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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Registro de imagens por correlação de fase para geração de imagens coloridas em retinógrafos digitais utilizando câmera CCD monocromática / Image registration using phase correlation to generate color images in digital fundus cameras using monochromatic CCD camera

José Augusto Stuchi 10 June 2013 (has links)
A análise da retina permite o diagnostico de muitas patologias relacionadas ao olho humano. A qualidade da imagem e um fator importante já que o médico normalmente examina os pequenos vasos da retina e a sua coloração. O equipamento normalmente utilizado para a visualização da retina e o retinógrafo digital, que utiliza sensor colorido com filtro de Bayer e luz (flash) branca. No entanto, esse filtro causa perda na resolução espacial, uma vez que e necessário um processo de interpolação matemática para a formação da imagem. Com o objetivo de melhorar a qualidade da imagem da retina, um retinógrafo com câmera CCD monocromática de alta resolução foi desenvolvido. Nele, as imagens coloridas são geradas pela combinação dos canais monocromáticos R (vermelho), G (verde) e B (azul), adquiridos com o chaveamento da iluminação do olho com LED vermelho, verde e azul, respectivamente. Entretanto, o pequeno período entre os flashes pode causar desalinhamento entre os canais devido a pequenos movimentos do olho. Assim, este trabalho apresenta uma técnica de registro de imagens, baseado em correlação de fase no domínio da frequência, para realizar precisamente o alinhamento dos canais RGB no processo de geração de imagens coloridas da retina. A validação do método foi realizada com um olho mecânico (phantom) para a geração de 50 imagens desalinhadas que foram corrigidas pelo método proposto e comparadas com as imagens alinhadas obtidas como referência (ground-truth). Os resultados mostraram que retinógrafo com câmera monocromática e o método de registro proposto nesse trabalho podem produzir imagens coloridas da retina com alta resolução espacial, sem a perda de qualidade intrínseca às câmeras CCD coloridas que utilizam o filtro de Bayer. / The analysis of retina allows the diagnostics of several pathologies related to the human eye. Image quality is an important factor since the physician often examines the small vessels of the retina and its color. The device usually used to observe the retina is the fundus camera, which uses color sensor with Bayer filter and white light. However, this filter causes loss of spatial resolution, since it is necessary a mathematical interpolation process to create the final image. Aiming at improving the retina image quality, a fundus camera with monochromatic CCD camera was developed. In this device, color images are generated by combining the monochromatic channels R (red), G (green) and B (blue), which were acquired by switching the eye illumination with red, green and blue light, respectively. However, the short period between the flashes may cause misalignment among the channels because of the small movements of the eye. Thus, this work presents an image registration technique based on phase correlation in the frequency domain, for accurately aligning the RGB channels on the process of generating retina color images. Validation of the method was performed by using a mechanical eye (phantom) for generating 50 misaligned images, which were aligned by the proposed method and compared to the aligned images obtained as references (ground-truth). Results showed that the fundus camera with monochromatic camera and the method proposed in this work can produce high spatial resolution images without the loss of quality intrinsic to color CCD cameras that uses Bayer filter.
62

Měření polohy a rychlosti objektů pomocí řádkových optických snímačů / Measurements of the object position and velocity by using optical scanners

Uncajtik, Petr January 2008 (has links)
The objective of Master’s Thesis is to research the utilization of line optical sensors for object location´s and speed measurement in cooperation with PROTOTYPA company. At the beginning of the Thesis there is an explanation of CCD sensor components and photodiods working principals. Further are discussed particular methods of object sensing. There are schematics of different sensor locations and flying object. The other step deals with introduction to the question of ray impact on sensor in the way of using different light sources and optical systems. In the other part of the Thesis are presented two sensors, which have been chosen by PROTOTYPA company workers. Final part of the Thesis deals with description of executed experimental measurement with LCCD 2048S-14 type of sensor. Experiments are aimed for statical and dynamical processes. In statical part was checked displaying of fixed objects on CCD sensor in internal spaces on the assumption that changing of object-lens focalization, object´s high and shape. For the evaluation was used of MATLAB program. Dynamical part of measurement is aimed for moving objects.
63

Adaptabilní obrazový A/D převodník / Adaptable video A/D converter

Maňas, Stanislav January 2012 (has links)
Master's Thesis deals with the complete proposal of light adaptability A/D converter. In the second chapter there are describes types of sensors. Third one describes the most used methods of light adaptability. In the fourth chapter there is describe the adaptability A/D conversion. Chapter 5 describes the block diagram. In the sixth chapter there is the design of all blocks of A/D converter. Finally in the chapter 7 there are construction documents for realization.
64

Testování systému pro astronomické určování polohy MAAS-1 / Testing of astronomical positioning system MAAS-1

Kremser, Christian January 2013 (has links)
This thesis deals with testing of astronomical measurement system MAAS-1, which was developed at the Institute of Geodesy, Faculty of Civil Engineering, Brno University of Technology. Several reference measurements were done on the terrace of B building Faculty of Civil Engineering during this testing. The data obtained were processed into astronomical geographic coordinates and . These coordinates, as well as atmospheric conditions and calibration measurements, are basis for evaluation. In this test I try to detect the influence of the CCD sensor mounting of the accuracy on the final data and to assess if the construction needs to be modified.
65

Návrh kontrolního přípravku pro plastový výrobek interiéru osobního vozidla / The design of test fixture for plastic part of car interior

Peňák, Vlastimil January 2016 (has links)
This diploma thesis deals with the development, disign and manufacturing inspection device that is able to detect the presence of components in the assembly of the plastic molding. Evaluation of information are indicated by the operator device and sent for further processing. Rechecked product will be marked with a uniquemark.
66

Spectroscopic studies of the tropospheric boundary layer

Norton, Emily G. January 2006 (has links)
This thesis presents a development to the technique of rotational Raman lidar by, incorporating an imaging spectrometer in conjunction with a clocking CCD detection system. This allowed the rotational Raman spectra of nitrogen and oxygen to be simultaneously recorded as a function of altitude. The rotational Raman spectra were uses to calculate temperature profiles. Recording the complete band envelopes of the rotational Raman spectra removed the need for an external reference, such as a radiosonde. Results are presented from measurements made in Cambridge in chapter 4 and Ny-Alesund in chapter 6. Chapter 7 presents some conventional lidar backscatter measurements made using a PMT in Birmingham during the winter part of the pollution in the Urban Midlands Area (PUMA) campaign. These measurements were used to determine the cloud base and the planetarty boundary layer height. Two automated algorithms were tested at retrieving the PBL height, the inflection point method and the centroid method.
67

Reduced information integral imaging

Brewin, Michael A. January 1998 (has links)
No description available.
68

Study of radiative properties : application to fast determination of temperature and iron concentration for MAG-P Arc (Ar-CO2-Fe mixtures) and to estimation of photobiological hazards for argon GTAW Arc / Etudes des propriétés radiatives : application à la détermination rapide de la température et de la concentration de fer pour un plasma d'arc MAG (mélanges Ar-CO²-Fe) et estimation des risques photobiologiques pour un arc GTAW dans l'argon

Wang, Fei 21 June 2018 (has links)
La première partie de ce travail présente une nouvelle méthode qui permet de détermination rapidement de la température et de la concentration en fer d'un plasma d'arc MAG utilisé dans la technologie de soudage par plasma. Le plasma est un mélange [Ar-CO2] en présence de fer, avec un rapport molaire entre Ar et CO2 constant de 82%-18%. La seconde partie s'intéresse au rayonnement d'un plasma d'argon utilisé dans la technologie soudage GTAW et pouvant conduire à des dangers photobiologique. Dans le chapitre 1, le contexte et la motivation de ce travail sont présentés. Les travaux déjà effectués et publiés dans ces deux axes scientifiques sont passés en revue. Dans le chapitre 2, les compositions à l'équilibre sont calculées par la méthode de la minimisation de l'énergie libre de Gibbs. Les densités et fonctions de partitions obtenues pour chaque espèces présente dans le plasma sont ensuite utilisées pour déterminer les pertes radiatives des plasmas [Ar-CO2]-Fe via la méthode du coefficient d'émission net (CEN). Cette estimation des pertes ne peut se faire sans le calcul préalable du coefficient d'absorption spectral que nous avons réalisé finement par la méthode " raie par raie ". Tous les mécanismes radiatifs prédominants dans le plasma ont été pris en compte: continua atomique et moléculaire, raies atomiques et moléculaires. Cette partie constitue la base de cette étude sur laquelle se fonde notre nouvelle méthode de diagnostic destinée à déterminer à la fois la température et la concentration en fer d'un plasma d'arc de soudage. Le chapitre 3 est dédié à l'étude expérimentale d'un plasma d'arc MAG constituée d'une analyse spectroscopique permettant de remonter au profil de température et tester l'hypothèse de l'Équilibre Thermodynamique Local. La température d'excitation est obtenue par la méthode de Boltzmann tandis que la mesure d'élargissement de Stark pour les raies de fer et d'argon permet de remonter à la température et la densité des électrons. / This PhD thesis introduces a method that allows the fast determination of temperature and iron concentration for MAG-P Arc. The MAG-P Arc is in fact [Ar-CO2]-Fe mixtures, with a constant molar ratio between Ar and CO2 [82%Ar-18%CO2]. In a second time, this thesis presents a study of the optical radiation associated to photobiological hazards for argon GTAW Arc. In chapter 1, the background and motivation of this work is introduced. The previous works published in this field are reviewed. In chapter 2, the equilibrium compositions are calculated firstly using the minimization of Gibbs free energy. Then the radiative properties of [Ar-CO2]-Fe plasmas are obtained in the frame of the net emission coefficient (NEC) approach, using the accurate "line by line" method. All significant radiative contribution mechanisms are taken into account in the calculation. This study will constitute a groundwork to build the diagnostic method that allows determination of temperature and iron concentration profiles in welding arc. In chapter 3, spectroscopic investigation of the LTE hypothesis across the MAG-P Arc is made. Excitation temperature is obtained with Boltzmann plot method while iron and argon lines Stark broadening measurements are used to get electron temperature and electron density. LTE hypothesis validity across the arc is discussed considering the agreement between the two temperatures, the electron density and iron content. Results show supporting evidence for the main part of the plasma, along radial and axial directions. Discrepancies occur only at the fringe of the arc, where the two temperatures differ by more than 2000 K. In chapter 4, a method allowing a fast determination of space- and time-resolved plasma temperature and iron concentration in MAG arcs during the high-current phase is introduced. This method consists in measuring the plasma spectral radiation of the arc with iron vapours using a high-speed camera filtered by narrow band filters in the spectral intervals of 570-590 nm and 606-627 nm respectively; calculating theoretically the dependence of the absolute emissivity e570-590 nm and relative emissivity e570-590 nm/e607-627 nm versus the plasma temperature and the iron concentration. This method has also been validated for a layer of plasma by adopting other existing diagnostics such as Stark broadening, which demonstrates the effectiveness of this new method. In chapter 5, a theoretical investigation of the UV (180-400 nm), UVA (315-400 nm) and blue light (300-700 nm) radiation associated with the photobiological hazards to workers for argon GTAW arcs is presented. The radiative properties of argon plasma are calculated for the three spectral regions, and a two-dimensional model of a GTAW arc is then developed to determine the local emissions in the arc, the total radiation escaping from the arc and corresponding effective irradiances. This study clearly supports the importance of undertaking an effective protection strategy for workers, particularly for skin and eyes, in the welding environment. Finally, a general conculsion is given in chapter 6.
69

Avaliação dos efeitos tóxicos da Mascagnia rigida em ratos. Estudo anatomopatológico. Comparação entre metodologias cromatográficas para detecção do fluoroacetato de sódio / Evaluation of Mascagnia rigida toxics effects, in rats. Pathological study. Comparison of chromatographics methods for sodium fluoracetate detection

Cunha, Luciana Castro da 24 March 2008 (has links)
O fluoroacetato de sódio (FAS), também conhecido como \"composto 1080\", foi um raticida amplamente utilizado no combate de roedores a partir da década de 40, mas que teve seu uso proibido em diversos países, incluindo o Brasil, devido a sua alta toxicidade e ausência de tratamento efetivo nas intoxicações. A despeito deste fato, diversos casos de intoxicação ainda são registrados em seres humanos e animais, em virtude de seu uso ilícito como raticida doméstico ou adição em iscas nas intoxicações criminosas. O FAS, na natureza, pode ser encontrado, também, em algumas plantas tóxicas de grande importância no Brasil, como a Palicourea marcgravii, e possivelmente seja o princípio ativo tóxico de outras plantas de relevância, como a Mascagnia rigida. Neste sentido, este trabalho objetivou o estudo dos aspectos clínicos e anatomopatológicos encontrados nas intoxicações provocadas pelo FAS, em ratos, comparando estes com os encontrados nas intoxicações por extrato aquoso da M. rígida. Também foram comparadas metodologias analíticas para identificação deste agente tóxico utilizando cromatografia em camada delgada (CCD) e cromatografia de alta eficiência (CLAE) com dois tipos de detectores o de UV e o de Condutividade Iônica. Para tanto, quatro grupos contendo seis ratos Wistar, machos, receberam em dose única por via oral 7,0 mg/kg de FAS ou água destilada ou ainda 1,6 ou 3,2 g/kg de extrato aquoso de M. rígida, sendo avaliados os sinais clínicos apresentados por estes animais. Após eutanásia foram coletados fragmentos de cérebro, coração, fígado, rins, pulmão, intestino e baço para exame histopatológico. Tanto os animais que receberam FAS como os que receberam extrato aquoso de M. rígida apresentaram sintomatologia similar com presença de prostração, desconforto respiratório, tremores, pêlos arrepiados, cromodacriorreia, convulsão tônica e tônico-clônica. Na necropsia destes animais não foram observadas alterações macroscópicas, contudo alterações histopatológicas significativas foram encontradas no cérebro, miocárdio, fígado e rins. Os estudos das análise toxicológicas utilizando as três técnicas cromatográficas mostraram que os resultados obtidos na CCD foram adequados para detecção de FAS nas concentrações acima de 1,0 μg do padrão puro e as análises das duas plantas estudadas apresentaram resultados positivos para FAS. As técnicas utilizando CLAE, com dois diferentes detectores, mostraram que quando se utiliza detector de UV o limite de detecção é de 3,75 μg injetado ou de 75 μg/mL e foi possível, também, detectar a presença de FAS nas duas plantas estudadas, porém a técnica não se apresentou adequada para a detecção de intoxicação em tecido animal. O detector de condutividade iônica mostrou limite de detecção de 0,30 μg/mL, isto é, o mais sensível entre os três métodos estudados, e portanto o mais adequado para diagnóstico de intoxicação em tecido animal; no entanto, para identificação do FAS na M. rigida este método não se mostrou adequado devido a interferentes no extrato aquoso e no soro de animais intoxicados. / Sodium fluoroacetate (SFA), also known as \"compound 1080,\" was a rodenticide widely used in the 1940s, but its use was banned in several countries, including Brazil, for its high toxicity and lack of an effective treatment in poisoning. Despite this fact, several cases of poisoning are still registered in humans and animals, because of their misuse as baits, in addition to criminal poisoning. SFA, in the form of natural molecules, can be found in some toxic plants of great importance in Brazil, such as Palicourea marcgravii, and possibly is the active principle of other plants of relevance, such as Mascagnia rigid. Therefore, this study aimed to evaluate the clinical and pathological findings in poisoning caused by the SFA in rats, and compare them with those found in poisoning by the aqueous extract of M. rigid. Moreover, we compared analytical methods for identifying this toxic agent using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) employing two types of detectors: ultraviolet (UV) and ionic conductivity. Therefore, four groups containing six male Wistar rats each, received a single oral dose of 7.0 mg / kg of SFA, an equal volume of distilled water, or 1.6 or 3.2 g / kg of an aqueous extract of M. rigid, and the clinical signs displayed by these animals were evaluated. After euthanasia fragments of brain, heart, liver, kidney, lung, intestine and spleen were collected for histological examination. Both the animals that received SFA and those who received the aqueous extract of M. rigid showed similar symptoms, including prostration, respiratory distress, tremors, shivering, and tonic or tonic-clonic seizures. At necropsy, these animals did not display macroscopic changes. Nevertheless, significant histopathological changes were found in the brain, heart, liver and kidneys. Toxicological analysis using the three chromatographic techniques described above showed that the results obtained in the TLC were suitable for detection of SFA at concentrations above 1.0 μg of pure standard, and analysis of the two plants mentioned showed positive results for SFA. The techniques using HPLC with two different detectors showed that when using the UV detector, the detection limit is of 3.75 μg (injected) or 75 μg / mL, and SFA could also be detected by these methods in the two plants studied, but the technique does not seem suitable for the detection of intoxication in animal tissue samples. The ionic conductivity detector showed a detection limit of 0.30 μg/ mL, therefore the most sensitive of the three methods studied, and hence is the most appropriate for diagnosis of poisoning in animal tissue; however, for the identification of SFA in the M. rigid, this method was not appropriate due to a putative interference in the aqueous extract.
70

Determinação de isoflavonas em formulações farmacêuticas / Determination of isoflavones in pharmaceutical formulations

Yano, Helena Miyoco 30 August 2006 (has links)
Fitoestrógenos são compostos naturais de origem vegetal com atividade estrogênica. Estão sendo amplamente investigados para a prevenção de doenças crônicas, coronarianas, câncer de próstata e mama, na redução de riscos de osteoporose e alívio nos sintomas da menopausa. Entre os fitoestrógenos já utilizados encontram-se a daidzeína, genisteína e gliciteína em matrizes complexas como drogas e extratos vegetais, cápsulas e comprimidos, requerendo desenvolvimento e validação de metodologias para a determinação das isoflavonas. As metodologias propostas foram a cromatografia em camada delgada de alta eficiência (CCDAE) e a cromatografia líquida de alta eficiência (CLAE). A fase móvel acetato de etila:hexano (8:2 v/v) foi utilizada para determinação do perfil cromatográfico das isoflavonas agliconas daidzeína, gliciteína e genisteína e a fase móvel acetato de etila:tolueno:ácido fórmico (8: 1: 1 v/v/v) para isoflavonas glicosiladas e não glicosiladas por CCDAE. Para a determinação quantitativa das isoflavonas glicosiladas por CLAE foi proposta uma hidrólise ácida com HCl 3M e aquecimento em banho-maria durante uma hora, como tratamento prévio. A determinação analítica das isoflavonas daidzeína, genisteína, formononetina e biochanina A por CLAE, em modo isocrático foi realizada utilizando coluna cromatográfica monolítica Chromolith® RP-18, 100-4,6mm, fase móvel constituída por água:acetonitrila (6:4 v/v), vazão 0,6mL/min e detecção a 260nm. Os resultados obtidos mostraram linearidade com coeficiente de correlação de 0,9995 para daidzeína, 0,9996 para genisteína, 0,9997 para formononetina e 0.9999 para biochanina A. A precisão e a exatidão apresentaram resultados satisfatórios. Boa resolução e rápida separação dos fármacos em formulações farmacêuticas também foram obtidas. Portanto, pode ser usado nas análises de rotina nos laboratórios de controle de qualidade de fitoterápicos. / Phytoestrogens are natural compounds of plants with estrogenic activity. They are being widely investigated in the prevention of chronic coronary diseases, in prostate and breast cancer, in the reduction of osteoporosis risk and relief of menopause symptoms. Among phytoestrogens already in use are daidzein, genistein and glycitein and they are present in complex matrix such as phytopharmaceuticals, plant extracts, capsules and tablets. These preparations require development and validation of methodologies for quantitative determination of isoflavones. The proposed methodologies include high performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC). The HPTLC coupled with densitometry can be used for quantitative analysis. The mobile phase constituted of ethyl acetate:hexane (8:2 v/v) was used to determine chromatographic profiles of isoflavone aglycones, daidzein, glycitein and genistein. The mobile phase constituted of ethyl acetate:toluene:formic acid (8:1:1 v/v/v) was used for determination of isoflavones glycosides and non-glycosides. For the quantitative determination of isoflavone glycosides with HPLC, an acid hydrolysis with 3M HCl and heating in water-bath for an hour was proposed as sample pretreatment step. The analytic determination of isoflavones daidzein, genistein, formononetin and biochanin A using HPLC was accomplished. The chromatography was carried out in isocratic mode with Chromolith®, a monolithic RP-18 column, (100x4.6mm) with mobile phase constituted of water:acetonitrile (6:4 v/v) operated at a flow rate of 0.6mL/min and detection was made at 260nm. The results showed method linearity with correlation coefficient of 0.9995 to daidzein, 0.9996 for genistein, 0.9997 for formononetin and 0.9999 for biochanin A. The precision and accuracy data presented satisfactory results. Good resolution and faster separation of compounds in pharmaceutical formulations were also obtained. The proposed method can be used in the routine analyses of phytopharmaceuticals in quality control laboratories.

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