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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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Beamforming using microphone arrays
Bartoň, Zdeněk ; Schimmel, Jiří (referee) ; Míča, Ivan (advisor)
The aim of the master thesis is to sum up theoretical information about beamforming methods of microphone arrays and to verify their functionality. At the beginning of this work there are simulated different varietes of linear uniform and nonuniform microphone arrays and circular arrays. The results are verificated by a practical measurement in ideal conditions. Then I will focuse on implementation of the DAS(Delay And Sum), SAB(Sub Array Beamforming), CDB(Constant Directivity Beamforming), CDB-CA(CDB-Circular Arrays) beamformer including theoretical and practical verification of the functionality in ideal conditions. At the end of this thesis are all beamforming methods compared with each other at SNR(signal to Noise Ratio) and directivity parameters.
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Methods for detecting acoustic sources using microphone arrays
Durkoš, Michal ; Rampl, Ivan (referee) ; Míča, Ivan (advisor)
his paper denotes various possibilities of localization of sources of acoustic signals. It informs the reader about possibilities of using beamforming and it´s basic conditions and rules. In detail it denotes delay-and-sum beamforming, which can be used for both localization of signal sources and for improving the signal by extending signal-to-noise ratio. In the last part of this paper process of simulation of incidence of sound signal on the microphone array is shown, experimental measures are noted and so is their evaluation.
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Localization of moving acoustical sources
Bezdíček, Martin ; Rampl, Ivan (referee) ; Míča, Ivan (advisor)
This master's thesis is focused on localization static (entering semester project) and moving acoustic sources (entering master's thesis) by the help of microphonic arrays. In the first part deal with common problems of localization. Further are here described types of microphonic arrays, simplifying possibilities which delimited this problems and general information about room acoustics. In the next part of this master's thesis are step by step mentioned methods localization of acoustic sources. In practical part were used algorithms: Steered-Beamformer-Based Locators and TDOA-Based Locators. Last part of this master's work includes results of these algorithms.
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Noise Source Identification Using Nearfield Acoustical Holography
Nevole, Tomáš ; Míča, Ivan (referee) ; Schimmel, Jiří (advisor)
This master’s thesis deals with problems of noise source identification using nearfield acoustical holography (NAH). In the beginning there is the summary of basic terms and values of a sound pressure field, which is unnecessary for understanding of the theme. In the next part the thesis continues with more detailed description of the NAH technology and the historical context of its emergence. Measurement equipment which is used for scanning of sound pressure fields is also introduced. In addition, the kinds of NAH (according the shape of the wave front) are showed and the planar NAH is descripted most closely. Because of the NAH algorithms are implemented in the wave number domain (k-space), there is also a chapter focused to this problem in the thesis. There are briefly descripted some similar methods in next chapter, like statistically optimized NAH, (SONAH) and iterative NAH with recursive filtration. The main product of the thesis is the practical part represented by testing application. That is created in the Matlab environment and is able to calculate and display hologram of the scanned array by the planar NAH method using the “k-space” filter. The application supposes a planar sound source and in other cases the accuracy of the reconstruction is not guaranteed. There are also given some holograms calculated with the application.
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Assessment of speech signal quality
Tuleja, Peter ; Balík, Miroslav (referee) ; Míča, Ivan (advisor)
This paper discusses methods for evaluating the quality of the speech signal. Briefly describe the subjective methods for determining the quality of the speech signal. From subjective methods the pair-wise comparison and MOS score are presented. Objective intrusive methods are described in more detailed way - namely methods of the segmental SNR evaluated in time domain, method of the segmental SNR evaluated in the frequency domain and frame normalization method which uses LSE based estimator. At the end of this paper is described an experiment, in which the aforementioned methods are compared and than statistically evaluated.
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Eye blink detection and recognition
Tesárek, Viktor ; Míča, Ivan (referee) ; Vlach, Jan (advisor)
This master thesis deals with the issues of the eye blink recognition from video. The main task is to analyse algorithms dealing with a detection of persons and make a program that could recognize the eye blink. Analysis of these algorithms and their problems are in the first part of this thesis. In the second part design and properties of my program are described. The realization of the program is based on the method of move detection using the accumulated difference frame, which helps to identify the eye areas. The eye blink detection algorithm tests a match between a tresholded pattern of the eye area taken from the actual frame and the frame before. The resolution whether the eye blink happened or not, is based on the level of the match. The algorithm is designed for watching a sitting man, which is slightly moving. The background can be a little dynamic as well. An average quality video with a moderator and dynamic backround was used as a tested subject.
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Microphone arrays for beamforming
Grénar, Milan ; Smékal, Zdeněk (referee) ; Míča, Ivan (advisor)
The aim of the bachelor's thesis is to assemble theoretical and practical information about methods for estimate direction of arrival whereas there is an emphasis on beamforming. There are introduced general conventions which are being used to measure with multichannel microphone array. Part of this thesis is the implementation of the DAS beamformer in several modifications, including verification of the functionality in ideal and real conditions.
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Neural networks in speaker classification
Svoboda, Libor ; Atassi, Hicham (referee) ; Míča, Ivan (advisor)
The content of this work is focused on the neural network per speaker recognition. The work deals with problems of processing speech signal and there are introduction some types of neural network. The part of work was made database of records from speakers with have various sex and ages. The train and test group was made from the database. For classifier were suggested afterwards. One of them was nominated on base Gaussian mixture model and three of them were nominated on neural. This system was tested and analyzed on the basis of age, gender and both criterions each other at the end. Attention is focused on choice suitable feature in each mission of classification at the same time. At the end of work are introduced results of analysis for individual groups and features. The most suitable features are diagnosed from given mission of classification and the most prosperous classifier.
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