中文摘要：

为了有效的从超声多普勒胎儿心脏回波信号中提取胎心率,分析了多普勒回波信号的特点,通过空域相关法估计了原始噪声方差,提出了一种自适应去噪阈值计算方法,该算法能根据实际信号的强度、噪声的方差以及分解的层数,自适应的得到不同尺度的去噪阈值。最后通过对实际超声多普勒回波信号的处理,能有效地降低噪声,提取出胎儿心音信号,较准确地计算出胎儿心率值。

英文摘要：

To extract heart rate effectively from the Doppler fetus heart signals, the characteristics of Doppler echo signal was analyzed. Through the spatial correlation estimated original noise variance, an adaptive method was proposed that calculated de-noising threshold for different scales based on actual signal intensity, the noise variance and the number of decomposition layers. Through processing actual Doppler fetal heart sound signal, the method could effectively reduce the noise and extract fetal heart sounds, and more accurately calculate fetal heart rate.