Nesse doutorado desenvolvemos um método para aumentar a precisão e sensibilidade das medidas de rotação não linear da polarização elíptica, RNLPE, usando um polarizador girante como analisador e um amplificador lock-in de fase dupla. Medidas de RNLPE são úteis na determinação da magnitude e sinal do índice de refração não linear, n2. Por se tratar de uma nova metodologia, confrontamos nossos resultados com resultados obtidos por varredura-Z, um método bem estabelecido e amplamente utilizado na determinação de n2. Com essa finalidade realizamos medidas de RNLPE e de varredura-Z em amostras com não linearidade eletrônica não ressonante, na condição de feixe fracamente focalizado. Os resultados obtidos comprovaram a equivalência entre as duas técnicas em termos de sensibilidade, precisão e simplicidade. Propusemos ainda uma configuração na qual múltiplas amostras são medidas simultaneamente em uma única varredura, condição de feixe fortemente focalizado. Esse método autorreferenciado permite melhor comparação entre os materiais já que o sinal de uma referência e da amostra em estudo são obtidos simultaneamente, sob as mesmas condições experimentais, além de permitir uma investigacão das não linearidades locais. Uma vez comprovado o potencial das medidas de RNLPE na condição de focalização forte passamos a estudar a contribuição de não linearidades não instantâneas pela medida de n2 em função da duração do pulso. Variando a duração do pulso estudamos não linearidades em amostras líquidas que possuem além da contribuição de efeito instantâneo eletrônico, efeitos nucleares não instantâneos como os de origem reorientacional lento. Um modelo empírico da dependência da não linearidade em função da duração do pulso foi proposto para explicar os resultados obtidos, no qual foi possível diferenciar as não linearidades instantâneas das não instantâneas e atribuir à última um tempo de resposta. / In this work we have developed a method to increase accuracy and sensitivity of the nonlinear rotation of elliptical polarization measurements by NER using a rotating polarizer as an analyzer and a dual-phase lock-in amplifier. NER measurements are useful in determining the magnitude and signal of the nonlinear refractive index, n2, of different materials. Because this is a new methodology, we compared our results with those obtained by Z-scan, a well-established and widely used method in determining n2. For this purpose we performed NER and Z-scan measurements on samples with pure non-resonant electronic nonlinearity, at weakly focused beam condition. The results obtained have shown the equivalence between both techniques in terms of sensitivity, precision and simplicity. We also proposed a configuration in which multiple samples are measured simultaneously in a single scan, at strongly focused beam condition. This self-referenced method allows better comparison between the materials since the signal of a reference and the sample under study are obtained simultaneously, under the same experimental conditions, besides allowing measuring the local nonlinearities. Once we verified the potential of NER measurements in the tightly focused condition we proceeded to study the contribution of non-instantaneous nonlinearities by measuring n2 as a function of the pulse duration. By varying the pulse duration we studied nonlinearities in liquid samples that have, besides the contribution of electronic instantaneous effect, contribution of non-instantaneous nuclear effects of slow orientational origin. An empirical model of the dependence of nonlinearity as a function of pulse duration was proposed to explain the results obtained, in which instantaneous nonlinearities and non-instantaneous nonlinearities could be discriminate and a response time to the latter could be assigned.

The aim of this project is to design an algorithm that identifies the Area of Interest (AOI) in ELISpot and FluoroSpot images. ELISpot and FluoroSpot are two varieties of a biochemical test used to analyze immune responses by quantifying the amount of cytokine secreted by cells. ELISpot and FluoroSpot images show a well that contains the cytokinesecreting cells which appear as scattered spots. Prior to counting the number of spots, it is required to detect the area in which to count the spots, i.e. the area delimited by the contour of the well. We propose to use the Circle Hough Transform together with filtering and the Laplacian of Gaussian edge detector in order to accurately detect such area. Furthermore we develop an outlier removal method that contributes to increase the robustness of the proposed detection method. Finally we compare our algorithm with another algorithm already in use. A Swedish biotech company called Mabtech has implemented an AOI identifier in the same field. Our proposed algorithm proves to be more robust and provides consistent results for all the images in the dataset.

Cette thèse porte sur différentes problématiques liées à la détection, l'ajustement et l'identification de structures elliptiques en images. Nous plaçons la détection de primitives géométriques dans le cadre statistique des méthodes a contrario afin d'obtenir un détecteur de segments de droites et d'arcs circulaires/elliptiques sans paramètres et capable de contrôler le nombre de fausses détections. Pour améliorer la précision des primitives détectées, une technique analytique simple d'ajustement de coniques est proposée ; elle combine la distance algébrique et l'orientation du gradient. L'identification d'une configuration de cercles coplanaires en images par une signature discriminante demande normalement la rectification Euclidienne du plan contenant les cercles. Nous proposons une technique efficace de calcul de la signature qui s'affranchit de l'étape de rectification ; elle est fondée exclusivement sur des propriétés invariantes du plan projectif, devenant elle même projectivement invariante / This thesis deals with different aspects concerning the detection, fitting, and identification of elliptical features in digital images. We put the geometric feature detection in the a contrario statistical framework in order to obtain a combined parameter-free line segment, circular/elliptical arc detector, which controls the number of false detections. To improve the accuracy of the detected features, especially in cases of occluded circles/ellipses, a simple closed-form technique for conic fitting is introduced, which merges efficiently the algebraic distance with the gradient orientation. Identifying a configuration of coplanar circles in images through a discriminant signature usually requires the Euclidean reconstruction of the plane containing the circles. We propose an efficient signature computation method that bypasses the Euclidean reconstruction; it relies exclusively on invariant properties of the projective plane, being thus itself invariant under perspective

Diese Arbeit befaßt sich mit der SAW-STM-Methode, einer Abwandlung der Rastertunnelmikroskopie (engl. scanning tunneling microscopy) zur hochauflösenden Abbildung akustischer Oberflächenwellen (engl. surface acoustic wave). Das Meßprinzip des SAW-STM beruht auf der Modulation des Tunnelabstandes und der hieraus resultierenden Modulation des Tunnelstroms durch die oszillatorische Bewegung der Probenoberfläche. Zur einfacheren Signaldetektion wird ein Heterodyn-Verfahren verwendet, das über eine zusätzliche Modulation der Tunnelspannung das SAW-STM Signal in den kHz-Frequenzbereich verschiebt. Dieses trägt die komplette Information über die Amplitude und die Phase der Tunnelabstandsmodulation. Im Rahmen dieser Arbeit wird die Abhängigkeit des SAW-STM Signals von den experimentellen Paramtern und von der Topographie der Probe theoretisch beschrieben und experimentell untersucht. Dies führt zu einer kalibrierten Vermessung der oszillatorischen Bewegungsbahn der SAW-tragenden Probenoberfläche. Das untersuchte Materialsystem ist ein 40 nm dicker Goldfilm auf einem LiNbO3-Substrat im Y-Schnitt, das eine Welle vom Rayleigh-Typ in Z-Richtung trägt. Indem ein SAW-STM entwickelt wird, das im Ultrahochvakuum (UHV) arbeitet, wird die SAW-STM Methode hinsichtlich des Spektrums untersuchbarer reaktiver Materialien und hinsichtlich der Signalstabilität. Es wird der Umbau eines kommerziellen Rastertunnelmikroskops zum SAW-STM beschrieben. Zu diesem Zweck wird eine Probenhalterung konstruiert, die den Transfer der Probe zwischen der Bedampfungseinrichtung und dem STM ohne Belüftung der Kammer erlaubt. Gleichzeitig stellt sie automatisch die fünf notwendigen elektrischen Kontakte zum Probenchip her, wenn die Probenhalterung in das STM gesetzt wird. Weiterhin werden die Konstruktion eines UHV-tauglichen Sytems von Hochfrequenz-Signalleitungen und der Bedampfungseinrichtung zur in-situ Probenpräparation beschrieben. Mit diesem UHV-SAW-STM können SAWs einer Amplitude im Bereich von 0.001 Å bis 1 Å angeregt und detektiert werden. Die maximale Frequenz, die eine im UHV-SAW-STM nachweisbare SAW haben kann, beträgt mindestens 360 MHz. Weiterhin wird das in LabVIEW geschriebenen Softwarepacket zur Auswertung der SAW-STM-Daten vorgestellt. Um die SAW-STM-Methode auf ein sicheres Fundament zu stellen, wurde erstmals systematisch die Abhängigkeit des SAW-STM-Signals von den Meßparametern experimentell untersucht. Die im Rahmen dieser Arbeit entwickelte Theorie des SAW-STM-Signals beschreibt die experimenell gefundenen Abhängigkeiten hinreichend gut. Zentraler Punkt dieser Theorie ist dabei die Berücksichtigung der Abstandsregelung des STM, die im Constant-Current-Modus die Spitzenposition so regelt, daß der mittlere Tunnelstrom konstant ist. Der Vergleich der gemessenen und der theoretischen Abhängigkeit der Signalamplitude von der Amplitude der Modulation des Tunnelabstandes ermöglicht dabei die kalibrierte Messung der Amplitude der vertikale Auslenkung der Rayleighwelle. Scans der SAW-STM-Methode liefern Bilder der Topographie sowie der Amplitude und der Phase des SAW-STM-Signals. Mit der Theorie des SAW-STM-Signal der korrugierten Probenoberfläche werden aus der gemessenen Topographie simulierte Amplituden- und Phasebilder erstellt und mit den gemessenen Bildern verglichen. Während die Übereinstimmung mit den gemessenen Amplitudenbildern nur qualitativer Art ist, erlaubt der quantitative Vergleich zwischen simulierten und gemessenen Phasenbildern die Bestimmung der Exzentrizität der Oszillationsellipse. Zusammen mit der oben erläuterten Messung der vertikalen Auslenkungsamplitude ist somit in dieser Arbeit die Oszillationsellipse der Rayleighwelle vollständig ausgemessen. / This thesis deals with the SAW-STM method, which is a technique based on scanning tunneling microscopy (STM) for the high-resolution mapping of surface acoustic waves (SAW). The measurement principle of the SAW-STM utilizes the modulation of the tunneling distance and the resulting modulation of the tunneling current due to the mechanic oscillation of the sample surface. To facilitate signal detection a heterodyn technique is employed which shifts the measured signal into the kHz-range by adding modulation to the tunneling voltage. The signal contains the entire information about the amplitude and the phase of the SAW-induced tunneling distance modulation. Experiments are presented to investigate the dependence of the signal amplitude on the experimental parameters and on the sample topography. This data is compared to a theory developed to describe the SAW-STM signal, leading to a calibrated measurement of the trajectory of the sample surface which carries the wave. The sample we investigated was a 40 nm gold film deposited on a LiNbO3 substrate in the Y-cut, deformed by a Rayleigh-type wave in the z-direction. To increase signal stability and to extend the range of reactive sample materials we constructed a SAW-STM operating in the ultra-high-vacuum (UHV). In this thesis the conversion of a commercial STM to a SAW-STM is described. A sample holder is constructed, which allows the transfer of the sample between the evaporation stage and the STM without venting the UHV chamber. It provides a contact spring mechanism for the automatical electric contactation of the sample chip, when the sample holder is inserted into the STM. Moreover, we installed a UHV-compatible wiring system for SAW-excitation and for signal detecting and an evaporation stage for in-situ sample preparation. We demonstrate that the UHV-SAW-STM is capable of exiting and detecting surface acoustic waves with an amplitude in the range 0.001 Å to 1 Å. The maximal frequency of SAW which can be studied with the UHV-SAW-STM is found to be at least 360 MHz. For the analysis of SAW-STM data a LabVIEW software package was implemented. To put the SAW-STM technique on a strong basis, we systematically studies the dependence of the SAW-STM signal on the various measurement parameters. The theory of the SAW-STM signal developed in this work is in good agreement with this experimental data. In this theory, we take into account that the STM is operated in the constant-current mode, i.e. the tip position is controlled to keep the average tunneling current constant. The comparison of the measured and the simulated dependence of the signal amplitude on the amplitude of the tunneling distance modulation allows the calibrated measurement of the vertical displacement amplitude of the Rayleigh wave. SAW-STM scans yield images of the topography and of the amplitude and the phase of the SAW-STM signal. Employing the theory of the SAW-STM signal on the corrugated surface, we simulated amplitude and phase imaged based on the measured topography. The agreement between simulated and measured amplitude images is only qualitative. In contrast, the comparison of simulated and measured phase images allows the determination of the excentricity of the oscillation ellipse. Having determined this excentricity and the vertical displacement amplitude of the Rayleigh wave, we have gaind complete knowledge about the geometry of the Rayleigh wave oscillation ellipse.

O presente trabalho destina-se ao estudo numérico da geometria de tubos de seção elíptica que facilite a transferência de calor adimensional e diminua a queda de pressão adimensional (Δ̃) sofrida pelo escoamento. O método aplicado é o Design Construtal, que visa determinar a geometria que apresentará a menor resistência ao escoamento, ou seja, busca-se determinar a razão de aspecto da elipse (=⁄) que favorece a transferência de calor e diminui a queda de pressão do escoamento. O fluido empregado neste estudo apresenta características de viscoplasticidade. A relação entre a tensão cisalhante e a taxa de deformação obedece ao modelo de Herschel-Bulkley modificado. Considera-se que o escoamento é incompressível, laminar, bidimensional, externo e ocorre em regime permanente. A solução numérica do problema proposto é realizada com um código comercial baseado no método dos volumes finitos. É investigada a influência do índice de potência, , sobre a seção elíptica que facilita o escoamento e, para isso, este índice é variado de 0,4 a 1. A influência dos números de Reynolds (√), Herschel-Bulkley (√) e Prandtl (√) sobre o comportamento do escoamento também é avaliada. √ é variado de 1 a 40, √ é variado de 1 a 100 e √ é variado de 0,1 a 100 Os resultados mostram que, para um escoamento com √=1, √=1 e √=1, o aumento do índice de potência influencia negativamente na transferência de calor adimensional e a seção elíptica, que maximiza esta transferência de calor adimensional, tende a ser mais alongada na direção do escoamento. Já e influenciam positivamente na transferência de calor adimensional. Para um escoamento com √=1, √=1, =0,4 conclui-se que com o aumento de a razão de aspecto ótima (q,opt), do ponto de vista térmico, diminui. Quando é considerado um escoamento com √=1, √=1, =0,4 conclui-se que q,opt diminui com o aumento de , ou seja, a elipse torna-se mais alongada no sentido do escoamento. A variação de √ em um escoamento com √=1, √=1, =0,4 mostra que o aumento deste parâmetro acarreta em aumento da taxa de transferência adimensional e de Δ̃. / The present work is aimed at the numerical study of the geometry of elliptic section tubes that facilitates the dimensionless heat transfer and decreases the dimensionless pressure drop (Δ̃) suffered by the flow. The applied method is the Construtal Design, which aims to determine the geometry that will present the least resistance to the flow, that is, to determine the aspect ratio of the ellipse (=⁄) that favors heat transfer and decreases the flow pressure drop. The fluid used in this study has viscoplasticity characteristics. The relationship between shear stress and strain rate follows the modified Herschel-Bulkley model. It is considered that the flow is incompressible, laminar, two-dimensional, external and occurs in steady state. The numerical solution of the proposed problem is carried out with a commercial code based on the finite volume method. The influence of the power index, n, on the elliptical section facilitating the flow is investigated, and for this, the index is varied from 0.4 to 1. The influence of the Reynolds number (√), Herschel-Bulkley number (√) and Prandtl number (√) on the flow behavior is also evaluated √ is varied from 1 to 40, √ is varied from 1 to 100 and √ is varied from 0.1 to 100. The results show that for a flow with √=1, √=1 and √=1, the increase of the power index negatively influences the dimensionless heat transfer and the elliptic section, which maximizes this dimensionless heat transfer, tends to be more elongated in the direction of flow. Already √ and √ influence positively the dimensionless heat transfer. For a flow with √=1, √=1, =0.4 it is concluded that with the increase of √ the optimum aspect ratio (q,opt), from the thermal point of view, decreases. When a flow is considered with √=1, √=1, =0.4 it is concluded that q,opt decreases with the increase of √, that is, ellipse becomes more elongated in the flow direction. The variation of √ in a flow with √=1, √=1, =0.4 shows that the increase of this parameter causes an increase of the dimensionless transfer rate and Δ̃.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-10T14:58:57Z No. of bitstreams: 2 Dissertação - Pollyana Gomes Volpato - 2016.pdf: 1172027 bytes, checksum: 6e8ebfc67549380e690db90bc68b9104 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-11T09:42:09Z (GMT) No. of bitstreams: 2 Dissertação - Pollyana Gomes Volpato - 2016.pdf: 1172027 bytes, checksum: 6e8ebfc67549380e690db90bc68b9104 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-11T09:42:09Z (GMT). No. of bitstreams: 2 Dissertação - Pollyana Gomes Volpato - 2016.pdf: 1172027 bytes, checksum: 6e8ebfc67549380e690db90bc68b9104 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-09 / The main objective of this work is to demonstrate Marden’s Theorem, which tells us that given a third-degree polynomial with complex coefficients, the roots of this polynomial are not collinear and form a triangle T in the complex plane. There is a unique ellipse inscribed in T and tangent to the sides at their midpoints. The foci of this ellipse are the roots of the derivative of the polynomial. We show that such an ellipse is Steiner’s Ellipse. We make a generalization of the Marden Theorem using degree n polynomial. / Temos como objetivo central neste trabalho demonstrar o Teorema de Marden, que nos diz que, dado um polinômio de terceiro grau com coeficientes complexos, as raízes desse polinômio não são colineares e formam um triângulo T no plano complexo. Há uma única elipse inscrita em T e tangente aos lados nos seus pontos médios. Os focos dessa elipse são as raízes da derivada do polinômio. Mostramos que tal elipse é a Elipse de Steiner. Fazemos uma generalização do Teorema de Marden utilizando polinômio de grau n.

In this study a fully automatic and scale invariant feature extractor which does not require manual initialization or special equipment is proposed. Face location and size is extracted using skin segmentation and ellipse fitting. Extracted face region is scaled to a predefined size, later upper and lower facial templates are used for feature extraction. Template localization and template parameter calculations are carried out using Principal Component Analysis. Changes in facial feature coordinates between analyzed image and neutral expression image are used for expression classification. Performances of different classifiers are evaluated. Performance of proposed feature extractor is also tested on sample video sequences. Facial features are extracted in the first frame and KLT tracker is used for tracking the extracted features. Lost features are detected using face geometry rules and they are relocated using feature extractor. As an alternative to feature based technique an available holistic method which analyses face without partitioning is implemented. Face images are filtered using Gabor filters tuned to different scales and orientations. Filtered images are combined to form Gabor jets. Dimensionality of Gabor jets is decreased using Principal Component Analysis. Performances of different classifiers on low dimensional Gabor jets are compared. Feature based and holistic classifier performances are compared using JAFFE and AF facial expression databases.

Zur schnellen und sicheren Gepäckabfertigung ist eine Automatisierung der Gepäckprüfung zweckmäßig. Es wird eine mehrstufige Prüfung des Gepäcks durchgeführt. In der ersten Stufe werden vom Gepäckstück mehrere Röntgendurchstrahlungbilder angefertigt. Bei einem Teil der Gepäckstücke wird ein kritischer Bereich festgestellt, welcher mit einer zweiten Maschine genauer untersucht werden muss. Aus diesem Grund muss durch die zweite Maschine anhand nur eines weiteren Röntgendurchstrahlungsbildes erkannt werden, wo sich der kritische Bereich nach dem Transport durch das Förderband befindet. Zur Lösung dieses als Positionswiederfindung bezeichneten Problems wurde ein Verfahren entwickelt, welches auf einer Beziehung zwischen den Momenten der Grauwertverteilung des Durchstrahlungsbildes und den Momenten der Schwächungskoeffizentenverteilung des Objektes beruht. Das Verfahren wurde anhand von simulierten Beispielen getestet. / Automatic explosive detection is advantageous for fast and secure baggage control. The baggage is controlled by a multi level system. In level 1 the baggage will be inspected by a multi view x-ray radiography machine. The machine divides the baggage into secure and rejected bags and finds in the rejected bags a critical region for further inspection by a level 2 machine. For this reason the level 2 machine has to identify by only one additional x-ray view the new position of the critical region of the bag after the transport to the level 2 machine. To solve this problem a method was developed, which uses a relation between the moments of the grey-value of x-ray scan and the moments of the x-ray attenuation coefficient of the inspected object. The method was tested with simulated scans.

Steered Response Power based algorithms are widely used for finding sound source location using microphone array systems. SRCP-PHAT is one such algorithm that has a robust performance under noisy and reverberant conditions. The algorithm creates a likelihood function over the field of view. This thesis employs image processing methods on SRCP-PHAT images, to exploit the difference in power levels and pixel patterns to discriminate between sound source and background pixels. Hough Transform based ellipse detection is used to identify the sound source locations by finding the centers of elliptical edge pixel regions typical of source patterns. Monte Carlo simulations of an eight microphone perimeter array with single and multiple sound sources are used to simulate the test environment and area under receiver operating characteristic (ROCA) curve is used to analyze the algorithm performance. Performance was compared to a simpler algorithm involving Canny edge detection and image averaging and an algorithms based simply on the magnitude of local maxima in the SRCP image. Analysis shows that Canny edge detection based method performed better in the presence of coherent noise sources.

Chez Guillevic, le statut de la rhétorique est paradoxal. Toute l'œuvre est traversée par un impératif des choses et du réel qui s'accompagne d'un vœu de simplicité. Cette poésie, qui se voit rappelée à l'ordre du concret, se méfie d'une rhétorique qui viendrait éclipser la réalité des choses, ou accroître la distance entre ces deux pôles, que sont l'expérience du monde et sa mise en mots. Les poèmes, denses et resserrés sur eux-mêmes, se présentent alors manifestement comme un défi à la rhétorique. Pourtant, nous n'assistons pas à une éviction de la notion, mais plutôt à un ensemble de mutations, qui supposent une subrogation des valeurs la définissant. En effet, si Guillevic passe pour un poète qui se serait spontanément tourné vers le monde et vers les objets, ce rapport au réel, au départ, n'a rien d'euphorique. Il reste à construire car le monde se rétracte. Il faut retrouver une force dans le langage ; une force agissante. Se méfier d'une rhétorique éloquente et ornementale revient alors à inscrire dans le poème une tension qui fait du langage un support solide auquel se raccrocher ; les figures ne sont plus de l'ordre de la figuration mais de celui de la mise en rapport. On assiste donc à des processus de relittéralisation et de défiguration du langage, ce qui fait qu'il n'est plus question d'une rhétorique de surface, mais d'une rhétorique fondamentale, qui passe par un engagement de l'être dans le langage. Et comme il s'agit toujours de chercher à faire l'expérience du monde, plutôt que de s'obstiner à lui trouver un sens, la rhétorique est alors dissociée de ces notions de conceptualité, de représentation et de signification qu'elle a tendance à véhiculer. Enfin, chez Guillevic, se méfier de la rhétorique, c'est aussi remplacer la métaphore par l'ellipse et instaurer dans le poème un creux, ou un entre-deux, qui, sans pour autant annuler ce constat d'une inadéquation fondamentale entre le langage et la réalité, ne se présente pas moins comme le lieu où peut advenir une dimension neuve et originelle du sujet, du langage et du monde.