|
|
Audio codecs and their perceptual quality evaluation
Hudec, Andrej ; Schimmel, Jiří (referee) ; Rajmic, Pavel (advisor)
The bachelor thesis deals with audio codecs and tests to evaluate their listening quality. The thesis offers a description of the properties of human hearing, a brief introduction to the issues of audio coding, types of audio data compression and listening tests. The bachelor thesis also contains a theoretical description of the coding processes of selected audio codecs, evaluation of measuring their computational complexity and evaluation of listening quality of each of them using listening tests. HTML, CSS, Javascript and Python programming languages were used to implement the listening test environment. The audio files examined in the listening tests were obtained using the FFmpeg library.
|
|
|
Creating programs for teaching signal and image processing
Novotný, Luděk ; Číž, Radim (referee) ; Rajmic, Pavel (advisor)
The bachelor thesis deals with the problém of creating interactive JAVA applets. The practical part of work consist of desing, development and debugging four applets. The first one clearly explains the issue of phasor theory, the second one shows frequency filtering of audio signals, the third one demonstrates artificial coloring of grayscale images and the fourth one creates Huffman code from input text. The theoretical part describes the JAVA language, advantages of applets and theory, which relates to particular applets.
|
|
|
Increasing Resolution in Perfusion Magnetic Resonance Imaging Using Compressed Sensing
Mangová, Marie ; Polec,, Jaroslav (referee) ; Šmídl, Václav (referee) ; Rajmic, Pavel (advisor)
Perfusion magnetic resonance imaging is a medical diagnostic method which requires high spatial and temporal resolution simultaneously to capture dynamics of an intravenous contrast agent which is used to perfusion measurement. However, magnetic resonance imaging has physical limits which do not allow to have this resolution simultaneously. This thesis deals with compressed sensing which enables to reconstruct measured data from relatively few acquired samples (below Nyquist rate) while resolution required to perfusion analysis is increased. This aim could be achieved with suitably proposed apriory information about sensed data and model proposal. The reconstruction is then done as an optimization problem. Doctoral thesis brings several new reconstruction models, further proposes method to debias this estimates and examines influence of compressed sensing onto perfusion parameters. Whole thesis is ended with extension of compressed sensing into three-dimensional data. Here, the influence of reconstruction onto perfusion parameters is also described. In summary, the thesis shows that due to compressed sensing, temporal resolution can be increased with the fixed spatial resolution or spatial resolution can be increased with the fixed temporal resolution.
|
|
|
Making OpenType fonts with free software
Bednár, Peter ; Mekyska, Jiří (referee) ; Rajmic, Pavel (advisor)
In thesis themes of typography and computer font of OpenType format is described in details. At the beginning attention is paid to historical development of typeface, where stress is laid mainly on development of Roman and white letter with their characteristics. Having presented basis of typography work is concentrated on topic of digital font with emphasis on possibilities of OpenType format. Further its characteristics and advantages were listed compared to another formats and it was evaluated as format appropriate also for creating font in education process. Letterspacing and kerning were mentioned between basic graphical modifications in creating fonts. In theoretical part of the thesis they were examined in available programs designed for creating font in OpenType format. Except free available means into summary were included also commercial types due to absence of more advanced instruments and functions with free available applications. In evaluation was found that the most convenient for education is Fontlab Fontographer commercial program, free Type lite and Fontforge indicated for Open-source platform. Practical part of the thesis is focused on two chosen programs for creating main font characteristics. The goal was to detect if it is possible to reach identical results when using both programs. Fontographer program enabled to use wide tool palette dedicated to vector graphic processing by means of Adobe Illustrator similar instrument. In the case of Type lite program there were rather less instruments, what is sufficient for elementary work and familiarization with creating of digital typeface. Freeware shortage is basic absence of kerning, spacing or hinting functions. Comparing program possibilities, it falls that freeware programs based on OS Windows with their functionality are sufficient only for entry level users. The best option within free available programs is Fontforge for OS Linux which supports mentioned typographic functions. Fontographer was recommended for teaching of basic characteristics of OpenType font format. Another goal of the thesis was creating of recommended work procedure for creating basic characteristics of OpenType font for students, that is enclosed at the end of the thesis.
|
|
|
New methods for super-resolution imaging
Kučera, Ondřej ; Rajmic, Pavel (referee) ; Špiřík, Jan (advisor)
This master's thesis deals with methods of increasing the image resolution. It contens as a description of theoretical principles and description of calculations which are wellknown nowdays and are usually used for increasing image resolution both description of new methods which are used in this area of image procesing. It also contens a method which I suggested myself. There is also a description of methods for an evaluation of image similarity and a comparation of results from methods which are described in this thesis. This thesis includes implementations of selected methods in programming language MATLAB. It was created an application, which realizes some methods of increasing image and evaluate their results relation to the original image using PSNR and SSIM index.
|
|
|
Overcomplete Mathematical Models with Applications
Tonner, Jaromír ; Witkovský,, Viktor (referee) ; Martišek, Dalibor (referee) ; Rajmic, Pavel (referee) ; Veselý, Vítězslav (advisor)
Chen, Donoho a Saunders (1998) studují problematiku hledání řídké reprezentace vektorů (signálů) s použitím speciálních přeurčených systémů vektorů vyplňujících prostor signálu. Takovéto systémy (někdy jsou také nazývány frejmy) jsou typicky vytvořeny buď rozšířením existující báze, nebo sloučením různých bazí. Narozdíl od vektorů, které tvoří konečně rozměrné prostory, může být problém formulován i obecněji v rámci nekonečně rozměrných separabilních Hilbertových prostorů (Veselý, 2002b; Christensen, 2003). Tento funkcionální přístup nám umožňuje nacházet v těchto prostorech přesnější reprezentace objektů, které, na rozdíl od vektorů, nejsou diskrétní. V této disertační práci se zabývám hledáním řídkých representací v přeurčených modelech časových řad náhodných veličin s konečnými druhými momenty. Numerická studie zachycuje výhody a omezení tohoto přístupu aplikovaného na zobecněné lineární modely a na vícerozměrné ARMA modely. Analýzou mnoha numerických simulací i modelů reálných procesů můžeme říci, že tyto metody spolehlivě identifikují parametry blízké nule, a tak nám umožňují redukovat původně špatně podmíněný přeparametrizovaný model. Tímto významně redukují počet odhadovaných parametrů. V konečném důsledku se tak nemusíme starat o řády modelů, jejichž zjišťování je většinou předběžným krokem standardních technik. Pro kratší časové řady (100 a méně vzorků) řídké odhady dávají lepší predikce v porovnání s těmi, které jsou založené na standardních metodách (např. maximální věrohodnosti v MATLABu - MATLAB System Identification Toolbox (IDENT)). Pro delší časové řady (500 a více) obě techniky dávají v podstatě stejně přesné predikce. Na druhou stranu řešení těchto problémů je náročnější, a to i časově, nicméně výpočetní doba je stále přijatelná.
|
|
|
Graph theory - implementation of selected problems
Stráník, František ; Rajmic, Pavel (referee) ; Koutný, Martin (advisor)
This work is intended on identification with basic problems from the graphs theory area. There are the basic conceptions as well more complicated problems described. The one part of this work is specialized in working of individual types of graphs. It starts with single linked list through double linked list after as much as trees which represented the simplest graphs textures. The other part of this work devotes to the whole graph and describes more complicated problems and their resolution from the theory graphs area. Among these problems belongs to searching in graphs help by Depth First Search and Breadth First Search methods. Then searching the shortest way help by the specific algorithms as are: Dijkstra´s algorithm, Floyd-Warshall´s algorithm and Bellman-Ford´s algorithm. The last part is devoted to problems with searching minimal frames of graphs with usage Kruskal´s algorithm, Jarnik´s algorithm and Boruvka´s algorithm methods.
|
|
| |
|
|
Separation of dynamic and static structures in a videosequence
Serediuk, Vadym ; Pavlík, Jan (referee) ; Rajmic, Pavel (advisor)
The aim of this bachelor thesis is the description and implementation of methods for the separation of low-rank and sparse structures in image sequence, mainly focusing on methods based on convex optimization. The beginning of the work is devoted to the description of basic mathematical concepts and definitions used in the work. The next comes the description of general case of background-foreground separation in video, followed by a brief overview of existing approaches based on various mathematical models. Then, methods based on matrix decomposition are described in more detail, a convex minimization task for background separation is defined. This is followed by a practical part, where the used methods are first described and then implemented in MATLAB scripts. At the end, the analysis and comparison of the results (obtained both using own scripts and external library) is performed.
|
|
|
Algorithms for segmented wavelet image transform
Kořínek, Petr ; Průša, Zdeněk (referee) ; Rajmic, Pavel (advisor)
The thesis deals with wavelet signal transform with the intention of image signal. First part of this work contains the basic methods for signal processing. Fourier transformation and principles of wavelet signal transform is discussed, the fundamentals of segmented discrete-time wavelet transform (SegDTWT) and the segmented discrete-time wavelet 2D signal transform (SegDTWT2D) derivation are described as well. Main purpose of this thesis is in the segmented discrete-time wavelet 2D signal transform (SegDTWT2D) concept and its implementation which can work with two dimension signal.
|
guest ::
