Dissertations / Theses on the topic 'Photometric image'
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Cuesta, Contreras Angel. "Geometric and photometric affine invariant image registration." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2228.
Full textGuillemaut, Jean-Yves. "Contributions to image-based object reconstruction : geometric and photometric aspects." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/527103/.
Full textLi, Boren. "Photometric stereo for micro-scale shape reconstruction." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/75021.
Full textPh. D.
Carassou, Sébastien. "Inferring the photometric and size evolution of galaxies from image simulations." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066382/document.
Full textCurrent constraints on the luminosity and size evolution of galaxies rely on catalogs extracted from multi-band surveys. However resulting catalogs are altered by selection effects difficult to model and that can lead to conflicting predictions if not taken into account properly. In this thesis we have developed a new approach to infer robust constraints on model parameters. We use an empirical model to generate a set of mock galaxies from physical parameters. These galaxies are passed through an image simulator emulating the instrumental characteristics of any survey and extracted in the same way as from observed data for direct comparison. The difference between mock and observed data is minimized via a sampling process based on adaptive Monte Carlo Markov Chain methods. Using mock data matching most of the properties of a Canada-France-Hawaii Telescope Legacy Survey Deep (CFHTLS Deep) field, we demonstrate the robustness and internal consistency of our approach by inferring the size and luminosity functions and their evolution parameters for realistic populations of galaxies. We compare our results with those obtained from the classical spectral energy distribution (SED) fitting method, and find that our pipeline infers the model parameters using only 3 filters and more accurately than SED fitting based on the same observables. We then apply our pipeline to a fraction of a real CFHTLS Deep field to constrain the same set of parameters in a way that is free from systematic biases. Finally, we highlight the potential of this technique in the context of future surveys and discuss its drawbacks
Forne, Christopher Jes. "3-D Scene Reconstruction from Multiple Photometric Images." Thesis, University of Canterbury. Electrical and Computer Engineering, 2007. http://hdl.handle.net/10092/1227.
Full textYoonessi, Ali. "The role of natural image structure in visual detection of photometric changes." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21997.
Full textLe rôle de la structure des images naturelles dans la sensibilité visuelle aux changements photométriques uniformes Chez l'être humain, les changements dans la sensibilité visuelle aux contrastes chromatiques et achromatiques, appelés changements photométriques, sont traditionnellement mesurés à l'aide de stimuli simples tels que des disques ou des réseaux de bars. Les résultats de ces études reposent généralement sur des mécanismes de bas-niveau tels que les filtres quasi-linéaires du cortex visuel, qui prédisent que la structure des scènes naturelles ne devrait pas influencer la sensibilité aux changements photométriques. D'un autre coté a été émise l'hypothèse selon laquelle le système visuel est optimisé pour l'analyse de l'information présente dans les scènes naturelles, ce qui suggère que la structure unique des scènes naturelles pourrait influencer la sensibilité aux changements photométriques. Nous avons donc testé ces deux hypothèses en comparant la sensibilité aux changements photométriques uniformes pour des scènes naturelles dont la structure est soit restée intacte, soit éliminée par l'intermédiaire d'un brouillage de leur information de phase. Les résultats de cette étude démontrent que la sensibilité est plus grande pour les scènes naturelles intactes que leurs versions ‘brouillées'. Des expériences complémentaires excluent la possibilité que la sensibilité plus élevée pour les scènes naturelles soit due à une familiarisation à leurs couleurs, ou la possibilité que la sensibilité plus faible pour leurs versions brouillées soit due à l'augmentation de la variabilité chromatique induite par le brouillage de phase. Dans une autre série d'expériences, la sensibilité aux changements photométriques uniformes pour les scènes intactes et brouillées a été mesurée pour des paires d'images présentées dichoptiquement et pour lesquelles les changements photométriques ont été appliqu
Cartwright, Stephen J. "Application of digital image processing techniques to the photometric testing of vehicle headlamps." Thesis, Aston University, 1986. http://publications.aston.ac.uk/14614/.
Full textZou, Hu, Tianmeng Zhang, Zhimin Zhou, Jundan Nie, Xiyan Peng, Xu Zhou, Linhua Jiang, et al. "The First Data Release of the Beijing-Arizona Sky Survey." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624694.
Full textPekelsky, James Regan Carleton University Dissertation Engineering Electrical. "The automated ordering of moire fringe contours using local photometric modelling of surface shading." Ottawa, 1988.
Find full textBakthavatchalam, Manikandan. "Utilisation of photometric moments in visual servoing." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S057/document.
Full textThis thesis is concerned with visual servoing, a feedback control technique for controlling camera-equipped actuated systems like robots. For visual servoing, it is essential to synthesize visual information from the camera image in the form of visual features and establish the relationship between their variations and the spatial motion of the camera. The earliest visual features are dependent on the extraction and visual tracking of geometric primitives like points and straight lines in the image. It was shown that visual tracking and image processing procedures are a bottleneck to the expansion of visual servoing methods. That is why the image intensity distribution has also been used directly as a visual feature. Finally, visual features based on image moments allowed to design decoupled control laws but they are restricted by the availability of a well-segmented regions or a discrete set of points in the scene. This work proposes the strategy of capturing the image intensities not directly, but in the form of moments computed on the whole image plane. These global features have been termed photometric moments. Theoretical developments are made to derive the analytical model for the interaction matrix of the photometric moments. Photometric moments enable to perform visual servoing on complex scenes without visual tracking or image matching procedures, as long as there is no severe violation of the zero border assumption (ZBA). A practical issue encountered in such dense VS methods is the appearance and disappearance of portions of the scene during the visual servoing. Such unmodelled effects strongly violate the ZBA assumption and can disturb the control and in the worst case, result in complete failure to convergence. To handle this important practical problem, an improved modelling scheme for the moments that allows for inclusion of spatial weights is proposed. Then, spatial weighting functions with a specific structure are exploited such that an analytical model for the interaction matrix can be obtained as simple functions of the newly formulated moments. A part of this work provides an additional contribution towards the problem of simultaneous control of rotational motions around the image axes. The approach is based on connecting the design of the visual feature such that the visual servoing is optimal with respect to specific criteria. Few selection criteria based on the interaction matrix was proposed. This contribution opens interesting possibilities and finds immediate applications in the selection of visual features in image moments-based VS
Bokaris, Panagiotis-Alexandros. "Video-projected augmented reality : Photometric compensation for static and dynamic concealment." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS453/document.
Full textThis thesis develops new approaches for human presence concealment and revelation using augmented reality techniques. It focuses on projector-camera systems (ProCams) and their application in “smart projections”, where the projected virtual content is adapted according to the environment. One previously-studied problem is the photometric compensation for projecting on a colored fixed surface that allows the viewer to observe the same image as it would appear on a white surface. Despite the various methods for color compensation that have been proposed the last decade, compensation on a real-world surface with saturated colors and sharp color boundaries is still an open issue. The main objective of this work is the color compensation on a moving 3D object using a ProCam, which is a dramatically more challenging scenario. A novel method for color compensation using a single input frame is proposed. It consists in estimating the spectral reflectance of the surface in order to compensate for it under the assumption that the projector responses are known or previously measured. This method was fully developed on GPU to enable real-time compensation. Previous methods on color compensation are discussed and compared in order to evaluate the performance of our technique. The accurate photometric and geometric calibration of a ProCam is essential for precise compensation. A new geometric calibration technique between a depth sensor and a ProCam is presented in order to make the projection on a moving object feasible. A photometric calibration is described for the transformation of the device-dependent camera and projector values to the device-independent CIE XYZ 1931 color space. The artistic potential of the proposed augmented reality techniques is further explored through the interactive art installation “Gardien du Temple”. Revelation and concealment has always been a common experimentation ground for both artists and scientists. This audio visual installation uses augmented reality to hide the presence of a written poem on a carpet inviting the spectator to reveal it. In such applications, the accuracy and robust performance of the methods employed is crucial and, thus, it offered a challenging ground for testing and evaluation
Sunkavalli, Kalyan. "Models of Visual Appearance for Analyzing and Editing Images and Videos." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10285.
Full textEngineering and Applied Sciences
Reyes, Gomez Juan Pablo. "Astronomical image processing from large all-sky photometric surveys for the detection and measurement of type Ia supernovae." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0144.
Full textThis thesis will present several contributions to the software developed for the LSST telescope with the purpose of contributing to the detection of type Ia supernovae. Our objective is to use the existing LSST code and algorithms, in order to create a type Ia supernovae detection dedicated pipeline.Since detecting supernovae requires a special type of processing, we use a technique known as the Optimal Image Subtraction which implies the construction of coadditions. Afterwards, we study the behavior of the different objects through time and build light curves that represent their life cycle in terms of the light intensity of each detection on several nights. Lastly, in order to analyze an excessive number of candidates, we employ machine learning algorithms to identify what curves are more probable to be type Ia supernovae. Our first contribution concerns the development of adapted and automatized coaddition tasks for building high signal-to-noise reference and science images. The next contribution is related to the addition of measurements and study of the residuals on difference image analysis, including the selection with adapted thresholding and the assignation of labels. We also propose, as contributions, an algorithm to select and generate the different candidate light curves through the selection of objects with recurrent detections through time and in the different bandpasses. Finally, we apply the machine learning classification approach to find type Ia supernovae by means of using a random forest classifier and based strictly on geometrical features that are present in the light curves
Moore, Thomas Brendan. "Learning Geometry-Free Face Re-lighting." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3353.
Full textM.S.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science MS
Bony, Alexandre. "Modélisation de l'interaction lumière/matière pour l'analyse de surfaces rugueuses texturées par stéréo photométrie." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2301/document.
Full textTridimensional reconstruction method has become essential for applications suchas the characterization and analysis of surfaces. In this thesis, aims are to increase the qualityof 3d reconstructions by photometric stereo. This method is based on two principles, reversinglight-matter interaction model and configuration of a lighting system. With diffuse surfaces,the photometric stereo use three captured images from a fixed point of view for differentillumination directions. Its main advantage is to extract the color and geometric propertiesfor the textured rough surfaces. However, its application requires to make assumptions thatare not credible in real cases. This problem generates significant errors in the reconstructions.To reduce them, we offer various solutions around the overall consideration of the acquisitionchain. Our contribution focuses on the characterization and modeling of the lighting system,the acquisition sensor and improved image quality. We are also interested to optimize acquisitionprotocol in the case of specular surface or shading due to the surface geometry. Ourresults show that the inclusion of these features in the inversion of a BRDF model allowsan improvement of 3d reconstructions as well as the possibility of reducing the size of theacquisition systems
Lladó, Bardera Xavier. "Texture recognition under varying imaging geometries." Doctoral thesis, Universitat de Girona, 2004. http://hdl.handle.net/10803/7721.
Full textLa Visió per Computador intenta emular el sistema de visió humà mitjançant un sistema de captura d'imatges, un ordinador, i un conjunt de programes. L'objectiu desitjat no és altre que desenvolupar un sistema que pugui entendre una imatge d'una manera similar com ho realitzaria una persona.
Aquesta tesi es centra en l'anàlisi de la textura per tal de realitzar el reconeixement de superfícies. La motivació principal és resoldre el problema de la classificació de superfícies texturades quan han estat capturades sota diferents condicions, com ara distància de la càmera o direcció de la il·luminació. D'aquesta forma s'aconsegueix reduir els errors de classificació provocats per aquests canvis en les condicions de captura.
En aquest treball es presenta detalladament un sistema de reconeixement de textures que ens permet classificar imatges de diferents superfícies capturades en diferents condicions. El sistema proposat es basa en un model 3D de la superfície (que inclou informació de color i forma) obtingut mitjançant la tècnica coneguda com a 4-Source Colour Photometric Stereo (CPS). Aquesta informació és utilitzada posteriorment per un mètode de predicció de textures amb l'objectiu de generar noves imatges 2D de les textures sota unes noves condicions. Aquestes imatges virtuals que es generen seran la base del nostre sistema de reconeixement, ja que seran utilitzades com a models de referència per al nostre classificador de textures.
El sistema de reconeixement proposat combina les Matrius de Co-ocurrència per a l'extracció de característiques de textura, amb la utilització del Classificador del veí més proper. Aquest classificador ens permet al mateix temps aproximar la direcció d'il·luminació present en les imatges que s'utilitzen per testejar el sistema de reconeixement. És a dir, serem capaços de predir l'angle d'il·luminació sota el qual han estat capturades les imatges de test.
Els resultats obtinguts en els diferents experiments que s'han realitzat demostren la viabilitat del sistema de predicció de textures, així com del sistema de reconeixement.
This thesis is concerned with the application of texture analysis to discriminate between textured surfaces. The main motivation is the problem of classifying textured surfaces imaged under varying geometries, i.e. distance from the sensor and illumination direction, as well as the necessity of finding reliable methods of reducing classification errors caused by changes in the geometry's properties.
In texture analysis one must distinguish between image texture and surface texture. Image texture is what appears in the 2D image of a physical object, while surface texture refers to the variation of the physical and geometric properties of the imaged surface which give rise to the image texture. Changes in the imaging geometry can significantly alter the appearance of the surface, implying significant variations in the image texture. And one still has to perform the task of recognition from the image texture.
In this thesis, after analysing different strategies, we integrate the surface texture information derived by colour photometric stereo (CPS) into a complete model-based texture classification system. Photometric stereo is the technique which allows us to obtain surface texture information from a few images of the same surface imaged under various illumination directions. Basically, the main idea of our strategy consists of creating, by means of the surface texture information, a virtual' database of image textures against which we compare unknown test images in order to classify them. Note that we do not use the surface texture information directly to perform classification, but we use it to create new images which are the references for our training and classification process. Furthermore, the classification system allows us to guess the approximate direction of the illumination used to capture the test images.
The proposed prediction methods, as well as the model-based texture classification system, are tested and evaluated. A set of real surface textures containing a wide variety of relatively smooth and very rough surfaces are used in this thesis as our image database.
Mazin, Baptiste. "Méthodes robustes pour l'estimation d'illuminants et la prise en compte de la couleur en comparaison d'images." Thesis, Paris, ENST, 2014. http://www.theses.fr/2014ENST0016/document.
Full textThis thesis addresses the use of color in image processing and computer vision. Two problems are studied: - illuminant estimation, - local descriptors matching for color images comparison. Achromatic surfaces are defined as surfaces reflecting a spectrum with the same frequency dsitribution than the illuminant. Consequently, revovering these surfaces allows to estimate the illuminant. Assuming that the range of colors taken by an illuminant is limited (Planck equation), it is possible to select the pixels belonging to a potentially gray surface. A voting procedure is then applied to select one or more illuminants. The proposed algorithm has many advantages: it is effective, intuitive, does not rely on a learning phase and requires only few parameters. In addition, the voting procedure can be adapted to handle cases where multiple light sources of different colors illuminate the scene. Local descriptors are powerful tools to compare images. However, few studies concern the influence of color in the matching step. The main problem that we consider here is the contribution of the color matching of local descriptors. Does the local use of color allow to disambiguate situations where the luminance alone is insufficient ? And if so, how much? We propose four descriptors to precisely describe the local context of key points in the matching step. The main idea developed here is that accurate information can only be obtained by describing both the color distributions and transitions between colors. The many experiences presented clearly show the positive contribution of color to the reliability of the local matching
Heinz, Marcel. "Kalibrierverfahren und optimierte Bildverarbeitung für Multiprojektorsysteme." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-129508.
Full textTan, Ping. "3D modeling from photometry and geometry /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CSED%202007%20TAN.
Full textChari, Visesh. "Shape estimation of specular objects from multiview images." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENM106/document.
Full textThe task of understanding, 3D reconstruction and analysis of the multiple view geometry related to transparent objects is one of the long standing challenging problems in computer vision. In this thesis, we look at novel approaches to analyze images of transparent surfaces to deduce their geometric and photometric properties. At first, we analyze the multiview geometry of the simple case of planar refraction. We show how the image of a 3D line is a quartic curve in an image, and thus derive the first imaging model that accounts for planar refraction. We use this approach to then derive other properties that involve multiple cameras, like fundamental and homography matrices. Finally, we propose approaches to estimate the refractive surface parameters and camera poses, given images. We then extend our approach to derive algorithms for recovering the geometry of multiple planar refractive surfaces from a single image. We propose a simple technique to compute the normal of such surfaces given in various scenarios, by equating our setup to an axial camera. We then show that the same model could be used to reconstruct reflective surfaces using a piecewise planar assumption. We show encouraging 3D reconstruction results, and analyse the accuracy of results obtained using this approach. We then focus our attention on using both geometric and photometric cues for reconstructing transparent 3D surfaces. We show that in the presence of known illumination, we can recover the shape of such objects from single or multiple views. The cornerstone of our approach are the Fresnel equations, and we both derive and analyze their use for 3D reconstruction. Finally, we show our approach could be used to produce high quality reconstructions, and discuss other potential future applications
Hansson, Peter. "Surface Characterization using Radiometric and Fourier Optical Methods." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3569.
Full textDemitri, Nevine [Verfasser], Abdelhak M. [Akademischer Betreuer] Zoubir, and Hamid [Akademischer Betreuer] Krim. "Signal and Image Processing Techniques for Image-Based Photometry With Application to Diabetes Care / Nevine Demitri. Betreuer: Abdelhak M. Zoubir ; Hamid Krim." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1113183470/34.
Full textAckermann, Jens [Verfasser], Michael [Akademischer Betreuer] Goesele, and Reinhard [Akademischer Betreuer] Klein. "Photometric Reconstruction from Images: New Scenarios and Approaches for Uncontrolled Input Data / Jens Ackermann. Betreuer: Michael Goesele ; Reinhard Klein." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2014. http://d-nb.info/1110978979/34.
Full textБезуглий, Михайло Олександрович. "Еліпсоїдальні рефлектори для фотометрії біологічних середовищ." Thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/31490.
Full textThe thesis is devoted to the solution of the important scientifically applied problem of development the construction and application method of ellipsoidal reflectors in the registration and analysis systems of scattered optical radiation, as well as approbation of new structural, functional and biomedical solutions. This made it possible to theoretically and experimentally substantiate the method and hardware of the use the ellipsoidal reflectors for photometry of light scattering by biological media in the detection of their optical properties and identification of physical and physiological state. A fundamental basis for solving this problem is the first-time developed mechanism of ray-tracing, which colligate the parameters of the radiation source, biological media, ellipsoidal reflector and matrix photodetector in the information-measuring system of biomedical photometer, which allows to solve the direct and inverse problems of light propagation by the Monte Carlo statistical simulation. The main content of the thesis is outlined in eight chapters, which present and substantiate the goal and results of the work. The first chapter presents the results of analytical review and literary search, which reveal the tasks raised in the doctorate thesis. In particular, the methods of biophotonics that are most commonly used in the study of different biological media are given. The features of optical radiation propagation in biological media are analyzed, as well as the basic principles of the transfer radiative theory, which mathematically and analytically interpret this process. Typical photometric tools used for the study of biological media, boundary conditions of their use, and functional limitations are analyzed. The second chapter is devoted to the development a method of investigation the biological media optical properties. Structural schemes of basic photometers with ellipsoidal reflectors and features of their functioning are presented. The mathematical apparatus for calculating the ray tracing in a reflector with an internal ellipsoidal reflecting surface is presented, and the main types of ray trajectories are considered. The algorithm of the proposed mechanism of ray tracing and the features of its software are presented. The results of aberration analysis of ellipsoidal reflector are shown. The third chapter is devoted to the development of Monte Carlo models of light propagation in the information-measuring system of biomedical photometer with ellipsoidal reflectors. The features of the input data formation and the basic simulation algorithm are substantiated, as well as the boundary conditions of simulation. The analytical models of software adaptation of radiation source parameters, the receiving system, as well as the boundaries and scattering-absorption properties of the biological media that underlie the simulation are presented. The principles of determination the optical coefficients, algorithm and grounds of software implementation of Monte Carlo simulation in the system "radiation source + biological media + measuring tool" are presented. In the fourth chapter proposed the features of designing photometers with ellipsoidal reflectors by improving the standard equipment for microscopy, as well as in the construction of individual prototypes. Schemes of zone analysis at processing of photometric images obtained by photometry by ellipsoidal reflectors are considered. Mathematical and analytical aspects of solving the inverse problem of the radiative transfer theory by methods of Kubelka-Munk and inverse Monte-Carlo in the context the work of biomedical photometers with ellipsoidal reflectors operating in reflected and also in reflected and transmitted light are presented. The interrelation of photometric images and optical properties of the investigated biological media is considered. In the fifth chapter discusses the technological principles of ellipsoidal reflectors production and control. The materials choice of ellipsoid for different methods of shaping the aspherical surface is substantiated. The principles of production of metallic mirror ellipsoids of revolution using vertical-boring technology, as well as 3D printing technology from plastic are formulated. Practical aspects of applying a mirror coating to the inner ellipsoidal surface from plastic are determined. The analytical model and technical stages the shape control of the ellipsoidal surface are presented and photometric comparison of the functioning of reflectors produced by different technologies is made. The sixth chapter is devoted to the analysis of the effects of light scattering in the system "radiation source + biological media + measuring tool" for different profiles of energy distribution in the laser beam and their effect on the relative illuminance distribution of photometric image at zone analysis for different layers of human skin. The influence the parameters of ellipsoidal reflectors on the boundary geometric properties of optical radiation in the forward and backscattered light is considered. The influence the diameter and power of the incident beam at the tasks of Raman spectroscopy by ellipsoidal reflectors is also substantiated. In the seventh chapter features of application the photometry by ellipsoidal reflectors for creation and improvement tools of biological and medical diagnostics and control are shown. The influence of the scattering anisotropy factor on the illuminance of photometric images and the possibility of biomedical goniophotometry were evaluated. A measurement system for angular photometry in backscattered light was developed and investigated. Based on the model experiment, the prospects of using a photometer with ellipsoidal reflectors to control the optical clearing of human skin were evaluated. A prototype optical non-invasive glucometer with ellipsoidal reflectors was created and its functional features were investigated. The eighth chapter discusses the prospects of applying the mirror ellipsoids of revolution method for various problems in optical biomedical diagnostics.
В работе решен комплекс задач, позволивший решить важную научно-прикладную проблему разработки метода построения и применения эллипсоидальных рефлекторов в системах регистрации и анализа рассеянного оптического излучения, а также апробации новых конструктивных, функциональных и медико-биологических решений. Это позволило теоретически и экспериментально обосновать метод и аппаратные средства применения эллипсоидальные рефлекторов для фотометрии светорассеяния биологическими средами при обнаружении их оптических свойств и идентификации физического и физиологического состояния. Предложено фундаментальную основу решения указанной проблемы за счет впервые разработанного механизма рей-трейсинга, что взаимно связывает параметры источника излучения, биологической среды, эллипсоидального зеркала и матричного приемника излучения в информационно-измерительной системе биомедицинского фотометра с эллипсоидальными рефлекторами, и который позволяет решать прямую и инверсную задачи распространения оптического излучения методом статистического моделирования Монте-Карло.
Kyrgyzova, Khrystyna. "Stéréophotométrie non-calibrée de surfaces non-Lambertiennes. Application à la reconstruction de surface de colonies microbiennes." Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01063285.
Full textDiaz, Mauricio. "Analyse de l'illumination et des propriétés de réflectance en utilisant des collections d'images." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENM051/document.
Full textThe main objective of this thesis is to exploit the photometric information avail- able in large photo collections of outdoor scenes to infer characteristics of the illumination, the objects and the cameras. To achieve this goal two problems are addressed. In a preliminary work, we explore opti- mal representations for the sky and compare images based on its appearance. Much of the information perceived in outdoor scenes is due to the illumination coming from the sky. The solar beams are reflected and refracted in the atmosphere, creating a global illumination ambiance. In turn, this environment determines the way that we perceive objects in the real world. Given the importance of the sky as an illumination source, we formulate a generic 3–step process in order to compare images based on its appearance. These three stages are: segmentation, modeling and comparing of the sky pixels. Different approaches are adopted for the modeling and comparing phases. Performance of the algorithms is validated by finding similar images in large photo collections. A second part of the thesis aims to exploit additional geometric information in order to deduce the photometric characteristics of the scene. From a 3D structure recovered using available multi–view stereo methods, we trace back the image formation process and estimate the models for the components involved on it. Since photo collections are usually acquired with different cameras, our formulation emphasizes the estimation of the radiometric calibration for all the cameras at the same time, using a strong prior on the possible space of camera response functions. Then, in a joint estimation framework, we also propose a robust computation of the global illumination for each image, the surface albedo for the 3D structure and the radiometric calibration for all the cameras
Aljassim, Mohammad A. "A 6-Year Study of Long Period Variable Stars in the Globular Cluster NGC 6388." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1499442952467274.
Full textDamerdji, Yassine. "Recherche systématique de variabilités dans les images du télescope TAROT : application à la détection automatisée de l'émission optique des sursauts gamma." Toulouse 3, 2007. http://www.theses.fr/2007TOU30031.
Full textOptimal monitoring of gamma ray bursts with large telescopes requires accurate position and magnitude derived from rapid and automatic observations carried out with smaller optical telescopes. During this thesis, we set up an automatic method to select the most likely gamma ray burst optical counterparts based on the very first TAROT observations of gamma ray burst alert fields. Moreover, we completed the TAROT data pipeline to construct a large photometric measurement database, easily accessible by the community, and updated in real time by daily TAROT observations. From this database, we identified variable star candidates and searched for periodicity in their light curves using appropriate methods for unevenly sampled time series. Our data pipeline is optimised for the TAROT telescope, but could be easily set up for other astronomical projects of photometry
Walker, Christina H. "Monte Carlo radiation transfer studies of protoplanetary environments." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/218.
Full textBoulenguez, Pierre. "Caractérisation multispectrale imageante du champ de lumière de sources et de matériaux pour la photosimulation." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00587367.
Full textBelgacem, Ines. "Etude photométrique des lunes glacées de Jupiter." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS386/document.
Full textJupiter's icy moons are of great interest in the search for habitability in our Solar System. They probably all harbor liquid water ocean underneath their icy crust. Their surfaces present different stages of evolution – Callisto is heavily cratered and the oldest, Ganymede shows a combination of dark cratered terrain and younger bright plains and Europa’s surface is the youngest with signs of recent and maybe current activity. This work focuses on photometry, i.e. the study of the light scattered by a surface in relation to the illumination and observation geometry. Photometric studies give us insight on the physical state and microtexture of the surface (compaction, internal structure, shape, roughness, transparency…). A good photometric knowledge is also of crucial importance in the correction of datasets for any mapping or spectroscopic study as well as for the future missions of this decade – NASA’s Europa Clipper and ESA’s JUpiter ICy moons Explorer.Two pieces of information are necessary to conduct a photometric study – reflectance data and geometric information (illumination, viewing conditions). For the former, we have used and calibrated images from past space missions – Voyager, New Horizons and Galileo. For the latter, we have developed tools to correct these images metadata (e.g. spacecraft position and orientation) to derive precise geometric information. Moreover, we have developed a Bayesian inversion tool to estimate Hapke’s photometric parameters on regions of Europa, Ganymede and Callisto. We estimate all parameters on our entire dataset at once. Finally, we discuss the possible links between the photometric parameters, the surface microtexture and endogenic/exogenic processes
Harder, Stephan. "Reconstruction de la réponse impulsionnelle du système d'optique adaptative ADONIS à partir des mesures de son analyseur de surface d'onde et étude photométrique de la variabilité des étoiles YY Orionis." Phd thesis, Université Joseph Fourier (Grenoble), 1999. http://tel.archives-ouvertes.fr/tel-00686688.
Full textTrentacoste, Matthew. "Photometric image processing for high dynamic range displays." Thesis, 2006. http://hdl.handle.net/2429/17558.
Full textScience, Faculty of
Computer Science, Department of
Graduate
"Efficient photometric stereo on glossy surfaces with wide specular lobes." 2008. http://library.cuhk.edu.hk/record=b5893633.
Full textThesis (M.Phil.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 40-43).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Lambertian photometric stereo --- p.1
Chapter 1.2 --- Non-Lambertian photometric stereo --- p.3
Chapter 1.3 --- Large specular lobe problems --- p.4
Chapter 2 --- Related Work --- p.9
Chapter 2.1 --- Lambertian photometric stereo --- p.9
Chapter 2.2 --- Non-Lambertian photometric stereo --- p.9
Chapter 2.2.1 --- Analytic models to reconstruct non-Lambertian surface --- p.9
Chapter 2.2.2 --- Reference object based --- p.10
Chapter 2.2.3 --- Highlight removal before shape reconstruction --- p.11
Chapter 2.2.4 --- Polarization based method --- p.12
Chapter 2.2.5 --- Specularity fitting method --- p.12
Chapter 2.2.6 --- Photometric stereo with shadow --- p.12
Chapter 3 --- Our System --- p.13
Chapter 3.1 --- Estimation of global parameters --- p.14
Chapter 3.1.1 --- Shadow separation --- p.16
Chapter 3.1.2 --- Separation edges of shadow and edges of foreground object --- p.16
Chapter 3.1.3 --- Normal estimation using shadow boundary --- p.20
Chapter 3.1.4 --- Global parameter estimation and refinement --- p.22
Chapter 3.2 --- Surface shape and texture reconstruction --- p.24
Chapter 3.3 --- Single material results --- p.25
Chapter 4 --- Comparison between Our Method and Direct Specularity Fitting Method --- p.29
Chapter 4.1 --- Summary of direct specularity fitting method [9] --- p.29
Chapter 4.2 --- Comparison results --- p.31
Chapter 5 --- Reconstructing Multiple-Material Surfaces --- p.33
Chapter 5.1 --- Multiple material results --- p.34
Chapter 6 --- Conclusion --- p.38
Bibliography --- p.39
Chapter A --- Proof of Surface Normal Projecting to Gradient of Cast Shadow Boundary --- p.43
Liu, Jen-Jui, and 劉人瑞. "An Image Processing Tool by Integrating Photometric Calibration with Adaptive Image Halftoning for Electrophoretic Displays." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/94526502808257026997.
Full text國立臺灣師範大學
應用電子科技學系
98
The electrophoretic display (EPD) has become the main solution to electronic papers, but there are several limitations when it is being driven. First of all, the optical response curve of the EPD is nonlinear and temperature sensitive. In addition, the number of gray levels that can be displayed is also quite limited. The image quality is unsatisfactory if the images shown on the panel are not preprocessed to increase the number of visual gray levels and compensate the characteristics of the EPD. In this paper, we present an integrated image tool to automatically estimate the reflectance function curves under different ambient temperatures, perform adaptive image halftoning to improve visual quality, and calibrate the image to compensate the nonlinear response of EPD. The proposed approach has been verified on practical EPD panels and promising results have been achieved.
"Generalized surface geometry estimation in photometric stereo and two-view stereo matching." 2011. http://library.cuhk.edu.hk/record=b5894611.
Full textThesis (M.Phil.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (p. 58-63).
Abstracts in English and Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Generalized Photometric Stereo --- p.6
Chapter 2.1 --- Problem Description --- p.6
Chapter 2.2 --- Related Work --- p.9
Chapter 2.3 --- Photometric Stereo with Environment Lighting --- p.11
Chapter 2.4 --- Estimating Surface Normals --- p.13
Chapter 2.4.1 --- Surface Normal and Albedo Estimation --- p.14
Chapter 2.5 --- Data Acquisition Configuration --- p.17
Chapter 2.6 --- Issues --- p.19
Chapter 2.7 --- Outlier Removal --- p.22
Chapter 2.8 --- Experimental Results --- p.23
Chapter 3 --- Generalized Stereo Matching --- p.30
Chapter 3.1 --- Problem Description --- p.30
Chapter 3.2 --- Related Work --- p.32
Chapter 3.3 --- Our Approach --- p.33
Chapter 3.3.1 --- Notations and Problem Introduction --- p.33
Chapter 3.3.2 --- Depth and Motion Initialization --- p.35
Chapter 3.3.3 --- Volume-based Structure Prior --- p.38
Chapter 3.3.4 --- Objective Function with Volume-based Priors --- p.43
Chapter 3.3.5 --- Numerical Solution --- p.46
Chapter 3.4 --- Results --- p.48
Chapter 4 --- Conclusion --- p.56
Bibliography --- p.57
Lin, Tse-Hsin, and 林哲欣. "Integrating Photometric Image and LiDAR Data for Monitoring Forest Gap Dynamics in Nanjenshan Area." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48395762275478507936.
Full text國立屏東科技大學
森林系所
102
Forest gaps are from in the forest canopy when one or a few canopy tree die or is injured in a forest. The small opening or holes would become a kind of succession area filled with other trees in process forest gap regeneration or gap dynamics.The gap dynamics is a natural phenomenon of forest successions which affects the species composition, stand structure and regeneration in forest ecosystems. The purposes of this study are to discuss the forest gap dynamics in Nanjenshan via high resolution images and integrated laser scanning systems. First of all, we mapped the gap distribution in each habitat with multi-temporal aerial photos to understanding the change of gap dynamics in different habitats. Secondly, we modeled the processes of gap dynamics in each habitat and mapped spatial distribution of gaps. We further compared the rate of gap canopy closure with vertical structure in every single habitat. This study analyses three-temporal (2003, 2007, 2009 years) to understanding the change of gap rate, results showed the highest gap rate was 0.92% in 2009 years, secondly was 0.66% in 2003 year, and the lowest gap rate was 2007 years (0.51%). Gap dynamics was a notable change in canopy structure from closed to more open, and 2007~2009 years gap formation rate was higher than 2003~2007 years. This area displays the frequent interference by the Typhoon and the fairly fast conversion rate of forest. According to the classification criteria of topographic to divided into four different habitats (wind-stress, windward, leeward and valley) to explore the gap spatial in difference habitat. Results showed gap size rate of wind-stress and valley was higher than other habitats. Therefore speculate that wind-stress and valley often affected by northeast monsoon. Furthermore, this study combined with aerial photos and three-dimensional airborne laser scanning data to observate the gap vertical structure, and mapped width and depth of gap. There was a positive relationship between width and depth of gap, which means that gaps may range in area from the openings created by the death of a large tree.
Lovos, Flavia Virginia. "Estudio de variabilidad fotométrica en estrellas de tipo T Tauri." Doctoral thesis, 2019. http://hdl.handle.net/11086/14315.
Full textLas estrellas jóvenes de tipo T Tauri tienen la edad adecuada para el inicio del proceso de formación planetaria de acuerdo a los modelos más aceptados en la actualidad. Sin embargo éstas presentan algunos desafíos para la técnica clásica de detección de planetas extrasolares mediante tránsitos planetarios. Principalmente las T Tauri manifiestan diversas formas de variabilidad que, mayormente, se evidencian en sus curvas de luz. En este trabajo se presenta un análisis y caracterización de la variabilidad fotométrica de 52 estrellas T Tauri australes, a partir de datos propios obtenidos desde el CASLEO y de la EABA, como primer paso para comprender cómo esta variabilidad puede influir en la detectabilidad de potenciales embriones planetarios transitantes. Entre los tipos de variabilidad observados, el más frecuente se debe a la presencia de manchas sobre la superficie estelar, así como otros relacionados con procesos de acreción y/o obscurecimiento por polvo en discos circunestelares.
Young pre-main sequence stars of T Tauri type have appropriate ages for the beginning of the planetary formation process according to the currently most accepted models. However, T Tauri stars offer some challenges for the classical techniques of extrasolar planets detection by means of planetary transits. Principally, T Tauri stars have different types of variability that are mostly evident in their light curves. In this work is presented an analysis and characterization of the photometric variability of 52 southern T Tauri stars, from data obtained from the CASLEO and the EABA observatories, as a first step to learn how such variability may affect the detectability of transiting planetary embryos. Among the types of variabilities, the most frequent are due to the presence of spots on the stellar surfaces, as well as others related to processes of accretion and/or darkening by dust in the circumstellar disks.
Lovos, Flavia Virginia. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.
Demitri, Nevine. "Signal and Image Processing Techniques for Image-Based Photometry With Application to Diabetes Care." Phd thesis, 2016. https://tuprints.ulb.tu-darmstadt.de/5564/7/kt_thesis.pdf.
Full textAckermann, Jens. "Photometric Reconstruction from Images: New Scenarios and Approaches for Uncontrolled Input Data." Phd thesis, 2014. http://tuprints.ulb.tu-darmstadt.de/4060/7/tuprints_nocv_dissertation_ackermann_highres.pdf.
Full textBaravalle, Laura Daniela. "Objetos extensos en el relevamiento vvv (vista variables in the Vía Lactea)." Doctoral thesis, 2018. http://hdl.handle.net/11086/8892.
Full textPereira, Cedric Pedroso. "A Virtual Observatory methodology to identify and characterize asteroids in wide-field images." Master's thesis, 2019. http://hdl.handle.net/10316/86550.
Full textO desenvolvimento da tecnologia e da ciência tem permitido conhecer melhor o nosso sistema solar e de que forma a caracterização de asteróides é importante para a evolução científica e para assegurar a sobrevivência da nossa espécie. Esta dissertação de mestrado apresenta o desenvolvimento de uma metodologia de análise e processamento de imagens de grande campo, obtidas em um observatório terrestre, para identificação e caracterização de asteróides conhecidos. Este trabalho tem como base o uso de ferramentas Observatório Virtual, de acesso livre e que poderão ser utilizadas por qualquer utilizador. De modo a automatizar todo o processo serão utilizados e adaptados alguns scripts anteriormente desenvolvidos pelo grupo científico e adicionados novos scripts complementares. Dos dados fornecidos serão calculados os centróides das fontes de luz correspondentes a objectos estáticos (como no caso das estrelas) e correspondentes a objectivos que apresentam movimento (como no caso dos asteróides) e serão realizadas calibrações astrométricas com o objectivo de obter as coordenadas celestes (ascensão recta e declinação) para cada uma das fontes. Também serão realizadas calibrações fotométricas de modo a obter as magnitudes aparentes de cada fonte, para posteriormente obter as magnitudes absolutas de cada posição dos asteróides e para extrair as suas curvas de luz. Se a quantidade e qualidade dos dados permitir serão ainda calculados os seus períodos. Após analise dos dados fornecidos, os resultados serão submetidos para a base de dados Minor Planet Center, onde poderão ser aprovados para a calibração das orbitas dos asteróides em estudo.
The development of technology and science allowed us to know more about our solar system and how the characterization of asteroids is important for scientific evolution and to ensure the survival of our species. This dissertation presents the development of a methodology to analyze and process large field images, obtained by a ground-based observatory, to identify and characterize known asteroids. This work is based on use of Virtual Observatory tools, of free access and which can be used by any user. In order to automate the whole process, some scripts previously developed by the scientific group will be used along with newly-added complementary scripts. From the astronomical data, the centroids of light sources of non-moving objects (for example stars, bad pixels, etc.) and moving objects (for example asteroids) will be calculated and astrometric calibrations will be performed in order to obtain the celestial coordinates (right ascension and declination) for each light source. Photometric calibrations will be performed in order to obtain the apparent magnitude of each source, to obtain the absolute magnitude of each asteroid position and to extract their light curves. If the quantity and quality of the data allows us, their periods will be calculated using a well-known periodogram tool. After analyzing the provided data, the results will be submitted to the Minor Planet Center of the International Astronomical Union, where they can be approved for calibration of the orbits of the asteroids under study.
Bean, Keri Marie. "Determining Nighttime Atmospheric Optical Depth Using Mars Exploration Rover Images." Thesis, 2013. http://hdl.handle.net/1969.1/151097.
Full textNicklas, Harald. "The Focal Reducing Imager and Spectrograph FORS, built for the optical 16-metre ‘Very Large Telescope’ of the European Southern Observatory." Doctoral thesis, 2005. http://hdl.handle.net/11858/00-1735-0000-0006-B581-9.
Full textObara, Łukasz. "Poszukiwanie gwiazd zmiennych w eksperymencie Pi of the Sky." Doctoral thesis, 2018. https://depotuw.ceon.pl/handle/item/2706.
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