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Special Surfaces
Ochodnický, Erik ; Vašík, Petr (referee) ; Doupovec, Miroslav (advisor)
The aim of this thesis is to create an overview of special surfaces and to define their characteristics. Categories of surfaces that I found the most important are surfaces of revolution, minimal, with constant Gaussian curvature, and finally Clairaut surfaces. For every category I'll introduce, in my opinion, the most important examples of surfaces along with their parametrizations and I'll describe them. Surfaces will be accompanied by images, created in MATLAB. In the last part I'm going to focus on Clairot patches, on finding geodesics on these surfaces and their description. I'll show numerous original images of geodesics on diverse surfaces.
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Modelling of perfusion curves in dynamic magnetic resonance
Ochodnický, Erik ; Mangová, Marie (referee) ; Rajmic, Pavel (advisor)
Perfusion MRI can provide information about perfusion characteristics of the observed tissue, which makes it a widely applicable medical procedure. Measuring process of MRI is very time-consuming, and therefore, using classical reconstruction methods, we are often not able to obtain enough samples to accomplish the needed time and space resolution for perfusion analysis. That is why it is necessary to use compressed sensing, which allows reconstruction from under-sampled data by solving an optimization model. In this work, several models for reconstruction of an image sequence are verified on real and artificial data, along with multiple algorithms capable of solving these models. Among the optimization models used in this work are two L+S models with different regularization of the S component that are solved by Forward-Backward and Chambolle-Pock algorithm. The quality of reconstruction for various models was compared especially by their perfusion curves. In the last section, we explore possible modifications of the SASS model in order to increase quality of reconstruction and resistance to under sampling for the purpose of better adaptation for dynamic data.
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Modelling of perfusion curves in dynamic magnetic resonance
Ochodnický, Erik ; Mangová, Marie (referee) ; Rajmic, Pavel (advisor)
Perfusion MRI can provide information about perfusion characteristics of the observed tissue, which makes it a widely applicable medical procedure. Measuring process of MRI is very time-consuming, and therefore, using classical reconstruction methods, we are often not able to obtain enough samples to accomplish the needed time and space resolution for perfusion analysis. That is why it is necessary to use compressed sensing, which allows reconstruction from under-sampled data by solving an optimization model. In this work, several models for reconstruction of an image sequence are verified on real and artificial data, along with multiple algorithms capable of solving these models. Among the optimization models used in this work are two L+S models with different regularization of the S component that are solved by Forward-Backward and Chambolle-Pock algorithm. The quality of reconstruction for various models was compared especially by their perfusion curves. In the last section, we explore possible modifications of the SASS model in order to increase quality of reconstruction and resistance to under sampling for the purpose of better adaptation for dynamic data.
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|
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Special Surfaces
Ochodnický, Erik ; Vašík, Petr (referee) ; Doupovec, Miroslav (advisor)
The aim of this thesis is to create an overview of special surfaces and to define their characteristics. Categories of surfaces that I found the most important are surfaces of revolution, minimal, with constant Gaussian curvature, and finally Clairaut surfaces. For every category I'll introduce, in my opinion, the most important examples of surfaces along with their parametrizations and I'll describe them. Surfaces will be accompanied by images, created in MATLAB. In the last part I'm going to focus on Clairot patches, on finding geodesics on these surfaces and their description. I'll show numerous original images of geodesics on diverse surfaces.
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