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Ultrasound Image Sequences Segmentation
Kořínek, Peter ; Jiřík, Radovan (referee) ; Mézl, Martin (advisor)
When we scan image data by ultrasound, we have a little information of displayed scene. For understanding content of the image we try to separate the observed objects of interest from the background. Obtaining information of these objects is called a process called segmentation. This work is focused on the segmentation of ultrasound image sequences using geometric active contours solved by the method of level sets. For better representation is also dealing with image preprocessing. The result is an implementation of segmentation methods on simulated and real data.
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Registration of MR Images and Histological Sections
Martinásková, Klára ; Mézl, Martin (referee) ; Jiřík, Radovan (advisor)
This bachelor’s thesis deals with methods of multimodal image registration. The work is focused specifically on the registration of histological sections and MR images, which various studies examine because of improving oncological diagnostics. A substantial part of the work is devoted to theories of registration - types of registration, geometric transformations, criterial functions, interpolation and methods of optimization. There is also an overview of tools, which can be used for multimodal image registration. MR images and histological sections were provided from three different sources. The program for image registration was created in software MATLAB 2020a with a graphical user interface and it includes a converter for editing images before the registration began. In conclusion, the results of registration were analyzed.
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Reduction of metal artifacts in CT data with submicron resolution
Víteček, Jiří ; Mézl, Martin (referee) ; Jakubíček, Roman (advisor)
This diploma thesis deals with reduction of metal artifacts in CT data with submicron resolution. The first part of this thesis briefly describes x-ray computed tomography followed by the description of artifacts of tomographic images and existing approaches of the reduction of metal artifacts. In the second part proposed methods of reduction of metal artifacts and their implementation in Matlab programming environment are described. Finally functionality of algorithms is tested on a newly created database and the results are compared, evaluated and discussed.
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Segmentation of cardiac tissue fibrosis in MRI data
Sokol, Norbert ; Mézl, Martin (referee) ; Kolář, Radim (advisor)
Late gadolinium enhancement cardiovascular magnetic resonance imaging can be used to visualize pre-ablation fibrosis or post-ablation myocardial scar. This can significantly helps physicians with diagnosis patients who suffer from myocardial fibrosis to determine region of fibrosis and for post-operative validation of intervention after radio-frequency catheter ablation. In this thesis, i introduce an algorithm for successful distinguish of fibrosis on datasets of patients with myocardial fibrosis, scanned at Faculty hospital at St. Anne’s University Hospital.
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3D Model of Cardial Tissue Electrical Propagation
Míková, Monika ; Mézl, Martin (referee) ; Hejč, Jakub (advisor)
The aim of this master thesis is to create a simple 3D electro-anatomical model of cardiac tissue that will be able to simulate the electrical activation in both a healthy heart and a heart with arrhytmogenic substrate. The model of electrical activation is realized in the COMSOL Multiphysics, simulation software for modelling using the finite element method. The Fitzhugh-Nagumo equation was used to model the excitatory feature of the myocardium and 2D models of myocardial tissue describing the propagation of action potential in healthy tissue, ischemic tissue, spontaneous action potential formation in the SA node, and spiral wave formation were first developed based on appropriate parameters. Subsequently, simplified 3D models of the heart describing the spread of excitement in a healthy heart, in the presence of accessory pathway and in third-degree atrioventricular block were created. The simplified 3D heart model offers a compromise between computational load and model complexity and can be used as a diagnostic tool for tissue and whole heart adjustment with appropriate equation parameter settings.
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Evolution algorithms for ultrasound perfusion analysis
Hemzalová, Zuzana ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
This thesis deals with the principles of ultrasonic perfusion analysis and methods for determining perfusion parameters. It examines Evolutionary algorithms and their ability to optimize the approximation of dilution curves from ultrasond tissue scannig. It compares the optimization performance of three evolutionary algorithms. Continuous genetic algorithm GA, algorithm SOMA and PSO. Methods are evaluated on simulated and clinical data.
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Identification of the parameters of an electroencephalographic recording system
Svozilová, Veronika ; Sekora, Jiří (referee) ; Mézl, Martin (advisor)
Elektroencefalografický záznamový systém slouží k vyšetření mozkové aktivity. Na základě tohoto vyšetření lze stanovit diagnózu některých nemocí, například epilepsie. Účelem této práce bylo zpracování signálu z toho systému a vytvoření modelového signálu, který bude s reálným signálem porovnán. Uměle vytvořený signál vychází z Jansenova matematického modelu, který byl dále implementován v prostředí MATLAB a rozšířen ze základního modelu na komplexnější zahrnující nelinearity a model rozhraní elektroda – elektrolyt. Dále bylo provedeno měření signálů na EEG fantomu a následná identifikace parametrů naměřených signálu. V první fázi byly testovány jednoduché signály. Identifikace parametrů těchto signálů sloužila k validaci daného EEG fantomu. V druhé fázi bylo přistoupeno k testování EEG signálů navržených podle matematického Jansenova modelu. Analýza veškerých signálů zahrnuje mimo jiné časově frekvenční analýzu či ověření platnosti principu superpozice.
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Presure measurement in infusion system
Fialová, Lenka ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
The first part of this work is about history of infusion technology, specially about recent developments in electronic infusion devices. Then, there are described basic principles of infusion pumps and syringe pumps. The second part introduces safety features of infusion technology. An occlusion alarm is one of them. There is described a method of measurement that verifies the functionality of this alarm in two instruments of different producers with various settings. Data obtained by this method are statistically processed and the results discussed.
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Algorithms for the image reconstruction from projections
Zemek, Marek ; Chmelík, Jiří (referee) ; Mézl, Martin (advisor)
This work focuses on the task of reconstructing an image from its projections, particularly in relation to the CT medical imaging modality, and the evaluation of the quality of this reconstruction using various types of algorithms. First, the theory behind contemporary reconstruction algorithms is discussed. Next, this paper deals with the implementation of several simple methods of image reconstruction in Matlab, their application on simulated as well as real data, and subsequent evaluation in terms of reconstruction quality and computational complexity.
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Sensing eye movement using a device BIOPAC and eyetracker Pupil
Vančurová, Johana ; Mézl, Martin (referee) ; Svozilová, Veronika (advisor)
This bachelor thesis is focused on investigation of visual reaction time of driver using eye movements acquivition. Eye movements were acquired by Biopac device and eyetracker Pupil. The main aim of this work is to compare results of own experiments with points of reference. Theoretical part dealt with anatomy, physiology of eye and describing characteristics of EOG signals. Practical part included experimental measurements to which a group of probands was involved. In the last part of this work the obtained results were compared with the points of reference.
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