This paper summarizes the results of a survey of over three hundred maintenance personnel who use imaging equipment within their company or organization. All had previously participated in one or more of our training programs. The companies took in a broad range of industry, including, among other, power generation, pulp and paper, metals, mining, petrochemical, automotive and general manufacturing. The organizations were mainly quite large, either commercial or public, and included governmental agencies, military, colleges and universities, municipalities, and utilities. Although we had a very tight time line for the survey, we were pleased to have a 15% response rate. The results show that some of the causes of success and failure in infrared programs are not unlike those associated with any type of program in an organizational structure, i.e. the need for accurate and timely communications; justification requirements; etc. Another set of problems was shared more closely with other startup maintenance technologies (for example, vibration monitoring), such as the need for trending data; providing appropriate technical training; achieving reproducible results; etc. Finally, some of the driving mechanisms are more specific to this technology, such as re-designing equipment so that it can be thermally inspected; establishing effective documentation strategies; etc.

An infrared imager measures the radiant energy of an object and converts the data from the infrared region of the electromagnetic spectrum to the visible region of the electromagnetic spectrum. The result is a thermographic image of the object, from which temperature information can be gathered. Only the surface of an object can be imaged, and therefore only the surface temperature can be measured by the radiometer. This characteristic of infrared imaging can pose a problem when the temperature beneath a surface is pursued. Even in cases where a subsurface heat source makes a distinct thermal pattern on the surface that is imaged, the measured surface temperature is not necessarily the same as the actual source temperature. The surface temperature combined with thermodynamic principles and related material properties provides enough information to calculate the subsurface temperature, and so a thermographer has the ability to image a surface to determine the temperature beneath it. A practical application in this area is imaging the ground to locate and calculate the temperature of buried steam lines used in large heating distribution systems found in cities and college campuses. Presented here are formulas for calculating the heat loss and temperature of a buried steam line.

Computerized Infrared Thermographic pipeline inspection is now a refined and accurate process having been thoroughly proven to be an accurate, cost effective, and efficient technology during a 10 year development and testing process. The process has been used to test pipelines in chemical plants, water supply systems, steam lines, natural gas pipelines and sewer systems. Its non-contact, nondestructive ability to inspect large areas from above ground with 100% coverage and to locate subsurface leaks as well as the additional capability to locate voids and erosion surrounding pipelines make its testing capabilities unique. This paper will detail the development of computerized infrared thermographic pipeline testing along with case histories illustrating its implementation problems and successes and innovations anticipated for the future.

The use of the infrared technology at Davis-Besse for predictive maintenance applications has proven itself. Since late 1987, the infrared work has been conducted in-house to support other techniques or as a sole predictive maintenance technique. The topic of this paper will be to review some of the applications and the results achieved. The areas which will be reviewed are in the Electrical Distribution System, the Control Rod Drive System and steam applications.

Following a series of failures of the lubricated couplings of the Reactor Feedpumps at the Peach Bottom Units 2 and 3, thermographic monitoring of these couplings was initiated. Baseline data was collected for all six feedpumps and a monitoring frequency was established. Data was collected over a three month period, and a trend-to-failure was developed both qualitatively and quantitatively. The motion of the coupling was effectively strobed by the infrared camera to allow the interpretation of heat patterns on the coupling surface. By keeping stored infrared images and comparing them to the as-found condition during coupling inspections, it became possible to identify heat patterns that were characteristic of lubricant degradation of coupling tooth breakage situations. In addition, data was compared to certain operating parameters to help determine root cause for the failures. To accomplish this, real time temperature data was obtained for selected points on the coupling profile during certain transients which presented a comparison to changing parameters. In this way, certain design criteria were more thoroughly analyzed for their applicability to the currently experienced loading of the couplings.

After years of providIng Infrared Thermographic (IR) studies at the same locations year after year on corporate based programs, do the clients still consider that "the service is worth it?" The answer depends on how the results are analyzed and communicated to management. The statistics show that the dollar savings continue and are significant year after year. In summary, identifying and reporting one major problem "before failure" could cost justify an entire corporate based program for all facilities! American Risk Management Corp. (ARM) has performed thousands of IR tours at all types of industrial accounts since the mid 1980's. The tours are typically for electrical loss prevention and always study high voltage systems and as much of the low voltage systems as the client authorized. Full documentation of areas studied is provided as a list of objects scanned. The anomalies found that are suspected problems are fully documented and reported. These findings are prioritized as critical, severe, intermediate and minor based on the generally accepted temperature over ambient criteria.

The title of this paper may seem surprising and, to some, clearly a case of heresy. However, a look at the statistical representation of the classic 'bathtub reliability' curve, suggests that, at some point, the numbers of 'findings' from an Infrared Thermographic (IR) program could diminish to zero for a period of time. Therefore, a facility may be left with an expensive piece of equipment, an extensive inspection program, trained thermographers, and few reportable results. This paper deals with some suggestions for preparing for this inevitable situation.

The use of infrared thermography equipment at Palisades is developing into a useful tool for our Predictive Maintenance Program. We have selected thermography as the most desirable method to accomplish our goal of predicting equipment condition and reliability. The testing of components without system disruption is one of its largest assets. Presently, we are starting a new program to reduce our Preventive Maintenance (PM) man-hour work load in the Electrical Maintenance area; from an average of approximately 76% to a goal of 50%.

Thermographic predictive maintenance is well established in industrial practice. However, thermographer qualifications vary in the extreme, causing severe problems for practitioners and users alike. The need for standardized experience and training criteria has been acutely felt in this application and in the aerospace industry application of materials non-destructive testing. A Personnel Qualification committee was formed by the American Society for Non-destructive Testing (ASNT) at the Fall 1989 conference in Valley Forge. A number of us from the thermographic community are directly involved. The committee's immediate purpose was to develop standards and test questions for inclusion in ASNT Standard Practice STC-TC-1A. The overall purpose is to arrive at a recognized thermographer certification program. George Baird was appointed chairman and Russ Mack of Dow Chemical was appointed vice chairman. They have since swapped jobs. An informal set of standards was generated shortly thereafter and circulated to the committee. Quite a bit of intensive discussion followed at committee meetings at the ASNT San Antonio conference and at Thermosense in Orlando, as well as by telephone. The main issues that developed were: 1. Experience requirements. 2. Training subjects and time. 3. Permitted activities for each leveL 4. Adherence to ASNT standard practice. A formal ballot on a standard went out to the committee in August 1990 and was approved. These draft requirements are now working their way through the various ASNT committee approvals. Examination questions are being solicited for approvaL We hope to have an approved set of training and qualification guidelines ready for use by this time next year.

With the adoption of American Concrete Institute's Design Standard 530 (ACI 530-88/ASCE 5-88) and Specifications (ACI 530.1-88/ASCE 6-88) by more governing bodies throughout the United States, the level and method of inspecting masonry structures is rapidly changing. These new standards set forth inspection criteria such that the Professional of Record (i.e., Architect), can determine the level of inspection based on the type and complexity of the structure being built. For example, a hospital would require considerably more inspection than a Seven-Eleven mini-market. However, the standards require that all new masonry buildings must be inspected. Infrared thermography has proven to be an effective tool to assist in the required inspections. These inspections focus on evaluating masonry for compliance with the design specifications with regard to material, structural strength and thermal performance, the use of video infrared thermography provides a thorough systematic method for inspection of structural solids and thermal integrity of masonry structures. In conducting masonry inspections, the creation of a permanent, well-documented record is valuable in avoiding potential controversy over the inspection findings. Therefore, the inspection method, verification of findings, and presentation of the inspection data are key to the successful use of infrared thermography as an inspection tool. This paper will focus on the method of inspection which TSI employs in conducting new masonry inspections. Additionally, an important component of any work is the presentation of the data. We will look at the information which is generated during this type of inspection and how that data can be converted into a usable report for the various parties involved in construction of a new masonry building.

This paper presents a technique to detect the moisture conditions of walls supporting frescoes in order to detach its in case and to understand causes of the surface wetting. An important feature of the testing procedure is to be nondestructive and appropriate to analyze large surfaces as it is based on thermographic image processing. The goal is to classify the wall surface on the basis of its moisture condition. We choose the thermal inertia as the most suitable parameter for this purpose, because the heat capacity of a porous body increases to a great extent by varying its water content. The test works modifying the wall inner thermal conditions and detecting temperature variations of the fresco, in time and space domain. For this purpose a convective thermal flux is uniformly applied to the surface while an infrared camera views it. In such a way temperature gradients appear, whose maximum directional variation curves are used to segment the surface and the mean temperature time difference is used to label each area. The key point of the proposed procedure is the freedom from the knowledge of the wall composition and its thermal and hydrologic dynamic status, depending on weather history. Other topics as the environmental radiometric reflection and emission, the 'Narcissus effect' in thermograms mosaic composition and the perspective distortions are considered. Experimental results on a XVI century church at Padua (Italy) are presented.

One of the issues facing the Thermographic industry is providing the assurance to customers that surveys are performed properly and that the reporting provides sufficient information to give the desired answers. Reputable thermographers are continually fed with competitors who provide services which are either imKcurate, improperly carried out or interpreted, or which do not satisfy the client. This less than satisfactory service continues to threaten the acceptance of all thermographic applications. The American Society for Testing and Materials (ASTM), has been in the business ofproviding uniform, generally accepted standards for testing for over 90 years. The standards published by ASTM go through an extensive review phase which assures that the fmal standard reflects industry standards. Additionally, standards are periodically reviewed for changes which assures that they contain the latest technology. ASTM Cl 153-90 is the recently approved ASTM Standard Practice for the Location of Wet Insulation in Roofing Systems Using Infrared Imaging. The scope of the standard is limited to those techniques which employ the use of JR imaging systems at night to locate and delineate areas of wet roof insulation located above the deck and below the waterproofing system of a roofing system. The practice outlines the minimum criteria for the infrared imaging systems, the effect of meteorological conditions, roof construction, and verification criteria. The standard also states the minimum necessary operating procedures for a successful survey. It is not the intention of this standard to present all of the principles which apply to the application of infrared technology to roof moisture surveys but rather to outline the minimum criteria for an acceptable infrared roof moisture survey. ASTM standards are divided into sections which correspond to the various functions of the standard. In addition to a statement of the scope of the standard, all standard practices must include a section on Significance and Use2. Other sections which are included in this standard practice are: Terminology Infrared Survey Techniques Instrument Requirements Level of Knowledge (of the operator) Limitations (Applicability of Constructions) Significant Environmental Parameters Required Conditions Inspection Procedures Data Interpretation Verification Report Precision and Bias This paper will discuss the key elements of each of these sections and in particular those elements which were developed specifically for the roof examination standard practic

Infrared thermography has been used in building research at the Technical Research Centre of Finland (VTT) since 1975. Traditionally this technique has been used to localize defects in thermal insulation and air tightness in the external envelope of buildings. During the past few years it has also been applied successfully to assessing the condition of facades and detecting moisture in structures. This paper briefly describes our experiences with thermography in building research. Multispectral technique has been applied to concrete facades. The principle of this method is also presented in this paper.

Installing insulation in the core of masonry construction has become acceptable in the construction industry. A method of inspecting the walls is needed that can be performed before the building is completed. This paper is an infrared study of masonry construction relying on thermal changes created by environmental temperature patterns and sun loading on the structure. A temperature verses time study is conducted to determine the most advantageous time frame in which the study should be conducted.

Thermographic methods have a good accuracy in indicating damages and energy related conditions of building envelopes. Radiative temperature patterns indicate the extension and character of building anomalies, while radiative temperature differences indicate the severity of the anomaly. However, the usefulness of applying thermography increases substantially if combined with complementary methods. Photographic inspection, using fiber optics, of the interior of the building envelope confirms the indicated occurrence of air leak paths. The influence of air leaks may be quantified by measuring the air change rate using tracer gas techniques. The energy losses for various building components can be calculated using as input building design data and thermographic data. To retrofit or implement energy conservation measures of buildings, the most cost-effective measures must be identified. This requires the collection of relevant technical and economic data. Thermography and complementary methods provides data for making a priority between different possible measures. In this paper, we present the results from a detailed study of one building that was to be retrofitted. Before the retrofit, we analyzed the probable reduction in energy consumption for different measures proposed. Also, the highest investment cost compatible with the investment pay-ff criteria required by the building manager was calculated for each measure. This information was presented in the form of a priority list to the building manager and the contractor. Some measures were selected for implementation. After the retrofit, we have carried out an evaluation of the cost-benefit of the

The use of sensors in arc welding processes is typically complicated by the intense light and electrical noise emanating from the arc. In consumable electrode processes, data acquisition is further complicated by the generation of metal spatter. The objective of the current work was to develop noncontacting diagnostic techniques for monitoring temperatures during arc welding. The purpose of the diagnostics was to provide experimental data for both weld model input and computer model verification for gas metal arc (GMA) welding. These techniques have also been applied to gas tungsten arc (GTA) welding.

The cost of printed circuit boards with multi-layered voltage planes has created the need for an easy to use tool that can detect, locate, verify and analyze hidden defects causing shorts. The use of a Thermal Image Analyzer (TIA) in conjunction with a hipot test and high voltage stress give manufacturing such a tool. This tool, controlled by a personal computer, directs the operator in the correct analysis procedures needed to safely detect, with thermal image analysis, the defective area of the product. The tool is capable of applying a high-voltage test and low- current stress to leakage defects. The tester can then apply constant power to the defect using low voltage (less than 24 VDC), enabling detection with the TIA. The entire operation is transparent to the manufacturing operator who when trained in the use of the TIA, can detect, isolate, categorize and repair internal and/or surface defects related to multi-layered printed circuit boards. This paper deals with the infrared detection and repair of defects in printed circuit boards as a manufacturing process.

The concept of using IR imaging technology in locating failures in populated and unpopulated printed circuit boards (PCB) has been around since the mid 70's. However, the use of IR imaging technology in predicting component failure has been almost nonexistent. An IR workstation was developed to identify components that had become degraded as a result of aging, stress, or 'wear and tear'. Unlike previous work in IR diagnostic which uses a 'gold' image for comparison, the image history is developed on an individual board basis. The boards were subjected to both thermal and voltage stress to induce component degradation and failure. Preliminary results indicate that some components show a consisted thermal profile that may be used in predicating the lifetime of some components; other components exhibit no consisted thermal pattern change. Due to the varying statistical nature of stress to PCB modules during use in the field and the complexity of designing thermal simulations for each type of PCB module, designing a low cost IR workstation to predict component lifetime is not practical. However, a related application of the effort offers the means to significantly enhance the reliability of PCB modules which have large populations.

The production of peat supplies approximately 4 % of the total energy consumption on Finland. Peat is produced in bogs, where the produced fuel is stored in stockpiles. Because of self-heating caused by microbe activities and chemical reactions there is an annual loss of about 5% of the energy content of stored peat. The supervision based on visual control combined with manual temperature measurements carried out on the peat bog is expensive, and furthermore a very unreliable method. Because the warm patterns in the peat stockpiles are not necessarily found. The damages can partly be avoided when self-heating is observed in time and the necessary actions are carried out. The Research Institute of Northern Finland, University of Oulu, started an experimentation of airborne thermal scanning supervision of peat stockpiles on initiative of A. Jalander Oy, a subsidiary of Kemira Oy, in 1987. The field studies have been made as a co-operate project of the Research Institute of Northern Finland and Building Laboratory, Technical Research Center of Finland (Oulu, Finland). During the experiment 2800 thermograms were taken of peat stockpiles, the inner temperature of 200 of the stockpiles being controlled on the bogs. On the basis of the studies it has been possible to define the criteria for thermal scanning of peat stockpiles. Depending on the weather conditions, even a difference of 2 degrees in the surface temperature of the stockpile can indicate a warmed pattern. In autumn 1990 a regular airborne supervision based on thermal scanning was started on the peat bogs of two producers, the peat bogs containing altogether approximately 1 million m3 of peat, the area supervised being about 3500 hectares. The flights were made three times an autumn with intervals of 4 weeks. The flights have been made on a four-seated airplane, the frame of which was equipped with a hole for the infrared scanner. The results were documented on videotape, and video printer shots of the suspected warmed stockpiles were sent to the producers. The supervision has proved to be quite reliable. The self-heating of the stockpiles has been observed at an early stage long before the ignition. The costs of airborne supervision have been covered with the amounts of the saved energy.

Work within the process industry is often carried out on machines with high surface temperatures (above 50 degree(s)C). This often gives rise to poor indoor climate with an unsatisfactory thermal climate for staff. These problems can be solved or reduced by radiation screening. In practice, light foil materials (films) will often prove a good and inexpensive solution for screening. However, these types of materials have varying radiation properties. A method has been evolved to evaluate quantitatively the various materials' capacity for heat radiation screening. The method is based on use of a thermographic camera. The results are compared with an indoor climate analyzer for asymmetric radiation measurements, and show good agreement. Furthermore, on the background of laboratory measurements, thermography has also been employed to ascertain heat loss from process machines. This has been used to calculate convection flows for use in designing exhaust hoods. Laboratory measurements prove that for surfaces of a simple geometry and with surface temperatures over 50 degree(s)C the heat loss can be ascertained with an accuracy of approx. 10%. These experiments were carried out at Lindab Riscancos laboratory in Farum and DTI's laboratory for testing radiators during spring 1990, as a link in a larger project concerning improvement of thermal working conditions in industrial dye works. The project is financed by the Danish Ministry of Energy.

Over the last years thermographic methods have gained considerable ground for temperature measurement on electronic components like PCB:s, hybrids and microchips and quite a large number of articles and lectures have been published. Very little consideration has, however, been devoted to the fact, that the very uneven distribution of the emissivity over the PCB, hybrid or microchip to be measured implies that true temperature measurement cannot take place without special efforts in the form of hardware as well as software tools. The paper describes a method for true temperature measurement on PCB:s and microchips, with consideration to the varying emissivity over the field of view. It also describes a method for true temperature measurement on PCB:s in a rack or a box, where they are hidden for direct thermographic inspection. True temperature measurement on microscopic objects like transistors form another type of object, which demands special measurement hardware and extensive image processing to get the correct temperatures.

The temperature rise distribution in a snow ski track yields information on the performance of the ski. High temperature rise indicated high pressure such as an edged ski while low temperature rise indicated less pressure such as a gliding ski. Preliminary research is performed on snow ski tracks using infrared thermography. Several thermograms are presented showing the temperature rise in ski tracks on a motorized ski deck and on a ski slope. Temperature rise (about 7C) was easily acquired on the motorized ski deck because of the high coefficient of friction between the ski and the ski deck nylon carpeting. Temperature rise on the ski slope was much lower (about .3C) and much more random because of snow surface variations. Preliminary results indicate that infrared thermography can be developed into a useful tool by the snow ski designer.

Temporal aliasing is a problem common all video imaging systems. IR video systems are particularly susceptible because of the relatively low (30 Hz) RS-170 frame rate. We have developed a system which compensates for the effects of aliasing, and allows images of repetitive thermal phenomena at frequencies up to 4 kHz to be acquired. The system utilizes an unmodified commercial imager (Inframetrics IR 600) and a microcomputer. Data is acquired selectively using a 'line-by-line' scheme which compares the motion of the camera's horizontal scanning mirror to a reference signal correlated to the event of interest. Only those horizontal lines that have a user-specified phase relationship to the reference signal are acquired. The resulting images have an effective integration time of 125 microseconds. This ability to acquire 'time-resolved' IR images allows investigation of phenomena not possible with a conventional RS-170 IR imaging system. For example, a conventional thermal image of an integrated circuit operating at several kilohertz yields no temporal information whatsoever. By comparison, we have acquired time-resolved images which show the AC heating and cooling of the circuit, so that we may identify AC hot spots. The system has also been applied to a running internal combustion engine. The imager views the piston head through an IR transparent (ZnS) window. Acquired images clearly show the motion of the flame front through the combustion chamber, and the subsequent heating and cooling of the piston head.

IR thermography constitutes an especially useful tool for the extraction of 3D information, since it can in a single test setup both identify the overall relief of an object and quantify potential subsurface defects. Heat transfer modeling can take advantage of this 3D calibration of the thermal stimulation apparatus; the associated temperature rise becomes a known measurement for all surface mesh nodes and time-intervals. This path would greatly enhance the validity of heat transfer modeling.

Exploitation reliability of porous thermal insulation depends strongly on its moisture because the excess water leads to its destruction under extreme conditions. Active and passive thermographic methods are described to estimate the distribution and quantity of water inside the insulation by using the Soviet thermoviser TV - O3 and IR pyrometer.

In the present study we discuss two thermal methods, namely vibrothermography and thermoelastic emission (SPATE), for NDE of composite materials. Both methods take advantage of 'local resonance', i.e., independent flaw dynamics, to detect and evaluate damage. Complementary information about the flaw position, size and depth can also be obtained. These methods are fast, practical, and can be performed 'in situ'. The SPATE system can also reveal delaminations in relatively thick structural components.

Illustrative examples are presented of the quantitative results obtainable from pulse-video thermography (PVT) for a variety of fields, emphasizing the character of the pictorial representations which is anticipated to be most useful for quality-assurance management. The ability to obtain sequential frame-grabbed thermal images has greatly improved PVT data, opening the way for digital processing of thermal-transient images, as well as the determination of thermal diffusivity and effusivity over large areas.

Photoacoustic microscopy by photodeformation can be used to generate imagery on a micrometric scale. It may be used for nondestructive testing, especially in the microelectronics industry. A quantitative application of this method is presented here, for making relative measurements of thermal diffusivity of samples of a few tens of cubic micrometers in volume. The measurement is relative because it requires a reference sample of known diffusivity. Possible applications are thin films, very small homogeneous samples exhibiting high gradients of thermal properties, thin coatings, etc. Some results are presented for bulk materials and diamond-like carbon thin coatings.

The fact that organic binders, as used in paints, are transparent in the IR range 3.5-5.5 microns is utilized to detect and measure defects under the paint film of sheet metals. However, the method demands an elevated sample temperature to suppress reflections from the surrounding and is till now resorted to laboratory investigations. The IR system used is an AGEMA Thermovision 880 SWB. The maximum thickness of the paint film allowing evaluation is mainly governed by the absorption and the refraction caused by the paint pigments, depending upon pigment size and pigment material. To be detectable the defects have to be characterized by IR emissivities considerably different from the emissivity of the bare sheet metal as is found for metallic corrosion products. A quantitative determination of a corrosion attack is obtained by evaluating the IR image at a PC based image analyzer. As a standard today, such evaluations are performed by inspecting and comparing painted sheet metals with reference photographs. This method suffers both from the subjectiveness of the observer and the opaqueness of the paint film in the visible range.

Pitch-based graphite fibers, when used as a reinforcement in either polymeric or metal matrix composites, can significantly increase the in- plane thermal conductivity. An opportunity is thus presented by these composite materials to passively manage waste heat in electronics applications. Rule-of-mixtures calculations have predicted the thermal management performance of these composite materials when the fibrous reinforcements are in the form of either woven fabric or tape layups and the reinforcement orientation is either unidirectional or cross-plied. Many factors, however, complicate the prediction, including: fiber-to- matrix interfacial thermal resistance, the interply thermal resistance, and the highly anisotropic fiber thermal conductivity. Verification of the predictions was sought by the use of IR thermography. Heat was applied by a point source to the surface of the composite while the resulting thermal pattern was monitored and recorded thermographically.

The thermal inspection technique of time-resolved infrared radiometry (TRIR) has been developed as a nondestructive characterization method for examination of multilayer materials systems. Applications of the technique include detecting defects such as disbonds in protective coatings which could lead to coating failure. This technique is an extension of earlier thermal wave imaging techniques developed for examination of material microstructure and defects. The TRIR technique is totally noncontacting and allows quantitative measurements to be made of both the coating thickness and the integrity of the bond between the coating and the substrate within the same measurements. In the present work we review the basics to the TRIR technique and examine the use of the TRIR technique for inspection of organic coatings.

We present applications of our infrared thermal wave imaging system which was described in detail at Thermosense XII. In brief, the system consists of an infrared video camera and a real time image processor under the control of a computer workstation, together with various time- dependent heat sources. The heat sources are used to launch pulsed or periodic thermal waves into the target, and the camera is used to record the thermal waves scattered back to the surface by sub-surface thermal features (cracks, coating substrate boundaries, inter-ply delaminations, etc.). Recently we have succeeded in developing an additional capability for this instrumentation, namely the ability to make quantitative depth and thickness measurements. Furthermore, some of the authors, together with V. Vavilov of Tomsk Polytechnic, have demonstrated a capability of carrying out thermal wave tomography. We have recently extended this technique to real time with our system. We describe these recent developments and present several applications to the study of thickness variations and adhesion defects in coatings and composites.

The simulation of images generated by thermally-radiating, optically- thick turbulent media are discussed and the time-dependent evolution of these images is modeled. This characteristics of these images are particularly applicable to the atmosphere in the 13-15 mm band and their behavior may have application in detecting aviation hazards. The image is generated by volumetric thermal emission by atmospheric constituents within the field-of-view of the detector. The structure of the turbulent temperature field and the attenuating properties of the atmosphere interact with the field-of-view's geometry to produce a localized region which dominates the optical flow of the image. The simulations discussed in this paper model the time-dependent behavior of images generated by atmospheric flows viewed from an airborne platform. The images ar modelled by (1) generating a random field of temperature fluctuations have the proper spatial structure, (2) adding these fluctuation to the baseline temperature field of the atmospheric event, (3) accumulating the image on the detector from radiation emitted in the imaging volume, (4) allowing the individual radiating points within the imaging volume to move with the local velocity, (5) recalculating the thermal field and generating a new image. This approach was used to simulate the images generated by the temperature and velocity fields of a windshear. The simulation generated pais of images separated by a small time interval. These image paris were analyzed by image cross-correlation. The displacement of the cross-correlation peak was used to infer the velocity at the localized region. The localized region was found to depend weakly on the shape of the velocity profile. Prediction of the localized region, the effects of imaging from a moving platform, alternative image analysis schemes, and possible application to aviation hazards are discussed.

Bats are often difficult to observe in their natural habitat. Because of their nocturnal, acoustically oriented behavior and their tendency to group together in inaccessible crevices, researchers have been limited in their ability to obtain even the most basic data on their ecology and behavior. A number of strategies have been used to quantify the behavior of bats in their natural environment. Since 1978, when Slusher first introduced military night vision applications at the Entomological Society of America symposium, there have been few applications of similar techniques in the study of bats. In the study of bats, infrared imaging provides these advantages: it is portable; self-contained; non- invasive; and can provide a permanent recording of bat location and behavior which may be used for subsequent laboratory analysis and comparison, and is especially effective where stop and slow motion video permits observation of transient occurrences and allows for sampling techniques. In the current study, big brown bats, Eptesicus fuscus, were first observed in a laboratory setting to determine their responses to the presence of the IR imager. Following the determination of its non- invasive nature, big brown bats were located and observed in natural surroundings. The data obtained showed that infrared imaging has potential application in counting emerging bats; counting or estimating size of nesting colonies or area occupied in situ; location of bats roosting in inaccessible sites; non-invasive behavior investigation such as following movement of individuals in the roost; diagnosing infection sites in injured bats; image processing for both graphic presentation and analysis of data.

Heat production in biological systems is an obligate consequence of the chemical thermodynamics of the living state. Various cellular and systemic mechanisms exist of the dissipation (or conservation) of this net heat production in a basically aqueous environment to various exchange surfaces. Besides fundamental conduction, and radiation, convective modes of heat transfer are particularly significant, the latter often establishing steady-state thermal gradients particularly at normal or experimental exchange surfaces. Considering the relatively high specific heat of water and the low level of heat generation, the magnitude of such gradients are small and this require methods with sensitivity < 0.1 degree(s)C, with reasonable time response, and ones adaptable to quantitative spatial mapping. To that end, we have developed a calibration procedure and protocols employing a variety of thermotropic liquid crystal (TLC) formats which can quantitatively map both cellular and tissue surface gradients in a reproducible manner. TLC's used in a quantitative mode have the extreme temperature resolution required for basic biological studies, as well as application where altered cellular metabolism and/or vascular flow patterns are manifested as thermal changes in the spatial thermogram. This paper provides preliminary data on the application of the above protocols for the assessment of the dynamic changes in the thermal gradient pattern on the left-ventricular surface of supported, experimental heart preparations. Accordingly, after initial capture of the calibrated TLC images onto videotape using a multichannel plate intensifier (together with A/D conversion of physiological signals), single frame digitization allows for exact quantitative correlations of changes in the thermogram with hemodynamic parameters throughout the cardiac cycles with a time resolution of approximately equals 33 msec. The type of information obtained has potential value in clinical cardiac diagnosis (ie. coronary artery disease, by-pass assessment, etc.) and other biological applications where altered flow and/or heat production leads to changing surface gradients (ie thrombosis, embolism, tumor cell heat production, etc.) which can now be accurately and quantitatively mapped by the use of TLC's.

An algorithm has been developed to reconstruct the internal temperature distribution within a rising buoyant thermal from measurements of the radiances by an infrared imaging camera. The technique is applied to detonation of a stoichiometric mixture of methane and oxygen contained in a three-meter diameter mylar balloon. The temperature-time histories of the evolving fireball showed torus formation, followed by rapid cooling from entrained ambient air. Comparison of the temperature distribution with results of an Eulerian hydrodynamic computer code shows good agreement except at the center of the fireball. A possible explanation might be the lack of an entrainment mechanism in the hydrocode.

Natural color (NC) and color infrared (CIR) video systems were used to acquire oblique and near-nadir imagery of citrus grove areas that were damaged by cold temperatures during the nights of February 25 and 26, 1989. Two flights were made 10 days apart from 9:30 am to 12:00 noon each day at 100 m and 300 m altitudes. The video cameras adjusted to the changing light intensity caused by cloud interference and turbulent weather and produced acceptable images for the detection of freeze damage and delineation of damaged areas. The contrast between green and brown video images was less distinctive than the contrast between cyan and magenta of the CIR video. Both NC and CIR video cameras captured images of damaged citrus trees, but it was not possible to measure the areas with an image analysis system because images were oblique and were acquired in different overflights of the damaged areas. The major benefits derived from videography were instant acquisition and viewing of images, rapidly locating damaged areas, and determining that all sites were imaged.

The present ad hoc method for determining the physical properties of particulate exhaust plumes inverts multiband irradiance data collected over fields-of-view that are highly oblique to the plume axis; it is therefore applicable to the onboard measurement of in-flight aerodynamic effects on plume properties. A simple analytical model that predicts irradiance under these assumptions is presented, together with measurements of Mg/PTFE plumes in vacuum. The first step of the inversion process generates the locus of possible temperatures and velocities consistent with a given irradiance measurement; the second step uses two independent irradiance measurements to ascertain a unique temperature and velocity solution.

The quality of electronic products is directly dependent upon that of solder joints on printed circuit boards (PCB's). The inspection of solder joints quality by use of both Laser and Infrared technology is an advanced technique. However, small signal and low signal-to-noise ratio (S/N) require the system to have a high sensitivity to temperature changes. In order to overcome them, in this paper, two methods to enhance signal and S/N in certain laser beam power and warming time are proposed and experimented. The theoretical analysis and experiment results show that: (1) When laser beam is injected into the solder joints at a certain angle with the normal of their surface, the signal and S/N increase, in general, the increment is 2-3 times. (2) When the solder joints is located at a position with a distance from the focus of thr optics, where the solder joints are just full of the field of view of the optical system, the S/N can be improved. In this case, the requirement on the stability of working is largely loosened.

The video recording of dynamic experiments using infrared thermography can produce large numbers of images. Ten seconds of video includes 300 frames, each of may contain useful information. Automation is necessary to reduce the analysis time to an acceptable level. Since each experiment will have its own unique characteristics, the development of custom software for each analysis by a professional programmer is unreasonably expensive. A better approach is to implement a programmable interface to a general-purpose analysis program which the experimenter can program for a specific analyses needed. Version 3 of the Video Data Analysis System (VDAS) incorporates such an interface. In addition to standard programming language commands for arithmetic, input/output and flow to control, VDAS includes facilities for image processing, quantitative temperature and emissivity measurement, scanner calibration, noise and artifact reduction, and temperature contouring. An on-line help system describes the available commands or helps the user find the right command for a particular purpose. Additional commands allow the user to control a video disk player and recording for automatic processing of complete video sequences.

A diagnostic system has been developed to measure the temperature of a pulsed thermionic cathode. The thermionic cathode consists of more than 150 tungsten filaments each brought to over 2500 Kelvin in less than 10 msecs. Four optical fibers can view the cathode array and feed their light through a spectrograph (150 g/mm) into a silicon vidicon detector. An optical multi-channel analyzer (OMA) controls a pulse generator which can gate the vidicon from 70 nanoseconds to 1 millisecond. The spectrum of the tungsten source is recorded from 450 to 750 nm (across 512 channels) on four separate tracks (corresponding to each fiber). The OMA converts the count verses wavelength data to an ASCII file. A computer program has been developed which applies appropriate calibration factors to the raw data, fold in emissivity values as functions of wavelength and temperature, and provides two-color temperature measurements across the 512 channels. A simple statistical routine then determines mean and standard deviation of the temperature measurements. The system can be applied to the remote sensing of CW or pulsed thermal sources. Background measurements can be taken prior to data collection and then subtracted from raw data. Temperature values for a single pulsed tungsten filament are compared with integration of pulsed power heating.

The Class II Thermal Imaging Common Modules were originally developed for the U.K. Ministry of Defence as the basis of a number of high performance thermal imaging systems for use by the British Armed Forces. These systems are characterized by high spatial resolution, high thermal resolution and real time thermal image update rate. A TICM II thermal imaging system uses a cryogenically cooled eight element Cadmium- Mercury-Telluride (CMT) SPRITE (Signal PRocessing In The Element) detector which is mechanically scanned over the thermal scene to be viewed. The TALYTHERM system is based on a modified TICM II thermal image connected to an IBM PC-AT compatible computer having image processing hardware installed and running the T.E.M.P.S. (Thermal Emission Measurement and Processing System) software package for image processing and data analysis. The operation of a TICM II thermal imager is briefly described highlighting the use of the SPRITE detector which coupled with a serial/parallel scanning technique yields high temporal, spatial and thermal resolutions. The conversion of this military thermal image into thermography system is described, including a discussion of the modifications required to a standard imager. The technique for extracting temperature information from a real time thermal image and how this is implemented in a TALYTHERM system is described. The D.A.R.T. (Discrete Attenuation of Radiance Thermography) system which is based on an extensively modified TICM II thermal imager is also described. This system is capable of measuring temperatures up to 1000 degrees C whilst maintaining the temporal and spatial resolutions inherent in a TICM II imager. Finally applications of the TALYTHERM in areas such as NDT (Non Destructive Testing), medical research and military research are briefly described.

This paper presents an overview of what features a state-of-the-art thermal imaging system needs to posses to be an accurate temperature measurement system. In thermography one of the major problems is a consequence of the fact that the surface temperature is not measured directly but is computed from the radiation received by the detector. This radiation consists not only of radiation emitted from the object but also from the surroundings, the atmosphere and the thermal imager itself. A thermal imaging system which compensates for this unwanted radiation is described. The influences from the surroundings, the atmosphere and the thermal imager is treated. The use of temperature references in the optical path, temperature sensors for measuring the imager temperature for compensation of its own radiation is described. Spatial resolution, calibration and accuracy of the imager are also discussed.

The reliability of some algorithms commonly used in inferring surface temperature from infrared radiation has been investigated. Single-band, two-color and multiwavelength pyrometry methods have been considered. The signal received by the pyrometer was computer simulated by taking into account the spectral emissivity of the target, the effects of atmospheric absorption and self-emission, the selective transmittance of the optics, the contributions due to surrounding bodies and the spectral response of detector. The reliability of the algorithms was obtained by computing the difference between the true target temperature and the calculated one. Results indicate that a good knowledge of target emissivity and atmospheric transmittance is required to achieve a reasonable accuracy. The simulation allows also to predict the increase of temperature error when the atmospheric radiance is not negligible or when a low-emissivity target reflects the radiation from surrounding bodies into the field of view.

This paper describes a method which can be used to measure the point spread function of thermal imager. The images of a sharp thermal edge at 36 different orientations are digitally processed to produce line spread functions which are projections of the point spread function. For the reconstruction of the point spread function, the filtered-backprojection algorithm is applied. The experi mental result has been presented with the discussion.

Analyses are conducted in order to develop a method for quantitative determination of internal cavities and foreign inclusions in solids on the basis of IR thermography. The results thus obtainable as especially applicable to cases suitable for modeling in 1D heat-transfer mode within a straight slab of constant or variable thickness, under quasi-static thermal conditions and in the absence of internal heat sources. A local dimensionless thermal parameter is defined for detection and interpretation of detected cavities and inclusions; the explicit prediction of their minimum detectable volumetric fraction depends on thermal imager resolution, slab thickness, and thermal conductivities.

Infrared imaging used in aerodynamic research evolved during the last 25 years into a rewarding experimental technique for investigations of body-flow field viscous interactions, such as heat-flux determination and boundary layer transition. The technique of infrared imaging matched well its capability to produce useful results, with the expansion of testing conditions in the entire spectrum of wind tunnels, from hypersonic high-enthalpy facilities to cryogenic transonic wind tunnels. With unique achievements credited to its past, the current trend suggests a change in attitude towards this technique: from the perception as an exotic, project-oriented tool, to the status of a routine experimental procedure.

This paper describes the results of a five-year study carried out in 38 power substations (230, 115, 34.5 and 13.8 Kv), located in the Western power electric system of CADAFE (Venezuela's national Electric Utility). A total of 154 hot spots were found between 1980 and 1982, a time span considered a reliable source of information in connection with methodology, term and results. The distribution of hot spots found during those years was 77, 33 and 44. The reduction of the spot/substation parameter was found to be 4.1, 3.3 and 3.1, respectively. Every item detected could have been the cause of major interruptions, locally and regionally, or even the system's blackout. The methodology used to determine the major concentration of findings and their location on the equipment, followed the sequence of Pareto's Diagram and Ishikawa's Graphic. Based on the results of the study whose results are presented here, a lubricant and compound-aid connector for Al-Al and bimetallic electric connections was formulated, developed, manufactured, tested (at IREQ laboratories) and traded (CONECTECH CAC- 01). To date, the whole process represents 12 years of work. The connector's behavior and reliability are being tested throughout Venezuela's national electric system (responsible for the supply of around 50,000 Gwh/year) with the use of 12 Tons of CONECTECH CAC-01.

This paper describes the application of thermal imaging to the bottle forming process. Much is unknown about the variables involved in producing a bottle. This lack of familiarity leaves room for defects which results in a loss of money and production. There are different types of cooling techniques used in forming bottles. The Coors Glass Manufacturing plant currently utilizes two distinct cooling methods, Stack Wind and Vertiflow. The focus of this study is on the efficiency of the Vertiflow cooling system. Thermal imaging is used to analyze the cooling effect due to different variable changes. The goal is to achieve uniformity in the iron temperature and glass flow which improves the quality of the bottle and also allows for a reduction in the total amount of glass necessary to form a bottle.

In this paper we discuss the rational for introducing multiple, dynamic, display windows into today's thermal imaging systems to provide greatly improved image analysis capabilities in all thermographic applications. Combining dynamic windows with high resolution images allow the User to view a full optical field-of-view and specific areas of interest simultaneously. These specific areas are defined by the User and then may be optically magnified, resized and placed anywhere on the display screen. Up to 16 dynamic windows may be viewed in color, grey scale, reverse grey, Delta (real time image subtraction), or in any combination. Individual windows may be placed in a hold mode, or stored and recalled, while observing other windows constantly being updated. The User has the ability to view the entire field-of-view and specific areas of interest within the FOV at the same time. The addition of shape analysis allows the User to outline, or select from a library of shapes, and monitor these selected areas within individual windows. The system would then calculate and display the high, low, and average temperature of defined areas, a histogram, or an analog gradient for each area within a window. All such graphs or tables may also be place anywhere on the screen.