964 resultados para Imagens digitais


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Pós-graduação em Biologia Geral e Aplicada - IBB

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Pós-graduação em Ciência da Computação - IBILCE

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The biometric characteristics have been used increasingly as a way to identify an individual, mainly for security reasons. Among them, the fingerprint is the most used biometric characteristic around the world, because it is relatively simple and very efficient. In this scene, there was a significant increase in the size of databases containing information on fingerprints, necessary to perform the recognition of a person. The task of classifying them beforehand has become extremely important as it reduces dramatically the size of the problem during a search, because it is not necessary to go through the whole database. Considering its importance, in the last thirty years, many techniques have been developed to try to increase the efficiency of the classification process. This project followed the rules-based approach and the Software Development Kit (SDK) VeriFinger 6.1 was used to assist in the detection of cores and deltas. Additionally, the classification was also implemented by means of directional map and the Poincar´e index. To make the experiments, the number four database from the National Institute of Standards and Technology (NIST) was used, which is a standard in this area

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The use of physical characteristics for human identification is known as biometrics. Among the many biometrics traits available, the fingerprint is the most widely used. The fingerprint identification is based on the impression patterns, as the pattern of ridges and minutiae, characteristics of first and second levels respectively. The current identification systems use these two levels of fingerprint features due to the low cost of the sensors. However, the recent advances in sensor technology, became possible to use third level features present within the ridges, such as the perspiration pores. Recent studies show that the use of third-level features can increase security and fraud protection in biometric systems, since they are difficult to reproduce. In addition, recent researches have also focused on multibiometrics recognition due to its many advantages. The goal of this research project was to apply fusion techniques for fingerprint recognition in order to combine minutia, ridges and pore-based methods and, thus, provide more robust biometrics recognition systems, and also to develop an automated fingerprint identification system using these three methods of recognition. We evaluated isotropic-based and adaptive-based automatic pore extraction methods, and the fusion of pore-based method with the identification methods based on minutiae and ridges. The experiments were performed on the public database PolyUHRF and showed a reduction of approximately 16% in the EER compared to the best results obtained by the methods individually

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this study was to assess if the positioning of the impression tray could cause plaster casts distortion during gypsum setting time. fifteen pairs of master models were cast with alginate impression material and immediately poured with gypsum. impressions were allowed to set with the tray in the not inverted position (group a) or in the inverted position (group b). the plaster models were digitized using a laser scanner (3shape r-700, 3shape a/s). tooth size measurements and distances were obtained using o3d software (widialabs, brasil) measurement tools. data were analyzed by paired t test and linear regression with 5% significance. most measurements of both groups were similar, except for the lower intermolar distance. it was not possible to corroborate the presence of distortions owing to the position of the impression tray during gypsum setting time.

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The aim of this study was to evaluate whether digitized images obtained from periapical radiographs taken with low dose of radiation could be improved with the aid of a computer software (PhotoStyler) for digital treatrnent. Serial and standardized radiographs of molar and premolar areas were studied. A total of 57 images equivalent to the radiographs taken with reduced exposure time ( 60 and 80% of the time considered normal), digitized and treated, were submitted to the evaluation of seven exanúners which compared them with those images without treatment. lt was verified that about 80% of the images equivalem to lhe radiographs taken with 60% reduction of ordinary exposure time were considered to having quality for supporting diagnosis. As for the images taken with 80% reduction of ordinary exposure time, about 50% of them were considered suitable for the sarne purpose

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Pós-graduação em Televisão Digital: Informação e Conhecimento - FAAC

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Cinco anos após o início das transmissões da TV Digital no Brasil, faltando próximo há três anos para o desligamento da transmissão analógica, observou-se o empenho das emissoras e da indústria de equipamentos para televisão, no que tange a substituição da atual tecnologia de produção, registro, edição e exibição de sons e imagens, inclusive em alta definição, da implantação dos equipamentos para transmissão, retransmissão e, principalmente, o impacto para o telespectador, que deverá se preparar para a recepção digital ou com substituição de seus televisores ou aquisição de set-top-box, em prazos já determinados pelo Ministério das Comunicações, sob o risco de não mais receber as transmissões de sinal da TV aberta brasileira a partir de 29 de junho de 2016. Este texto reflete sobre problemas no processo de implantação da transmissão digital brasileira que poderão comprometer a cobertura do território nacional com o sinal digital, limitar a capacidade de recepção em alta definição nas localidades mais afastadas dos grandes centros e, em consequência, implicar no atraso em se produzir conteúdo com os recursos disponibilizados pela nova tecnologia.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Televisão Digital: Informação e Conhecimento - FAAC