Dissertations / Theses on the topic 'Radiance'
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Rowlett, Coleman. "Spectral Radiance." Digital Commons @ Butler University, 2018. https://digitalcommons.butler.edu/grtheses/500.
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Spectral Radiance is a concerto for alto saxophone and chamber orchestra. In this paper, the influence of Franz Schreker's Kammersymphonie on Rowlett's compositional inspiration is discussed in detail. In addition, the various compositional elements that make up the work are explained. These include elements of form, motivic development, sharing themes between movements, and harmony. Rowlett's use of these compositional elements aims to create cohesion throughout the work as a whole. The paper acts as a guide, retracing the steps taken by the composer during the composition of the concerto.
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Franke, Tobias Alexander. "The delta radiance field." Phd thesis, Technische Universität Darmstadt, 2015. http://tuprints.ulb.tu-darmstadt.de/4992/1/phd_thesis.pdf.
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The wide availability of mobile devices capable of computing high fidelity graphics in real-time has sparked a renewed interest in the development and research of Augmented Reality applications. Within the large spectrum of mixed real and virtual elements one specific area is dedicated to produce realistic augmentations with the aim of presenting virtual copies of real existing objects or soon to be produced products. Surprisingly though, the current state of this area leaves much to be desired: Augmenting objects in current systems are often presented without any reconstructed lighting whatsoever and therefore transfer an impression of being glued over a camera image rather than augmenting reality. In light of the advances in the movie industry, which has handled cases of mixed realities from one extreme end to another, it is a legitimate question to ask why such advances did not fully reflect onto Augmented Reality simulations as well.
Generally understood to be real-time applications which reconstruct the spatial relation of real world elements and virtual objects, Augmented Reality has to deal with several uncertainties. Among them, unknown illumination and real scene conditions are the most important. Any kind of reconstruction of real world properties in an ad-hoc manner must likewise be incorporated into an algorithm responsible for shading virtual objects and transferring virtual light to real surfaces in an ad-hoc fashion. The immersiveness of an Augmented Reality simulation is, next to its realism and accuracy, primarily dependent on its responsiveness. Any computation affecting the final image must be computed in real-time. This condition rules out many of the methods used for movie production.
The remaining real-time options face three problems: The shading of virtual surfaces under real natural illumination, the relighting of real surfaces according to the change in illumination due to the introduction of a new object into a scene, and the believable global interaction of real and virtual light. This dissertation presents contributions to answer the problems at hand.
Current state-of-the-art methods build on Differential Rendering techniques to fuse global illumination algorithms into AR environments. This simple approach has a computationally costly downside, which limits the options for believable light transfer even further. This dissertation explores new shading and relighting algorithms built on a mathematical foundation replacing Differential Rendering. The result not only presents a more efficient competitor to the current state-of-the-art in global illumination relighting, but also advances the field with the ability to simulate effects which have not been demonstrated by contemporary publications until now.
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Tarigan, Jos Timanta. "Pre-computed surface radiance transfer." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93078.
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Rendering a complex global illumination scene requires an extensive computational resource. It is hard to achieve a real time rendering of a complex object using explicit 3D information. To tackle this obstacle, many techniques have been introduced to close the gap between complex 3D scene and real time rendering. One of the proposed solutions is using an image-based rendering technique. Image-based rendering is a method to achieve the desired image by referencing the sampled image as a source. This thesis will focus on a mix between image-based rendering and geometrybased rendering. Instead of rendering directly using a global illumination method, we use a set of image, which are captured during the offline rendering. We call the firstprocess as light transport pre-calculation process. These images then treated as a texture and will be attached to the polygon during the online rendering process. Based on the viewer position, the system decides which value to attach on the polygon. This rendering process however requires a lot of calculation. Luckily, recent graphic card allows developer to exploit GPU‟s hardware by making it possible to reprogram the rendering pipeline. As a graphic dedicated hardware, GPU has a lot of advantage to do a rendering compared to CPU. For example its nature of parallel processing is an advantage considering most of rendering process is a parallel processing. Other than splitting the computational task, we also would like to see how we can use the availability of memory. This can be done by processing the scene before the rendering process took place. This thesis will discuss and implement how to split the burden of processing power by rendering a pre-calculated data for later render. Since the pre-rendered data could be huge, it is also important to discuss a compression method that can be applied in GPU architecture and fast enough to be rendered as a real time. Keywords: Pre-computed Surface Radiance Transfer, Global Illumination, BRDF, Image Based Modeling and Rendering, Real Time Rendering, GPU Programming, GLSL.
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McKenzie, Chapter Harrison Lee. "Textured Hierarchical Precomputed Radiance Transfer." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/333.
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Computing complex lighting simulations such as global illumination is a computationally intensive task. Various real time solutions exist to approximate aspects of global illumination such as shadows, however, few of these methods offer single pass rendering solutions for soft shadows (self and other) and inter-reflections. In contrast, Precomputed Radiance Transfer (PRT) is a real-time computer graphics technique which pre-calculates an object's response to potential incident light. At run time, the actual incident light can be used to quickly illuminate the surface, rendering effects such as soft self-shadows and inter-reflections. In this thesis, we show that by calculating PRT lighting coefficients densely over a surface as texture data, additional surface detail can be encoded by integrating other computer graphics techniques, such as normal mapping. By calculating transfer coefficients densely over the surface of a mesh as texture data, greater fidelity can be achieved in lighting coarse meshes than simple interpolation can achieve. Furthermore, the lighting on low polygon objects can be enhanced by drawing surface normal and occlusion data from highly tessellated, detailed meshes. By applying such data to a decimated, simplified mesh, a more detailed and visually pleasing reconstruction can be displayed for a lower cost. In addition, this thesis introduces Hierarchical PRT, which extends some surface effects, such as soft shadows, between objects. Previous approaches to PRT used a more complex neighborhood transfer scheme in order to extend these lighting effects. Hierarchical PRT attempts to capture scene information in a tree data structure which represents coarse lighting relationships between objects. Potential occlusions can be found at run time by utilizing the same spherical harmonic representation used to represent surface lighting to instead store light "filters" between scene tree nodes. Such "filters" can be combined over a set of nodes in the scene to obtain the net shadowing of an object with good performance.
We present both visually pleasing results on simplified meshes using normal mapping and textured PRT and initial results using Hierarchical PRT that captures low frequency lighting information for a small number of dynamic objects which shadow static scene objects with good results.
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Buerli, Michael. "Radiance Caching with Environment Maps." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/991.
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The growing demand for realistic renderings in both film and games has led to a number of proposed solutions to the Global Illumination problem. In order to imitate natural lighting, it is necessary to gather indirect illumination of the surrounding environment for lighting computations. This is a computationally expensive problem, requiring the sampling or rasterization of the hemisphere surrounding each ray intersection, to which there is no standardized solution.
In this thesis we propose a new method of approximation using environment maps for caching radiance. The proposed method leverages a voxelized scene representation for storing direct illumination and a cache of environment maps for integrating indirect illumination. By using a voxelized scene to gather indirect lighting contributions and caching these contributions spatially, we are able to achieve fast and convincing renders of large complex scenes.
The result of our implementation produces images comparable to those of existing Monte Carlo integration methods with render speeds a magnitude or more faster.
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Koks, Don. "Decoherence, entropy and thermal radiance using influence functionals /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phk798.pdf.
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Wang, Zhen. "Modeling wildland fire radiance in synthetic remote sensing scenes /." Online version of thesis, 2007. http://hdl.handle.net/1850/5787.
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Marshall, Samuel I. "Modtran radiance modeling of multi-angle worldview-2 imagery." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37669.
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Approved for public release; distribution is unlimitedThe WorldView-2 satellite, launched in 2010 by DigitalGlobe, provides researchers with the ability to collect high resolution, multi-angle, 8-band multispectral imagery. This offers a unique opportunity to investigate the reflectance propertiesincluding the bidirectional reflectance distribution functionof surfaces detected from a space-based remote sensing platform. Eight images were collected over Rio de Janeiro on January 19, 2010, at approximately 1000 local time. Solar geometry during the collect remained constant while sensor geometry ranged from approximately 10 degrees off-nadir to 60 degrees off-nadir, fore and aft. To enhance understanding and provide comparison data with the multi-angle imagery data, radiance models were generated using the Moderate Resolution Atmospheric Transfer code. General models, using surface albedos ranging from 1% to 100%, and comparison models, using properties as close as possible to that found in the imagery, were built. Using data derived from all sources, variations were readily apparent that could be attributed to the multi-angle geometry of the collect, the wavelength of the light sensed and reflectance
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Bala, Kavita. "Radiance interpolants for interactive scene editing and ray tracing." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80201.
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Křivánek, Jaroslav. "Radiance caching for global illumination computation on glossy surfaces." Rennes 1, 2005. http://www.theses.fr/2005REN1S116.
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L'illumination globale est un moyen permettant de produire des images de synthèse dites photoréalistes. Elle joue un rôle encore plus important dans le cas de scènes contenant des objets en parties spéculaires, c'est à dire non parfaitement lisses. Cette thèse traite principalement du problème du calcul de l'illumination globale dans le cas de ce type de scène où les objets sont caractérisés par des réflectances de basse fréquence. Nous proposons une méthode utilisant un cache de luminance, méthode basée sur le lancer de rayon et prenant en compte les surfaces spéculaires non parfaitement lisses (ayant une rugosité microscopique) dont les réflectances possèdent des caractéristiques de basse fréquence. L'algorithme proposé exploite la variation douce de l'éclairage sur une surface en interpolant l'éclairage indirect à partir de données éparses stockées dans le cache. Notre méthode permet de générer des images de grande qualité en un temps plus court que celui obtenu avec les méthodes existantes.
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Krivanek, Jaroslav Bouatouch Kadi Zara Jiri. "Radiance caching for global illumination computation on glossy surfaces." [S.l.] : [s.n.], 2005. ftp://ftp.irisa.fr/techreports/theses/2005/krivanek.pdf.
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Thèse doctorat : Informatique : Rennes 1 : 2005. Thèse doctorat : Computer science and engineering : Czech technical university (Prague) : 2005.Thèse soutenue en co-tutelle. Thèse en anglais avec un résumé en français. Le titre de la couv. est en français. Bibliogr. p. 103-114.
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David, Pierre-Gérard. "Amplification laser et diagnostic temporel de paquets d'électrons ultra-relativistes en interaction laser-plasma." Paris 11, 2004. http://www.theses.fr/2004PA112286.
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La thèse dont ce manuscrit fait l’objet traite de deux des possibles applications de l’interaction d’un laser intense avec la matière. La première de ces applications est l’utilisation d’un plasma pour catapulter des particules à des énergies relativistes. Un plasma peut en effet supporter des champs électriques cent, voir mille fois supérieurs à ceux dans les matériaux classiques. Les lasers de puissance permettent d’exploiter cette capacité en engendrant d’importants champs électriques de sillage afin d’accélérer des électrons. Dans le présent manuscrit est étudié en particulier la mise ne place d’un nouveau diagnostic de mesure de durée pour les faisceaux d’électrons obtenus. Le diagnostic est basé sur une technique électro-optique et possède une excellente résolution. Son étude, sa mise en place, ses tests et ses premiers résultats sont présentés. La seconde application que couvre ce manuscrit est l’utilisation d’un plasma comme amplificateur laser, en régime dit de super-radiance. En effet, un amplificateur laser est un élément capable de transférer de l’énergie d’une source extérieure vers l’impulsion laser qui le traverse. Or un plasma, par le biais des ondes qu’il véhicule, est capable de réaliser ce transfert, tout en supportant des intensités bien supérieures aux techniques d’amplification traditionnelles. Si ce domaine d’étude est encore récent, sa maîtrise constitue pourtant un des développements clé qui pourrait conduire la technologie laser vers des seuils d’intensité encore jamais atteintThe present thesis relates of two specific applications of the laser-matter interaction scheme. The first of those applications is using a plasma as a relativistic particles accelerator. A plasma can actually support electric fields far beyond what classical materials are capable of. High intensity lasers can be used to generate large electric wake fields in order to accelerate electrons. The thesis discuss of such experiments and in particular of the integration of a new diagnostic to mesure the duration of the produced electron beams. The diagnostic is based on an electro-optic technic and has a very good resolution. Study, setup and first results are presented. The second application covered is the use of a plasma as a laser amplificator, in the so-called regime of super-radiance. Actually, a plasma is capable of transfering large amounts of energy from a laser beam to another via the waves it carries. Developping such a technic could be usefull to achieve laser intensities far beyond the actual limits. This field of study is only at its beginings, but some first results are presented
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Wright, David Thomas. "Measurements and modelling of hyperspectral radiance transfer in coastal waters." Thesis, University of Strathclyde, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443128.
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Tuell, Grady H. "A multichannel restoration approach to radiance refinement in imaging spectroscopy /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486402544591707.
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Fornaro, Marie. "Touched with All the Radiance that a Sudden Sun Discloses." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5929.
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The thread running through my work is a constant impulse to rend and repair; to make, unmake, and remake. This repetitive and circular approach allows me to confront the cyclical nature of gendered oppression. What does it mean to make something beautiful and then to dismantle it? How do we reckon with the pieces that remain? By deconstructing the beautiful and lovingly crafted objects that I spend hours making, I recenter “craft” as a verb rather than a noun, forcing myself and my audience to resist the comforting illusion of certainty.
I contextualize my piecework and quilting in a long line of American women who have wielded needle and thread to speak truth to power. Informed by intersectional feminist studies and grounded in the historical tragedy of the witch hunts of the Middle Ages, my research plumbs the confluence of quiltmaking and language, both encoded and overt. I believe that textile crafts, as the media least reified by the fine art establishment, hold a potent ability to confront the capitalist, sexist, and colonialist assumptions propping up the false dichotomy between mind and body, between art and craft, between those who are permitted to speak and those who are silenced.
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Oliveira, de Araujo Michelle. "Super- et sous-radiance dans un nuage dilué d'atomes froids." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4200/document.
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Le problème de l'interaction de N atomes avec un faisceau laser et les modes du vide peut donner lieu à de nombreux phénomènes intéressants concernant l’émission spontanée de la lumière et sa propagation dans l’échantillon. Les effets coopératifs, par exemple, tels que la super- et la sous-radiance, sont des effets liés à la cohérence créée entre les atomes lorsqu'un photon est émis spontanément par un seul atome excité. La super-radiance peut être définie comme le renforcement de l'émission spontanée due à une interférence constructive de la lumière diffusée. Son homologue, la sous-radiance, est le piégeage d'une partie de la lumière restante en raison d'interférences destructives. Dans les atomes froids, certains travaux théoriques antérieurs prédisent et caractérisent ces deux effets coopératifs dans un nuage atomique large et diluée, dans le régime des faibles intensités et à grands désaccords du laser incident. Le modèle théorique est un modèle de dipôles couplés pour atomes à deux niveaux pilotés par un champ de faible intensité et dans l'approche scalaire. L'expérience consiste à mesurer les taux de d’décroissance super- et sous-radiants à partir de l’intensité temporelle émise après la coupure du laser incident en régime stationnaire. Notre schéma expérimental consiste en un piège magneto-optique d’atomes de rubidium 87 à grandes épaisseurs optiques à résonance. Un faisceau sonde excite les atomes proches de la raie D2. L’intensité émise est détectée par un détecteur de photons uniques dépourvu d’afterpulsing et une procédure d’étalonnage nous permet de déterminer l’épaisseur optique résonante du nuage et sa température. Dans ce travail, nous rapportons l’observation expérimentale de la super- et sous-radiance dans un grand nuage d’atomes froids. Pour la sous-radiance, le résultat principal est l’évolution linéaire du temps caractéristique avec l’épaisseur optique résonante du nuage et son indépendance du désaccord. Pour la super-radiance, on observe la super-radiance en dehors de la direction vers l’avant. Nous vérifions la validité de nos interprétations avec les prédictions du modèle de dipôles couplés. Finalement, nous discutons l’interaction entre la sous-radiance et le piégeage de radiation, ainsi que des prévisions théoriques concernant : la configuration d’un nuage phasé, pour contrôler l’émission de l’amplitude sousradiante ; et les effets de température, où la sous-radiance s’avère robuste dans une large gamme de températuresThe problem of the interaction of N atoms with a laser beam and vacuum modes can give rise to many interesting phenomena concerning the spontaneous emission of light and its propagation in the medium. The cooperative effects, for example, such as superadiance and subradiance, are effects related to the coherence created between the atoms when a photon is emitted spontaneously by a single excited atom. Superradiance can be defined as the enhancement of the spontaneous emission due to constructive interference of the scattered light. Its counterpart, subradiance, is the trapping of some remaining light due to destructive interference. In cold atoms, some previous theoretical works predict and characterize these two cooperative effects in a large and diluted atomic cloud, in the regime of low intensities and large detunings of the incident laser. The theoretical model is a coupled-dipole model for two-level atoms driven by a low-intensity field and in the scalar approach. The experiment consists in measuring the super- and subradiant decay rates from the temporal emitted intensity after the switch off of the incident laser in the steady state. Our experimental setup consists in a magneto-optical trap of rubidium 87 atoms at large resonant optical thicknesses. A probe beam excites the atoms close to the D2 line. The intensity emitted is detected by a single photon detector with no afterpulsing and a calibration procedure allows us to determine the resonant optical thickness of the cloud and its temperature. In this work, we report the experimental observation of super- and subradiance in a large cloud of cold atoms. For subradiance, the main result is the linear evolution of the characteristic time with the resonant optical thickness of the cloud and its independence of the detuning. For superradiance, we observe superradiance out of the forward direction. We verify the validity of our interpretations with the predictions of the coupled-dipole model. Finally, we discuss the interplay of subradiance and radiation trapping, as well as theoretical predictions for: a setup of a phased cloud, to control the subradiant amplitude emission; and temperature effects, where subradiance is shown to be robust in a large range of temperatures
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Fay, Matthew Edward. "An analysis of hyperspectral imagery data collected during Operation Desert Radiance." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA302643.
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Thesis (M.S. in Systems Technology (Space Systems Operations)) Naval Postgraduate School, June 1995."June 1995." Thesis advisor(s): Richard Christopher Olsen. Bibliography: p. 99-101. Also available online.
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Xiang, Xuwu. "The delta-Sobolev approach for modeling solar spectral irradiance and radiance." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25801.
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Wood, David S. "Thermistor validation and path radiance effects in ship thermal image measurements." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28607.
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Grippa, Manuela. "Retrieval of tropospheric temperature and composition profiles from infrared radiance measurements." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/527.
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Fox, Cathryn. "Far-infrared spectral radiance studies : application to water vapour and cirrus." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/25752.
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This thesis presents the analysis of high-resolution spectral radiances recorded using the Imperial College Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) instrument, which uniquely has the ability to record high resolution in-situ measurements, both up-welling and down-welling, in the far-infrared spectral region 80-800cm-1. The TAFTS data used in this work has been recorded during two diverse field campaigns, one ground-based, and one onboard the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft. The far-infrared spectral region has been shown to have a dominant contribution to the radiative cooling of the planet to space. Atmospheric water vapour is known to absorb radiation in a pure rotation band in the far-infrared, and also exhibits a background slowly-varying absorption known as the water vapour continuum. Observations of far-infrared radiances made by TAFTS during the Radiative Heating in Underexplored Bands Campaign (RHUBC) in Barrow, Alaska, are compared to simulations using line-by-line radiative transfer models in order to validate the current water vapour continuum parameterisation. Results presented here show that the current MT-CKD v2.5 parameterisation is accurately representing the water vapour continuum at wavenumbers between 350-500 cm-1. This thesis also considers the radiative effect of cirrus clouds in the far-infrared. These clouds have an important influence on current climate, and are known to scatter and absorb radiation in the infrared, however currently there have been relatively few measurements of the cirrus radiative effect in the far-infrared spectral region. Presented here are mid- and far-infrared observations of the radiative signature of cirrus recorded using the TAFTS and the UK Met Office Airborne Research Interferometer Evaluation System (ARIES) instruments, during the first phase of the aircraft-based Cirrus Coupled Cloud-Radiation Experiment (CIRCCREX), which flew out of Prestwick, Scotland in November 2013. These spectral measurements were compared to simulations using the LBLDIS model, which utilises cirrus scattering databases developed by Baum et al. at the SSEC, University of Wisconsin-Madison. This work represents the first time that the consistency of these databases have been tested across the entire infrared region. It was found that the model was underestimating brightness temperatures in the region 330-600 cm-1, and that further work is required in this region.
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Merzouk, Slimane. "Architecture logicielle et algorithmes pour la résolution de l'équation de radiance." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL068N.
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Les méthodes utilisées pour résoudre l'équation de radiance sont fondées aujourd'hui sur des approximations qui permettent de rendre le problème calculable. Dans les approches développées à ce jour, on distingue les méthodes d'échantillonnage et les méthodes variationnelles. Notre travail se situe dans le cadre de cette dernière approche, et apporte des contributions à deux niveaux : au niveau théorique. Dans les solutions actuelles, les hypothèses physiques sont actuellement restrictives au niveau de la composition spectrale de la lumière. Pour remédier à ce problème nous proposons un algorithme permettant de traiter des distributions continues et discontinues. Au niveau pratique nous croyons qu'une meilleure connaissance des problèmes liés à l'implantation des algorithmes qui concourent à la résolution de l'équation de radiance est utile. Nous avons pour cela construit une architecture logicielle permettant d'implanter les algorithmes et les structures de données nécessaires à cette résolution. L’originalité de la conception de cette architecture, que nous avons souhaité la plus flexible et évolutive possible constitue une contribution majeure de cette thèse. Nous montrons en particulier comment des solutions intégrant des fonctions physiques plus complexes (general reflectance function), des options différentes (discontinuity meshing, importance error-driven), ou des techniques de calcul par raffinement plus élaborées (clustering) peuvent être intégrées à notre architecture, en réutilisant une grande partie du code, et en conservant une bonne stabilité et de bonnes performances.
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Jackson, Jeremy D. "Layered Deformotion with Radiance: A Model for Appearance, Segmentation, Registration, and Tracking." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-07092007-104249/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Vela, Patricio, Committee Member ; Tannenbaum, Allen, Committee Member ; Yezzi, Anthony, Committee Chair ; Turk, Greg, Committee Member ; Lanterman, Aaron, Committee Member.
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Miller, Brian Herbert. "Improved aerosol optical depth and particle size index from satellite detected radiance." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26590.
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Vanhoey, Kenneth. "Traitement conjoint de la géométrie et de la radiance d'objets 3D numérisés." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAD005/document.
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Depuis quelques décennies, les communautés d'informatique graphique et de vision ont contribué à l'émergence de technologies permettant la numérisation d'objets 3D. Une demande grandissante pour ces technologies vient des acteurs de la culture, notamment pour l'archivage, l'étude à distance et la restauration d'objets du patrimoine culturel : statuettes, grottes et bâtiments par exemple. En plus de la géométrie, il peut être intéressant de numériser la photométrie avec plus ou moins de détail : simple texture (2D), champ de lumière (4D), SV-BRDF (6D), etc. Nous formulons des solutions concrètes pour la création et le traitement de champs de lumière surfaciques représentés par des fonctions de radiance attachés à la surface.Nous traitons le problème de la phase de construction de ces fonctions à partir de plusieurs prises de vue de l'objet dans des conditions sur site : échantillonnage non structuré voire peu dense et bruité. Un procédé permettant une reconstruction robuste générant un champ de lumière surfacique variant de prévisible et sans artefacts à excellente, notamment en fonction des conditions d'échantillonnage, est proposé. Ensuite, nous suggérons un algorithme de simplification permettant de réduire la complexité mémoire et calculatoire de ces modèles parfois lourds. Pour cela, nous introduisons une métrique qui mesure conjointement la dégradation de la géométrie et de la radiance. Finalement, un algorithme d'interpolation de fonctions de radiance est proposé afin de servir une visualisation lisse et naturelle, peu sensible à la densité spatiale des fonctions. Cette visualisation est particulièrement bénéfique lorsque le modèle est simplifiéVision and computer graphics communities have built methods for digitizing, processing and rendering 3D objects. There is an increasing demand coming from cultural communities for these technologies, especially for archiving, remote studying and restoring cultural artefacts like statues, buildings or caves. Besides digitizing geometry, there can be a demand for recovering the photometry with more or less complexity : simple textures (2D), light fields (4D), SV-BRDF (6D), etc. In this thesis, we present steady solutions for constructing and treating surface light fields represented by hemispherical radiance functions attached to the surface in real-world on-site conditions. First, we tackle the algorithmic reconstruction-phase of defining these functions based on photographic acquisitions from several viewpoints in real-world "on-site" conditions. That is, the photographic sampling may be unstructured and very sparse or noisy. We propose a process for deducing functions in a manner that is robust and generates a surface light field that may vary from "expected" and artefact-less to high quality, depending on the uncontrolled conditions. Secondly, a mesh simplification algorithm is guided by a new metric that measures quality loss both in terms of geometry and radiance. Finally, we propose a GPU-compatible radiance interpolation algorithm that allows for coherent radiance interpolation over the mesh. This generates a smooth visualisation of the surface light field, even for poorly tessellated meshes. This is particularly suited for very simplified models
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Nestler, Scott T. "Statistical analysis of atmosphere properties for estimation of infrared radiance of ballistic missiles." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA366780.
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Doménech, García Carlos. "Theoretical Approach to the Radiance-to-Flux Conversion in the EarthCARE Mission Framework." Doctoral thesis, Universitat de València, 2008. http://hdl.handle.net/10803/10342.
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The research of the Thesis, "Theoretical Approach to the Radiance-to-Flux Conversion in the EarthCARE Framework", is aimed at studying the instantaneous TOA radiance-to-flux conversion for the prospective Broad-Band Radiometer (BBR) on-board the EarthCARE (Earth Clouds Aerosols and Radiation Explorer) platform, through the development of theoretical angular distribution models based on the specific designing features of the instrument. The inversion procedure has been undertaken to obtain the apparent TOA fluxes according to the flux retrieval accuracy required for the mission. The ADMs employed in previous missions make use of a single radiance in the inversion process. With the specific BBR along-track configuration, three simultaneous radiances point the same target, thus providing more information on the anisotropy of the observed scene. This additional information is employed to construct more accurate inversion schemes than those using a single radiance, thus the objective has been to construct theoretical ADMs based on the specific characteristics designed for this pioneering instrument. However, the resulting angular models are not a finished product to be directly applied over EarthCARE data. This is an attempt to study one potential solution and assess its drawbacks and advantages.Considering that the use of existing ADMs have important shortcomings, the Thesis opens an unexplored study line by which detailed numerical calculations are used to assess and construct ADMs. A specific module of the EarthCARE Simulator has been employed to carry out the broad-band radiative transfer computations, namely the semi-analytical Monte-Carlo radiative transfer code. In spite of the difficulty associated with addressing the unlimited atmospheric conditions needed in order to determine ADMs based on model calculations, a theoretical database has been constructed considering different surface, atmospheric and cloud conditions. The variations on these parameters are conditioned to the EarthCARE satellite orbit and physical ligatures. At the end, more than 8x104 detailed scenes has been produced, building up significant ensembles with a robust statistical analysis, and including realistic 3-D cloud effects. A high number of calculations has been performed on the Computing Centre from the University of Valencia while the European Space Agency (ESA) facilitated a significant computing resource by allowing us to implement the EarthCARE Simulator on the ESA Earth Observation Grid Processing-on-Demand (EO G-POD). Three different inversion methodologies have been specifically developed to take advantage of the along-track scanner configuration of the EarthCARE BBR. Flux can be estimated, as a result of the study, by using an optimized classical inversion procedure with different effective radiance definitions, namely along-track and average methods, or defining the flux as the linear combination of the three-view radiances. These conversion methodologies has been applied to a BBR-like CERES representative dataset, and the results has been compared to the flux estimates obtained by the single-view based CERES ADMs. It has been shown that the application of theoretical ADMs on satellite-measured radiances is far from straightforward. The current approach is presently far from complete and requires significant further research. Empirical ADMs must farther studied before they are rule out.A number of multi-layer bins have been generated for a prototype BBR ADM scene definition, still experimental though. Twenty five multi-layered realistic cloud scenes have been built for this study employing a 3-D stochastic cloud model generator. Since the cloud-imager retrievals are insufficient for the BBR scene identification (ID) in multi-layer cloud, the radiance-to-flux conversion provides large errors. The use of the active instruments helps to determine the type of clouds involved in the scene in most multi-layer situations. The Thesis demonstrates the potential improvement of the radiance-to-flux conversion, by adequately selecting the ADM scene definition and including information from active instruments on-board EarthCARE platform in the scene ID.La Tesis, "Theoretical Approach to the Radiance-to-Flux Conversion in the EarthCARE Mission Framework", responde a uno de los principales intereses de la misión espacial EarthCARE (Earth Clouds Aerosols and Radiation Explorer), el estudio de procedimientos para la estimación flujos a partir de las radiancias del radiómetro de banda ancha Broad-Band Radiometer (BBR) a bordo de la misión. Los objetivos se centran, por tanto, en establecer la metodología para la conversión instantánea de radiancias en techo de la atmósfera a densidades de flujo radiante. Ésta, basada en el desarrollo teórico de modelos de dependencia angular (ADM), se define teniendo en cuenta las características específicas del instrumento. Se optimiza aprovechando que las tres visiones del BBR aportan información angular adicional, lo que posibilita una mejora en la precisión obtenida por los algoritmos de conversión respecto a la que se obtiene con modelos angulares que emplean una única radiancia. El proceso ha sido desarrollado considerando el error máximo atribuible a la obtención de flujos estipulado en los requisitos de precisión de la misión. De tal modo que los flujos aparentes determinados a partir de la conversión de radiancias satisfacen, en su gran mayoría, este requisito. La aspiración de este trabajo no es dar una respuesta definitiva a la estimación de flujos para EarthCARE, si no estudiar una de las posibles soluciones y valorar las potenciales ventajas e inconvenientes.Tres metodologías has sido específicamente desarrolladas para sacar el mayor rendimiento a la configuración en along-track del instrumento BBR. Se comprueba que la aplicación de ADMs teóricos sobre radiancias medidas desde satélite está todavía en un proceso inicial. Es, por tanto, prematuro utilizar ADMs teóricos, y se constata la necesidad de profundizar en el análisis de ADMs empíricos. La Tesis pone de manifiesto los problemas que surgen en la conversión al considerar escenas con varias capas de nubes si la identificación de escena no es precisa. Se demuestra la mejora en la conversión de radiancias a flujos cuando se realiza una adecuada definición de escena del ADM y se incluyen los productos de los sensores activos del EarthCARE en la identificación de escena del BBR.
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Franke, Tobias Alexander Verfasser], Dieter W. [Akademischer Betreuer] [Fellner, and Michael [Akademischer Betreuer] Wimmer. "The delta radiance field / Tobias Alexander Franke. Betreuer: Dieter W. Fellner ; Michael Wimmer." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://d-nb.info/1111911304/34.
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Beshr, Mahmoud Hassan Shaaban Mansour. "The performance of Visible Light Communication systems in the presence of sunlight radiance." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24841.
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Visible Light Communication has the potential to provide a licence free solution to implementing high data rate wireless communication within indoor environments. Although VLC systems offer many attractive features, a number of deployment barriers remain such as the impact of sunlight irradiance on performance, line-of-sight connections, uplink issues and the 'illumination on' operational mode. The research investigates the design of VLC systems in the presence of sunlight irradiance. The foundation of the investigation is a sunlight irradiance model that generates hourly levels of natural light intensity over the year for different locations. System behaviour over different metrological conditions and extended to consider the effect of cloud coverage, is analysed for a range of the most common surfaces found in indoor environments using Matlab and Monte Carlo simulations. The evaluation of system performance considers both Line-of-Sight and Non-Line-of-Sight components (up to the fifth reflection) at a range of data rates. A comparative analysis of system performance with reported results assuming noise owing to sunlight follows Gaussian statistics is conducted. Optimum placement of LED sources is investigated. System performance characterisation is conducted for different room sizes and as a function of distance from sources of sunlight such as windows and doors. Optimum LED layout maximises the SNR, fulfils the illumination constraint as governed IEC standards and minimises the variation of the SNR across the room. The design guidelines are applicable to any room size, LED specification, wall reflectivity, location and illumination level. An approach to managing the 'illumination on' scenario is developed. Operational performance as a function of the number of energised LEDs and LED panel layout for different room sizes, surface reflectivity, different operating conditions and applications is evaluated. In summary, the research provides an in depth analysis of VLC system performance in the presence of sunlight irradiance, the results forming the foundation for future system designs and applications.
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Franke, Tobias Alexander [Verfasser], Dieter W. [Akademischer Betreuer] Fellner, and Michael [Akademischer Betreuer] Wimmer. "The delta radiance field / Tobias Alexander Franke. Betreuer: Dieter W. Fellner ; Michael Wimmer." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://nbn-resolving.de/urn:nbn:de:tuda-tuprints-49921.
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Kim, Rhae Sung. "Estimating snow depth of alpine snowpack via airborne multifrequency passive microwave radiance observations." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503071052341111.
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Hall, Ashley Renee. "ENVISIONING ANTI-BLACK ABORTION RHETORIC: AN ANALYSIS OF THE RADIANCE FOUNDATION'S BILLBOARD CAMPAIGN." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/930.
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In contemporary society, public discourse about abortion remains substantially controversial. Although the U.S. abortion debate remains in the public eye, there has been little to no attention focused on race. This project interrogates the role of race and racial identity in the abortion debate through. To investigate the existence of race in contemporary U.S. abortion rhetoric, I utilize a three-part conceptual framework as my rhetorical method. I examine TRF billboard campaign, paying particular attention to its employment of collective memory. Moreover, I examine how the campaign uses African American collective memories to create and sustain an argument concerning Black abortion. I conclude that racialized abortion rhetoric demands scholarly attention because it extends the boundaries of conversations about abortion. Furthermore, I contend that anti-Black abortion rhetoric increases our understanding of how communication and racial/ethnic identities mutually develop.
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Neal, David A. "Maximum Likelihood Temperature/Emissivity Separation of Hyperspectral Images with Gaussian Distributed Downwelling Radiance." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5873.
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Hyperspectral images are made up of energy measurements at different wavelengths of light. The case is considered where these measurements are dependent on temperature, the self-emitted energy (emissivity), and reflected energy (downwelling radiance) from the surroundings. The process where the downwelling radiance is fixed and the temperature and emissivity are estimated is referred to as temperature/emissivity separation.
Due to the way these terms mix, for a given set of measurements, there exist many pairs of temperatures and emissivities that satisfy the model. This creates ambiguity in the solution that must be resolved for the result to have any significance.
A new model is developed which reduces this ambiguity. This model is used to form an objective function. The temperature and emissivity which maximize the value of the objective function are solved for given a set of measurements.
As part of the solution, a new algorithm is developed which exploits the shape of the objective function to estimate the temperature and emissivity quickly and accurately. Extensive testing of this algorithm is performed to gain an understanding of its average speed and accuracy.
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Francis, Mirvatte. "Contribution à la caractérisation des propriétés optiques des sables et des suies atmosphériques avec les instruments PROGRA2." Phd thesis, Université d'Orléans, 2011. http://tel.archives-ouvertes.fr/tel-00635379.
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Des nouvelles courbes de polarisation et de radiances en fonction de l'angle de diffusion sont étudiées à _ = 632,8 nm et 543,5 nm en utilisant des instruments PROGRA2 (Propriétés Optiques des GRains Astronomiques et Atmosphériques) pour différents types d'échantillons de suie et de noir de carbone en lévitation dans l'air et déposés sur une surface. Les échantillons de suie sont produits dans des conditions de combustion différentes, affectant ainsi leurs propriétés morphologiques. Un générateur de suie a été également utilisé pour étudier des suies 'jeunes' émises par la combustion du propane. Une comparaison des propriétés optiques entre les suies en lévitation et déposées sur une surface a été discutée. Enfin, ces courbes sont comparées à celles produites par différents types de sable. Les amplitudes de polarisation produites par la suie diffèrent en fonction du diamètre des particules primaires et de la distribution en taille. Ces courbes seules sont donc insuffisantes pour estimer la nature des agglomérats solides qui pourraient être détectés par des mesures à distance dans la stratosphère. D'autre part les courbes de radiance produites par ces échantillons montrent un comportement différent de celles produites par les échantillons de sable et par la poussière interplanétaire. Il est donc important lors de l'interprétation des mesures stratosphériques de combiner les courbes de radiances avec les courbes de polarisation pour déterminer la nature des agglomérats et de fournir des informations sur la nature de suie détectée telle que la taille des particules primaires ainsi que la distribution en taille.
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Sá, Jorge Paulo Duarte Hipólito de. "Media na arquitetura: intervenção e experiência visual em espaço contemplativo Nimbus Radiance Gate Project." Doctoral thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/14549.
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O aparecimento das novas tecnologias media abriu novos campos de inter-venção na Arquitetura criando uma nova dinâmica comunicacional na relação entre o espaço e o público onde estão presentes aparatos tecnológicos que permitem uma nova experiência sensorial, estética e até espiritual. Esta conexão torna pertinente a ideia de reabilitar espaços através das novas tecnologias media, como por exemplo espaços religiosos.
Esta investigação pretende criar um projeto Media integrado em espaço reli-gioso, explorando Arquitetura, Arte e Tecnologias media reforçando este campo mul-tidisciplinar. O projecto Media consiste na leitura crítica do lugar através da elabora-ção de um conceito simbólico e iconográfico relacionando o espaço contemplativo e um aparato media/arquitetónico, utilizando softwares de última geração. O projeto media, Nimbus Radiance Gate Project utiliza projeções 3D e sensores de movimento resultando numa dupla projeção holográfica; Abstract:
The appearance of the new Media technologies have opened new fields of in-tervention in architecture creating a new dynamic communication in the relationship between public and space, where are present technological devices that enable a new sensory experience, aesthetic and even espiritual.This connection makes rele-vant the idea of rehabilitate architectonic spaces with new media technologies such as sacred spaces.
This research aims to create a media project integrated in sacred spaces that combine Architecture, Art and New Technologies, exploring new perspectives and diferent dynamics in space.
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Blackwell, William Joseph 1971. "Atmospheric temperature profile estimation from infrared and microwave spectral radiance observations using principal components analysis." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11122.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Vita.
Includes bibliographical references (p. 123-127).
by William Joseph Blackwell.
M.S.
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Hungershöfer, Katja, and Thomas Trautmann. "Investigations into the impact of the lower boundary condition on the reflected solar radiance field." Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-217354.
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It is presented how the original isotropic boundary condition in a Gauss-Seidel radiative transfer model is generalized to describe an angular dependent surface reflection. A symmetry about the plane of incidence is assumed since the general case of an arbitrary non-symmetric reflection is to costly. As a result using Hapke\'s BRDF the upward radiance at the surface and the top of the atmosphere are discussed and compared to the results with the original isotropic boundary condition. In addition we discuss the impact of Rayleigh scattering and aerosol extinction on the reflected solar radiance fieldEs wird dargestellt wie die untere Randbedingung in unserem Gauss-Seidel Strahlungstransportmodell erweitert wird, um eine richtungsabhängige Reflexion beschreiben zu können. Da die Beschreibung einer asymmetrischen Bodenreflexion zu aufwendig wäre, beschränken wir uns dabei auf den Fall, bei dem die Reflexion symmetrisch bezüglich der Einfallsebene ist. Als Ergebnisse werden die aufwärtsgerichtete Strahldichte unmittelbar am Erdboden und am Atmosphärenoberrand diskutiert und mit den Ergebnissen für die ursprünglich isotrope Reflexion verglichen. Außerdem wird auf den Einfluß der Rayleigh Streuung und der Extinktion durch die Aerosolpartikel auf das reflektierte solare Strahldichtefeld eingegangen
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Hungershöfer, Katja, and Thomas Trautmann. "Investigations into the impact of the lower boundary condition on the reflected solar radiance field." Universität Leipzig, 2003. https://ul.qucosa.de/id/qucosa%3A15232.
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It is presented how the original isotropic boundary condition in a Gauss-Seidel radiative transfer model is generalized to describe an angular dependent surface reflection. A symmetry about the plane of incidence is assumed since the general case of an arbitrary non-symmetric reflection is to costly. As a result using Hapke\''s BRDF the upward radiance at the surface and the top of the atmosphere are discussed and compared to the results with the original isotropic boundary condition. In addition we discuss the impact of Rayleigh scattering and aerosol extinction on the reflected solar radiance field.Es wird dargestellt wie die untere Randbedingung in unserem Gauss-Seidel Strahlungstransportmodell erweitert wird, um eine richtungsabhängige Reflexion beschreiben zu können. Da die Beschreibung einer asymmetrischen Bodenreflexion zu aufwendig wäre, beschränken wir uns dabei auf den Fall, bei dem die Reflexion symmetrisch bezüglich der Einfallsebene ist. Als Ergebnisse werden die aufwärtsgerichtete Strahldichte unmittelbar am Erdboden und am Atmosphärenoberrand diskutiert und mit den Ergebnissen für die ursprünglich isotrope Reflexion verglichen. Außerdem wird auf den Einfluß der Rayleigh Streuung und der Extinktion durch die Aerosolpartikel auf das reflektierte solare Strahldichtefeld eingegangen.
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Humpage, Neil. "Observing and modelling the impact of arctic and tropical cirrus clouds on far-infrared radiance spectra." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5652.
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The work described in this thesis concerns the effect of cirrus clouds on far-infrared (FIR) radiance spectra. Though the importance of both FIR radiation and cirrus clouds to the Earth’s energy budget is well recognised, few high spectral resolution measurements have been made at FIR wavelengths to date. Observations taken during two diverse field campaigns, along with spectra simulated using a radiative transfer model, are used here to investi- gate the FIR signature of cirrus. The FIR observations presented are made using the TAFTS spectrometer, which measures spectral radiances from ei- ther an aircraft or the ground. The deployment of TAFTS during the RHUBC campaign based in Barrow, Alaska is described. TAFTS was used to make ground-based FIR observations of the arctic atmosphere, both with and without cirrus. Comparing these with modelled spectra, which assume a parameterised particle size distribution (PSD) when describing the cirrus microphysics, suggested that the PSD parameterisation underestimates the fraction of ice water content contributed by small ice crystals. This conclusion is corroborated by AERI-ER observations made simultaneously at the Barrow site during RHUBC. TAFTS observations of convective tropical cirrus made during EMERALD- II near Darwin, Australia are also presented here. During EMERALD-II TAFTS was deployed on an aircraft, enabling spectral measurements of cirrus at wavenumbers between 100 and 200cm−1 to be made for the first time. Comparisons with LBLDIS spectra calculated using PSDs measured using cloud probes indicate that the number of small crystals measured may be too high by a factor of three. This result is in agreement with previous studies suggesting that small crystal populations are over-counted by in-situ cloud probes, due to shattering of larger crystals on the probe inlets. The results from both campaigns illustrate the sensitivity of FIR radiances to cirrus properties, with particular emphasis on the effect of small ice crystals.
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Tohsing, Korntip [Verfasser]. "Derivation of sky luminance and spectral sky radiance from images taken with a CCD camera / Korntip Tohsing." Hannover : Technische Informationsbibliothek (TIB), 2014. http://d-nb.info/1130811050/34.
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Abuelgasim, Abdelgadir A. M. "Modelling bidirectional radiance measurements collected by the advanced solid-state array spectroradiometer over Oregon transect conifer forests." Thesis, Boston University, 1986. https://hdl.handle.net/2144/22548.
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Thesis (M.A.)--Boston UniversityThe primary objective of this research is to test and validate a geometric-optical bidirectional reflectance canopy model developed by Li and Strahler, with respect to actual forest canopy reflectance measurments. This model treats forest canopies as scenes of discrete, three dimensional objects that are illuminated and viewed from different positions in the hemisphere. The shapes of the objects, their count densities and patterns of placement are the driving variables, and they condition the mixture of sunlit and shaded objects and background that is observed from a particular viewing direction, given a direction of illumination. This mixture, in turn, controls the brightness apparent to an observer or a radiometric instrument. The Advanced Solid-State Array Spectroradiometer (ASAS) is chosen to be the sensor having the ability of collecting measurements at various look angles and its imaged reflectance was used to validate the model. The modelled BRF's were compared to actual ASAS measured BRF's in sites with different canopy structures and densities. The comparision revealed execellent match between the modelled and measured reflectance, and great ability of the model in predicting the shape and magnitude of the BRDF, in almost all the sites investigated. It is concluded that the geometric optics approach provided a good way to model the bidirectional reflectance distribution function of natural vegetation canopies, that captures the most important features exhibited by bidirectional measurements of such canopies. Further modifications have been suggested that will improve the predicted BRF's, and yield better results. [TRUNCATED]
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[Verfasser], Korntip Tohsing. "Derivation of sky luminance and spectral sky radiance from images taken with a CCD camera / Korntip Tohsing." Hannover : Technische Informationsbibliothek (TIB), 2014. http://nbn-resolving.de/urn:nbn:de:gbv:089-7751729366.
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Goldberg, Mitchell David. "The generation and applications of a spectrally resolved infrared radiance climatology derived from the atmospheric infrared sounder." College Park, Md.: University of Maryland, 2009. http://hdl.handle.net/1903/9231.
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Thesis (Ph.D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Atmospheric and Oceanic Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Golubev, Martin. "Program pro výpočet rozložení optické intenzity." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-219957.
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This diploma thesis deals with system for visible light communication (VLC). There are described basic optical elements like a electroluminescence diode and photodiode. In next chapter is described design of transmitter, optical channel and receiver. Attention is also devoted to modulation suitable for optical communication. The last chapter is devoted to program in Matlab language, which's name is Program for calculation of optical intensity distribution. That program was created in this diploma theses.
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Grob, Hans Christian [Verfasser], and Bernhard [Akademischer Betreuer] Mayer. "Aerosol remote sensing from ground-based polarized sky-radiance under cloudy conditions / Hans Christian Grob ; Betreuer: Bernhard Mayer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/120201139X/34.
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Da, Cheng. "An objective regional cloud mask algorithm for GOES infrared imager with regime-dependent thresholds for direct radiance assimilation." Thesis, The Florida State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1559511.
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A local, regime-dependent cloud mask (CM) algorithm is developed for isolating cloud-free pixels from cloudy pixels for Geostationary Operational Environmental Satellite (GOES) imager radiance assimilation using mesoscale forecast models. In this CM algorithm, thresholds for six different CM tests are determined by a one-dimensional optimization approach based on probability distribution functions of the nearby cloudy and clear-sky pixels within a 10o×10o box centered at a target pixel. It is shown that the optimized thresholds over land are in general larger and display more spatial variations than over ocean. The performance of the proposed CM algorithm is compared with Moderate Resolution Imaging Spectroradiometer (MODIS) CM for a one-week period from 19 to 23 May 2008. Based on MODIS CM results, the average Probability of Correct Typing (PCT) reaches 92.94% and 91.50% over land and ocean, respectively.
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Betancourt, Michael (Michael Joseph). "The radiance of the gluon spin : constraining the proton spin structure with the direct photon double helicity asymmetry." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/77493.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, February 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 131-136).
Although fundamental to the observable universe, the proton is not elementary. Rather the particle is a bound state of three valence quarks and the QCD vacuum that condenses around them, its properties an amalgamation of those underlying degrees of freedom. Naive expectations presume that contributions from the valence quarks dominate these properties, but the deep inelastic scattering (DIS) experiments which first investigated the proton structure in detail revealed the importance of the vacuum. In particular, polarized DIS measurements uncovered a surprisingly inadequate quark polarization, necessitating significant contributions to the proton spin from elsewhere. The total spin of the gluon field confining the quarks is one possibility, but a contribution only weakly constrained by the electromagnetic probes of DIS. An observable far more sensitive to contributions from the gluon field can be found in the collision of two polarized protons. By correlating the incident proton helicities with final-states originating from an initial-state gluon, the double-helicity asymmetry directly probes the underlying gluon polarization and provides much stronger experimental constraints. Asymmetries measured with hadronic final-states have already improved the understanding of the proton spin structure significantly, but with accumulating statistics these measurements will eventually be limited by systematic uncertainties. Although direct photons are rare in the hadronic environment, the simplicity of the resulting asymmetry ultimately promises a more precise probe of the gluon polarization. Located at the Relativistic Heavy Ion Collider (RHIC), the only facility in the world capable of accelerating and colliding polarized proton beams, the Solenoidal Tracker at RHIC (STAR) provides the large acceptance electromagnetic calorimetry and charged particle tracking critical for measuring direct photons and, subsequently, their asymmetry. Utilizing data from the 2009 running period with intricate simulation, state-of-the-art statistical methods have been developed to tease out the rare photon signal from an overwhelming hadronic background to enable the first direct photon measurements at STAR. This thesis details the construction of the unpolarized cross section and an initial double-helicity asymmetry, proving the feasibility of the direct photon program at the experiment.
by Michael Betancourt.
Ph.D.
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Riechelmann, Stefan [Verfasser]. "Simultaneous measurement of spectral sky radiance : development, characterization and validation of a non-scanning multidirectional spectroradiometer (MUDIS) / Stefan Riechelmann." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2014. http://d-nb.info/106300571X/34.
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Khattak, Sharafatullah. "Identification of sunglint areas in polar orbiting satellites imagery and determination of near-surface wind speed from sunglint radiance." Thesis, University of Dundee, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340906.
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Schäfer, Michael. "Optical Thickness Retrievals of Subtropical Cirrus and Arctic Stratus from Ground-Based and Airborne Radiance Observations Using Imaging Spectrometers." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-207395.
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The development and application of new cloud retrieval methods from ground–based and airborne measurements of spectral radiance fields above heteorogeneous surfaces is introduced. The potential of imaging spectrometers in remote–sensing applications is evaluated. The analyzed spectral radiance fields were measured during two international field campaigns in the visible wavelength range (400–970 nm) with high spatial (<10m) resolution. From ground–based measurements, high ice clouds were observed and from airborne measurements Arctic stratus. From the measurements, cloud optical thickness is retrieved with high spatial resolution and the horizontal cloud inhomogeneities are investigated. Depending on the measurement configuration, different uncertainties arise for the retrieval of the cloud optical thickness. A reduction of those uncertainties is derived by a specification of the ice crystal shape to improve the retrieval of the optical thickness of high ice clouds. The ice crystal shape is obtained independently from the angular information of the scattering phase function features, imprinted in the radiance fields. A performed sensitivity study reveals uncertainties of up to 90%, when neglecting this information and applying a wrong crystal shape to the retrieval. For remote-sensing of Arctic stratus, the highly variable surface albedo influences the accuracy of the cloud optical thickness retrieval. In cloudy cases the transition of reflected radiance from open water to sea ice is not instantaneous but horizontally smoothed. In general, clouds reduce the reflected radiance above bright surfaces in the vicinity of open water, while it is enhanced above open sea. This results in an overestimation of to up to 90% in retrievals of the optical thickness. This effect is investigated. Using observations and three-dimensional radiative transfer simulations, this effect is quantified to range to up to 2200 m distance to the sea-ice edge (for dark-ocean albedo of αwater = 0.042 and sea-ice albedo of αice = 0.91 at 645 nm wavelength) and to depend on macrophysical cloud and sea-ice properties. The retrieved fields of cloud optical thickness are statistically investigated. Auto–correlation functions and power spectral density analysis reveal that in case of clouds with prevailing directional cloud structures, cloud inhomogeneities cannot be described by a universally valid parameter. They have to be defined along and across the prevailing cloud structures to avoid uncertainties up to 85%Im folgenden wird die Entwicklung und Anwendung neuer Ableitungsverfahren von Wolkenparametern, basierend auf bodengebundener und flugzeuggetragener spektraler Strahldichtemessungen über heterogenen Untergründen, vorgestellt und das Fernerkundungspotential abbildender Spektrometer evaluiert. Die spektralen Strahldichtefelder wurden während zweier internationaler Feldkampagnen im sichtbaren Wellenlängenbereich (400–970 nm) mit hoher räumlich Auflösung (<10m) gemessen. Bodengebundene Messungen wurden genutzt, um hohe Eiswolken zu beobachten und flugzeuggetragenen um arktischen Stratus zu beobachten. Aus den Messungen werden räumlich hochaufgelöste wolkenoptische Dicken abgeleitet und anschließend horizontale Wolkeninhomogenitäten untersucht. Die Ableitung der wolkenoptischen Dicke birgt je nach Messkonfiguration verschiedene Unsicherheiten. Eine Reduzierung der Unsicherheiten wird durch die Vorgabe einer Eiskristallform zur Verbesserung der Ableitung der optischen Dicke hoher Eiswolken erreicht. Diese werden unabhängig aus den winkelabhängigen, in das gemessene Strahldichtefeld eingeprägten Eigenschaften der Streuphasenfunktion, abgeleitet. Bei Vernachlässigung dieser Information und Wahl der falschen Eiskristallform, treten Fehler in der abgeleiteten optischen Dicke von bis zu 90% auf. Bei der Fernerkundung von arktischem Stratus beeinflusst die sehr variable Bodenalbedo die Genauigkeit der Ableitung der optischen Dicke. Beim Übergang von Meereis zu Wasser, findet die Abnahme der reflektierten Strahldichte im bewölktem Fall nicht direkt über der Eiskante, sondern horizontal geglättet statt. Allgemein reduzieren Wolken die reflektierte Strahldichte über Eisflächen nahe Wasser, während sie über dem Wasser erhöht wird. Dies führt zur Überschätzung der wolkenoptischen Dicke über Wasserflächen nahe Eiskanten von bis zu 90 %. Dieser Effekt wird mit Hilfe von Beobachtungen und dreidimensionalen Strahlungstransferrechnungen untersucht und es wird gezeigt, dass sein Einfluss noch bis zu 2200 m Entfernung zur Eiskante wirkt (für Meeresalbedo 0.042 und Meereisalbedo 0.91 bei 645 nm Wellenlänge) und von den makrophysikalischen Wolken- und Meereiseigenschaften abhängt. Die abgeleiteten Felder der optischen Dicke werden statistisch ausgewertet, um die Inhomogeneität der Wolken zu charakterisieren. Autokorrelationsfunktionen und Leistungsdichtespektren zeigen, dass Inhomogenitäten von Wolken mit vorranging richtungsabhängiger Struktur nicht mit einem allgemeingültigen Parameter beschrieben werden können. Es sind Inhomogenitätsmaße entlang und entgegen der jeweiligen Wolkenstrukturen nötig, um Fehler von bis zu 85% zu vermeiden