- 學位論文
實現拉普拉斯胎兒心電圖監測系統
REALIZATION OF LAPLACIAN FETAL ELECTROCARDIOGRAM MONITORING SYSTEM
摘要
胎兒心電圖可以用來預測胎兒的健康狀況，因此懷孕期間量測胎兒心 電圖是非常重要的。雖然使用非侵入式的方式量測孕婦腹部心電訊號較為 方便，但因為胎兒的訊號較小且雜訊也比較多，在訊號處理上則比較困難。 本研究以拉普拉斯電極擷取胎兒心電訊號，此電極為導電織布所製成。 此拉普拉斯電極所涵蓋的腹部面積較大，因此能夠減少由於胎位以及電極 擺放位置所造成的影響。本研究利用德州儀器所出產的 TMS320C5515 數位 處理器透過串列傳輸的方式控制 ADS1294 晶片以擷取腹部訊號，再將擷取 的訊號透過數位處理器進行演算並獲得母親及胎兒心率，最後透過 TMS320C5515 eZdsp 上的 LCD 顯示母親及胎兒心率。 在演算法部分，首先根據輸入訊號的品質決定所要進行的分析，若評 估訊號中有胎兒訊號則進行胎兒與母親的心率計算，若無明顯的胎兒訊號 則只進行母親心率的計算。 本研究將系統實際應用在孕婦上，結果顯示，本電極系統可以成功的 採集母親腹部訊號。經由與專家實際標記的母親及胎兒R波位置進行對比， 以每三秒的平均心率進行統計比較，母親及胎兒心率平均準確率分別為 92.5%及 80.3%。
並列摘要
The fetal electrocardiogram (FECG) can be used to evaluate the growth and development of fetal. Thus, it is very important to measure the FECG during pregnancy. Although, using non-invasive method to acquire signals from the abdomen of pregnant women is convenient. However, the fetal signal is relatively small and contains more noises. Additionally, it is more difficult to process the signal. This study developed an electrode system using Laplacian electrode to acquire the FECG signal. This electrode is made from conductive fabric. This enlarged Laplacian electrode can cover larger abdominal area. Thus, it is possible to reduce impacts caused by the position of fetal and the electrode placement. In this study, a TMS320C5515 eZdsp digital signal processor from Texas Instrumentation was used to control the analog frontend ADS1294, using the serial peripheral interface (SPI). The acquired signal is fetched into the digital signal processor to perform the signal processing algorithm in order to determine maternal and fetal heart rates. Finally, derived heart rates are displayed on the LCD of TMS320C5515 eZdsp. In the signal processing algorithm, first, the system determines the desired analysis according to the quality of acquired signal. If there are fetal component within the incoming signal, the maternal and fetal heart rates will be calculated. On the other hand, if there is no visible fetal signal, only the maternal heart rate will be determined. This study uses the proposed system on pregnant women. The results indicate that this system can acquire abdomen signals successfully. By comparing the maternal and fetal R wave positions determined by the system with those marked by experts, statistics analysis were performed every three III seconds. The averaged accuracies of maternal and fetal heart rate are 92.5% and 80.3%, respectively.