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Removal of a Known Signal from a Recording
Hošek, Pavel ; Žmolíková, Kateřina (referee) ; Černocký, Jan (advisor)
The goal of this bachelor thesis is to design and implement method for removing known signal from recorded sound. The introductory part of the thesis summarizes the theory of sound properties, basics of signal processing, and system identification. Subsequently, the data are presented and the way of testing is stated. Afterwards, the development of a method for removing a known signal from a recording is described. Finally, experiments are performed, which include a comparison of selected methods. The best methods achieved relatively good results and they were mostly able to remove the known signal sufficiently.
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Signal Decomposition using EMD transform
Mžourek, Zdeněk ; Mekyska, Jiří (referee) ; Smékal, Zdeněk (advisor)
Aim of this thesis is to introduce empiric mode decomposition as a method for decomposing arbitrarily nonlinear and non-stationary signal into intrinsic mode functions. Using empiric modal decomposition together with Hilbert transform produces instantaneous frequency. We can use this instatenous frequency to create a Hilbert spectrum and use it for analysis in time-frequency domain. In next part we show several drawbacks of this method. We also present several ways how to improve empirical mode decomposition algorithm to obtain better results. An example of decomposition by empiric mode decompositon is made to illustrate how the whole procedure works.
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Selected Aspects of Statistical Significance Testing in Time-Frequency Analysis
Klejmová, Eva ; Kohl,, Zdeněk (referee) ; Fidrmuc, Jarko (referee) ; Poměnková, Jitka (advisor)
Přeložená dizertační práce se zabývá analýzou a posouzením kvality odhadu frekvenční a časově-frekvenční transformace dat a formulaci doporučení pro práci s metodami. Při použití těchto metod vyvstává otázka, jak vyhodnotit, které složky spektrogramu jsou statisticky významné a které nikoli. V této práci analyzujeme vlastnosti standardních testů statistické významnosti. Diskutujeme o jejich výhodách a nevýhodách s ohledem na heteroskedastický charakter dat. Na základě našich experimentů jsou v práci navrženy dva typy testovacích metod, které snižují negativní aspekty standardních testů. Práce jen zakončena vytvořením rámce pro filtrování dat pomocí námi navržených metod.
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Time-frequency analysis of Czech republic gross domestic product
Tráge, David ; Poměnková, Jitka (referee) ; Maršálek, Roman (advisor)
The aim of this master's thesis is to get familier with problematic and concepts of econometrics (GDP, investment, usage and others). We see into used data mainly their characters and expectations and we discuss possibilities of frequention and time-frequention analysis of these data by Fourier and Wavelet transform. Data of quarter development of gross domestic product in Czech Republic, EU and USA will be analysed by the help of programm MATLAB. Data will be filtered by three ekonomic filters: Hodrick-Prescott, Baxter-King and Christiano-Fitzgerald filters. The aim is to find cyclic elements in developments of GDPs and to suggest an optimal type of analysis.
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Non-contact detection of physiological parameters from image sequences
Bršlicová, Tereza ; Janoušek, Oto (referee) ; Kolář, Radim (advisor)
This thesis deals with the study of contactless and non-invasive methods for estimating heart and respiratory rate. Non-contact measurement involves sensing persons by using camera and the values of the physiological parameters are then assessed from the sets of image sequences by using suitable approaches. The theoretical part is devoted to description of the various methods and their implementation. The practical part describes the design and realization of the experiment for contactless detection of heart and respiratory rate. The experiment was carried out on 10 volunteers with a known heart and respiratory rate, which was covered by using of a sophisticated system BIOPAC. Processing and analysis of the measured data was conducted in software environment Matlab. Finally, results from contactless detection were compared with the reference from measurement system BIOPAC. Experiment results are statistically evaluated and discussed.
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Selected Aspects of Statistical Significance Testing in Time-Frequency Analysis
Klejmová, Eva ; Kohl,, Zdeněk (referee) ; Fidrmuc, Jarko (referee) ; Poměnková, Jitka (advisor)
Přeložená dizertační práce se zabývá analýzou a posouzením kvality odhadu frekvenční a časově-frekvenční transformace dat a formulaci doporučení pro práci s metodami. Při použití těchto metod vyvstává otázka, jak vyhodnotit, které složky spektrogramu jsou statisticky významné a které nikoli. V této práci analyzujeme vlastnosti standardních testů statistické významnosti. Diskutujeme o jejich výhodách a nevýhodách s ohledem na heteroskedastický charakter dat. Na základě našich experimentů jsou v práci navrženy dva typy testovacích metod, které snižují negativní aspekty standardních testů. Práce jen zakončena vytvořením rámce pro filtrování dat pomocí námi navržených metod.
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Classification Of Heart Sounds Using Time-Frequency Analysis And Image Processing Methods
Demjan, Michal ; Nejedlý, Petr
This paper describes the algorithm for detection of heart sounds from phonocardiogram record (PCG) using time-frequency analysis and image processing technique. Presented algorithm extracts time-frequency features using continuous wavelet transform (CWT) and subsequently applies image processing methods such as morphological operations and connected components labeling on hearth sounds segment S1-S2. Furthermore, the segmented PCG signal undergoes correction procedure, which uses the Smith-Waterman local alignment algorithm to correctly predict heart sound sequence.
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Removal of a Known Signal from a Recording
Hošek, Pavel ; Žmolíková, Kateřina (referee) ; Černocký, Jan (advisor)
The goal of this bachelor thesis is to design and implement method for removing known signal from recorded sound. The introductory part of the thesis summarizes the theory of sound properties, basics of signal processing, and system identification. Subsequently, the data are presented and the way of testing is stated. Afterwards, the development of a method for removing a known signal from a recording is described. Finally, experiments are performed, which include a comparison of selected methods. The best methods achieved relatively good results and they were mostly able to remove the known signal sufficiently.
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A Method to Supress Interferences in Wigner-Ville Distribution
Pikula, Stanislav ; Pazdera, Luboš (referee) ; Hájek, Karel (referee) ; Beneš, Petr (advisor)
The doctoral thesis focuses on signal representation in the time-frequency domain with constant resolution. In theoretical introduction the possibilities of displaying a signal in time and frequency are summarized. Attention is concentrated on comparison of short-time Fourier Transform (STFT) and Wigner-Ville Distribution (WVD). The latter achieves a significantly better resolution, especially for a linearly modulated signal. The disadvantage of WVD, which is the presence of interferences resulting from the calculation of the instantaneous autocorrelation function, is described in detail. These interferences are due to the presence of multiple components in the signal or its non-linear modulation. Subsequently, several methods are discussed, which can suppress these interferences, but at the cost of resolution loss. One of the interference suppression methods is smoothed pseudo Wigner-Ville distribution. It is further used in this thesis for the analysis of interference suppression when various filtrations in the time-frequency plane are applied. Several signals with multiple components or various non-linear modulations are used. Based on the analysis, a method using a set of variously smoothed pseudo Wigner-Ville distributions is designed to estimate the time-frequency representation with high resolution and minimal interferences. To compare the results to other methods, the quantitative metrics used in the literature are compared. To select the appropriate one a new metric is suggested. It is applicable to simulated signals and uses mean square error. Based on the comparison, the Stankovi\'{c} measure is selected as the most appropriate for comparing results. The selected metric is used to determine the appropriate minimal number of differently smoothed pseudo Wigner-Ville distributions. Using the selected metric, the proposed method is compared with other methods. These are STFT with optimized window length, S-method with optimized parameter and optimization method using radial Gaussian kernel (RGK). These methods are compared based on the set of signals previously used for interference suppression analysis. In addition, noises are added to the signals. Finally, the methods are also compared based on the real bat echo signal. In conclusion, the proposed method outperforms the compared methods in suppressing interference and resolution.
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