Image Registration - Application in ophthalmology and ultrasonography

Registrace medicínských obrazů je v dnešních dnech široce používaná, ale zároveň je i jednou z oblastí zájmu vědeckého výzkumu. Stále nové a vylepšené zobrazovací systémy si žádají stále lepší a výkonnější metody registrace obrazu. Takovou oblastí je i kontrastní ultrazvukové zobrazování. Díky časové proměnlivému kontrastu v obraze, nízkému poměru signál/šum a specifickému šumu typu spekle je registrace ultrazvukových obrazu velice náročná. Dalším problémem je hodnocení kvality registrace. V této dizertační práci je představena metoda registrace ultrazvukových kontrastních sekvencí založena na automatické fragmentaci sekvence do podsekvencí. Následně jsou registrovány obrazy s podobnými vlastnostmi. Dále je představena nová metoda pro hodnocení kvality registrace na základě porovnání perfuzních modelů. Metoda registrace i hodnocení byla testována jak na datech získaných za pomocí fantomu, tak i na reálných pacientských datech. Výsledky pak byly porovnány se standardními metodami publikovanými v odborných článcích. Druhá menší část práce je tvořena ukázkami aplikací různých registračních metod v oftalmologii a návrhy na jejich zlepšení. Jedná se o oblast zobrazovacích systému, kde se registračních metod široce využívá. Kromě jasových registračních metod zde nachází velké uplatnění metody registrace založené na detekci významných bodů. Představené registrační přístupy tak směřují především k detekci těchto významných bodů a stanovení jejich vzájemných korespondencí v jednotlivých obrazech.Image registration is widely used in clinical practice. However image registration and its~evaluation is still challenging especially with regards to new possibilities of various modalities. One of these areas is contrast-enhanced ultrasound imaging. The time-dependent image contrast, low signal-to-noise ratio and specific speckle pattern make preprocessing and image registration difficult. In this thesis a method for registration of images in ultrasound contrast-enhanced sequences is proposed. The method is based on automatic fragmentation into image subsequences in which the images with similar characteristics are registered. The new evaluation method based on comparison of perfusion model is proposed. Registration and evaluation method was tested on a flow phantom and real patient data and compared with a standard methods proposed i literature. The second part of this thesis contains examples of application of image registration in~ophthalmology and proposition for its improvement. In this area the image registration methods are widely used, especially landmark based image registration method. In this thesis methods for landmark detection and its correspondence estimation are proposed.

Utilization of optical emission spectroscopy for analysis of chemical composition of shaft

Import 04/11/2015Tématem bakalářské práce je analýza chemického složení materiálu hnacích hřídelí v automobilovém průmyslu. Bakalářská práce je rozdělena na teoretickou a praktickou část. V teoretické části jsou hnací hřídele popsány a jsou vysvětleny jejich funkce. Dále je uvedeno jejich rozdělení na spojovací a kloubové hřídele. Hnací hřídele jsou podle složení dále děleny do třech skupin, z nichž nejvyužívanější v automobilovém průmyslu jsou hřídele ocelové. V praktické části bylo chemické složení hnacích hřídelí z automobilů Škoda Felicia, Citroen Xsara a Peugeot 206 stanoveno optickou emisní spektrometrií s doutnavým výbojem na přístroji GDA 750A, provozovaném na Katedře chemie, Fakultě metalurgie a materiálového inženýrství, VŠB-TU Ostrava.The theme of this bachelor thesis is analysis of the chemical composition of the material used in production of the drive shafts in the automobile industry. The bachelor thesis is divided into theoretical and practical parts. The theoretical part describes the drive shafts and their functions. Their division into connecting and joint drive shafts is also mentioned. According to their composition drive shafts are further divided into three groups, of which the most frequently used in the automobile industry are steel shafts. In the practical part, the chemical composition of the drive shafts in Škoda Felicia, Citroen Xsara and Peugeot 206 was determined by optical emission spectrometry with smoke discharge on the GDA 750A machine which is operated by the Department of Chemistry, Faculty of Metallurgy and Materials Engineering, at the Technical University of Ostrava.632 - Katedra materiálů a technologií pro automobilyvelmi dobř

Effect of microstructure and defects on mechanical properties of low-pressure cast Al-Si alloys

Tato diplomová práce je zaměřena na slitiny Al-Si po nízkotlakém odlévání. Teoretická část obsahuje rešerši struktury, vad a mechanických vlastností daných slitin. Experimentální část je zaměřena na analýzu licích vad daných Al-Si slitin. Hlavním úkolem bylo vyhodnocení vlivu pórovitosti na mechanické vlastnosti po nízkotlakém odlévání.This thesis is focused on Al-Si alloys after low-pressure casting. The theoretical part investigates the structure, casting defects and mechanical properties of these alloys. The experimental part is focused on analysis of casting defects of given Al-Si alloys. The main task was to evaluate the influence of porosity on mechanical properties after low-pressure casting.636 - Katedra materiálového inženýrstvívelmi dobř

Documentation and Testing Operators of XQuery Algebra

Import 05/08/2014Tato práce se zabývá operátory XQuery algebry, konkrétně algebry použité v procesoru Galax, jejich testováním a zdokumentováním. V úvodu práce je seznámení s XML a dotazovacím jazykem XQuery. Všechny jednotlivé operátory jsou detailně popsány a vysvětleny. Na závěr jsou uvedeny výsledky jednotkových testů konkrétních operátorů.This document deals with the operators of XQuery algebra, specifically algebra used in the Galax processor, their testing and documenting. At the beginning, there is an introduction to XML and query language XQuery. All individual operators are described and explained. In the conclusion, results of unit tests of specific operators can be found.460 - Katedra informatikyvýborn

DESIGN OF AN EXPERIMENTAL LASER SPECKLE CONTRAST IMAGING SYSTEM AND IMAGE EVALUATION

Laser speckle contrast imaging (LSCI) is a noninvasive method, which uses scattered light to estimate the flow of a fluid containing scatterers. Thus, it can be especially used to estimate blood flow. Laser light is randomly scattered on the tissue and this refracted light interfere with reflected light, giving birth to laser speckle noise. As the light scatters on moving red blood cells, the speckle pattern is blurred due to the exposition time. This blurring is a function of velocity which can be estimated from the degree of blur, termed as speckle contrast. Therefore, blood cells act like contrast agent, outlining blood vessels. The simple setup, unnecessary contrast agent and unharming nature are making LSCI a popular tool for studying blood flow dynamics and vascular structure. This paper presents a new, simple experimental setup and image processing methods to treat laser speckle images aiming to estimate relative blood flow and vascular structure

Arbuscular mycorrhizal fungi (AMF) root colonization dynamics of Molinia caerulea (L.) Moench. in grasslands and post-industrial sites

This is an accepted manuscript of an article published by Elsevier in Ecological Engineering on 05/08/2016, available online: https://doi-org.ezproxy.wlv.ac.uk/10.1016/j.ecoleng.2016.06.029 The accepted version of the publication may differ from the final published version.The aims of this studies were: (i) to examine the influence of heavy metal content (Zn, Cd, Pb, Fe, Cu) and other physico-chemical soil parameters on the level of root colonization of Molinia caerulea and (ii) to relate root colonisation parameters and soil variables to Molinia caerulea abundance in two contrasting habitats (grasslands and heavy metal contaminated sites). The sites differ significantly in terms of bio-available heavy metal contents, particularly Zn (34 times more than grasslands), soil texture, CaCO3, organic matter (LOI%), Mg and nitrate content. Principal Component Analysis showed the strong negative correlations between frequency of mycorrhization (F), arbuscular abundance (A%) and intensity of root cortex colonisation (M%) and concentration of bio-available Zn and Cd. Moreover, no positive correlation between root colonization of Molinia and its abundance was found. The frequency of mycorrhization of root fragments (F%) was only slightly different between these two habitats, whereas the intensity of root cortex colonisation (M%) and relative arbuscular abundance (A%) were significantly lower (3 and 4 times respectively) on the post-industrial sites. The bioavailable Zn content in the substratum of post-industrial sites was strongly negatively correlated with species richness, Shannon diversity index and Evenness. In contrast, these relationships were not statistically significant in grasslands. Based on obtained results we could draw a model of possible relationships between root colonization of Molinia, HM content and Molinia abundance on grasslands and post-industrial sites. Bioavailable Zn content in the soil is a one of main factors influencing the Molinia community diversity. In the grasslands, lower amounts of bioavailable Zn, resulted in higher species richness (R) and species diversity (H) which in turn lead to higher root colonization. On the other hand, on the post-industrial sites, the elevated bioavailable Zn content strongly decreases the plant species richness (R) and species diversity (H) and this caused the decline in root colonization parameters. The low species richness on Zn-polluted sites allowed Molinia to reach higher abundance since the competition with other species is reduced

Potential range of impact of an ecological trap network: the case of timber stacks and the Rosalia longicorn

Although the negative impact of timber stacks on populations of saproxylic beetles is a well-known phenomenon, there is relatively little data concerning the scale of this impact and its spatial aspect. Beech timber stored in the vicinity of the forest can act as an ecological trap for the Rosalia longicorn (Rosalia alpina), so in this study we have attempted to determine the spatial range of the impact of a network of timber stacks. Timber stacks in the species’ range in the study area were listed and monitored during the adult emergence period in 2014–2016. Based on published data relating to the species’ dispersal capabilities, buffers of four radii (500, 1000, 1600, 3000 m) were delineated around the stacks and the calculated ranges of potential impact. The results show that the percentage of currently known localities of the Rosalia longicorn impacted by stacks varies from 19.7 to 81.6%, depending on the assumed impact radius. The percentage of forest influenced by timber stacks was 77% for the largest-radius buffer. The overall impact of the ecological trap network is accelerated by fragmentation of the impact-free area. It was also found that forests situated close to the timber stacks where the Rosalia longicorn was recorded were older and more homogeneous in age and species composition than those around stacks where the species was absent. Such results suggest that timber stacks act as an ecological trap in the source area of the local population