Research Of The Fetal Heart Rate Measurement Based On Ultrasound Doppler Technique

Fetal heart rate is an important technical indicator of fetal health during pregnancy,which is closely related to the health,vitality and oxygen supply of the fetus.It can help identify problems such as fetal hypoxia and solve problems before the situation deteriorates.Monitoring of fetal heart rate is of great significance for improving pregnancy outcomes,reducing fetal morbidity and mortality,and improving the quality of birth.Due to the safety,non-invasiveness and hygiene of ultrasound Doppler,fetus-voice meter that measure fetal heart rate using the ultrasound Doppler method have been widely used.It is only necessary to transmit ultrasonic waves on the mother's abdomen through an ultrasonic probe,and the fetal heartbeat signal can be obtained by measuring the movement of the echo signal spectrum reflected by the fetal heart.However,because the fetal heart signal in the mother is hard to measure directly,a lot of data is needed to verify and improve the algorithm.In this paper,several algorithms for the acquisition of ultrasound Doppler signals and the measurement of fetal heart rate by ultrasound Doppler technique are studied.The main research work is as follows:1.This paper proposes a method for simulating ultrasonic Doppler echo signals in time-space domain.The method is based on the physical concept of wavefront propagation and the physical model of Doppler shift.It is a computationally efficient and more intuitive Doppler echo signal simulation algorithm.Compared with the existing methods,it can simulate the characteristics of real signals more realistically.And taking into account the actual conditions in each waveform cycle,the small changes in the motion state of the measured object can be quickly reacted in the Doppler shift signal in real time.The Doppler signal analysis method can be accurately verified by the simulation signal.2.This paper proposes a fetal heart rate signal simulator device based on microcontrollers.It uses a stepping motor to drive small steel balls vibrating in water to simulate the real beating of fetal heart.The TABLE UT ultrasound signal acquisition system is used to drive the ultrasonic probe to transmit ultrasound signal to detect small steel beads,and the ultrasonic echo data is collected to test some algorithms.Experiments show that the simulator can effectively simulate the fetal heartbeat and provide the required ultrasound echo data.3.Some algorithms for fetal heart rate measurement by ultrasound Doppler technology,such as autocorrelation algorithm,S-transformation,wavelet threshold denoising,etc.,are studied.An echo signal acquisition amplification detection circuit is also designed,and the ADC module is used for signal sampling and transmission to a computer for subsequent processing.In this paper,the scheme and algorithm for detecting fetal heart by pulsed ultrasou nd are explored.A simulation algorithm for acquiring fetal echo signals and a simplified fetal heart simulation device are proposed,which is simple and practical and can reduce the research and development cost.It is of great help to the development of fetus-voice meter based on ultrasonic Doppler technology.