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Digital signal processing in real time
Zamazal, Zdeněk ; Mačák, Jaromír (referee) ; Rášo, Ondřej (advisor)
This work deals with digital signal processing in the field of adaptive filtering. Fundamental basics of adaptive filtering are described and primary aim is to create executable laboratory examples, using adaptive filtering, in LabView programming language. These laboratory examples are intended to be used by students fo studying and during laboratory lessons. Objective is to connect the examples with external devices, such as microphone. A microphone is used as an user's speech input acquiring interface. In the thesis is depicted Wiener's filter and problem of adaptive filtering is discussed. Contemporary adaptive algorithms are described and their applications as well. Most mentioned is the LMS algorithm and it's forms. Laboratory examples use following concepts: Adaptive Echo Cancellation, Active Noise Control and System Identification. Each of these examples is solely executable (need for LabView or Run-time engine), consisting also of theory with diagrams. Examples therefore are usable even without manual.
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Software implementation of the subjective assessments of sound quality
Špeta, Marek ; Balík, Miroslav (referee) ; Rášo, Ondřej (advisor)
The focus of this diploma thesis is on methods for the subjective assessment of sound quality according to recommandations given by International Telecommunication Union ITU. The thesis is thematically divided into four parts. The first part is an interpretation of methods based on internationally accepted standards (method of small impairments, MUSHRA, general methods). The second part describes the functional blocks of application developed for this thesis in LabVIEW enviroment. Next part explains its practical application, especially its running possibilities. The last part describes a listening experiment, aim of which was to verify the application's features and to compare the results of the subjective method used in the experiment with the results of the objective method PEAQ.
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Subjective assessment of disturbing noise from gramophone records
Vlašín, Martin ; Martinásek, Zdeněk (referee) ; Rášo, Ondřej (advisor)
The bachelor thesis is focused on distortion that occurs by playing gramophone records. Due to functional principle of turntable and due to origin of individual distortion, which may occur while playing records, were selected two most significant and most frequently occurring distortion. For these distortion is studied their effect on subjective assessment of audio record. From data obtained from participants in the listening test was performed statistical analysis, also test of reliability and detection of any possible errors occurring in the assessments of individual listeners. The conclusions from results confirmed differences between two distortions and also between different audio samples on the subjective perception of the quality of audio experience for listener.
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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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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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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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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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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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