A phonocardiographic-based fiber-optic sensor and adaptive filtering system for noninvasive continuous fetal heart rate monitoring

This paper focuses on the design, realization, and verification of a novel phonocardiographic-based fiber-optic sensor and adaptive signal processing system for noninvasive continuous fetal heart rate (fHR) monitoring. Our proposed system utilizes two Mach-Zehnder interferometeric sensors. Based on the analysis of real measurement data, we developed a simplified dynamic model for the generation and distribution of heart sounds throughout the human body. Building on this signal model, we then designed, implemented, and verified our adaptive signal processing system by implementing two stochastic gradient-based algorithms: the Least Mean Square Algorithm (LMS), and the Normalized Least Mean Square (NLMS) Algorithm. With this system we were able to extract the fHR information from high quality fetal phonocardiograms (fPCGs), filtered from abdominal maternal phonocardiograms (mPCGs) by performing fPCG signal peak detection. Common signal processing methods such as linear filtering, signal subtraction, and others could not be used for this purpose as fPCG and mPCG signals share overlapping frequency spectra. The performance of the adaptive system was evaluated by using both qualitative (gynecological studies) and quantitative measures such as: Signal-to-Noise Ratio-SNR, Root Mean Square Error-RMSE, Sensitivity-S+, and Positive Predictive Value-PPV.Web of Science174art. no. 89

Performance Analysis of Fetal-Phonocardiogram Signal Denoising Using The Discrete Wavelet Transform

The obligation for comprehensive fetal heart rate investigation had driven to improve the passive and non-invasive diagnostic instruments despite the USG or CTG method. Fetal phonocardiography (f-PCG) utilizing the auscultation method met the above criteria, but its interpretation frequently disturbed by the presence of noise. For instance, maternal heart and body organ sounds, fetal movements noise, and ambient noise from the environment where it is recording are the noise that corrupted the f-PCG signal. In this work, the use of discrete wavelet transforms (DWT) to eliminate noise in the f-PCG signal with SNR as the performance parameters observed. It was observing the effect of changes in wavelet type and threshold type on the SNR value. The test was carried out on f-PCG data taken from physio.net. Initial SNR values ranged from -26.7 dB to -4.4 dB; after application of DWT procedure to f-PCG, SNR increased significantly. Based on the test results obtained, wavelet type coif1 with the soft threshold gave the best result with 11.69 dB in SNR value. The coif1 had a superior result than other mother wavelets that use in this work, so the fPCG signal analysis for fetal heart rate investigation suggested to use it.The obligation for comprehensive fetal heart rate investigation had driven to improve the passive and non-invasive diagnostic instruments despite the USG or CTG method. Fetal phonocardiography (f-PCG) utilizing the auscultation method met the above criteria, but its interpretation frequently disturbed by the presence of noise. For instance, maternal heart and body organ sounds, fetal movements noise, and ambient noise from the environment where it is recording are the noise that corrupted the f-PCG signal. In this work, the use of discrete wavelet transforms (DWT) to eliminate noise in the f-PCG signal with SNR as the performance parameters observed. It was observing the effect of changes in wavelet type and threshold type on the SNR value. The test was carried out on f-PCG data taken from physio.net. Initial SNR values ranged from -26.7 dB to -4.4 dB; after application of DWT procedure to f-PCG, SNR increased significantly. Based on the test results obtained, wavelet type coif1 with the soft threshold gave the best result with 11.69 dB in SNR value. The coif1 had a superior result than other mother wavelets that use in this work, so the fPCG signal analysis for fetal heart rate investigation suggested to use it

Novel hybrid extraction systems for fetal heart rate variability monitoring based on non-invasive fetal electrocardiogram

This study focuses on the design, implementation and subsequent verification of a new type of hybrid extraction system for noninvasive fetal electrocardiogram (NI-fECG) processing. The system designed combines the advantages of individual adaptive and non-adaptive algorithms. The pilot study reviews two innovative hybrid systems called ICA-ANFIS-WT and ICA-RLS-WT. This is a combination of independent component analysis (ICA), adaptive neuro-fuzzy inference system (ANFIS) algorithm or recursive least squares (RLS) algorithm and wavelet transform (WT) algorithm. The study was conducted on clinical practice data (extended ADFECGDB database and Physionet Challenge 2013 database) from the perspective of non-invasive fetal heart rate variability monitoring based on the determination of the overall probability of correct detection (ACC), sensitivity (SE), positive predictive value (PPV) and harmonic mean between SE and PPV (F1). System functionality was verified against a relevant reference obtained by an invasive way using a scalp electrode (ADFECGDB database), or relevant reference obtained by annotations (Physionet Challenge 2013 database). The study showed that ICA-RLS-WT hybrid system achieve better results than ICA-ANFIS-WT. During experiment on ADFECGDB database, the ICA-RLS-WT hybrid system reached ACC > 80 % on 9 recordings out of 12 and the ICA-ANFIS-WT hybrid system reached ACC > 80 % only on 6 recordings out of 12. During experiment on Physionet Challenge 2013 database the ICA-RLS-WT hybrid system reached ACC > 80 % on 13 recordings out of 25 and the ICA-ANFIS-WT hybrid system reached ACC > 80 % only on 7 recordings out of 25. Both hybrid systems achieve provably better results than the individual algorithms tested in previous studies.Web of Science713178413175

A Comparative Analysis of Fetal Phonocardiograph Acoustical Performance

Táto bakalárska práca sa zaoberá komparatívnou analýzou elementárnych častí fetálneho fonokardiografu pomocou časovo-frekvenčnej analýzy fetálneho fonokardiografického signálu (fFKG). Fetálny FKG signál je ovplyvnený rôznymi aspektami akými sú pohyb senzora, okolitý hluk, pohyb plodu, materské zvuky, časti, z ktorých je fetoskop zložený atď. Práca sa v úvode zaoberá plodovým srdcom a jeho akustickou činnosťou, v ktorej sú popísané jednotlivé srdcové ozvy. Následne sa práca zaoberá problematikou monitorovania plodového srdca. Na problematiku monitorovania nadväzuje rešeršná časť, ktorá popisuje históriu ale aj nové možnosti snímania fFKG signálu. Na základe rešeršnej časti sú testované a analyzované jednotlivé elementárne časti fetálneho fonokardiografu na syntetických dátach, ktoré sú následne vyhodnotené. Na základe týchto výsledkov je navrhnuté najideálnejšie zloženie fetálneho fonokardiografu, ktorý je testovaný na tehotnej žene v 34.týždni tehotenstva.This thesis deals with comparative analysis of elementary parts of fetal phonocardiograph by time-frequency analysis of fetal phonocardiographic signal (fFKG). The fetal FKG signal is affected by various aspects such as sensor movement, ambient noise, fetal movement, maternal sounds, elementary parts of a fetoscope and so on. The thesis also deals with the fetal heart and its acoustic activity, in which the heart sounds are described. Subsequently, the thesis deals with the issue of monitoring the fetal heart. The issue of monitoring is followed by a research section, which describes the history and new possibilities of sensing fFKG signal. Based on the research part, elementary parts of fetal phonocardiograph are tested, analyzed and subsequently evaluated. Based on these results, the most ideal composition of fetal phonocardiography is designed and tested on a pregnant woman at 34th weeks of pregnancy.450 - Katedra kybernetiky a biomedicínského inženýrstvívelmi dobř

Non-invasive fetal monitoring: a maternal surface ECG electrode placement-based novel approach for optimization of adaptive filter control parameters using the LMS and RLS algorithms

This paper is focused on the design, implementation and verification of a novel method for the optimization of the control parameters (such as step size mu and filter order N) of LMS and RLS adaptive filters used for noninvasive fetal monitoring. The optimization algorithm is driven by considering the ECG electrode positions on the maternal body surface in improving the performance of these adaptive filters. The main criterion for optimal parameter selection was the Signal-to-Noise Ratio (SNR). We conducted experiments using signals supplied by the latest version of our LabVIEW-Based Multi-Channel Non-Invasive Abdominal Maternal-Fetal Electrocardiogram Signal Generator, which provides the flexibility and capability of modeling the principal distribution of maternal/fetal ECGs in the human body. Our novel algorithm enabled us to find the optimal settings of the adaptive filters based on maternal surface ECG electrode placements. The experimental results further confirmed the theoretical assumption that the optimal settings of these adaptive filters are dependent on the ECG electrode positions on the maternal body, and therefore, we were able to achieve far better results than without the use of optimization. These improvements in turn could lead to a more accurate detection of fetal hypoxia. Consequently, our approach could offer the potential to be used in clinical practice to establish recommendations for standard electrode placement and find the optimal adaptive filter settings for extracting high quality fetal ECG signals for further processing. Ultimately, diagnostic-grade fetal ECG signals would ensure the reliable detection of fetal hypoxia.Web of Science175art. no. 115

Laboratory Measurements on the Role of Fetal Cardiotocography

Import 03/11/2016Bakalárska práca s témou Laboratórna úloha merania na fetálnom kardiotokografe je rozdelená do ôsmich kapitol. Prvá kapitola je zameraná na dôvod monitorovania a postupy monitorovania. Ďalšia teoretická kapitola je zameraná na princíp monitorovania a na spôsoby, akými sa monitoruje a odlišuje nepotrebný signál. Tretia kapitola je rešerš, sú v nej popísané metódy simulovania. Na simulovanie tejto práce na kardiotokografe bol vytvorený obvod, ktorý využíva relé a je zostrojený tak, aby preklápal dve frekvencie. V obvode je pridaný prepínač na prepínanie frekvencií, ktoré môžu do relé vstupovať, dve alebo iná jedna z týchto dvoch frekvencií. Kapitola 6 a 7 obsahujú návrh a realizáciu laboratórnej úlohy. Laboratórna úloha je navrhnutá na princípe overenia správnej funkčnosti kardiotokografu a pochopenie korelácie, ktorú kardiotokograf využíva. Posledná kapitola obsahuje zhodnotenie dosiahnutých výsledkov a porovnanie medzi dvomi kardiotokografmi a to CADENCE II a BFM 800.Bachelor thesis which is named the theme of the Laboratory measurement's tasks for fetal cardiography is divided into 8 chapters. The first chapter focuses on the reason for monitoring and monitoring procedures. The another one is theoretical. It focuses on on the principle of monitoring and the ways in which monitors and distinguishes unnecessary signal. The third chapter is a search, there is described the methods of simulation. For this simulation of the work was created electrical circuit where used relay and it is constructed such that the frequency of the two flips. In the circuit there is a switch to use for switching frequency, which may be the relay output, two or one of these frequencies.The chapter 6 and 7 includes the design and implementation of laboratory projects. Laboratory project is designed on the principle of verification of the correct functioning and the understanding of correlations that uses in the Cardiotocography. T he last chapter includes an assessment of achievements and a comparison between the two cardiography - CADENCE II and BFM 800th450 - Katedra kybernetiky a biomedicínského inženýrstvívelmi dobř

Fetal PCG Signal Processing

Tato diplomová práce se zabývá extrakcí plodového fonokardiogramu (fFKG) ze záznamů pořízených na abdominální oblasti matky neinvazivním senzorem pomocí navrženého softwarového řešení. Abdominální fonokardiogram (aFKG) se skládá ze směsi fFKG, mateřského (mFKG) a šumu ve formě pohybů matky a plodu, zvuků z orgánů a vnějších zvuků. V práci je nejprve popsána teorie o vývoji plodu a jeho srdci. Poté je v práci popsána rešerše zabývající se všemi metodami, pomocí kterých lze extrahovat fFKG a poté jsou popsány algoritmy vybraných metod. Navržený systém se zakládá na FIR filtraci a vlnkové transformaci (WT) a primárně je zaměřen na stanovení plodové tepové frekvence (fHR) a vykreslení průběhů fHR. Funkčnost tohoto softwarového systému je testována na syntetických záznamech a reálných záznamech z databází. Hodnocení kvality je provedeno stanovením fHR a odstupu signálu od šumu (SNR).This thesis deals with extraction of fetal phonocardiogram (fFKG) from the recorded signals acquired on the abdominal area of the mother with a non-invasive sensor using the proposed software solution. The abdominal phonocardiogram (aFKG) consists of a mixture of fFKG, maternal (mFKG) and noise in the form of mother and fetal movements, organ sounds and external sounds. The thesis describes first the theory of the development of the fetus and its heart. Then, the research describes all the methods by which fFKG can be extracted and algorithms of the selected methods are described. The proposed system is based on FIR filtering and wavelet transformation (WT) and primarily focuses on determining fetal heart rate (fHR) and plotting the fHR waveforms. Functionality of this software system is tested on synthetic records and real records from databases. Quality assessment is performed by determining fHR and SNR.450 - Katedra kybernetiky a biomedicínského inženýrstvívýborn