A Periodic Extension Approach for HHT Empirical Mode Decomposition
Na Zhao · Jisuanji fangzhen · 2008
To overcome the boundary effect of empirical mode decomposition, the truncation error of cubic spline interpolation in the endpoint neighborhood is described by using the theory of interpolation.The causation of the boundary effect is analysed. The periodic extension approach is developed in this work. To guarantee the smoothness of the periodically extended signal, both the symmetric and anti-symmetric extensions are proposed. The former, also referred to as mirror extension, can be applied to the case when the signal reaches its extreme at the ends, while the latter is designed for the case where the signal takes zero values. The truncation error and the success of applying both extensions to some typical simulating signals and speech data demonstrate the validity and feasibility of this method, and hence greatly improving the precision and reliability of the decomposition.