Thesis (DTech(Business Informatics))--Cape Technikon, Cape Town, 1997 / Modem applications in computer graphics and telecommunications command high performance filtering and smoothing to be implemented. The recent development of a new class of max-min selectors for digital image processing is investigated with special emphasis on the practical implications for hardware and software design.

Orientador: Pelódidas Cypriano de Oliveira / Banca: Maria Silvia Barros de Held / Banca: Issao Minami / Resumo: A pesquisa que apresento, sob forma de Trabalho Equivalente, investiga os procedimentos artísticos envolvidos na produção de um portfólio, a partir a partir do estudo de alguns conjuntos de trabalhos plásticos produzidos ou orientados por mim. A primeira etapa do processo consistiu em analisar os dez anos iniciais de minha produção artística, partindo das primeiras composições, realizadas em 1996, e chegando ate as pinturas mais recentes executadas durante o primeiro ano de mestrado em 2006. Organizei os trabalhos mais significativos, cronologicamente, em quatro portfolios que traduzem os interesses, as necessidades e as expectativas de períodos específicos. O segundo momento da pesquisa foi dedicado ao relado de algumas das minhas experiências no ensino de arte, ocorridas nos anos de 2006 e 2007, através das quais tive a oportunidade de orientar a produção de uma série de visualidades. Como produto final dessa sistematização propus a elaboração de um novo portfólio que sintetiza o meu percurso como artista visual e como professora na área de Artes. As imagens presentes neste relatório circunstanciado não desempenham função ilustrativa; elas constituem o verdadeiro substrato desta reflexão comunicada, essencialmente, através da linguagem visual. / Abstract: The research that I present, in a form of Equivalent Work, investigates the artistic procedures envolved in the production of a portfolio from the study of some plastic art work set produced of orientated by me. The first stage of the process consisted in analyse the first ten years of my artistic production starting from ghe first composition, realizead in 1996 and finishid until the most recent paitings executed durint the first year of the Visual Art Masters, in 2006. I organized the most significant works chronologically, in four portfolios that express the intersts, needs and expectationsa of specific periods. The second stage was dedicated the report of some art teaching experiences of mine, occured in the years of 2006 and 2007, through them I had the opportunity to orientate the production of visualitics. As the result of this system I propused an elaboration of a new portfolio that systhetizes my trajectory as a visual and as a teacher in the art area. The present imges in the written repor don't represent illustrative function; they compose the real abstracat of this communicated reflection essentiallly through the visual language. / Mestre

Made available in DSpace on 2014-10-09T12:30:29Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:48Z (GMT). No. of bitstreams: 1 00044.pdf: 2049945 bytes, checksum: bb1f86f542894839854874ab808f5f4f (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Energia Atomica - IEA

Many applications of image processing require the initial segmentation of the image by means of grey-level thresholding. In this thesis, the problems of automatic threshold selection and evaluation are addressed in order to find a universally applicable thresholding method. Three previously proposed threshold selection techniques are investigated, and two new methods are introduced. The results of applying these methods to several different images are evaluated using two threshold evaluation techniques, one subjective and one quantitative. It is found that no threshold selection technique is universally acceptable, as different methods work best with different images and applications

The question to be answered by this research is how would a fine artist working in South Africa, identify and use the correct digital printing techniques to accurately print their work?

Bombardment of intact cells and tissue with DNA-coated microprojectiles represents a novel approach to the genetic transformation of biological material. In this thesis, a gas propulsion particle gun is developed for such a purpose. The particle gun utilises gas dynamics to control particle velocity and spread, thereby enabling optimisation of transformation efficiencies for varying types of target material. The dynamics associated with particle acceleration are shown to relate to transient, shock tube flow. Measurements from schlieren high-speed video photographs of the shock structure of an underexpanded jet demonstrate good agreement with empirical correlations of previous researchers; pitot tube measurements of the nozzle exit Mach number are made and shown to be in good agreement with theoretical contact surface velocities. A novel optical particle velocimeter is used to measure particle time-offlight between axial locations in the system's target chamber, providing a consistent, distance-averaged measurement of particle velocities. Particle velocities are measured for a range of system pressure ratios and driver gases. Variation in particle velocities is seen to be similar to theoretical variation in contact surface velocities. Analytical theory is used to predict small gas-particle velocity lag. Particle velocities with helium as a driver gas are shown to be considerably higher than those with air. High speed video recording of chalk particles exiting the nozzle is used to visualise the spatial and temporal variation in particle spread as a function of nozzle pressure ratio. This technique demonstrates that particle spread increases with increasing nozzle pressure ratio, as gas dynamics theory indicates. Conditions for bombardment of maize suspension cells are experimentally optimised. Significant rates of transient genetic expression are achieved with both air and helium as driver gases. High levels of transient genetic expression are also found with bombardment of maize coleoptiles and the leaves of various dicot species. Transformation efficiencies for bombardment of HL60 human leukaemia cells show dramatic increases over efficiencies seen with conventional techniques not involving cell bombardment. For other cell types the gas propulsion device described here appears to give rates of transient genetic expression similar to those reported for commercial systems using microprojectiles. Other data for the performance of such systems are too limited at present to allow comparisons of controllability and reproducibility of bombardment efficiency.

No description available.

M.Ing. / This dissertation proposes a marker-free visual based interface device to be used with menu driven systems. This system, called HandsFree, uses the Graphics Processing Unit (GPU) together with Shader technology to perform the image processing. HandsFree makes use of a web camera to gain user input without requiring elementary computer skills. Background subtraction was used to extract user input from the images. The problems usually obtained with background subtraction were overcome by using an averaging technique. Test results proved HandsFree to be robust against different coloured backgrounds and skin tones, different lighting intensity and sudden change in lighting intensity.

The production of good quality radiographs is a complex process, given the high level of image quality required (Sniureviciute & Adliene, 2005: 260). Exposure of patients to x-rays, a factor in the production of quality radiographs also entails a risk of radiation injury. In 2006, computerized radiography (CR) was introduced at The Nairobi Hospital to try and reduce the film reject rate, decrease repeats, reduce financial costs of consumables like x-ray films and processing chemicals. However, to date, no formal film reject analysis has been conducted at The Nairobi Hospital. Four years after the incorporation of CR, there is apparently, still a significant number of film rejects, implying operational costs may still be high. The cause of film rejects and overall reject cost is not known. This has led to the research question: “Has the film reject rate in the A & E x-ray unit at The Nairobi Hospital reduced following incorporation of CR?” A quantitative, retrospective, descriptive study involving a reject film analysis of rejected radiographs in the Accident and Emergency (A&E) x-ray unit in the Nairobi Hospital, Kenya was conducted. The researcher collected data for a period of 6 months between 2/12/07 and 28/05/08 using a purpose-designed data collection form. All rejected x-ray films during the study period were included. Capture and analysis of the collected data was completed by the researcher using SPSS 10 and EPINFO computer packages. Permission to conduct the study was obtained from The Nairobi Hospital Education Committee and due consideration to patient and radiographer confidentiality was maintained throughout the study. A total of 851(2.5 percent) x-ray films were collected during the study period. Four hundred and fourteen (2.6 percent) radiographs and 437 (2.5 percent) radiographs were rejected prior to and after the incorporation of CR respectively. Chest radiographs were the most frequently rejected accounting for 277(66.9 percent) and 123 (28.1 percent) prior to and after the incorporation of CR respectively. The most frequently rejected film size was 35x35cm prior to the incorporation of CR (61.6 percent) and 26x35cm film size after the incorporation of CR (91.3 percent). The most frequent cause of film rejects was radiographer causes both prior to and after the incorporation of CR accounting for 496 (58.3 percent). The film reject rate did not significantly reduce after the incorporation of CR, suggesting that there are other factors which contribute to reject rate, other than CR. The study also shows that higher film consumption does not necessarily lead to high reject rates. The percentage value on annual rejects did not change after the incorporation of CR and a demonstrated increase in the annual cost of purchasing x-ray films was attributed to an increase in annual consumption after the incorporation of CR, and also to the higher cost of digital x-ray films. Despite some identified limitations to this study, some recommendations, which included conduction of regular reject analyses and regular continuing professional development with respect to radiographic technique amongst others, were suggested.

No description available.