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Fast Digital filters for ECG Signals
Ráček, Tomáš ; Vítek, Martin (referee) ; Kozumplík, Jiří (advisor)
In the thesis there are described the implementations of various types of filters to remove disturbing signals, which often degrade the ECG signal. In particular, it is a zero isoline fluctuations and power network interference. It is used a principle of the Lynn’s linear filters. The individual filters are designed in a recursive and non-recursive implementation. Then there is described a time-varying linear Lynn's filter for removing drift of zero isoline signal. The thesis also includes filters with minimized calculating time of response, by sampling rate conversion method for both interference types. In conclusion there is an experimental study of the filter implementation for ECG signal with false and real interferences.
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Digital filters - learning simulation
Hampl, Lukáš ; Pikula, Stanislav (referee) ; Šedivá, Soňa (advisor)
This thesis focuses on the theoretical analysis and application of methods of the two basic types of the digital filters designs. The specific digital filters in this bachelor’s thesis are filters FIR (final impulsive response) and IIR (infinite impulsive response). The main aim in this bachelor’s thesis is, besides the theoretical analysis about the digital filtration, to create a program in the LabVIEW. A user can design digital filters of both types with the help of this program. This program should serve as a learning tool for students to easier understand the problematics of the digital filtration. The emphasis is on the possibility of the design of both filters when user can try how each property is changed with the slightest change of settings. Apart from the filtration of the own input signal, the reciprocal comparison of the both digital filters according to a few criteria is very important.
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Human Sleep EEG Analysis
Sadovský, Petr ; Rozman, Jiří (advisor)
This thesis deals with analysis and processing of the Sleep Electroencephalogram (EEG) signals. The scope of this thesis can be split into several areas. The first area is application of the Independent Component Analysis (ICA) method for EEG signal analysis. A model of EEG signal formation is proposed and conditions under which this model is valid are examined. It is shown that ICA can be used to remove non-deterministic artifacts contained in the EEG signals. The second area of interest is analysis of stationarity of the Sleep EEG signal. Methods to identify stationary signal segments and to analyze statistical properties of these stationary segments are presented. The third area of interest focuses on spectral analysis of the Sleep EEG signals. Analyses are performed that shows the processes that form particular parts of EEG signals spectrum. Also, random signals that are an integral part of the EEG signals analysis are performed. The last area of interest focuses on elimination of the transition processes that are caused by the filtering of the short EEG signal segments.
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Delineation of ECG signals using methods combining
Zahradník, Radek ; Smital, Lukáš (referee) ; Vítek, Martin (advisor)
The aim of this work is to study and describe the principles and method of delineation of ECG signals. Learn and describe about method of cluster analysis. In this work was created and described three different methods of delineations of ECG signals. Created algorithms were tested on complete CSE database. With cluster analysis were combine created methods. The obtained results from realized methods and combined method were compared with others known methods. At the end of this work is evaluate efficiency of detection of combined method.
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Digital filtering of ECG signals
Ráček, Tomáš ; Kolář, Radim (referee) ; Kozumplík, Jiří (advisor)
In the thesis there are presented frequency features of disturbing signals as baseline fluctuation, power network interference and myopotentialstion. Methods for removing these signále are discussed too. It iis used a principle of the Lynn’s linear filters, mostly the Lynn’s high pass and Lynn’s band pass filters. For real-time ECG signal filtration there is optimal to use the filter with continuously changing cut-off frequency according to a measured heart rate. Then there is described a simple dynamic linear Lynn's filter with a varying impulse response according to the heart rate.
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Digital filtration in 8-bit microcontrollers
Záplata, Filip ; Frýza, Tomáš (referee) ; Fedra, Zbyněk (advisor)
The aim of my bachelor’s thesis is a digital filtration using the 8-bit processors. Digital filters are in use a lot and gradually outdoing analog equivalents. Their advantages are indisputable, but computing still inhibits bigger progress. Generally used microcontrollers do not have very powerfull core, so there is effort to apply as bright as possible algorithms. Program code can be written in C language or assembler eventually is possible to combine both languages. The task is to make a library of functions based on some powerfull algorithms for filtering. Testing those libraries and comparing their useability focused on maximal speed and universality of use and review ways of programming.
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Digital filtering of ECG signals
Ráček, Tomáš ; Kolář, Radim (referee) ; Kozumplík, Jiří (advisor)
The aim of the thesis is to out¬line the present state of digital pre¬processing (especially filtering) of ele¬ctrocardiograms. The frequency featu¬res of disturbing signals (baseline wandering, power network interferan¬ce, myopotentials) are mentioned and methods for removing of them are discussed. Based on this description, requirements for amplitude characterization of phase non-distorting filter for sup¬pressing the drift of isoelectric line of ECG signal are tentatively established. Several digital filters were created so that their application in testing would enable to give even more precision to requirements for amplitude characteristics. The expriments made it clear that ECG sig¬nal may be filtered through high pass filter with linear phase characteristic and cutt-off frequency 0.7 Hz and mi¬ximum attentuation in the filter transmission band 0.5 dB irrespective of rhythm regularity without significant distortion to occur. Also is describe an experiment by means of which they assessed the width of the frequency band of the ideal, not distorting band-stop filter for the suppression of the network hum in the ECG signal. It was found that the width of the band can be as much as +-3 Hz in the area surrounding the network frequency without cau¬sing excessive distortion of the useful signal. Also are discuss the properties, design and inlplementation of band-stop filters, based on the principle of Lynn's filters. It is optimal to use the filter with its cut-off fre¬quency continually changing according to measured heart rate for pre-processing ECG signal to decrease baseline drift by high-pass filter in real time. Easy rea¬lizable non-recursive Lynn's filter with time-varying impulse response adapted to the current frequently of ECG signal is described.
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Digital filtering of ECG signals
Ráček, Tomáš ; Kolář, Radim (referee) ; Kozumplík, Jiří (advisor)
The aim of the thesis is to out¬line the present state of digital pre¬processing (especially filtering) of ele¬ctrocardiograms. The frequency featu¬res of disturbing signals (baseline wandering, power network interferan¬ce, myopotentials) are mentioned and methods for removing of them are discussed. Based on this description, requirements for amplitude characterization of phase non-distorting filter for sup¬pressing the drift of isoelectric line of ECG signal are tentatively established. Several digital filters were created so that their application in testing would enable to give even more precision to requirements for amplitude characteristics. The expriments made it clear that ECG sig¬nal may be filtered through high pass filter with linear phase characteristic and cutt-off frequency 0.7 Hz and mi¬ximum attentuation in the filter transmission band 0.5 dB irrespective of rhythm regularity without significant distortion to occur. Also is describe an experiment by means of which they assessed the width of the frequency band of the ideal, not distorting band-stop filter for the suppression of the network hum in the ECG signal. It was found that the width of the band can be as much as +-3 Hz in the area surrounding the network frequency without cau¬sing excessive distortion of the useful signal. Also are discuss the properties, design and inlplementation of band-stop filters, based on the principle of Lynn's filters. It is optimal to use the filter with its cut-off fre¬quency continually changing according to measured heart rate for pre-processing ECG signal to decrease baseline drift by high-pass filter in real time. Easy rea¬lizable non-recursive Lynn's filter with time-varying impulse response adapted to the current frequently of ECG signal is described.
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