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Measurement of small objects by magnetic resonance
Chotaš, Kryštof ; Bartušek, Karel (referee) ; Klusáček, Stanislav (advisor)
Bachelor thesis deals with the issue of noise reduction in magnetic resonance imaging. In this thesis we discuss about suitable methods of noise reduction for images obtained by magnetic resonance tomography. Including classical methods we also discuss noise suppression by getting fewer slices than in ordinary situation. Then we would obtain remaining slices by interpolation. This thesis also include comparison of application of these methods. This thesis also deals with the issue of magnetic resonance, which is described in first chapter.
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Averaging of biological signals
Němeček, Tomáš ; Vítek, Martin (referee) ; Smital, Lukáš (advisor)
The main objectives of this thesis are to study theory of signal averaging, filtered residue method and methods of stretching/shrinking signal. It will also test the functionality of those methods. Thesis contains theoretical analysis, explanation of principles and testing of behaving of used methods.
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Detection of the RF Signal on MRI
Břínek, Adam ; Kolář, Radim (referee) ; Drastich, Aleš (advisor)
Presented bachelor’s thesis is focused on the detection of MR signal. The aim is to propose the laboratory exercise. The difference between the linear and quadrature detections is described with emphasis on SNR. The program was created in Matlab GUI to be provided in the laboratory excercise. The program is presented in the text.
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Internet Connection variants using present TV cable wiring
Lukáč, Michal ; Martinásek, Zdeněk (referee) ; Stančík, Peter (advisor)
This dissertation examines data transfers along the existing lines of cable TV. PLC equipment has been selected as the focus of this examination. The essay examines the question of Multicarrier modulation and focuses more specifically onto the problem of OFDM modulation, which is being used by the selected equipment. It further describes the process of integration of PLC equipment into the cable TV network, modifications of the CATV and the basic topology of the created data networks. The essay also offers a closer look onto a PLC modem and Head End from Corinex that have been used in the implementation of a data network in a selected rural settlement. The author has also raised the issue of the problems connected with cable wires connected with this particular type of data transfers and the solutions of some of the encountered problems. The characteristics of this network have then been measured during normal operation of the created network. Measurements have been carried out in order to determine the transfer speed on a physical and transfer level, the SNR of specific connections and the signal attenuation. The measurements have confirmed the suitability of the used PLC equipment for the purposes of data transfer along the cable TV lines as far as data speed and signal strength was concerned. A map of the particular cable TV lines and the PLC equipment has been included in the attachment.
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Characterization of scanning transmission electron microscopy images of thin biological sections
Novotná, Veronika ; Nebesářová,, Jana (referee) ; Krzyžánek, Vladislav (advisor)
Diplomová práce popisuje fyzikální principy mikroskopů TEM, SEM a STEM spolu s jejich vhodností pro pozorování vzorků citlivých na elektrony, jako jsou zalévací média či biologické vzorky. Dále je popsána příprava vzorků pro STEM (TEM) a popis interakcí, ke kterým dochází mezi primárním elektronovým svazkem a vzorkem. Součástí práce je také pojednání o zpracování mikroskopických obrazů s podkapitolou o metodách kvantitativního porovnání obrazů ze STEM. Praktická část práce je zaměřena zejména na měření úbytku hmoty zalévacích médií (Epon, Spurr, LR White) způsobený primárním svazkem elektronů v nízkonapěťovém STEM. Ultratenké řezy několika tlouštěk byly zkoumány při různých nastaveních mikroskopu (urychlovací napětí, celková dávka, proud svazku, čištění povrchu vzorku a komory mikroskopu) a zobrazovacích módech (světlé a tmavé pole). Dále jsou zkoumány také biologické vzorky Krásnoočka štíhlého (Euglena gracilis) zalitého v pryskyřicích Epon a Spurr. Nasbírané snímky, vytvořené algoritmy a získané výsledky jsou diskutovány a zhodnoceny.
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Hierarchical Coding of Moving Pictures
Špaček, Milan ; Rášo, Ondřej (referee) ; Schimmel, Jiří (advisor)
Bachelor‘s thesis deals with hierarchical coding – scaling – of moving pictures in currently widely used compression algorithms MPEG-2 and MPEG-4. Scaling is the process whereby the encoded data stream is divided into graduated layers, adapted especially to the possibilities of transmission media and capabilities of terminal devices. The content of the base layer is a signal with reduced quality. The content of one or more extension layers is a supplementary picture information, completing the signal to a full quality form. The decoder, depending on its abilities and external circumstances, can decode only the relevant layers from the received bitstream. The thesis focuses in the theoretical part on the detailed description of encoding and decoding video signal according to MPEG standards using three types of scalability. In the concrete, the spatial, qualitative SNR and Fine granular scalability are mentioned. In the practical part of thesis was created an educational application in Matlab environment with its own graphical user interface, which implements the functions performing spatial, qualitative SNR and Fine granular scalability. Based on the user-specified input parameters, it performs scaling the image and then displays the outputs of individual layers after scaling and after the image reconstruction. The input of the programme, in which a hierarchical coding is done, is the image in bitmap format with any size in RGB format.
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Subjective and Objective Assessment of Speech Quality
Bezdíček, Martin ; Balík, Miroslav (referee) ; Vondra, Martin (advisor)
This Bachelor's thesis is focused on subjective and objective methods for evaluation of speech quality. In the first part, the quality of transmitted speech signal and its distorting effects are given. Futher, subjective and objective methods for evaluation of speech are described. The objective methods: Signal to Noise Ratio (SNR), Segmental Signal to Noise Ratio (SSNR), the methods for evaluation in spectral area (Log Likelihood Ratio Measures and Cepstral Distance) and also Perceptual Evaluation of Speech Quality (PESQ). The next part deals with the correlation analysis which is used for the comparison of subjective and objective methods. In the last part of the bachelor thesis the results of subjective and objective methods are presented. Finally on the basis of correlation analysis with the results of subjective method, the best objective method is recommended.
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Comparison of heart activity sensing devices
Babicová, Martina ; Smital, Lukáš (referee) ; Smíšek, Radovan (advisor)
The goal of this work is comparison of heart activity sensing devices. However, an ECG record cannot be evaluated with the presence of muscle interference. Removing this noise is one of the needs for device success. The theoretical part represents electrophysiology of the heart, electrocardiography, various interferences types, theoretical basis for recording of biosignals including used devices and methods signal quality estimation. The practical part is SNR (signal-to-noise ratio) calculation. The Wavelet filter and Wiener filter-based wavelet domain are used to separate the useful and noise component.
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Measurement and analysis of the DAB system
Kaštánek, Petr ; Kufa, Jan (referee) ; Polák, Ladislav (advisor)
This thesis deals with the measurement and analysis the performance of the Digital Audio Broadcasting (DAB) system. Theoretical part of the work contains a brief description of the signal processing chain of DAB. Attention is devoted to physical layer (PHY). In the experimental part of the work is designed and implemented laboratory measuring workplace for reception, processing and evaluation of DAB signal. The RTL2832U software defined radio (SDR) is used as a receiver of the DAB signal. The functionality of the proposed concept is verified by a detailed measurement.
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