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Solid Foams Based on Acetalized PVAl
Mach, Václav ; Klučáková, Martina (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with the preparation of solid hydrophilic sponges made of acetalized PVAl. The sponges were produced by foaming by gaseous reaction by-product. The experimental work also includes the study of active compound immobilization into the sponge (finely ground lignite as a heavy metal sorbent).
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Acoustical measurent in real environment
Mach, Václav ; Mačák, Jaromír (referee) ; Míča, Ivan (advisor)
This bachelor thesis discusses the issue of acoustical measurement. There are dierent signals described, which are used for this purposes, both MLS and esweep, compared their advantages and disadvantages and made some practical demonstrations of impulse response measurement. Furthermore, the fundamentals of reberbation time measurement are described in theory. The practical part of this thesis consists of the measurement application, written in the C++ language and mainly targeted for Linux systems. Qt multiplatform toolkit has been utilized for the GUI part.
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Implementation of voice activity detectors using open-source libraries in C language
Mach, Václav ; Špiřík, Jan (referee) ; Míča, Ivan (advisor)
This diploma thesis discusses the issue of Voice Activity Detection. There are two types of detectors described: energetic and statistics. Their funktionality is proved in the Matlab environment. Further, the implemetation of VADs is made through C language with standard libraries and GSL open-source libraries. The realized algorithms are compared in the scope of processing time of computation, memory management and a single mathematical operations stress. Also a comparism of the processing time according to segment length was made.
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Algorithms in colour management
Stecík, Július ; Mach, Václav (referee) ; Rajmic, Pavel (advisor)
Thesis briefly discusses the issues of color perception and effects associated with it. Further describes color model and its mathematical definition, which are used by color management. Briefly analyzes important elements of ICC profile. In second part two java applications were designed and programmed. First one evaluates visible spectrum and graphically demonstrate procedure for obtaining trichromacy information from this spectrum. Second application analyzes ICC profile and derives gamut of described device.
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Advanced Methods of Audio Signals Interpolation
Pospíšil, Jiří ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This diploma thesis deals with the theoretical analysis of the predictive methods of signal interpolation and signal modeling using sinusoidal model. On the basis of this theory the algorithm for the reconstruction of the missing sections in the audio signal is implemented in computing environment MATLAB. Results of mass testing reconstructions are displayed using objective methods SNR and PEMO-Q. Further experiments are carried out on single signals and their evaluation is described.
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Dictionary learning for sparse signal reconstruction
Ozdobinski, Roman ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This bachelor thesis discusses the dictionary learning for the reconstruction of signal based on sparse representations. There are methods of static and optimized dictionary of matrices described that are used with approximative Orthogonal Matching Pursuit algorithm to reconstruct the missing groups of samples in the audio signal. There is theoretically analyzed algorithm for learning K-SVD dictionary together with its implementation in Matlab. Furthermore, the selected dictionaries are compared to the various types of audio signals.
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Speech activity detector in digital signal processor
Kovařík, Jiří ; Mach, Václav (referee) ; Sysel, Petr (advisor)
In this diploma thesis were created voice activity detectors according to the standard ITU-T G.729 and G.723.1. The voice activity detectors were implements in the digital signal processor TMS320C6416 made by Texas Instruments. At the same time detectors were designed using by MATLAB programming language. The diploma thesis can be divided into two parts. In the theoretical section provides information on how to report detectors in the standard ITU-T G.729 and G.723.1. In the implementation part is described steps in the implementation of the detector in signal processor TMS320C6416 and there are discussed various differences compared to the documentation.
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Methods of acquisition and processing of images based on sparse representations
Talár, Ondřej ; Mach, Václav (referee) ; Rajmic, Pavel (advisor)
Thesis deals with the reconstruction possibilities provided by the sparse representation of signals. This representation reduces the signal to a mere vector of elements which indicate the signal portion in the dictionary array. It outlined the problems with the quantized signal and recalled modulation type, involving a quantization and its ways. The solution is selected Douglas-Rachford algorithm that allows us to approximate on to the set of all acceptable solutions. At the end is demonstrated problem solution and several tests for presentation of created program.
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Applications of Dictionary Learning Methods for Audio Inpainting
Ozdobinski, Roman ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This diploma thesis discusses methods of dictionary learning to inpaint missing sections in the audio signal. There was theoretically analyzed and practically used algorithms K-SVD and INK-SVD for dictionary learning. These dictionaries have been applied to the reconstruction of audio signals using OMP (Orthogonal Matching Pursuit). Furthermore, there was proposed an algorithm for selecting the stationary segments and their subsequent use as training data for K-SVD and INK-SVD. In the practical part of thesis have been observed efficiency with training set selection from whole signal compared with algorithm for stationary segmentation used. The influence of mutual coherence on the quality of reconstruction with incoherent dictionary was also studied. With created scripts for multiple testing in Matlab, there was performed comparison of these methods on genre distinct songs.
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Inpainting of Missing Audio Signal Samples
Mach, Václav ; Polec,, Jaroslav (referee) ; Koldovský,, Zdeněk (referee) ; Rajmic, Pavel (advisor)
V oblasti zpracování signálů se v současné době čím dál více využívají tzv. řídké reprezentace signálů, tzn. že daný signál je možné vyjádřit přesně či velmi dobře aproximovat lineární kombinací velmi malého počtu vektorů ze zvoleného reprezentačního systému. Tato práce se zabývá využitím řídkých reprezentací pro rekonstrukci poškozených zvukových záznamů, ať už historických nebo nově vzniklých. Především historické zvukové nahrávky trpí zarušením jako praskání nebo šum. Krátkodobé poškození zvukových nahrávek bylo doposud řešeno interpolačními technikami, zejména pomocí autoregresního modelování. V nedávné době byl představen algoritmus s názvem Audio Inpainting, který řeší doplňování chybějících vzorků ve zvukovém signálu pomocí řídkých reprezentací. Zmíněný algoritmus využívá tzv. hladové algoritmy pro řešení optimalizačních úloh. Cílem této práce je porovnání dosavadních interpolačních metod s technikou Audio Inpaintingu. Navíc, k řešení optimalizačních úloh jsou využívány algoritmy založené na l1-relaxaci, a to jak ve formě analyzujícího, tak i syntetizujícího modelu. Především se jedná o proximální algoritmy. Tyto algoritmy pracují jak s jednotlivými koeficienty samostatně, tak s koeficienty v závislosti na jejich okolí, tzv. strukturovaná řídkost. Strukturovaná řídkost je dále využita taky pro odšumování zvukových nahrávek. Jednotlivé algoritmy jsou v praktické části zhodnoceny z hlediska nastavení parametrů pro optimální poměr rekonstrukce vs. výpočetní čas. Všechny algoritmy popsané v práci jsou na praktických příkladech porovnány pomocí objektivních metod odstupu signálu od šumu (SNR) a PEMO-Q. Na závěr je úspěšnost rekonstrukce poškozených zvukových signálů vyhodnocena.
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