目的 提高心电自动诊断中,心电(electrocardiogram,ECG)信号特征波定位的准确度.方法 在多尺度数学形态学导数(multi-scale morphological derivative,MMD)的基础上提出双层尺度数学形态学导数(double-layer scales morphological derivative,DSMD)的概念,并结合局域变换法对心电信号特征波进行检测.首先,在对心电信号进行大尺度DSMD变换基础上定位R、P、T波波峰位置,然后,在R、P、T波波峰位置确定的前提下,重新选择尺度,在ECG信号的小尺度DSMD变换上准确定位R波、P波和T波边界点,最后,在R波边界点确定的前提下运用局域变换法检测Q、S波,并最终确定QRS波边界点.结果 DSMD算法结合局域变换法对ECG特征波的提取效果良好.结论 本文提出的DSMD在尺度选择上更具灵活性,相比于MMD算法显著提高了检测精度,并且达到量化心电图通用标准(common standards for quantitative electrocardiography,CSE).%Objective To improve the detection accuracy of characteristic waves in electrocardiogram ( ECG ). Methods Based on multi-scale morphological derivative ( MMD ),a new modified method,double-layer scales morphological derivative ( DSMD ) combined with local feature conversion, is presented to detect ECG characteristic wave in this paper. First,DSMD is applied to ECG signal to position R,P,T peaks. Then,on the premise that R,P,T peaks are positioned,the boundaries of R,P,T peaks are accurately positioned on DSMD in a smaller scales than those used in the first step. Finally, the local feature conversion is used to detect whether Q and S waves exist, and eventually determine the boundaries of QRS complex. Results The detection effect of ECG characteristic wave is good by using DSMD algorithm combined with local feature conversion. Conclusions Compared with MMD algorithm,the proposed algorithm is more flexible in the choice of scales,greatly declines the detection error and meets the common standards for quantitative electrocardiography( CSE ).
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