The Design And Implement Of The Improved Fetal Heartbeat Rate Monitor Algorithm Based On The Ultrasonic Doppler

The fetal heart beat rate is the important information which reflects the fetal health state. If the fetal heart beat rate is too low or too high, then the heart beat rate is abnormal. The heart rate abnormity is usually caused by the oxygen loss and blood loss and these symptoms can lead the birth disfigurement. And until now, the birth disfigurement has been the horrible problem for the population quality. So the fetal heart beat rate monitor is very meaning for improving the birth quality. For the conventional fetal heart beat rate monitor, the pregnant women must be in the hospital and the price is too high. But now, the fetal heart beat rate with the ultrasonic Doppler appears while the electronic technology improves. This instrument is small and the price is low, so it is adapt to be used for the family. But now this monitor still has a lot of disadvantages, which is caused by the heart rate detection algorithm. In this paper, a new detection algorithm is proposed in order to improve the precision of the heart rate detection.First, the background of the research and the history of the fetal heart beat rate monitor is introduced, then the theory of the monitor is explained. The original heart beat rate collected with the ultrasonic Doppler is corrupted by a lot of noise and the noise affect the obtain of the right detection result. The Teager energy operator is used to restrain the noisy energy and stress the energy of the useful signal. And then the all phase DFT filter is used for extracting the envelope of the heart beat signal. In this paper, the theory of the all phase filter is introduced in detail and compared with the frequency sampling method. The comparing result shows that the all phase DFT filter is better than the frequency sampling method in the aspect of the bandwidth of the transition and the control of the frequency response. Additionally, we introduce the realization of the program using the Visual C++ and give the results of the program.At last, we summarize the experiment results and point the disadvantage and the next research direction. Above all, there are three points in this paper:1. A improved autocorrelation monitoring algorithm is proposed based on the Teager energy and all phase filter.2. The algorithm is simulated with the matlab.3. The algorithm is realized by the Visual C++ 6.0.