Abstract: To overcome the problem of end effects in the traditional empirical mode decomposition (EMD) algorithms, a two-stage EMD, named as TM-EMD, was proposed for the analysis of pulse signal. The TM-EMD used the methods of template matching and mirror extension and suited for the analysis of physiological signals, such as pulse signal, which have the inherent periodic characteristics. Firstly, the feature information (starting point, maximum point) of pulse signal were identified by TM-EMD,and the pulse signal was separated into different single cardiac cycles. Then the pulse template was generated using the signal coherent averaging technique. The beginning and the ending of pulse signal were extended into one whole cardiac cycle based on the pulse template. Finally, the mirror extension method was used to realize the process of EMD algorithm. Simulation results proved that the TM-EMD algorithm could better describe the trend of endpoints, and so could effectively restrain the end effects of the traditional EMD.

Key words: empirical mode decomposition, template matching, mirror extension, end effect