心电信号的小波变换消噪方法

Noise rejection method of wavelets for ECG signal

人体心电信号微弱,信噪比较低.为了消除心电信号中的噪声,提高心电监护仪的性能和计算机自动诊断效率,人们已提出了多种方法来消除这些噪声.小波变换是一种信号的时间尺度(即时间频率)分析方法,具有多分辨率分析的特点。它对信号具有的自适应性,使其成为数字信号处理领域中的一个重要工具.这里提出了一种采用阈值预处理的小波变换消噪方法,该方法可以降低模极大值消噪算法计算的复杂程度,又可保证心电信息特征不被丢失.试验表明,该方法能较好地实现心电信号的消噪.显然,该方法也适合于信噪比较低的生物信号的处理中.

The ECG(electrocardiogram)signal is one of mini-voltage.The ratio of signal-noise is lower.In order to eliminate the noise in ECG,improve the performance of ECG monitors and increase the diagnosis efficiency of computer-aided systems,various kinds of noise rejection methods have been proposed.Wavelet transform is a kind of analytical tool in time-scale(i.e.time-frequency)domain.It has the feature of multi-resolution analysis.The adaptation characteristic of the wavelet has made it become an important tool in signal processing.A noise rejection method of wavelets with pre-threshold was proposed here.The proposed method not only simplifies the complexity of calculation in the noise rejection method with maximum norm,but also preserves the characteristics of ECG.Experiments show that the proposed method eliminates the noise effectively.The proposed method could also apply to the biomedical signal processing with lower ratio of signal-noise.