一种削弱信噪混叠的EMD降噪方法

An EMD Noise Reduction Method for Reducing Signal Noise Aliasing

针对经验模态分解(empirical mode decomposition,EMD)降噪过程中存在信号与噪声模态混叠及直接将分界本征模态函数(intrinsic mode function,IMF)分量归入高频噪声造成真实信号被“湮没”等问题,提出一种改进的EMD降噪方法。该方法将经EMD得到的第2个IMF分量至分界IMF分量进行重构,对重构信号进行下一次EMD,获取其中的“真实”信号,多次重复此操作,最后将所有获得的低频信号累加,从而达到降噪的目的。利用2种模拟数据和1种GPS实测高程数据进行实验,模拟数据与实测数据采用不同的评价指标评价降噪效果,结果表明,改进的EMD方法较传统EMD方法降噪效果更佳,验证了该方法的可靠性。

For the empirical mode decomposition(EMD)noise reduction process,there is signal and noise mode aliasing,and the intrinsic mode function(IMF)component is directly classified into high frequency noiseto generate real signals.The real signal is“submerged,”among other issues.This paper proposes an improved method of EMD noise reduction.The improved EMD denoising method mainly reconstructs the second IMF to demarcate the IMF component obtained by EMD decomposition,performs the next EMD decomposition on the reconstructed signal,obtains the“real”signal therein,and repeats this operation multiple times.Finally,all the obtained low frequency signals are accumulated to achieve the purpose of noise reduction.Experiments are carried out using three kinds of simulation data and one kind of GPS measured elevation data.The simulation data and the measured data are evaluated by different evaluation indexes.The results show that the improved EMD method has better noise reduction effects than the traditional EMD method,and the reliability of the method is verified.