In this dissertation, imaging characteristics of a nano-slit are investigated. Applications of a scanning and rotating nano-slit in measuring sub-micron aerial features are demonstrated. Coherent sub-micron spot distributions are reconstructed with a very high contrast. Finally, high NA partially coherent images with features as small as 210 nm half-pitch are reconstructed and the ultimate resolution of the system is determined.A nano-slit is characterized as a sensor for coherent line-and-space features. Experiments and simulation verify image detection with contrasts greater than 0.9. Effects of polarization on imaging performance are reported. A scanning and rotating nano-slit in conjunction with a filtered back-projection technique is used to reconstruct sub-micron coherent spot distributions. Simulation results show very good agreement with the experiment. Further, it is shown that the reconstruction is very resilient to some common random experimental errors.Imaging characteristics of a scanning nano-slit sensor are determined for high NA partially coherent images. Good imaging performance (contrast > 0.8) is demonstrated with line-and-space images up to a spatial frequency of 2.38 lp / micron. Sub-micron features in a high NA partially coherent image are measured with a scanning and rotating nano-slit. A modified microscope is used to create the measured features, including 210 nm half-pitch features that cannot be imaged using the microscope in a conventional imaging mode. Using the filtered back projection technique, two-dimensional sub-micron features are reconstructed by the nano-slit sensor. It is determined that the resolution limit of ~ 200 nm is determined by the reconstruction technique and not by the width of the nano-slit.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / In this paper, we present the recent results of theoretical development and software implementation of a complete collection of high-performance image reconstruction algorithms designed for high-resolution imaging for various data acquisition configurations.

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Gossamer membranes are large, ultra light weight, highly flexible thin films. They have been proposed for use as elements in systems such as solar sails and optical apertures, whose large areas require a low-mass material that can be launched in a compact package and then deployed to operational configuration upon reaching orbit. Many of the proposed applications require that the film possess a flat, wrinkle-free surface. Surface wrinkle configuration is determined, in part, by the method used to support the film. One configuration that has not been studied in detail involves the formation of vertical wrinkles oriented along the direction of a tensile force applied at the upper and lower horizontal film supports. An experiment was designed to allow known forces to be applied to a 9 inch by 9 inch square sample of film supported at its upper and lower boundaries. Four films 7.6 m and 12.7 m thick samples of Kapton (polymide), and 12.2 m and 23.4 m thick samples of Mylar were loaded at levels of applied tensile force ranging from 1.446 to 4.388 N. The out-of-plane surface contours that resulted were measured using close-range photogrammetry, a non-contact, optical measurement technique. Experimental results indicate that both wrinkle wavelength and amplitude decrease as a function of applied force magnitude. These trends matched those obtained using numerical techniques, which also showed that lateral border strain, not measured during the experiment, may be a more important factor in determining surface wrinkle configuration. After presentation of the results, the photogrammetry technique is further considered as a tool for use in the manufacturing industry, in similar close-range applications, for the measurement of both dimensions and displacements.

Thesis (M.E.)--University of Canterbury, 2007. / Typescript (photocopy). "February 2007." Includes bibliographical references (p. [85]-88). Also available via the World Wide Web.

[pt] A presente tese analisa o problema da redução de ganho entre aberturas circulares situadas em região de Fresnel, tendo como objetivo a determinação do fator de correção a ser introduzido nas medidas de ganho em campo próximo. Para duas diferentes famílias de iluminação nas aberturas, são apresentados um conjunto de tabelas para o fator de redução de ganho bem côo suas curvas correspondentes. / [en] The following work analyzes the problem of gain reduction between circular apertures located in the Fresnel region, and aims to determine the correction factor to be applied when measuring near field gains. Two different sets of aperture illumination forms are presented, for which sets of tables of the reduction factor as well as the corresponding curves have been developd.

No description available.

Le traitement médical des allergies nécessite la caractérisation des pollens en suspension dans l’air. Toutefois, cette tâche requiert des temps d’analyse très longs lorsqu’elle est réalisée de manière manuelle. Une approche automatique améliorerait ainsi considérablement les applications potentielles du comptage de pollens. Les dernières techniques d’analyse d’images permettent la détection de caractéristiques discriminantes. C’est pourquoi nous proposons dans cette thèse un ensemble de caractéristiques pertinentes issues d’images pour la reconnaissance des principales classes de pollen allergènes. Le cœur de notre étude est l’évaluation de groupes de caractéristiques capables de décrire correctement les pollens en termes de forme, texture, taille et ouverture. Les caractéristiques sont extraites d’images acquises classiquement sous microscope, permettant la reproductibilité de la méthode. Une étape de sélection des caractéristiques est appliquée à chaque groupe pour évaluer sa pertinence.Concernant les apertures présentes sur certains pollens, une méthode adaptative de détection, localisation et comptage pour différentes classes de pollens avec des apparences variées est proposée. La description des apertures se base sur une stratégie de type Sac-de-Mots appliquée à des primitives issues des images. Une carte de confiance est construite à partir de la confiance donnée à la classification des régions de l’image échantillonnée. De cette carte sont extraites des caractéristiques propres aux apertures, permettant leur comptage. La méthode est conçue pour être étendue de façon modulable à de nouveaux types d’apertures en utilisant le même algorithme mais avec un classifieur spécifique.Les groupes de caractéristiques ont été testés individuellement et conjointement sur les classes de pollens les plus répandues en Allemagne. Nous avons montré leur efficacité lors d’une classification de type SVM, notamment en surpassant la variance intra-classe et la similarité inter-classe. Les résultats obtenus en utilisant conjointement tous les groupes de caractéristiques ont abouti à une précision de 98,2 %, comparable à l’état de l’art. / The correct classification of airborne pollen is relevant for medical treatment of allergies, and the regular manual process is costly and time consuming. An automatic processing would increase considerably the potential of pollen counting. Modern computer vision techniques enable the detection of discriminant pollen characteristics. In this thesis, a set of relevant image-based features for the recognition of top allergenic pollen taxa is proposed and analyzed. The foundation of our proposal is the evaluation of groups of features that can properly describe pollen in terms of shape, texture, size and apertures. The features are extracted on typical brightfield microscope images that enable the easy reproducibility of the method. A process of feature selection is applied to each group for the determination of relevance.Regarding apertures, a flexible method for detection, localization and counting of apertures of different pollen taxa with varying appearances is proposed. Aperture description is based on primitive images following the Bag-of-Words strategy. A confidence map is built from the classification confidence of sampled regions. From this map, aperture features are extracted, which include the count of apertures. The method is designed to be extended modularly to new aperture types employing the same algorithm to build individual classifiers.The feature groups are tested individually and jointly on of the most allergenic pollen taxa in Germany. They demonstrated to overcome the intra-class variance and inter-class similarity in a SVM classification scheme. The global joint test led to accuracy of 98.2%, comparable to the state-of-the-art procedures.

This thesis proposes a metallic hole array of a rectangular converging-diverging channel (RCDC) shape with extraordinary transmission. We use a three-dimensional (3D) finite element method to analyze the transmission characteristics of two-dimensional metallic hole arrays (2D-MHA) with RCDC. For a straight channel MHA, when the aperture size is reduced, the transmission peaks have a blue-shift. The same result is observed for a smaller gap throat for the RCDC structure. For the rectangular holes with a high length-width ratio, a similar blue-shift in the transmission peaks as well as a narrower full width at half maximum (FWHM) are observed. The asymmetry from the rectangular shape gives this structure high selectivity for light with different polarizations. Furthermore, the RCDC shape gives extra degrees of geometrical variables to 2D-MHA for tuning the location of the transmission peak and FWHM. The tunable transmission property of this structure shows promise for applications in tunable filters, photonic circuits, and biosensors. / text

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