Dissertations / Theses on the topic 'Visible and near-infrared range'
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Cone, Shelli R. "Exploration of integrated visible to near-, shortwave-, and longwave-infrared (full-range) spectral analysis." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43893.
Full textVisible to near-, shortwave-, and longwave-infrared (VNIR, SWIR, LWIR) remote sensing data are typically analyzed in their individual wavelength regions, even though theory suggests combined use would emphasize complementary features. This research explored the potential for improvements in material classification using integrated datasets. Hyperspectral (HSI) VNIR and SWIR data from the MaRSuper Sensor System (MSS-1) were analyzed with HSI LWIR data from the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) to determine differences between individual (baseline) and combined analyses. The first integration approach applied separate minimum noise fraction (MNF) transforms to the three regions and combined only non-noise transformed bands from the individual regions during analysis. The second approach integrated over 470 hyperspectral bands covering the VNIR, SWIR, and LWIR wavelengths before using MNF analysis to isolate linear band combinations containing high signal to noise. Spectral endmembers isolated from data were unmixed using partial unmixing. The feasible and high abundance pixels were spatially mapped using a consistent feasibility ratio threshold. Both integration methods enabled straight-forward and effective identification, characterization, and mapping of the scene because higher variability existed between endmembers and background. Results were compared to the baseline analysis. Material identification was more conclusive when analyzing across the full spectrum.
Zalavadia, Ajaykumar. "A Broadly Tunable Surface Plasmon-Coupled Wavelength Filter for Visible and Near Infrared Hyperspectral Imaging." Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1522253688346498.
Full textSeger, Kai. "Compact solid-state lasers in the near-infrard and visible spectral range." Doctoral thesis, KTH, Laserfysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121976.
Full textQC 20130507
Ullah, Anayat [Verfasser]. "Optimization of the Mechanical and Optical Properties of Tunable Optical Sensor Arrays (TOSA) for a Nanospectrometer in the Visible and Near Infrared Spectral Range / Anayat Ullah." Kassel : Universitätsbibliothek Kassel, 2014. http://d-nb.info/1065080360/34.
Full textOgudo, Kingsley. "Development of edge-emitting Si/SiGe based optical sources operating in the visible and near visible range wavelength for sensing and communication applications." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1060/document.
Full textWe propose a low cost full-silicon optical links utilizing 650 – 850 nm propagation wavelengths. The creation of large-scale opto-electronic integrated circuits and optical data “highways” inCMOS integrated circuitry, utilizing Si CMOS compounds, have been envisioned and hold much promise [1] - [3] The latest attempts for realizing optoelectronic systems in CMOS technology have until now mainly been focused on utilizing wavelengths at 1550 nm [4] - [6], mainly because of the ease of design and fabrication of waveguides in this wavelength regime. However, no effective high-speed optical sources and Si detectors are available at this 1550nmwavelength. Today solutions to overcome the problem are mostly focused on the integration of group III-V elements based optical sources on Silicon through molecular bonding [7a] – [7b]. If optical sources, detectors, waveguides, and sensors could be realized on the same Si CMOS chip at, say, 750 nm wavelength, various low power consuming, light and miniature on-chip-based micro-photonic systems can be designed and realized. While Silicon optical sources may not yet be at the required performance level for very-high speed communications, the low cost “all silicon”opto-electronic systems still remain a great grail. These sources could lead as well to new field that could be appropriately named “Si photonic microsystems” opening the route to new sensing applications and products especially for the medical, biomedical optics, optical interconnect and bio-photonics field. These systems also do not require ultrahigh frequency bandwidths to transmit, and the emission powers of our avalanche Si light-emitting diodes(LEDs) may be sufficient to sustain the operation of such systems. This PhD thus deals with low cost SiGe/Si optical links using Microwave-Photonics devices such as, Bipolar integrated SiAvLED, Silicon Nitride and Silicon Oxide optical waveguides, SiGeHPTs, Si and SiGe/Si LEDs. It focuses on the combined integration of micron-scale optical sources, optical waveguides and detectors on the same chip to form a complete communication link for various applications involving short wavelength links (750nm to 950nm). The progress provided by this PhD to previous works could be synthesized as below:• Optical source, waveguide and the detector were all integrated and aligned on the same chip, in an industrial based technology, to form complete on-chip micro-optical links at750nm wavelength, with a SiGe radio frequency (RF) 0.35µm bipolar process.• A series of second generation of on-chip optical communication links of 50µm length, utilizing 650 – 850 nm propagation wavelengths, have been designed and realized inSiGe. Micron dimensioned optical sources, waveguides and detectors were all integrated ion the same chip to form a complete communication on-chip micro-optical links. Avalanche based Si LEDs (Si Av LEDs), Schottky contacting, TEOS densification strategies, Silicon-Nitride based waveguides, and state of the art SiGe bipolar detector technologies were used as key design strategies.• R-soft simulation software (Beam Prop) was used as a mathematical capable simulation tool to model various Silicon-Nitride optical waveguide structures, before the designing, the fabrication, characterization and testing of the device. Various device structures were modeled, simulation iterations were performed on several optical waveguide designed structures before the device design, and the devices were tested experimentally.• Best performances of the designed on-chip optical links show a conversion loss as low as30dB from source to detector with up to 500MHz in cut off frequency. The good alignment and the good efficiency of each device are then clearly achieved. Higher frequency performances are also envisaged from preliminary measurements
Giorgis, Valentina. "Design, fabrication and characterization of metamaterial inspired structures for sensing application." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8576.
Full textIn the last few years the interest in nanostructures for sensing application has grown increasingly, leading to the development of new designs based on the surface plasmon resonance of metallic structures. By carefully tuning the geometry of the nanostructures, it is possible to adjust the resonance frequencies, resulting in amplification and confinement of the electromagnetic field around specific areas of the structure. The oscillating plasmonic field obtained may be exploited for bio-chemical detection. In this work we present the design, the fabrication and the characterization of gold nano split ring resonators on transparent substrate, combining finite element simulation, lithographic techniques and transmittance ellipsometry. Bearing in mind the importance of the control of the geometric parameters, we approach the structure fabrication using top-down lithographic techniques. We explore and develop, in particular, an X-ray Lithography based process for producing high volumes of tall, nanometric split ring resonators. The choice of X-ray Lithography as the main technique is justified by the possibility to obtain higher aspect ratio and to achieve large areas array of split ring resonators in a single, fast exposure, compared to other techniques, such as nanoimprinting or Electron Beam Lithography. The structure we focused our research on is the split ring resonator, one of the most popular and studied geometries for metamaterials. As metamaterial building block, the split ring resonator exhibits characteristic plasmonic resonances and a tunable frequency magnetic resonance. Besides, the split ring resonator shows a strong polarization dependance and a strong mechanical stability. In this thesis we will analyze the optical properties of the split ring nanostructure when illuminated in normal incidence. The analysis of the response in transmission at two polarization is presented. The preliminary detection test performed using a monolayer of dodecanthiol evidence the detection potential of this geometry.
XXV Ciclo
1984
Singh, Baljinder. "Visible and near-infrared spectroscopic analysis of potatoes." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84074.
Full textA further study was conducted to find the best wavelengths for predicting water content using two methods, PLS and multiple linear regression. Wavelength ranges of 910-1020, 1129-1211, 1363-1403 nm were selected for samples without skin, while 700-900, 930-1050, 1100-1300, 1400-1550 nm were selected for samples with-skin. Weight prediction models were established using the predicted water content.
Visible spectroscopy was used for classifying shriveled and non-shriveled potatoes. The wavelength ranges best suited to such a classification were those of 442-452, 456-466, 641-651, and 684-694 nm, with accuracies as high as 94.28% and as low as 80%.
Abdel-Nour, Nicolas. "Chicken egg quality assessment from visible/near infrared observations." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32396.
Full textL'oeuf est un composant fragile dans le regime alimentaire humain. Des changements importants arrivent dans loeuf pendant le stockage. La prediction de ces changements eat ctitique pour classer les oeufs selon leur qualité et leur fraîcheur. Les objectifs de cette étude étaient d'évaluer l'application méthode basée sur la spectroscopie visible et infra-rouge proche comme une method non destructive pour l'évaluation de la qualité et la fraîcheur des oeufs. Donc, la transmission visible et infra rouge proche des données spectrales aux limites de 350 à 2500 nm ont été exécutées à l'aide d'un radiosectromètre sur 360 oeufs récemment pondus. Un modèle des moindres carrées partiels (MCP) a été construit afin de lier les données soectrakes avec les méthodes destructives les plus utilisées, à savoir Unité de Haugh at le pH d'albumen en termes de qualité d'oeufs et le nombre de jours de stoclage en termees de fraîcheur d'oeufs. La première étude a traité de la capacité de la méthode maximum R2 à choisir les longueurs d'onde appropriées afin d'établir un modèle des moindres carrés partiels (MCP). Les résultats ont révélé combien cette méthode a été un bon outil dans le choix des longueurs d'onde instructives et dans l'amélioration de la capacité prédictive du modèle. Le coefficient de détermination (R2) et les erreurs de la racine carrée moyenne (ERCM) ont été calculés afin de choisir des ensembles de longueurs d'onde, lesquels aident le mieux à construire le modèle qui possède la meilleure capacité prédictive. La seconde étude a visé l'établissement des modèles prédictifs de la fraîcheur d'oeufs en fonction du n
Klesman, Alison J. (Alison June) 1981. "Comet-asteroid differentiation using visible and near-infrared spectroscopy." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28610.
Full textIncludes bibliographical references (leaves 40-42).
Comets have historically been defined as objects that experience the formation of a "head" (coma) or "tail" as ice and other volatiles that comprise their chemical makeup vaporize when they near the sun. Comets can lose this ability to form a coma or tail, however, through a variety of dynamical processes, creating objects that could chemically be comets but that do not fit the traditional definition. Thus, a new challenge has arisen to correctly define the properties that differentiate comets and asteroids. In this study, a number of cometary candidates were observed in visible and infrared wavelengths in an attempt to correctly classify them as asteroids or dormant or extinct comets. From this data, two groups of objects were identified: one group of possible cometary candidates, and one group of likely outer asteroid belt origin objects. From this and other studies, a broader picture of solar system dynamics can be achieved that will give much insight into not only the current dynamical processes that control interplanetary bodies, but also processes that were important in the formation and stratification of the solar system at its birth.
by Alison J. Klesman.
S.M.
Balkenhol, Michelle Rose. "Visible and near infrared reflectance spectroscopy of irregular solids /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/8493.
Full textHowell, Ellen Susanna. "Probing asteroid composition using visible and near-infrared spectroscopy." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187372.
Full textFont, Aragonès Xavier. "Visible, near infrared and thermal hand-based image biometric recognition." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/117685.
Full textEl Reconeixement Biomètric fa referència a la identi cació automàtica de persones fent us d'alguna característica o modalitat anatòmica (empremta digital) o d'alguna característica de comportament (signatura). És un aspecte fonamental en qualsevol procés relacionat amb la seguretat, la compartició de recursos o les transaccions electròniques entre d'altres. És converteix en un pas imprescindible abans de concedir l'autorització. Aquesta autorització, s'entén que protegeix recursos clau, permeten així, que aquests siguin utilitzats pels usuaris que han estat autoritzats a utilitzar-los o a tenir-hi accés. Els sistemes biomètrics poden funcionar en veri cació, on es resol la pregunta: Soc jo qui dic que soc? O en identi cació on es resol la qüestió: Qui soc jo? La comunitat cientí ca ha incrementat els seus esforços per millorar el rendiment dels sistemes biomètrics. En funció de l'aplicació, diverses solucions s'adrecen a treballar amb múltiples modalitats o combinant diferents mètodes de classi cació. Donat que incrementar el número de modalitats, representa a la vegada problemes pels usuaris, moltes d'aquestes aproximacions no arriben mai al mercat. La tesis contribueix principalment en tres grans àrees, totes elles amb el denominador comú següent: Reconeixement biometric a través de les mans. i) La primera d'elles constitueix la base de qualsevol estudi, les dades. Per poder interpretar, i establir un sistema de reconeixement biomètric prou robust amb un clar enfocament a múltiples fonts d'informació, però amb el mínim esforç per part de l'usuari es construeix aquesta Base de Dades de mans multi espectral. Les bases de dades biomètriques constitueixen un recurs molt preuat per a la recerca; sobretot si ofereixen algun element nou com es el cas. Imatges de mans en diferents espectres electromagnètics: en visible (VIS), en infraroig (NIR) i en tèrmic (TIR). Amb un total de 100 usuaris, i 10 mostres per usuari, constitueix un bon punt de partida per estudiar i posar a prova sistemes multi biomètrics enfocats a les mans. ii) El segon bloc s'adreça a les dues aproximacions existents en la literatura per a tractar les dades en brut. Aquestes dues aproximacions, anomenades Holística (tracta la imatge com un tot) i Geomètrica (utilitza càlculs geomètrics) de neixen el focus alhora d'extreure el vector de característiques. Abans de tractar alguna d'aquestes dues aproximacions, però, és necessària l'aplicació de diferents tècniques de preprocessat digital de la imatge per obtenir les regions d'interès desitjades. Diferents problemes presents a les imatges s'han hagut de solucionar de forma original per a cadascuna de les tipologies de les imatges presents: VIS, NIR i TIR. VIS: imatges sobre exposades, anells, mànigues, braçalets. NIR: Ungles pintades, distorsió en forma de soroll en les imatges TIR: Dits freds La segona àrea presenta aspectes innovadors, ja que a part de segmentar la imatge de la ma, es segmenten tots i cadascun dels dits (feature-based approach). Així aconseguim contrastar la seva capacitat de reconeixement envers la ma de forma completa. Addicionalment es presenta un conjunt de procediments geomètrics amb la idea de comparar-los amb els provinents de l'extracció holística. La tercera i última àrea contrasta el procediment de classi cació anomenat Biometric Dispersion Matcher (BDM) amb diferents situacions. La primera relacionada amb l'efectivitat respecte d'altres mètode de reconeixement, com ara l'Anàlisi Lineal Discriminant (LDA) o bé mètodes com KNN o la regressió logística. Les altres situacions que s'analitzen tenen a veure amb múltiples fonts d'informació, quan s'apliquen tècniques de normalització i/o estratègies de combinació (fusió) per millorar els resultats. Els resultats obtinguts no deixen lloc per a la confusió, i són certament prometedors en el sentit que posen a la llum la importància de combinar informació complementària per obtenir rendiments superiors.
Karlsson, Jonas. "FPGA-Accelerated Dehazing by Visible and Near-infrared Image Fusion." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-28322.
Full textCosta, Posada Carlos Rufino. "The topographic effect in visible and near infrared satellite imagery." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624720.
Full textKarkoschka, Erich. "Saturn's atmosphere in the visible and near-infrared, 1986-1989." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185074.
Full textAmat, Genís Albert. "Effect of visible and near-infrared light on adenosine triphosphate (atp)." Doctoral thesis, Universitat Rovira i Virgili, 2005. http://hdl.handle.net/10803/8715.
Full textInteraccio llum-materia
L'energia electromagnetica l'ona de la qual oscil.la en una longitud d'ona de nanometres es anomenada llum. En aquestes frequencies, l'energia promou excitacio electronica de certs atoms i molecules. Existeix una interaccio diferent de la llum amb molecules, produida per el camp electromagnetic que per definicio la llum provoca en qualsevol medi. El camp electric resultant desplaca els electrons dels enllacos quimics produint una polaritzacio del medi sense que existeixi absorcio de l'energia. Aquest es un mecanisme interactiu que existeix sempre, i es l'unic que es dona en molecules que son transparents (no absorbeixen) per a una determinada frequencia de la llum, com es el cas de l'ATP per l'energia visible i infravermella propera.
Experiments, resultats i discussio
Quan l'ATP es excitat amb fotons ultraviolats, es produiex una fluorescencia en longituts d'ona visibles. L'io magnesi s'ha utilitzat per estudiar com la llum visible i infravermella propera produiex un desplacament de carregues electriques a la molecula d'ATP.
La construccio d'un interferometre de Michelson ha servit per observar l'interaccio no absortiva de la llum i l'ATP. La mesura directa de l'index de refraccio d'una solucio d'ATP dona informacio sobre les caracteristiques electriques del medi. L'observacio de que aquest index canvia despres d'irradiar la solucio amb longituds d'ona visibles i infravermelles properes, confirmen que la llum provoca canvis electrics significatius en l'ATP.
En aquest treball tambe s'ha estudiat el comportament bioquimic de l'ATP irradiat quant forma part de dues reaccions quimiques diferents: la de la luciferina-luciferasa i la de la hexoquinasa. En tots dos casos, l'us d'aquest ATP irradiat ha produit una alteracio dels parametres cinetics estudiats, V0 i k en la reaccio de la luciferina-luciferasa, i km i vmax en la reaccio de l'hexoquinasa.
Conclusions
Aquesta interaccio no absortiva de la llum amb l'ATP es la primera descrita per a una biomolecula. El mecanisme aporta noves dades per explicar els efectes observats en el metabolisme cel.lular despres de l'irradiacio d'organismes, teixits i cultius cel.lulars amb llum visible i infravermella propera.
ATP is a key molecule in cellular metabolism. In this thesis, I examined the effects of visible (635 and 655 nm) and near-infrared (810 and 830 nm) light on ATP in solution. I also examined were the biochemical behavior of light-exposed ATP in the luciferine-luciferase reaction and hexokinase reaction, the initial step in glycolysis that begins extra mithocondrial ATP synthesis. Irradiated groups in the luciferine-luciferase reaction showed an improvement in the kinetic parameters V0 and k, and more ATP molecules reacted with the enzyme when they were excited by light. When irradiated ATP was added to the hexokinase reaction, the experimental groups showed significant differences in the Michaelis-Menten kinetic parameters (km for ATP and vmax) and the rate of product synthesis was greater. Changes in both reactions were wavelength and dose dependant.
When ATP was excited with UV photons, it fluoresced. This fluorescence decreased when Mg2+ was added, probably because the ion binds the phosphates, which are the part of the molecule responsible for light emission. Irradiating the ATP-Mg2+ solution with 655 nm and 830 nm light increased the fluorescence resulting from a displacement of charges in the phosphor-oxygen bond that repels Mg2+.
The refraction of light in an ATP solution was observed by the Michelson interferometer and by directly measuring the refractive index. The refractive index changed after red and near-infrared light interaction due to a change in the electrical permittivity of the medium.
Since ATP in water is transparent to visible and near-infrared light, and is therefore not a chromophore for those wavelengths, I conclude that the observed light interaction with ATP is not due to photon absorption but to the electromagnetic disturbance produced by the light, which leads to a polarization of the dielectric molecule that is ATP.
This interaction of visible and near-infrared electromagnetic energy with ATP offers new perspectives for explaining light interaction at subcellular level.
Buchanan, Bruce Randall. "Compatability of optical-fiber measurements with near-infrared and visible analysis /." Thesis, Connect to this title online; UW restricted, 1987. http://hdl.handle.net/1773/11591.
Full textWerts, Martinus Henricus Valentinus. "Luminescent lanthanide complexes visible light sensitised red and near-infrared luminescence /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/83075.
Full textGoswami, D. "Cross-spectral face recognition between near-infrared and visible light modalities." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580573.
Full textOlatunde, Kofoworola Amudat. "Soil characterization using Visible Near Infrared Diffuse Reflectance Spectroscopy (VNIR DRS)." Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/78986/.
Full textHobson, Mélissa J. "Exoplanet detection around M dwarfs with near infrared and visible spectroscopy." Thesis, Aix-Marseille, 2019. http://theses.univ-amu.fr.lama.univ-amu.fr/191008_HOBSON_772b933qvb68s859flllx_TH.pdf.
Full textExoplanet science has begun to focus on M-dwarf stars for exoplanet detection and characterisation. They are the most common stars in the galaxy; their small size means smaller exoplanets can be detected; habitable zone planets are easier to detect as it is closer to the star. The emerging population of M dwarf planets shows intriguing characteristics compared to those hosted by FGK stars. The aim of this thesis is to explore the detection of exoplanets around M dwarfs via the radial velocity method, in both the near infra-red and visible domains. I also performed analyses of the known population of planets around M dwarfs at the start of the thesis and at its conclusion. In the visible, I worked with the SOPHIE spectrograph at the OHP, as part of the SOPHIE exoplanets consortium. This group leads several exoplanet surveys, one of which searches for planets around M dwarfs. I adapted a template-matching algorithm to its targets, and analysed the resulting radial velocities. I confirmed the significance of periodic signals that, while apparent in the standard analysis, were partially hidden by noise. Four new exoplanets have been published. I studied stellar activity indicators, identifying those most suited to SOPHIE spectra. In the near infrared, I worked with the SPIRou spectropolarimeter at the CFHT. This new instrument was conceived for observing M dwarfs, which emit most of their radiation in the infrared. I worked on the data reduction pipeline, specifically on the wavelength solution (pixel position-wavelength correspondence), crucial for measuring precise radial velocities. I developed and tested ways to combine different wavelength calibrators
OGLESBY, PAUL HARVEY. "GLOBAL SOLAR OSCILLATIONS OBSERVED IN THE VISIBLE TO NEAR-INFRARED CONTINUUM." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184176.
Full textFarrand, William Halsey. "Visible and near infrared reflectance of tuff rings and tuff cones." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185423.
Full textEralp, Muhsin. "Visible and Near Infrared Sensitive Photorefractive Polymers for Holographic Display Applications." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195723.
Full textD’Incecco, P. (Piero). "Visible and near infrared spectroscopy of Mercury and Venus from orbit." Doctoral thesis, University of Oulu, 2017. http://urn.fi/urn:isbn:9789526215068.
Full textOriginal papers Piero D’Incecco, Jörn Helbert, Mario D’Amore, Alessandro Maturilli, James W. Head, Rachel L. Klima, Noam R. Izenberg, William E. McClintock, Harald Hiesinger, Sabrina Ferrari, Shallow crustal composition of Mercury as revealed by spectral properties and geological units of two impact craters, Planetary and Space Science, Volume 119, 15 December 2015, Pages 250-263, ISSN 0032-0633, http://dx.doi.org/10.1016/j.pss.2015.10.007. (http://www.sciencedirect.com/science/article/pii/S0032063315003062) Keywords: Mercury; MESSENGER; MASCS; MDIS; Impact craters; Stratigraphy Piero D’Incecco, Jörn Helbert, Mario D’Amore, Sabrina Ferrari, James W. Head, Alessandro Maturilli, Harald Hiesinger, A geologically supervised spectral analysis of 121 globally distributed impact craters as a tool for identifying vertical and horizontal heterogeneities in the composition of the shallow crust of Mercury, Planetary and Space Science, Volume 132, 1 November 2016, Pages 32-56, ISSN 0032-0633, http://dx.doi.org/10.1016/j.pss.2016.08.004. (http://www.sciencedirect.com/science/article/pii/S0032063315301094) Keywords: Mercury; MESSENGER; MASCS; MDIS; Impact craters; Datasets Fusion Techniques (DFTs) Piero D'Incecco, Nils Müller, Jörn Helbert, Mario D'Amore, Idunn Mons on Venus: Location and extent of recently active lava flows, Planetary and Space Science, Volume 136, February 2017, Pages 25-33, ISSN 0032-0633, http://dx.doi.org/10.1016/j.pss.2016.12.002. (http://www.sciencedirect.com/science/article/pii/S003206331630112X) Keywords: Venus; VIRTIS; Magellan; Volcanism; Idunn Mons; Stratigraphy
Samanta, Goutam Kumar. "High-power, continuous-wave optical parametric oscillators from visible to near-infrared." Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/29963.
Full textEsta tesis presenta el desarrollo de una nueva clase de osciladores ópticos paramétricos (OPOs) de onda continua (cw) y alta potencia con extendida sintonización desde el visible al infrarrojo (IR) cercano. A pesar de que los láseres están en uso desde hace casi 50 años, todavía es difícil desarrollar sistemas láser que puedan cubrir muchas regiones del espectro óptico en los rangos de longitud de onda desde el ultravioleta (UV) y visible hasta el infrarrojo cercano y medio, con potenciales aplicaciones en campos como la espectroscopia, sensores remotos, detección de trazas de gases, entre muchas otras. El desarrollo de cw OPOs en configuraciones de oscilador simplemente resonante (SRO), objetivo principal de esta tesis, es un gran desafío debido al alto umbral de potencia de bombeo (varios watts). Además, cuando se emplea bombeo visible, los efectos fotorrefractivo y de lente térmica adquieren especial relevancia y son difíciles de superar. Por lo tanto, la realización de cw SROs prácticos requiere de un óptimo diseño de cavidad, adecuados materiales no lineales y láseres de alta potencia con excelente calidad tanto espectral como espacial. Se han desarrollado cw SROs de alta potencia y frecuencia única basados en cristales de LiTaO3 de 30 mm de longitud, de crecido estequiométrico, con dopado de MgO y periódicamente pulidos (MgO:sPPLT). Los osciladores fueron bombeados en el verde mediante el láser de cw Nd:YVO4 bombeado por diodos y doblado en frecuencia. Utilizando un único periodo de red de 7.97 m, se ha obtenido cobertura continua de los campos señal y pivote en el rango 848-1430 nm por sintonización de temperatura entre 52ºC y 248ºC. Empleando una configuración de cavidad lineal y bombeo de doble paso, se ha logrado un umbral de oscilación de 2.88 W y se han generado potencias superiores a 1.51 W para el campo pivote en simple paso dentro del rango 1104-1430 nm para 6 W de potencia de bombeo, eficiencia de extracción del 25.2% y eficiencia de conversión de fotón del 56.7%. Con el objetivo de operar el cw SRO en frecuencia única a través del rango 848-1430 nm, hemos utilizado una configuración compacta de cavidad en anillo junto a un elemento para la selección de frecuencia (etalon). Utilizando el mismo cristal de MgO:sPPLT, se ha obtenido un umbral de oscilación del SRO de 2.84 W y se han generado potencias superiores a 1.59 W para el campo pivote en paso único dentro del rango 1104-1430 nm con una eficiencia máxima de extracción del 25.2 % y agotamiento del bombeo tan alto como el 67%. La salida del campo pivote en frecuencia única tiene un ancho de línea de ~ 7 MHz. Bajo condiciones de sistema libre y en ausencia de aislamiento térmico, la potencia del campo pivote exhibe estabilidad de pico a pico de 16% durante 5 horas. A pesar de que el cw SRO puede proveer radiación óptica en el rango 848-1430 nm, la alta potencia de salida solo se consiguió obtener en el rango 1104-1430 nm a causa de la alta reflectividad de los espejos de la cavidad para operar en SRO. Utilizando un acoplamiento de salida finito de la onda resonante, hemos extendido la disponibilidad de prácticas potencias de salida a través de todo el rango de sintonía. El cw SRO con acoplador de salida (OC-SRO) puede entregar un apotencia total de hasta 3.6 W con una eficiencia de extracción del 40% y con un ancho de línea de 3 MHz en el rango 848-1430 nm. La potencia del campo señal muestra fluctuaciones en potencia de pico a pico <10.7% durante 40 minutos y modo espacial TEM00 con M2<1.52. En ausencia de estabilización activa, el campo señal resonante exhibe una estabilidad en frecuencia natural a largo término con fluctuaciones <75 MHz durante 15 minutos, así como a corto término con fluctuaciones<10MHz durante 10 segundos, demostrando el potencial del sistema para aplicaciones en espectroscopia. Utilizando generación interna de segundo harmónico del campo señal resonante en el rango del infrarrojo cercano del MgO:sPPLT cw SRO mediante un cristal de BiB3O6 de 5 mm de longitud, hemos logrado generar 1.27 W de potencia cw y frecuencia única en el azul dentro del rango de sintonía 425-489 nm y con un ancho de línea de 8.5 MHz y un perfil espacial del haz de tipo Gaussiano. La estabilidad en frecuencia de la fuente azul es mejor que 280 MHz, donde la limitación viene impuesta por la resolución del medidor de longitud de onda empleado. Adicionalmente, hemos desarrollado fuentes verdes en cw en una sencilla configuración experimental de único paso, mediante el doblado en frecuencia de un láser de fibra con cristales de MgO:sPPLT y KTiOPO4 pulido periódicamente (PPKTP), generando hasta 9.6 W de radiación verde en modo espacial TEM00 (M2<1.33) con una eficiencia de paso único de 32.7% en MgO:sPPLT. Esta fuente verde has sido también empleada exitosamente para bombear cw SROs y será utilizada para bombear láseres de Ti:sapphire. Mediante esta fuente verde doblada en frecuencia, hemos demostrado que el cw OC-SRO proporciona una salida estable en frecuencia única con potencia de hasta 2 W a través del rango de sintonía 855-1408 nm, con estabilidad en potencia de pico a pico <11.7%, estabilidad en frecuencia <10 MHZ durante 10 segundos y modo espacial TEM00 (M2<1.26).
Lafarga, Magro Marina. "Stellar activity and exoplanets ofMdwarfs from CARMENES visible to near-infrared spectroscopy." Doctoral thesis, Universitat Autònoma de Barcelona, 2020. http://hdl.handle.net/10803/671618.
Full textDespués del descubrimiento de los primeros exoplanetas hace unas tres décadas, la detección y caracterización de compañeros planetarios se ha convertido en un tema de investigación prominente, especialmente la búsqueda de planetas parecidos a la Tierra, cuerpos rocosos que orbitan en la zona habitable (HZ) de sus estrellas huéspedes. Uno de los principales métodos utilizados para encontrar y caracterizar exoplanetas es la técnica de la espectroscopía Doppler o velocidad radial (RV), basada en el uso de espectros estelares para medir cambios periódicos en la RV de una estrella causados por la atracción gravitatoria de un exoplaneta en órbita. Actualmente, la variabilidad intrínseca de las estrellas huéspedes es el principal reto en el estudio de exoplanetas. Las estrellas no son cuerpos invariables ni homogéneos, sino que presentan variabilidad en distintas escalas de tiempo. La más relevante es la actividad magnética estelar, que incluye fenómenos como manchas o fáculas que aparecen en la superficie de la estrella y están moduladas por su rotación. Estos fenómenos distorsionan los espectros estelares, introduciendo sesgos en las RVs suficientemente grandes como para esconder o hasta imitar la señal causada por un planeta. Por lo tanto, para continuar detectando y estudiando exoplanetas de baja masa, una mejor comprensión de estos fenómenos estelares y sus efectos en nuestras observaciones es clave. Esta tesis se centra en el estudio de los efectos de la actividad estelar en observaciones espectroscópicas de estrellas frías obtenidas con el instrumento CARMENES. CARMENES es un espectrógrafo de alta resolución capaz de observar en el rango de longitudes de onda visible e infrarojo cercano. Está realizando un estudio de más de 300 enanas M, las estrellas con menor masa de la secuencia principal, con el objetivo primordial de detectar exoplanetas pequeños. En primer lugar, hemos desarrollado un código que implementa el método de la función de correlación cruzada (CCF) para medir RVs e indicadores de actividad estelar en observaciones de alta resolución, y lo hemos aplicado a los datos de CARMENES. Este método usa máscaras binarias ponderadas, un template estelar simplificado construido seleccionando líneas espectrales. Hemos creado varias máscaras en función del subtipo espectral y de la velocidad de rotación de la estrella a analizar. A continuación, hemos utilizado los indicadores de actividad derivados de la CCF, juntamente con otros indicadores de actividad espectroscópicos, para analizar sus variaciones temporales en una muestra de casi 100 enanas M de varias masas y niveles de actividad. Aproximadamente la mitad de las estrellas analizadas muestran RVs con señales de actividad claros. Distintos indicadores son sensibles a la actividad de forma diferente según las características de la estrella: indicadores cromosféricos son más útiles para estrellas de baja actividad, indicadores relacionados con el cambio de RV con la longitud de onda funcionan mejor para estrellas más activas, y otros indicadores relacionados con el cambio de anchura de las líneas fotosféricas proporcionan resultados similares en todo tipo de estrellas, pero son especialmente útiles para las más activas y de menor masa. Finalmente, hemos analizado los efectos de la actividad sobre líneas de absorción individuales presentes en el espectro de estrellas activas. Estudiando las correlaciones entre las RVs de líneas individuales y los indicadores de actividad, podemos clasificar las líneas observadas según su sensibilidad a la actividad. Esto nos permite seleccionar líneas afectadas de forma distinta por la actividad y usarlas para volver a calcular RVs. De esta forma obtenemos RVs para las cuales mitigamos o incrementamos la señal de actividad en diversos grados. También observamos que las mismas líneas en distintas estrellas muestran diferente sensibilidad a la actividad.
After the discovery of the first exoplanets about three decades ago, the detection and characterization of planetary companions has become a prominent research topic, especially the search for Earth-like planets, rocky bodies orbiting in the habitable zone (HZ) of their host stars. One of the main methods used to find and characterise exoplanets is the Doppler spectroscopy or radial velocity (RV) technique, based on using stellar spectra to measure periodic changes in the RV of a star caused by the gravitational pull of an orbiting exoplanet. Currently, the intrinsic variability of the host stars is the major challenge faced in the study of exoplanets. Stars are not quiet, homogeneous bodies, but display variability on different timescales, the most concerning being stellar magnetic activity, phenomena such as spots or faculae appearing on the stellar surface and modulated by the stellar rotation. These features distort the stellar spectra, introducing biases in our RVs that can be large enough to hide or even mimic the signal caused by a planet. Therefore, to continue detecting and studying low-mass exoplanets, a better understanding of these stellar phenomena and their effects on our observations is key. This thesis is focused on the study of stellar activity effects on spectroscopic observations of cool stars obtained with the CARMENES instrument. CARMENES is a high-resolution spectrograph capable of observing on the visible and near-infrared wavelength ranges. It is performing a survey of over 300 M dwarfs, stars at the low-mass end of the main sequence, with the main goal of detecting small exoplanets. Firstly, we developed a pipeline that implements the cross-correlation function (CCF) method to measure RVs and indicators of stellar activity on high-resolution observations, and applied it to the CARMENES survey data. This method uses weighted binary masks, a simplified stellar template built by selecting sharp spectral lines, of which we created different kinds depending on the spectral subtype and the rotational velocity of the target star. We then used the activity indicators derived from the CCF, together with other spectroscopic activity proxies, to analyse their temporal variations in a sample of almost 100 M dwarfs with a range of masses and activity levels. We found that about half of the stars analysed show RVs with clear signals of activity. Different indicators trace activity differently depending on the characteristics of the star: chromospheric indicators are the most useful for low-activity stars, indicators related to the change in RV with wavelength work better for the most active stars, and other indicators related to the change in width of the photospheric lines provide similar results in all types of stars, but are especially useful for the most active and lowest-mass ones. Finally, we analysed the effects of activity on individual absorption features present on the spectra of active stars. By studying the correlations between the individual line RVs and activity indicators, we are able to classify the observed lines according to their sensitivity to activity. This allow us to select differently affected lines and use them to recompute RVs for which we mitigate or enhance the activity signal to varying degrees. We also observe that the same lines on different stars show different sensitivities to activity.
Flowerdew, Roland John. "Atmospheric correction for the visible and near-infrared channels of ATSR-2." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283392.
Full textWaiser, Travis Heath. "In situ characterization of soil properties using visible near-infrared diffuse reflectance spectroscopy." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/5915.
Full textDavis, Christopher Brent Busch Kenneth W. Busch Marianna A. "Application of chemometric analysis to UV-visible and diffuse near-infrared reflectance spectra." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5042.
Full textChen, Limei. "Non-destructive measurement of tomato quality using visible and near-infrared reflectance spectroscopy." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32405.
Full textDes essais visant à évaluer la faisabilité d'utiliser la spectroscopie de réflectance dans le visible et le proche infrarouge (VIS/PIR) pour déterminer certaines caractéristiques contribuant à la qualité de la tomate (Lycopersicon esculentum Mill. cv. 'DRK 453' et 'Trust') ont été menés. Une analyse de régression partielle par les moindres carrés a servi à bâtir des modèles de prédiction. D'excellentes prédictions ont été obtenues pour la teneur en lycopène (TL), la valeur chromatique a*/b*, l'indice de couleur de la tomate (ICT), et la fermeté. Les coefficients de détermination (R2) pour chacun de ces paramètres ont été de 0.96, 0.99, 0.99 et 0.97. Tous ces R2 ont été significatifs à un niveau de 1%. L'erreur-type de prédiction (ETP) a été petite pour tous ces paramètres, indiquant un très bon degré d'ajustement des modèles. Des valeurs d'ETP de 2.15, 0.06, 1.52 et 1.44 ont respectivement été obtenues pour le TL, le rapport a*/b*, l'ICT, et la fermeté. Cependant, les modèles visant à prédire l'acidité totale, la teneur en solides solubles et le rapport acide-Brix se sont montrés peu fiables avec des valeurs respectives de R2 de 0.49, 0.03 et 0.65 et de ETP de 0.43, 0.15 et 0.08. De plus, un modèle multivariable bâti par une méthode de régression partielle par des moindres carrés (PLS2) s'est montrée très performant pour la prédiction simultanée du rapport a*/b*, de l'ICT, de la fermeté et de la TL avec des valeurs respectives de R2 de 0.99, 0.99, 0.97 et 0.92 et de ETP de 0.06, 1.75, 1.44 et 3.03. Comme auparavant toutes les valeurs de R2 ont été significatives à un niveau de 1%.
Glendinning, J. H. G. "The modelling of radiative transfer in snow at visible and near infrared wavelengths." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388150.
Full textCozzolino, Gomez Daniel. "Visible and near infrared reflectance spectroscopy (NIRS) for the assessment of flesh foods." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265208.
Full textLomanowski, Bartosz Aleksander. "Visible and near-infrared divertor spectroscopy on the MAST and JET-ILW tokamaks." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/11437/.
Full textReid, Derryck T. "Novel nonlinear techniques for femtosecond pulse generation in the visible and near-infrared." Thesis, University of St Andrews, 1995. http://hdl.handle.net/10023/14885.
Full textGad, Gad Mansour Ahmed. "Stimulated scattering in solids and new Raman lasers in near infrared and visible regions." [S.l.] : [s.n.], 2003. http://edocs.tu-berlin.de/diss/2003/gad_gad.pdf.
Full textMamaikin, Mikhail [Verfasser], and Ferenc [Akademischer Betreuer] Krausz. "Time-resolved microscopy of near-infrared to visible waveforms / Mikhail Mamaikin ; Betreuer: Ferenc Krausz." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/121549985X/34.
Full textOkparanma, R. N. "Rapid measurement of polycyclic aromatic hydrocarbon contamination in soils by visible and near-infrared spectroscopy." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8063.
Full textAlves, Vaccari Paulo Roberto. "Near infrared and visible optical properties in electrochromic crystalline tungsten oxide thin films on ITO." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-229122.
Full textLiu, Lanfa, Min Ji, and Manfred F. Buchroithner. "Combining Partial Least Squares and the Gradient-Boosting Method for Soil Property Retrieval Using Visible Near-Infrared Shortwave Infrared Spectra." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232271.
Full textLiu, Lanfa, Min Ji, and Manfred F. Buchroithner. "Combining Partial Least Squares and the Gradient-Boosting Method for Soil Property Retrieval Using Visible Near-Infrared Shortwave Infrared Spectra." Molecular Diversity Preservation International (MDPI), 2017. https://tud.qucosa.de/id/qucosa%3A30734.
Full textLiu, Lanfa, Manfred Buchroithner, Min Ji, Yunyun Dong, and Rongchung Zhang. "Quantitative Retrieval of Organic Soil Properties from Visible Near-Infrared Shortwave Infrared (Vis-NIR-SWIR) Spectroscopy Using Fractal-Based Feature Extraction." Molecular Diversity Preservation International (MDPI), 2016. https://tud.qucosa.de/id/qucosa%3A30203.
Full textLiu, Lanfa, Manfred Buchroithner, Min Ji, Yunyun Dong, and Rongchung Zhang. "Quantitative Retrieval of Organic Soil Properties from Visible Near-Infrared Shortwave Infrared (Vis-NIR-SWIR) Spectroscopy Using Fractal-Based Feature Extraction." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-220555.
Full textOgden, Chad E. "A prototype visible to near-infrared spectrograph for the CHARA array a long-baseline stellar interferometer /." unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-11282005-121433/.
Full textTheo A. ten Brummelaar, committee chair; Brian D. Thoms, Todd J. Henry, William G. Bagnuolo, Douglas R. Gies, Harold A. McAlister, committee members. Author's name from thesis t.p. Electronic text (548 p. : ill.) : digital, PDF file. Description based on contents viewed June 27, 2007; title from title screen. Includes bibliographical references (p. 539-548).
Ogden, Chad Elliott. "A Prototype Visible to Near-Infrared Spectrograph for the CHARA Array, a Long-Baseline Stellar Interferometer." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/phy_astr_diss/4.
Full textZhou, Gang. "ZnSe ceramics and phosphate glasses for optical applications in the visible and infrared ranges." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S071/document.
Full textA two-part study was conducted on the preparation and characterization of ZnSe ceramic and phosphate glasses for optical applications in the visible and infrared range. To prepare ZnSe powders, two synthetic routes were used: i) hydrothermal; ii) ball milling. The size and morphology of synthesized powders were analyzed using different techniques (XRD, SEM…). Then two sintering technologies, hot pressing (HP) sintering and spark plasma sintering (SPS) sintering have been implemented to obtain optically transparent ZnSe bulk samples. The best transmission obtained in the mid-infrared range, using HP and SPS, is greater than 50% and 40% respectively. To synthesize phosphate glasses with a high chemical durability, cations with high field strength such as Nb5+ and Ti4+ were incorporated into a phosphate matrix. The transparency in the visible range was obtained using small amounts of oxidation agents such as sulfates or nitrates. The use of diffuse reflectance spectroscopy led to determination of the chromaticity coordinates to evaluate the benefit of these additions
Booso, Benjamin David. "The Growth of Columnar Thin Films and Their Characterization Within the Visible and Near Infrared Spectral Bands." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1272587327.
Full textAkiya, Yusuke. "Visible and near-infrared airglow structures in the mesosphere and the lower thermosphere observed by space-borne instruments." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199107.
Full textPiradi, Venkatesh. "Visible and near-infrared absorbing porphyrin-dimer based acceptor-donor-acceptor small molecules for organic solar cell applications." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/808.
Full textJohnson, Jeffrey R., Cherie Achilles, James F. Bell, Steve Bender, Edward Cloutis, Bethany Ehlmann, Abigail Fraeman, et al. "Visible/near-infrared spectral diversity from in situ observations of the Bagnold Dune Field sands in Gale Crater, Mars." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626566.
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