This dissertation provides a robust radiometric calibration for the TRMM Microwave Imager to correct systematic brightness temperature errors, which vary dynamically with orbit position (time) and day of the year. The presence of a time-varying bias in TMI is confirmed by inter-calibration with WindSat and SSMI. This time varying bias is manifested as a time of day dependent variation of the relative biases between TMI and both WindSat and SSMI. In this dissertation, we provide convincing evidence that this time-varying Tb bias in TMI is caused by variations in the physical temperature of the emissive TMI reflector antenna. This dissertation provides an empirical correction that largely corrects this time-varying bias. The TMI bias is estimated by comparing the 10.7 GHz V-polarization channel observations with RTM Tb predictions, and the Tb correction is applied as a function of orbit time for every day of the one year period. Furthermore, this dissertation provides a qualitative physical basis for the estimated Tb bias patterns and provides conclusive evidence that the empirical correction applied to TMI Tb measurements (both ocean and land) largely corrects the time-varying TMI calibration. This is accomplished by demonstrating that the local time-of-day dependence (in the uncorrected TMI Tb values) is removed in the corrected TMI Tb's.

L'utilisation de collections d'images pour les applications de vision par ordinateur devient de plus en plus commune des nos jours. L'objectif principal de cette thèse est d'exploiter et d'extraire des informations importantes d'images de scènes d'extérieur a partir de ce type de collections : l'illumination présente au moment de la prise, les propriétés de reflectance des matériaux composant les objets dans la scène et les propriétés radiométriques des appareils photo utilisés. Pour atteindre notre objectif, cette thèse est composée de deux parties principales. Dans un premier temps nous allons réaliser une analyse de différentes représentations du ciel et une comparaison des images basée sur l'apparence de celui-ci. Une grande partie de l'information visuelle perçue dans les images d'extérieures est due a l'illumination en provenance du ciel. Ce facteur est représenté par les rayons du soleil réfléchis et réfractés dans l'atmosphère en créant une illumination globale de l'environnement. En même temps cet environnement détermine la façon de percevoir les objets du monde réel. Etant donné l'importance du ciel comme source d'illumination, nous formulons un processus générique en trois temps, segmentation, modélisation et comparaison des pixels du ciel, pour trouver des images similaires en se basant sur leurs apparences. Différentes méthodes sont adoptées dans les phases de modélisation et de comparaison. La performance des algorithmes est validée en trouvant des images similaires dans de grandes collections de photos. La deuxième partie de cette thèse consiste a exploiter l'information géométrique additionnelle pour en déduire les caractéristiques photométriques de la scène. A partir d'une structure 3D récupérée en utilisant des méthodes disponibles, nous analysons le processus de formation de l'image a partir de modèles simples, puis nous estimons les paramètres qui les régissent. Les collections de photos sont généralement capturées par différents appareils photos, d'où l'importance d'insister sur leur calibrage radiométrique. Notre formulation estime cet étalonnage pour tous les appareils photos en même temps, en utilisant une connaissance a priori sur l'espace des fonctions de réponse des caméras possibles. Nous proposons ensuite, un cadre d'estimation conjoint pour calculer une représentation de l'illumination globale dans chaque image, l'albedo de la surface qui compose la structure 3D et le calibrage radiométrique pour tous les appareils photos. / The 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.

This study had as objective to show the importance of the spectral characteristics obtained by the physical properties of clouds measured by the METEOSAT geostationary satellite that helps on the understanding and prediction of severe storms. The study area was Brazil s southeastern because this region is located in a transition range between the mid-latitude temperate climate and the low latitudes warm climate and, therefore, becomes an area that has influence of various meteorological phenomena. With the strong topography and the proximity to the Atlantic Ocean, is a severe storms, strong winds and continuous rainfall favorable zone. It were used MSg datanot only by the images been captured from 15 in 15 minutes, but also because the SEVIRI radiometer on board of the European satellite has 12 multispectral channels that generate twenty times more information than the previous generation radiometers of the same. Were generated qualitative information of the atmospheric events in RGB color compositions, spectral response analysis and differences in the water vapor multispectral channels. The obtained results indicated that the RGB color composition (WV6.2μm - WV7.3μm; IR3.9μm - IR10.8μm; NIR1.6μm - VIS0.6μm) characterizes in a satisfactory way the convection in thunderstorms, showing when the system is in dissipation, stabilization or increasing, but is indicated only for storms occurring during the day and when analyzed the 3 RGB compositions (standard for air mass and convection) generate more information than analyzing only 1 of them. For the first case study, the values of the channel difference of the water vapor that were indicated as critical values with a trend to storm formation were of 4 to 13 ºC and for the second study case were of 8 to 13 °C. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho teve por objetivo mostrar a importância que as características espectrais obtidas por meio das propriedades físicas das nuvens medidas pelos satélites geoestacionários METEOSAT que auxilia a previsão e compreensão de tempestades severas. A região de estudo foi o sudeste brasileiro por essa região encontrar-se em uma faixa de transição entre o clima temperado das latitudes médias e o clima quente das latitudes baixas e, por isso, se torna uma área que tem influência de vários fenômenos meteorológicos. Com a topografia acentuada e a proximidade com o Oceano Atlântico, é uma zona propicia a tempestades severas, vendavais e chuvas contínuas. Foram utilizados os dados do MSG não apenas pelas imagens serem captadas de 15 em 15 minutos, mas também, porque o radiômetro SEVIRI a bordo desse satélite europeu possui 12 canais multiespectrais que geram vinte vezes mais informações do que os radiômetros da geração anterior do mesmo. Foram geradas informações qualitativas dos eventos atmosféricos nas composições coloridas RGB, análise da resposta espectral e diferenças dos canais multiespectrais de vapor de água. Os resultados obtidos indicaram que a composição colorida RGB (WV6.2µm WV7.3µm; IR3.9µm IR10.8µm; NIR1.6µm VIS0.6µm) caracteriza de maneira satisfatória a convecção em tempestades, mostrando quando o sistema está-se dissipando, estabilizado ou intensificando, porém é indicada apenas para as tempestades que ocorrem durante o dia e quando analisada as 3 composições RGB (padrão, para massas de ar e convecção) geram mais informações do que analisando apenas 1 delas. Para o 1° estudo de caso os valores da diferença de canais do vapor de água que foram indicados como valores críticos propícios a formação de tempestades foram de 4 a 13°C e para o 2° estudo de caso foram de 8 a 13°C.

Submitted by ÉRIKA AKEMI SAITO MORIYA null (eakemisaito@gmail.com) on 2016-02-01T22:32:38Z No. of bitstreams: 1 tese_erikamoriya_01022016.pdf: 3211942 bytes, checksum: 65312c57be7482f001060a746a9d581f (MD5) / Approved for entry into archive by Sandra Manzano de Almeida (smanzano@marilia.unesp.br) on 2016-02-02T12:45:37Z (GMT) No. of bitstreams: 1 moriya_eas_dr_prud.pdf: 3211942 bytes, checksum: 65312c57be7482f001060a746a9d581f (MD5) / Made available in DSpace on 2016-02-02T12:45:37Z (GMT). No. of bitstreams: 1 moriya_eas_dr_prud.pdf: 3211942 bytes, checksum: 65312c57be7482f001060a746a9d581f (MD5) Previous issue date: 2015-12-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A hipótese levantada neste trabalho foi que as imagens hiperespectrais tomadas de plataformas aéreas como o veículo aéreo não-tripulado (VANT) e assinaturas espectrais medidas em campo ou laboratório podem ser utilizados em Agricultura de Precisão, especificamente na identificação de doenças na lavoura de cana-de-açúcar. Para testar esta hipótese foi delineado um objetivo principal, desenvolver uma metodologia para realizar o tratamento e análise de imagens hiperespectrais obtidas por sensor aerotransportado, de modo que os produtos auxiliem na caracterização da resposta espectral da cana-de-açúcar visando a discriminação e reconhecimento de talhões com doença na cana-de-açúcar. Portanto, neste trabalho desenvolveu-se uma metodologia que envolveu a realização de levantamentos em campo apoiados radiometricamente e a realização de análises em laboratório, para obter a curva espectral de cana-de-açúcar sadia e doentes, no intuito de identificar os comprimentos de onda mais propícios para detecção de doenças. A identificação de comprimentos de onda sensíveis a mudanças pela ação de agentes patogênicos foi importante para a elaboração de índices para detecção de duas doenças da cana-de-açúcar (estria vermelha e mosaico). Além disso, foi analisada a influência do ângulo de visada na estimativa do fator de reflectância hemisférico cônico na cana-de-açúcar, verificando o efeito da anisotropia na cana-de-açúcar. A obtenção de informação sobre o efeito da anisotropia na cana-de-açúcar foi importante para definir a estratégia de processamento das imagens hiperespectrais. As regiões com cana-de-açúcar infectadas com estria vermelha e mosaico foram discriminadas a partir de imagens hiperespectrais adquiridas por VANT, proporcionando informação para o planejamento da aplicação de defensivos agrícolas com a determinação precisa do posicionamento das regiões contaminadas e definição das estratégias de manejo da cultura agrícola visando um melhor gerenciamento da produção. / The hypothesis in this study was that the hyperspectral images taken from aerial platforms like unmanned aerial vehicle (UAV) and spectral signatures measured in field or lab can be use in precision agriculture, specifically in identifying diseases in sugarcane crop. To test this hypothesis has been outlined a primary objective to develop a methodology to perform processing and analyzing hyperspectral images obtained by airborne sensor, so that the products assist in characterizing the spectral response of the sugarcane aiming discrimination and recognition stands with disease in sugarcane. Therefore, this study developed a methodology that involved surveying in supported radiometrically field and the analysis in the laboratory for the spectral curve of healthy and diseased sugarcane in order to identify the most propitious wavelengths to detect diseases. The identification of wavelengths sensitive to changes by the action of pathogens was important for the development of indexes to detect two diseases of sugarcane (red stripe and mosaic). Furthermore, was analyzed the influence of the viewing angle in estimating the hemispherical conical reflectance factor in sugarcane, by checking the effect of anisotropy in sugarcane. Obtaining information on the effect of anisotropy on sugarcane was important to define the hyperspectral image processing strategy. Regions with sugarcane infected with red stripe and mosaic were discriminated from hyperspectral images acquired by UAV, providing information for planning the application of agriculture defensives with the precise determination of the positioning of the contaminated regions and defining the management strategies of the crop to provide a better production management.

La mission BepiColombo est une des pierres angulaires du programme scientifique de l'ESA. Elle permettra l'étude de la planète Mercure grâce à deux sondes mises en orbite autour de la planète. Une des deux sondes, Mercury Planetary Orbiter (MPO) développée par l'ESA, sera dédiée à l'étude de la surface et de l'intérieur de la planète. La mission est prévue pour un lancement en 2016 et une arrivée sur Mercure en janvier 2024. L’IAS est responsable de l’étalonnage de l'ensemble d'imageurs SIMBIO-SYS (Spectrometer and Imagers for MPO BepiColombo-Integrated Observatory SYStem) composé d’une caméra haute résolution (HRIC), d’une caméra stéréoscopique (STC) et d’un imageur hyperspectral visible et proche-infrarouge (VIHI). Ces instruments devraient profondément modifier nos connaissances de la composition et de la géomorphologie de la surface de Mercure. Ma thèse a consisté à participer à la définition et à la mise en place des caractéristiques et des fonctionnalités du dispositif expérimental d'étalonnage qui se compose principalement d’une cuve à vide contenant les instruments, d’un banc optique rassemblant les sources d'étalonnage et les éléments optiques qui reconstituent les conditions d'observation de Mercure, des interfaces mécaniques permettant le positionnement de l'expérience à l'intérieur de la cuve, des interfaces thermiques visant à explorer les températures de fonctionnement des différentes parties des expériences, des interfaces informatiques assurant la communication avec l'expérience et le pilotage du dispositif d'étalonnage en fonction des tests à réaliser. J’ai modélisés et validé expérimentalement certaines performances du dispositif. Enfin, j’ai défini en étroite collaboration avec les équipes italiennes co-responsables des trois instruments les différentes séquences d’étalonnage qui seront utilisées lors de l’étalonnage. / BepiColombo is one of the cornerstones of the scientific program of ESA. It will study the planet Mercury with two spacecrafts in orbit around the planet. One of the two spacecrafts, the Mercury Planetary Orbiter (MPO), will be dedicated to the study of the surface and interior of the planet. The mission is scheduled for launch in 2016 and arrival at Mercury in January 2024. IAS is responsible for the calibration of the imaging system SIMBIO-SYS (Spectrometers and Imagers for MPO BepiColombo Integrated Observatory-SYStem) which consists of a high-resolution camera (HRIC), a stereoscopic camera (STC) and a visible and near-infrared hyperspectral imager (VIHI). These instruments should deeply change our understanding of the composition and geomorphology of Mercury surface. My research subject allowed me to participate in all the activities concerning the definition, implementation and validation of the calibration facilities at the IAS. These facilities are divided into different sub-systems: a thermal vacuum chamber containing the instrument during all the calibration campaign that shall simulate the environmental conditions (temperature and pressure), an optical bench with optical components and radiometrically calibrated sources reproducing the observational conditions as it will be seen by the instrument once placed in Mercury’s orbit, mechanical interfaces allowing the positioning and guidance of the instrument when placed inside the vacuum chamber with the required precision and accuracy, thermal interfaces facilitating the thermal excursion of the detectors, software interfaces so as to automatize and control the entire system. I developed a radiometric model of the calibration system and instrument to refine the calibration sources. In parallel, I performed several measurements of some subsystems so as to validate the optical assembly and to improve its control. Finally as a result of a close collaboration with the three Italian scientific teams of the instrument, I elaborate the fully package of the calibration sequences and the detailed instrument configuration that will be used during the calibration campaign.