Thermosense XXXI

Conference 7299 – Proceedings of SPIE Volume 7299
Dates: Tuesday-Wednesday 14 - 15 April 2009
Part of program track on IR Sensors and Systems
Conference Chairs
Douglas D. Burleigh, La Jolla Cove Consulting; Ralph B. Dinwiddie, Oak Ridge National Lab.

Program Committee
Nicolas P. Avdelidis, National Technical Univ. of Athens (Greece); Jeff R. Brown, Hope College; Pierre G. Bremond, Cedip Infrared Systems (France); Antonio Colantonio, Public Works and Government Services Canada (Canada); Fred P. Colbert, Colbert Infrared Services; K. Elliott Cramer, NASA Langley Research Ctr.; Viki L. DeMars, Professional Thermographers Association; Ermanno G. Grinzato, Consiglio Nazionale delle Ricerche (Italy); Sheng-Jen Hsieh, Texas A&M Univ.; Herbert Kaplan, Honeyhill Technical Co.; Timo T. Kauppinen, VTT (Finland); Kathryn M. Lee, United Space Alliance, LLC; Dennis H. LeMieux, Siemens Corporate Research; Robert P. Madding, FLIR Systems, Inc.; Xavier P. V. Maldague, Univ. Laval (Canada); Jonathan J. Miles, James Madison Univ.; Gary L. Orlove, FLIR Systems, Inc.; G. Raymond Peacock, Temperatures.com, Inc.; Piotr Pregowski, Pregowski Infrared Services (Poland); Andrés E. Rozlosnik, SI Termografía Infrarroja (Argentina); Morteza Safai, The Boeing Co.; Takahide Sakagami, Osaka Univ. (Japan); R. James Seffrin, Infraspection Institute; Steven M. Shepard, Thermal Wave Imaging, Inc.; Gregory R. Stockton, Stockton Infrared Thermographic Services, Inc.; Vladimir P. Vavilov, Tomsk Polytechnic Univ. (Russia); Lisa West Åkerblom, FLIR Systems AB (Sweden)

Monday 13 April

Vendor Presentations and Reception

Date: Monday 13 April
Time: 5:00 PM – 8:00 PM
This event features brief presentations from hardware and software vendors on what is new this year in their product lines that impact thermal imaging applications and practices.

What’s News in Hardware and Software at the 2009 DSS Exhibition? This Special Session was started four years ago and has been a very popular, well-attended success. Its intent is to bring together vendors and early arrival Thermosense and DSS exhibitors to highlight the newest products and services being shown at the Exhibition. In this way, the busy technical conference attendees can better prioritize their activities when visiting the exhibits.

It is also a relaxed opportunity for getting to know one another better and to have informal discussions on matters of mutual interest. A limited time for 10- to 15-minute vendor presentations starts the session, followed by a reception with snacks and soft drinks. The list of vendors presenting will be in the final program and also available on-site.

Your company must be an exhibitor at DSS09 to be part of this event. If you are interested in participating, or have more questions, please contact:

G. Raymond Peacock: rpeacock [at] temperatures.com
or Herbert Kaplan: hkaplan [at] earthlink.net

Tuesday 14 April

Session 1:  Calibration and Radiometric Measurements

Date: Tuesday 14 April
Time: 8:00 AM – 9:00 AM
Session Chairs: G. Raymond Peacock, Temperatures.com, Inc.; Robert P. Madding, FLIR Systems, Inc.; Ralph B. Dinwiddie, Oak Ridge National Lab.

Characterization of thermal imagers under various ambient conditions

Paper 7299-1
Author(s): Riho Vendt, Priit Jaanson, Viktor Vabson, Toomas Kübarsepp, Metrosert AS (Estonia); Mart Noorma, Tartu Ülikool (Estonia)

Calibration of conventional thermal imagers at various controlled environmental conditions is important in order to account for the influence of the ambient environment on the measurement result. In this paper, calibration of different commercial thermal imagers in a climatic chamber is described. The simulated ambient temperature range from -20°C to +30°C has been used at calibrator temperatures between -15°C and +50°C. The effect of the variable ambient temperatures on the metrological properties of the thermal imagers is discussed and their contribution to the measurement uncertainty is evaluated.

Improving scene-based nonuniformity correction for infrared images using frequency domain processing

Paper 7299-2
Author(s): Jonah C. McBride, Magnus S. Snorrason, Charles River Analytics, Inc. (United States)

Scene Based Non-Uniformity Correction (SBNUC) is an attractive alternative to radiometric calibration for infrared sensors because it does not rely on specialized hardware. The best known approach is Constant Statistics (CS) but it is highly dependent on scene content and the amount of motion present, often introducing a “ghosting” artifact. In this paper, we present a novel approach which applies a variation on CS to both the spatial and frequency domains of the image. The result is a solution which effectively eliminates fixed pattern noise without ghosting and is much less dependant scene content and scene motion than traditional CS.

High-heat flux sensor for infrared thermography determination of heat-transfer coefficient of liquid metal-cooled target’s wall

Paper 7299-3
Author(s): Jacek A. Patorski, Paul Scherrer Institut (Switzerland); Malko Gindrat, Sulzer Metco AG (Switzerland)

The proton beam passing through container wall area of liquid metal (LM) target, called entrance window, is causing high heat flux of 140 W/cm2. Previous experimental thermo-hydraulics investigations of Heat-Transfer-Coefficient for LM-target using InfraRed-Thermography (IRT) have been presented at Thermosense-2006-7. They used IRT-sensors with low heat fluxes 15 W/cm2. Because of positive effect of heat flux buoyancy on cooling, the idea for High Heat Flux (HHF) IRT Sensors, using of the Low-Pressure-Plasma-Spraying technology of the Firm Sulzer Metco has been created. The paper presents multilayer sprayed construction of HHF-IRT-Sensor and results of LM thermo-hydraulics-tests of sensors using the 2DD-IRT-methodology.

Symposium-Wide Plenary Presentation

Date: Tuesday 14 April
Time: 9:00 AM – 10:00 AM

Re-engineering Engineering (Presentation Only) (Plenary)

Paper DSS09SE-100
Author(s): Norman Augustine, Ret. Chairman & Chief Executive Officer, Lockheed Martin Corp. (United States)

Session 2:  Biological and Medical Applications

Date: Tuesday 14 April
Time: 10:30 AM – 11:10 AM

Session Chairs: Morteza Safai, The Boeing Co.; Gary L. Orlove, FLIR Systems, Inc.; Ralph B. Dinwiddie, Oak Ridge National Lab.

Infrared imaging to quantify the effects of nicotine-induced vasoconstriction in humans

Paper 7299-4
Author(s): Siegfried Brunner, Christian Kargel, Univ. der Bundeswehr München (Germany)

Smoking causes many adverse health effects including the constriction of blood vessels. We used infrared imaging to quantify temperature decreases in the extremities of smokers caused by vasoconstriction. Surprisingly, in our non-smoking control persons we found temperature increases suggesting that the cigarettes provoked vasodilation. To verify this unexpected finding we administered nicotine (2 mg, chewing gum) to smokers and non-smokers following a stringent experimental protocol. Task-optimized digital image processing was developed to automatically yield temperature plots from the acquired thermograms. The results will be presented in detail showing that smokers and non-smokers indeed respond differently to the administration of nicotine.

Face detection in thermal imagery using an Open Source Computer Vision Library

Paper 7299-5
Author(s): Sarun Sumriddetchkajorn, Armote Somboonkaew, National Electronics and Computer Technology Ctr. (Thailand)

This paper studies the use of a combination of Haar-like features and a cascade of boosted tree classifiers embedded in a widely used Open Source Computer Vision library, known as OpenCV, for face detection in thermal images. With 2013 positive and 2020 negative 320×240-pixel thermal images for 20 training stages on three window sizes of 20×20, 24×24, and 30×30 pixels, our experiment shows a promising result of deploying the OpenCV for face detection in thermography-based mass human temperature screening and deceptive detection systems. Key issues will be discussed.

Session Chairs: Timo T. Kauppinen, VTT (Finland); Gregory R. Stockton, Stockton Infrared Thermographic Services, Inc.; Nicolas P. Avdelidis, National Technical Univ. of Athens (Greece)

Measurement of wind speed from cooling lake thermal imagery

Paper 7299-9
Author(s): Alfred J. Garrett, Savannah River National Lab. (United States) and Rochester Institute of Technology (United States); Eugene P. Shine, Richard C. Tuckfield, Eliel Villa-Aleman, Robert J. Kurzeja, Malcolm M. Pendergast, Timothy B. Brown, Savannah River National Lab. (United States)

The Savannah River National Laboratory (SRNL) and Clemson University are collaborating in a Department of Energy (DOE) sponsored project to determine the applicability to cooling lakes of laboratory empirical correlations between basic quantities such as surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that there is also a functional relationship between the skewness of the temperature distribution derived from cooling lake thermal images and the instantaneous wind speed measured at the same location.

Use of remote sensing data to enhance the performance of a hydrodynamic simulation of a partially frozen cooling lake utilized in power plant efficiency studies

Paper 7299-10
Author(s): May V. Arsenovic, Carl Salvaggio, Edward C. Hensel, Rochester Institute of Technology (United States); Alfred J. Garrett, Savannah River National Lab. (United States) and Rochester Institute of Technology (United States)

The thermodynamic and hydrodynamic analysis of a cooling lake can become significantly more complex when a power generation site is located in a northern climate. Once a lake is partially or fully frozen, the predictive capabilities of a hydrodynamic model are weakened due to an insulating surface layer of ice and snow. Thermal imagery of a cooling pond was collected over a period of approximately 16 weeks in tandem with high-density thermal measurements both in open water and imbedded in ice, meteorological data, and snow layer characterization data. This work describes a method to employ thermal imagery to improve the performance of a 3-D hydrodynamic model of a power plant cooling pond in the presence of ice and snow.

Seismic risk evaluation aided by IR Thermography

Paper 7299-11
Author(s): Ermanno G. Grinzato, Consiglio Nazionale delle Ricerche (Italy)

Session 5:  Industrial Applications and Research Topics

Date: Tuesday 14 April
Time: 2:30 PM – 5:40 PM
Session Chairs: Kathryn M. Lee, United Space Alliance, LLC; Herbert Kaplan, Honeyhill Technical Co.; Jonathan J. Miles, James Madison Univ.

Electronic hidden solder-joint geometry characterization

Paper 7299-12
Author(s): Sheng-Jen Hsieh, Texas A&M Univ. (United States)

This paper investigates an active thermography approach to probing printed circuit board solder joint geometry. A semi-automated system was built to heat and then transfer identical boards to a chamber where an infrared camera was used to scan each board as it was cooling down. Two-thirds of the data was used for model development and one-third for model evaluation. Joints with greater surface area cooled much faster than joints with less surface area. The approach and models can potentially be used to test for cold solder joints prior to BGA assembly, since these joints may have relatively slow cooling rates.

U-value estimation on refrigerated vehicles by thermographic analysis

Paper 7299-13
Author(s): Stefano Rossi, Ermanno G. Grinzato, Paolo Bison, Sergio Marinetti, Consiglio Nazionale delle Ricerche (Italy)

IR thermography is joined to a thermal model for evaluating thermal performance of insulated containers. The method is illustrated with experimental results obtained into a test tunnel working under controlled environmental conditions. Insulated vehicles are tested in parallel according to the accepted standard “Agreement on the international carriage of perishable fo odstuff” (ATP) and the thermographic method. A thermographic apparatus is used to localize thermal bridges and to determine the surface temperatures within the affected areas.
The proposed thermographic method allows also determining of air leaks magnitude and location. These results are important in order to enhance manufacture.
Some experimental data are presented in order to compare U- values measured along ATP rules and calculated by the faster thermographic inspection. The comparison allows verifying the accuracy.
Such a quality test is particularly useful for periodic control of insulation ageing.

Heating medium absorption and emission as factors of thermographic investigations of petrochemical furnaces

Paper 7299-14
Author(s): Piotr Pregowski, Pregowski Infrared Services (Poland); Grzegorz Goleniewski, Wojciech Komosa, Waldemar A. Korytkowski, PKN ORLEN S.A. (Poland); Slawomir Zwolenik, neoVISION (Poland)

This paper presents the current state of our efforts to increase efficiency of petrochemical plant with using dynamic, multispectral-band IR radiation thermometry. Depending on the type of investigations i.e. studying tubes’ temperature, or studying energetic and dynamic features of the flames and flue gases, different narrow-band optical filters and research procedures have to be applied. To perform both type of these measurements we modernised commercial PtSi FPA camera and software. Two of results are highligted: possibilities to increase tube’ temperature measurements confident and reliability, as well as a new diagnostic potential of the images of chosen gases features, for comparative investigations in partucular.

Characterization of uncertainties when measuring metal cutting temperatures using infrared radiation thermography

Paper 7299-15
Author(s): Eric Whitenton, National Institute of Standards and Technology (United States)

There are many error sources when using infrared radiation thermography to measure the temperature distribution of the tool, workpiece, and chip during metal cutting. It is important to understand how these error sources affect the measurement uncertainty. Some are familiar to anyone performing thermography measurements, such as uncertainties in the basic camera calibration. However, metal cutting presents unique measurement challenges due to factors such as the high magnification required, high surface speeds, polarization effects, micro-blackbody effects, and changing emissivity as chips form. This paper presents the current state of our efforts to catalog and characterize error sources and resulting uncertainties.

The use of microscopes and telescopes in thermography

Paper 7299-16
Author(s): Ralph B. Dinwiddie, Oak Ridge National Lab. (United States)

A wide selection of lenses is very useful to the thermographer working in a research environment, where applications can vary from week to week. Both wide angle and telephoto infrared lenses are widely used alternatives to the standard lenses typically supplied by IR camera manufacturers. However, in some extreme applications the need arises for additional image magnification. In these cases, the thermographer must rely on an IR microscope for close-up work on the order of millimeters, or a telescope for working at a distance on the order of meters or kilometers. Example applications using an IR microscope and reflecting telescope will be discussed, as well as the challenges and characteristics of using these instruments.

Target recognition: fusing LWIR and EO imagery for detection of humans in a scene

Paper 7299-17
Author(s): Renee L. Woodyard, Julie A. Skipper, Wright State Univ. (United States); Daniel W. Repperger, Air Force Research Lab. (United States)

Fusion of long-wave infrared (LWIR) and electro-optical (EO) imagery can increase the accuracy of target recognition algorithms, particularly when the task is to detect humans in a scene. We simulate human body heat flow both between tissue layers and body segments. Inputting ambient temperature and humidity, body mass index, activity level and clothing allows us to predict the range of human skin emissivity and eliminate thermal clutter. Manipulating these parameters shows their effects on the ability to differentiate humans from their surroundings under various environmental conditions. Finally, feature-level fusion of the deblurred LWIR and EO images facilitates identity declaration.

NIR applications in electronics and medical technology

Paper 7299-18
Author(s): Leino Mirka, Huhtanen Jukka, Lähdeniemi Matti, Soini Antti, Satakunta Univ. of Applied Sciences (Finland)

Rapid detection of sugar content and pH in red wines based on projection pursuit regression

Paper 7299-19
Author(s): Fang G. Wu, Zhejiang Univ. (China)

Vis/NIR spectra of red wines were obtained by spectral transmission scan, one mixed algorithm of partial least squares (PLS) and projection pursuit regression (PPR) was presented to predict sugar content and pH of red wines. processed the original spectral data using partial least squares (PLS), selected 6 best latent variables (LVs) based on the reliabilities would be taken as the input of the projection pursuit regression (PPR). Trained the PPR with samples in calibration collection and predicted the samples in prediction collection. The result indicted that the red wines internal quality such as sugar content and pH detected by Vis/NIR spectra technology was very feasible and laid a solid foundation for setting up the sugar content forecasting model of wines and beverages.

Application of wavelet threshold denoising model to infrared spectral signal processing

Paper 7299-20
Author(s): Fang G. Wu, Zhejiang Univ. (China)

Abstract: Aim at noise interference of infrared spectra, An example of using infrared spectral to detect fat value on the surface of cashmere were applied to evaluate the effect of wavelet threshold de-noising. The de-noising capabilities of three wavelet threshold de-noising models (Penalty threshold de-noising model, Brige-Massart threshold de-noising model and Default threshold de-noising model) were compared and analyzed. De-noised spectral and measured cashmere fat values were used for calibration and validation with multivariate analysis (Partial Least Squares combined with Support Vector Machine), The results show that wavelet threshold de-noising models can de-noise infrared spectral signal effectively, make multivariate analysis model of spectral data and measured cashmere fat values more representatively and robust, and so as to it can raised detection precision of infrared spectral technique.

Wednesday 15 April

Session 6:  Materials Evaluation

Date: Wednesday 15 April
Time: 8:00 AM – 8:40 AM
Session Chairs: Takahide Sakagami, Osaka Univ. (Japan); Ermanno G. Grinzato, Consiglio Nazionale delle Ricerche (Italy)

Thermograms analysis for process physics visualization, using 3D temperature profiles (Presentation Only)

Paper 7299-21
Author(s): Mohammed A. Omar, Yi Zhou, Clemson Univ. (United States)

This work discusses the use of real-time industrial thermograms, to predict the stress concentration of metallic surfaces. The work presents two case studies with different governing equations for the temperature generation and distribution; heat generation due to plastic deformation and the thermo-elasticity. The first case study covers the monitoring of the stamping die wrinkling pressure using infrared sequences, to detect splits and metal tears onsite. While the second case study discusses the implementation of thermo-elasticity analysis coupled with a thermography setup to evaluate the stress levels in the heat affected zone of a welded joint. The work will present the calculations for the pre and post-processing algorithms to neutralize the emissivity contribution, account for lateral heat diffusion and detect thermal abnormalities, which include new concepts of dynamic template processing.

Influence of a growing oxide layer on band-emissivities used for optical termperature measurements

Paper 7299-40
Author(s): Wolfgang Bauer, Alexander Moldenhauer, Univ. Duisburg-Essen (Germany)

It is well known that the spectral emissivities of metal surfaces can be changed remarkable by growing oxide layers. This effect influences the optical temperature measurement when pyrometer or IR-cameras are working in the same wavelength ranges. The changes of spectral emissivities also leads to changes of the band-emissivities used as values for emissivity correction of the optical temperature instruments. Primarily, these effects depend only on emissivity and can occur without changes of metal’s temperature.

Session 7:  IR NDT I: Theory

Date: Wednesday 15 April
Time: 8:40 AM – 12:20 PM
Session Chairs: Douglas D. Burleigh, La Jolla Cove Consulting; Vladimir P. Vavilov, Tomsk Polytechnic Univ. (Russian Federation); Steven M. Shepard, Thermal Wave Imaging, Inc.

Load-induced debonding of FRP composites applied to reinforced concrete

Paper 7299-24
Author(s): Joel Blok, Jeff R. Brown, Hope College (United States)

FRP composites are used to strengthen reinforced concrete elements. Strengthened surfaces are no longer visible and delamination resulting from excessive loading or fatigue may go undetected. This research investigated IRT techniques for evaluating delamination of FRP composites applied to small scale RC beams. Four small-scale beams were loaded either monotonically or cyclically to failure. IRT inspections were performed at increments through failure using a composite phase imaging technique. Individual phase values for each pixel were categorized and progressive FRP debonding was monitored. This research outlines a proposed methodology for data collection and analysis that can be used to assess the overall health of an FRP repair and to predict remaining service life.

Application of air-coupled acoustic thermography (ACAT) for inspection of honeycomb structures

Paper 7299-25
Author(s): Joseph N. Zalameda, Army Research Lab. (United States); William P. Winfree, NASA Langley Research Ctr. (United States); Charles G. Pergantis, David Flanagan, Daniel DeSchepper, Army Research Lab. (United States)

The application of a noncontact air coupled acoustic heating technique is investigated for the inspection of advanced honeycomb composite structures. A weakness in the out of plane stiffness of the structure, caused by a delamination or core damage, allows for the coupling of acoustic energy and thus this area will have a higher temperature than the surrounding area. Air coupled acoustic thermography (ACAT) measurements were made on composite sandwich structures with damage and were compared to conventional flash thermography. A vibrating plate model is presented to predict the optimal acoustic source frequency. Improvements to the measurement technique are also discussed.

Advances in frequency modulated thermal wave imaging for noncontact subsurface sensing

Paper 7299-26
Author(s): Ravibabu Mulaveesala, Venkata Subba Rao Ghali, Nataraj Jonnalagadda, Indian Institute of Information Technology (India); Suneet Tuli, Indian Institute of Technology Delhi (India)

Increased demand for greater depth of probing in InfraRed Thermography (IRT) is often thwarted by the requirement of high speed IR cameras and very high peak power heat sources. Present work highlights a correlation based pulse compression approach, offers a means of increasing average power available to illuminate test specimen without any loss of the depth resolution needed for the tactical requirements. This is accomplished by adopting correlation based pulse compression on the captured temperature data, during active frequency modulated heating. This leads to a time compression of the received signal to a much narrower pulse of high effective peak power. For the demonstration, a mild steel sample having flat bottom holes at various depths is introduced and detection capability of the proposed correlation based approach has been studied.

Measurement limits in active thermography

Paper 7299-27
Author(s): Steven M. Shepard, Yulin Hou, James R. Lhota, Tasdiq Ahmed, Thermal Wave Imaging, Inc. (United States)

Although active thermography has traditionally been regarded as a qualitative NDT method, its potential for quantitative measurement of thermophsyical properties including wall thickness, flaw size and depth, thermal diffusivity or effusivity has been the subject of numerous investigations. However, given the diffusion mechanism that underlies thermography, there are hard limits to what can be achieved in a thermography measurement. While many benefits can be achieved with improved instrumentation, efficient energy insertion or optimized signal processing, ultimately, the limits imposed by diffusion take precedence, and cannot be circumvented. For a given thermography system, a set of criteria can be established to determine the spatial and temporal limits of measurement and detectability.

Enhanced contrast detection of subsurface defects by pulsed infrared thermography based on the fourth order statistic moment: kurtosis

Paper 7299-28
Author(s): Francisco J. Madruga, Univ. de Cantabria (Spain); Clemente Ibarra-Castanedo, Univ. Laval (Canada); Olga M. Conde, Univ. de Cantabria (Spain); Xavier P. V. Maldague, Univ. Laval (Canada); José M. López-Higuera, Univ. de Cantabria (Spain)

In this paper, an algorithm based on the fourth order standardised statistic moment, i.e. kurtosis, is proposed for detection and/or characterization of subsurface defects having a thermal diffusivity either higher or lower than the hosted material. All the information is contained in a single image allowing to discriminate between the defect types (higher o lower diffusivity than the hosted material). Processed results using synthetic and experimental data with other methods used in the field of Thermography for defect detection and/or characterization are provided as well for comparison.

Characterizing defects in pulsed thermal NDT

Paper 7299-29
Author(s): Vladimir P. Vavilov, Tomsk Polytechnic Univ. (Russian Federation)

This study is devoted to pulsed thermal NDT of both metals and non-metals (composites), in particular, to the characterization of subsurface defects. The determination of defect depth, thickness and lateral size is discussed along with the achievable accuracy. It is shown than most available defect characterization algorithms are essentially one-dimensional being based on the analysis of heat conduction in uniform and multi-layer structures. The approach to three-dimensional evaluation of defect parameters developed at Tomsk Polytechnic University is presented.

Heat-stimulus correction for pulsed-infrared thermography

Paper 7299-31
Author(s): Hernan D. Benitez Restrepo, Pontificia Univ. Javeriana, Cali (Colombia); Abdelhakim Bendada, Clemente Ibarra-Castanedo, Xavier P. V. Maldague, Univ. Laval (Canada)

The modified DAC version with thermal quadrupoles can be considered an interesting alternative to thermal contrast computations since it provides an automated tool for depth retrieval and eliminates the need of selecting a non-defective area. In practice it is important to have heat stimulus with complex shapes and long durations (several seconds) in order to cover larger inspection areas, enhance thermal contrast between defective and sound areas and increase the depth of inspection inside the material. In this work we present a heat stimulus correction by using the thermal quadrupoles theory and its validation with several heat stimulus shapes and durations.

Thermography as a non-invasive and automated NDE approach for composites assessment

Paper 7299-23
Author(s): Nicolas P. Avdelidis, Maria Koui, National Technical Univ. of Athens (Greece)

Smart methods for assessing the integrity of a composite structure are essential to both reduce manufacturing costs and out of service time of the structure due to maintenance. Certain applications of transient thermal NDT relating to the assessment of composites are presented and discussed. By using automated and advanced non-invasive thermography tools for the inspection of composites there will be a reduction in the use of manual, subjective inspections. It will also improve sensitivity for the detection of small defects. This way, accuracy is improved, leading to an increased “Probability of Detection” at a higher confidence level.

Autonomous infrared thermography based inspection of glass-reinforced plastic (GRP) wind turbine blades (WTBS)

Paper 7299-30
Author(s): Charalampos Schizas, Panagiotis Chatzakos, Alexandros Lagonikas, Dimitrios Korres, Nikolaos Avdelidis, Vasilios Spais, Kostas Chryssagis, ZENON S.A. (Greece)

In this paper, the development of an autonomous,novel and lightweight multi-axis scanning system, deploying in-situ Infra Red Thermography (IRT) based Non Destructive Testing (NDT), on glass reinforced plastic (GRP) wind turbine blades (WTBs), is presented. The scanner incorporates an intrinsic multi-degree-of-freedom (DOF) end-effector able to comply and achieve successful adjustment on the complex contours of a WTB, automatically aligning at the same time, the IRT equipment in proper position for inspection.

Lunch/Exhibition Break

12:20 PM – 1:30 PM

Session 8:  IR NDT II: Applications

Date: Wednesday 15 April
Time: 1:30 PM – 4:50 PM
Session Chairs: Douglas D. Burleigh, La Jolla Cove Consulting; Jeff R. Brown, Hope College; K. Elliott Cramer, NASA Langley Research Ctr.

Thermographical investigations of inductively heated metallic surfaces

Paper 7299-32
Author(s): Beate Oswald-Tranta, Mario Sorger, Montan Univ. Leoben (Austria)

Thermo-inductive investigations can be used for the detection of surface cracks in metallic materials. The work-piece is heated by a short inductive pulse and an infrared camera is recording the temperature distribution of the surface. Irregularities and failures in the surface cause anomalies in the temperature distribution, making the failures visible. Model calculations have been carried out in order to describe the distribution of the eddy current around a surface crack and to calculate the resulting temperature profile around it. The time-dependent evaluation of the temperature provides results which are independent of the emissivity differences and therefore shows also very well-defined results in the case of grinded or scratched surfaces. This technique has been used for a couple of different work-pieces presenting its advantages.

Thermographic detection of near-surface flaws in reinforced carbon-carbon panels (Invited Paper) /em>

Paper 7299-33
Author(s): William P. Winfree, Patricia A. Howell, NASA Langley Research Ctr. (United States)

Thermographic inspection is a viable technique for detecting in-service damage in reinforced carbon-carbon (RCC) composites that are used for thermal protection in the leading edge of the Space Shuttle. A significant advantage of thermography is the ability to provide a rapid, noncontacting, full field imaging, single-sided inspection that can be performed between flights without removing the RCC panels from the vehicle. This paper presents an assessment of a thermographic technique for detection of near surface flaws in RCC composite structures.

Development of thermographic inspection routine exploiting phase transition of water for moisture detection in aircraft structures

Paper 7299-34
Author(s): Eetta Saarimäki, VTT Technical Research Ctr. of Finland (Finland); Peter Ylinen, Finnish Air Force (Finland)

Penetrated water in the composite sandwich structures has caused problems in aircraft structures. Thermographic investigation is done to find a suitable procedure to find penetrated water from the composite aircraft structures by cooling the whole structure, or separated parts of the aircraft, under freezing conditions. Thermographic inspection based on the phase transition of water exploits the phase transition energy that is needed for the water defrosting. Aircraft can be either inspected right after a flight, or it can be left outside in freezing conditions overnight and inspected when it has been brought in to the maintenance hall to warm conditions.

Application of infrared imaging for quality inspection in resistance spot welds

Paper 7299-35
Author(s): Wanchuck Woo, Hsin Wang, Zhili Feng, Hanbing Xu, Charles Chin, Oak Ridge National Lab. (United States)

To develop a non-destructive inspection technique in the automotive production environment, the infrared imaging method was applied for the instant quality determination of resistance spot welds (RSW). We prepared 10 sets of desirable and undesirable quality steel RSW with different welding parameters and examined the welding quality using infrared camera. By monitoring the heat conduction through the weld nugget under four different heating and cooling conditions, we established a direct correlation between the welding quality and the “thermal signature” of each weld. Moreover, these imaging results will be compared to the microstructure and finite element modeling results.

Nondestructive testing by superresolution infrared thermography

Paper 7299-36
Author(s): Takahide Sakagami, Shiro Kubo, Tomohiro Matsumoto, Osaka Univ. (Japan); Daisuke Sato, Constec Engineering Co., Ltd. (Japan)

Super-resolution techniques were applied for infrared thermographic temperature measurement for the improvement of spatial resolution of the infrared camera with limited number of imaging pixels. The super-resolution technique was developed based on the movement compensation analyses by the digital image correlation and reassignment of the pixel values. Developed super-resolution infrared thermography was applied for the defect measurement in concrete structures demonstrating the usefulness of the present technique.

Thermographic evaluation of artworks

Paper 7299-37
Author(s): Steven M. Shepard, Thermal Wave Imaging, Inc. (United States); Jim Coddington, The Museum of Modern Art (United States); Yulin Hou, James R. Lhota, Tasdiq Ahmed, Thermal Wave Imaging, Inc. (United States)

In recent years infrared imaging has been recognized as a useful tool in art conservation, and in evaluation of paintings, in particular. It offers considerable insight into the construction of a work of art, the materials the artist or subsequent restorers may have used, and generally the creative development of the work, and does not require contact, immersion or even close proximity to the piece. Efforts to date have typically involved either 1) passive imaging in the near-infrared spectrum for viewing of residual sketch marks or signatures hidden under paint, or 2) spectral imaging using active sources and narrow band filters, to identify specific paint media and pigments. Additional information can be extracted using flash thermography. Operating at very low energies, the resulting data yields both instantaneous reflected IR data, as well as a time history for each pixel, that can be analyzed using the Thermographic Signal Reconstruction (TSR) method. The reflected component indicates the opacity of the pigment, while the derivatives of the time history indicate the local paint thickness and the boundary condition at the canvas. Taken together, these components can be used to define unique signature for various pigment-medium combinations.

Applying infrared thermography to marine surveying

Paper 7299-38
Author(s): John N. Allinson II, J.N. Allinson Associates, Inc. (United States)

Marine surveyors are to the marine industry as building and home inspectors are to the commercial and residential real estate industry. A marine surveyor’s opinions are relied upon to document the condition and value of the vessels (boats, ships) they inspect. A marine surveyor examining a vessel relies heavily upon experience and what can be seen, heard, and felt. Traditionally, visual anomalies seen with the unaided eye often are the sole basis for further testing. Infrared images are an effective tool in extending a marine surveyor’s ability to detect anomalies. This paper describes the use of the infrared thermal imaging to inspect structural, mechanical, and electrical systems on boats. It will review common deficiencies found in vessels and show how infrared thermal imaging has become an effective tool in documenting findings during inspections.

Euclidean distance algorithm for defect recognition in infrared thermographic nondestructive testing

Paper 7299-39
Author(s): Xingwang Guo, Qidalatu Wang, BeiHang Univ. (China)