Many mathematical models have been designed to remove noise from images. Most of them focus on grey value images with additive artificial noise. Only very few specifically target natural color photos taken by a digital camera with real noise. Noise in natural color photos have special characteristics that are substantially different from those that have been added artificially. In this thesis previous denoising models are reviewed. We analyze the strengths and weakness of existing denoising models by showing where they perform well and where they don't. We put special focus on two models: The steering kernel regression model and the non-local model. For Kernel Regression model, an adaptive bilateral filter is introduced as complementary to enhance it. Also a non-local bilateral filter is proposed as an application of the idea of non-local means filter. Then the idea of cross-channel denoising is proposed in this thesis. It is effective in denoising monochromatic images by understanding the characteristics of digital noise in natural color images. A non-traditional color space is also introduced specifically for this purpose. The cross-channel paradigm can be applied to most of the exisiting models to greatly improve their performance for denoising natural color images.

Contemporary digital imaging practice has largely adopted the visual characteristics of its closest mediatic relative, the analogue photograph, In this regard, new media theorist Lev Manovich observes that "Computer software does not produce such images by default. The paradox of digital visual culture is that although all imaging is becoming computer-based, the dominance of photographic and cinematic imagery is becoming even stronger. But rather than being a direct, "natural" result of photo and film technology, these images are constructed on computers" (Manovich 2001: 179), Manovich articulates the disjuncture between the technical processes involved in the digital image creation process and the visual characteristics of the final digital image with its replication of the visual qualities of the analogue photograph. This research addresses this notion further by exploring the following. What are the defining technical features of these computer-based imaging processes? Could these technical features be used as a basis in developing an alternative aesthetic for the digital image? Why is there a reticence to visually acknowledge these technical features in contemporary digital imaging practice? Are there historic mediated precedents where the inherent technical features of the medium are visually acknowledged in the production of imagery? If these defining technical features of the digital imaging process were visually acknowledged in this image creation process, what would be the outcome? The studio practice component of the research served as a foundation for the author's artistic and aesthetic development where the intent was to investigate and highlight four technical qualities of the digital image identified through the case studies of three digital artists, and other secondary sources, These technical qualities include: the composite RGB colour system of the digital image as it appears on screen; the pixellated microstructure of the digital image; the luminosity of the digital image as it appears on a computer monitor, and the underlying numeric and (ASCII based) alphanumeric codes of the image file which enables that most defining feature of the image file, that of programmability, Based on research in the visualization of these numeric and alphanumeric codes, digital images of bacteria produced through the use of the scanning electron microscope, were chosen as image content for an experimental body of work to draw the conceptual link between these numeric and alphanumeric codes of the image file and the coded genetic sequence of an individual bacterial entity.

Photojournalism in South Africa is in the process of undergoing a shift from an analogue past to a fully digital future. This shift to digital has already been completed by many of the newspapers in the United States of America and Europe, and the new technology is seen to have made fundamental differences in the way that journalists do their job. This thesis attempts to explore the differences brought about, as well as the problems experienced by the photographic department at the Sowetan newspaper as a result of the shift to digital. How the development of technology has affected the photojournalist throughout is focused upon in a brief history of photojournalism and examples of how technology has shaped different aspects of journalism in both a positive and negative manner is considered. Exactly what digital photography is, how it has been integrated into American Photographic departments and the changes that the new technology has prompted are also explained. The manipulation of images in the past as well as the relative ease of digital manipulation are covered and concerns are raised about the future implications of digital manipulation. By conductlng participant observation and holding interviews, research data was compiled which allowed conclusions to be drawn about the impact that the shift to digital had had on the Sowetan photographic department. Intentional and unintentional consequences were expected and revealed in the research. The job of the photojournalist and photographic editor was found to have changed but perhaps not as dramatically as expected. Third world factors such as crime, poverty and lack of education were discovered to have resulted in problems that differed noticeably from those experienced by American and European photographic departments. Some expected difficulties were not experienced at all, while other major obstacles, specifically the repairs that must constantly be made to the digital cameras, continue to hamper the operations of the new digital department. Some understanding of the problems that might be encountered by future photojournalism departments that are considering making the shift to digital are arrived at, in the hope that they may be foreseen and overcome.

The quality of a digital image pipeline relies greatly on its color reproduction which should at a minimum handle the color constancy, and the final judgment of the excellence of the pipeline is made through subjective observations by humans. This dissertation addresses a few topics surrounding the color processing of digital image pipelines from a practical point of view. Color processing fundamentals will be discussed in the beginning to form a background understanding for the topics that follow.A memory color assisted illuminant estimation algorithm is then introduced after a review of memory colors and some modeling techniques. Spectral sensitivity of the camera is required by many color constancy algorithms but such data is often not readily available. To tackle this problem, an alternative method to the spectral characterization for color constancy parameter calibration is proposed. Hue control in color reproduction can be of great importance especially when memory colors are concerned. A hue constrained matrix optimization algorithm is introduced to address this issue, followed by a psychophysical study to systematically arrive at a recommendation for the optimized preferred color reproduction. At the end, a color constancy algorithm for high dynamic range scenes observing multiple illuminants is proposed. / Graduation date: 2012

Orientador: Luise Weiss / A biblioteca do IA acompanha 2 DVD-R / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Artes / Made available in DSpace on 2018-08-19T02:45:00Z (GMT). No. of bitstreams: 1 Cardoso_SilviaHelenadosSantos_D.pdf: 204143936 bytes, checksum: 8684d797a1436e3233a9c041032a67bb (MD5) Previous issue date: 2011 / Resumo: Estrada, Paisagem e Capim - Fotografias e Relatos no Jalapão é uma pesquisa em Poética Visual constituída por viagens - como deslocamento e experiência estética - ao cerrado jalapoeiro, no interior do Estado do Tocantins. A fotografia digital e as anotações se constituem como expressão e desenvolvimento do percurso processual do trabalho realizado. As referências teóricas e visuais contaram com a Antropologia como essência, metodologia e inserção no campo de pesquisa e a Arte como espaço de reflexão e criação para o caminho poético. Diferentes questionamentos surgiram ao longo do desenvolvimento do fazer artístico e acabaram por delimitar o trabalho. Nesta pesquisa, arte, natureza e cultura tornam-se pares no processo de registro e percepção da intuição criativa fotográfica, enfatizando assim, o caráter de "work in progress". Um Livro de Fotografias e um DVD sonorizado com 170 imagens são apresentados como processo e resultado do trabalho poético / Abstract: Road, Landscape and Grass - Photographs and Reports in the Jalapão is a research in Poetic Visual consisting of travels - such as displacement and aesthetic experience - to the brazilian savannah, in the State of Tocantins/BR. The digital photography and the written summary notes are as expression and development of the proceedings of the visual work done. The theoretical and visual references counted with the Anthropology as well as essence, methodology and insertion in the field of research, and the Art to be a space for reflection and creation for the poetic way. Different questions have arisen in the course of the development of artistic making and ultimately define the work. In this research, art, nature and culture have become parts in the process of registration and perception of the creative intuition photographic, emphasizing the character of "work in progress". A book of photographs and a DVD with sound and 170 images are presented as a process and outcome of the research poetic / Doutorado / Artes Visuais / Doutor em Artes

Tiene como objetivo principal analizar las diversas estrategias implementadas por los usuarios al momento de producir y compartir selfies en las redes sociales y a su vez, comprender cómo los selfies contribuyen a la construcción y reconstrucción de sus identidades virtuales. Buscamos categorizar también los motivos fundamentales por las cuales los individuos incurren en estas prácticas, además de documentar la evolución de las tecnologías de la información y su repercusión en los usuarios. / Tesis

The purpose of this thesis is to create a high school digital photography curriculum that is relevant to real world application and would enable high school students to enter the work force with marketable skills or go on to post secondary education with advanced knowledge in the field of digital imaging.

Polymeric composites reinforced with bio-materials have advantages over composites with synthetic reinforcements. Bio-based composites use low-cost and renewable reinforcements, have nonabrasive properties for machining, have improved damping characteristics, and have potential for energy recycling. However, the limited use of bio-based composites is because their mechanical properties are typically much lower than those of synthetic composites. The objective of this study was to combine state-of-the-art imaging tools with emerging numerical modeling methods for an integrated, multi-level characterization of bio-based reinforcements and their composites. Digital photography (2D) will allow collection of full-field digital images of the surface of sample composites, which will be used for characterization of the morphological structure of fillers (copper wire or wood particle) and of model composites. Mechanical experiments (tension load) on isolated fillers and on model composites will allow imaging of the deformed material. By correlating relative positions of thousands of surface features between consecutive images, digital image correlation (DIC) algorithms can be used to map surface deformation fields and calculate surface strain fields. Digital imaging methods can only record deformations and strains. The interpretation of those strains in terms of material properties, such as position-dependent modulus of a heterogeneous composite material, requires simultaneous modeling. The modeling must use morphology-based methods that can handle anisotropy, heterogeneity, and the complex structure of bio-based composites such as wood plastic composites. This research used the material point method (MPM) as a modeling tool. MPM is a particle-based, meshless method for solving problems in computational mechanics. The crucial advantage of MPM over other methods is the relative ease of translating pixels from digital images into material points in the analysis. Thus digital images (2D) used in our experiments were used as direct input to the MPM software, so that the actual morphologies, rather than idealized geometries, were modeled. This procedure removes typical uncertainties connected with idealization of the internal features of modeled materials. It also removes variability of specimen to specimen due to morphology variations. Full-field imaging techniques and computer modeling methods for analysis of complex materials have developed independently. This research Coupled imaging and modeling and used inverse problem methodology for studying bio-particulate composites. The potential of coupling experiments with morphology-based modeling is a relatively new area. This work studied the morphology and mechanical properties of copper wire (for validation experiments) and wood particles used for reinforcement in polymer composites. The goal was to determine the in situ mechanical and interfacial properties of copper wire and then wood particles. By comparison of DIC results to MPM, the conclusion is MPM simulation works well by simulating 3D composite structure and using Matlab software to do qualitative and quantitative comparisons. Copper validation tests showed that copper wire is too stiff compared to polymer such that the inclusion modulus had low effect on the surface strains (DIC experimental results). Wood particle worked better because modulus of wood is much lower than copper. By qualitative comparison of the wood particle specimens, we could deduce that the in situ properties of wood particles are lower than bulk wood. Quantitative analysis concentrated on small area and got more exact results. In a 90 degree particle quantitative study, MPM simulations were shown to be capable of tracking the structure of wood particle plastic, which involved failure. The entire approach, however, is not very robust. We can get some results for mechanical properties, but it does not seem possible to extract all anisotropic properties from a few DIC tests, as some researcher have suggested. / Graduation date: 2012

There is no abstract available for this thesis. / Department of Journalism

CNPq / Este trabalho tem por objetivo apresentar uma nova proposta aos algoritmos de Demosaicing existentes, utilizando uma abordagem mais flexível quanto ao uso do Color filter array (CFA) em imagens coloridas de único sensor. O algoritmo proposto tem como base a estrutura de problemas inversos, cujo funcionamento utiliza um modelo de operação matriz-vetor que é adaptável ao CFA empregado. A partir deste conceito, o algoritmo trata o problema de Demosaicing como o de minimização de função custo, com um termo referente à dependência da estimativa com os dados obtidos e com o modelo de captura, o outro termo é relacionado aos conhecimentos observados em imagens que podem ser explorados para uma estimativa mais precisa, tal elemento é chamado de Prior. A proposta estabelecida tem como base algoritmos de regularização com foco na alta correlação presente entre os canais de cor (R, G e B), e na suavidade local de regiões uniformes, essa base formaliza o Prior empregado no trabalho. A minimização da proposta é atingida iterativamente através do IRLS-CG, que é a combinação de dois algoritmos de minimização eficientes, que apresenta rápidas respostas, e a capacidade de trabalhar com a norma L1 em conjunto com a norma L2. Com o intuito de atestar a qualidade do algoritmo proposto, foi elaborado um experimento em que o mesmo foi testado com diferentes CFAs e em situação com ruído gaussiano de 35dB e sem ruído algum em imagens da base de dados da Kodak, e os resultados comparados com algoritmos do estado-da-arte, no qual o desempenho da proposta apresentou resultados excelentes, inclusive em CFAs que destoam do padrão Bayer, que é o mais comumente usado na atualidade. / This research presents a new proposal to Demosaicing algorithms, using a more flexible approach to deal with the Color filter array (CFA) in single sensor color imaging. The proposed algorithm is structured in the inverse problems model, whose functions employ a CFA adaptive matrix-vector operational model. From this concept, the Demosaicing problem is treated as a cost function minimization with two terms, one referring to the dependence between the estimation and the data provided by the acquisition model, and other term related to features observed in images, which can be explored to form a more precise estimation, this last term is known as Prior. The established proposal is applied in regularization algorithms with focus on the high correlation among color channels (R, G, and B), and in the local smoothness of uniform regions. Both characteristics organize the Prior employed in this work. The minimization proposed is iteratively achieved through IRLS-CG, which is the combination of two efficient minimization algorithms, that presents quick responses, and the capacity to deal with L1 and L2 norm at the same time. The quality of the proposed algorithm is verified in an experiment in which varous CFA were used and a situation with 35dB gaussian noise and another one with no noise applied to the Kodak dataset, and the results were compared with state-of-the-art algorithms, in which the performance of the proposed Prior showed excellent results, including when the CFA is different from Bayer’s, which is the most commonly used pattern.