21 resultados para Image acquisition and representation


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Dissertation presented to obtain the degree of Doctor of Philosophy in Electrical Engineering, speciality on Perceptional Systems, by the Universidade Nova de Lisboa, Faculty of Sciences and Technology

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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Since the invention of photography humans have been using images to capture, store and analyse the act that they are interested in. With the developments in this field, assisted by better computers, it is possible to use image processing technology as an accurate method of analysis and measurement. Image processing's principal qualities are flexibility, adaptability and the ability to easily and quickly process a large amount of information. Successful examples of applications can be seen in several areas of human life, such as biomedical, industry, surveillance, military and mapping. This is so true that there are several Nobel prizes related to imaging. The accurate measurement of deformations, displacements, strain fields and surface defects are challenging in many material tests in Civil Engineering because traditionally these measurements require complex and expensive equipment, plus time consuming calibration. Image processing can be an inexpensive and effective tool for load displacement measurements. Using an adequate image acquisition system and taking advantage of the computation power of modern computers it is possible to accurately measure very small displacements with high precision. On the market there are already several commercial software packages. However they are commercialized at high cost. In this work block-matching algorithms will be used in order to compare the results from image processing with the data obtained with physical transducers during laboratory load tests. In order to test the proposed solutions several load tests were carried out in partnership with researchers from the Civil Engineering Department at Universidade Nova de Lisboa (UNL).

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Proceedings of the Sixth Portuguese Conference on Bioemedical Engineering faro, Portugal

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RESUMO - A preocupação com os conhecimentos, atitudes, crenças e práticas, no que concerne à utilização de radiações ionizantes para fins de diagnóstico, e a sensibilização de todos os agentes envolvidos, médicos, técnicos, físicos, utentes e responsáveis pela Saúde Publica, relativamente aos níveis de radiação emitida nos exames de Tomografia Computorizada (TC), assume particular importância no domínio da Saúde Pública, na medida em que é necessário influenciar o desenvolvimento de práticas que promovam, auditem e garantam a prestação do controlo da qualidade radiológica e dosimétrica nos serviços de Radiologia a nível Nacional. Para tal, e no âmbito da publicação de estudos já realizados ao nível da União Europeia, ―Orientações Europeias dos Critérios de Qualidade para a Tomografia Computorizada (1999) ‖, é proposto estabelecer orientações na realização de estudos que permitam, numa primeira fase, estabelecer a comparação com os resultados obtidos pelos mecanismos de Controlo da Qualidade (CQ), analisar e proceder aos ajustes (se necessário) e, numa segunda fase, implementar uma moldura sistemática de avaliação periódica dos níveis de dose de radiação por exame TC e que permita a monitorização dos dados. Nesse sentido, propõe-se a realização de um Estudo Nacional que envolva a rede hospitalar pública, privada e universitária, partindo da metodologia utilizada em estudos prévios noutros países da Europa, como seja, selecção do equipamento de TC existente na Instituição Hospitalar, onde serão reunidas informações através do preenchimento de questionários relativos ao equipamento a utilizar. Serão recolhidos dados relativos ao utente, ao equipamento e parâmetros de aquisição de imagem, que permitam identificar os níveis de referência de diagnóstico (NRD) em TC, na realidade Portuguesa. Foi efectuado um estudo piloto numa instituição EPE e os valores obtidos não são significativos, nem podem assumir valor preditivo dado o reduzido tamanho da amostra. Apesar disso, sugerem a existência de parâmetros que podem ser alterados e com isso podem fazer variar a dose de radiação utilizada. ENSP/UNL Maria de Fátima Vaz de Carvalho 5 Espera-se obter com este estudo, como foi referido, a base do estabelecimento dos NRD em TC em Portugal. ----------------- ABSTRACT - The purpose of this study, in an empirical point of view, emerges from concern with the knowledge, attitudes, beliefs and practices regarding the use of ionizing radiation for diagnostic purposes and awareness of all actors involved, medical physical, technical, and responsible public health for the development of practices that promote, audited and ensure the provision of radiological quality control and dosing in radiology service at national level. In view of the complexity and characteristics involved in relation to ionizing radiation, all assume their part in protecting the physical integrity of each user and a global perspective, to ensure the safeguarding of public health, while global and globalizing factor. To this end, and in the context of the publication of studies already carried out at European Union level, "European guidelines for quality criteria for computed tomography", it is proposed to establish guidelines in conducting studies to initially establish the comparison with the results obtained by QC and make adjustments if necessary, and subsequently implement a systematic periodic assessment frame that allows monitoring of data. Accordingly, it is proposed to conduct a national study involving the public network, private and University hospitals, that extends from the methodology used in previous studies in other countries of Europe, as is, selection of equipment of existing CT in Hospital Institution, where information will be gathered by filling out questionnaires concerning the equipment to be used. Data will be collected for the wearer, equipment and parameters of image acquisition, identifying diagnostic reference levels (NRD) in CT in Portuguese fact. A pilot study was carried out in an institution EPE and the values obtained are not significant, nor can they take predictive value given the small sample size. Despite this, suggest the existence of parameters that can be changed and this can vary the dose of radiation used It is hoped to get with this study, as mentioned, the basis of the establishment of NRD in CT in Portugal.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics

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Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

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Dissertação para obtenção do grau de Mestre em Engenharia Química e Bioquímica