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Development of Customized Signal Processing SW for dynamic analysis of engineering systems
Witassek, Tomáš ; Kovář, Jiří (referee) ; Lošák, Petr (advisor)
Aim of this thesis is to create a user interface for signal processing mostly in the area of dynamics. First part of this thesis describes the theory of acceleration and force sensors, A/D conversion and corresponding issues such as sampling, quantization and types of convertors. Following part provides a brief summary of National Instruments products for vibration measurement. Next part of this thesis deals with methods of signal processing such as Fourier transform, frequency response functions and experimental modal analysis. Software described in the last part of this thesis is created in LabVIEW enviroment.
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Synthetic Holography
Tvarog, Drahoslav ; Chmelík, Radim (referee) ; Kotačka, Libor (advisor)
The thesis presents method of a creation of computer-generated holograms. The first part is devoted to an introduction of theoretical principles of a generation of synthetic holograms. The second part of the discourse deals with several practical methods of synthetic holograms creation. We present a computer code computing a discrete Fourier transform of an input image. The output of the code is an image matrix binarized in a specifically given way and printed on a transparent slide. When reconstructing the synthetic hologram we initially illuminate the slide with CGH by a plane wave and a reconstructed pattern is magnified through a camera objective to obtain a pattern observable by naked eyes. Finally, we analyze the quality of reconstructed pictures obtained from the synthetic holograms.
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Fourier methods of eliminating optical artifacts in SOHO EIT images
Satýnek, Daniel ; Kosová, Petra (referee) ; Druckmüllerová, Hana (advisor)
This thesis deals with the application of the two-dimensional discrete Fourier transform for the processing and analysis of image data from a space telescope. A method will be described that is used to eliminate periodic artifacts caused by narrow-band pass filters in images from the SOHO EIT spacecraft. The design of a filter in the frequency domain to suppress periodic noise in the image is discussed. Proposed method calculates the amplitudes of the filtered frequencies based on an approximation of the surrounding amplitudes. The algorithm of the method and how to set its parameters will be described.
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Development of Customized Signal Processing SW for dynamic analysis of engineering systems
Witassek, Tomáš ; Kovář, Jiří (referee) ; Lošák, Petr (advisor)
Aim of this thesis is to create a user interface for signal processing mostly in the area of dynamics. First part of this thesis describes the theory of acceleration and force sensors, A/D conversion and corresponding issues such as sampling, quantization and types of convertors. Following part provides a brief summary of National Instruments products for vibration measurement. Next part of this thesis deals with methods of signal processing such as Fourier transform, frequency response functions and experimental modal analysis. Software described in the last part of this thesis is created in LabVIEW enviroment.
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Detect the Use of Retouch Filters in a Face Image
Kraváček, Adam ; Drahanský, Martin (referee) ; Goldmann, Tomáš (advisor)
These days, altering images via filters is one of the easiest ways of enhancing its properties. Social networks like Instagram or Snapchat, focused primarily on image sharing, offer their users the option to apply filters on their images, which alter their colours to make them look better. If someone was to extract images from these platforms, many of these images would have a filter applied. This thesis explains the principles of these filters and focuses on detection of filters on facial images. Several approaches to detecting filters are being experimented with. Detection by analysis of histograms and detection by convolutional neural network achieve the best results and so are implemented in a program with a simple user interface. They achieved a success rate of 94,44% (histogram) and 99,10% (CNN). This thesis also investigates the impact of filters on facial recognition, where the impact varies depending on the filter used. Some filters have a significant impact on the rate of successful identifications, whereas others have little impact.In general, however, it can be said that the changes introduced by the application of filters are not negligible.
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Invisible Image Watermarking using Frequency Domain Feature Points
Pacura, Dávid
For robust invisible watermarking scheme for images, it is crucial to withstand both malicious and common image manipulations (e.g. JPEG compression, pixel jittering or cropping). In this paper, local image features are used. For this, a Maximally Stable Extremal Regions (MSER) detector, which is fast and invariant to affine transformations, is used. The watermark itself is embedded multiple times in circular areas across image. This is achieved by manipulation of magnitude coefficients in frequency domain. During detection, watermark is recovered using majority criterion.
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Radar Signal Processing for Radio Altimeter
Krasňanský, Milan ; Maršík, Lukáš (referee) ; Zemčík, Pavel (advisor)
Táto diplomová práca sa zaoberá návrhom a implementáciou algoritmu pre spracovaniu signálu z radaru využívajúceho frekvenčne modulovanú kontinuálnu vlnu. Cieľom je implementácia algoritmu, ktorý by bol dostatočne rýchly (výpočet v reálnom čase na cieľovej platforme) a dostatočne presný pre použitie v rádiovýškomere v ľahkom lietadle so zameraním na použitie počas pristávacieho manévru. Hlavnou metódou spracovania signálu, použitou v implementácii, je Diskrétna Fourierova transformácia. Vytvorený algoritmus bol otestovaný na reálnych letových dátach a pre pristávací manéver dosiahol uspokojivé výsledky.
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Radar Signal Processor in FPGA
Přívara, Jan ; Musil, Petr (referee) ; Maršík, Lukáš (advisor)
This work describes design and implementation of radar processor in FPGA. The theoretical part is focused on Doppler radar, principles of radar signal processing methods and target platform Xilinx Zynq. The next part describes design of radar processor including its individual components and the solution is implemented. FPGA components are written in VHDL language. In the end, the implementation is evaluated and possible continuation of this work is stated.
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Links Between Differential and Linear Cryptanalysis
Töpfer, Jakub ; Hojsík, Michal (advisor) ; Göloglu, Faruk (referee)
This thesis concerns the relations between correlation matrix, difference propagation matrix and other matrices used in the block cipher cryptanalysis. We show that some relations between these matrices can be seen just as a change of basis provided by the discrete Fourier transform. This can be used for an easier proof of a well-known theorem. We also study properties of difference propagation matrix, describe a class of vectorial Boolean functions which have the same difference propagation matrix and state a numerically justified hypothesis that this class contains all such functions.
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High-Level Synthesis of Digital Circuits
Jendrušák, Ján ; Fujcik, Lukáš (referee) ; Dvořák, Vojtěch (advisor)
This thesis deals with practical test of high-level synthesis as a digital circuits design method and its current progress in creating RTL models. At first main tasks of HLS will be described together with C++ library of classes called SystemC, which implements hardware constructs, notion of time and hardware datatypes with arbitrary bit width. After that thesis focuses on discrete Fourier transform and its fast form of computation – fast Fourier transform. In the practical part of thesis reference FFT model is written in C++ language, which is later edited appropriately a synthesized with Stratus High-Level Synthesis tool into several hardware architectures.
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