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ABSTRACT The amount of information contained in an image is often much more than is necessary. Computer generated images will always be constrained by the computer's resources or the time allowed for generation. To reduce the quantity of data in a picture while preserving its apparent quality can require complex filtering of the image data. This paper presents an algorithm for reducing data in polygon based images, using different filtering techniques that take advantage of a priori knowledge as to the images' content. One technique uses a novel implementation of vertex elimination. By passing the image through a sequence of controllable filtering stages, the image is segmented into homogeneous regions, simplified, then reassembled. The amount of data representing the picture is reduced considerably while a high degree of image quality is maintained. The effects of the different filtering stages will be analyzed with regard to data reduction and picture quality as it relates to flight simulation imagery. Numeri­ cal results are included in the analysis. Further applications of the algorithm are discussed as well.

The aim of the present work is to experimentally study the dynamics of the formation of a fiber network formed from the filtration of a fiber suspension. This is relevant for all industrial applications (e.g. papermaking, productions of composite material, etc.) where a suspension of fibers has to flow through narrow gaps, and the quality of the product depends on the distribution of mass and orientation of the fibers. To study the dynamics of network formation, we developed an experimental setup where the filtration of a fiber suspension through a semi-permeable screen can be studied. In the setup, both the fluid and the solid phase can be visualized. The focus of the present thesis is to study the fluid flow generated during the filtration. Index of refraction matching, image processing and particle image velocimetry have been used to measure the velocity field in the proximity of the resulting fiber network. Experiments with varying fiber length and filtration velocity have been performed. The disturbances generated by the screen and the forming network was found to be confined in a region (boundary region), whose extension varies with time: first, after the formation of the first fiber layers, the extent of the boundary region increases; at later times, the boundary region is thinner. The extent appears to be correlated to the gap size either of the screen (at very early times) or of the fiber network, but independent of the filtration velocity. Fluctuations on a scale larger than a fiber length are also observed during the filtration process. These fluctuations are found to be correlated to the nondimensional number Se that relates the sedimentation velocity of a fiber to the filtration velocity. The governing non-dimensional parameters are derived from the equations. The parameters are used to relate the experimental observations to the dewatering process in papermaking. / QC 20101103

No / X-radiography of textile objects reveals hidden features as well as unexpected components and materials. This non-destructive technique throws light on construction, manufacturing techniques, use, wear, repair, patterns of decay and dating. X-radiography improves artefact documentation and interpretation as well as guiding conservation approaches by enhancing understanding. This book explores techniques for X-raying textiles. It describes approaches to image interpretation and explains how, through digitisation and digital image manipulation, maximum information can be realised. Case studies include archaeological, ecclesiastical and ethnographic textiles, items of dress and accessories, upholstery, quilts, embroideries, dolls and toys. Museum professionals will find this stimulating book an essential guide for developing their own practice or commissioning textile X-radiographs.

Manual fracture mapping in tunnels, caverns, mines or other underground spaces is a time intensive and sometimes dangerous process. A system that can automate this task could minimize human exposure to rockfalls, rockbursts or instabilities and facilitate the use of new methods of data visualization such as virtual environments. This research was undertaken to develop VTtrace; a semi-automatic fracture mapping algorithm based on image processing and analysis techniques. Images of a rock exposure surface are made using a "prosumer" grade digital camera. The grayscale images are preprocessed to remove color information and any noise or distortion. The smoothed images are converted into binary images. The binary images are then thinned to extract the fracture map. The fractures are then separated and stored as different images. Fracture properties such as the length, width, orientation and large-scale roughness are determined using photogrammetric techniques. Results from test images shows the VTtrace is effective in extracting rock discontinuity traces. Additional enhancements to the program are proposed to allow feature attributes from the three-dimensional surface to be determined. / Master of Science

Recent research discussed the development of image processing tools as a part of the quality control framework in manufacturing environments. This research could be divided into two image-based fault detection approaches: 1) MVS; and 2) MVS and control charts. Despite the intensive research in both groups, there is a disconnect between research and the actual needs on the shop-floor. This disconnect is mainly attributed to the following: • The literature for the first category has mainly focused on improving fault detection accuracy through the use of special setups without considering its impact on the manufacturing process. Therefore, many of these methods have not been utilized by industry, and these tools lack the capability of using images already present on the shop floor. • The studies presented on the second category have been mainly developed in isolation. In addition, most of these studies have focused more on introducing the concept of utilizing control charts on image data rather than tackling specific industry problems. • In this thesis, these limitations are investigated and are disseminated to the research community through two different journal papers. In the first paper, it was shown that a face-recognition tool could be successfully used to detect faults in real-time in stamped processes, where the changes in image lighting conditions and part location were allowed to emulate actual manufacturing environments. On the other hand, the second paper reviewed the literature on image-based control charts and suggested recommendations for future research. / Master of Science

In contrast to composites and woven fabrics, nonwoven materials have a unique web structure, which is composed of randomly oriented fibres bonded in a pattern by mechanical, thermal or chemical techniques. The type of nonwovens studied in this research is a thermally bonded one with polymer-based bicomponent fibres. Such fibres have a core/sheath structure with outer layer (sheath) having a lower melting temperature than that of the core. In thermal bonding of such fibres, as the hot calender with an engraved pattern contacts the fibrous web, bond points are formed thanks to melting of the sheath material. Molten sheath material acts as an adhesive while core parts of the fibres remain fully intact in the bond points. On the other hand, web regions, which are not in contact with the hot engraved pattern, remain unaffected and form the fibre matrix that acts as a link between bond points. With two distinct regions, namely, bond points and fibre matrix, with different structures, nonwovens exhibit a unique deformation behaviour. This research aims to analyse the complex mechanical behaviour of thermally bonded bicomponent fibre nonwoven materials using a combination of experimental and numerical methods. A novel approach is introduced in the thesis to predict the complex mechanical behaviour of thermally bonded bicomponent fibre nonwovens under various threedimensional time-dependent loading conditions. Development of the approach starts with experimental studies on thermally bonded bicomponent fibre nonwovens to achieve a better understating of their complex deformation characteristics. Mechanical performance of single bicomponent fibres is investigated with tensile and relaxation tests since they are the basic constituents of nonwoven fabrics. The fabric microstructure, which is one of the most important factors affecting its mechanical behaviour, is examined with scanning electron microscopy and X-ray micro computed tomography techniques. At the final part of experimental studies, mechanical response of thermally bonded bicomponent fibre nonwovens is characterised with several mechanical tests. (Continues...).

<p>Predmet disertacije jeste optimizacija digitalne slike kada<br />ograničenje nije vezano za način reprodukcije već za samog posmatrača,<br />odnosno optimizacija opaženog kvaliteta digitalne slike od strane<br />osoba sa poremećajima viđenja boja. Predloženi model optimizacije<br />slike poboljšava distinkciju boja i opseg boja slike za korisnike sa<br />različitim težinama poremećaja viđenja boja uz očuvanje prirodnosti<br />slike. Metodološki okvir ispitivanja, koji uključuje kvantitativnu<br />analizu računarskih simulacija, analizu eye-tracking podataka i<br />subjektivno ocenjivanje poboljšanja opaženog kvaliteta test slika,<br />daje sistematičnu i pouzdanu verifikaciju efektnosti predloženih<br />metoda adaptacije boja slike.</p> / <p>The subject of the thesis was the digital image optimization when an<br />observer represents the main image reproduction limitation or, in other<br />words, the optimization of the perceived image quality by individuals with<br />colour vision deficiencies. The proposed image optimization model enhances<br />colour distinction and gamut for users with different severities of colourblindness<br />while preserving the image naturalness. The used methodological<br />framework, including a quantitative analysis of computer simulations, an<br />analysis of eye-tracking data and a subjective evaluation of the perceived<br />image quality, provides systematic and reliable effectiveness verification of<br />the proposed colour adaptation methods.</p>

The objective of this project was to contribute to deepen the piece of knowledge about swi¬rling movement of the water in the hydraulic power plants’ water intakes, especially in case of the Swirl Turbine. The vortexes mostly occur near outflow holes in the bottom or walls of water tanks. Collectively they are called inflow vortices. According to the form they take they can be divided into four main categories. By the model research on hydraulic power plants’ inflow it is generally concerned on determination enough infallible conditions, under which the pulling-in of the air by a vortex into an inflow does not happen. For this purpose has been in the Fluid engineering laboratory projected and realized an experimental device enabling observation of creation, spread and extinction of the inflow vortices.

A cultura de soja desempenha um papel importante na economia nacional, por isso seria importante o estabelecimento de métodos de testes precisos que pudessem auxiliar na determinação da qualidade das sementes para definição do destino certo de um lote, direcionando-o para plantio ou alimentação. Testes de vigor são testes que levam em consideração a relação entre a semente e o ambiente de semeadura e complementam os resultados de testes de germinação, descrevendo o potencial que um lote de sementes possui para o desenvolvimento de plântulas normais sob um amplo conjunto de condições ambientais. O método clássico para avaliação da germinação e do vigor de sementes baseia-se na inspeção visual das plântulas após um período de germinação sendo um processo demorado e subjetivo, assim, neste trabalho é proposta uma novo método para automatizar a avaliação da germinação e do vigor de um lote de sementes de soja com base no desenvolvimento das plântulas, por meio da análise de imagens digitais. As imagens deste experimento são capturadas por um scanner e depois são submetidas a procedimentos para que se possam extrair as características relevantes para calcular o vigor. Foram avaliados três métodos para segmentar as imagens baseados nos modelos de cor RGB, HSV e imagens geradas pelo resultado de operações matemáticas entre canais dos dois modelos, foram testadas duas metodologias para separar o cotilédone da raiz em plântulas, sendo uma baseada no detector de bordas Canny e outra no detector de cantos SUSAN. Para calcular o índice de vigor, foram utilizadas equações propostas por outro Sako e também foi desenvolvida uma equação baseada no processo de irrigação de solo para análise de uniformidade do comprimento de plântulas. Como resultados obtiveram-se uma média de 91% de cotilédones removidos corretamente das imagens e uma nova equação que melhor representa a uniformidade e elimina a subjetividade humana. / Soybean plays an important role in the national economy, so it would be important to establish accurate methods that can assist in determining the quality of seeds to define the right destination to the seed lots, directing it to planting or feeding. Vigor tests are tests that consider the relationship between the environment and seed and complement germination tests results, describing the potential that seed lot has for developing normal seedlings under a wide range of environmental conditions. The classic methods to evaluate seed germination and vigor are based in visual inspection after a germination period, taking much time and it is a subjective task, thus this paper purposes a new method to automatize seed germination and vigor assessment based on seedlings growth using digital images analysis. Images for this experiment are captured by a scanner and then they are submitted to procedures which can extract relevant characteristics to calculate vigor and germination. Three different methods were tested to segmentate images using RGB and HSV color models and images created by results of mathematical operations among arrays of this two color models, having two methodologies to cotyledon from root in seedlings, being one based on Canny edge detector and another based in SUSAN corner detector. To calculate vigor index were tested equations purposed by another authors and also purposes using an equation developed to soil irrigation adapted for assess length uniformity of seedlings. As results we obtained an average of 91% of cotyledons removed properly from images and a new equation that best represents the uniformity of a seed lot and eliminates human subjetivity.