Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho são apresentados os resultados obtidos com a quantificação de parâmetros - por meio de técnicas de histomorfometria - de amostras de espumas cerâmicas. Esta quantificação foi feita por meio de análise de imagens bidimensionais a partir de técnicas de processamento de imagens digitais. As imagens analisadas neste trabalho foram obtidas através de digitalização das faces das amostras com o uso de um scanner convencional e os dados obtidos para cada amostra de espuma foram comparados com os resultados encontrados com a utilização de imagens tomográficas e um aplicativo desenvolvido para a análise de tais imagens. Os ensaios realizados com as amostras citadas mostram que a utilização do scanner convencional para a aquisição das imagens é vantajosa sob o ponto de vista da facilidade de obtenção de tais imagens e que a quantificação histomorfométrica pode ser feita a partir de imagens 2D desses objetos. / In this work will present the results obtained with quantification of parameters by means of histomorphometry techniques of ceramic foam samples. This quantification was done by means of two-dimensional image analysis techniques from image processing. The images analyzed in this work were obtained by scanning the faces of the samples using a conventional scanner and the data obtained for each sample were compared with results obtained by use of tomographic images and an application developed for the analysis of such images. Tests conducted whit the samples mentioned show the use of conventional scanner for image acquisition is advantageous from the point of view of obtaining such images and the histomorphometric quantification can be made in 2D images of the faces of these objects.

Orientador: Regina Helena Pereira Johas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-16T14:23:39Z (GMT). No. of bitstreams: 1 Guideroli_IlmaCarlaZarotti_M.pdf: 37001017 bytes, checksum: c43b5a3b57dfe1e23b24169201dd8910 (MD5) Previous issue date: 2010 / Resumo: A pesquisa Entre Mapas, Entre Espaços: Itinerários Abertos consiste no mapeamento de minha produção plástica no período entre o início de 2008 e o início de 2010. É formada por quatro livros de artista intitulados Lugares Imaginários I, II, III e IV e Espaços Afluentes, composto por dezoito imagens digitais divididas entre as séries Rotas Imaginárias, São Paulo, Intersecções I, Paisagens Mapeadas, UnHorizont e Paisagem Oceânica. Ambos partilham o mesmo campo de investigações, composto de três eixos norteadores que sustentam pensamento e processo criativo. O primeiro destes eixos trata de TranSituAções, conceito que abrange as diferentes maneiras de conceber espaço e lugar, apresentado a partir da reflexão de autores que discutiram este tema. O segundo eixo estrutura a proposição Espaços Empilhados, tratados a partir da definição do virtual segundo Pierre Lévy e do conceito de remix cunhado por Lev Manovich e citado, por sua vez, por autores brasileiros que destrincharam o assunto, como André Lemos e Marcus Bastos. O terceiro e último eixo aborda a questão dos mapas, sendo que a primeira parte compreende uma breve história da cartografia com seu surgimento e características específicas; e a segunda parte consiste na investigação dos mapas deturpados, ou seja, como alguns escritores, artistas e cineastas fizeram uso dos mapas convencionais, tirando deles a função utilitária de localização em relação ao lugar físico. O corpo prático reflexivo aqui apresentado pretende situar meus trabalhos dentro de questionamentos pertinentes ao nosso tempo, e inserir tal pesquisa como resultado de uma investigação que não se encerra, mas continua infinitamente / Abstract: The research Among Maps, Among Spaces: Open Itineraries consists in mapping my artistic practice from the beginning of 2008 until the beginning of 2010. It is composed of four artist's books entitled Imaginary Places I, II, III, and IV, and Affluent Spaces, composed of eighteen digital images divided in the series Imaginary Routes, São Paulo, Intersections I, Mapped Landscapes, UnHorizont, and Oceanic Landscape. Both works share the same investigations, composed of three guiding axes that support thoughts and the creative process. The first axis approaches TranSituActions, a concept that comprises different ways of conceiving space and place, presented from the reflection of authors that investigate this theme. The second axis structures the proposition Heaped Spaces, treated from the definition of virtual according to Pierre Lévy and the concept of remix, coined by Lev Manovich and cited by Brazilian authors that explained the subject, like André Lemos e Marcus Bastos. The last axis approaches the question of maps: the first part comprehends a brief history of cartography with its appearance and specific characteristics and the second one consists of investigating the corrupted maps, that is, how some writers, artists and filmmakers used conventional maps, extracting from them the utilitarian function of localization in relation to a geographic place. The practical-reflexive body presented here intends to place my works inside relevant questions to our time, and introduce such research as a result of an investigation that does not close but continues infinitely / Mestrado / Artes / Mestre em Artes

Orientador: Paulo Roberto Gardel Kurka / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T00:20:23Z (GMT). No. of bitstreams: 1 Rudek_Marcelo_D.pdf: 2300973 bytes, checksum: e02ac88751e4619e52590e1ee9fb82b5 (MD5) Previous issue date: 2006 / Resumo: O trabalho apresenta um método baseado em imagens digitais para a determinação da posição espacial e do volume ocupado por um sólido. O objetivo é conhecer estes parâmetros sem a necessidade da reconstrução tridimensional completa do objeto. A aplicação da técnica proposta é baseada nas projeções da imagem do objeto a ser medido. O processo se baseia na utilização de uma caixa de contorno (bounding box) que pode ser ajustada sobre uma região de interesse na imagem. A posição desta caixa de contorno descreve a orientação espacial do objeto, e as suas dimensões espaciais definem o volume aproximado do sólido. O trabalho propõe um método para ajustar as arestas da caixa de contorno sobre as bordas do objeto, usando como referencial os pontos de fuga que formam os vértices da caixa de contorno. Os vértices formam um conjunto reduzido de pontos e a reconstrução tridimensional destes pontos permite definir um polígono retangular no espaço que representa as informações métricas do objeto real. O contexto do trabalho se situa no campo da visão computacional e processamento de imagens utilizando um conjunto de ferramentas aplicadas à teoria de reconstrução 3D. São apresentados os resultados obtidos da aplicação do método para imagens reais, bem como é descrita uma aplicação do método em um ambiente de manufatura integrada / Abstract: This work presents a method based on digital images to determine the spatial position and volume occupied by a solid. The objective is to find these parameters without a complete tri­dimensional reconstruction of the object. The application of this technique is based on the image projections of a solid target. The process is based on a contour bounding box that is adjusted around a region of interest. The box position describes the object spatial orientation and its spatial dimensions can define the approximated volume. The work proposes a method to adjust the contour box lines on the object borders using vanishing points as reference to form each vertex of the bounding box. The vertices form a reduced set of points and the 3D reconstruction of such points can define a rectangular polygon in the space representing the metric information about the real object. The work is within the context of computer vision and image processing by the use of a set of 3D reconstruction tools. Results obtained of the application of this method to real images are presented, as well as an application to an integrated manufacturing process / Doutorado / Projeto Mecanico / Doutor em Engenharia Mecânica

Orientadores: Antonio Celso Fonseca de Arruda, Roberto de Alencar Lotufo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-22T16:25:26Z (GMT). No. of bitstreams: 1 Maschio_Celio_M.pdf: 7517102 bytes, checksum: b541bb4f611106b935e681d6189f03a7 (MD5) Previous issue date: 1997 / Resumo: A tomografia computadorizada de raios-x tem extrapolado a área médica e ganhado campo em inúmeras aplicações onde se faz necessária a interpretação (qualitativa e quantitativa) da estrutura interna de um material opaco, sem destruí-lo. O presente trabalho demonstra a aplicação desta técnica em ensaios não destrutivos, utilizando-se amostras de materiais e componentes de diferentes densidades e geometrias, com defeitos simulados e reais, ensaiados em tomógrafos médicos. Demonstra-se, também, o uso da técnica na caracterização de filtros eletroquímicos usados para remoção de agentes contaminantes (no caso, zinco) de efluentes industriais. Foram usadas técnicas de processamento digital de imagens (sistema Khoros) para a caracterização dos defeitos encontrados, através da medida do coeficiente de atenuação do material em regiões de interesse, e por meio do cálculo de parâmetros dimensionais tais como área e perímetro. Foram aplicadas operações de filtragem matemática para a correção do efeito de endurecimento de feixe, verificado nas imagens de materiais metálicos, sobretudo no alumínio. Devido à sua natureza qualitativa e quantitativa, a tomografia computadorizada de raios-x demonstrou ser uma ferramenta promissora em ensaios não destrutivos de materiais. Este trabalho demonstra e reforça sua aplicabilidade através do uso de processamento digital de imagens / Abstract: X-ray computed tomography (XCT), originally developed for medical purposes is becoming increasingly applied to several applications where it is necessary the interpretation of the internal structure of an object nondestructively. The present work shows the application of this technique to nondestructive testing using materiaIs and components of different density and geometry, with simulated and real defects tested in a medical scanner. Characterization of electrochemical filters used to remove contamination agents (in this case, zinc) in industrial effluents, by XCT technique is also described. Digital image processing have been used (software Khoros) for defects characterization, determining the attenuation coefficient in regions of interest and measuring parameters like area and perimeter. Digital filtering operations have been applied for beam hardening correction in metallic materiaIs images, mainly aluminum. Due its qualitative and quantitative nature, XCT technique established to be a promising tool of nondestructive materiaIs evaluation and this work emphasizes its applicability through digital image processing / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Orientador: Antonio Celso Fonseca de Arruda / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-31T14:51:24Z (GMT). No. of bitstreams: 1 Maschio_Celio_D.pdf: 13410400 bytes, checksum: bcad1a44963fabb3c498533b4663302a (MD5) Previous issue date: 2001 / Resumo: O objetivo deste trabalho foi o desenvolvimento de metodologias para o estudo de filtros e processos de filtração, utilizando a tomografia de raios-X, técnicas de processamento digital de imagens e simulação numérica. Os ensaios convencionais utilizados pelos fabricantes são realizados através da medida de parâmetros, tais como pressão e vazão, em pontos localizados a montante e a jusante do filtro. Estes ensaios não são eficientes na caracterização de defeitos e não revelam como ocorre o processo de saturação no interior do filtro. Neste trabalho, a tomografia de raios-X foi utilizada para duas finalidades básicas: estudar a distribuição de contaminantes e analisar defeitos no interior de elementos filtrantes. Os modelos de filtração encontrados na literatura não levam em conta o efeito do acúmulo de contaminantes no desempenho do filtro ao longo do processo de filtração. Neste trabalho, foi desenvolvido um modelo acoplando-se as equações de filtração com as equações fenomenológicas (lei de Darcy e equação da continuidade), de tal forma que o acúmulo de partículas no meio poroso (filtro) fosse considerado na simulação do processo de filtração. Os resultados demonstraram que o processo de saturação no interior dos elementos analisados não ocorre de forma homogênea, ou seja, o acúmulo de partículas é predominante em determinadas regiões. Em geral, há formação de canais preferenciais e o espaço interno do filtro não é totalmente utilizado na captura de partículas. Demonstrou-se também que, em alguns casos, o comportamento do filtro não é coerente com a especificação do fabricante. Foi possível, por fim, a utilização dos dados experimentais, obtidos via tomografia, para a validação do modelo teórico desenvolvido / Abstract: The development of methods for analysis of filters and filtration process, using X-ray computerized tomography, digital image processing and numerical simulation, was the objective of this work. Tests conventionally used by filter manufacturers are made through the measurement ofparameters, such as flow and pressure, at upstream and downstream ofthe filter. These tests are not efficient in the characterization of defects and do not reveal how the saturation process occurs within the filter. In this work, X-ray computerized tomography was used for two basic purposes: to evaluate contaminant distribution and to detect defects within the interior of the filter elements. The filtration models found in the literature do not consider the effect of contaminant concentration on the filter efficiency during the filtration processo In this work, filtration equations and phenomenological equations (Darcy's law and continuity equation) were coupled and a model that takes into account the contaminant accumulation on the filter performance was developed. The results demonstrated that the saturation process within the analyzed filters is not homogeneous, that is, the accumulation of partic1es is predominant in some regions. Generally, there are preferential channels and the interior of the filter elements is not totally utilized. In some cases, it was also demonstrated that the filter behavior does not agree with the manufacturer specifications. Finally, it was possible to use the experimental data obtained with X-ray computerized tomography, in order to validate the theoretical developed model / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Orientadores: Yuzo Iano, Ana Lucia Mendes Cruz Silvestre da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-14T10:02:55Z (GMT). No. of bitstreams: 1 Oliveira_Lucasde_M.pdf: 5052260 bytes, checksum: 34b1fa9e0e25d00990c118c6c93f964c (MD5) Previous issue date: 2009 / Resumo: O campo de análise e compressão de imagens tem recebido especial atenção da comunidade científica recentemente por abranger os principais sistemas de TV digital, comunicações via satélite e comunicações móveis. Neste contexto, as Transformadas Wavelets Discretas (TWD) surgem como uma ferramenta poderosa e suas inúmeras vantagens permitiram sua inserção em importantes padrões tais como JPEG2000, MPEG4 e MPEG7. O método lifting realiza a TWD sub-amostrando o sinal antes do processo de filtragem, implicando em rápido processamento por fazer uso das similaridades entre filtros passa-alta e passa-baixa, acelerando o cálculo dos coeficientes. Na literatura, ganhos aritméticos teóricos de diferentes proporções foram obtidos sobre o método tradicional, destacando-se os trabalhos de Daubechies e Sweldens e de Reichel. O objetivo desta pesquisa consiste em estender esta discussão de resultados teóricos quando implementados através de ferramentas, interpretada e compilada, focando no tempo de processamento necessário para a realização (decomposição e reconstrução) de diferentes imagens estáticas empregando wavelets pertencentes às famílias de Daubechies, Symlets e Biortogonais. Medidas de PSNR foram utilizadas de forma a corroborar a perfeita implementação do lifting, dado que o mesmo não pode implicar em deterioração na imagem reconstruída. / Abstract: The field of analysis and compression of images has been received special attention of the scientific community because of including in the main systems of digital TV, satellite communications and mobile communications. In this context, the Discrete Transform Wavelet (TWD) arise how a powerful tool and its many advantages allowed your insertion in important standards such as JPEG2000, MPEG4 and MPEG7. The lifting method realizes the TWD sub-sampling the signal before the filtering, resulting in faster processing by using the similarities between high and low pass filters, speeding up the calculation of coefficients. In the literature, arithmetic theoretical gains of different proportions were obtained on the traditional method, especially the works of Daubechies and Sweldens and of Reichel. The objective of this research is to extend this discussion of theoretical results when implemented through tools, interpreted and compiled, targeting the processing time required to perform (decomposition and reconstruction) of different images using wavelets belonging to the families of Daubechies, and Symlets Biortogonais. Measures of PSNR were used to corroborate the perfect implementation of the lifting, since that cannot result in deterioration in the reconstructed image. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

Orientadores: Carlos Roberto de Souza Filho, Emilson Pereira Leite / Acompanhado de 1 mapa (folha solta dobrada) / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-20T13:02:06Z (GMT). No. of bitstreams: 1 Barbuena_Danilo_M.pdf: 27016795 bytes, checksum: 3180173cfc829018bd7f9a63e218afce (MD5) Previous issue date: 2012 / Resumo: A Provincia Aurifera de Alta Floresta (PAAF) situa-se na porcao centro-sul do craton Amazonico, entre os limites das Provincias Ventuari - Tapajos (1,95-1,8 Ga) e Rio Negro - Juruena (1,8-1,55 Ga). Em seu segmento leste, ocorrem mais de uma centena de depositos auriferos hospedados em rochas plutonicas e vulcanicas e concentrados ao longo do Cinturao Peru-Trairao, de direcao NW-SE. Inseridos neste cenario geologico, proximos ao municipio de Peixoto de Azevedo e a Vila Uniao do Norte, estao os depositos Pe Quente e Francisco, alvos deste trabalho. Em funcao de varios fatores como a dificuldade de acesso, a densa cobertura vegetal e o extenso manto de intemperismo, a extracao de informacoes geologicas na regiao amazonica e uma tarefa dificil e logisticamente onerosa. Nesse contexto, dados geofisicos e de sensoriamento remoto sao essenciais para a ampliacao do conhecimento geologico dessa regiao. Esse trabalho pretende, atraves do processamento e analise de dados geofisicos aereos, terrestres e de imagens ASTER: (i) refinar a cartografia geologica da porcao sudeste da PAAF, identificando estruturas impressas em diferentes niveis da crosta, (ii) individualizar possiveis corpos graniticos ainda nao cartografados, (iii) comparar as respostas geofisicas obtidas com dados terrestres e dados aerolevantados, (iv) determinar a relacao entre os realces gamaespectrometricos e magneticos terrestres de areas-tipo no sudeste da PAAF e, (v) relacionar assinaturas gamaespectrometricas a assinaturas espectrais da vegetacao, simultaneamente indicativas de padroes associados aos depositos auriferos. O processamento e interpretacao dos dados aeromagnetometricos e aerogamaespectrometricos do projeto Juruena-Teles Pires (Fase 1), adquiridos pelo Servico Geologico Brasileiro (CPRM), permitiram a geracao de um novo mapa geologico regional da porcao leste da PAAF. Levantamentos magnetometricos e gamaespectrometricos terrestres foram realizados nas areas dos depositos do Pe Quente e Francisco como parte dessa pesquisa. Sua comparacao com os dados aereos em linhas de aquisicao equivalentes espacialmente mostra que, apesar da diferenca consideravel de escala e de amostragem, os padroes sao mantidos em ambos os tipos de levantamento. Os dados terrestres proporcionaram ainda a producao de modelos prospectivos para depositos de Au baseados em tecnicas de Analise por Principais Componentes e Logica Fuzzy. As anomalias gamaespectrometricas extraidas dos dados geofisicos foram comparadas com as caracteristicas espectrais da vegetacao e de solos/rochas extraidas do processamento de dados ASTER. O estudo demonstrou que existe uma forte correlacao espacial entre zonas ricas em K e anomalias espectrais da vegetacao, indicando que assinaturas geofisicas e geobotanicas podem ser utilizadas de maneira complementar na vetorizacao de depositos de Au na PAAF / Abstract: The Alta Floresta Gold Province (AFGP) is located in the central-southern Amazon craton between the limits of the Ventuari-Tapajos (1.95-1.8 Ga) and Rio Negro-Juruena (1.8-1.55 Ga) provinces. In its eastern segment there are more than one hundred gold deposits hosted in volcanic and plutonic rocks and concentrated along the Peru-Trairao Belt in a NW-SE direction. Included in this geologic setting, near the Peixoto de Azevedo city and the Uniao do Norte village, are the Pe Quente and Francisco deposits which are the targets of this work. Due to several factors such as restricted access, the dense vegetation and extensive weathering, the extraction of geological information in the Amazon region is not trivial. In this context geophysical data and remote sensing are essential to expand the geological knowledge of this region. This study intends, through processing and analysis of airborne geophysical data, ground geophysical data and an ASTER image of the region, (i) refine the geological mapping of the southeastern portion of the AFGP, identifying structures in different levels of the crust, (ii) individualize granitic bodies that have not yet been mapped, (iii) compare the responses of airborne and field-based geophysical data, (iv) determine the relationship between ground gamma spectrometry and magnetic data sets in the southeast of AFGP and (v) relating gamma spectrometry signatures with spectral signatures of vegetation, both indicative of patterns associated with gold deposits. Processing and interpretation of airborne gamma spectrometry and magnetic data of the Juruena-Teles Pires project (Phase 1), acquired by the Brazilian Geological Service (CPRM), allowed the generation of a new regional geological map of the eastern portion of the AFGP. Ground magnetometry and gamma spectrometry surveys were made in the areas of Pe Quente and Francisco deposits as part of this research and compared with airborne data and their response over the lines of flight, showing that even with a considerable difference of scale and sampling, these patterns are maintained in both survey types. These data resulted in the production of prospective models for Au-based deposits using Principal Component Analysis and Fuzzy Logic based techniques. Additionally, by processing an ASTER image, a correlation was found between the occurrence of gamma spectrometry anomalies with the spectral characteristics of vegetation and soil /rock, largely reflecting the strong spatial correlation between potassium-rich areas and spectral anomalies of vegetation, since this element is a essential macronutrient for the healthy development of several plants / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

Le présent travail traite de problèmes particuliers en traitement de signal soulevés par l'holographie digitale. Le premier chapitre présente l'holographie et l'holographie digitale. Le deuxième chapitre aborde le problème des artéfacts apparaissant sur le bord des hologrammes lorsque ceux-ci sont propagés numériquement. Le troisième chapitre propose une méthode automatique pour éliminer la phase de fond d'un hologramme. Le quatrième chapitre montre comment améliorer la visibilité des hologrammes en supprimant les objets diffractants. Le cinquième chapitre expose un logiciel d'aide à l'analyse des hologrammes enregistrés dans le temps. On montre la capacité du logiciel à effectuer du tracking d'objets en trois dimensions à posteriori. Le sixième chapitre traite de la reconnaissance de forme dans les hologrammes, le problème de la reconnaissance de particules micrométriques est abordé. Des conclusions et perspectives terminent le travail. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

No description available.

Measuring 3D surface geometry with precision and accuracy is an important part of many engineering and scientific tasks. 3D Scanning techniques measure surface geometry by estimating the locations of sampled surface points. In recent years, Structured-Light 3D scanners have gained significant popularity owing to their ability to produce highly accurate scans in real-time at a low cost. In this thesis we describe an approach for Structured-Light 3D scanning using a digital camera and a digital projector. We utilise the projective geometric relationships between the projector and the camera to carry out both an implicit calibration of the system and to solve for 3D structure. Our approach to geometric calibration is flexible, reliable and amenable to robust estimation. In addition, we model and account for the radiometric non-linearities in the projector such as gamma distortion. Finally, we apply a post-processing step to efficiently smooth out high-frequency surface noise while retaining the structural details. Consequently, the proposed work reduces the computational load and set-up time of a Structured-Light 3D scanner; thereby speeding up the whole scanning process while retaining the ability to generate highly accurate results. We demonstrate the accuracy of our scanning results on real-world objects of varying degrees of surface complexity. Introduction The projective geometry for a pair of pin-hole viewing devices is completely defined by their intrinsic calibration and their relative motion or extrinsic calibration in the form of matrices. For a Euclidean reconstruction, the geometry elements represented by the calibration matrices must be parameterised and estimated in some form. The use of a projector as the ‘second viewing’ device has led to numerous approaches to model and estimate its intrinsic parameters and relative motion with respect to the camera's 3D co-ordinate system. Proposed thesis work assimilates the benefits of projective geometry constructs such as Homography and the invariance of the cross-ratios to simplify the system calibration and the 3D estimation processes by an implicit modeling of the projector's intrinsic parameters and its relative motion. Though linear modeling of the projective geometry between a camera-projector view-pair captures the most essential aspects of the underlying geometry, it does not accommodate system non-linearities due to radiometric distortions of a projector device. We propose an approach that uses parametric splines to model the systematic errors introduced by radiometric non-linearities and thus correct for them. For 3D surfaces reconstructed as point-clouds, noise manifests itself as some high-frequency variations for the resulting mesh. Various pre and/or post processing techniques are proposed in the literature to model and minimize the effects of noise. We use simple bilateral filtering of the depth-map for the reconstructed surface to smoothen the surface while retaining its structural details. Modeling Projective Relations In our approach for calibrating the projective-geometric structure of a projector-camera view-pair, the frame of reference for measurements is attached to the camera. The camera is calibrated using a commonly used method. To calibrate the scanner system, one common approach is to project sinusoidal patterns onto the reference planes to generate reference phase maps. By relating the phase-information between the projector and image pixels, a dense mapping is obtained. However, this is an over-parameterisation of the calibration information. Since the reference object is a plane, we can use the projective relationships induced by a plane to implicitly calibrate the projector geometry. For the estimation of the three-dimensional structure of the imaged object, we utilise the invariance of cross-ratios along with the calibration information of two reference planes. Our formulation is also extensible to utilise more than two reference plane to compute more than one estimate of the location of an unknown surface point. Such estimates are amenable to statistical analysis which allows us to derive both the shape of an object and associate reliability scores to each estimated point location. Radiometric Correction Structured-light based 3D scanners commonly employ phase-shifted sinusoidal patterns to solve for the correspondence problem. For scanners using projective geometry between a camera and a projector, the projector's radiometric non-linearities introduce systematic errors in establishing correspondences. Such errors manifest as visual artifacts which become pronounced when fewer phase-shifted sinusoidal patterns are used. While these artifacts can be avoided by using a large number of phase-shifts, doing so also increases the acquisition time. We propose to model and rectify such systematic errors using parametric representations. Consequently, while some existing methods retain the complete reference phase maps to account for such distortions, our approach describes the deviations using a few model parameters. The proposed approach can be used to reduce the number of phase-shifted sinusoidal patterns required for codification while suppressing systematic artifacts. Additionally, our method avoids the 1D search steps that are needed when a complete reference phase map is used, thus reducing the computational load for 3D estimation. The effectiveness of our method is demonstrated with reconstruction of some geometric surfaces and a cultural figurine. Filtering Noise For a structured-light 3D scanner, various sources of noise in the environment and the devices lead to inaccuracies in estimating the codewords (phase map) for an unknown surface, during reconstruction. We examine the effects of such noise factors on our proposed methods for geometric and radiometric estimation. We present a quantitative evaluation for our proposed method by scanning the objects of known geometric properties or measures and then computing the deviations from the expected results. In addition, we evaluate the errors introduced due to inaccuracies in system calibration by computing the variance statistics from multiple estimates for the reconstructed 3D points, where each estimate is computed using a different pair of reference planes. Finally, we discuss the efficacy of certain filtering techniques in reducing the high-frequency surface noise when applied to: (a) the images of the unknown surface at a pre-processing stage, or (b) the respective phase (or depth) map at a post-processing stage. Conclusion In this thesis, we motivate the need for a procedurally simple and computationally less demanding approach for projector calibration. We present a method that uses homographies induced by a pair of reference planes to calibrate a structured-light scanner. By using the projective invariance of the cross-ratio, we solved for the 3D geometry of a scanned surface. We demonstrate the fact that 3D geometric information can be derived using our approach with accuracy on the order of 0.1 mm. Proposed method reduces the image acquisition time for calibration and the computational needs for 3D estimation. We demonstrate an approach to effectively model radiometric distortions for the projector using cubic splines. Our approach is shown to give significant improvement over the use of complete reference phase maps and its performance is comparable to that of a sate-of-the-art method, both quantitatively as well as qualitatively. In contrast with that method, proposed method is computationally less expensive, procedurally simpler and exhibits consistent performance even at relatively higher levels of noise in phase estimation. Finally, we use a simple bilateral filtering on the depth-map for the region-of-interest. Bilateral filtering provides the best trade-off between surface smoothing and the preservation of its structural details. Our filtering approach avoids computationally expensive surface normal estimation algorithms completely while improving surface fidelity.