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Real-time spectral analysis in LabVIEW software environment
Vašátko, Karel ; Průša, Zdeněk (referee) ; Rášo, Ondřej (advisor)
This bachelor thesis deals with issues of signal processing and display its spektrum in the environtment LabVIEW. Here is description signal processing theory, description of a block diagram of a spectral analysis and description of the methods for compute power spectral density. In the main part is a description of program developed for real-time spectral analysis. Part contains block diagrams and measurements.
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Design and Realization of Modification of Acoustic Field in Laboratory
Ješko, Petr ; Rášo, Ondřej (referee) ; Schimmel, Jiří (advisor)
The thesis deals with the problems of closed spaces. It deals with situations where it is necessary to reduce the reverberation time in certain octave bands. It provides procedures comparing conventional method of solving by calculation of the mean sound absorption coefficient of the area and the subsequent experimental addition of acoustic absorbers which occupy different areas and method that uses an acoustic simulation software for the 3D model. It also deals with a concept of Reflection Phase Grating diffuser.
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Objective assessment and reduction of noise in musical signal
Rášo, Ondřej ; Makáň, Florian (referee) ; Krejčí, Jiří (referee) ; Balík, Miroslav (advisor)
The dissertation thesis focuses on objective assessment and reduction of disturbing background noise in a musical signal. In this work, a new algorithm for the assessment of background noise audibility is proposed. The listening tests performed show that this new algorithm better predicts the background noise audibility than the existing algorithms do. An advantage of this new algorithm is the fact that it can be used even in the case of a general audio signal and not only musical signal, i.e. in the case when the audibility of one sound on the background of another sound is assessed. The existing algorithms often fail in this case. The next part of the dissertation thesis deals with an adaptive segmentation scheme for the segmentation of long-term musical signals into short segments of different lengths. A new adaptive segmentation scheme is then introduced here. It has been shown that this new adaptive segmentation scheme significantly improves the subjectively perceived quality of the musical signal from the output of noise reduction systems which use this new adaptive segmentation scheme. The quality improvement is better than that achieved by other segmentation schemes tested.
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Implementation of edge detector using wavelet transform
Pálka, Zbyněk ; Rášo, Ondřej (referee) ; Růčka, Lukáš (advisor)
This thesis is focused on edge detection in image. In theoretical part are contained genarally used methods of edge detection using first and second-order derivate and both of mentioned methods are described here. Further it’s deiscribed here continuous, descrete and two dimensional descrete wavelet transform and process of noise removing in image by descrete wavelet transform. In next part are analysed two methods of edge detection using wavelet transform and their possible realizations in program Matlab. In practical part of thesis is in detail described algorithm of program on edge detection using wavelet transform and it‘s described here individual functions of program. The main content of practical part are visual results of wavelet edge detector and their comparison with Canny, Prewitt and Sobel edge detector.
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Establishment of database of musical instruments recordings
Lavický, Vojtěch ; Mácha, Tomáš (referee) ; Rášo, Ondřej (advisor)
In this Bachelor thesis you can find created database of musical instruments. Recordings are descripted by it's waveforms and sectrograms. It may serve for example for removing noise from signal. A general data of instruments are descripted here. Human earing and his perception of sound is discuss here. There are also included parameters of sound itself and theory of calculations. Frequency and dynamic range are written to every instrument in database. These are consequently range by its size. As a part of the thesis is program with graphical user interface. The program include all the recordings from database and is open to any other recordings.
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Communication protocol for messenger
Bílý, Ondřej ; Rášo, Ondřej (referee) ; Mlýnek, Petr (advisor)
Bachelor‘s discuss on theme Communications protocol for messenger and his security. The introduction analysis the basic points of cryptographic security of data. Next two parts deals with the two most used architectures in the area of information network, which helps in understanding of sending data by this network. Penult deals with the creation of the communication channel in between the applications in the information network.. The final part includes description of three uncomplicated applications. This demonstrates the use of various cryptographic securities and various protocols for the sending of information between the users.
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Methods for automated camera focusing
Kičina, Pavol ; Rášo, Ondřej (referee) ; Šmirg, Ondřej (advisor)
This bachelor´s thesis is about methods of focusing with web camera. Edge detection method and Discrete cosine transform method are use in this thesis. In program MatLab I create a program, which take a picture from web camera. With handle focusing this program shows information how much is picture focus. Functional and elementary are subject, which I use to compare. Advantages and disadvantages are in this thesis, with important elements about quality of focus,too.
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Implementation of symmetric bloc cipher AES in modern processors
Škoda, Martin ; Balík, Miroslav (referee) ; Rášo, Ondřej (advisor)
The main aim of master's thesis is usage of new instructions from instruction set called Intel® Advanced Encryption Standard New Instructions (AES-NI), which is available on processors with code name Westmere and newer. In theoretical part, there are described symmetric block ciphers and their operational modes. Cipher AES is described in details, especially used block transformations, key expansion and equivalent inverse cipher. Next topic is description of instructions of AES-NI instruction set – their function is explained using pseudo codes of instructions and there are examples of their usage in code. Further in work, dynamic-link library is created, which implements cipher AES with key sizes 128, 192 and 256 bites and implements operational modes described in theoretical part. Library functions are called from Matlab by scripts and their functionality is proved by checking test vectors values, which are provided in publications of National Institute of Standards and Technology.
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Using Hilbert Huang transformation for analysis of non-stationary signals from physical experiments
Tuleja, Peter ; Balík, Miroslav (referee) ; Rášo, Ondřej (advisor)
This paper discusses the possible use of Hilbert-Huang transform to analyze the data obtained from physical experiments. Specifically for the analysis of acoustic emission in the form of acoustic shock. The introductory section explains the concept of acoustic emission and its detection process. Subsequently are discussed methods for signal analysis in time-frequency domain. Specifically, short-term Fourier transform, Wavelet transform, Hilbert transform and Hilbert-Huang transform. The final part contains the proposed method for measuring the performance and accuracy of different approaches.
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