王文波　钱龙

摘   要：针对母体腹部混合心电信号中胎儿心电信号微弱、包含诸多噪声，难以清晰提取的问题，本文提出了一种基于奇异值分解（SVD）、平滑窗（SW）技术和最小二乘支持向量机（LSSVM）的胎儿心电提取新方法. 首先，利用SVD从单通道母体腹部心电信号中重构分解矩阵，估计出母体心电参考信号，并利用SW方法对估计出的母体心电参考信号进行平滑处理;然后，利用LSSVM建立非线性估计模型，通过该模型和平滑后的母体心电参考信号估计出腹部信号中的母体心电成分，并采用布谷鸟搜索算法（CS）优化LSSVM的超参数;最后，将腹部混合信号与CS-LSSVM模型估计出的母体心电成分相减，即可获得初步胎儿心电信号，为了进一步消除干扰，对初步获取的胎儿心电信号再进行SW-SVD操作，从而获得较为清晰的胎儿心电信号. 采用Daisy数据集进行实验，结果表明，本文所提出的方法在可视化对比分析和四个统计评价指标上均优于其他三种经典方法，可从腹部混合信号中提取出更清晰的胎儿心电信号.

關键词：胎儿心电信号;奇异值分解;平滑窗;最小二乘支持向量机;布谷鸟搜索算法

中图分类号：R331                              文献标志码：A

A New Technology for Extracting Fetal ECG Signals

from Single-channel Maternal Abdominal ECG Signals

WANG Wenbo QIAN long

（College of Science，Wuhan University of Science and Technology，Wuhan 430065，China）

Abstract：Aiming at the problems that the fetal electrocareliogram（ECG） signal in the mixed ECG signal of the mother's abdomen is weak，contains a lot of noise，and is difficult to be extracted clearly，this paper proposes a method based on singular value decomposition （SVD），smooth window （SW） technology and least square support vector machine （LSSVM） new method of fetal ECG extraction. Firstly，SVD is used to reconstruct the decomposition matrix from the single-channel maternal abdominal ECG signal in order to estimate the maternal ECG reference signal，and the SW method is used to smooth the estimated maternal ECG reference signal;then，LSSVM is used to establish a non-linear estimation model，the maternal ECG component in the abdominal signal is estimated through the model and the smoothed maternal ECG reference signal，and the cuckoo search algorithm（CS） is used to optimize the hyperparameters of LSSVM. Finally，the mixed abdominal signal is subtracted from the maternal ECG component estimated by the CS-LSSVM model so as to obtain the preliminary fetal ECG signal. To further eliminate the interference，the SW-SVD operation is performed on the initially obtained fetal ECG signal，thereby obtaining a clearer fetal ECG signal. Experiments with Daisy data set show that the method proposed in this paper is superior to the other three classic methods in visual comparative analysis and four statistical evaluation indicators，and can extract clearer fetal ECG signals from the mixed abdominal signals.

Key words：fetal ECG signal;singular value decomposition;smooth window;least squares support vector machine;cuckoo search algorithm

据统计，全世界每年发生260多万例死产，其中45%以上病例发生于孕妇分娩期间，因此产前胎儿健康检测具有重要的生理学意义[1]. 通过在孕妇分娩前对胎儿心电信号进行检测，并分析其波形，可以高效评估胎儿在子宫内的生长发育情况，从而降低围产儿的死亡率和……