<p>The novel method of this thesis work is based on using quadrature filters to estimate an orientation tensor and to use the advantage of tensor information to control 3D adaptive filters. The adaptive filters are applied to enhance the Magnetic Resonance Angiography (MRA) images. The tubular structures are extracted from the volume dataset by using the quadrature filters. The idea of developing adaptive filtering in this thesis work is to enhance the volume dataset and suppress the image noise. Then the output of the adaptive filtering can be a clean dataset for segmentation of blood vessel structures to get appropriate volume visualization.</p><p>The local tensors are used to create the control tensor which is used to control adaptive filters. By evaluation of the tensor eigenvalues combination, the local structures like tubular structures and stenosis structures are extracted from the dataset. The method has been evaluated with synthetic objects, which are vessel models (for segmentation), and onion like synthetic object (for enhancement). The experimental results are shown on clinical images to validate the proposed method as well.</p>

The novel method of this thesis work is based on using quadrature filters to estimate an orientation tensor and to use the advantage of tensor information to control 3D adaptive filters. The adaptive filters are applied to enhance the Magnetic Resonance Angiography (MRA) images. The tubular structures are extracted from the volume dataset by using the quadrature filters. The idea of developing adaptive filtering in this thesis work is to enhance the volume dataset and suppress the image noise. Then the output of the adaptive filtering can be a clean dataset for segmentation of blood vessel structures to get appropriate volume visualization. The local tensors are used to create the control tensor which is used to control adaptive filters. By evaluation of the tensor eigenvalues combination, the local structures like tubular structures and stenosis structures are extracted from the dataset. The method has been evaluated with synthetic objects, which are vessel models (for segmentation), and onion like synthetic object (for enhancement). The experimental results are shown on clinical images to validate the proposed method as well.

Twelve halloysites from different sources in Slovakia, Turkey, China, New Zealand and U.S.A. have been characterized by combination of analytical methods together with the commercial sample of halloysite supplied by Sigma-Aldrich. The aim of this work was to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. In nature, the formation of halloysite is related to the weathering of magmatic rocks or to the hydrothermal alteration of volcanic rocks, frequently in the contact with limestones. Halloysite belong to the kaolinite group, but, contrarily to kaolinite, it contains molecules of water in the interlayer space. It occurs in two forms: hydrated halloysite (10 ?) and dehydrated halloysite (7 ?).Dehydrated halloysites contain more admixtures than hydrated ones ? typically kaolinite, quartz, cristobalite, alunite, gibbsite and in one case also potassium mica. In samples containing both dehydrated halloysite and kaolinite their 001 diffractions overlap. Interaction with formamide was used in these cases to increase the interlayer space of halloysite and thus shift its basal diffraction to lower angles. The basal 001 diffraction of kaolinite after this treatment remains on 7 ?. Silver thiourea method (AgTU) was used to measure the cationic exchange capacity (CEC). Silver...

Orientador: Michael John Brennan / Resumo: A independência funcional para indivíduos com deficiência motora é indispensável para a qualidade de vida, principalmente quando se considera tarefas como o autocuidado (incluindo a higiene pessoal), as transferências e locomoção. Essa pesquisa apresenta um triciclo inovador para pessoas com paraplegia ou alguma deficiência motora dos membros inferiores, desenvolvido com duas forma de acionamento: cíclico manual (handbike) e elétrico. A estrutura tubular foi elaborada com liga de alumínio 6063 - T5. A plataforma ANSYS Academic versão 19.2 foi empregada para uma análise estrutural do chassi do equipamento. O chassi foi submetido num ensaio de carregamento estático progressivo de até 1200 N aproximadamente. O deslocamento onde apoia os pés do usuário foi medido por um relógio comparador de precisão de 0,01 mm. O deslocamento da plataforma inferior de apoio dos pés apresentou uma divergência de aproximadamente 4% se comparado com os dados obtidos pela plataforma ANSYS. Assim, validando a análise teórica pela plataforma ANSYS e confirmando que a estrutura fabricada por dobramento e solda TIG suporta com segurança um usuário de até 100 kg. Parâmetros relacionados ao sistema elétrico de acionamento do motor brushless de 1000 W foram obtidos por meio de sensores de corrente e voltagem, assim como parâmetros de desempenho mecânico foram obtidos empregando uma célula de carga de fundo de escala de 2kN para análise de força de tração e um sensor de velocidade. Os resultados indicam uma... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Functional independence for individuals with motor disabilities is essential for quality of life, especially when considering tasks such as self-care (including personal hygiene), transfers and locomotion. This research presents an innovative tricycle for people with motor deficiency of the lower limbs, developed with two forms of drive: manual cyclic (handbike) and electric. The tubular structure was made with 6063 - T5 aluminum alloy. The ANSYS Academic version 19.2 platform was used for a structural analysis of the equipment chassis. A static loading test of up to 1200 N was performed on the chassis. The deformation of support the user's feet was measured by a dial gauge with a 0,01 mm precision. The deformation of the lower footrest platform showed a divergence of approximately 4% when compared to the data obtained by the ANSYS platform. Thus, validating the theoretical analysis by the ANSYS platform and confirming that the structure manufactured by TIG welding safely supports a user of up to 100 kg. Parameters related to the electric drive system of the 1000 W brushless motor were obtained by means of current and voltage sensors, as well as mechanical performance parameters were obtained employing a load cell of 2kN for force analysis and a speed sensor. The results indicate an energy efficiency of the equipment of up to 92%. The maximum strength of the equipment is 500 N, which makes it possible to perform a climb with slope of 20º, approximately considering a user of 8... (Complete abstract click electronic access below) / Doutor

Dans les domaines de l’imagerie médicale et de la vision par ordinateur, la segmentation joue un rôle crucial dans le but d’extraire les composantes intéressantes d’une image ou d’une séquence d’images. Elle est à l’intermédiaire entre le traitement d’images de bas niveau et les applications cliniques et celles de la vision par ordinateur de haut niveau. Ces applications de haut niveau peuvent inclure le diagnostic, la planification de la thérapie, la détection et la reconnaissance d'objet, etc. Parmi les méthodes de segmentation existantes, les courbes géodésiques minimales possèdent des avantages théoriques et pratiques importants tels que le minimum global de l’énergie géodésique et la méthode bien connue de Fast Marching pour obtenir une solution numérique. Dans cette thèse, nous nous concentrons sur les méthodes géodésiques basées sur l’équation aux dérivées partielles, l’équation Eikonale, afin d’étudier des méthodes précises, rapides et robustes, pour l’extraction de structures tubulaires et la segmentation d’image, en développant diverses métriques géodésiques locales pour des applications cliniques et la segmentation d’images en général. / In the fields of medical imaging and computer vision, segmentation plays a crucial role with the goal of separating the interesting components from one image or a sequence of image frames. It bridges the gaps between the low-level image processing and high level clinical and computer vision applications. Among the existing segmentation methods, minimal geodesics have important theoretical and practical advantages such as the global minimum of the geodesic energy and the well-established fast marching method for numerical solution. In this thesis, we focus on the Eikonal partial differential equation based geodesic methods to investigate accurate, fast and robust tubular structure extraction and image segmentation methods, by developing various local geodesic metrics for types of clinical and segmentation tasks. This thesis aims to applying different geodesic metrics based on the Eikonal framework to solve different image segmentation problems especially for tubularity segmentation and region-based active contours models, by making use of more information from the image feature and prior clinical knowledges. The designed geodesic metrics basically take advantages of the geodesic orientation or anisotropy, the image feature consistency, the geodesic curvature and the geodesic asymmetry property to deal with various difficulties suffered by the classical minimal geodesic models and the active contours models. The main contributions of this thesis lie at the deep study of the various geodesic metrics and their applications in medical imaging and image segmentation. Experiments on medical images and nature images show the effectiveness of the presented contributions.