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Modern coding of speech signals using overcomplete models
Zapletal, Ondřej ; Průša, Zdeněk (referee) ; Rajmic, Pavel (advisor)
The theoretical contents of this thesis are studies of overcomplete models. Those are the models of signals, on which is set for their parametrization more variables, than it's necessary and consequently there's computed so-called sparse solution via iteration algorithms. A goal of this analysis is a selection just of the considerable (sparse) parameters. The theory is based on a linear algebra, vector spaces, bases and so-called frames. The task of the individual project of this thesis is a description and simulation of two speech coders: a classical coder based on linear predictive speech coding and a coder, that's making use of overcomplete stochastic ARMA processes models. A part of their realization is to simulate their decoders and a analyze their reconstruction quality. For their realization there is used MATLAB and an overcomplete models' library (toolbox frames).
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Estimation of Fundamental Speech Frequency
Ráček, Tomáš ; Vlach, Jan (referee) ; Vondra, Martin (advisor)
The Bachelor thesis focuses on algorithms with respect to estimation of fundamental speech frequency. First part is introduce to the questions of speech signals and the thesis at this point gives a clue what the core is going to be about. In the second part the nature of speech signal is explained, as well as the process of it’s creation by a person and models for speech generation. In the chapter 3 processing of acoustic signals are described, where pre-processing, segmentation and application of Hamming window on the same acoustic speech signal are included. The next chapter reports on pitch speech frequency signal as a physical magnitude and it's derivation from the pitch period. Furthermore describes, fundamental frequency creation in speech organs, scale range for different people, properties that carries and finally possibilities of it’s usage. Chapter 5 deals with essential principles defining pitch speech frequency in time, frequency and cepstral domain. Chapter 6 contains description of principles, used in situations, where the speech signal is devalued by noise. In the next chapter author describes design and implementation of selected principle. Furthermore, author presents results that have been achieved with this specific principle and compares them to the results of ordinary autocorrelation principle. The final chapter summarises the thesis and discusses about possible further part, extension or improvement of the algorithm.
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Estimation of pitch period
Matuštík, Daniel ; Tučková, Jana (referee) ; Sigmund, Milan (advisor)
This diploma thesis with estimation of pitch period of the human voice. The paper listed some of the methods for Estimation of pitch period and method for preprocessing and final processing of the signal after application of functions to determine the frequency of the pitch period in graphical user interface.
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Sensorless velocity control and positions of d.c. low-power brush motor
Svoboda, Jan ; Hanák, Pavel (referee) ; Prajzner, Václav (advisor)
This bachelor's thesis focuses on sensorless control of low load brushed DC motor that is used in the actuators made by the Honeywell company. The first part provides an introduction into motor control and common used methods of speed and position sensing of brushed DC motor. Sensorless method of sensing described in this work is the detection of commutation pulses from the signal of motor current. These pulses are caused by brushes leaping over the commutator bars. Correct evaluation of commutation pulses can provide the information about velocity and position of the motor. This relatively new method of detection of commutation pulses is investigated and arising problems are demonstrated on measured samples of signal. Suitable methods of signal processing are then proposed. Infallibility of these signal processing methods is then proved on the set of signals measured under circumstances of supply voltage and abrasion. Then it is decided which signal processing method that sensorless control system can use is the best.
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Estimation and analysis of speech signal periodicity
Malucha, Jan ; Poměnková, Jitka (referee) ; Sigmund, Milan (advisor)
Theoretical part starts with a short introduction to speech signals and short time analysis method. Concept of periodicity is clarified. This is followed by analysis of the speech signal parameters - voiced/unvoiced classification, intonation and short time period similarity. Next the overview of methods used to analyze the mentioned parameters together with concepts of their algorithms is provided. These methods include ZCR, STE, HNR, ACF, NCC, AMDF and DTW. Algorithms using the methods with supporting preprocessing algorithms were programmed in MATLAB for practical part. All were tested on real speech signals and the results are discussed at the end of the thesis.
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LPC Speech Coding
Zapletal, Ondřej ; Kyselý, František (referee) ; Rajmic, Pavel (advisor)
The contents of the thesis "LPC speech coding" are studies of this method of a parametric source coding, explanation of mathematical procedures that are used in it (linear prediction, autocorrelation, Levinson-Durbin algorithm, transfer to a form suitable for transmission, Chebyshev root searching polynomial method) and acquaintance with the signification and application of that method in real speech encoders. The task of the original project of this thesis is a description and simulation of a simple speech encoder based on LPC, which transforms a real speech signal into a bit flow, which contains all of the significant parameters for its backward reconstruction (LSF coefficients, pitch period, excitation level, voice detection - AMDF method). One part of this thesis is a discussion about currently used speech encoders.
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Recognition of musical recordings
Masár, Igor ; Horka, Michal (referee) ; Sigmund, Milan (advisor)
This thesis analyzes the specific audio signal-music. It describes the basic methods of analysis of musical signals. The following are mentioned the most common music file formats and the possibility of cross transfer. There are explained terms of music theory, which are also present in this work. They are described and created three ways of detecting melody. It is selected optimal algorithm based on the successful detection of the reference melodies recordings. User interface is created in MATLAB GUI allows recognition of recordings. This interface is tested on few melodies.
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Influence of soil pretreatment on the determination of its properties using thermogravimetry
Ragačová, Lucia ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
This diploma thesis focuses on the influence of soil pretreatment on the determination of its properties by the method of thermogravimetry, which allows the soil sample to be analyzed as a whole. The aim is to clarify how soil preparation affects the results of TG soil analysis. Soil preparation can have a major impact on its quality and thus disrupt the interrelationships of soil components that have been formed as a result of long-term pedogenesis. In this thesis, therefore, the original soils were compared with the soils, which were grinded using a ball mill before the analysis, which represented a very intensive intervention in the soil structure and was therefore a mechanically disturbed soil. A modified method of deriving weight loss has been used to evaluate the issue. The data obtained were divided into 10°C thermal intervals, in-between which the loss of weight of the individual intervals were identified. The impact of soil milling on its determinability in relation to the total carbon and nitrogen content in the soil have been compared through the correlation of data obtained from elemental analysis and TG data. Subsequently, we focused on comparing the interrelationships of the equations of ground and unground soil samples, based on the theoretical equations of the issue. As a final look, we chose autocorrelation of TG data for the obtained ground and unground samples. The results of the examination have shown that even though grinding of samples represents a very intensive intervention into the soil structure and thus the soil is mechanically disturbed, such sample preparation has only a minimal effect on the determinability of soil properties.
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