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Modular system for electrical impedance tomography
Vaněk, Roman ; Mikulka, Jan
This paper presents a novel approach to an electrical impedance tomograph’s system and hardware architecture design. It delves into the strategic decisions that shaped the hardware layer of a measurement system comprising multiple units and enabling intercommunication between them. The primary objective was to develop a cost-effective method for switching a current source among numerous electrodes and measuring voltage across each with a wide dynamic range while maintaining a minimal phase shift between the channel and input of an analog-to-digital converter. The measurement system is designed and documented, serving as a valuable reference for developing new additional units.
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Training set generation system for reconstruction of electrical impedance tomography images
Zemiti, Samia ; Aloph, Clark ; Mikulka, Jan
This paper introduces an innovative approach to simulating Electrical Impedance Tomography (EIT) through MATLAB, aimed at advancing the accuracy and reliability of internal imaging using electrodes. We address the critical challenge of reconstructing interior images with high fidelity by simulating inhomogeneous mediums. Our methodology involves the generation of synthetic datasets, encompassing various inhomogeneity scenarios, followed by applying forward solutions to ascertain voltage measurements indicative of interior conductivity variations. The research emphasizes the creation of an adaptive framework capable of simulating real-world scenarios within a controlled digital environment, thereby enhancing the predictive capabilities of EIT systems in diverse applications ranging from medical imaging to industrial inspection.
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Image Reconstruction in Electrical Impedance Tomography through Multilayer Perceptron
Kouakouo Nomvussi, Serge Ayme ; Mikulka, Jan
This study introduces a novel image reconstruction algorithm designed to excel in challenging scenarios with noisy datasets. Comparative evaluations against established methods, the Total Variation technique and the Gauss-Newton algorithm, are conducted using key performance metrics including the correlation coefficient and structural similarity index. The Results demonstrate that the proposed algorithm displays variable performance in noise-free data compared to Total Variation but consistently outperforms it in the presence of noise. Furthermore, when contrasted with the Gauss-Newton algorithm, the proposed method consistently exhibits superior outcomes, particularly in scenarios involving noisy datasets, where the Gauss-Newton algorithm faces limitations. This study underscores the robustness of the proposed algorithm in noisy conditions, suggesting its potential for applications where accurate image reconstruction is critical.
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Modular system for electrical impedance tomography
Vaněk, Roman ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
Tato práce představuje nový přístup k návrhu architektury systému elektrického impedančního tomografu. Zabývá se strategickými rozhodnutími, která formovala hardwarovou vrstvu měřicího systému sestávajícího z několika jednotek a umožňujícího vzájemnou komunikaci mezi nimi. Hlavním cílem bylo vyvinout levný hardware pro přepínání zdroje proudu mezi mnoha elektrodami a měření napětí na každé z nich s širokým dynamickým rozsahem při zachování minimálního fázového posunu mezi kanálem a vstupem analogově-digitálního převodníku. Měřicí systém je navržen a zdokumentován a slouží jako cenná reference pro vývoj nových dalších jednotek. Práce popisuje hardware a firmware aktivních elektrod, klíčové části tomografu a uvádí měření ověřující správnost tohoto přístupu.
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Modernization of Tenryu Pick and Place Machine
Drška, Jan ; Szabó, Zoltán (referee) ; Mikulka, Jan (advisor)
The aim of the diploma thesis is to evaluate the current state of the machine and to propose a possible solution for the modernization of the machine and to implement selected parts. The thesis includes documentation of the original state of the Tenryu MT-5530LQ automatic machine and its documentation after modernization. In the introductory part, the theory of the automatic machine is described, this chapter is followed by a description of the function and design of the aforementioned machine. The third chapter describes and identifies the machine components that need to be replaced or repaired. The fourth chapter of this thesis contains a complete proposal for the modernization of the machine, including the possible results of the modernization. These previous chapters are followed by chapters 5, 6 and 7 where new cards for the proposed control system are described and the thesis concludes with a summary of the impact of the upgrade on the machine including options for continuing to upgrade the machine.
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Optimizing Image Reconstruction in Electrical Impedance Tomography
Dušek, Jan ; Brančík, Lubomír (referee) ; Sikora, inž Jan (referee) ; Mikulka, Jan (advisor)
Tato disertační práce pojednává o optimalizaci algoritmů pro rekonstrukci obrazu neznámé měrné vodivosti z měřených dat pořízených elektrickou impedanční tomografií. Danou problematiku zde věcně vymezuje několik různých prvků, zejména pak stručný matematický popis dopředné a inverzní úlohy řešené různými přístupy, metodika měření a pořizování dat pro rekonstrukci a přehled dostupných numerických nástrojů. Uvedenou charakteristiku rozšiřuje rozbor optimalizací parametrů modelu ovlivňujících přesnost rekonstrukce, způsoby paralelního zpracování algoritmů a souhrn dostupných zařízení pro měření tomografických dat. Na základě získaných poznatků byla navržena optimalizace parametrů matematického modelu, která umožňuje jeho velmi přesný návrh dle měřených dat. V této souvislosti dochází ke snížení nejistoty rekonstrukce rozložení konduktivity. Pro zefektivnění procesu získávání dat bylo navrženo zařízení k automatizaci tomografie s důrazem na cenovou dostupnost a snížení nejistoty měření. V oblasti tvorby numerického modelu byly dále zkoumány možnosti užití otevřených a uzavřených domén pro různé metody regularizace a hrubost sítě, a to s ohledem na velikost chyby rekonstruované konduktivity a výpočetní náročnost. Součástí práce je také paralelizace subalgoritmů rekonstrukce s využitím vícejádrové grafické karty. Předložené výsledky mají přímý vliv na snížení nejistoty rekonstrukce (optimalizací počáteční hodnoty konduktivity, rozmístění elektrod a tvarové deformace domény, regularizačních metod a typu domén) a urychlení výpočtů paralelizací algoritmů, přičemž výzkum byl podpořen vlastním návrhem jednotky pro automatizaci tomografie.
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Filtering methods for NMR measurements
Nezhyba, Jiří ; Mikulka, Jan (referee) ; Gescheidtová, Eva (advisor)
This master’s thesis deals with the wavelet transform and its use in processing and removing noise from images acquired by nuclear magnetic resonance. It defines fundamental terms for this work as mother wavelet or thresholding. Above all, it describes the principle of wavelet transform, thresholding techniques and criteria for evaluating the effectiveness of filtration. It describes the relation between wavelet transforms and digital filter banks. The experimental section describes the designed filtering method for removing noise from an image captured by the technique of nuclear magnetic resonance. We applied to different kinds of mother wavelets. Evaluation of the effectiveness of filtering was performed using the signal to noise ratio, relative contrast and the steepness of the intensity changes in signal intensity. It also discusses the comparison of properties of the image and selecting the mother wavelets based on image characteristics. Images were compared in terms of a histogram, cumulative histogram, k-space and the difference image.
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Evaluation of the Financial Situation in the Firm and Proposals to its Improvement
Gelnar, Jiří ; Mikulka, Jan (referee) ; Bartoš, Vojtěch (advisor)
Bachelor's thesis is focused on the evaluation of the financial position of the company Baťa, a.s. during the four years between 2005 and 2008. The results are taken from the company's financial statements for the period under consideration. The first part of the thesis is based on clear theory, which is important to the overall understanding of the financial position. Then secondly we introduce information about the firm and its neighbourhood in the form of basic factual information, and provide a SWOT analysis, a Porter's model and a 4P marketing mix analysis. In the third part of the thesis we provide information on the current implemented financial analysis position of the company and then most importantly in the final part there are proposals to help improve the financial position of the company on the basis of the information provided.
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Processing of X-Ray images in studying jawbone diseases
Kabrda, Miroslav ; Šmirg, Ondřej (referee) ; Mikulka, Jan (advisor)
The subject of this thesis is a method proposed for automated evaluation of the parameters of X-ray of cystic disorders in human jawbones. The main problem in medical diagnostic is the low repeatability due to the subjective evaluation of images without using a tool for image processing. In this thesis are described the basic steps of image processing, various methods of image segmentation and chosen segmentation method live-wire. Selected segments were processed in the ImageJ Java environment. In the cystic regions their basic statistical and shape properties were evaluated. The obtained values were used for learning the classification model (decision tree) in the environment RapidMiner. This model was used to create a plug-in for automatic classification of the type of cysts in the program ImageJ.
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