模板优选结合非线性模板匹配多普勒胎心率提取方法

超声多普勒胎心心率测量方法是目前胎心心率计数的金标准,但现有各种胎心仪的胎心率提取算法在第二产程母体干扰较强的情况下容易发生误检。针对这一不足,本文提出了优选模板结合非线性模板匹配的方法,该方法通过聚类建立时频帧模板库,然后从模板库中选取模板对信号进行模板匹配。在对信号进行短时傅里叶变换后,逐帧对信号与模板的差进行带泄露线性整流(LReLU)函数的最优化,以优化结果作为模板匹配度。最后,对匹配度曲线进行峰值提取,获取胎心率。本研究将提出的方法与自相关法进行对比,结果显示本文方法比自相关方法的检出正确率平均提高20%,23%的样本正确率提高50%以上。本文通过分析干扰与信号发生混合时的特点设计算法,希望通过本文为胎心率提取提示一种不仅仅关注信号层面的新思路。

Optimal template selecting combined with non-liner template matching for Doppler fetal heart rate extraction

The ultrasound Doppler fetal heart rate measurement is the gold standard of fetal heart rate counting. However, the existing fetal heart rate extraction algorithms are not designed specifically to suppress the high maternal interference during the second stage of labor, and false detection occurrences are common during labor. With this background, a method combining time-frequency frame template library optimal selecting and non-linear template matching is proposed. The method contributes a template library, and the optimal template can be selected to match the signal frame. After the short-time Fourier transform of the signal, the difference between the signal and the template is optimized by leaky rectified linear unit (LReLU) function frame by frame. The heart rate was calculated from the peak of the matching curve and the heart rate was calculated. By comparing the proposed method with the autocorrelation method, the results show that the detection accuracy of the proposed method is improved by 20% on average, and the non-linear template matching of 23% samples is at least 50% higher than the autocorrelation method. This paper designs the algorithm by analyzing the characteristics of the interference and signal mixing. We hope that this paper will provide a new idea for fetal heart rate extraction which not only focuses on the original signal.