Yamakoshi Y, Otaki H, Shinozuka N, Masuda H
Faculty of Engineering, Gunma University, Japan.
Ultrasonics. 1996 Dec;34(8):769-75. doi: 10.1016/s0041-624x(96)00080-7.
We have developed a fetal movement monitoring system based on small displacement measurement of internal tissues. When ultrasonic pulses are transmitted to the fetus, the reflected ultrasonic waves which have a Doppler frequency shift due to the fetal movements are detected by using an ultrasonic pulsed Doppler technique. In this paper, we propose a displacement measurement method for internal tissues which is based on the Doppler signal digital detection technique. In the method, the received ultrasonic RF signals are sampled with a sampling frequency of four times higher than the centre frequency of the ultrasonic waves; the Doppler frequency shift signals are derived using digital signal processing. From the detected signals, the internal displacements are estimated using the arc-tangent method. The basic algorithm of the detection method has already been used in the area of blood flow sensing, however, we apply the algorithm to the displacement measurement of internal tissues. The comparison between the proposed method and the conventional method is presented. The fetal movement quantitative monitoring system based on the method which has been constructed is shown.
我们基于内部组织的小位移测量开发了一种胎儿运动监测系统。当超声脉冲发射到胎儿时，利用超声脉冲多普勒技术检测因胎儿运动而产生多普勒频移的反射超声波。在本文中，我们提出了一种基于多普勒信号数字检测技术的内部组织位移测量方法。该方法中，以高于超声波中心频率四倍的采样频率对接收的超声射频信号进行采样；利用数字信号处理得出多普勒频移信号。根据检测到的信号，采用反正切方法估计内部位移。该检测方法的基本算法已在血流传感领域得到应用，然而，我们将该算法应用于内部组织的位移测量。给出了所提方法与传统方法的比较。展示了基于已构建方法的胎儿运动定量监测系统。
