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Implementation narrowly directed beeper
Hladký, David ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
The present final thesis discusses the transmission of a narrowly directional parametric sound beam through an amplitude-modulated ultrasonic wave, utilizing the effect of auto-demodulation in a nonlinear medium and ensuring the subsequent processing of the input signal for the parametric sound transmitter. Emphasis is placed on the mathematical tools that relate to parametric sound transmission in a nonlinear medium. The basic part of the thesis describes a parametric speaker and the associated amplitude modulation techniques, which constitute a major prerequisite for the processing of the transmitted signal. In the following section, the author then analyzes the computational intensity of these techniques, considering applicable hardware approaches. Finally, the fabrication and practical use of the proposed solution are discussed, including the measurement of typical parameters such as the spatial radiation characteristics, total harmonic distortion, and transmission channel bandwidth.
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Methods of deep learning in image processing tasks
Polášková, Lenka ; Marcoň, Petr (referee) ; Mikulka, Jan (advisor)
The clue of learning to recognize objects using neural network lies in imitation of animal neural network's behavior. In spite the details of how brain works is not known yet, the teams consisting of scientists from various medical or technical professions are trying to search for them. Thanks to giants like Geoffrey Hinton science made a big progress in this domain. The convolutional networks which are based on animal model of optical system can be advantageously used for image segmentation and therefore they ware chosen for segmentation of tumor and edema from images of magnetic resonance. The models of artificial neural networks used in this work had achieved the 41\% of success in edema segmentation and 79\% in segmentation of tumor from brain issue.
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Open-source systems for image processing
Slinták, Vlastimil ; Zukal, Martin (referee) ; Mikulka, Jan (advisor)
The aim of this document is to describe open-source libraries for image processing — ITK, VTK and OpenCV. Their architectures are described and it is shown how to compile and use them in real applications. It also provides basic description of algorithms for image processing. In the second part of this document, we try to use ITK library with data-mining environment RapidMiner.
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Design of magnetic bar-code read head
Kadlčík, Libor ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
Magnetic bar-code is composed from ferromagnetic bars printed on a substrate. The amount of ferromagnetic material is low, therefore reading magnetic barcode requires sensitive methods. Principle of methods of sensing both low-intensity magnetic field (fluxgates) and detecting low concentration of ferromagnetic material (resonant circuit, differential sensor) will be described. There are sensors producing frequency-modulated signal, therefore we focus on frequency demodulators as well. Signal acquired by sensor suffers from convolution distortion, reconstruction methods will be introduced. The assembled device consists of sensing oscillator, frequency demodulator, amplifier and reconstructing circuit. Frequency demodulation is done by phase-locked loop or differential demodulator. Reconstruction is based on detection of inflection points, producing square signal (representing bars of barcode). Design of these blocks is described. The device is able to read magnetic barcodes and reconstruct convolutionary distorted acquired signal. The differential demodulator exhibits low noise and low temperature drift (contrary to phase-locked loop). Signal produced by reading 2 mm wide bars is reconstructed without any problems, bars of width less than 1 mm cause troubles in certain cases (due to high degree of convolution distortion).
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Segmentation Methods in Biomedical Image Processing
Mikulka, Jan ; Přibil, Jiří (referee) ; Dostál, Otto (referee) ; Gescheidtová, Eva (advisor)
The PhD thesis deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It is focused primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR) and microscopic images of tissues. It is easy to describe edges of the sought objects using of segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown in this thesis. Research in the area of image segmentation is focused on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. The results of the thesis are methods proposed for automatic image segmentation and classification.
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WLAN and Bluetooth Systems Coexistence
Mikulka, Jan ; Hanus, Stanislav (advisor)
The dissertation thesis deals with a WLAN and Bluetooth systems coexistence. A Bluetooth standard works in an unlicensed frequency band 2,402 – 2,480 GHz. This frequency band is also used by an IEEE 802.11b/g standard (Wi-Fi) which is the most extended representative of WLAN networks. Because Bluetooth and Wi-Fi systems operate in the same frequency band, a mutual signal degradation may appear, when devices are collocated in the same area. In the first part of the dissertation thesis there is a brief summary of 2,402 - 2,480 GHz frequency band regulations and its usage. There are described physical layers of Bluetooth and IEEE 802.11b/g standards and techniques used for a collision avoidance. The main part of the dissertation thesis deals with a development of a new Matlab Simulink model for investigations of the Bluetooth and Wi-Fi standards coexistence. Physical layer models and results of the coexistence simulations are verified by a measurement in real conditions with a help of a modern vector signal analyzer. The results are presented in a graphical form and a brief summary is attached at the end of each chapter. Corresponding tables of simulated and measured values are available in the enclosed CD.
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Study of substances transport in plants stalks
Doubek, Vladimír ; Kubásek, Radek (referee) ; Mikulka, Jan (advisor)
This thesis deals procedure nuclear magnetic resonance and next three of basic measuring technics NMR. Magnetic resonance exploit, that anyone proton and neutron have dynamics moment. Is based on monitoring response coring situated to magnetic field B0 and on interaction with HF electromagnetical wave. Measuring of response signal differ in feed RF pulse. Method spin echo (SE) is based on two pulses 90° and 180° in contrast by Inverse recovery (IR), where is it conversely.By method Hahn echo (measuring efficient relaxation time T2*) is brought 90° pulse. For all methods is final signal over stopping process captured in receiving inductor.
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Measurement of conifers needles surface by MR tomography
Hladík, Roman ; Kubásek, Radek (referee) ; Mikulka, Jan (advisor)
This bachelor thesis deals with the tomography based on magnetic resonance and evaluation of scanned images of conifers needles. At first, it is described the physical basis and methods of magnetic resonance scanning of objects. Another part is devoted to graphical preprocessing, which consist of noise suppression and image segmentation. After that there are described the design and algorithm for parameter estimation implemented to the application. The first experimental measurements were lightly discussed and evaluated in the last part of the work. In the last part there are discussed results of the experimental measurement. The attached documents contain the source code in Matlab language.
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Measurement of tissue embryos by MR imaging methods
Vrba, Jan ; Mikulka, Jan (referee) ; Bartušek, Karel (advisor)
The aim of this work is to determine the volume of water in tissue cultures of spruce MR imaging methods and changes during growth. Was measured set of samples, where was found contain of cluster in each cuts. It describes spin-echo method, which was used for measurement. In this work is given a description of the acquisition, calculation, evaluation and graphical representation of measured values.
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Estimation of instantanenous frequency
Mik, Šimon ; Mikulka, Jan (referee) ; Kubásek, Radek (advisor)
This bachelor’s thesis describes different instantaneous frequency estimators. Various methods are implement into Matlab software and there are introduced conclusions of testing. Methods are compared in two aspects. The first aspect is accuracy of method which depend on time progress input signal. The second aspect is accuracy of method which depend on ratio frequency of input signal and sampling frequency. Outcomes of tests are compared. The result of this work is evaluate properties each method.
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