The aim of this thesis is to reconstruct 3D representation of underwater scenes from uncalibrated video sequences. Underwater visualization is important for underwater Remotely Operated Vehicles and underwater is a complex structured environment because of inhomogeneous light absorption and light scattering by the environment. These factors make 3D reconstruction in underwater more challenging. The reconstruction consists of the following stages: Image enhancement, feature detection and matching, fundamental matrix estimation, auto-calibration, recovery of extrinsic parameters, rectification, stereo matching and triangulation. For image enhancement, a pre-processing filter is used to remove the effects of water and to enhance the images. Two feature extraction methods are examined: 1. Difference of Gaussian with SIFT feature descriptor, 2. Harris Corner Detector with grey level around the feature point. Matching is performed by finding similarities of SIFT features and by finding correlated grey levels respectively for each feature extraction method. The results show that SIFT performs better than Harris with grey level information. RANSAC method with normalized 8-point algorithm is used to estimate fundamental matrix and to reject outliers. Because of the difficulties of calibrating the cameras in underwater, auto-calibration process is examined. Rectification is also performed since it provides epipolar lines coincide with image scan lines which is helpful to stereo matching algorithms. The Graph-Cut stereo matching algorithm is used to compute corresponding pixel of each pixel in the stereo image pair. For the last stage triangulation is used to compute 3D points from the corresponding pixel pairs.

This thesis is composed of three main parts / displaying an analog composite video input by via converting to digital VGA format, license plate localization on a video image and image enhancement on FPGA. Analog composite video input, either PAL or NTSC is decoded on a video decoder board / then on FPGA, video data is converted from 4:2:2 YCbCr format to RGB. To display RGB data on the screen, line doubling de-interlacing algorithm is used since it is efficient considering computational complexity and timing. When taking timing efficiency into account, image enhancement is applied only to beneficial part of the image. In this thesis work, beneficial part of the image is considered as numbered plates. Before image enhancement process, the location of the plate on the image must be found. In order to find the location of plate, a successful method, edge finding is used. It is based on the idea that the plate is found on the rows, where the brightness variation is largest. Because of its fast execution, band-pass filtering with finite response (FIR) is used for highlighting the high contrast areas. Image enhancement with rank order filter method is chosen to remove the noise on the image. Median filter, a rank order filter, is designed and simulated. To improve image quality while reducing the process time, the filter is applied only to the part of the image where the plate is. Design and simulation is done using hardware design language VHDL. Implementations of the chosen approaches are done on MATLAB and Xilinx Virtex-2 Pro FPGA. Improvement of the implementation considering speed and area is evaluated.

The aim of the study was to assess the feasibility of CT based 3D analysis of degenerated aortic bioprostheses to make easier their morphological assessment. This could be helpful during regular follow-up and for case selection, improved planning and mapping of valve-in-valve procedure. The challenge was represented by leaflets enhancement because of highly noised CT images. Contrast-enhanced ECG-gated CT scan was performed in patients with degenerated aortic bioprostheses before reoperation (in-vivo images). Different methods for noise reduction were tested and proposed. 3D reconstruction of bioprostheses components was achieved using stick based region segmentation methods. After reoperation, segmentation methods were applied to CT images of the explanted prostheses (exvivo images). Noise reduction obtained by improved stick filter showed best results in terms of signal to noise ratio comparing to anisotropic diffusion filters. All segmentation methods applied to the best phase of in-vivo images allowed 3D bioprosthetic leaflets reconstruction. Explanted bioprostheses CT images were also processed and used as reference. Qualitative analysis revealed a good concordance between the in-vivo images and the bioprostheses alterations. Results from different methods were compared by means of volumetric criteria and discussed. A first approach for spatiotemporal visualization of 3D+T images of valve bioprosthesis has been proposed. Volume rendering and motion compensation techniques were applied to visualize different phases of CT data. Native valve was also considered. ECG-gated CT images of aortic bioprostheses need a preprocessing to reduce noise and artifacts in order to enhance prosthetic leaflets. Stick based methods seems to provide an interesting approach for the morphological characterization of degenerated bioprostheses.

Background: Video surveillance is a growing area where it can help with deterring crime, support investigation or to help gather statistics. These are just some areas where video surveillance can aid society. However, there is an improvement that could increase the efficiency of video surveillance by introducing tracking. More specifically, tracking between cameras in a network. Automating this process could reduce the need for humans to monitor and review since the tracking can track and inform the relevant people on its own. This has a wide array of usability areas, such as forensic investigation, crime alerting, or tracking down people who have disappeared. Objectives: What we want to investigate is the common setup of real-time multi-target multi-camera tracking (MTMCT) systems. Next up, we want to investigate how the components in an MTMCT system affect each other and the complete system. Lastly, we want to see how image enhancement can affect the MTMCT. Methods: To achieve our objectives, we have conducted a systematic literature review to gather information. Using the information, we implemented an MTMCT system where we evaluated the components to see how they interact in the complete system. Lastly, we implemented two image enhancement techniques to see how they affect the MTMCT. Results: As we have discovered, most often, MTMCT is constructed using a detection for discovering object, tracking to keep track of the objects in a single camera and a re-identification method to ensure that objects across cameras have the same ID. The different components have quite a considerable effect on each other where they can sabotage and improve each other. An example could be that the quality of the bounding boxes affect the data which re-identification can extract. We discovered that the image enhancement we used did not introduce any significant improvement. Conclusions: The most common structure for MTMCT are detection, tracking and re-identification. From our finding, we can see that all the component affect each other, but re-identification is the one that is mostly affected by the other components and the image enhancement. The two tested image enhancement techniques could not introduce enough improvement, but other image enhancement could be used to make the MTMCT perform better. The MTMCT system we constructed did not manage to reach real-time.

Diss. (sammanfattning) Uppsala : Univ., 2007. / Härtill 4 uppsatser.

Thesis (M.S.D.)--Indiana University School of Dentistry, 2009. / Title from PDF t. p. (viewed Aug. 21, 2009) Advisor(s): Mychel Vail, Acting Chair of the Research Committee, Joseph Legan, Kenneth Spolnik, Susan L. Zunt, Edwin Parks. Curriculum vitae. Includes abstract. Includes bibliographical references (leaves 109-120).

O objetivo desta tese foi avaliar a interferência da presença de materiais metálicos na imagem radiográfica e tomográfica por meio da análise da adaptação marginal de restaurações e coroas metálicas. Esta investigação resultou em 3 artigos: uma revisão sistemática da literatura para identificar o estado da arte com relação ao uso dos métodos radiográficos; um estudo in vitro comparando o desempenho do filme radiográfico convencional e dos sistemas digitais VistaScan Dürr Dental, Digora Classic Soredex e Express Instrumentarium – com e sem o emprego de filtros para o pós processamento da imagem; e um estudo in vitro avaliando o processamento das imagens da TCFC – utilizando diferentes espessuras de reconstrução. Na revisão sistemática foram incluídos 14 estudos, sendo classificados de baixa ou moderada qualidade, de acordo com os critérios QUADAS de classificação. Na investigação radiográfica (artigo 2), os maiores valores de sensibilidade (0,67 0,83), especificidade (0,81 0,92) e acurácia (0,73 0,86) foram obtidos com radiografias convencionais e imagens digitais originais. Na avaliação tomográfica (artigo 3), os valores da aucROC variaram de 0,60 a 0,72, sendo que o limite inferior do intervalo de confiança mostrou-se abaixo ou muito próximo da linha de referencia. Frente aos resultados, conclui-se que imagens radiográficas originais (convencionais ou digitais) devem ser preferidas para a avaliação de dentes com restaurações metálicas. Quanto à TCFC, mesmo quando se aumenta a espessura de reconstrução da imagem e diminui-se o artefato, ainda assim não há melhora na acurácia do diagnóstico. / The aim of this thesis was to evaluate the interference of the presence of metallic materials on radiographic and tomographic image by assessing misfits tooth and restoration in metal-restored teeth. This investigation resulted in three articles: a systematic review of the literature to identify the state of the art on the use of radiographic methods; an in vitro study comparing the performance of conventional film and digital phosphor plate systems Vistascan Dürr Dental, Digora Classic Soredex and Instrumentarium Express – exported as original images and with the use of post processing filters; and an in vitro study evaluating the post-processing of CBCT images – using diverse reconstruction thicknesses. The systematic review retrived 14 studies, classified as low- / moderate quality based on QUADAS criteria. For radiographic evaluation (article II), higher sensitivity (0.67 0.83), specificity (0.81 0.92) and accuracy (0.73 0.86) values were obtained with conventional and digital original images. For tomographic evaluation (article III), mean aucROC ranged from 0.60 to 0.72, and the analysis of the 95% CI showed the lower bound of the curve bellow or very close to the reference line. Based on the results, it is concluded that original images (conventional or digital) should be preferred for the assessment of teeth with metal restorations. Considering CBCT images, even thought increased reconstruction thickness decreased perceived artifact, it did not improve diagnosis accuracy.

Made available in DSpace on 2014-06-11T19:25:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-09Bitstream added on 2014-06-13T19:52:59Z : No. of bitstreams: 1 monti_lm_me_araca.pdf: 287560 bytes, checksum: 074e03765d9ead5baba4ea3ffcdf36ee (MD5) / Universidade Estadual Paulista (UNESP) / Avaliou-se, por meio de exames radiográficos digitais e densitométricos, a influência do tipo de instrumento rotatório para corte, no processo de reparação óssea após osteotomias em mandíbula de suíno em tempos controlados. Foram utilizados para o estudo oito suínos da raça Large White, com peso corpóreo inicial variando de 25 a 30 Kg. Dois cortes transversais do meio à base de mandíbula direita foram realizados, um por meio de instrumento rotatório de alta rotação e o outro pela ação da baixa rotação, ambos com irrigação líquida. Após períodos pré-estabelecidos (7, 28, 60 e 90 dias) os animais foram sacrificados e suas mandíbulas retiradas para estudos radiográficos digitais diretos e indiretos, pelo sistema DIGORA e ODR e de densitometria óptica por imagens radiográficas pelo sistema CROMOX. Nos períodos iniciais (7 e 28 dias) as densitometrias foram maiores na região das osteotomias realizadas com alta rotação e nos períodos finais (60 e 90 dias) as densitometrias foram maiores nas osteotomias feitas com baixa rotação, indicando uma melhor reparação óssea final quando do uso de baixa rotação. A análise qualitativa do processo de reparação foi feita pelo sistema ODR, que possibilitou a obtenção de imagens digitais tridimensionais e coloridas, permitindo comparação das espessuras ósseas com as de uma cunha de alumínio, evidenciando que aos sessenta dias a reparação óssea estava aparentemente completa. Os histogramas do DIGORA apontaram valores de médias de nível de cinza nas áreas de osteotomia, evidenciando uma maior quantidade de tons de cinza nas osteotomias de alta rotação nos primeiros tempos, e nas osteotomias com baixa-rotação nos tempos finais. / It was evaluated, through digital and densitometric radiographic exams, the influence of the type of rotating instrument for cut, in the process of bony repair after osteotomy in swine jaw in controlled times. They were used for the study eight Large White swines, with initial corporal weight varying from 25 to 30 Kg. Two traverse cuts of the middle to the base of right jaw were accomplished, one through rotating instrument of high rotation and the other for the action of the low rotation, both with liquid irrigation. After established periods (7, 28, 60 and 90 days) the animals were sacrificed and your mandibles retired for direct and indirect digital radiografic studies, for the DIGORA and ODR systems and of optical densitometry for radiographic images for the CROMOX system. In the initial periods (7 and 28 days) the densitometry were larger in osteotomy areas accomplished with high rotation and in the final periods (60 and 90 days) the densitometry were larger in the osteotomy done with low rotation, indicating a better final bony repair when of the use of low rotation. The qualitative analysis of the repair process was made by the ODR system, that made possible obtaining three-dimensional and colored digital images, allowing comparison of the bony thickness with the one of a wedge of aluminum, evidencing that to the sixty days the bony repair was apparently complete. The histograms of DIGORA pointed values of the averages of ash tones in the osteotomy areas, evidencing a larger amount of ash tones in the osteotomy of high rotation in the first times, and in the osteotomy with low-rotation in the final times.

O objetivo desta tese foi avaliar a interferência da presença de materiais metálicos na imagem radiográfica e tomográfica por meio da análise da adaptação marginal de restaurações e coroas metálicas. Esta investigação resultou em 3 artigos: uma revisão sistemática da literatura para identificar o estado da arte com relação ao uso dos métodos radiográficos; um estudo in vitro comparando o desempenho do filme radiográfico convencional e dos sistemas digitais VistaScan Dürr Dental, Digora Classic Soredex e Express Instrumentarium – com e sem o emprego de filtros para o pós processamento da imagem; e um estudo in vitro avaliando o processamento das imagens da TCFC – utilizando diferentes espessuras de reconstrução. Na revisão sistemática foram incluídos 14 estudos, sendo classificados de baixa ou moderada qualidade, de acordo com os critérios QUADAS de classificação. Na investigação radiográfica (artigo 2), os maiores valores de sensibilidade (0,67 0,83), especificidade (0,81 0,92) e acurácia (0,73 0,86) foram obtidos com radiografias convencionais e imagens digitais originais. Na avaliação tomográfica (artigo 3), os valores da aucROC variaram de 0,60 a 0,72, sendo que o limite inferior do intervalo de confiança mostrou-se abaixo ou muito próximo da linha de referencia. Frente aos resultados, conclui-se que imagens radiográficas originais (convencionais ou digitais) devem ser preferidas para a avaliação de dentes com restaurações metálicas. Quanto à TCFC, mesmo quando se aumenta a espessura de reconstrução da imagem e diminui-se o artefato, ainda assim não há melhora na acurácia do diagnóstico. / The aim of this thesis was to evaluate the interference of the presence of metallic materials on radiographic and tomographic image by assessing misfits tooth and restoration in metal-restored teeth. This investigation resulted in three articles: a systematic review of the literature to identify the state of the art on the use of radiographic methods; an in vitro study comparing the performance of conventional film and digital phosphor plate systems Vistascan Dürr Dental, Digora Classic Soredex and Instrumentarium Express – exported as original images and with the use of post processing filters; and an in vitro study evaluating the post-processing of CBCT images – using diverse reconstruction thicknesses. The systematic review retrived 14 studies, classified as low- / moderate quality based on QUADAS criteria. For radiographic evaluation (article II), higher sensitivity (0.67 0.83), specificity (0.81 0.92) and accuracy (0.73 0.86) values were obtained with conventional and digital original images. For tomographic evaluation (article III), mean aucROC ranged from 0.60 to 0.72, and the analysis of the 95% CI showed the lower bound of the curve bellow or very close to the reference line. Based on the results, it is concluded that original images (conventional or digital) should be preferred for the assessment of teeth with metal restorations. Considering CBCT images, even thought increased reconstruction thickness decreased perceived artifact, it did not improve diagnosis accuracy.

Orientador: Francisco Haiter Neto / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-10T07:50:35Z (GMT). No. of bitstreams: 1 Bittar-Cortez_JulianaAraujo_D.pdf: 5858192 bytes, checksum: 3d3d3c7dbc08b34e4b7c483e7316bd88 (MD5) Previous issue date: 2008 / Resumo: O objetivo deste estudo in vitro foi comparar dois protocolos de remineralização em lesões de cárie no esmalte dentário, avaliados por meio de análises de cálcio (Ca) e fósforo (Pi), dureza do esmalte, microscopia de luz polarizada e subtração radiográfica digital (SRD); avaliar a viabilidade da utilização de dois diferentes sistemas de radiografias digitais, placa PSP (photostimulable storage phosphor) e sensor CMOS (complementary metal oxide semicondutor), no diagnóstico de desmineralizações, e a acurácia das radiografias digitais convencionais (RDC) e três métodos de SRD (linear, avançada e logarítmica) no diagnóstico de mudanças minerais; e comparar o ruído e reprodutibilidade das imagens de SRD lineares e logarítmicas produzidas a partir de dois sistemas de radiografias digitais. Para isso, lesões de cárie artificiais foram criadas em 100 superfícies proximais de dentes hígidos. Vinte dentes foram mantidos como controle e oitenta foram submetidos a dois diferentes protocolos de remineralização em 4 e 8 semanas, com a contínua imersão em saliva artificial e um tratamento adicional com flúor. Radiografias digitais foram realizadas antes e depois dos protocolos de remineralização. Cinco examinadores avaliaram a desmineralização e as mudanças minerais nas RDC, dispostas lado a lado, e três métodos da SRD. As análises de Ca / Pi e a colocação dos dentes na solução remineralizante foram considerados como padrão ouro. A média dos tons de cinza e o desvio padrão (DP) no histograma foram também mensurados. As concentrações de Ca e Pi na saliva artificial após os tratamentos foram significativamente menores do que a solução original (p<0,05); e por meio da SRD foi possível verificar diferenças entre as imagens. Entretanto, o teste de dureza e a microscopia de luz polarizada não detectaram nenhuma alteração. O sistema CMOS foi significativamente mais acurado do que a sistema PSP no diagnóstico da desmineralização e mudanças minerais, assim como a SRD linear no diagnóstico de mudanças minerais. Também foram estatisticamente diferentes os valores da média dos níveis de cinza e do DP entre os dois sistemas. Foi concluído que (a) o tratamento adicional de flúor promoveu valores maiores de ganho mineral; (b) a análise de Ca / Pi na saliva artificial foi o método mais sensível na avaliação de alteração mineral; (c) a imagem de SRD linear é um método válido na detecção do aumento de intensidade, como sinal de ganho mineral; e (d) as imagens de SRD utilizando as placas PSP tiveram um menor ruído do que nas imagens geradas pelo sensor CMOS / Abstract: The aim of this in vitro study was to compare two remineralization protocols of artificial carious lesions in enamel, evaluated by Calcium (Ca) and Phosphorus (Pi) analysis, cross-section hardness test, polarized light microscopy and digital subtraction images (DSR); to assess the feasibility of using two different systems of digital radiography, photostimulable storage phosphor (PSP) plate and complementary metal oxide semiconductor (CMOS) sensor on the demineralization diagnosis, and the accuracy of digital conventional radiographs (DCR) and three methods of DSI (linear, advanced and logarithmic) on mineral changes diagnosis; and, to compare noise and reproducibility in linear and logarithmic DSI produced from two digital radiography systems. Artificial caries-like lesions on 100 approximal surfaces of sound teeth were produced. Twenty teeth were kept as control and eighty teeth were subjected to two different remineralization protocols for 4 and 8 weeks, with continuous immersion in artificial saliva, and additional fluoride treatment. Digital radiographs were taken before and after the remineralization protocols. Five examiners assessed demineralization and mineral changes on DCR, placed side by side, and three methods of DSI. Ca / Pi analysis and the placement of the teeth on the remineralization solution was the gold standard. The mean shades of gray and the standard deviation (SD) of the histogram were also assessed. The concentrations of Ca and Pi in the artificial saliva after the treatments were significantly lower than the original solution (p<0.05); and DSR showed differences between the images. However, the Hardness test and polarized light microscopy did not detect any changes. CMOS system was significantly more accurate than PSP system on demineralization and mineral changes diagnosis, and also linear DSR on mineral changes diagnosis. It was also statistically significant different the values of mean shades of gray and SD between both systems. It was concluded that (a) the additional Fluoride treatment provided higher values of mineral gained; (b) Ca / Pi analysis in the artificial saliva were the most sensitive method of mineral change evaluation; (c) linear DSI is a valuable method to disclose an intensity increase, as a sign of mineral gained; and (d) DSR images created from PSP plates had less noise than images produced from CMOS sensor / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica