996 resultados para Processamento de imagens - Técnicas digitais


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The analysis of natural processes, such as landslides, has a great importance for the prevention of accidents in pipelines, since it might compromise its security, with serious social and environmental implications. Considering the large territorial dimensions that pipelines can reach, remote sensing tools have great applicability for data acquisition, allowing the analysis of large areas in regular time periods. This study aims to analyze the relations between the occurrence of landslides and its natural conditionings, on a stretch of the ORBEL pipeline, in the municipalities of Duque de Caxias, Nova Iguaçu and Belford Roxo – Rio de Janeiro. GeoEye sensor system images were used with spatial resolution of 0.5 m, from November/2009, January/2010 and March/2010, that are months of summer rains. The work involved the characterization of the study area and existing landslides, through bibliographic data collection; the application of visual analysis techniques for the extraction of landslide scars and fractures; preparation of maps for the landslide constraints and preparation of the susceptibility map. In the images from November only three landslide scars were extracted, while in January there were 166 and 111 in March. Difficulties were found with the shading in the images. From the relations among landslide scars, lithological units, relief systems, slope, downhill profile and the generated map of landslide susceptibility, presented in 1:70,000 scale, it was possible to conclude that slope is the main determinant of the process, allied secondarily to downhill profile, relief systems and lithology

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The aim of this work is to study some of the density estimation tec- niques and to apply to the segmentation of medical images. Medical images are used to help the diagnostic of tumor diseases as well as to plan and deliver treatment. A computer image is an array of values representing colors in some scale. The smallest element of the image to which it is possible to assign a value is called pixel. Segmen- tation is the process of dividing the image in portions through the classi¯cation of each pixel. The simplest way of classi¯cation is by thresholding, given the number of portions and the threshold values. Another method is constructing a histogram of the pixel values and assign a portion to each pike. The threshold is the mean between two pikes. As the histogram does not form a smooth curve it is di±cult to discern between true pikes and random variation. Density estimation methods allow the estimation of a smooth curve. Image data can be considered as mixture of different densities. In this project parametric and nonparametric methods for density estimation will be addressed and some of them are applied to CT image data

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Nuclear medicine is a medical specialty related to imagery that deals with imaging techniques, diagnosis and therapy, allowing observing the physiological state of tissues noninvasively by marking the molecules participating of these physiological processes with radioactive isotopes, thus creating the called radionuclides. The image of a radionuclide is one of the most important applications of radioactivity in nuclear medicine. The equipment’s of nuclear medicine imaging use the principle of radiation detection, turning it into an electrical signal which, through specific algorithms, allows forming tomographic images that provide information about the functional status of organs. New detection systems have been developed for tomographic acquisitions using solid state detectors. These devices use crystals of cadmium zinc telluride (CdZnTe). Some of the advantages of this detector are a significant improvement of signal to noise ratio, the increased spectral and spatial resolution, which in sum, result in greater clarity of the images obtained, opening new perspectives for imaging protocols previously unattainable. In contrast, all other gamma-cameras equipped with vacuum tubes have remained relatively unchanged for nearly fifty years. In these gamma-cameras, the images are obtained using two steps significantly less efficient: the gamma rays are converted to light through a first device, and then the light is converted into an electrical signal through a second device. One of functions the Medical Physicist is related to the quality control of equipment. This control ensures that the information and images provided are true and thus credible to be used in medical reports. To perform this type of analysis the physicist must understand the performance characteristics and operation of all equipment of the department concerned; besides, in the absence of specific legislation, proposing...(Complete abstract click electronic access below)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In order to assure the maintenance of foods integrity and quality, for avoiding chemical, physical or biological contamination, it is essential to follow the Good Manufacturing Practices (GMP). Among the techniques used for evaluating GMP there is the observational analysis carried out by means of a check-list form application. The present study evaluated the suitability of GMP in a dairy industry producer of Minas fresh and ricotta cheeses, located in São José do Rio Preto, SP, by applying a check-list form. A significant improvement in conformity was evidenced, increasing from 43% to 78%. Neither the blocks related to the handlers nor the existing documentation in the company showed any improvements, as poor conditions unchanged. All of the other evaluated blocks showed significant improvement after applying the GMPrelated corrective measures. Based on these findings, the observance of corrective measures by the dairy industry on dairy products, physical environment, GMP, and handlers training was crucial for assuring the improvements and to increase the product quality and consumers safety.

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This paper considers a study of the anatomical features of the cardiac system and a three-dimensional model of the different tunics that comprise the heart wall, for processing and quality control of radiological images. The structures are built by the layer overlapping method, where a layer can be understood as a slice of the three-dimensional object. The pericardium, myocardium and endocardium were represented with three-dimensional cylinders and hexagons. The spatial arrangement of the cardiac system is determined by an background image of a real model, which values are defined according to the shape of the region and on the anatomical patients characteristics. The results are significant, considering the anatomical structures details, as well as the representation of the thicknesses of the regions of the heart wall. The validation of the anatomical model was accomplished through comparisons with dimensions obtained from a real model and allows verifying that the model is appropriate. The degree of representation will allow the verification of the influence of radiological parameters, morphometric peculiarities and stage of the diseases on the quality of the images, as well as on the performance of the Computer-Aided Diagnosis (CAD).

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Recognition of individuals through the characteristics of the iris has in recent years become a well accepted technique due to both the high reliability of this procedure and the its non invasiveness. The methods used in such procedures seek information all over the iris, which depending on the algorithm used may result in high computational costs. Considering that most characteristics of the iris are in its inner region the goal of this work is to develop an algorithm for the recognition of individuals using only this region. To bring the outcome of our approach to the level of the best techniques described in the literature this technique has to be further elaborated, even so the results show a promising technique.

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Pós-graduação em Agronomia - FEIS

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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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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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As mordidas cruzadas anteriores e posteriores podem ser tratadas desde as dentaduras decídua e mista. Embora a literatura descreva diversas técnicas para a correção individualizada desses problemas, o tratamento de pacientes com as duas alterações é pouco documentado. O presente artigo relata o tratamento desses problemas com o expansor tipo Haas associado a molas digitais. Essa alternativa apresenta boa previsibilidade, fácil confecção e instalação, e ótima eficiência.