities could shown by measurements.

Image registration is in some senses the 'forgotten problem' in multi-sensor image exploitation. Image registration will, at present, typically involve using a constant registration transform to align images from sensors fixed relative to each other and separated by as small a distance as possible. For more challenging situations in which sensors are more widely spaced and not fixed relative to each other (e.g. teams of Uninhabited Air Vehicles, UAVs) the registration problem becomes far more complex. The theory of solving the registration problem for such situations is poorly understood with outstanding issues being the expected optimal image alignment, how to perform automatic registration, and methods of addressing time varying image registration. As a pre-cursor to the solution of such problems we present an analysis of the likely errors associated with more complex registration problems. Results of trials using current state-of-the-art technology are presented followed by initial concepts in improving these results.

We have constructed a novel filter wheel camera that allows filters to be rapidly and sequentially introduced into the optical path of a high-performance NIR (near-infrared) camera based on a staring focal-plane array (FPA) made with indium gallium arsenide (InGaAs) detectors. The filter wheel is populated with neutral density filters ranging from a transmission of 0.97 (essentially no attenuation) to ~10^-5 (an ND5 filter stack). The camera acquires images with increasing attenuation of signal in cycles of six images called subframes. Those images are collapsed into a single radiometrically-calibrated image (called a superframe) with a greatly extended dynamic range. In the current configuration of the system, the radiance dynamic range is about 4x10⁶, which is equivalent to 22 bits, a significant enhancement over the nominal 14-bit dynamic range of the camera core. This extended range makes it possible to make radiometric measurements on low ambient light scenes with tremendous variability of temperature or radiance, such as rocket launches, laser beams and intense flames. It is also possible to image scenes with high ambient near-infrared light levels, such as landscape on bright, sunny days without having to dynamically adjust exposure. Since the wheel rotates at high speed (15 Hz), the resulting dataset of six-frame cycles can be reduced to a superframe movie sequence with 15 Hz frame rate, making it possible to image spatially-changing scenes such as rocket launches with good image registration between subframes in a given cycle.

A new commercial camera with IR-Fusion^TM blends visible and infrared images into a single image. It uses a novel, low-cost, patent pending approach to solve the parallax problem and results in a camera with the image sharpness and clarity of a standard digital visible camera and the temperature measurement of an infrared camera. The camera can operate in three modes; 1) full screen visible, infrared or blended, 2) partial infrared image in a full screen visible image (picture-in-picture) and 3) infrared color alarm in a visible image. With the use of a laser pointer the camera operator can precisely identify locations on the target that correspond to specific points in the infrared image.

A new capability to acquire large amounts of spectrally determined optical data for a wide range of materials has been designed and developed from commercial off the shelf equipment. The software control system was written using LABVIEW 7.0. The Automated Rasterable Integrated Spectrometric and Total Integrated Scatter Measurement System (ARISTMS) represents a fusion of state-of-the-art technology and systems software to facilitate automated data acquisition to determine a material's spectral characteristics, surface roughness, and absorptance. It was developed as part of an ongoing Phase II SBIR effort to develop diffractively structured gallium arsenide infrared windows that are 100 mm in diameter transmitting between 1 and 10 microns. It was necessary to develop a capability that could scan or raster across the entire surface area of the window, vary the incident spot size, step size, and angle of incidence over the infrared spectrum of interest. The system offers a cost effective capability to screen many samples against preset thresholds for reflectance, transmittance, absorptance, and total integrated scatter for any number of measurement scenarios and sample classes.

In this paper we consider the issues involved in the 3D mapping of object surface temperatures from a system of thermal and normal stereo cameras. Of particular focus are issues related to integrated thermal and stereo camera calibration using a common visible and thermal calibration grid and the development of robust 3D thermal mapping algorithms that allow for seamless surface temperature calculations. Finally we have examined the class of objects that this system can robustly apply to as well as pinpoint deficiencies in such approaches to 3D surface temperature calculations from thermal cameras.

Adhesive bonded electrical heaters have been used in outside rearview mirrors of automobiles in order to act as defrosters. Entrapment of air pockets between the heater and the mirror can affects the performance and structural integrity of the mirror assembly. Since painting over the mirror is not an option in the production environment, the biggest challenge for IR imaging is to minimize surface reflection. Looking through a smooth, highly reflective first-surface mirror and a 2 mm thick glass without picking up other heat sources in the room, such as people, electronics equipment and the camera itself, requires careful planning and effective shielding. In this paper, we present our method of avoiding mirror reflection and IR images of the heated mirror in operation. Production heaters and heaters with artificial defect were studied. The IR imaging method has shown to be an effective tool for heater quality control and performance studies.

A Dual-band Radiometer (DBR) has been developed to accurately measure temperature at long ranges. Key to the DBR is a dual-band, quantum well infrared photodetector (QWIP) focal plane array (FPA) that integrates within each pixel both mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) spectral sensitivity. A vertically-integrated, two-color FPA eliminates with inter-band optical distortions, temperature-induced alignment errors, and improves radiometric measurement accuracy. The DBR system is sensitive to human targets, yet minimally sensitive to atmospheric conditions, enabling accuracy over the widest possible range of global conditions by using Two-color Imaging Radiometry (TCIR) to establish a target's absolute temperature within +/- 1°C. The benefits of TCIR for greybody measurements are absolute atmospheric transmission values are not required and uncorrelated shifts in the spectral band transmission cause minimal error. The system is packaged with an eye-safe laser rangefinder, GPS, and weather station suite, which provides real-time atmospheric measurements. These measurements are input to the USAF MOSART predictive atmospheric codes, which are used for real-time field calibration of the data. The magnification necessary to resolve facial features from 200 m to 750 m range requires a custom designed 6" diameter, f/7 telescope with temperature-stable optical alignment over a wide range of operational temperatures.

Fully cooked, ready-to-eat products represent one of the fastest growing markets in the meat and poultry industries. Modern meat cooking facilities typically cook chicken strips and nuggets at rates of 6000 lbs per hour, and it is a critical food safety issue to ensure the products on these lines are indeed fully cooked. Common practice now employs oven technicians to constantly measure final cook temperature with insertion-type thermocouple probes. Prior research has demonstrated that thermal imagery of chicken breasts and other products can be used to predict core temperature of products leaving an oven. In practice, implementation of a system to monitor core temperature can be difficult for several reasons. First, a wide variety of products are typically produced on the same production line and the system must adapt to all products. Second, the products can be often hard to find because they often leave the process in random order and may be touching or even overlapping. Another issue is finite measurement time which is typically only a few seconds. Finally, the system is subjected to a rigorous sanitation cycle and must hold up under wash down conditions. To address these problems, a calibrated 320x240 micro-bolometer camera was used to monitor the temperature of formed, breaded poultry products on a fully cooked production line for a period of one year. The study addressed the installation and operation of the system as well as the development of algorithms used to identify the product on a cluttered conveyor belt. It also compared the oven tech insertion probe measurements to the non-contact monitoring system performance.

We have developed the BioScanIR System based on QWIP (Quantum Well Infrared Photodetector). Data collected by this sensor are processed using the DIRI (Dynamic Infrared Imaging) algorithms. The combination of DIRI data processing methods with the unique characteristics of the QWIP sensor permit the creation of a new imaging modality capable of detecting minute changes in temperature at the surface of the tissue and organs associated with blood perfusion due to certain diseases such as cancer, vascular disease and diabetes. The BioScanIR System has been successfully applied in reconstructive surgery to localize donor flap feeding vessels (perforators) during the pre-surgical planning stage. The device is also used in post-surgical monitoring of skin flap perfusion. Since the BioScanIR is mobile; it can be moved to the bedside for such monitoring. In comparison to other modalities, the BioScanIR can localize perforators in a single, 20 seconds scan with definitive results available in minutes. The algorithms used include (FFT) Fast Fourier Transformation, motion artifact correction, spectral analysis and thermal image scaling. The BioScanIR is completely non-invasive and non-toxic, requires no exogenous contrast agents and is free of ionizing radiation. In addition to reconstructive surgery applications, the BioScanIR has shown promise as a useful functional imaging modality in neurosurgery, drug discovery in pre-clinical animal models, wound healing and peripheral vascular disease management.

Static Random Access Memory (SRAM) chips undergo several types of stress in the field, including thermal, electrical, and humidity stress. Existing work has concentrated primarily on humidity and thermal stress; there has been relatively little emphasis on voltage stress level prediction. The objectives of this investigation were to (1) explore the impact of voltage stress on SRAM functionality, (2) observe heating rate differences under voltage stress over time, (3) predict stress levels using artificial neural network models, and (4) develop a generic methodology for voltage stress prediction. A 62256 SRAM CMOS based chip located on an 8051 programming board was studied. Preliminary experiments suggest that as voltage and/or stress time increases, chip temperature increases as well. In addition, the combination of both factors causes the chip to fail within minutes of stress. Artificial neural network models with 3-2-1 and 3-3-1 topologies were constructed to predict stress level given heating rate over time. Thermal profiles of both the entire chip and the die area only were used for neural network model development and evaluation. Results indicate (1) high-voltage stress shortens the lifecycle of SRAM chips, (2) heating rate increases are relatively great in the first few minutes, then reach a steady state, and (3) the neural network model can predict stress level with good accuracy. Using data from the die area yielded the lowest average error rate (3.6 %) and using data from the entire chip yielded a 10% error rate. In addition, the trainRP learning function resulted in a lower error rate than other learning functions such as trainGD and trainCGP.

Static Random Access Memory (SRAM) chips undergo several types of stress in the field. Existing work has concentrated primarily on humidity and thermal stress; there has been relatively little emphasis on signal density stress prediction. Objectives of this study were to (1) explore the impact of signal density stress on SRAM functionality, (2) observe thermal profile differences under signal density stress over time, (3) predict stress levels using artificial neural network models, and (4) develop a generic methodology for signal density stress prediction. An 8051 programming board containing an SRAM chip was used. Two kinds of signal density stress were investigated - varying the content written to memory, and varying signal frequency in accessing SRAM through flash memory. Preliminary experiments suggest that both types of stress impact the SRAM thermal profile. Thermal profile data were used to build back propagation neural network models; 70% of the data was used to build the models and 30% was used for testing. Various neural network training functions and topologies were used to predict chip stress level given thermal profile data. Data from both the die area and the entire chip were used. For both types of stress, using data from the die area in a network with a 3-3-1 topology yielded the lowest average error rate - 1.3% for data content stress level prediction and 7.6 % for signal frequency stress level prediction. The trainRP function resulted in a lower error rate than other training functions that were evaluated.

Compactness and portability of MEMS sensors and actuators with dedicated power sources are governed not only by the size of the system components but also by the size and durability of the power source itself. This work is part of a project on the characterization and modeling of heat transfer of an on-chip assembly of RTDs (resistance temperature detectors), microthermocouples and thin films of different materials. In this paper, we investigate the effects of conductive and convective heat transfer on the response of an RTD. Especially, the effects of a range of pressures from atmospheric to near-vacuum conditions at different applied voltages on the electrical energy consumption of an on-chip RTD are investigated. The transient temperature - time response as well as the power consumption of the RTD under the aforementioned conditions are also reported. Conductive effects are far more important than any other heat transfer mechanism; these effects are quantified.

In the scope of the Megawatt Pilot Experiment MEGAPIE, i.e. the development of a liquid metal target for a spallation neutron source, an experimental thermo-hydraulics investigation of the target proton beam entry window cooling has been performed. Goal of this investigation concerned the measurement of the local convection heat transfer coefficient (HTC) inside of the proton beam entry window area of the MEGAPIE target, in particular: determination of HTC absolute values, distribution/visualization of HTC field shape and dynamic behavior of HTC field i.e. visualization of HTC field fluctuations. Within KILOPIE's experimental set-up the following conditions of MEGAPIE target have been fulfilled: Using of liquid metal (LM) lead-bismuth eutectic (LBE); this simultaneously serves as target material and coolant. Using of T91-steel; for the shell-dish of hemispherical mock-up of the proton beam entry window. Using of original geometry of piping insertions for the simulation of internal LBE coolant flow geometry. In KILOPIE the improved Two-Dimensional and Dynamic of Infrared Thermography (2DD-IRT) Method, presented on Thermosense XXII in year 2000, has been used. In this paper the improvements of 2DD-IRT method and some result of KILOPIE experimental investigations performed at PSI in Switzerland will be presented. A specially tailored Aluchrom-steel shell is used, which allows applying a uniform and known constant heat flux deposition on the outer surface of the T91-steel hemispherical mock-up of the target window. The optical non-contact IRT equipment measures the outer surface temperature of the Aluchrom-steel heater glued to the T91-steel mock-up dish. The determination of the local convection HTC is a result of ratio of the known local heat flux from the Aluchrom-steel heater to the difference between the local inner surface temperature of the T91-steel mock-up dish and the bulk temperature of the LBE coolant.

Walk-through portal detection systems are being developed to screen passengers for the presence of explosives in support of homeland security. These portals utilize a series of air-jets to remove the explosive particles for detection using ion mobility spectrometry. In this work, we describe the use of a thermal imager to visualize the flow from the nozzles with heated, pure CO₂ gas for enhanced emission. The thermal imaging is performed using an LN₂-cooled, InSb focal-plane array with a germanium lens. Since CO₂ gas at 300 K has a strong absorption centered at 4.3 μm which is isolated from other absorbing gases, a spectral filter centered at 4.4425 μm with a full-width half maximum bandwidth of 0.18 μm was used to detect the CO₂ emission. To increase the radiance from the gas, pure, heated CO₂ was ejected from the nozzle. The concentration of CO₂ in standard atmosphere is < 0.05 %, and thus the atmosphere is effectively transparent under laboratory conditions. As the temperature of the CO₂ is increased above room temperature, the emission increases according to Planck radiance law and also broadens to longer wavelengths, thus enhancing the collected signals. The thermal images were corrected for both spatial uniformity of responsivity and detector linearity with constant and variable-integration times using a large-area variable-temperature blackbody with known emissivity and temperatures. The correction algorithm using the blackbody at many different temperatures will be described. Corrected, thermal videos under both laminar and turbulent flow conditions are shown. Fine details such as residual CO₂ swirls cooled slightly below the ambient background are visible because of improved non-uniformity correction enabled by a differential imaging extension of the algorithm.

The paper deals with the possibility of using the differential thermography (Thermoelastic Stress Analysis) to predict the fatigue resistance of welded joints on the basis of the local stress/strain field at the weld toe. The study is inspired by a local strain method, the WEL.FA.RE. method, based on the local amplitude of strain ε_a measured by 3mm grid-length strain gauges bonded with the axis at a 2.5mm distance from the real weld toe. The WEL.FA.RE. method suggests to determine the fatigue limit of welded joints simply by means of an experimental curve and the measurements of the local amplitude of strain ε_a to the weld toe directly on the structure under service conditions. In this work, both strain gauge and TSA techniques have been used to this purpose. In order to understand the development of the fatigue phenomena, the entire local strain field to the weld toe has been monitored by means of the thermoelastic stress analysis (TSA) technique and the results have been compared to those obtained with strain gauge. Structural steel specimens have been fatigue tested under alternate symmetric loads (tension-compression) and the local strain amplitude to the weld toe has been measured with two experimental technique (strain gauge and thermoelastic stress analysis) and compared in view of choose which one is more suitable for the WEL.FA.RE. method. The analysis of the thermoelastic data has showed that TSA is able to provide adequate spatial resolution to describe the complexity of the strain field along the cord. Furthermore the phase image has turned out to be an effective parameter to assess the crack initiating and growth. So, thermoelasticity has the capacity to be used as a non destructive technique for the evaluation of the structural integrity of the welded joints.

An experimental analysis of the orthogonal cutting process is presented. Machining experiments have been performed using advanced techniques. A high-speed camera is coupled with an infrared thermal measurement aid on a dynamic test bench. This continuously reveals the deformations occurring on the flank of a chip, and the infrared camera gives information on the variation of thermal radiation (see the pictures under the abstract). The challenge consists of understanding the effect of machinability improvement treatments on metallic materials.

Thermal imaging cameras are rapidly becoming integral equipment for first responders for use in structure fires and other emergencies. Currently there are no standardized performance metrics or test methods available to the users and manufacturers of these instruments. The Building and Fire Research Laboratory (BFRL) at the National Institute of Standards and Technology is conducting research to establish test conditions that best represent the environment in which these cameras are used. First responders may use thermal imagers for field operations ranging from fire attack and search/rescue in burning structures, to hot spot detection in overhaul activities, to detecting the location of hazardous materials. In order to develop standardized performance metrics and test methods that capture the harsh environment in which these cameras may be used, information has been collected from the literature, and from full-scale tests that have been conducted at BFRL. Initial experimental work has focused on temperature extremes and the presence of obscuring media such as smoke. In full-scale tests, thermal imagers viewed a target through smoke, dust, and steam, with and without flames in the field of view. The fuels tested were hydrocarbons (methanol, heptane, propylene, toluene), wood, upholstered cushions, and carpeting with padding. Gas temperatures, CO, CO₂, and O₂ volume fraction, emission spectra, and smoke concentrations were measured. Simple thermal bar targets and a heated mannequin fitted in firefighter gear were used as targets. The imagers were placed at three distances from the targets, ranging from 3 m to 12 m.

Performing infrared imaging and analysis on buildings or structures is challenging on a good day. More often than not, scanning an entire multi-story building will take several days. It requires patience from the thermographer because he has to let the sun to do its job solar loading the building, or, he may have to wait for the building to radiate its solar load in the cool of the evening. Usually this takes a "whatever the study requires" state of mind and the days are long. An experienced eye is also required to understand the nuances of construction and subtle temperature variations as they appear in an infrared image. Even with optimal conditions and a good uniform solar load, a strong thermographic indication can trip you up when it travels around a corner or into shadows. This condition can frustrate the thermographer, and also make the job longer because he has to wait for the sun to load into the next area of interest to chase out the indication. How do you get around this? This paper presents thermographic techniques to help image indications that run from uniform solar load around corners or through shadows.

There are a number of paintings in the McClung collection [East Tennessee History Center] by East Tennessee artists of some notoriety. In the cleaning process, curators had noticed that a painting attributed to Lloyd Branson is actually painted over a previous painting or drawing. This underdrawing is only partially visible with the naked eye. Infrared Reflectography was used to detect and document the underdrawing. The top painting is oriented in the portrait direction with the subject being an American Civil War general by the name of John P. McCown. The underdrawing is oriented in the landscape direction with the subject being a mill scene, complete with a water wheel. Contrast optimization through the use of filters and spatial resolution enhancement by assembling a mosaic from a set of close-up images will be discussed.

The certification procedure of building thermographers was started in 2003, even though thermography has been used in Finland in building survey since late 70's. There has been about a 25 years' unorganized and more or less wild period, without any generally accepted rules for interpretation, as well as how to order thermography services, how to report the results, how to do the practical work in the buildings etc. The service was provided by consultants with varied backgrounds. More operators have come into the market and building developers and contractors have begun to use thermography for quality control in new building and in renovation planning. In the year 2004 various organizations in building trade launched a pilot project to certificate building thermographers. The structure and the topics of the course were introduced in Thermosense 2005. By the end of the year 2005 the third course was completed. From the beginning of the procedure to the end of the third course about 40 persons have received a certificate. During the certification process, two guidelines have been published, as part of RT (Building Information) - files: instructions for ordering, for practical field work and for reporting of thermography survey in buildings. The guidelines also contain basics for interpretation. The interpretation is consistent with the other existing directions (building codes etc). At the turn of 2005 - 2006 a new book of building thermography was published. There is still lack of comprehensive as well as unambiguous rules for interpretation. In the paper we will present experiences on the courses, the main problems posed to the participants and findings during the last two - three years' field work. We will also introduce briefly the structure and content of the guidelines and an example how to use thermography as a tool of quality control in new building. The case studies are new one-family houses in a housing fair and exhibition area in the city of Oulu.

Within the past five years, the Pest Management industry has become aware that IR thermography can aid in the detection of pest infestations and locate other conditions that are within the purview of the industry. This paper will review the applications that can be utilized by the pest management professional and discuss the advanced techniques that may be required in conjunction with thermal imaging to locate insect and other pest infestations, moisture within structures, the verification of data and the special challenges associated with the inspection process.

Since its introduction 5 years ago, the Thermographic Signal Reconstruction (TSR) method has become a widely accepted approach to processing and interpreting active thermography data. Although the technique generates a noise free replica of an experimental data sequence, it is the time derivatives of the replica that have proved to be most useful. In particular, the second derivative of the TSR signal offers increased sensitivity, noise and artifact suppression and reference-free evaluation and quantification of results. Unlike contrast methods, where a point is evaluated by comparison to a defect-free reference, the TSR second derivative of a single pixel indicates the presence of a subsurface defect, or in the absence of a defect, it can be used to measure the local thermal diffusivity.

In this paper, we review some of the discrete signal transforms that are in use in the field of thermography for defect detection and/or characterization. Signal transformation is used with the purpose of finding an alternative domain where data analysis is more straightforward. For instance, it is possible to pass from the time domain to the frequency spectra through the one-dimensional discrete Fourier transform (DFT). The DFT constitutes the basis of pulsed phase thermography (PPT), but other transformations are possible such as the discrete wavelet transform (DWT) with the advantage that, in this case, time information is preserved after the transformation. It is also possible to rearrange data into domains others than frequency. For instance, the Hough transform (HT) allows the detection of regular forms (e.g. lines, curves, etc.) in a parameter space. The HT has been used in two different ways in thermography: for the detection of lines in thermal profiles, with the goal of discriminating between defective and non-defective regions; or it can be used to locate the inflection points in phase profiles obtained by PPT to extract the blind frequencies. The Laplace transform can also be used in the time domain to improve flaws detection and their characterization in the transformed space. Eigenvector-based transforms, such as singular value decomposition (SVD), have also been implemented. Principal component thermography (PCT) uses SVD to decompose thermographic data into a set of orthogonal modes. We discuss all these transforms and provide some comparative results.

A recently proposed novel technique for thermal non-destructive characterization based on digitized frequency modulated thermal waves is described. Defect detection in metallic, composite and semiconductor samples are presented as applications of digitized frequency modulated thermal wave imaging (DFMTWI). High peak power heat source requirement in pulsed thermography, and limited depth resolution of lock-in thermography due to fixed modulating frequency of sources, are over come by the proposed new technique by use of appropriately modulated excitation signal, limited both in time duration and frequency bandwidth.

In this work, infrared thermography (IRT) was used for the investigation of structural materials using the active approach. Four types of building materials were examined; three types of porous stone (from Rhodes, Cyprus, Rethymno - Crete) and one type of marble (Dionysus). Specimens containing self-induced defects of known dimensions and depths were studied. The samples were heated externally (thermal excitation) and thermograms were recorded continuously at the transient phase. Mathematical - thermal modelling enabling the modelling of the investigated subsurface defects, using the thermocalc 3-D software, was also implemented. Then, quantification analysis (i.e. temperature - time plots, as well as thermal contrast curves) from the experimental tests, as well as from the use of thermal modelling runs took place, indicating the thermal behaviour of building materials containing such defects. The results of this research show that IRT can be used for the detection and quantification of defects in structural materials.

The simple approach to estimating corrosion detection limits in thick metallic samples has been proposed by taking into account 3D heat diffusion phenomena for circle-like defects. Experimental data has been obtained for both flash and long heating of steel samples with the thickness up to 10 mm.

There is a growing international interest in thermal inspection systems for asset life assessment and management of defense platforms. The efficacy of flash thermography is generally enhanced by applying image processing algorithms to the observations of raw temperature. Improving the defect signal to noise ratio (SNR) is of primary interest to reduce false calls and allow for easier interpretation of a thermal inspection image. Several factors affecting defect SNR were studied such as data compression and reconstruction using principal component analysis and time window processing.

The paper contains theoretical and experimental thermal diffusivity data on anisotropic carbon and glass fiber reinforced composite laminates up to 5 mm thick. The effectiveness of the theory is evaluated by using a 3D numerical model. Both spot-mask and slit-mask techniques for determining lateral thermal diffusivity components are analyzed.

Pulse heating infrared thermography method was applied for NDE of low energy impact delamination damages in test sample of CFRP pressure vessels employed for space. Size and depth of delamination damage in CFRP pressure vessel samples were quantitatively determined from sequential temperature distribution data after pulse heating using data processing methods developed by the present authors. The Fourier analyses were applied to the temperature decent curves after pulse heating obtained at each pixel of the sequential thermal images. Coefficients of the Fourier series were calculated from temperature decent curves, and they were effectively used to determine defect parameters such as the defect area and the defect depth. The feasibility of the proposed nondestructive inspection techniques was demonstrated by the experimental investigations using CFRP pressure vessel test samples.

Since the Space Shuttle Columbia accident, NASA has focused on improving advanced NDE techniques for the Reinforced Carbon-Carbon (RCC) panels that comprise the orbiter's wing leading edge and nose cap. Various nondestructive inspection techniques have been used in the examination of the RCC, but thermography has emerged as an effective inspection alternative to more traditional methods. Thermography is a non-contact inspection method as compared to ultrasonic techniques which typically require the use of a coupling medium between the transducer and material. Like radiographic techniques, thermography can inspect large areas, but has the advantage of minimal safety concerns and the ability for single-sided measurements. Details of the analysis technique that has been developed to allow in situ inspection of a majority of shuttle RCC components is discussed. Additionally, validation testing, performed to quantify the performance of the system, will be discussed. Finally, the results of applying this technology to the Space Shuttle Discovery after its return from the STS-114 mission in July 2005 are discussed.

Designed to fulfill a critical inspection need for the Space Shuttle Program, the EVA IR Camera System can detect crack and subsurface defects in the Reinforced Carbon-Carbon (RCC) sections of the Space Shuttle's Thermal Protection System (TPS). The EVA IR Camera performs this detection by taking advantage of the natural thermal gradients induced in the RCC by solar flux and thermal emission from the Earth. This instrument is a compact, low-mass, low-power solution (1.2cm3, 1.5kg, 5.0W) for TPS inspection that exceeds existing requirements for feature detection. Taking advantage of ground-based IR thermography techniques, the EVA IR Camera System provides the Space Shuttle program with a solution that can be accommodated by the existing inspection system. The EVA IR Camera System augments the visible and laser inspection systems and finds cracks and subsurface damage that is not measurable by the other sensors, and thus fills a critical gap in the Space Shuttle's inspection needs. This paper discusses the on-orbit RCC inspection measurement concept and requirements, and then presents a detailed description of the EVA IR Camera System design.

The purpose of this paper is to describe an infrared inspection system for highly reflective and low emissive materials. The detection system was developed for identifying surface irregularities such as cracks, pits, scratches and holes in part that are made of materials having high reflectivity and a low emissivity, such as polished titanium, aluminum, a silicon panels. In this technique, a laser beam is focused to a diameter that is approximately 50 microns or less that scans across the surface of the part under inspection. Energy from the beam is trapped inside a crack or pit, which results in a significant thermal gradient increase. This high thermal gradient will overcome the reflection from the surroundings and can be detected by an infrared imager.

Eddy current thermography uses an induction coil to induce eddy currents in conductive materials. The involved resistive losses heat the sample. By modulation of the eddy current amplitude, thermal waves are generated which interact with boundaries thereby revealing defects. Conventional eddy current testing has only a limited depth range due to the skin effect of metal samples. In Induction-Lockin-Thermography (ILT) the depth range is extended by the thermal penetration depth. An infrared camera monitors the modulation of the temperature field on the surface as a response to the coded excitation thereby allowing for fast imaging of defects in larger areas without the need of slow point-by-point mapping. This response is decoded by a Fourier analysis at the modulation frequency. So the extracted information is displayed by just two images where one displays local amplitude and the other local phase. ILT has significant advantages as compared to inductive heating with visual inspection of the thermographic sequence: Phase angle images are independent of most artifacts like reflections, variation in emission coefficient, or inhomogeneous heating. Due to the performed Fourier analysis of the temperature image sequence, the signal-to-noise ratio in the amplitude and phase images is significantly better than in single temperature images of the sequence. Induction heating is confined to conductive materials. However, it is applicable not only to metals but also to carbon fiber reinforced laminates (CFRP) or carbon fiber reinforced ceramics (C/C-SiC). The presented examples for applications of ILT illustrate the potential and limitations of this new non-destructive inspection method.

Ultrasound activated Lockin-Thermography ("ultrasound attenuation mapping") is a defect selective NDT-technique. Its main advantage is a high probability of defect detection ("POD") since only defects produce a signal while all other features are suppressed. The mechanism involved is local sound absorption which turns a variably loaded defect into a heat source. Thermographic monitoring of elastic wave attenuation in defects was reported for the first time in 1979 by Henneke and colleagues for continuous and pulsed ultrasound injection. Later, amplitude modulated ultrasound was used to derive frequency coded phase angle images combining defect-selectivity with robustness of measurement. With mono-frequent ultrasound excitation a standing wave pattern might hide defects. With additional modulation of the ultrasound frequency such a misleading pattern can be minimized. Applications related to quality maintenance (aerospace, automotive industry) will be presented in order to illustrate the potential of frequency modulated ultrasound excitation and its applications.

An airborne gas detection IR system which includes a laser, infrared imager and video-recorder is described. The sensitivity of the system to leaks from ground pipelines by the laser channel is about 100 ppm*m at 100 m (by methane). The IR thermographic channel plays an auxiliary role and the video channel allows better coordinate positioning of detected gas leaks in conjunction with a built-in GPS device.

Steel pipes used at Alaskan oil-producing facilities to transport production crude, gas, and injection water between well house and drill site manifold building, and along cross-country lines to and from central processing facilities, must be insulated in order to protect against the severely cold temperatures that are common during the arctic winter. A problem inherent with this system is that the sealed joints between adjacent layers of the outer wrap will over time degrade and can allow water to breach the system and migrate into and through the insulation. The moisture can ultimately interact with the steel pipe and trigger external corrosion which, if left unchecked, can lead to pipe failure and spillage. A New Technology Evaluation Guideline prepared for ConocoPhillips Alaska, Inc. in 2001 is intended to guide the consideration of new technologies for pipeline inspection in a manner that is safer, faster, and more cost-effective than existing techniques. Infrared thermography (IRT) was identified as promising for identification of wetted insulation regions given that it offers the means to scan a large area quickly from a safe distance, and measure the temperature field associated with that area. However, it was also recognized that there are limiting factors associated with an IRT-based approach including instrument sensitivity, cost, portability, functionality in hostile (arctic) environments, and training required for proper interpretation of data. A methodology was developed and tested in the field that provides a technique to conduct large-scale screening for wetted regions along insulated pipelines. The results of predictive modeling analysis and testing demonstrate the feasibility under certain condition of identifying wetted insulation areas. The results of the study and recommendations for implementation are described.

Stephan's problem of a freezing front propagation inside a multilayer objects is discussed. For to solve this problem in practice numerical methods are used to integrate moisture and heat transfer equations while calculation of the current frost pane's coordinate inside external multilayer building envelopes whose surfaces' temperatures are measured over a while. When the Stephan's equation integration takes place, the phase transformation is taken into account by means of a sharp jump of the material's specific heat capacity at the point of the phase transformation. Examples of such calculation of the frost pane coordinate dependency of time inside multilayer constructions are presented. An algorithm of the current dew point coordinate determination inside multilayer objects is suggested.

Averaged heat transfer resistance of the building envelope is the primary parameter that determines the energy saving characteristics of the building. At the phase of the building design it is usually taken into account that building must preserve heat effectively. It is mostly important in northern countries where cold seasons last for more than a half of year. Usually infrared methods are used to find mechanical defects of the building envelope. In this article an alternative way to describe the building envelope using infrared camera is presented. The method includes the determination of local heat engineering characteristics of the envelope using contact measurements and the determination of averaged heat transfer resistance of the buildings envelope using its infrared image.

Bridge is indispensable as social overhead capital. In the past, concrete construction was believed to be semi-permanent. Actually, however, concrete is deteriorated by various factors including seawater damage, annual temperature change, etc. Therefore, it is now obvious that maintenance and management are essential to keep performance of the bridge. In Japan, we had many reports of using infrared thermography for diagnosis of building, mainly for delamination of tile and mortar used for surface of the building for more than 10 years. In recent years, infrared thermogrephy is more actively used for delamination of surface of the bridge. Passive method is usually used for open-air concrete structure diagnosis, which utilizes intraday environmental temperature change and/or radiation energy emitted from the sun which create delta-T of delamination portion of the concrete structure. It is very important to take thermal image at right conditions. Otherwise, you may easily fall onto false diagnosis. In our presentation, many case examples and study of thermal data will be shown, which are taken at the right condition.

In the research of application potential of water mist fire suppression system for fire fighting in train luggage carriage, a series of experiments were conducted in ISO room on wood crib fire with and without water mist actuation. The results of free burn test without water mist suppression are used as reference in evaluating the efficiency of water mist suppression system. As part of the free burn test, several tests have been done under the hood of ISO room to calibrate the size of the crib fire and these tests can also be used in analyzing the wall effect in room fire hazard. In these free burning experiments, wood cribs of four sizes under the hood were tested. The temperature of crib fire, heat flux around the fire, gas concentration in hood of ISO room were measured in the experiments and two sets of thermal imaging system were used to get the temperature distribution and the typical shape of the free burning flames. From the experiments, the radiation intensity in specific positions around the fire, the effective heat of combustion, mass loss, oxygen consumption rate for different sizes of fire, typical structure of the flame and self extinguishment time was obtained for each crib size.

The automatic detection of subsurface defects has become a desired goal in the application of Non Destructive Techniques. In this paper, a new algorithm based on the Radon Transform is proposed to reduce human intervention to a minimum in the field of Thermography for defect detection and/or characterization. The analysis of a thermographic sequence for the detection of subsurface defects can be reduced to the identification of the -0.5 slope in the surface temperature decay for each pixel within the image. Employing techniques commonly used in computer vision, an algorithm can be developed in order to look for the -0.5 slope in the temporal temperature decay profiles of each pixel. In our case, the Radon transform can be used to detect those -0.5 slope lines in the temporal temperature decay profiles. The final result provided by this algorithm is an image showing the different defects avoiding the necessity of evaluating parameters as relevant in other algorithms as the delayed time of the first image or any subjective point of view in the analysis. All the information is contained in only one image and leads to a quantitative estimation of the defect depths. The principal limitation is that the specimens under inspection should be semi-infinite homogeneous samples because this algorithm is supported on a 1-D Fourier diffusion equation approximation. Experimental works using a Plexiglas^TM specimen were performed showing a good agreement with other semi-automated techniques.

An inspection process of radiant heaters is presented in this paper. The proposed non destructive testing and evaluation (NDT and E) technique for defect assessment of radiant heaters is based on infrared thermography images properly acquired and processed. The technique can be used in on-line fabrication quality control radiant heaters manufacturing processes. By exciting the heater with a very short electrical pulse, a sequence of thermographic images is captured by an infrared camera and then analyzed. Regardless of the electrical excitation applied to the heating element of the heater, the electrical power supplied will dissipate at the resistor. Provided enough spatial resolution, the heaters could be tested with an infrared camera capturing the radiated heat. The analysis of the heating wire during the heating flank shows differences among pixels corresponding to defective points and pixels belonging to non-defective areas of the wire. The automation is provided by the development of an algorithm that looks for the slope of the heating evolution of each pixel. A Radon Transform based algorithm is here proposed to reduce human intervention providing just one image where an operator could quickly locate possible defects.

A general solution of the inverse problem of nonstationary heat conductivity in multilayer objects based on Fourier expansion of time dependencies of the surface temperatures is considered. An example of a thermophysical properties determination in the case of a three-layer object is presented. An influence of the measuring equipment precision on the determined values of the characteristics is investigated. It is illustrated that the presented method provides a satisfactory precision in a wide range of amplitude values of measuring equipment noise.

The Infrared Development and Thermal Structures Laboratory (IDTSL) is an undergraduate research laboratory in the College of Integrated Science and Technology (CISAT) at James Madison University (JMU) in Harrisonburg, Virginia. During the 1997-98 academic year, Dr. Jonathan Miles established the IDTSL at JMU with the support of a collaborative research grant from the NASA Langley Research Center and with additional support from the College of Integrated Science and Technology at JMU. The IDTSL supports research and development efforts that feature non-contact thermal and mechanical measurements and advance the state of the art. These efforts all entail undergraduate participation intended to significantly enrich their technical education. The IDTSL is funded by major government organizations and the private sector and provides a unique opportunity to undergraduates who wish to participate in projects that push the boundaries of non-contact measurement technologies, and provides a model for effective hands-on, project oriented, student-centered learning that reinforces concepts and skills introduced within the Integrated Science and Technology (ISAT) curriculum. The lab also provides access to advanced topics and emerging measurement technologies; fosters development of teaming and communication skills in an interdisciplinary environment; and avails undergraduates of professional activities including writing papers, presentation at conferences, and participation in summer internships. This paper provides an overview of the Infrared Development and Thermal Structures Laboratory, its functionality, its record of achievements, and the important contribution it has made to the field of non-contact measurement and undergraduate education.