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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Moving Object Detction In 2d And 3d Scenes

Sirtkaya, Salim 01 September 2004 (has links) (PDF)
This thesis describes the theoretical bases, development and testing of an integrated moving object detection framework in 2D and 3D scenes. The detection problem is analyzed in stationary and non-stationary camera sequences and different algorithms are developed for each case. Two methods are proposed in stationary camera sequences: background extraction followed by differencing and thresholding, and motion detection using optical flow field calculated by &ldquo / Kanade-Lucas Feature Tracker&rdquo / . For non-stationary camera sequences, different algorithms are developed based on the scene structure and camera motion characteristics. In planar scenes where the scene is flat or distant from the camera and/or when camera makes rotations only, a method is proposed that uses 2D parametric registration based on affine parameters of the dominant plane for independently moving object detection. A modified version of the 2D parametric registration approach is used when the scene is not planar but consists of a few number of planes at different depths, and camera makes translational motion. Optical flow field segmentation and sequential registration are the key points for this case. For 3D scenes, where the depth variation within the scene is high, a parallax rigidity based approach is developed for moving object detection. All these algorithms are integrated to form a unified independently moving object detector that works in stationary and non-stationary camera sequences and with different scene and camera motion structures. Optical flow field estimation and segmentation is used for this purpose.
2

Diagnostic imaging and the structure-function relationship in glaucoma

Denniss, Jonathan January 2010 (has links)
This thesis describes a series of investigations into the use of optic nerve head (ONH) imaging in primary open-angle glaucoma (POAG), and its relation to visual function. Accurate diagnosis is a key issue in POAG, particularly the difficult task of separating those with early disease from those healthy individuals who display signs of POAG. The purpose of this work is to improve diagnostic methods in glaucoma through use of ONH imaging and its relationship with visual field (VF) loss. First, the performance of a group of expert clinicians evaluating ONH photographs for glaucomatous damage was investigated. The results showed that even when their assessments are combined discrimination between eyes with and without POAG (based on VF loss) is far from perfect, highlighting the need for improvements in diagnosis. The possibility of combining structural and functional data to aid diagnosis was then considered. This requires VF loss and ONH damage to be strongly topographically related. The strength of this relationship was evaluated in 185 patients with POAG. 10,000 computer-generated maps between the ONH and VF were tested and the topographic relationship measured with each of these was compared to that using a published structure-based map. The weak topographic relationships found suggest that the application of these maps to individual patients is limited with current measures. The next chapter describes how a multispectral imaging (MSI, also called hyperspectral imaging) system was set-up for spatial evaluation of ONH oxygenation using a Beer-Lambert law model. Test-retest repeatability was tested and found to be acceptable for the purposes of the following studies. The MSI system was then used for an investigation of the relationship between ONH oxygenation and VF loss. 33 eyes of 18 patients underwent VF testing, MSI and HRT3 imaging. Superior-inferior asymmetries in VF sensitivity were compared to superior-inferior asymmetries in ONH oxygenation measured by MSI and in neuroretinal rim (NRR) area measured by HRT3. This way we take advantage of the typical progression of POAG and each eye acts as its own reference, negating the effect of a wide normal range and overlap between health and disease. This study found, for the first time, a strong association between ONH oxygenation and VF sensitivity. A re-analysis of the 33 ONH oxygenation maps was then performed to assess oxygenation only in the area of the NRR as defined by the HRT. Superior-inferior asymmetries in NRR oxygenation were then compared to superior-inferior asymmetries in VF loss, and the associations found were similarly strong. This study shows that MSI is capable of detecting areas of NRR deemed healthy tissue by structural imaging techniques, which are in fact poorly oxygenated and associated with VF defects. These findings show that NRR oxygenation measured by MSI is strongly related to VF loss. This important information complements existing technologies and may aid in the future diagnosis and management of patients with POAG.
3

Lygiavertės dozės galios laukų struktūros mažoms teritorijoms nustatymas optimalios interpoliacijos metodu / Determination of structural fields of equivalent dose rate by optimal interpolation method for small territories

Lemežis, Mindaugas 01 July 2009 (has links)
Darbe nagrinėjamas lygiavertės dozės galios (LDG) laukų struktūros virš mažų teritorijų nustatymas optimalios interpoliacijos metodu, lygiavertės dozės galios laukų struktūros pokyčiai nuo meteorologinių sąlygų. Baltijos jūros priekrantėje prie Juodkrantės atlikti LDG matavimai prie žemės paviršiaus ir vieno metro aukštyje virš jos. Matavimai atlikti 2008 m. liepos 2, 7, 10 ir 12 dienomis 63 taškuose (2,00,2) km teritorijoje esant šiaurės, pietų, rytų ir vakarų vėjo kryptims. Vidutinių dydžių ekstremalios reikšmės buvo 50 nSv/h ir 130 nSv/h. LDG laukų struktūrai nustatyti ir įvertinti buvo panaudotas optimalios interpoliacijos metodas trim atvejams – kai tyrimų teritorijoje atlikta 63, 33 ir 18 matavimų. Gautos identiškos LDG laukų struktūros. Rasta, kad naudojant tik 18 matavimo rezultatų modelyje gaunamas patenkinamas eksperimentinių ir teorinių rezultatų sutapimas, t.y. skirtumas tarp išmatuotų ir sumodeliuotų rezultatų neviršija 20  paklaidos. Nustatyta, kad esant šiaurės, pietų ir vakarų vėjo kryptims, padidėjus vėjo greičiui vidutiniškai 3 kartus, LDG sumažėja apie 8 nSv/h. Esant rytų vėjui, padidėjus vėjo greičiui 3 kartus, LDG padidėja 7 nSv/h. Darbą sudaro 3 dalys: įvadas, darbo metodai ir priemonės, išvados, literatūra. Darbo apimtis – 58 p. teksto be priedų, 46 iliustr., 1 lent., 36 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai ir publikacija, parengta spaudai. / In this work equivalent dose rate (EDR) field structures under small area was estimated by applying optimal interpolation method and EDR fields structure differences was depended on meteorological conditions. EDR measurements were made to the ground surface and one meter above it beside Juodkrante near Baltic seaside. Measurements carried out in 2008 July 2, 7, 10 and 12 days, in 63 points (2.0 x 0.2) km area then was the north, south, east and west wind direction. Extreme values of the average was 50 nSv/h ir 130 nSv/h. To determine EDR fields structure was used the optimal interpolation method in three cases – then in research area conducted 63, 33 and 18 measurements. Received identical EDR fields structure. Found that the use of only 18 measurements in the model obtained satisfactory experimental and theoretical results coincide, i.e., the difference between measured and model results in less than 20  errors. Found that, in the north, south and west wind direction, wind speed increased by an average of 3 times, EDR decreases about 8 nSv/h. In the east wind, the wind speed increased by 3 times, EDR increased 7 nSv/h / h. Structure: introduction, methods and tools of work, conclusions and suggestions, references. Thesis consist of: 58 p. text without appendixes, 46 pictures, 1 tables, 36 bibliographical entries. Appendixes and publication included.
4

Концепт «деловой человек» в китайской лингвокультуре : магистерская диссертация / The Concept of «Business Man» in Chinese Linguistic Culture

Шабунина, Е. В., Shabunina, T. V. January 2021 (has links)
В работе предпринята попытка комплексной интерпретации концепта «деловой человек» в китайской лингвокультуре сопоставительно с русской. На основании компонентного анализа деловой лексики из «Списка общеупотребительных слов коммерческого китайского языка», анализа синонимических рядов, опроса респондентов-носителей обеих лингвокультур идентифицированы понятийная и образная составляющие концепта, что позволило выстроить полевую модель, визуализирующую результаты исследования. / The paper attempts to comprehensively interpret the concept of «business man» in the Chinese linguistic culture as compared to the Russian one. Based on the component analysis of business vocabulary from the «List of the Common Business Chinese Words», on the synonymic chain analysis, and on questioning both linguistic cultures’ bearers, there are identified the conceptual and figurative components of the concept. As a result, a field model is built to visualize the results of the study.

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