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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Infrared imaging: a proposed validation technique for computational fluid dynamics codes used in STOVL applications

Hardman, Robert R. 02 May 2009 (has links)
The need for a validation technique for computational fluid dynamics (CFD) codes in STOVL applications has led to research efforts to apply infrared thermal imaging techniques to visualize gaseous flow fields. Specifically, a heated, free-jet test facility was constructed. The gaseous flow field of the jet exhaust was characterized using an infrared imaging technique in the 2 to 5.6μm wavelength band as well as conventional pitot tube and thermocouple methods. These infrared images are compared to computer-generated images using the equations of radiative exchange based on the temperature distribution in the jet exhaust measured with the thermocouple traverses. Temperature and velocity measurement techniques, infrared imaging, and the computer model of the infrared imaging technique are presented and discussed. From the study, it is concluded that infrared imaging techniques coupled with the radiative exchange equations applied to CFD models are a valid method to qualitatively verify CFD codes used in STOVL applications. / Master of Science
62

Infrared face recognition

Lee, Colin K. 06 1900 (has links)
Approved for public release, distribution is unlimited / This study continues a previous face recognition investigation using uncooled infrared technology. The database developed in an earlier study is further expanded to include 50 volunteers with 30 facial images from each subject. The automatic image reduction method reduces the pixel size of each image from 160 120 to 60 45 . The study reexamines two linear classification methods: the Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (LDA). Both PCA and LDA apply eigenvectors and eigenvalues concepts. In addition, the Singular Value Decomposition based Snapshot method is applied to decrease the computational load. The K-fold Cross Validation is applied to estimate classification performances. Results indicate that the best PCA-based method (using all eigenvectors) produces an average classification performance equal to 79.22%. Incorporated with PCA for dimension reduction, the LDA-based method achieves 94.58% accuracy in average classification performance. Additional testing on unfocused images produces no significant impact on the overall classification performance. Overall results again confirm uncooled IR imaging can be used to identify individual subjects in a constrained indoor environment. / Lieutenant, United States Navy
63

Rainfall estimation from satellite infrared imagery using artificial neural networks

Hsu, Kuo-Lin, Sorooshian, Soroosh, Gao, Xiaogang, Gupta, Hoshin Vijai January 1997 (has links)
Infrared (IR) imagery collected by geostationary satellites provides useful information about the dirunal evolution of cloud systems. These IR images can be analyzed to indicate the location of clouds as well as the pattern of cloud top temperatures (Tbs). During the past several decades, a number of different approaches for estimation of rainfall rate (RR) from Tb have been explored and concluded that the Tb-RR relationship is (1) highly nonlinear, and (2) seasonally and regionally dependent. Therefore, to properly model the relationship, the model must be able to: (1) detect and identify a non-linear mapping of the Tb-RR relationship; (2) Incorporate information about various cloud properties extracted from IR image; (3) Use feedback obtained from RR observations to adaptively adjust to seasonal and regional variations; and (4) Effectively and efficiently process large amounts of satellite image data in real -time. In this study, a kind of artificial neural network (ANN), called Modified Counter Propagation Network (MCPN), that incorporates these features, has been developed. The model was calibrated using the data around the Japanese Islands provided by the Global Precipitation Climatology Project (GPCP) First Algorithm Intercomparison Project (AIP-I). Validation results over the Japanese Islands and Florida peninsula show that by providing limited ground-truth observation, the MCPN model is effective in monthly and hourly rainfall estimation. Comparison of results from MCPN model and GOES Precipitation Index (GPI) approach is also provided in the study.
64

Propagation and performance analysis for a 915 MHz wireless IR image transfer system / Propagation and performance analysis for a 915 MHz wireless infrared image transfer system

Felekoglu, Oktay. 06 1900 (has links)
A 915 MHz wireless IR image transfer system, comprised of an IR-160 Thermal Camera and MDS iNet 900 transceivers, was assessed for image transfer capabilities in different environments. Image transfer through natural and artificial obstructions, the capability of transferring images under urban environments, and an exploration of interference issues associated with RF communication links were investigated in detail. Concrete, wood, various construction materials, and building walls were examined to assess indoor propagation capabilities. Data transmission through random trees, buildings, foliage under various atmospheric conditions is also evaluated for outdoor system capabilities. A maximum free space range for acceptable IR image transferring is determined as 23 miles for line of sight (LOS). Non line of sight (NLOS) urban environment measurements revealed that urban path loss (15-60 dBm) is highly dependent on antenna orientation and obstruction geometry rather than the T-R separation distance.
65

Delivery of Myoglobin Polymersomes Results in Tumor Hemorrhagic Necrosis and Enhanced Radiation Response

Hofmann, Christina Lehmkuhl January 2015 (has links)
<p>There is a critical need to target tumor hypoxia as patients with hypoxic tumors have worse prognosis due to aggressive phenotypes and resistance to radiotherapy and chemotherapy. The overall goal of this work is to improve response to conventional cancer therapies by targeting tumor hypoxia. This has been carried out and evaluated through the use of polymersome-encapsulated myoglobin (PEMs) with the hypothesis that O2-releasing PEMs will increase tumor oxygenation, and thereby improve response to radiotherapy. Mb was chosen as an O2 carrying protein to deliver to tumors because it has a strong association to O2, providing a mechanism to deliver O2 only within the hypoxic regions of the tumor. Mb was loaded within nanoscale polymeric vesicles that were expected to accumulate within solid tumors due to the enhanced permeability and retention (EPR) effect. This hypothesis has been tested through the following aims:</p><p>1. Develop NIR imaging techniques for studying the biodistribution and pharmacokinetics of polymersomes</p><p>2. Establish the effects of Mb-containing polymersomes on tumor physiology</p><p>3. Modify tumor growth through delivery of Mb polymersomes in combination with a cytotoxic therapy specific to aerobic tumors</p><p>These aims have been evaluated through numerous in vivo studies. First, polymersomes of various polymer formulations and diameters ranging from 110-550 nm were prepared with a near-infrared (NIR) -emissive fluorophore. Using live animal fluorescence imaging, I was able to study the biodistribution of the polymersomes following i.v. administration, demonstrating significant polymersome accumulation in orthotopic 4T1 mammary carcinomas. In addition, a novel method for measuring pharmacokinetics was developed, using serial small volume blood draws from individual mice. The plasma fluorescence in microcapillary tubes was used to quantify polymersome concentrations, demonstrating long circulation half-lives that varied from 6-23 h. Toxicity of various polymersome formulations were also studied in vitro and in vivo, revealing negligible toxicities.</p><p>For the second aim, PEMs were administered i.v. in tumor-bearing mice. Unexpectedly, we observed a dramatic gross tumor effect within hours of treatment in both orthotopic 4T1 tumors and flank Renca renal cell carcinomas. Histological analysis revealed endothelial cell apoptosis as early as 1 h following treatment, with scattered tumor cell death throughout the tumor by 4 h. Hematoxylin and eosin staining showed significant necrosis 24 h following PEM treatment. Vascular effects and polymersome distribution were studied in 4T1 window chamber tumors. Following i.v. treatment with PEMs, intravital microscopy was used to image polymersome fluorescence, brightfield transmission was imaged for vessel morphology and blood flow, and a tunable filter was used for determining hemoglobin (Hb) oxygen saturation. Tumor hemorrhaging was observed within hours of PEM treatment, which was not seen with empty polymersomes. This was consistent with the gross tumor effects observed initially. Hb saturation decreased in both the PEM and empty polymersome groups, but not in saline-treated mice. While we expected to observe an increase in tumor oxygenation by using Mb as an oxygen carrier, we actually observed hemorrhage, decreased oxygenation, and central tumor necrosis. In vitro studies using human endothelial cells demonstrated dramatic changes in cell morphology and increased permeability due to Mb and PEM treatments, which appear to be enhanced in an oxidative environment. These in vitro and in vivo observations are similar to what is seen with tumor vascular disrupting agents.</p><p>For the third aim, I combined radiotherapy (RT) and PEM treatment with a new hypothesis. I originally expected the PEMs to increase tumor oxygenation, thus making the tumor more susceptible to RT. However, considering the results from the second aim, this hypothesis was modified: the PEMs would result in necrosis of the tumor core, while RT would target the more oxygenated rim of the tumor, thus leading to improved tumor growth delay compared with PEM or RT alone. This hypothesis was tested in both orthotopic, syngeneic 4T1 tumors as well as flank FaDu xenografts. 4T1 tumor cells were surgically implanted within the dorsal mammary fat pad of mice and grown until ~200 mm3. A CT microirradiator with a square collimator was used in order to locate and specifically irradiate the tumor. Within 1 h following RT, the PEMs were administered i.v.. Mice receiving PEMs with no RT showed a significant decrease in tumor growth compared with saline-treated mice (p = 0.0001 for time to 3x original tumor volume). In addition, the combination of RT plus PEMs reduced tumor growth compared with RT alone (p = 0.0144 for time to 3x original tumor volume). However, this effect was not seen with FaDu tumors. This may have been due to excessive radiation dose or other compounding factors: the timing between RT and PEM treatment was not optimized, and the number of mice per group was small (3-4). </p><p>Thus, the conclusions for each aim are as follows:</p><p>1. Develop NIR imaging techniques for studying the biodistribution and pharmacokinetics of polymersomes</p><p>NIR imaging techniques were optimized for studying polymersomes, demonstrating long plasma circulation times and accumulation within tumors.</p><p>2. Establish the effects of Mb-containing polymersomes on tumor physiology</p><p>While the hypothesis was that PEMs would accumulate within hypoxic tumors and subsequently increase O2 tension, we observed a rapid decrease in tumor oxygenation followed by a dramatic hemorrhagic effect of Mb polymersomes, which appear to be due to both endothelial cell apoptosis and morphological changes, resulting in central tumor necrosis.</p><p>3. Modify tumor growth through delivery of Mb polymersomes in combination with a cytotoxic therapy specific to aerobic tumors</p><p>Combination therapy of PEMs with RT results in enhanced tumor growth delay in aggressive 4T1 mammary carcinomas compared with RT or PEMs alone.</p><p>These studies have led to a proposed mechanism for the PEM anti-tumor effect in combination with RT. Prior to PEM administration, RT is administered, resulting in tumor cell kill of the well-oxygenated tumor periphery. Mb polymersomes are then injected i.v. and begin to accumulate within tumors due to the EPR effect. As shown in Aim 1, this accumulation occurs over a short time scale. Within 30 min of PEM treatment, the Mb is believed to act on tumor vessels, resulting in morphological changes and apoptosis of endothelial cells. These effects are expected to increase permeability of the vessels and expose the basement membrane, which leads to clotting and decreased blood flow. Both decreased perfusion and increased permeability are believed to have a catastrophic effect on interior tumor vessels. Hemorrhage results as the endothelial cells die, resulting in tumor core necrosis. Therefore, the result is tumor cell kill at the periphery due to RT and central tumor necrosis due to PEM treatment.</p><p>PEMs have potential in cancer therapy as a new class of VDAs. While the mechanism requires further investigation, this work has demonstrated that PEM treatment results in tumor vessel destruction and central necrosis. PEMs accumulate within tumors, thus minimizing the systemic toxicity of treatment commonly seen with VDAs. By combining PEMs with a therapy that kills the better perfused tumor periphery, PEMs show promise in improving tumor response. Future mechanistic studies will be needed in order to maximize vessel damage and optimize combination dosing schedules to improve outcome.</p> / Dissertation
66

Imagerie hyperspectrale par transformée de Fourier : limites de détection caractérisation des images et nouveaux concepts d'imagerie / Hyperspectral imaging by Fourier transfom : detection limits, image characterization, and new imaging concepts

Matallah, Noura 16 March 2011 (has links)
L’imagerie hyperspectrale est maintenant très développée dans les applications de télédétection. Il y a principalement deux manières de construire les imageurs associés : la première méthode utilise un réseau et une fente, et l’image spectrale est acquise ligne par la ligne le long de la trajectoire du porteur. La seconde est basée sur le principe de la spectrométrie par transformée de Fourier (TF). Certains des systèmes utilisés sont construits de manière à enregistrer l’interférogramme de chaque point de la scène suivant le déplacement dans le champ. Le spectre de la lumière venant d’un point de la scène est alors calculé par la transformée de Fourier de son interférogramme. Les imageurs classiques basés sur des réseaux sont plus simples à réaliser et les données qu’ils fournissent sont souvent plus faciles à interpréter. Cependant, les spectro-imageurs par TF fournissent un meilleur rapport signal sur bruit si la source principale de bruit vient du détecteur.Dans la première partie de cette thèse, nous étudions l’influence de différents types de bruit sur les architectures classiques et TF afin d’identifier les conditions dans lesquelles ces dernières présentent un avantage. Nous étudions en particulier l’influence des bruits de détecteur, de photons, des fluctuations de gain et d’offset du détecteur et des propriétés de corrélation spatiale des fluctuations d’intensité du spectre mesuré. Dans la seconde partie, nous présentions la conception, la réalisation et les premiers résultats d’un imageur basé sur un interféromètre de Michelson à dièdres statique nommé DéSIIR (Démonstrateur de Spectro-Imagerie Infrarouge). Les premiers résultats montrent, qu’en mode spectromètre simultané, DéSIIR permet la restitution du spectre avec les spécifications requises dans le cadre des applications recherchées, c'est-à-dire détecter avec une résolution d environ 25 cm-1 un object de quelques degrés plus chaud que le fond de la scène et présentant une signature spectrale entre 3 et 5 juin. En mode spectromètre imageur, après recalage des images, il est possible de reconstruire le spectre de chaque point de la scène observée. / Hyperspectral imaging is now very important in remote sensing applications. There are two main ways to build such imagers : the first one uses a grating and a slit, and the spectral image is acquired line by line along the track of the carrier. The second way is to use the principle of Fourier transform (FT) spectrometry. Some of these systems are built in such a way that they record the interferogram of each point of the scene as it moves through the field of view. The spectrum of the light coming from a particular point is then calculated by the Fourier transform of its interferogram. Classical gratting-based spectral imagers are easier to build and the data they provide a better signal to noise ratio if the main source of noise comes from the detector.In the first part of this thesis, we study the influence of various types of noise on the classic and TF-based architectures to identify the conditions in which these last ones present an advantage. We study particularly the influence of detector noise, photons noise, detector gain and offset fluctuations and spatial correlation properties of the intensity fluctuations. In the second part, we present the conception, the realization and the first results of an imager bases on a Michelson interferometer with dihedrons named DéSIIR (“Démonstrateur de Spectro Imagerie Infrarouge”). The first results show that, in simultaneous spectrometer mode, DéSIIR allows the reconstruction of the spectrum with respect to the specific requirements, which are to be able to detect an objet of some degrees warmer than the background of the scene observed with a resolution of about 25 cm -1. In imager mode, this reconstruction is performed for each point of the scene.
67

Algoritmos de tempo real para melhoramento de imagens capturadas no espectro do infravermelho projetados para síntese em FPGA / Real-time infrared images enhancement algorithms developed for FPGA synthesis

Rotava, Lucas 04 December 2015 (has links)
Este trabalho apresenta o desenvolvimento de algoritmos de processamento de imagens para câmeras térmicas, com o objetivo de sintetizá-los em FPGA. Existem diversas aplicações para imagens térmicas nas áreas médica, de segurança e industrial, por isso o conhecimento e o desenvolvimento de câmeras térmicas são de interesse para a academia e para a indústria. Por consequência, o desenvolvimento de algoritmos que tratem as imagens também representa importante papel. Os algoritmos implementados neste trabalho são: correção de não uniformidade (NUC); substituição de pixels defeituosos, ou bad pixels, (BPR); redução da resolução de cor com realce de contraste; e filtro espacial para realçar detalhes da imagem, chamado de filtro de nitidez. Os três primeiros são algoritmos importantes devido à características dos detectores e de câmeras térmicas, já o filtro de nitidez foi proposto para melhorar a visualização de objetos nas imagens. Com os algoritmos simulados em Matlab foram feitas medidas de contraste e de MTF das imagens de saída, e os resultados obtidos para os algoritmos de realce de contraste e de nitidez mostraram que eles são adições importantes ao conjunto de algoritmos básicos para câmeras térmicas, já que, para alguns casos, o realce de contraste aumentou em mais de 50% a medida de contraste da imagem, em comparação com o algoritmo anterior, e o filtro de nitidez proporcionou valores de MTF até duas vezes maiores. Os algoritmos de NUC e BPR apresentaram os resultados esperados, corrigindo a imagem recebida do detector. As imagens utilizadas eram de 640×512 pixels processadas em uma taxa de 30 fps, e dessa forma optou-se pelo FPGA para a síntese dos algoritmos, sendo possível realizar os processamentos paralelamente contando com a característica de alto throughput inerente a estes componentes. Os algoritmos implementados em FPGA apresentaram desempenho superior aos requisitos mínimos de tempo para o sistema utilizado, sendo perfeitamente capazes de processar o vídeo de entrada em tempo real. / This work presents the development of FPGA-synthesizable image processing algorithms to thermal cameras. There are plenty of applications for thermal imaging in medical, security and industrial areas, therefore, the knowledge and the development of thermal cameras are of great interest to both academia and industry. Consequently, the development of algorithms to enhance the images is also important. The implemented algorithms are: nonuniformity correction (NUC); bad pixel replacement (BPR); pixel depth reduction with contrast enhancement; and emboss spatial filter. The three first algorithms are important because of some characteristics of infrared detectors and cameras, and the emboss filter is proposed to improve the visualization of objects in the images. With the algorithms simulated in Matlab, the contrast and MTF were measured in the output images, and the results showed that the contrast enhancement and the emboss filter algorithms are important additions to the infrared cameras basic set of image processing algorithms since, for some cases, the contrast enhancement was able to improve the contrast by 50% and the emboss filter have doubled the MTF. NUC and BPR algorithms had the expected results, correcting the image from the detector. There were used images with resolution of 640×512 at 30 frames per second and, because of this, it was chosen to synthesize the algorithms in an FPGA, this way it is possible to run them in parallel, counting on the high throughput characteristic of the FPGAs. The implemented algorithms have better timing performance than the needed for the system used, being perfectly able to process the input video in real time.
68

Algoritmos de tempo real para melhoramento de imagens capturadas no espectro do infravermelho projetados para síntese em FPGA / Real-time infrared images enhancement algorithms developed for FPGA synthesis

Lucas Rotava 04 December 2015 (has links)
Este trabalho apresenta o desenvolvimento de algoritmos de processamento de imagens para câmeras térmicas, com o objetivo de sintetizá-los em FPGA. Existem diversas aplicações para imagens térmicas nas áreas médica, de segurança e industrial, por isso o conhecimento e o desenvolvimento de câmeras térmicas são de interesse para a academia e para a indústria. Por consequência, o desenvolvimento de algoritmos que tratem as imagens também representa importante papel. Os algoritmos implementados neste trabalho são: correção de não uniformidade (NUC); substituição de pixels defeituosos, ou bad pixels, (BPR); redução da resolução de cor com realce de contraste; e filtro espacial para realçar detalhes da imagem, chamado de filtro de nitidez. Os três primeiros são algoritmos importantes devido à características dos detectores e de câmeras térmicas, já o filtro de nitidez foi proposto para melhorar a visualização de objetos nas imagens. Com os algoritmos simulados em Matlab foram feitas medidas de contraste e de MTF das imagens de saída, e os resultados obtidos para os algoritmos de realce de contraste e de nitidez mostraram que eles são adições importantes ao conjunto de algoritmos básicos para câmeras térmicas, já que, para alguns casos, o realce de contraste aumentou em mais de 50% a medida de contraste da imagem, em comparação com o algoritmo anterior, e o filtro de nitidez proporcionou valores de MTF até duas vezes maiores. Os algoritmos de NUC e BPR apresentaram os resultados esperados, corrigindo a imagem recebida do detector. As imagens utilizadas eram de 640×512 pixels processadas em uma taxa de 30 fps, e dessa forma optou-se pelo FPGA para a síntese dos algoritmos, sendo possível realizar os processamentos paralelamente contando com a característica de alto throughput inerente a estes componentes. Os algoritmos implementados em FPGA apresentaram desempenho superior aos requisitos mínimos de tempo para o sistema utilizado, sendo perfeitamente capazes de processar o vídeo de entrada em tempo real. / This work presents the development of FPGA-synthesizable image processing algorithms to thermal cameras. There are plenty of applications for thermal imaging in medical, security and industrial areas, therefore, the knowledge and the development of thermal cameras are of great interest to both academia and industry. Consequently, the development of algorithms to enhance the images is also important. The implemented algorithms are: nonuniformity correction (NUC); bad pixel replacement (BPR); pixel depth reduction with contrast enhancement; and emboss spatial filter. The three first algorithms are important because of some characteristics of infrared detectors and cameras, and the emboss filter is proposed to improve the visualization of objects in the images. With the algorithms simulated in Matlab, the contrast and MTF were measured in the output images, and the results showed that the contrast enhancement and the emboss filter algorithms are important additions to the infrared cameras basic set of image processing algorithms since, for some cases, the contrast enhancement was able to improve the contrast by 50% and the emboss filter have doubled the MTF. NUC and BPR algorithms had the expected results, correcting the image from the detector. There were used images with resolution of 640×512 at 30 frames per second and, because of this, it was chosen to synthesize the algorithms in an FPGA, this way it is possible to run them in parallel, counting on the high throughput characteristic of the FPGAs. The implemented algorithms have better timing performance than the needed for the system used, being perfectly able to process the input video in real time.
69

Imageurs à amplification / Amplified imagers

Gach, Jean-Luc 03 April 2018 (has links)
La quête du détecteur parfait, sans bruit, capable de détecter des photons uniques dans le visible et l’infrarouge, et ultimement de déterminer leur énergie est le graal de la détection. Pour arriver à ce but, de nombreux scientifiques ont développé des dispositifs depuis plusieurs dizaines d’années, et les astronomes ont toujours été à la pointe en ce domaine. En ce sens les imageurs à amplification semblent être la voie la plus rapide et la plus prometteuse pour atteindre ce but ultime. Ainsi après un bref historique de l’état de l’art sont exposés les systèmes à comptage de photons (IPCS) développés au LAM, qui ont été utilisés sur les télescopes ESO 3m60, OHP 1m93 ou encore WHT 4m20. Sont ensuite abordés les dispositifs imageurs intégrés à amplification comme les EMCCD (Electron multiplying charge coupled devices) dans le visible, avec quelques exemples de leur utilisation en astronomie. C’est la technologie qui, appliquée aux senseurs de front d’onde, aura permis conjointement à d’autres développements l’avènement des optiques adaptatives extrêmes comme celle de l’instrument VLT-SPHERE ou encore de SUBARU-SCExAO. Pour finir les e-APD (electron initiated avalanche photodiode) dans l’infrarouge seront abordés. Les e-APD ont cette propriété très intéressante d’être des amplificateurs quasi parfaits, et ont une capacité à détecter l’énergie des photons, des propriétés qui seront développées et analysées. Nous finirons par les perspectives et les progrès que nous sommes en droit d’attendre dans les prochaines années. / The quest for the perfect, noiseless detector, capable of detecting unique photons in the visible and infrared, and ultimately determining their energy is the grail of detection. To achieve this goal, many scientists have developed devices for several decades, and astronomers have always been at the forefront in this area. In this sense amplification imagers seem to be the fastest and most promising way to achieve this ultimate goal. Thus, after a brief history of the state of the art are exposed the photon counting systems (IPCS) developed at LAM, which were used on ESO telescopes 3m60, OHP 1m93 or WHT 4m20. Imaging integrated imaging devices such as Electron Multiplying Charge Coupled Devices (EMCCDs) are then discussed in the visible, with some examples of their use in astronomy. It is the technology that, applied to the wavefront sensors, has jointly enabled other developments the advent of extreme adaptive optics such as the VLT-SPHERE or SUBARU-SCExAO. To finish the e-APD (electron-induced avalanche photodiode) in the infrared will be discussed. E-APDs have this very interesting property of being almost perfect amplifiers, and have an ability to detect photon energy, properties that will be developed and analyzed. We will end up with the prospects and the progress that we are entitled to expect in the coming years.
70

Infrared Optical Imaging Techniques for Gas Visualization and Measurement

Safitri, Anisa 2011 May 1900 (has links)
Advancement in infrared imaging technology has allowed the thermal imaging to detect and visualize several gases, mostly hydrocarbon gases. In addition, infrared cameras could potentially be used as a non-contact temperature measurement for gas and vapor. However, current application of infrared imaging techniques for gas measurements are still limited due to several uncertainties in their performance parameters. The aim of this research work was to determine the key factors in the application of infrared imaging technology for gas visualization and a non-contact temperature measurement. Furthermore, the concentration profile and emission rate of the gas are predicted by combining the application of the infrared imaging method with gas dispersion modeling. In this research, infrared cameras have been used to visualize liquefied natural gas (LNG) plumes from LNG spills on water. The analyses of the thermograms showed that the apparent temperatures were different from the thermocouple measurement which occurred due to the assumption of that the object emissivity was always equal to unity. The emissivity for pure methane gas and a mixture of methane and atmospheric gases were then evaluated in order to obtain the actual temperature distribution of the gas cloud. The results showed that by including the emissivity value of the gas, the temperature profile of the dispersed gas obtained from a thermal imaging measurement was in good agreement with the measurement using the thermocouples. Furthermore, the temperature distribution of the gas was compared to the concentration of a dispersed LNG vapor cloud to obtain a correlation between the temperature and the concentration of the cloud. Other application of infrared imaging technique was also conducted for leak detection of natural gas from a pipeline. The capability of an infrared camera to detect a fugitive gas leak was combined with the simulation of vapor discharge and dispersion in order to obtain a correlation between the emission rates and the sizes of the gas plume to the minimum detectable concentration. The relationship of the methane gas cloud size to the gas emission rate was highly dependent to the prevailing atmospheric condition. The results showed that the correlation were best to predict the emission rate less than 0.2 kg/s. At higher emission rate, the increase in gas release rate did not change the size of the cloud significantly.

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