| Titre : | The analysis of the pathological linear association degree of a phonocardiogram (PCG) signals by applying coherences |
| Auteurs : | Mohamed Rouis, Auteur ; abdelkrim ouafi, Directeur de thèse |
| Type de document : | Monographie imprimée |
| Editeur : | Biskra [Algerie] : Université Mohamed Kheider, 2019 |
| Langues: | Anglais |
| Mots-clés: | denoising operation,mother wavelet selection,optimal decomposition level,PCG signal |
| Résumé : | The recorded phonocardiogram PCG signal is often contaminated by different types of noises that can be seen in the frequency band of PCG signal, which may change the charac-teristics of this signal. Discrete wavelet transform ( DWT) has become one of the most important and powerful tools of signal representation, but its effectiveness is influenced by the issue of the selected mother wavelet and decomposition level (DL). The selection of DL and the mother wavelet are the main challenges. This work proposes a new approach for finding an optimal DL and optimal mother wavelet for PCG signals denoising. Our ap-proach consists of two algorithms are designed to tackle the problems of noise and variabil-ity caused by PCG acquisition in a real clinical environment for different categories of pa-tients whereas the obtained results are evaluated by examining coherence analysis, correla-tion coefficient, and in term of mean square error (MSE) and signal-to-noise ratio (SNR) in simulated noisy PCG signals. The experimental results show that the proposed method can effectively reduce noise. |
| Sommaire : |
General Introduction………………………………………….…………………….…..... i
Chapter 1 The physiological origin of heart sounds and murmurs 1.1 Introduction...…………………………………………………………..……….…….....3 1.2. Heart‟s Anatomy and Physiology..…………………………………………………......3 1.2.1. Heart Valves…… ………………………………………………………..…...…...5 1.2.2. Cardiac Cycle with Pressure Profile…………..……….………...……………........6 1.3 Digital Auscultation….………………………………………………………….…...7 1.3.1 Auscultation areas……………………………………………….…………..............7 1.3.2 Electronic stethoscope…………………………….…………………………..……9 1.3.3 Noise reduction in digital stethoscopes………..………………...…………...…....10 1.3.4 Noise analysis……………………………………...……………………………....10 1.3.5 Similar phonocardiogram ..………………………………………………....……..11 1.4 Sounds of Intracardiac Vibrations..……………………………………...……...…...…11 1.4.1 Timing of heart sounds..………………………………………..…………….……11 1.4.2 Heart Sounds..……………………………………………………………....…...…11 1.4.3 Heart sound analysis..…...………………………………………....……….......…..12 1.4.4 Splitting of heart sounds..……………………………………….……….........…....13 1.4.5 Abnormal Heart Sound or Heart Murmur..……………………………….....……13 1) Timing and duration..………………………………..……………………....….…14 2) Intensity..…………………………………………………………..….………...…14 3) Point of maximal intensity and radiation.……………………………...….………15 4) Shape.…………………………………………………………...……...……...……15 5) Character.……………………………………………………...…………...…...…15 (i) Systolic Murmurs..………………………………………………………...…..……16 Pansystolic Regurgitant Murmurs..…………………...…………..……......…17 Variants of the Pansystolic Regurgitant Murmur..………...……...……......…18 Early Systolic Regurgitant Murmurs………………………….....…..18 midsystolic and late systolic regurgitant murmurs………………......18 (ii) Diastolic Murmurs..……………………...…………………………...…...…..…....20 (iii) Continuous Murmurs..………………………………………...…...……...….....…21 (iv) Innocent murmurs..………………………………...…………………...……....…22 1.5 Conclusion..……………………………………………………………...………….….24 Chapter 2 Wavelet Transforms for signals 2.1 Introduction…………………………………………………………………………......26 2.2 Wavelet History……………………………………………………………………….. 26 2.3 Continuous Wavelet Transform………………………………………….…………… 26 2.4 Discrete Wavelet Transform (DWT)…………………………………….…………….30 2.5 Implementation of DWT………………………………………………………...……...31 2.5.1 Multiresolution Analysis (MRA)…………………………………………………. 32 2.5.2 The Detail Signal………………………………………………….……………… 33 2.5.3 Filter-bank Implementation of the Discrete Wavelet Transform……………….. 33 2.5.4 Perfect Reconstruction……………………………………………………….…….37 2.6 wavelets for analyzing PCG signals………….………………………………………...38 2.7 Basic wavelets and their properties ……………………………………………………39 2.8 Wavelet Families………………………………………………………………………..40 2.9 Conclusion……………………………………………………………………..………. 46 Chapter 3 The Usefulness of Wavelet Transform to Reduce Noise in the PCG Signal 3.1Introduction……………………………………………………………………………...48 3.2 Brief Overview of Discrete Wavelet Transform……………………………...………...48 3.3 Noise in Wavelet Domain…………………………………....…………………..…….. 48 3.4 Wavelet denoising……………………………………………………..………………. 49 3.5. Threshold selection rules..…………………………………………………………..49 3.5.1 Threshold rescaling methods…………………………………………….……….. 51 3.6. Thresholding functions………………………………………………………..….. 52 3.6.1 Classical Threshold Function…………………………………………………..….52 3.6 .2 The Improved Threshold Function…………………………………....………….52 3.7 Comparison assessments by denoising application…………………………………… 54 3.8 proposed approach for selecting DL and order……………………………………….. 54 3.8.1 Section (1)……………………………………….………………………………… 55 3.8.2 Section (2)…………………………………………………………...…………….. 56 3.9 Efficiency Criteria…………………………………...…………………………………..57 3.9.1 Correlation coefficient (Corr)………………………………………...…………… 58 3.9.2 Coherence (coh)…………………………………………...………………………. 58 3.10 Conclusion……..…………………………………….……………………………….. 58 Chapter 4 Experimental Results and Performance Evaluation 4.1 Introduction…………………………………………………………………………….60 4.2 Experimental Procedure ……………………………………………………………….60 4.3The evaluation of results by Correlation coefficient………………….………...……….67 4.4 The evaluation of results by coherence……………………………….………………...69 4.5 Conclusion………………………………………………………………………….........73 General Conclusion…………………………………………………………………….….. 75 Bibliographical references…………………………………………………………………..76 |
Disponibilité (1)
| Cote | Support | Localisation | Statut | Emplacement | |
|---|---|---|---|---|---|
| TH/0954 | Thèse de doctorat | BIB.FAC.ST. | Empruntable |
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