Variety of factors interact to produce a signal, received by the infrared imaging or measuring instruments. Spectral relationships can be recognized mainly as result of numerical modeling or highly specialized measurements. This paper presents elaborated models and many examples of computer simulation that use typical examples of measuring devices based on the photon and thermal detectors, as well as chosen results of experiments. Methods of spectral optimization of the IR sensing devices which base on the spectral contrast coefficient and simple method of spectral characteristics approximation are proposed. The aim of this paper is to help in understanding spectral phenomena that occur during the measurements, particularly in outdoor conditions.

The improvement of the combustion performance in combustor engines in terms of the reduction of the pollutant emissions is an important objective in Automotive and Aerospace Research and Development. Many phenomena occur during the spray injection in the combustor engine: droplet turbulent dispersion, droplet wall interaction, droplets interaction, droplet evaporation, primary and secondary breakup, auto- ignition, combustion, etc. To improve and to validate the heat exchange models between the droplet and a heated wall, an experimental set-up is developed at the ONERA Toulouse Centre on fundamental studies involving single droplets. An Infrared detector measures the temperature evolution of the surface droplet which impinges on a heated wall.

Hot-foil infrared thermography was employed to measure instantaneous local heat transfer coefficients of falling wavy films. The film flows down an electrically heated thin metal foil which provides a defined heat flux. The heat transfer coefficient of the film flow is evaluated from the temperature on the backside of the foil measured by an infrared camera. Good agreement of the instantaneous measurements with own numerical calculations points out the remarkable sensitivity and time resolution of the technique. The accuracy of the results is confirmed by comparison with recently published time averaged data.

Thermal transients caused by electrical switching devices and fast optical or electrical pulses only exist for a very short time (less than 1 millisecond). If the transient happens in a high thermal conductivity material, e.g. silicon wafer, the thermal transient will disappear in a few milliseconds or faster. Most modern IR cameras have external triggering capability. However, the IR camera often runs on its own clock. If the triggering of data acquisition is not synchronized with the camera, there is often an uncertainty of timing, e.g. 16.7 ms for camera running at 60Hz. Even when the IR camera is running at 500 Hz, there is 2 ms uncertainty. Depending on when you push/click the button, the high-speed thermal transients can be missed and they will disappear in the next image. We developed a technique to synchronize the IR camera to capture the thermal transients. By using a delay function, we can control the data acquisition very precisely to study the thermal transients.

This paper describes the use of the Phoenix infrared camera system in the area of high speed laser research. The Phoenix camera is a highly modularized, high performance system, developed by Indigo Systems Corporation to fully exploit the features inherent to Indigo's line of standard readout IC (ROIC) chips. Among the features supported, several are of particular relevance to work in the areas of laser gated imaging and beam profiling. These include windowing capability to greater than 10 KHz; pre-programmed acquisition sequences to support event profiling; a variety of synchronization modes to synchronize the camera to external events as well as external events to the camera, a built-in programmable trigger delay and a full 14-bit data path. Several examples of ongoing basic research will be presented to illustrate the use of these features.

EMIR technique is now able to measure the polarization of EM fields, thanks to highly anisotropic photothermal films. The films and the numerical model used to evaluate their electromagnetic behavior are described. Based on the use of a model, a thermal optimization of the sensor, taking into account the amplitude modulation frequency, is presented. The technique is applied to the analysis of the EM field, at 12 GHz, in the vicinity of the end of a waveguide. Validation is achieved through comparison of the experimental results to theory.

To ensure the reliability of printed circuit boards, stress tests are typically applied throughout the manufacturing process to screen out weak/marginal boards. Existing tester diagnostic programs are used to detect failures and human technicians can then narrow down the source of the failure to a set of components. However, it is difficult to pinpoint the exact defective components. The objectives of this study were two-fold: (1) evaluate feasibility and applications of thermal signature for stress failure diagnosis; and (2) assess thermal signature portability at the component level. The stress failures under investigation were (1) stress test failure and (2) environmental stress screening test failure. Preliminary results suggest that thermal signature can be used as a diagnostic aid to technicians or engineers in diagnosing boards with stress failures. In addition, the same component, when placed on different boards or in different locations on the same board, has a similar thermal signature.

Over the last 55 years, direct-view televisions have evolved from small black-and-white models to large, color models. Screen area has increased thirty-fold, requiring thicker glass to support the high vacuum load in the picture tube. The largest tubes now require more than 140 lbs. (65 kg) of glass, and are more than 1 inch (2.5 cm) thick in the screen area. These newer, larger televisions must support high- resolution digital signals, with much tighter requirements for screen inside contour and image quality. Manufacturing these large, thick, high-quality screens on old production lines is very challenging. This paper describes some of the ways that thermal imaging is used to meet these challenges. Some uses are simple, such as predictive maintenance inspections common in many factories. Other uses are more complex, such as evaluating metal wear in press equipment and providing data to validate complex models of glass forming. This paper also explores some of the special requirements placed on thermal imaging equipment in a television glass plant. Among other things, these include high operating and ambient temperatures (greater than 1000 degrees C) and the ability to measure temperatures in both highly reflective and semi-transparent materials.

A two-wavelength, imaging pyrometer was developed for real- time measurement of the surface temperature distribution of a spray-formed steel billet. This new spray-forming process is used to deposit bulk steel on a ceramic substrate in a surface temperature range of 300 degrees C to 400 degrees C, using four, twin-wire arc plasma torches. These steel billets are used as tools in metal forming processes, injection molding and die casting tools, and other processes that may need hard tooling, such as the automotive industry. The steel billet must be formed with a uniform, surface temperature distribution to minimize the thermal stresses within the steel, throughout the process. The imaging pyrometer uses a near-IR InGaAs CCD camera with high quantum efficiency from 0.95 to 1.75 microns. The wavelengths of 1.40 and 1.65 microns were selected to sense the low temperature billet. The camera has a format of 320 x 240 pixels with a pixel spacing of 30 microns and an integral 12-bit A/D converter with both video and digital outputs. The design of the pyrometer provides a working distance of 2.2 meters and a field of view of 0.6 meters. This technical paper describes the calibrations and initial measurement results obtained in a spray forming facility at the Ford Research Laboratory. The calibration provided intensity ratio measurements for surface temperatures ranging from 200 degrees C to 300 degrees C, the expected range of operation. The initial measurements described here depict the surface temperature distribution of the steel billet throughout the spray forming process, typically lasting several hours.

During machining process the knowledge of the temperature is the most important factor in tool analysis. It allows to control main factors that influence tool use, life time and waste. The temperature in the contact area between the piece and the tool is resulting from the material removal in cutting operation and it is too difficult to be obtained because the tool and the work piece are in motion. One way to measure the temperature in this situation is detecting the infrared radiation. This work presents a new methodology for diagnosis and monitoring of machining processes with the use of infrared images. The infrared image provides a map in gray tones of the elements in the process: tool, work piece and chips. Each gray tone in the image corresponds to a certain temperature for each one of those materials and the relationship between the gray tones and the temperature is gotten by the previous of infrared camera calibration. The system developed in this work uses an infrared camera, a frame grabber board and a software composed of three modules. The first module makes the image acquisition and processing. The second module makes the feature image extraction and performs the feature vector. Finally, the third module uses fuzzy logic to evaluate the feature vector and supplies the tool state diagnostic as output.

The bonding of steel pieces and the development of novel soldering methods, appropriate to the extended variety of applications of steels nowadays, bring the sensing of temperature an outstanding role in any metallurgical process. Transient liquid phase bonding (TLPB) processes have been successfully employed to join metals, among them steels. A thin layer of metal A, with a liquids temperature T_LA, is located between two pieces of metal B, with a liquids temperature T_LB higher than T_LA. The joining zone is heated up to a temperature T(T_LA<T<T_LB) and a bonded product with a near homogeneous composition is obtained. The most relevant parameter of the process is the bonding temperature T. The TLPB process for steel is performed in a 30 Kw induction furnace at temperatures in the range 800 degree(s)C to 1400 degree(s)C depending on the layer metal. A small window was opened between the central loops of the coil in order to observe the radiation emitted by the hot steel zone. A low price black and white CCD camera with 752x582 pixels has been adapted for temperature measurements through the coil of the furnace. The output of the camera is digitized and visualized in a 14-inch monitor. The temperature is calculated using the correlation with the gray tone present in the monitor, which is measured by means of suitable software. The technical specifications of the camera and the modifications introduced to adapt it for this work are presented. The calibration of the camera and the method employed in the measurements are described. The measured temperatures are corrected by the effect of emissivity of the materials surfaces and the environment radiation reflected. Thermographs obtained are shown and results are discussed. We conclude that a low priced camera may be used to measure temperature in this range with acceptable accuracy.

The precision measurement and recording of high speed thermal transients on microscopic targets is critical to the manufacturing of semiconductors and other electronic devices as thermal budgets become over more demanding and devices become more compact and powerful. This paper describes the fully automated emissivity- corrected measurement of high speed thermal pulses at speeds up to 200 KHz representing the newest innovation in almost 25 years of thermal microimager evolution. Sample thermal images and time-based thermal scans are presented demonstrating the use of this transient measurement capability in the detection and identification of design and process defects. The documentation of a measurement spatial resolution of better than 3 micrometers is also reviewed.

Infrared or thermal imaging systems are currently in use, and have been since the 1980's, by hundreds of major law enforcement agencies throughout the United States and recently Canada. U.S. Federal law enforcement agencies have employed the technology vigorously since the early 1970's, mainly in a surveillance role. Recent design advances have made thermal imagers more portable, and easier to maintain and operate. Also, coupled with the increased need for specialized investigative surveillance capability, particularly in the area of drug intervention, the technology has vastly expanded its applications within the law enforcement community. Manufacturers are producing thermal imagers that are less expensive and easier to obtain by smaller law enforcement agencies through grants and asset seizure funding.

Thermal imaging sensors have completely changed the way the world views fire and rescue applications. Recently, in the uncooled infrared camera and microbolometer detector areas, major strides have been made in manufacturing personal fire and rescue sensors. A family of new amorphous silicon microbolometers are being produced utilizing low cost, low weight, ultra low power, small size, high volume vacuum packaged silicon wafer-level focal plane array technologies. These bolometers contain no choppers or thermoelectric coolers, require no manual calibration and use readily available commercial off-the-shelf components. Manufacturing and packaging discoveries have allowed infrared sensitive silicon arrays to be produced with the same methods that have driven the rapidly advancing digital wireless telecommunications industries. Fire and rescue professionals are now able to conduct minimum time thermal imaging penetration, surveillance, detection, recognition, rescue and egress while maintaining situational awareness in a manner consistent with the modern technological applications. The purpose of this paper is to describe an uncooled micro bolometer infrared camera approach for meeting fire/rescue wants, needs and requirements, with application of recent technology advancements. This paper also details advances in bolometric focal plane arrays, optical and circuit card technologies, while providing a glimpse into the future of micro sensor growth. Technical barriers are addressed in light of constraints and lessons learned around this technology.

Airborne thermal infrared (IR) imaging technology is gaining wide acceptance as a large area survey technique for the detection and mapping of environmental contamination. A unique and very specialized subset of this application centers on the environmental issues related to the presence and dangers of military-originated unexploded ordnance (UXO). In fact, the UXO problem has emerged as one of the Department of Defense's most pressing environmental concerns. To help manage the issues associated with UXO contamination the subject can be further broken down into two integrally related areas. The first is the global humanitarian problem surrounding the approximately 100 million land mines left in place following military actions around the world, a problem which translates into thousands of civilian casualties annually. The second is the estimated 27 million acres in the United States contaminated with surface and buried munitions as a direct result of formerly used defense site (FUDS) activities rendering those lands unavailable for public or commercial use conversion. Through the application of various airborne IR imaging strategies at several of these FUDS locations, an airborne suite of technologies, and the process to acquire and analyze the resultant data, have evolved as a field ready system for the detection and mapping of this UXO material. The IR based hardware and application strategy now deployed have shown significant promise as a contributing technology in the long term solution for the non-tactical detection, identification, and mapping of buried and surface munitions around the world. This paper will explore the difficulties encountered with this application and will discuss results from a technology demonstration program conducted at the Dugway Proving Grounds, Utah.

The new generation of dedicated satellites for remote sensing of forest fires now in advanced development demands validation measurements from airborne platforms. A digital image acquisition system in the medium infrared (MIR) and thermal infrared (TIR) bands has been set up specifically for imaging of fires. The system provides simultaneous, co- registered and radiometrically calibrated MIR and TIR images. This makes it possible to use image processing techniques based on pixel-by-pixel comparison of MIR and TIR brightness temperatures. Analysis of a laboratory flame and a wood bonfire shows that the MIR-TIR scatterplot can be used to classify the scene into different fire regions (cold background, hot nonflaming soil, hot flaming soil and pure flame). This technique has been applied also to observations of forest fires realized from a helicopter at distance of more than 1 Km, revealing that several fire regions can be demarcated, including a fire front in which flame emission makes a large contribution.

A revolutionary new Night Vision System has been designed to help drivers see well beyond their headlights. From luxury automobiles to heavy trucks, Night Vision is helping drivers see better, see further, and react sooner. This paper describes how Night Vision Systems are being used in transportation and their viability for the future. It describes recent improvements to the system currently in the second year of production. It also addresses consumer education and awareness, cost reduction, product reliability, market expansion and future improvements.

This paper describes the newly developed measurement system to record spherical thermograph by using wide-angle scanner, which has single element MCT detector, with panning-tilting mechanism and control system using PC and custom software. We also indicate the examples of evaluating thermal environments in normal living environment using this system.

An algorithm for measuring sea surface temperature (SST) without recourse to the in-situ data for calibration has been proposed. The algorithm which is based on the recorded infrared signal by the satellite sensor is composed of three terms, namely, the surface emission, the up-welling radiance emitted by the atmosphere, and the down-welling atmospheric radiance reflected at the sea surface. This algorithm requires the transmittance values of thermal bands. The angular dependence of the transmittance function was modeled using the MODTRAN code. Radiosonde data were used with the MODTRAN code. The expression of transmittance as a function of zenith view angle was obtained for each channel through regression of the MODTRAN output. The Ocean Color Temperature Scanner (OCTS) data from the Advanced Earth Observation Satellite (ADEOS) were used in this study. The study area covers the seas of the North West of Peninsular Malaysia region. The in-situ data (ship collected SST values) were used for verification of the results. Cloud contaminated pixels were masked out using the standard procedures which have been applied to the Advanced Very High Resolution Radiometer (AVHRR) data. The cloud free pixels at the in-situ sites were extracted for analysis. The OCTS data were then substituted in the proposed algorithm. The appropriate transmittance value for each channel was then assigned in the calculation. Assessment for the accuracy was made by observing the correlation and the rms deviations between the computed and the ship collected values. The results were also compared with the results from OCTS multi- channel sea surface temperature algorithm. The comparison produced high correlation values. The performance of this algorithm is comparable with the established OCTS algorithm. The effect of emissivity on the retrieved SST values was also investigated. SST map was generated and contoured manually.

This article deals with a theoretical substantiation of infrared camera application for pipeline leaks detection. Three various physical principles of temperature anomalies appearance from pipeline leaks are considered. Models of pipeline and leaks thermal contrast are considered. Numerical meanings of temperature differences for three methods are determined. The required basic parameters of the thermal equipment for detection of pipeline leaks are determined.

Some of the work carried out at DETEC on the use of infrared thermography in the architectural restoration field is examined. Three different techniques, pulse thermography (PT), modulated thermography (MT) and pulse phase thermography (PPT) are analyzed through the control of some art treasures such as mosaics and frescoes. In particular, the following artifacts are considered: mosaics covering some external walls of the building of the Faculty of Engineering of Naples, frescoes in the Duomo of Sarno, frescoes in the Cripta SS. Stefani in Vaste (Le), mosaics and frescoes in the Archeological Museum of Naples coming from Pompeii and Ruvo. It is found that the choice of the technique depends on the specific surface to be tested: if only qualitative information about detachments and cracks are needed the pulse thermography is sufficient; if the surface is not very sensitive to temperature rising, the pulse phase thermography can be applied which gives information about the location of the defected zone. If instead, the analysis regards rare art treasures, lockin thermography is the only response.

Thermal behavior in a lightweight building system was studied. The study was performed on a building under construction. Two methods were used. First the building was investigated from the outside and inside with an infrared thermographic camera. Thereafter the thermal behavior of a specific part of the building was evaluated with finite element analysis. The thermal behavior of the building was thereafter evaluated by combining the result of the two different methods. This paper describes the methodology and results of the investigation.

The most reliable method to obtain correct emissivity values for the infrared thermographic systems and applications is to determine the emissivity of the targets to be tested. Although this approach is not possible during in situ applications, samples of the targets can be collected and measured, as in this work, in the laboratory. In the present work, the emissivity values of selected historic building materials were measured at a variety of temperatures, in the 3-5.4 micrometers and 8-12 micrometers regions of the infrared spectrum. Porous stones from the Mediterranean area and marbles, used as historic building materials, were investigated. The examined materials presented different emissivity values, caused by their surface state and microstructure. In addition, the effect of temperature and wavelength on the emissivity values of such historic building materials was also considered.

In this work, infrared thermography is used for detecting the movement of water - moisture in various porous materials in the laboratory, with the intention of validating the examination of real scale material systems in situ. Different materials have been subjected to capillary rise tests and to cycles of evaporation with water under controlled environmental conditions (Relative Humidity and Temperature). Material samples of a reference porous stone, of three basic categories of repair mortars, of consolidated porous stones and of simulating prototype porous materials were examined in lab. Furthermore, systems like historic masonries, were examined in situ, more specifically the Venetian Fortification in Heraklion, Crete and the Medieval Fortifications in Rhodes, undergoing severe alveolation in the aggressive marine atmosphere of the Aegean. Infrared thermography has been shown to be an effective technique for verifying relations between moisture and environmental conditions. Hence, infrared thermography can be used as an evaluation tool for studying the movement of water through porous materials - water absorption and evaporation.

Thermal comfort complaints within work places are one of the leading causes of workforce productivity loss within office environments. Generally, mechanical systems are relied on to provide adequate indoor environments. In many situations, these systems cannot provide suitable work environments due to unacceptable asymmetrical radiant temperature conditions found in exterior zones of building interiors. Public Works and Government Services Canada (PWGSC) has developed methodologies using infrared technology to assist building and office managers in reducing thermal comfort complaints and improve workforce productivity. Detection, verification, remediation and commissioning of solutions are easily and effectively carried out with the assistance of infrared radiometers and proper inspection and analysis procedures. This paper will outline two case studies and detail methodologies used in each case.

Airborne and ground-based thermography surveys have been performed in order to detect moisture and energy related problems in the construction of a public swimming bath building. This paper describes the information potential and the advantages and limitations using a standard IR-camera and traditional inspection methods to gather information for retrofit priorities. The damage conditions indicated in the thermal images are confirmed by field inspections and photographic documentation.

Air leak through the external envelope leads to many inconveniences. Higher consumption of heating energy, draft and possible moisture defects are the result of air infiltration. The automatic ventilation system of the house can also be thrown off balance. The factors mentioned above, together with poor knowledge of airtightness of houses, was reason to start this project airtightness of the buildings in the arctic circle housing fair in Rovaniemi, Finland. The airtightness of houses measured by using the fan pressurization method, according to international standard ISO DIS 9972. The fan pressurization method means that in building caused negative air-pressure from normal approximately 0 Pa up to 50 Pa over the buildings envelope. The air leakage points are searched by using thermal camera. In this project made research differences between materials, structures and production styles. The method and equipment for measuring airtightness are tested and developed in project.

There are no requirements of building air tightness in Finland. Buildings always have thermal bridges and air leak routes, whose impact in decreasing comfort depends on the structures and the way of constructing. Uncontrolled air leaks are cooling the structures and causing draft and, in the long run, defects. These air leaks and thermal bridges can be found only by thermal scanning. In Finland building air tightness has been measured for over 20 years. The procedure includes two stages, in which the target is scanned by a thermal imager. The paper is based on the results of over 200 tests of one-family and detached houses. The air tightness level has improved, but there are still problems in the structural details. The monitoring procedure for therm scanning of buildings should be further developed (there is no generally accepted practice at the moment), as well as air tightness requirements should be created.

In the power generation industry, the efficiency of the plant's heat cycle is crucial in the age of de-regulation. As competition increases, the cost of generating electricity must decrease. To lower costs, nuclear power plants are always looking at ways of recovering lost megawatts. Additionally, plants are striving to maintain high availability, especially during the peak load demands. At the Limerick Generating Station (LGS), the System Manager was tackling both challenges. He determined that Unit #1 Drywell temperatures had been historically higher than Unit #2 Drywell temperatures. The Drywell is a concrete primary containment that houses both the nuclear reactor and recirculation pumps in a Boiling Water Reactor (BWR) plant. A driving force to resolve the higher temperatures was the plant's Technical Specifications which dictate a maximum allowable temperature of 135 degree(s)F in the Drywell. During the summer of 1999 (one of the hottest on record for the East Coast), the temperatures in the Unit #1 Drywell approached the maximum allowed by the Technical Specifications. Exceeding this temperature would require Unit #1 to reduce power during a critical demand period or even shut down. During a peak load condition, the loss of generating capabilities could be extremely costly for the utility. In extreme circumstances, as recent as the winter of 2001 in California, customers could be faced with the potential of roaming brown outs due to the reduced capacity on the electrical grid. Based on the System Manager's experience, the heat source was suspected to be from less than adequate insulated pipes in the Drywell. To determine the condition and status of the insulation, infrared was used to inspect the pipes. The ideal condition is to observe the maximum temperatures when the reactor is at 100% power, but due to the radiological and atmospheric conditions in the Drywell, the inspection would have to be performed immediately after the reactor was shut down for an outage.

The on-line monitoring of temperature permits increasing the campaign and operational stability of the torpedo cars, as well as optimizing the consumption of refractory, thus reducing maintenance costs. It has become an indispensable tool in the productive process at Companhia Siderurgica de Tubarao - CST. This technique was implemented in 1996 with the purpose of following up the evolution of refractory wear in the torpedo cars, using two fixed thermographic cameras (infrared sensors) with a scanning system. The system captures, records and transmits the thermal images of the body surfaces for analysis by computer, besides sounding the alarm when the temperature reaches pre- set values.

This paper summarizes our results on gearbox failure prediction using infrared camera. Experimental data was taken at the Mechanical Diagnostic Test Bed (MDTB) of the Penn State University. It was observed that there is thermal growth before a gearbox failure occurs. One explanation is that friction between gears increases before the gear breaks. A neural net based image-processing tool was developed by Intelligent Automation, Inc. (IAI) to process the infrared images in real-time. Results show that our tool can detect unusual thermal growth five hours before one of the gear teeth was broken.

Thermographers are often at risk when inspecting electrical systems. While electrocution is always a hazard, a far greater danger is injury associated with accidental exposure to an arc flash explosion. Because of the potential for serious injury, and because of new government regulations, more and more companies are now taking steps to prevent arc flash injury and to minimize damage if and when it does occur. In this paper, which would not have been possible without the able assistance of Lowry Eads, global resource for infrared thermography in Dupont, I will discuss why arc flash explosions happen and what damage they can do; I will also show how thermographers can both reduce their risk of being exposed to one and, if they are exposed, their injury from the explosion.

The use of thermography during the last six years has permitted the systematic follow-up of the reduction and control of electrical failures, increasing the operational stability and reliability of equipment and installations. The main factor responsible for the decrease in the failure rate is due to the fact that the maintenance team have been concentrating their efforts only in the critical points, previously detected through thermographic inspections. This paper presents the actual behavior of the failures characteristic curves along the time in all the productive units of Companhia Siderurgica Tubarao - CST.

The campus of a comprehensive, residential university is in many respects a small city unto itself. All the amenities and services one would expect in a typical community are readily available on a college campus, including residences, athletic and dining facilities, libraries, and stores. A large campus, therefore, requires a reliable energy plant to provide steam, hot water, chilled water, and electricity. James Madison University supports two power plants: a vintage steam plant and a modern resource recovery facility comprising two solid-waste incinerators and two gas-fired units for steam generation, three steam-driven absorption- chilling units, and a single steam-driven generator for peak electricity production. Infrared imaging, as a teaching tool, was introduced in the Program of Integrated Science and Technology at James Madison University in 1997. The Infrared Development and Thermal Testing Laboratory was established at the university later in 1997 with government and industry support, and it is presently equipped with infrared imagers and scanners, single-point detectors, and data-acquisition systems. A study was conducted between 1998 and 1999 to test the economic feasibility of implementing an IR-based predictive maintenance program in the university steam plant. This paper describes the opportunities created at James Madison University to develop IR-based predictive maintenance programs that enhance the operation of the university energy plants; to establish IR-related research and development activities that support government and industry activities; and to enhance a science- and technology-based curriculum by way of unique, IR-based laboratory experiences and demonstrations.

Portable thermal imagers are being utilized with great success in many new and emerging applications, and the law enforcement field in particular is benefiting from thermal imagery. It is quickly becoming common practice for enforcement agencies to apply night-vision technology in such activities as search and rescue, surveillance and stakeout, and suspect pursuit. Thermal cameras, however, do not typically provide an intrinsic means for video recording or for visible imaging. Such capabilities could significantly expand and improve the uses of thermal imaging by law enforcement personnel. For example, surveying the scene of a crime or traffic accident with a thermal sensor offers potential for revealing and documenting clues that otherwise go unnoticed. This paper presents a system that integrates an IR micro-camera with a visible camcorder. The system can display and record live visible and thermal imagery and also capture single-frame snapshots on removable media. This paper also explores the utility of such an integrated camera in various law enforcement scenarios.

This manuscript is written in memory of a fellow thermographer who tragically lost his life in an automobile accident during the July 4th weekend in the year 2000. Craig Bidleman, a General Motors (GM) Level III Infrared Thermographer, was killed along with his wife Tina, daughter Dana and mother Florence. His 7-year old son Brandon survived the crash. The visible light and infrared images of Craig included in the main body of the presentation were taken from archives accumulated during the five years he worked in the planned maintenance predictive technology arena. Highlights of Craig's professional career in thermography and his impact on GM and his co-workers are emphasized. Craig's death brought an outpouring of disbelief and sadness from not only the thermographic community but outside as well. The most poignant memorial of all was expressed in a letter, written by fellow thermographer L.J. Broeker, entitled 'In Memory of Craig', which summarizes the feelings many people had when the news of Craig's death was revealed.

The paper summarizes the authors' experience in conducting IR thermographic surveys of 60-200 m tall smokestacks typical of Russian power plants and industrial enterprises.

The Optical Technology Division (OTD) at the National Institute of Standards and Technology (NIST) maintains the thermodynamic temperature scale above the silver freezing point using spectral radiance ratios according to the International Temperature Scale of 1990 (ITS-90). Radiance temperature calibration services are performed in the OTD, and NIST's calibration services support industry, government agencies, national standards laboratories, pyrometer and blackbody manufacturers, universities, and U.S. military service calibration laboratories. In addition, the OTD also offers a four day Short Course on Temperature Measurement by Radiation Thermometry every year that extensively covers many aspects of radiation thermometry. Routine intercomparisons of the thermodynamic temperature scale are done with other national measurement laboratories for international verification of the accuracy of the issued calibrations. We describe research into alternatives to the ITS-90: the use of absolute detector standards to directly measure the temperature of a high temperature blackbody.

Infrared imaging, sensing and measuring devices and infrared lasers require predictable and accurate sources of infrared radiation as a basis for accurate calibration. This paper discusses the theory governing the design and construction of such devices (Blackbody Sources), and references the theoretical laws relating to infrared radiation, absorption and reflection.

An IR camera responds to infrared radiant energy over a waveband determined by the camera optics and detector. Most cameras operate in either the 3 to 5 micrometers or 8 to 12 micrometers wavebands as they represent good atmospheric windows. Temperature measurement using these cameras is performed within the camera, which will correct for target emissivity and background temperatures. The algorithm that does this makes a key assumption: the target is a graybody source (constant emissivity over the waveband of the IR camera). To effect this calculation, modern infrared (IR) cameras are calibrated using blackbody sources. The calibration data set is stored in the camera firmware as a lookup table. To be accurate, blackbody sources must be graybodies with emissivities very close to one. The fact that there are no perfect blackbodies can be overcome as long as the emissivity is constant with wavelength. Spectroradiometric calibration of blackbody sources is the best way to ensure the radiant energy emanating from the source follows Planck's law over the waveband of the IR camera being calibrated (another way of saying graybody). At FLIR Systems, Inc. we used a CI Systems SR-5000 spectroradiometer to spectrally characterize 20 blackbody sources of various manufacturer and type.

According to the international standards ISO 9001-9004 and EN 45001-45003 the industrial plants and the accreditation laboratories that implemented the quality systems according to these standards are required to evaluate an uncertainty of measurements. Manufacturers of thermal cameras do not offer any data that could enable estimation of measurement uncertainty of these imagers. Difficulties in determining the measurement uncertainty is an important limitation of thermal cameras for applications in the industrial plants and the cooperating accreditation laboratories that have implemented these quality systems. A set of parameters for characterization of commercial thermal cameras, a measuring set, some results of testing of these cameras, a mathematical model of uncertainty, and a software that enables quick calculation of uncertainty of temperature measurements with thermal cameras are presented in this paper.

In various applications of Infrared (IR) Thermography there is need for measuring true surface temperatures. Modern radiometric IR cameras are equipped with sophisticated tools like internal temperature sensors or internal temperature references to provide stabilized temperature read-outs and can guarantee a specified accuracy. But these manufacturer's accuracy specifications are only valid for known objects and under controlled laboratory conditions. In field use there are external effects such as unknown object emissivity, reflections or absorption that can be compensated by means of mathematical models. These factors usually have a significant influence on the results thus making it difficult for the user to estimate the real accuracy of the measurement. This paper introduces a computer tool where the thermographic measurement situation has been implemented in an MS Excel spreadsheet file. The user can vary the measurement parameters in the spreadsheet very easily using graphic controls called sliders. In a mixed numeric and graphical presentation the user can get a feel for the influence of a certain parameter in a specific situation and the model provides a good estimate of the measurement accuracy under realistic conditions.

Infrared thermometry in the real world is a very demanding method of temperature measurement occurring in a wide variety of applications covering a wide range of industries. Whether measuring target spots, lines or images, end users demand accurate temperature data to the same degree as they would by measuring with traditional contact methods. Designing an accurate non-contact measurement instrument requires paying attention to the entire measurement system from object to the optical system to the detector to the electronics as well as the target environment. Among the many challenges involved is the task of establishing universally accepted traceability standards for low temperature blackbody sources using radiation, rather than contact methods, as transfer devices. Such standards have been recently introduced and, if finally accepted by all National Standards Institutes and used by the IR instrument manufacturers, will go a long way to improve the temperature measurement accuracy of all infrared measurement instruments. For many industrial users, this proof of absolute accuracy is a prerequisite for the acceptance of infrared thermometry as a useful and serious temperature measurement method.

An experimental facility is presented, which allows calibration and detailed investigation of infrared camera systems. Various blackbodies operating in the temperature range from -60 degree(s)C up to 3000 degree(s)C serve as standard radiation sources, enabling calibration of camera systems in a wide temperature and spectral range with highest accuracy. Quantitative results and precise long-term investigations, especially in detecting climatic trends, require accurate traceability to the International Temperature Scale of 1990 (ITS-90). For the used blackbodies the traceability to ITS- 90 is either realized by standard platinum resistance thermometers (in the temperature range below 962 degree(s)C) or by absolute and relative radiometry (in the temperature range above 962 degree(s)C). This traceability is fundamental for implementation of quality assurance systems and realization of different standardizations, for example according ISO 9000. For investigation of the angular and the temperature resolution our set-up enables minimum resolvable (MRTD) and minimum detectable temperature difference (MDTD) measurements in the various temperature ranges. A collimator system may be used to image the MRTD and MDTD targets to infinity. As internal calibration of infrared camera systems critically depends on the temperature of the surrounding, the calibration and investigation of the cameras is performed in a climate box, which allows a detailed controlling of the environmental parameters like humidity and temperature. Experimental results obtained for different camera systems are presented and discussed.

An application of infrared radiometer or IR camera has been widely spread in many industries for these twenty years, because of its convenience to use, wide measuring range by remote sensing, and visual survey due to thermal image. In this IR method it is very useful to detect invisible surface and internal flaws. Conventional IR makers are accustomed to use NETD as the resolution characteristics of IR camera, but general customers using IR camera cannot evaluate the minimum detectable size of measuring object, if they cannot evaluate MRTD. The study of the quantitative evaluation to clarify the relation between NETD and MRTD is very little. This paper represents evaluation methods of NETD and MRTD, and their quantitative relation by using collimator FLIR testing.

This published standard describes consensus test methods for radiation thermometers of the single waveband type that are important in characterizing some of their parameters related to temperature measurement. It is intended to provide methods by which both manufacturers and end users may make tests to establish the validity of instrument readings and to serve as performance criteria for instrument evaluation and selection. This paper will review the standard and consider some examples of application of the test methods to several types of devices.

The Savannah River Technology Center (SRTC) is currently calibrating the Multispectral Thermal Imager (MTI) satellite sponsored by the Department of Energy. The MTI imager is a research and development project with 15 wavebands in the visible, near-infrared, short-wave infrared, mid-wave infrared and long-wave infrared spectral regions. A plethora of targets with known temperatures such as power plant heated lakes, volcano lava vents, desert playas and aluminized Mylar tarps are being used in the validation of the five thermal bands of the MTI satellite. SRTC efforts in the production of cold targets with aluminized Mylar tarps will be described. Visible and thermal imagery and wavelength dependent radiance measurements of the calibration targets will be presented.

A two-dimensional imaging spectrograph, developed for non- intrusive temperature measurements in flames, has been characterized using a pressure-controlled sodium heat pipe blackbody (Na-HPBB). The spectrograph contains a two- dimensional PtSi CCD array and provides spatial information in one dimension and spectral information in the other dimension. The usable range of the spectrograph, which images a line approximately 35 mm in length, covers the region from 2.5 micrometers to 5.0 micrometers . Using the stable and uniform Na-HPBB, the spectrograph was calibrated for absolute spectral radiance by employing Planck's Law. These measurements show that the spectrograph uniformity is within 0.25% (k equals 2), and provide calibration constants that can be applied to future measurements. The results presented here will enable the spectrograph to be used to measure the emission characteristics of high temperature surfaces, gases, and particles, and as a transfer detector to calibrate other secondary sources.

A fiber optic two-color pyrometer has been developed at the Institute of Heat Transfer and Air Conditioning at RWTH Aachen to measure temperatures at surfaces with low emissivities with a high time and space resolution. A fused silica fiber is used to transmit the radiation to the pyrometer from measuring positions with limited optical access. The two-color principle allows accurate measurements of absolute temperatures of surfaces with unknown emissivities if the assumption of a gray body behavior at the measurement wavelengths is valid. The minimum temperature which can be measured with the pyrometer is limited due to the small radiation energy at low temperatures given by Planck's law, the emissivity of the body and the size of measurement area. At present temperatures of low emissivity metallic surfaces with sizes of 0.4 mm can be measured down to 250 degree(s)C. A new application to measure temperatures during high speed turning required a time resolution above the maximum of 2 microsecond(s) . To enhance the time resolution of the pyrometer the electronics was modified and a 30 MHz data acquisition board has been applied to the system. With this configuration a nanosecond time resolution is possible but the minimum measurable temperature increases. Different aspects for the limitation of the time resolution will be discussed. A new set-up with a nanosecond spark-flashlight will be described for the test of the transient response of the pyrometer and some test measurements will be presented.

The concept of basing a temperature scale on a wavelength standard was introduced by Gebbie almost 30 years ago, in a proposal to use Fourier-transform spectroscopy to measure the emission from blackbody sources operated at a series of different temperatures. At the National Research Council of Canada, we have embarked on a project to investigate the feasibility of this idea. Experimental and theoretical results will be shown describing an interpolation technique for obtaining temperature information for intermediate settings of the source, when the highest and lowest spectra are assumed fixed and known. The ratio technique which combines spectra three at a time is then considered as a candidate for determining a self-consistent solution which can calculate the temperatures of all of the data, thus eliminating the requirement for the two calibration points. Work with real and simulated data is presented to explore some of the difficulties faced when attempting to determine absolute thermodynamic temperature in this way.

The overwhelming introduction of magnetic devices and other alternative therapies into the health care market prompts the need for objective evaluation of these techniques through the use of infrared thermal imaging. Many of these therapies are reported to promote the stimulation of blood flow or the relief of pain conditions. Infrared imaging is an efficient tool to assess such changes in the physiological state. Therefore, a thermal imager can help document and substantiate whether these therapies are in fact providing an effective change to the local circulation. Thermal images may also indicate whether the change is temporary or sustained. As a specific case example, preliminary findings will be presented concerning the use of magnets and the effect they have on peripheral circulation. This will include a discussion of the recommended protocols for this type of infrared testing. This test model can be applied to the evaluation of other devices and therapeutic procedures which are reputed to affect circulation such as electro acupuncture, orthopedic footwear and topical ointments designed to relieve pain or inflammation.

Experimental results disclosing temperature change of human skin affected by various unnatural factors are presented in detail. Thermograms are obtained with the IR thermograph containing high performance InAs CID FPA-based photosensitive unit. Using logarithmic scale of time, evolution of skin temperature after moistening, spirit sponging, and olive oil lubrication is investigated. A comparative analysis of the resulting effects of treatments including alpha-hydroxy acid, cosmetic regenerating cream, spirit, and water, is made. Quantitative distinctions between skin regions characterized by ordinary, and depleted blood supply, including areas located directly above surface main vessels, are revealed. Strongly logarithmic time- dependence of a skin temperature is discovered when the skin is cooled down after its preliminary heating with a hot wax. Non-monotonic change of a local temperature during electrically active procedure is described. Low level light therapy equipment is also applied. A special role of the temperature of nose is discussed.

The left-right thermal asymmetry of human bodies is statistically analyzed on a few selected body parts. The three statistical parameters, including signal-to-noise ratio, Z-criterion and D-criterion, are recommended to verify a grade of asymmetry in the case of pathologies. The variability of these parameters attributed to healthy persons is discussed.

We have assessed the thermal camera to complement the clinical odontology with the clinical assistance of acupuncture. Relevant cases of study were those of patients with facial pain. This work has registered the temperatures of the microsystem of the lobe of the outer ear. The recordings were made before, during and after removing the needles. Measurements of patients' temperatures were made very two minutes for 20 minutes, and a gradual increase of temperature was observed. The thermal camera allowed to register maps (thermography) that show an area affected with pain. After thermograms were performed to odontology patients treated with acupuncture, we were able to compare the temperature distribution maps and we found that they were quasi repetitive in the same zones in several patients for a specific illness. We made this technique available to different patients with lack of good irrigation on face and neck with the aim to establish patterns.

The proposal to use active thermography in medical diagnostics is promising in some applications concerning investigation of directly accessible parts of the human body. The combination of dynamic thermograms with thermal models of investigated structures gives attractive possibility to make internal structure reconstruction basing on different thermal properties of biological tissues. Measurements of temperature distribution synchronized with external light excitation allow registration of dynamic changes of local temperature dependent on heat exchange conditions. Preliminary results of active thermography applications in medicine are discussed. For skin and under- skin tissues an equivalent thermal model may be determined. For the assumed model its effective parameters may be reconstructed basing on the results of transient thermal processes. For known thermal diffusivity and conductivity of specific tissues the local thickness of a two or three layer structure may be calculated. Results of some medical cases as well as reference data of in vivo study on animals are presented. The method was also applied to evaluate the state of the human heart during the open chest cardio-surgical interventions. Reference studies of evoked heart infarct in pigs are referred, too. We see the proposed new in medical applications technique as a promising diagnostic tool. It is a fully non-invasive, clean, handy, fast and affordable method giving not only qualitative view of investigated surfaces but also an objective quantitative measurement result, accurate enough for many applications including fast screening of affected tissues.

A new diagnosis method based on the pulse heating thermographic NDT was proposed for the incipient caries of human teeth. Experimental study was made on the applicability of the proposed method to the quantitative evaluation of location and shape of the incipient caries as well as the quantitative diagnosis of the degree of incipient caries. The incipient caries were artificially introduced to the extracted human teeth in various severities. Impulse heat flux by the xenon flash lamp was applied to the surface of the tooth and sequential thermal images were taken by the high-speed infrared thermography. It was found that the caries were clearly identified as the localized high temperature region in the sequential thermal images. Coefficients of the temperature descent were obtained from sequential thermal images. It was found that the degree of the demineralization, i.e. the degree of incipient caries was evaluated from temperature descent coefficients.

The use of pulsed thermography as an NDE solution for manufacturing and in-service applications has increased dramatically in the past five years, enabled by advances in IR camera and computer technology. However, the basic approaches to analysis and processing of pulsed thermographic data have remained largely unchanged. These methods include image averaging, subtraction, division, slope calculation and contrast methods (e.g. peak contrast and peak slope time mapping). We have developed an alternative approach to analysis of pulsed thermographic data, based on developing a parametric equation for the time history of each pixel. The resulting synthetic image provides increased spatial and temporal resolution, and significantly extends the range of defect depths and sample configurations to which pulsed thermography can be applied. In addition, our approach reduces the amount of data that must be manipulated and stored, so that an entire array of image sequences from a large structure can be processed simultaneously.

The paper presents the method for determining the subsurface defects in material by means of active thermography and 3D numerical non-stationary heat conduction model. Determination of the subsurface defects by Thermal Non- Destructive Testing means the description of the defects dimensions and its location. The method is tested on the samples made of metal and composite materials having known subsurface defects. The results obtained are discussed from the point of view of influence of the neighboring defects on the current contrast curve and possibilities of predicting the behavior of the composite material by estimation of their thermal properties. The software developed enables the calculation of the temperature distribution through the sample versus time and location of the defect by means of inverse method involving experimentally obtained thermogram.

The thermal line scan technique has been shown to be an effective technique for rapid inspection of aerospace specimens. Past efforts have focused on thermal measurements far behind the line source where the heat flow normal to the surface is negligible. This paper focuses on measurements closer to the line source to enable the measurement of the thermal diffusivity in the surface normal direction. This measurement also enables an independent characterization of the thermal diffusivity in the direction of motion of the thermal line source. An analytical solution is given for a line source moving with constant velocity across an anisotropic plane. A nonlinear least squares fitting routine is used to reduce the temporal response of a specimen to images of the thermal diffusivity in both the directions normal to the surface and parallel to the motion of the line source. Measurements are presented on specimens with known variations in effective diffusivity. Measurements on these specimens allow a comparison of this technique to more conventional techniques for diffusivity measurement.

The paper aims to illustrate three advantages of infrared thermography as a non-destructive, non-contact and real time technique (a) to detect the occurrence of intrinsic dissipation localization, (b) to observe the progressive damage processes and mechanisms of tennis string failure, and (c) to determine the optimal tension for each type of string. Experimental results evidence a limit of acceptable damage beyond which strings will fail due to the coalescence of defects and/or weakness zones. In addition, owing to the thermomechanical coupling, this technique provides a simple means for evaluating the wear resistance of strings of interest for skilled tennis players who impart on the ball a great amount of spin combined with a high stroke velocity.

Photothermal methods have proved to be applicable to the detecting of vertical surface cracks. The advantage over crack detection via ultrasonics or magnetic particle testing lies in the fact that the photothermal detection, from its concept, is contactless and can be highly automated using digital image processing techniques. One disadvantage is that the scanning rate is presently far below the level desired for on-line quality control in the steel producing industry. The large degrees of freedom (parameters) in photothermal detection, such as impinging power or temporal and spatial characteristics of the modulation of the heat source, make it difficult to find an optimum in this method. This paper presents a fundamental research project which was started for theoretical investigation of the photothermal detection technique to enable the identification of optimum configuration and parameters. Finite element simulations and analytical solutions were employed for better understanding of the influence of the free parameters on the heat flow and the observable temperature signal around cracks. This paper concentrates especially on results found for impulse thermography and presents a model which can be used for optimizing speed and detectivity of the method.

Pulse heating thermographic NDT technique was developed for the detection of latent blisters in the corrosion protective coating on oil storage tanks employed for petroleum stockpiling in Japan. Experimental studies were made on the applicability of the proposed NDT method to the quantitative identification of the subsurface latent blisters in the coating. Pulse heat flux by the xenon flush lamp was applied to the surface of the corrosion protective coating and sequential thermal images were taken by the high-speed infrared thermography. It was found that the blisters were clearly identified as the localized high temperature region in the sequential thermal images.

This paper aims to illustrate the advantages of Lock-In Thermography (LIT) as a non-destructive, real time and non- contact technique to analyze and to locate thermo-mechanical mechanisms in materials and structures. Due to the first and second principles of thermodynamics, there is a relationship between temperature and mechanical behavior laws. LIT is classically used to measure linear thermo-elastic effect to evaluate stresses in structures under periodic, random or transient loading. The new digital processing D-MODE presented allows extracting non-linear coupled thermo-mechanical effects (dissipated energy) cycle by cycle during a fatigue test on specimens and on real structures. This quantity much smaller than thermo-elastic source needs a high sensitive thermal imaging camera and a dedicated algorithm to separate dissipated energy from thermo-elastic source. On the other hand, it has been known for a long time that there is a correlation between plasticity in materials and the appearance of heat dissipation. More recently, it was shown there is a clear relationship between fatigue limit and occurrence of dissipated energy. We propose to improve these two methods by using LIT instead of temperature rise measurement to predict crack occurrence in real structures. At last we present some industrial applications in automotive and aircraft industries.

Pulsed phases thermography (PPT) is a well-known processing method of non-destructive testing (NDT) by infrared thermography. This method is based on the frequency analysis of the images obtained from pulsed infrared thermography. The Fast Fourier Transform (FFT) is generally used for this technique. Such a method faces important time aliasing problems. Particularly important when slow infrared cameras are used and also in case of inspection of high thermal conductivity material like aluminum. Moreover, the oddness of the phase function, which is often the interesting part of the frequency response of the experiment increases dramatically this problem.

Elastic waves sent into the component propagate inside the sample until they are converted into heat. A defect causes locally enhanced losses and consequently selective heating up. Therefore amplitude modulation of the injected elastic wave turns a defect into a thermal wave transmitter whose signal is detected at the surface by lock-in thermography synchronized to the frequency of amplitude modulation. This way ultrasound lock-in thermography allows for selective defect detection which enhances the probability of defect detection in the presence of complicated intact structures. Measurements were performed on various kinds of mechanical joints. The results of our feasibility study indicate that both optical (OLT) and ultrasound exited lock-in thermography (ULT) are reliable tools for the rapid identification of damaged riveted structures. We demonstrate that one can locate a screw joint or a riveting which provide only a reduced stress. Investigations on airplane components were performed which confirmed the applicability of lock-in thermography for remote maintenance inspection within a few minutes.

Ultrasound Phase Thermography (UPT) is a non-destructive technique derived from Ultrasound Lock-In Thermography (ULT) which was established a few years ago. UPT provides defect selective imaging using thermal waves generated by elastic waves. The use of short ultrasound bursts instead of sinusoidal signals for excitation allows for faster measurements and better reproducibility as compared to ULT. However, the advantages of phase images are the same: recognition of defect depth and suppression of temperature gradients. Application of UPT to typical defects of aircraft materials and components provide specific information on their nature.

Aerospace structures are subjected to variable loads over long periods with rapid changes of conditions (e.g. humidity, temperature). Therefore the materials and components made out of them may suffer from aging and deterioration, especially since the weight of such structures is an important quantity. On the other hand, any failure of a component may cause costs that exceed by many orders of magnitude the cost of the component itself. On this background it is important to identify defects reliably and early enough during production or maintenance inspections in order to avoid catastrophic failure. This is the general and important task of nondestructive evaluation. We present a method where thermal effects are selectively activated in defects so that defects reveal themselves selectively even in the presence of complicated intact features. The mechanism involved is local friction or hysteresis which turns a variably loaded defect into a heat source which is identified by thermography. Loading is achieved by an elastic wave or oscillation with a suitable time dependence. The method is presented together with results obtained on aerospace structures.

The purpose of this paper is to describe a new method for thermal nondestructive evaluation. This method uses a synchronized electronic shutter system (SESS) to remove the heat lamp's influence on the thermal data during and after flash heating. There are two main concerns when using flash heating. The first concern is during the flash when the photons are reflected back into the camera. This tends to saturate the detectors and potentially introduces unknown and uncorrectable errors when curve fitting the data to a model. To address this, an electronically controlled shutter was placed over the infrared camera lens. Before firing the flash lamps, the shutter is opened to acquire the necessary background data for offset calibration. During flash heating, the shutter is closed to prevent the photons from the high intensity flash from saturating the camera's detectors. The second concern is after the flash heating where the lamps radiate heat after firing. This residual cooling introduces an unwanted transient thermal response into the data. To remove this residual effect, a shutter was placed over the flash lamps to block the infrared heat radiating from the flash head after heating. This helped to remove the transient contribution of the flash. The flash lamp shutters were synchronized electronically with the camera shutter. Results are given comparing the use of the thermal inspection with and without the shutter system.

Composite materials are prone to various damages, particularly if used for aeronautic fuselage components. These parts are increasingly used for civil and military aircraft. Internal defects, invisible on the surface, are detectable by means of different NDT methods, having individual advantages and drawbacks. Here, potentialities of IR Thermography are explored to detect and characterize delaminations and internal cracks on an aircraft door made of composite materials. The non-planar surface of the component has a varying thickness. A detailed study of the defect maps given by different data reduction algorithms is oriented to the design of a fast procedure suitable for an in situ application. In particular, the critical parts of the doors are tested on both sides in reflection and transparent mode. The reliability and quality of results is evaluated comparing thermography with data obtained by different methods as Ultrasounds and Mechanical Impedance. Experimental results show great effectiveness of thermography especially using pulsed techniques and phase analysis.

We describe progress in thermosonic crack detection. In this technique, a short single pulse of ultrasound is used to cause cracks to heat up and become visible in the infrared. A low frequency (say 10's of kHz) ultrasonic transducer infuses the sample with sound. Where cracks, disbonds, delaminations or other defects are present, the sound field causes the defect to heat locally. The technique is applicable to large and irregularly shaped objects. We present illustrative applications of this technology to aerospace, and automotive inspections.

Wall thinning due to corrosion in utility boiler waterwall tubing is a significant operational concern for boiler operators. Historically, conventional ultrasonics has been used for inspection of these tubes. Unfortunately, ultrasonic inspection is very manpower intense and slow. Therefore, thickness measurements are typically taken over a relatively small percentage of the total boiler wall and statistical analysis is used to determine the overall condition of the boiler tubing. Other inspection techniques, such as electromagnetic acoustic transducer (EMAT), have recently been evaluated, however they provide only a qualitative evaluation - identifying areas or spots where corrosion has significantly reduced the wall thickness. NASA Langley Research Center, in cooperation with ThermTech Services, has developed a thermal NDE technique designed to quantitatively measure the wall thickness and thus determine the amount of material thinning present in steel boiler tubing. The technique involves the movement of a thermal line source across the outer surface of the tubing followed by an infrared imager at a fixed distance behind the line source. Quantitative images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the inspection speed and accuracy for large structures such as boiler waterwalls.

The analysis of complex probe geometry heating and cooling was done with the aim to find the temperature distribution inside the probe versus time. An infrared thermography was used to measure surface temperatures while temperatures in control points inside the probe were measured with thermocouples. The results obtained by numerical model based on the control volume approach, where thermographic measurements were the input parameters, show good mutual accordance with those measured by thermocouple at referent points of the probe. Applied on heat treatment of metals, this method provides a possibility to monitor temperature change for each single point inside the probe in a way which will guarantee that the desired microstructure is obtained. The local and average heat transfer coefficients have also been calculated by means of a numerical model. Based on the data, it is possible to simulate similar processes without providing measurements for all possible setups of the furnace parameters. Additional optimization is possible when experimental rig for real time calculation of temperature fields (measurement and calculation at the same time) will be realized.

This paper describes a neural network approach to detecting solder defects on printed circuit boards when using thermal signatures. Solder defects such as open and insufficient solder was investigated. A multilayer neural network with multiple inputs and a single output was utilized. A back- propagation algorithm was utilized within the network. Computer mouse printed circuit boards with known introduced solder defects and amounts of solder were used for experiments. Thermal images were acquired as the boards were powered up. A Visual Basic program was written to retrieve temperature data from an encoded image file format. Afterwards, MATLAB neural network routines were applied to analyze the data. The neural network was able to diagnose solder defects on two of five resistors with 91.1% accuracy, and on three of five resistors with 61.1% accuracy.

The definition of the thermal dynamics of a structure-work of cultural interest is important both from the microclimatic point of view and from the structural one. Elastic and plastic deformations, due to phenomena of heat exchange, influence, in a significant way, the mechanical behavior of the structure. Dealing with objects exposed to open air, one of the main sources of heat radiation is, obviously, the sun. Consequently, it is significant to evaluate the importance that solar radiation has in the global heating dynamics of the structure. Therefore, while studying the system Marcus Aurelius- Capitolium square, it was decided to support the investigations in situ (carried out by using thermovision and thermocouples) with the realization, on computer, of a system that could define the theoretical relationship existing between solar dynamics and the bronze monument. Correlation between information deduced from such a model and data obtained in situ, gave useful results and constituted a significant instrument for the analysis of the concrete thermal model of the investigated structure. The opportunity to deepen and improve such an experience arose when the Soprintendenza per i Beni Architettonici ed Ambientali di Firenze e Pistoia asked for a contribution to the studies and investigations aimed to define the thermal model of the Dome of Santa Maria del Fiore.

A suite consisting of an infrared sensor, optical sensors and a video camera are prepared for launch by a group of students at University of Virginia (UVA) and James Madison University (JMU). The sensors are a first step in the development of a Gas Filter Correlation Radiometer (GFCR) that will detect stratospheric methane (CH₄) when flown on sub-orbital sounding rockets and/or from the hypersonic X-34 reusable launch vehicle. The current payload has a threefold purpose: (a) to provide space heritage to a thermoelectrically cooled mercury cadmium telluride sensor, (b) to demonstrate methods for correlating the IR reading of the sensor with ground topography, and (c) to flight test all the payload components that will become part of the sub- orbital methane GFCR sensor. Once completed the system will serve as host to other undergraduate research design projects that require space environment, microgravity, or remote sensing capabilities. The payload components have been received and tested, and the supporting structure has been designed and built. Data from previous rocket flights was used to analyze the environmental strains placed on the experiment and components. Payload components are being integrated and tested as a system to ensure functionality in the flight environment. This includes thermal testing for individual components, vibration testing from individual components and overall payload, and load testing of the external structure. Launch is scheduled for Spring 2001.

The purpose of this research is to develop a system that can accurately quantify carbon monoxide (CO) concentrations over very small regions in the troposphere by using a gas filter correlation radiometric (GFCR) system and utilizing the Moon as the infrared source. GFCR is an established method of remotely sensing the concentrations of atmospheric gases. The measurement is made by correlating a narrow-band infrared image of the source, taken through a gas filter cell (containing a known pressure of the gas), to an image taken through an evacuated filter cell. Although the GFCR technology was originally developed for use on satellites looking down at the Earth, this study takes the measurement from the Earth looking up at the Moon. An ancillary purpose of this study is to image the surface of the Moon over a narrow wave band (approximately 2102-2183 cm^-1) on a large format focal plane array, and to attempt to characterize the surface as an infrared emitter.

Bonding is a critical process often employed in the manufacture of electronic components. The temperatures associated with the bonding process affect the quality and performance of a final product. This temperature can be observed using a two-color fiber optic measurement system which monitors temperatures during the manufacturing process by gathering and analyzing infrared radiation emitted from a target device. The system described in this document is intended for use in process control of component fabrication; however, it is applicable to a variety of fields both within and beyond the realm of manufacturing. This is verified by way of post-design experimentation involving solar sail material used commonly in aerospace construction.

New low cost uncooled infrared devices (such as PalmIR 250 (Raytheon), Thermacam 540 (FLIR), Indigo...) are giving new possibilities for small or medium sized companies. Even if each pixel of the temperature image is noisy, even if the global signal is randomly shifted due to the technology of ferromagnetic or bolometric detectors and even the characteristics of the detectors of the matrix are not uniform, it is possible to use these cameras for Non- Destructive Evaluation (NDE). The main idea is to use the video output data and associate to such devices recording and real time systems with adapted processing methods, in order to set out a very cheap NDE system. We present, in this framework, some processing methods based on the estimation of thermophysical parameters variations around a nominal value by an asymptotic gradient development. Theoretical arguments will illustrate this purpose and several examples in various industrial domains will be shown: estimation of thickness variations of a PVC plate; estimation of density variation of ceramic plates; estimation of thermal conductivity variation of textile layers.

Patients diagnosed with periodonthopathies were subjected to thermographic study in order to analyze blood circulation in the periodontal region and pattern of temperature changes in the gingival crevice. The aim of the study was to assess the influence of insulin-dependent diabetes mellitus (IDDM) on the status of blood vessels in the periodontal region in children and adolescents. Clinical status of the periodontal region was assessed with CPITN (Community Periodontal Index of Treatment Needs). Thermographic patterns were taken in the vicinity of teeth 11 and 21 at some distance from the gingival margin and frenulum of the upper lip, which permitted elimination of a possible influence of other factors on the parameters studied. The thermographic measurements were a few times repeated for each patient and made before and 1, 2, 3, and 4 minutes after cooling of a selected surface of gingival mucosa. Interpretation of the thermographic patterns was performed taking into account the minimum and maximum temperatures: T min and T max, and Tx - the weighted mean for the left and right sides. Preliminary observations revealed a difference between the data obtained in the group with IDDM and the control group. The results suggest the suitability of the thermographic study for assessment of vascular changes in IDDM patients.

Local and mean convective heat transfer from a rotating TGV brake disc model in the actual environment and submitted to an air flow parallel to the disc surface is studied experimentally in this paper. The experimental technique is based on the use of a heated thermally thick disc combined with the technique of temperature measurement by infrared thermography. The local convective heat transfer coefficient from the disc surface is identified by solving the steady state heat equation by finite difference method using the experimental temperature distribution as boundary conditions. These tests were carried out for rotational speed (omega) between 325 and 2000 rpm (rotational Reynolds number Re between 88500 and 545000) so as to obtain laminar and turbulent flow on the disc, and for air flow velocity U ranging between 0 and 12 m s^-1 (air flow Reynolds number Re₀ between 0 and 153000).

Textile manufacture occupies a prominence place in the national economy. By virtue of its importance researches have been made on the development of new materials, equipment and methods used in the production process. The cutting of textiles starts in the basic stage, to be followed within the process of the making of clothes and other articles. In the hot cutting of fabric, one of the variables of great importance in the control of the process is the contact temperature between the tool and the fabric. The work presents a technique for the measurement of the temperature based on the processing of infrared images. For this a system was developed composed of an infrared camera, a framegrabber PC board and software that analyzes the punctual temperature in the cut area enabling the operator to achieve the necessary control of the other variables involved in the process.

Are one of the pathologies more frequent in infant surgery - intra-abdominal, inguinal or ectopic. With actual methods of diagnosis some inguinal and none of the abdominal are detectable. Change of temperature is one of the elements to explain the detection in the maturity and development of the testes. Hormonal stimuli are used to obtain the increase in the development and descent of the testis. In this research we will test if thermography can be an effective technology for the diagnosis in the localization and morphology testicular. Another important feature will be to test if thermography may detect some of the stimulus testis with induction hormonal.

The global economy of the 21st Century will place continued pressure on newer and better products. Products will have tighter and tighter specifications to meet the demand of the sophisticated consumer. For industry this will mean that the development department will have to update old products or more likely, create entirely new products to keep up with this demand. For the manufacturing and process plant this will mean a product with tighter tolerances, better quality and uniformity, while increasing machine and plant efficiency. To accomplish this, facilities will place tighter specifications on the manufacturing process, which will in turn, place greater demands for additional and improved process monitoring and control. Process Monitoring and Control Instrumentation has been a growth industry and will only continue to expand well into the 21st Century. One technology that is only now beginning to penetrate this area is Infrared Thermography.

Calibration procedures for infrared thermometers and thermal imaging systems require radiation sources of precisely known radiation properties. In the physical absence of an ideal Planck's radiator, the German Committee VDI/VDE-GMA FA 2.51, 'Applied Radiation Thermometry', agreed upon desirable specifications and limiting parameters for a blackbody calibration source with a temperature range from -20 degree(s)C to +350 degree(s)C, a spectral range from 2 to 15 microns, an emissivity greater than 0.999 and a useful source aperture of 60 mm, among others. As a result of the subsequent design and development performed with the support of the laboratory '7.31 Thermometry' of the German national institute of natural and engineering sciences (PTB), the Mester ME20 Blackbody Calibration Source is presented. The ME20 meets or exceeds all of the specifications formulated by the VDI/VDE committee.

Sonic IR was evaluated as an NDE technique at LLNL using a commercial ThermoSoniX system from Indigo Systems Corp. The main effort was to detect small cracks in aluminum oxide, a dense stiff ceramic. Test coupons were made containing 0.2- mm cracks by surface grinding, 1-mm cracks by compression with a Vickers bit, and 4-mm cracks by 3-point bending. Only the 3-point bend cracks produced thermal images. Several parts shattered during testing, perhaps by being forced at resonance by the 20-kHz acoustic probe. Tests on damaged carbon composite coupons produced thermal images that were in excellent agreement with ultrasonic inspection. The composite results also showed some dependence on contact location of the acoustic probe, and on the method of support. Tests on glass with surface damage produced weak images at the pits. Tests on metal ballistic targets produced thermal images at the impact sites. Modal analyses suggest that the input frequency should be matched to the desired response, and also that forced resonance damaged some parts.