• Title/Summary/Keyword: Fetal heart rate

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Fetal heart rate estimation algorithm for real-time processing (실시간처리를 위한 태아심음 추출 알고리듬)

  • Lee, Eung-Gu;Lee, Yong-Hui;Kim, Seon-Il;Lee, Du-Su
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.05
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    • pp.96-99
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    • 1994
  • Despite the simplicity of processing, a conventional autocorrelation function(ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In case of weak or noise corrupted Doppler ultrasound signal. the ACF method is very sensitive to the threshold level and data window length. It is very troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm was adopted to estimate the FHR. This method is more accurate, robust and reliable than the ACF method. With a lot of calculation, however, it is impossible to process real time FHR estimation. This paper is presented a new FHR estimation algorithm for real time processing.

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Fetal heart rate estimation using high resolution pitch detection algorithm (피치 검출 방법을 이용한 태아심음주기의 추출에 관한 연구)

  • Lee, Eung-Goo;Lee, Yong-Hee;Kim, Sun-I.;Lee, Doo-Soo
    • Proceedings of the KOSOMBE Conference
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    • v.1993 no.05
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    • pp.81-85
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    • 1993
  • Despite the simplicity of processing, conventional autocorrelation function (ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In the case of weak or noise corrupted Doppler ultrasound singnals, the ACF method is very sensitive to the threshold level and data window length. It is real troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm is adapted to estimate the FHR. The FHR is determined from the correlation of two interconnected segments by its maximum correlation value. FHR is compensated with a constant correlation threshold in a greatly smeared noise signal. This method yields more accurate, robust and reliable than the ACF method.

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A Study on the Separation of Fetal ECG from a Single Channel Abdominal ECG (단일채널 복부 심전도를 통한 태아 심전도 분리)

  • Park Kwang-Li;Lee Kyoung-Joung;Lee Jeon
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.3
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    • pp.198-205
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    • 2005
  • In this paper, we proposed a new algorithm for the separation of fetal ECG from single channel abdominal ECG. The algorithm consists of a stage of demixing vector calculation for initial signal and a stage of fetal beat detection for the rest of signal. The demixing vector was obtained by applying independent component analysis technique to projected signals into time-frequency domain. For the test of this algorithm, simulation signals, De Lathauwer's data and some measured data, which was acquired from 8 healthy volunteers whose pregnant periods ranged from 22 weeks to 35 weeks and whose ages from 27 to 37, were used. For each data, the accuracy of fetal beat detection was $100\%$ and with the location of fetal beats, fetal heart rate variability and morphology could be offered. In conclusion, this proposed algorithm showed the possibility of fetal beat separation with a single channel abdominal ECG and it might be adopted to a fetal health monitoring system, by which a single channel abdominal ECG is acquired.

Development of Time Varying Kalman Smoother for Extracting Fetal ECG using Independent Component Analysis : Preliminary Study (독립요소분석을 이용한 태아심전도 추출을 위한 시변 칼만 평활기의 개발 : 예비연구)

  • Lee, Chung Keun;Kim, Bong Soo;Kwon, Ja Young;Choi, Young Deuk;Song, Kwang Soup;Nam, Ki Chang
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.202-208
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    • 2012
  • Fetal heart rate monitoring is important information to assess fetal well-being. Non-invasive fetal ECG (electrocardiography) can be derived from maternal abdominal signal. And various promising signal processing methods have been introduced to extract fetal ECG from mother's composite abdominal signal. However, non-invasive fetal ECG monitoring still has not been widely used in clinical practice due to insufficient reliable measurement and difficulty of signal processing. In application of signal processing method to extract fetal ECG, it might be lower signal to noise ratio due to time varying white Gaussian noise. In this paper, time varying Kalman smoother is proposed to remove white noise in fetal ECG and its feasibility is confirmed. Wiener process was set as Kalman system model and covariance matrix was modified according to white Gaussian noise level. Modified error covariance matrix changed Kalman gain and degree of smoothness. Optimal covariance matrix according to various amplitude in Gaussian white noise was extracted by 5 channel fetal ECG model, and feasibility of proposed method could be confirmed.

Effect of Highly Concentrated Oxygen and Stimulus of Odors on the Performance of Secondary Tasks While Driving Using Vehicle Graphic Driving Simulator (자동차 화상시뮬레이터에서 운전 중 동시과제 수행에 고농도 산소와 향 자극이 미치는 영향)

  • Ji, Doo-Hwan;Min, Cheol-Kee;Ryu, Tae-Beum;Shin, Moon-Soo;Chung, Soon-Cheol;Kang, Jin-Kyu;Min, Byung-Chan
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.35 no.4
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    • pp.55-62
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    • 2012
  • In this study, it was observed through the ability of performing secondary tasks and baseline fetal heart rate how the supply of lavender, peppermint and highly concentrated oxygen (40%) affected distraction due to the performance of secondary tasks in the driving environment. Twelve male university students conducted secondary tasks while driving in the environments (6 in total) mixed and designed with oxygen concentration (21%, 40%) and the condition of odors (Normal, Lavender, Peppermint). The test was proceeded in order of stable state (5mins), driving (5mins), and secondary tasks (1min), and by extracting ECG data from every section by 30secs, the mean value of baseline fetal heart rate was calculated. As a result of analysis, in the ability of performing secondary tasks, a percentage of correct answers showed no difference in oxygen concentration and the condition of odors (p > 0.05). In performance completion time, a percentage of correct answers decreased showing a statistically significant difference in the condition of odors compared with the condition where odors were not provided (p < 0.05). As for baseline fetal heart rate, in the comparison between sections, while performing secondary tasks, it increased showing a significant difference compared with stable state and driving state (p < 0.05). The effect of interaction was observed in oxygen concentration and the condition of odors. When odors were not provided, baseline fetal heart rate decreased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05), however, when peppermint was provided, it increased in 40% oxygen concentration compared with 21% oxygen concentration (p < 0.05). In conclusion, the fact that the condition of odors increased the ability of calculation, and when only the highly concentrated oxygen was provided, parasympathetic nerve system was activated, however, when highly concentrated oxygen was provided with peppermint at the same time, sympathetic nervous system (sns) was activated, which had a negative effect on the autonomic nervous system was drawn.

A study on the nonlinearity in bio-logical systems using approximate entropy and correlation dimension (근사엔트로피와 상관차원을 이용한 비선형 신호의 분석)

  • Lee, Hae-Jin;Choi, Won-Young;Cha, Kyung-Joon;Park, Moon-Il;Oh, Jae-Eung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.760-763
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    • 2007
  • We studied how linear and nonlinear heart rate dynamics differ between normal fetuses and uncomplicated small-forgestational age (SGA) fetuses, aged 32-40 weeks' gestation. We analyzed each fetal heart rate time series for 20 min and quantified the complexity (nonlinear dynamics) of each fetal heart rate (FHR) time series by approximate entropy (ApEn) and correlation dimension (CD). The linear dynamics were analyzed by canonical correlation analysis (CCA). The ApEn and CD of the uncomplicated SGA fetuses were significantly lower than that of the normal fetuses in all three gestational periods (32-34, 35-37, 38-40 weeks). Canonical correlation ensemble in SGA fetuses is slightly higher than normal ones in all three gestational periods, especially at 35-37 weeks. Irregularity and complexity of the heart rate dynamics of SGA fetuses are lower than that of normal ones. Also, canonical ensemble in SGA fetuses is higher than in normal ones, suggesting that the FHR control system has multiple complex interactions. Along with the clear difference between the two groups' non-linear chaotic dynamics in FHR patterns, we clarified the hidden subtle differences in linearity (e.g. canonical ensemble). The decrease in non-linear dynamics may contribute to the increase in linear dynamics. The present statistical methodology can be readily and routinely utilized in Obstetrics and Gynecologic fields.

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Development of Diagnostic System for FHR Monitering by Using Neural Networks

  • Cha Kyung-Joon;Park Moon-Il;Oh Jae-Eung;Han Hyun-Ju;Lee Hae-Jin;Park Young-Sun
    • Communications for Statistical Applications and Methods
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    • v.13 no.1
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    • pp.73-88
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    • 2006
  • In this paper, we construct data-base for fetal heart rate (FHR) data and develop the FHR Monitering system to diagnose fetus, HYFM-III. For diagnostic system, a few statistical decision making mechanism are adopted, such as approximate entropy, neural networks, and logistic discrimination. Since FHR data is very chaotic, we mostly adopt nonlinear statistical methods. On the basis of this system, we expect to develop expert system for early detection of abnormal fetus.

A study on the real time fetal heart rate monitoring system by high resolution pitch detection algorithm (고해상 피치 검출 알고리듬을 적용한 실시간 태아 심음 감시시스템에 관한 연구)

  • 이응구;이두수
    • Journal of Biomedical Engineering Research
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    • v.16 no.2
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    • pp.175-182
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    • 1995
  • Despite the simplicity of processing, a conventional autocorrelation function (ACF) method for the precise determination of fetal heart rate (FHR) has many problems. In case of weak or noise corrupted Doppler ultrasound signal, the ACF method is very sensitive to the threshold level and data window length. It is very troublesome to extract FHR when there is a data loss. To overcome these problems, the high resolution pitch detection algorithm was adopted to estimate the FHR. This method is more accurate, robust and reliable than the ACF method. With a lot of calculation, however, it is impossible to process real time FHR estimation. This paper is presented a new FHR estimation algorithm for real time processing and studied the real time FHR monitoring system by high resolution pitch detection algorithm.

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Classification of cardiotocograms using random forest classifier and selection of important features from cardiotocogram signal

  • Arif, Muhammad
    • Biomaterials and Biomechanics in Bioengineering
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    • v.2 no.3
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    • pp.173-183
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    • 2015
  • In obstetrics, cardiotocography is a procedure to record the fetal heartbeat and the uterine contractions usually during the last trimester of pregnancy. It helps to monitor patterns associated with the fetal activity and to detect the pathologies. In this paper, random forest classifier is used to classify normal, suspicious and pathological patterns based on the features extracted from the cardiotocograms. The results showed that random forest classifier can detect these classes successfully with overall classification accuracy of 93.6%. Moreover, important features are identified to reduce the feature space. It is found that using seven important features, similar classification accuracy can be achieved by random forest classifier (93.3%).

The Development of Digital FHR Monitoring System Using PC and DSP (PC와 디지탈 신호 처리기를 이용한 디지탈 FHR 감시 장치의 개발)

  • Chung, Ji-H.;Kim, Sun-I.;Park, Moon-I.;Lee, Doo-S.
    • Proceedings of the KOSOMBE Conference
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    • v.1991 no.11
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    • pp.79-82
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    • 1991
  • Digital FHR monitoring system based on the personal computer combined wi th the digital signal processing (DSP) board was implemented. The DSP board acquires and digitally processes ultrasound fetal Doppler signal for digital rectification, envelope detection, autocorrealtion function calculation and its peak position detection. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data taransmission and on-line analysis of fetal heart rate change including on-line warning system, base-line estmation, acceleration, deceleration and variability. The advantages of PC-DSP based system can be summarized as follows: 1) Minimum hardware realization. 2) Increased flexibility. 3) Total care system.

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