Mittra A K, Choudhari N K
Manoharbhai Patel Institute of Engineering & Technology, Gondia, (MS), India.
J Med Eng Technol. 2009;33(4):296-302. doi: 10.1080/03091900802454384.
Motion of the foetal heart gives rise to vibrations and sounds that can be acquired through the surface of the maternal abdominal wall. The process is called foetal phonocardiography (fPCG) and its study has shown to be a very useful mechanism to evaluate the wellbeing of the unborn. These signals exhibit innate rhythms and periodicity that are more readily expressed and appreciated in terms of frequency than time units. Time-frequency distribution shows the spectral composition of signal at a particular time instant, which is also known as a spectrogram. This work investigates the analysis of foetal heart sound using time frequency distribution generated by short-time Fourier transform (STFT). An innovative method is presented for foetal heart sound acquisition, processing and coloured spectral representation, which can be used in a portable foetal home monitoring system. The outcome of the work is a numerous spectral display produced by the system for varied real and simulated foetal heart sound signals. A comparative study of normal and abnormal heart sound is presented. The spectrograms exhibit noticeable morphological differences in terms of duration and spectral composition of the sounds. The study suggests that STFT based coloured spectrograms can become an important diagnostic tool, and it is expected that the presented work will facilitate the potential use of the method in prediction of the prenatal anomalies.
胎儿心脏的运动产生振动和声音，这些振动和声音可以通过孕妇腹壁表面获取。这个过程称为胎儿心音描记术（fPCG），对其研究已表明这是评估未出生胎儿健康状况的一种非常有用的机制。这些信号呈现出固有的节律和周期性，相比于时间单位，从频率方面更容易表达和理解。时频分布显示了特定时刻信号的频谱组成，这也被称为频谱图。这项工作研究了使用短时傅里叶变换（STFT）生成的时频分布来分析胎儿心音。提出了一种用于胎儿心音采集、处理和彩色频谱表示的创新方法，该方法可用于便携式胎儿家庭监测系统。这项工作的成果是该系统为各种真实和模拟的胎儿心音信号生成的大量频谱显示。给出了正常心音与异常心音的对比研究。频谱图在声音的持续时间和频谱组成方面呈现出明显的形态差异。该研究表明基于STFT的彩色频谱图可以成为一种重要的诊断工具，并且预计所呈现的工作将促进该方法在产前异常预测中的潜在应用。
