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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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Flash OFDM network efficiency
Jireček, Martin ; Mikulka, Jan (referee) ; Hanus, Stanislav (advisor)
The FLASH-OFDM networks (Fast Low-latency Access with Seamless Handoff-Orthogonal Frequency-Division Multiplexing) are insert to network of fourth generations. The system are set to fast data transfer. These networks have lower latency than network of third generations. On average is transmission speed for downlink cca 1,5Mb/s and for uplink cca 300-500kb/s. In connection with progress of high-speed network and systems with finite mobility (Bluetooth, IEEE 802.11), creationed want of new standard, which connect both merits. For WiMAX was defined new basic requirements: • mobility of user, • high-speed data transfer with roaming, • the lest latency of systém using aplications in real time, • high count of at the same time communication users in cell, • chance of better control QoS (Quality of Service).
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Segmetation of tomographic data in 3D Slicer
Korčuška, Robert ; Dvořák, Pavel (referee) ; Mikulka, Jan (advisor)
This thesis contains basic theoretical information about SVM-based image segmentation and data classification. Basic information about 3D Slicer software are presented. Aspects of medical images segmentation are described. Workplan and implemetation of SVM method for MRI segmentation in 3D Slicer sofware as extension module is created. SVM method is compared with simple segmentation algorithms included in 3D Slicer. Quality of segmentation, based on SVM, tested on real subjects is experimentaly demonstrated.
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Implementation of restoring method for reading bar code
Kadlčík, Libor ; Bartušek, Karel (referee) ; Mikulka, Jan (advisor)
Bar code stores information in the form of series of bars and gaps with various widths, and therefore can be considered as an example of bilevel (square) signal. Magnetic bar codes are created by applying slightly ferromagnetic material to a substrate. Sensing is done by reading oscillator, whose frequency is modulated by presence of the mentioned ferromagnetic material. Signal from the oscillator is then subjected to frequency demodulation. Due to temperature drift of the reading oscillator, the demodulated signal is accompanied by DC drift. Method for removal of the drift is introduced. Also, drift-insensitive detection of presence of a bar code is described. Reading bar codes is complicated by convolutional distortion, which is result of spatially dispersed sensitivity of the sensor. Effect of the convolutional distortion is analogous to low-pass filtering, causing edges to be smoothed and overlapped, and making their detection difficult. Characteristics of convolutional distortion can be summarized into point-spread function (PSF). In case of magnetic bar codes, the shape of the PSF can be known in advance, but not its width of DC transfer. Methods for estimation of these parameters are discussed. The signal needs to be reconstructed (into original bilevel form) before decoding can take place. Variational methods provide effective way. Their core idea is to reformulate reconstruction as an optimization problem of functional minimization. The functional can be extended by other functionals (regularizations) in order to considerably improve results of reconstruction. Principle of variational methods will be shown, including examples of use of various regularizations. All algorithm and methods (including frequency demodulation of signal from reading oscillator) are digital. They are implemented as a program for a microcontroller from the PIC32 family, which offers high computing power, so that even blind deconvolution (when the real PSF also needs to be found) can be finished in a few seconds. The microcontroller is part of magnetic bar code reader, whose hardware allows the read information to be transferred to personal computer via the PS/2 interface or USB (by emulating key presses on virtual keyboard), or shown on display.
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Construction of an impedance analyzer
Slinták, Vlastimil ; Smékal, Zdeněk (referee) ; Mikulka, Jan (advisor)
The aim of this master’s thesis is to build stand-alone impedance analyzer for mesasuring antennas’ impedance. The vector network analysis is used as measuring method. Analog (with directional coupler and gain and phase detector) and digital (with 8bit AVR microcontrollers) part of analyzer are described and then build.
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