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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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A Wavelet-Based QRS-Complex Detection
Kocian, Ondřej ; Provazník, Ivo (referee) ; Kozumplík, Jiří (advisor)
This project investigates methods of construction the wavelet-based QRS-complex detector. QRS-complex detection is very important, because it helps automatically calculate heart rate and in some cases it is used for compression ECG signal. The design of QRS detector can be made with many methods, in this project were mentioned and consequently tested only a few variants. The principle of designed detector used a wavelet-based decomposition of the original ECG signal to several frequency-coded bands. These bands are consequently transformed to absolute values and with the help of the threshold value are marked positions of assumed QRS complexes. Then are these assumed positions from all bands compared between themselves. If the position is confirmed at least at one nearby band, then is this position marked as true QRS complex. To increase efficiency of designed detector, two modifications were additionally mentioned. The first one, using the envelope of the signal, had rather negative effect on detectors efficiency. The second modification, using combined signal from three pseudoorthogonal leads, had reversely very good effect on detectors efficiency. In the end, the designed detector and all its modifications were tested on signals from CSE library (exactly on leads II, V2 and V6).
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Preprocessing of ECG signals for detection of significant points
Strouhal, Martin ; Smital, Lukáš (referee) ; Vítek, Martin (advisor)
This work aims to find out the best filter design method for getting out parasitic elements in ECG signal. There are defined origin and frequency qualities of these elements. Individua filter design methods are compared according to number of filter coefficients, effectivity and influenc to useful signal. I created several digital filters by various design methods and tested them on ten ECG signals. From the experiment ensued: all filters were able to get out brum, but filters designed by distribution of zeros and poles had the lowest number of coefficients. On the other hand same filters were disable to get out drift with very sheer course.
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ECG quality evaluation
Scholasterová, Viktorie ; Němcová, Andrea (referee) ; Smital, Lukáš (advisor)
This bachelor’s thesis deals with ECG quality evaluation. Its main goal is to examine the theoretical basis for a realization of selected methods for ECG quality evaluation. In the theoretical part of the thesis there is described electrocardiography, morphology of electrocardiogram, types of signal interference and Holter recorders. A basic procedure of ECG quality evaluation including filtration, detection of important characteristics of ECG signal and an overview of chosen methods follows. The practical part contains a description of three methods for ECG quality evaluation – a method of average heart rate, a method of calculation signal-to-noise ratio (SNR) and a method of band-pass filters. Finally, the results of the methods using artificial data, real-time data and data from a competition PhysioNet/Computing in Cardiology Challenge 2011 are evaluated.
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Automatic delineation of ECG signals
Olšanská, Eva ; Kozumplík, Jiří (referee) ; Vítek, Martin (advisor)
This bachelor´s thesis deals with the delineation of ECG signals. The aim of this bachelor´s thesis is to become familiar with ECG delineation and realize one chosen delineation method in Matlab. The delineation algorithm was tested on a CSE database. The theoretical part of the work describes methods of QRS complex detection and ECG delineation.
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Segmentation of ECG signals based on their quality
Zobačová, Barbora ; Maršánová, Lucie (referee) ; Vítek, Martin (advisor)
This semestral thesis deals with methods for continuous estimation of the quality of the ECG signal. The theoretical part includes the functional anatomy of the heart, the basics of electrocardiography, the types of noise that can be found in the ECG records, and a description of several methods for the continuous estimation of the ECG signal quality. Next here are some approaches to segmenting ECG signals based on their quality. The practical part deals with the implementation of two methods. The first method is the SNR estimation method based on the Wiener filter. The second method is the method of segmentation of ECG signals based on their quality. Both methods were tested on artificial and real signals.
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Automatic detection of myocardial infarction in ECG
Nejedlý, Lukáš ; Kozumplík, Jiří (referee) ; Smíšek, Radovan (advisor)
This master’s thesis deals with the automatic detection of myocardial infarction in ECG. Semester work consists of two parts. The theoretical part provides a description of the electrical conduction system of the heart, spreading of electrical activity through the heart muscle, the methods of ECG scanning and the ECG curve. There are also mentioned the causes of myocardial ischemia and various methods of its detection. Another part is devoted to high-frequency ECG, analysis of HFQRS and clinical studies which describe the use of high-frequency ECG in diagnosis of myocardial infarction. In the practical part is proposed an algorithm using low-frequency components ECG and an algorithm using high-frequency components ECG for automatic detection of myocardial infarction. The proposed algorithms are implemented in programming environment MATLAB and tested on signals from the PTB database. The final part of the master‘s thesis is devoted to the comparison of the success of myocardial infarction by means of low frequency and high frequency components of ECG and comparison of achieved results with results from clinical studies.
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HRV analysis in the context of daily activities
Indrák, Václav ; Smital, Lukáš (referee) ; Novotná, Petra (advisor)
The aim of this bachelors thesis is to measure ECG recordings on voulenteers, and following analysis of HRV from these recordings. It persues the explanation of basic metrics used to evaluate HRV, used both in clinical and scientific practice and their following programming implementation in Matlab environment to achieve the most accurate results possible, which are than assessed.
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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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Detection of QRS complex using leads transformation
Grossmann, David ; Kozumplík, Jiří (referee) ; Vítek, Martin (advisor)
The aim of this bachelor thesis is to become familiar with methods of detection of the QRS complex and the one chosen detection method realize by the Matlab. The detection of QRS is tested on a CSE database and the results are compared with other methods. The last part of this thesis is concerned with transformation leads methods between different lead systems.
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