Stora arealer skog behöver övervakas. Att göra detta på ett kostnadseffektivt sätt är något som skogssektorn efterfrågar. Syftet med studien var att undersöka möjligheten att skatta skogliga variabler med satellitbilder från Sentinel 2. Korrelationen mellan granskogens uppmätta reflektans i satellitbilder från Sentinel 2 och uppmätta variablerna i fält har beräknats och analyserats. Resultatet visar att styrkan i korrelation skiljer sig mellan olika rumsliga upplösningar, vilken tid på året satellitbilderna är tagna, vilka spektrala band och vegetationsindex som används samt vilka skogliga variabler som avses uppskattas. Att använda enskilda satellitbilders värden från Sentinel 2 ger inte tillräckligt tillförlitliga data för att uppskatta skogliga variabler.

Conifers are important both ecologically and socioeconomically, however, same parts of their biology are not that well researched. This includes genetics and breeding and partly even physiology. Because quantitative genetic analyzes applied in breeding necessitate an analysis of a large number of samples, and conventional methods of analysis are quite time-consuming, certain parameters describing e.g. the activity of photosynthetic electron-transport chain (ETC) are considered for such use. Several methods of the measurement of the activity of photosynthetic ETC exist, but there are some problems with their usage in conifers. I studied this issue from different points of view in three parts of this thesis. 1) I compared the photosynthetic ETC activity in 8 species of conifers using chlorophyll (Chl) fluorescence measurements on intact needles and polarographic measurements in isolated chloroplasts. Each method brought different information. 2) I measured Chl fluorescence parameters, reflectance spectra and pigment content in 536 genetically defined trees of Pinus sylvestris L. Many parameters showed relatively high genetic variability and heritability. I have also determined the suitability of various reflectance indices to estimate pigment and water content of needles. 3) I have optimized the...

Thermography is a non-destructive technique which uses infrared radiation to obtain the temperature distribution of an object. The technique is increasingly used in the pulp and paper industry. To convert the detected infrared radiation to a temperature, the emittance of the material must be known. For several influencing parameters the emittance of paper and board has not previously been studied in detail. This is partly due to the lack of emittance measurement methods that allow for studying the influence of these parameters. An angle-resolved goniometric method for measuring the infrared emittance of a material was developed in this thesis. The method is based on the reference emitter methodology, and uses commercial infrared cameras to determine the emittance. The method was applied to study the dependence on wavelength range, temperature, observation angle, moisture ratio, sample composition, and sample structure of the emittance of paper and board samples. It was found that the emittance varied significantly with wavelength range, observation angle and moisture ratio. The emittance was significantly higher in the LWIR (Long-Wavelength Infrared) range than in the MWIR (Mid-Wavelength Infrared) range. The emittance was approximately constant up to an observation angle of 60° in the MWIR range and 70° in the LWIR range, respectively. After that it started to decrease. The emittance of moist samples was significantly higher than that of dry samples. The influence of moisture ratio on the emittance could be estimated based on the moisture ratio of the sample, and the emittance of pure water and dry material, respectively. The applicability of measured emittance values was demonstrated in an investigation of the mechanical properties of sack paper samples. An infrared camera was applied to monitor the generation of heat during a tensile test of a paper sample. It was found that the observed increase in thermal energy at the time of rupture corresponded well to the value of the elastic energy stored in the sample just prior to rupture. The measured emittance value provided an increased accuracy in the thermal energy calculation based on the infrared images. / <p>QC 20121121</p>

Hyperspectral imaging has become one of the most popular technologies in plant phenotyping because it can efficiently and accurately predict numerous plant physiological features such as plant biomass, leaf moisture content, and chlorophyll content. Various hyperspectral imaging systems have been deployed in both greenhouse and field phenotyping activities. However, the hyperspectral imaging quality is severely affected by the continuously changing environmental conditions such as cloud cover, temperature and wind speed that induce noise in plant spectral data. Eliminating these environmental effects to improve imaging quality is critically important. In this thesis, two approaches were taken to address the imaging noise issue in greenhouse and field separately. First, a computational simulation model was built to simulate the greenhouse microclimate changes (such as the temperature and radiation distributions) through a 24-hour cycle in a research greenhouse. The simulated results were used to optimize the movement of an automated conveyor in the greenhouse: the plants were shuffled with the conveyor system with optimized frequency and distance to provide uniform growing conditions such as temperature and lighting intensity for each individual plant. The results showed the variance of the plants’ phenotyping feature measurements decreased significantly (i.e., by up to 83% in plant canopy size) in this conveyor greenhouse. Secondly, the environmental effects (i.e., sun radiation) on <a>aerial </a>hyperspectral images in field plant phenotyping were investigated and modeled. <a>An artificial neural network (ANN) method was proposed to model the relationship between the image variation and environmental changes. Before the 2019 field test, a gantry system was designed and constructed to repeatedly collect time-series hyperspectral images with 2.5 minutes intervals of the corn plants under varying environmental conditions, which included sun radiation, solar zenith angle, diurnal time, humidity, temperature and wind speed. Over 8,000 hyperspectral images of </a>corn (<i>Zea mays </i>L.) were collected with synchronized environmental data throughout the 2019 growing season. The models trained with the proposed ANN method were able to accurately predict the variations in imaging results (i.e., 82.3% for NDVI) caused by the changing environments. Thus, the ANN method can be used by remote sensing professionals to adjust or correct raw imaging data for changing environments to improve plant characterization.

Les satellites glacés de Jupiter sont d'un grand intérêt scientifique dans la recherche d'habitabilité au sein de notre système solaire. Elles abritent probablement toutes trois des océans d'eau liquide sous leur croûte glacée. Leurs surfaces présentent différents stades d’évolution – celle de Callisto est très ancienne et entièrement recouverte de cratères, celle de Ganymede est un mélange de terrains sombres et cratérisés et de plaines claires et plus jeunes et la surface d’Europa est la plus jeune et présente des signes d’activité récente. Cette thèse porte sur la photométrie, c’est à dire l’étude de l’énergie lumineuse réfléchie par une surface, en fonction des géométries d’éclairement et d’observation. Les études photométriques permettent de déterminer l’état physique et la microtexture des surfaces (porosité, structure interne, forme des grains, rugosité, transparence…). Une bonne connaissance photométrique est également d'une importance cruciale dans la correction des jeux de données pour toute étude cartographique ou spectroscopique ainsi que pour les futures missions de cette décennie : Europa Clipper de la NASA et JUpiter ICy Moons Explorer de l’ESA.Deux types d’information sont nécessaires pour réaliser une étude photométrique : des données de réflectance et des données géométriques (conditions d’illumination et d'observation). Pour obtenir les premières, nous avons utilisé et calibré des images de missions spatiales passées - Voyager, New Horizons et Galileo. Pour obtenir les secondes, nous avons développé des outils permettant de corriger les métadonnées de ces images (ex : la position et l'orientation des sondes) afin d’obtenir des informations géométriques précises. Nous avons, d’autre part, développé un outil d’inversion pour estimer les paramètres photométriques de Hapke sur des régions d’Europa, Ganymede et Callisto sur l’ensemble du jeu de données en un seul calcul. Enfin, nous discutons des liens possibles entre les paramètres photométriques estimés, la microtexture de la surface et les processus endogènes/exogènes mis en jeu. / Jupiter'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.

La conduction thermique devient moins efficace à mesure que la taille des struc-tures diminuent en desous du micron, car la diffusion de surface des phononsdevient prédominante et limite plus efficacement les phonons que la diffusionphonon-phonon Umklapp. Des études récentes ont indiqué que les phonon po-laritons de surface (SPhPs), qui sont les ondes électromagnétiques évanescentesgénérées par l’hybridation des phonons optiques et des photons et se propageantà la surface d’une surface diélectrique polaire, pourraient servir de nouveauxvecteurs de chaleur pour améliorer les performances thermiques dans des dis-positifs micro- et nano-métriques. Nous étudions l’état des SPhPs existantdans un film submicronique diélectrique dans une large gamme de fréquences.Le calcul de la conductivité thermique des SPhPs basé sur l’équation de trans-port de Boltzmann (BTE) montre que le flux de chaleur transporté par lesSPhPs est supérieur à celui des phonons. Nous effectuons également une mesurede réflectance thermique dans le domaine temporel (TDTR) de films submi-croniques deSiNet démontrons que la conductivité thermique due aux SPhPsà haute température augmente lorsque l’épaisseur du film dimine. Les résultatsprésentés dans cette thèse ont des applications potentielles dans le domaine dutransfert de chaleur, de la gestion thermique, du rayonnement en champ proche et de la polaritoniques. / Thermal conduction becomes less efficient as structures scale down into submicron sizes since phonon-boundary scattering becomes predominant and impede phonons more efficiently than Umklapp scattering. Recent studies indicated that the surface phonon polaritons (SPhPs), which are the evanescent electromagnetic waves generated by the hybridation of the optical phonons and the photons and propagating at the surface of a polar dielectric material surface, potentially serve as novel heat carriers to enhance the thermal performance in micro- and nanoscale devices. We study the condition of SPhPs existing in a dielectric submicron film with a broad frequency range. The calculaton of SPhPs thermal conductivity based on Boltzmann transport equation (BTE) demonstrates that the heat flux carried by SPhPs exceeds the one carried by phonons. We also conduct a time-domain-thermal-reflectance (TDTR) measurement of $SiN$ submicron films and demonstrate that the thermal conductivity due to the SPhPs at high temperatures increases by decreasing the film thickness. The results presented in this thesis have potential applications in the field of heat transfer, thermal management, near-field radiation and polaritonics.

In der vorliegenden Arbeit werden die optischen Eigenschaften von dünnen PTCDA und TiOPc Schichten untersucht. Dies wurde mit der Kombination der Methoden der Molekularstrahlepitaxie (OMBE), der differentiellen Reflexionsspektroskopie (DRS) und Photolumineszenzmessungen möglich. Dabei steht der Übergang vom Einzelmolekül zum molekularen Festkörper im Mittelpunkt. Der realisierte optische Aufbau ermöglicht es, die optischen Eigenschaften von molekularen Sub- und Multilagen während der Schichtabscheidung im Ultrahochvakuum (UHV) zu bestimmen. Eine Strukturuntersuchung kann so unmittelbar darauf im UHV durchgeführt werden, ohne Umordnungsprozesse durch einen Probe-Luft-Kontakt zu riskieren. In dieser Arbeit wurden PTCDA-Schichten auf Muskovit-Glimmer(0001) und auf Au(100) untersucht. Auf Glimmer wird sehr gut ausgeprägtes Lagenwachstum gefunden, die Moleküle bilden auf dem schwach wechselwirkenden Substrat hochgeordnete epitaktische Filme. Dies ermöglichte für PTCDA, als quasi-eindimensionaler Molekülkristall, die optische Charakterisierung von Monomeren, Stapel-Dimeren und -Oligomeren während des Filmwachstums mittels DRS und Photolumineszenzmessungen. Die DRS-Messungen zeigen, daß die bekannten Festkörpereigenschaften schon bei Schichtdicken in der Größenordnung von 3-4 Gitterkonstanten ausgeprägt sind. Bis zu diesen Dicken sind die wesentlichen Änderungen in den optischen Eigenschaften zu beobachten. Ausgehend von Monomer-typischen Spektren entwickeln sich in dieser Dickenskale bereits alle Charakteristika der Festkörperspektren, wobei der Monomer-Dimerübergang die gravierendsten spektralen Änderungen hervorruft. Diese überraschende Tatsache war von den gängigen Theorien so nicht zu erwarten und ist Beleg für eine starke Wechselwirkung zwischen den dicht gepackten Molekülen. Steigen die Dimensionen des Films weiter, gibt es nur noch marginale Änderungen, die sich hauptsächlich in spektralen Verschiebungen äußern. Diese &amp;quot;finite-size&amp;quot; Effekte sind mit gängigen Theorien der Delokalisation der molekularen Anregung verträglich. Die Größe der Verschiebungen deutet jedoch darauf hin, daß gestalt- und dickenabhängige dielektrische Effekte gegenüber Delokalisierung und Confinement von Excitonen dominieren. Die veränderte Substratwechselwirkung auf der Au(100)-Oberfläche zeigt sich sowohl in verändertem Filmwachstum als auch abweichenden optischen Eigenschaften. Es wurde beobachtet, daß sich die Einflüsse durch die Substratbindung auf der Längenskala von nur einer Gitterkonstanten auswirken. Die PTCDA-Lagen, die auf dieser hybridisierten Grenzschichtlage wachsen, haben bereits die vom ungestörten System bekannten Eigenschaften. Da auf der Goldoberfläche mit zunehmender Schichtdicke das Inselwachstum (Stranski-Krastanov-Wachstum) überwiegt, verwischen die schichtabhängigen spektralen Änderungen zusehends. Für TiOPc auf Glimmer(0001) wurde bei Raumtemperatur amorphes Wachstum beobachtet, mit weniger gravierenden spektralen Änderungen. Jedoch sind auch in diesem System große dickenabhängige Verschiebungen in den Spektren festzustellen, die wie im Fall von PTCDA-Schichten hauptsächlich dielektrischen Effekten zugerechnet werden können. In TiOPc/PTCDA-Heteroschichten auf Glimmer konnte der Energietransfer vom PTCDA zum TiOPc auf molekularer Ebene, durch Löschung der PTCDA-Lumineszenz und anschließender sensibilisierter Emission des TiOPc, nachgewiesen werden. Dabei wurde bei sehr kleinen TiOPc-Schichtdicken die Emission von TiOPc-Monomeren beobachtet. Zusätzlich wurde eine dem Anion TiOPc- zuzurechnende Emission, als Indiz einer Ladungstrennung auf molekularer Ebene festgestellt. Bei größeren TiOPc-Schichtdicken tritt Exciplexemission auf, als Beleg für die starke Molekül-Molekül-Wechselwirkung an der Grenzfläche. Bei dickeren Schichten wird mit zunehmender Aggregation der TiOPc-Moleküle, die Lumineszenzausbeute durch Öffnung einer Reihe von nichtstrahlenden Rekombinationsmöglichkeiten, wie auch bei PTCDA beobachtet, geringer.

[pt] Diferentemente de muitas outras rochas, o carvão é uma rocha sedimentar composta principalmente de matéria orgânica derivada de detritos vegetais, acumulados em turfeiras em diferentes períodos geológicos. O carvão é um recurso econômico essencial em muitos países, tendo sido a principal força motriz por trás da revolução industrial. O carvão é amplamente utilizado industrialmente para diversos fins: carbonização e produção de coque, produção de ferro/aço, carvão térmico para gerar eletricidade, liquefação e gaseificação. A utilização do carvão é ditada pelas suas propriedades que são geralmente classificadas como sua composição, rank e grau. A composição do carvão, em termos dos seus macerais, e a sua classificação são determinadas manualmente por um petrógrafo, devido à sua natureza complexa. Este estudo almejou desenvolver um método automático baseado na aprendizagem de máquina para segmentação automática de macerais a nível de grupo e um módulo para determinação de rank por refletância em imagens petrográficas do carvão que pode melhorar a eficiência deste processo e diminuir a subjetividade do operador. foi desenvolvida uma abordagem de aprendizagem profunda da arquitetura baseada na Mask R-CNN para identificar e segmentar o grupo de maceral vitrinite, o qual é fundamental para a análise do rank, uma vez que a classificação é determinada pela reflectância da collotelinite (maceral desse grupo). Em segundo lugar, foi desenvolvido um método de processamento de imagem para analisar as imagens segmentadas de vitrinite e determinar a classificação do carvão, associando os valores cinzentos à reflectância. Para a segmentação de maceral, foram utilizadas cinco amostras para treinar a rede, 174 imagens foram utilizadas para treino, e 86 foram utilizadas para validação, com os melhores resultados obtidos para os modelos de vitrinite, inertinita, liptinita e colotelinita (89,23%, 68,81%, 37,00% e 84,77% F1-score, respectivamente). Essas amostras foram utilizadas juntamente com outras oito amostras para determinar os resultados de classificação utilizando a reflectância de collotelinite. As amostras variaram entre 0,97% e 1,8% de reflectância. Este método deverá ajudar a poupar tempo e mão-de-obra para análise, se implementado num modelo de produção. O desvio médio quadrático entre o método proposto e os valores de reflectância de referência foi de 0,0978. / [en] Unlike most other rocks, coal is a sedimentary rock composed primarily of organic matter derived from plant debris that accumulated in peat mires during different geological periods. Coal is also an essential economic resource in many countries, having been the main driving force behind the industrial revolution. Coal is still widely used industrially for many different purposes: carbonization and coke production, iron/steel making, thermal coal to generate electricity, liquefaction, and gasification. The utility of the coal is dictated by its properties which are commonly referred to as its rank, type, and grade. Coal composition, in terms of its macerals, and its rank determination are determined manually by a petrographer due to its complex nature. This study aimed to develop an automatic method based on machine learning capable of maceral segmentation at group level followed by a module for rank reflectance determination on petrographic images of coal that can improve the efficiency of this process and decrease operator subjectivity. Firstly, a Mask R-CNN-based architecture deep learning approach was developed to identify and segment the vitrinite maceral group, which is fundamental for rank analysis, as rank is determined by collotelinite reflectance (one of its individual macerals). Secondly, an image processing method was developed to analyze the vitrinite segmented images and determine coal rank by associating the grey values with the reflectance. For the maceral (group) segmentation, five samples were used to train the network, 174 images were used for training, and 86 were used for testing, with the best results obtained for the vitrinite, inertinite, liptinite, and collotelinite models (89.23%, 68.81%, 37.00% and 84.77% F1-score, respectively). Those samples were used alongside another eight samples to determine the rank results utilizing collotelinite reflectance. The samples ranged from 0.97% to 1.8% reflectance. This method should help save time and labor for analysis if implemented into a production model. The root mean square calculated between the proposed method and the reference reflectance values was 0.0978.

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