Determination of the Optimal Decomposition Layer of Wavelet De-Noising Based on Signal Band Feature

摘要

In this paper, based on the frequency distribution law of discrete wavelet de-noising, the expression of the optimal decomposition layer of wavelet de-noising is deduced. By simulating the signals of four different frequency bands, the optimal decomposition number of single frequency signal de-noising calculated by the expression has the same result as the composite evaluation index method. The acoustic emission signal of concrete cracking is a multi-frequency broadband wave. The signal optimal decomposition layer of the crack initiation phase and crack propagation stage obtained by the composite index identification method both are 5, same to the result of the expression calculated. This paper analyzed the variation law of de-noising composite evaluation index of the main frequency band of complex multi-main frequency wideband wave signal with the increase in the number of layers and proved the rationality of the parameter selection in the expression. Contrasting with the composite evaluation index method, the expression is suitable for the calculation of the simple and complex signal optimal decomposition number. It is easier and more reasonable.