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Processing of heart sounds signals
Němcová, Simona ; Matějková, Magdaléna (referee) ; Vondra, Vlastimil (advisor)
This bachelor thesis is focused on the heart sound signal. It describes the principles of hear sound formation, measurement methods and especially the analysis of the measured phonocardiography signal. In the practical part of this thesis, the algorithm for detecting the first and the second heart sounds is designed by using MATLAB software. Its principle is realized in finding maximum or center of gravity in the filtered phonocardiography signal.
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Measurement of ECG signal for TWA analysis
Řezáč, Petr ; Vítek, Martin (referee) ; Kozumplík, Jiří (advisor)
The thesis deals with possibilities of using wavelet transform in the field of surface electrocardiogram (ECG) signals denoising and ECG signals measuring. Several algorithms have been used to detect and estimate T-wave alternans (TWA), such as spectral method (SM), Poincaré Mapping (PM) or correlation method (CM). T-wave alternans, also called repolarization alternans, is a phenomenon appearing in the electrocardiogram as a consistent fluctuation in the repolarization morphology on every-other-beat basis. Electrical TWA has been recognized as a marker of electrical instability, and has been shown to be related with patients at increased risk for ventricular arrhytmias. Presence of TWA has been reported in a wide range of clinical and experimental situations including long QT syndrome, myocardial infarction, angina pectoris, acute ischemia, etc. Projected methods of detection TWA are realized in Matlab software, and they are experimentally verified on real ECG signals from the European ST-T Database.
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Speckle noise suppression methods in ultrasound images
Tvarůžek, Marek ; Harabiš, Vratislav (referee) ; Mézl, Martin (advisor)
This diploma thesis deals with the methods of despeckling in ultrasound images. Ultrasound imaging and related artifacts are described in more details. Ultrasound imaging has its pros and cons, where speckle noise is a disadvantage to be solved. Models of origin of this specific noise are referred too. Practical part of this thesis aims on filtering speckled images by basic and advanced filtering methods as are linear filtering, median filtering, application of Frost filter, QGDCT, geometric filtering, anisotropic diffusion filtering and filtering based on wavelet transformation. Results are compared on the basis of objective criteria.
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Time-Frequency Signal Analysis
Kubala, Matej ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This bachelor thesis is dealing with explanation of time-frequency signal analysis. Basic definitions and terms of signal processing and spectral analysis will be explained, especially focused on transfer time domain into freqency and inverse. The main objective of thesis is to explain in detail and compare two of the most popular methods, Fourier transform and Wavelet transform. Results will be illustrated on implemented application, which loads sound record and computes frequency in specific time using these methods.
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Modern methods of QRS detection
Fajkus, Jiří ; Kozumplík, Jiří (referee) ; Vítek, Martin (advisor)
This bachelor’s thesis deals with methods, which are used for processing of ECG signals, specifically for the detection of QRS complexes. The QRS detection is an essential part of every ECG analysis because it is a source of points with timing information, which are used for classification and measurement of other waves and intervals required for diagnostics. Some ways of QRS detection are described in this work and there is also a description of detector implemented in programming environment MATLAB, which is based on zero crossing counts. This QRS detector was then tested CSE database and signals from Holter examination.
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ECG noise influence on compression using SPIHT algorithm
Bartošovský, Petr ; Vítek, Martin (referee) ; Hrubeš, Jan (advisor)
The thesis provides an analysis of the ECG signal, focusing on the possible types of interference occuring in the signal. These types of interference are closely examined and their realization in the MATLAB programming environment is characterized. The SPIHT algorithm is introduced and the possibilities of its use are discussed. Futher, the application of this algorithm to the ECG signal containing individual types of interference generated by means of the designed interference generator is described and the impact of the SPIHT algorithm on the specific types of signal interference is analyzed. Finally, the obtained results are evaluated.
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Restoration of overexposed digital image
Zonygová, Kristýna ; Veselý, Vítězslav (referee) ; Rajmic, Pavel (advisor)
The Bachelor thesis deals with the recovery of overexposed grayscale images based on sparse signal representation. For image conversion to another representation wavelet transform was used. In this representation, the solution of convex optimization which demand on relax signal sparse and restored pixels values was searched for. In this case, the proximal Douglas-Rachford algorithm was applied which uses two proximal operators. The implementation was carried out in numerical computing enviroment MATLAB using the Wavelet Toolbox software. The PSNR (peak signal-to-noise ratio) was utilized to evaluate success rate of proposed method. The method was tested on 5 random images and compared to results of image manipulation software Adobe Photoshop Lightroom CC.
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Restoration of overexposed digital image
Zonygová, Kristýna ; Veselý, Vítězslav (referee) ; Rajmic, Pavel (advisor)
The Bachelor thesis deals with the recovery of overexposed grayscale images based on sparse signal representation. For image conversion to another representation wavelet transform was used. In this representation, the solution of convex optimization which demand on relax signal sparse and restored pixels values was searched for. In this case, the proximal Douglas-Rachford algorithm was applied which uses two proximal operators. The implementation was carried out in numerical computing enviroment MATLAB using the Wavelet Toolbox software. The PSNR (peak signal-to-noise ratio) was utilized to evaluate success rate of proposed method. The method was tested on 5 random images and compared to results of image manipulation software Adobe Photoshop Lightroom CC.
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Processing of heart sounds signals
Němcová, Simona ; Matějková, Magdaléna (referee) ; Vondra, Vlastimil (advisor)
This bachelor thesis is focused on the heart sound signal. It describes the principles of hear sound formation, measurement methods and especially the analysis of the measured phonocardiography signal. In the practical part of this thesis, the algorithm for detecting the first and the second heart sounds is designed by using MATLAB software. Its principle is realized in finding maximum or center of gravity in the filtered phonocardiography signal.
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Time-Frequency Signal Analysis
Kubala, Matej ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This bachelor thesis is dealing with explanation of time-frequency signal analysis. Basic definitions and terms of signal processing and spectral analysis will be explained, especially focused on transfer time domain into freqency and inverse. The main objective of thesis is to explain in detail and compare two of the most popular methods, Fourier transform and Wavelet transform. Results will be illustrated on implemented application, which loads sound record and computes frequency in specific time using these methods.
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