结合QRS检测和小波阈值的膈肌肌电信号降噪方法

EMGdi Denoising Combining QRS Detection and Wavelet Threshold

为了消去夹杂在膈肌肌电(EMGdi)信号中的心电干扰,在比例阈值算法的基础上,提出一种结合QRS检测和小波阈值的降噪方法。首先,根据小波系数的相关性构造QRS波群的检测方法,分析确定干扰的位置和范围;其次,将小波系数分为受干扰和未受干扰两部分,并构造相应的阈值算法,针对性地处理受干扰系数,以未受干扰部分系数作为阈值算法构造的依据;最后,重构处理后的小波系数,得到降噪后的EMGdi信号。对临床采集信号的处理对比表明,该方法能够更为有效地去除心电干扰,并更好地保留EMGdi的有用信号。

In order to eliminate the ECG interference included in diaphragmatic electromyographic （EMGdi）, an ECG cancellation algorithm based on proportional threshold algorithm was presented in this paper. The algorithm combined QRS detection and wavelet threshold. Firstly, a QRS detection was made by the correlation of wavelet coefficients. Secondly, the wavelet coefficients were divided into noised and clean part. The former was processed by improved threshold algorithm, while the latter was used to construct the threshold. Lastly, the denoised signals were reconstructed by wavelet coefficients. The result of clinical signals processing showed that the proposed algorithm eliminated the ECG interference in EMGdi availably and reserved EMGdi useful signal effectively as well.