| Summary: | 碩士 === 中原大學 === 生物醫學工程研究所 === 103 === The fetal electrocardiogram (FECG) is one of the reference index for monitoring the fetal heart physiological activity. It is very important to predict the health of fetus during pregnancy. Therefore, it is necessary to evaluate the growth and development of fetal through the measurement of FECG signal. By measuring signals from the abdomen of pregnant women is convenient and secure. However, the fetal signal is relatively small and contains more noise. To capture a clean FECG signal, the unwanted noise must be removed.
This study developed a electrode system that is similar to a enlarged Laplace electrode to acquire FECG signal. The Laplace electrodes made of conductive fabric, and placed on a maternity belt as the front-end electrode to detect abdomen signals. The enlarged Laplace electrode can cover large abdominal area. Thus, it is possible to reduce the impact caused by the position of fetal and electrode placement. The TMS320C5515 fixed-point digital signal processor from the Texas Instrumentation was used to control the ADS1294, using serial peripheral interface (SPI). The ADS1294 can reduce the front end electronic circuit used by multi-lead ECG acquisition system. The acquired signal is fetched into the digital signal processor to perform the signal processing algorithm and determine the fetal heart rate. Finally, results are transmitted through the Bluetooth low energy in order to observe the fetal heart rate trends.
This study uses the PhysioNet challenge 2013 set A database to validate the proposed signal processing algorithm. Twenty signal set was selected for testing, and the accuracy is 75.48%. However, the quality of acquired signal will affect the averaged accuracy significantly.
This study also uses the proposed system on pregnant women. The results indicate that this system can acquire abdomen signals successfully. By comparing the detected FECG R wave positions and the fetal R wave positions marked by experts, the averaged accuracy of fetal QRS detection was 69.3%.
In conclusion, the study constructs a Laplace electrode system for fetal monitoring. The proposed signal processing algorithm can successfully separates the maternal and fetal ECG, detects the fetal QRS, and computes the fetal heart rate.
|
|---|
