National Repository of Grey Literature 70 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Detekce začátku a konce komplexu QRS s využitím hlubokého učení
Müller, Jakub ; Šaclová, Lucie (referee) ; Smíšek, Radovan (advisor)
ECG measurement isan essential diagnostic tool for cardiac health, and automation of its analysis can aid to our healthcare to relieve staff workload or improve the quality of automated diagnostics from wearable devices. This work focuses specifically on the QRS complex in the ECG signal, with the main goal of using deep learning methods to detect its onset and offset. In the theoretical introduction, the reader is introduced to the origin of the QRS complex and ECG measurements, artificial neural networks and deep learning. Modified architecture U-Net for 1D signals was chosen to implement the actual method. Data were extracted from five publicly available databases and preprocessed in Matlab. This was followed by moving to the Python environment where parts of the model were implemented using the TensorFlow and Keras libraries, subsequent training, testing of the model and evaluation of the results.
QRS complex detector in ECG signals
Kosíř, Kamil ; Vítek, Martin (referee) ; Smital, Lukáš (advisor)
The aim of this thesis is to introduce issues and basic principles of QRS complex detection in ECG signals. This work is separated into several parts. The first part deals with anatomy and functions of the heart, for example the emergence and spread of potentials. The next part includes distribution ECG leads and explanation of ECG signal. Afterwards are described some detectors of QRS complex. The main part of this work is realization of two algorithms implemented in Matlab program. The first detector is based on squaring algorithm and the the second is based on a spreading of the signal into several frequency bands. The effectivness of both detectors is tested on signals from CSE library at the end of the work.
QRS detection based on Stockwell transform
Kašík, Ondřej ; Kozumplík, Jiří (referee) ; Smital, Lukáš (advisor)
This bachelor´s thesis deals with the detection of QRS complexes in ECG record. The thesis provides a brief information related to the heart anatomy, generation of electrical signals in the heart, recording and description of the ECG record. In more detail, there is a description of the detection of QRS complexes by various methods and realization of a detector based on Stockwell transform, Shannon energy and adaptive thresholding. The evaluation process of the detection efficiency is also included. Sensitivity and positive prediction of the proposed detector on the complete MIT-BIH Arrhythmia database reached 99.80 % and 99.88 % respectively.
Automatic delineation of ECG signals
Jurek, Jakub ; Janoušek, Oto (referee) ; Vítek, Martin (advisor)
This project deals with basic description of ECG signal and some of known methods of delineation ECG´s individual parts. Next this work deals with detailed description of the method of authors Laguna, Jané, Caminal and realization of the complete delineation algorithm based on this method. Next this work deals with testing this algorithm on the CSE database, evaluation results and comparing results with results of authors of the method.
P wave detection in ECG signals
Bajgar, Jiří ; Kozumplík, Jiří (referee) ; Smital, Lukáš (advisor)
The aim of this diploma thesis is to introduce methods of detection of the QRS complex and the subsequent detection of P waves. The intention is to create a program by specified method in the software Matlab which will be able to implement this method. The thesis describes the basic and important methods of detection and subsequent algorithm to detect P waves. Solution of the algorithm is tested on real data. It also describes the automatic signal evaluation and the results of this automatic function.
Delineation of ECG signals using phasor transform
Koupil, Michal ; Vítek, Martin (referee) ; Maršánová, Lucie (advisor)
TThis project deals with delineation of ECG signals using phasor transform. This method is rather new in the field of automatic delineation of ECG and it is not widely used in practice yet. In the theoretical part, the relation between heart activity and ECG is described. A phasor transform is also described. In the practical part, a program was implemented in the computing environment of MATLAB. Its purpose is to delineate the signals. At first, it detects waves’ peaks, then its beginning and starting points. In the next part, analysis of the results is done, as well as comparison with other authors. The testing was performed on the QT signals from the Physionet database.
LabView and biosignal analysis
Kutílek, Miloš ; Harabiš, Vratislav (referee) ; Kolář, Radim (advisor)
This bachelor’s thesis deals with the analysis of biological signals in LabView environment. Mainly it focuses on the analysis of ECG signals. The thesis also describes the theory of electrocardiogram and occupies by several programs which consider various approaches to digital filtering of ECG signals, programs for detection R wave by different ways and simple cardiology monitor.
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).
QRS detection using zero crossing counts
Kašák, Pavel ; Hrubeš, Jan (referee) ; Vítek, Martin (advisor)
This thesis is focusing on problems of detection of QRS complex. It includes basic description of ECG signal. It acquaints with common methods of searching QRS complex. Main attention is paid to detection based on zero crossing counts, which is realized by MATLAB program. This algorithm is then tested on CSE database, optimised and its efficiency is evaluated.
QRS detection based on wavelet transform
Zedníček, Vlastimil ; Ronzhina, Marina (referee) ; Smital, Lukáš (advisor)
This thesis deals with implementation of detector QRS complex with use of wavelet transform. The first part is focused on formation and possibility to measure cardiac activity. The other part of thesis we will familiarise with the different possibilities of detection QRS complex and we intimately focus on wavelet transform that will be used for a project of detection QRS complex. The practical part of thesis focuses on the project of detector in programming language Matlab and his different setting. This projected detector has been tested with CSE database. Achieved results of projected detector are evaluated with the results of others authors.

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