Radiografia digital para inspeção de soldas de dutos - melhor sensibilidade

The conventional radiographic technique using industrial radiographic films is with the days finishing. The Digital Radiography is taking place in several sectors, e.g., the medical, aerospace, security, automotive, etc. In addition to representing a technological trend, it has been demonstrated that digital radiography offers a series of benefits in terms of productivity, sensitivity, environmental aspects, image treatment tools, cost reduction, etc. If one weld seam to be inspected is from a serried product, as example a pipe, the best option to be implemented is the Flat Panel Detector with this equipment is possible to reduce the obtaining digital radiographic images in place of films and reducing the inspection cycle time due to its high degree of automation. In the experiments described in this paper this new technique was tested and the results were compared with those obtained by the conventional radiography. The welded specimens were prepared using the submerged-arc welding process and small artificial cracks of the most varied dimensions, present in the specimens, were used to establish a comparison of the sensitivities presented by the techniques employed After conducting several experiments, the digital method presented the highest sensitivity to the wire-type Image Quality Indicator (IQI) and in the detection of small defects, leading to the conclusion that the use of digital radiography using the flat-panel detector offers advantages over the conventional technique [1, 2]. This work was carried out based on the API 5L Edition 2004 [3] and ISO 3183 Edition 2007 [4] specifications.

Construção de mosaicos georreferenciados usando imagens aéreas de pequeno formato

In this work we propose a technique that uses uncontrolled small format aerial images, or SFAI, and stereohotogrammetry techniques to construct georeferenced mosaics. Images are obtained using a simple digital camera coupled with a radio controlled (RC) helicopter. Techniques for removing common distortions are applied and the relative orientation of the models are recovered using projective geometry. Ground truth points are used to get absolute orientation, plus a definition of scale and a coordinate system which relates image measures to the ground. The mosaic is read into a GIS system, providing useful information to different types of users, such as researchers, governmental agencies, employees, fishermen and tourism enterprises. Results are reported, illustrating the applicability of the system. The main contribution is the generation of georeferenced mosaics using SFAIs, which have not yet broadly explored in cartography projects. The proposed architecture presents a viable and much less expensive solution, when compared to systems using controlled pictures

Extração semiautomática de rodovias no espaço-objeto: uso integrado de um estereopar de imagens aéreas e um MDT

Neste artigo é proposto um método semiautomático para extração de rodovias combinando um estereopar de imagens aéreas de baixa resolução com um poliedro gerado a partir de um modelo digital do terreno (MDT). O problema é formulado no espaço-objeto através de uma função objetivo que modela o objeto 'rodovia' como uma curva suave e pertencente a uma superfície poliédrica. A função objetivo proposta depende também de informações radiométricas, que são acessadas no espaço-imagem via relação de colinearidade entre pontos da rodovia no espaço-objeto e os correspondentes nos espaços imagem do estereopar. A linha poligonal que melhor modela a rodovia selecionada é obtida por otimização no espaço-objeto da função objetivo, tendo por base o algoritmo de programação dinâmica. O processo de otimização é iterativo e dependente do fornecimento por um operador de uma aproximação inicial para a rodovia selecionada. Os resultados obtidos mostraram que o método é robusto frente a anomalias existentes ao longo das rodovias, tais como obstruções causadas por sombras e árvores.

Evaluation of digital optical density of bone repair in rats medicated with ketoprofen

O objetivo deste estudo foi avaliar a influência do cetoprofeno sobre o processo de reparação óssea em tíbias de ratos, por meio da análise da densidade óptica digital. Vinte ratos da linhagem Wistar foram divididos em 2 grupos: um grupo controle (sem tratamento) e um grupo tratado com cetoprofeno. Os procedimentos experimentais consistiram de: anestesia, cirurgia, administração do cetoprofeno e exame radiográfico. As imagens radiográficas foram adquiridas empregando-se o sensor digital Visualix GX-S-HDI™ e um aparelho de raios X. As radiografias foram realizadas nos períodos baseline (inicial), 7, 14, 21 e 30 dias pós-operatório, sendo a densidade óptica (DO) avaliada por meio do sistema Vix winTM 1.4. Os valores médios da leitura da do obtidos foram analisados estatisticamente por meio de ANOVA e teste de Tukey com nível de significância de 5%. No grupo controle, houve diferença estatisticamente significante (p=0,001) entre o tempo e a DO, enquanto no grupo tratado com cetoprofeno a diferença não foi estatisticamente significante (p=0,100). O grupo controle apresentou as menores proporções de do (%) no 1º e 7º dias e as maiores proporções de do (%) no 14º, 21º e 30º dias, com diferença estatisticamente significante (p=0,001). Não houve diferença estatisticamente significante (p=0,100) entre as proporções médias de do (%) no grupo tratado, independentemente do período de avaliação. Os achados deste trabalho sugerem que houve influência do cetoprofeno sobre o processo de reparo ósseo, uma vez que na primeira semana o medicamento proporcionou aumento na densidade óptica e provocou atraso na neoformação óssea após o 21º dia.

Extração semi-automática de rodovias em um par de imagens aéreas digitais utilizando geometria epipolar e programação dinâmica

The purpose of this paper is to introduce a methodology for semi-automatic road extraction from aerial digital image pairs by using dynamic programming and epipolar geometry. The method uses both images from where each road feature pair is extracted. The operator identifies the corresponding road featuresand s/he selects sparse seed points along them. After all road pairs have been extracted, epipolar geometry is applied to determine the automatic point-to-point correspondence between each correspondent feature. Finally, each correspondent road pair is georeferenced by photogrammetric intersection. Experiments were made with rural aerial images. The results led to the conclusion that the methodology is robust and efficient, even in the presence of shadows of trees and buildings or other irregularities.

Automated extraction of road network from medium-and high-resolution images

This paper presents an automatic methodology for road network extraction from medium-and high-resolution aerial images. It is based on two steps. In the first step, the road seeds (i.e., road segments) are extracted using a set of four road objects and another set of connection rules among road objects. Each road object is a local representation of an approximately straight road fragment and its construction is based on a combination of polygons describing all relevant image edges, according to some rules embodying road knowledge. Each road seed is composed by a sequence of connected road objects in which each sequence of this type can be geometrically structured as a chain of contiguous quadrilaterals. In the second step, two strategies for road completion are applied in order to generate the complete road network. The first strategy is based on two basic perceptual grouping rules, i.e., proximity and collinearity rules, which allow the sequential reconstruction of gaps between every pair of disconnected road segments. This strategy does not allow the reconstruction of road crossings, but it allows the extraction of road centerlines from the contiguous quadrilaterals representing connected road segments. The second strategy for road completion aims at reconstructing road crossings. Firstly, the road centerlines are used to find reference points for road crossings, which are their approximate positions. Then these points are used to extract polygons representing the contours of road crossings. This paper presents the proposed methodology and experimental results. © Pleiades Publishing, Inc. 2006.

Um estudo sobre o osu do modelo de cor RGB no proceso de correspondência por correlação

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

Protecting medical images with biometric information

Medical images are private to doctor and patient. Digital medical images should be protected against unauthorized viewers. One way to protect digital medical images is using cryptography to encrypt the images. This paper proposes a method for encrypting medical images with a traditional symmetric cryptosystem. We use biometrics to protect the cryptographic key. Both encrypted image and cryptographic key can be transmitted over public networks with security and only the person that owns the biometrics information used in key protection can decrypt the medical image. © Springer Science+Business Media B.V. 2008.

Técnicas de correlação no delineamento de feições rodoviárias em imagens de baixa e média resolução

This paper presents a method for the sequential road feature delineation from digital images. It is based on a feedback loop between extrapolation and refinement steps of a given road centerline point, using in both steps correlation techniques. Firstly, a previously extracted road centerline point is linearly extrapolated, resulting in an approximate position. Secondly, this approximate position is corrected by comparing gray level profiles extracted perpendicularly to the extrapolation direction. This strategy is then repeated to allow the entire road centerline to be extracted or a stop point to be found. In order to initialize the extraction process, the operator needs to supply a starting point plus direction and width. Experimental results obtained from the application of the method to real image data are presented and discussed in this paper.

Extração semi-automática de rodovias no espaço-objeto: uso integrado de um estéreo par de imagens aéreas e um MDT

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Formação de imagens multiespectrais por meio de fusão de imagens adquiridas por múltiplas câmaras

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Detecção de áreas de oclusão para geração de ortoimagem verdadeira utilizando dados LASER

Pós-graduação em Ciências Cartográficas - FCT

Imagem digital em movimento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Eliminação de ruído impulsivo em imagens coloridas usando um filtro mediano seletivo e retoque digital

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Subtração digital radiográfica: identificação precoce de perdas minerais em esmalte

Pós-graduação em Biopatologia Bucal - ICT