Construction of least asymmetric higher density wavelet bases and its application
Jiaxu Wang · Zhendong yu chongji · 2010
The higher density discrete wavelet transformation with two generators can realize intermediate scales analysis,and is an approximate shift invariant,so that it is very suitable for signal denoising.Aiming at the bad symmetry of the current higher density wavelet bases,an approach for construction of least asymmetric higher density wavelet bases was proposed.The nearest linear-phase low-pass filter was chosen optimally from all the possible factorization results of the maximaum flat linear-phase(FIR)filter with the proposed method.Subsequently,the two wavelet filters were obtained.Then,the least asymmetric higher density wavelets could be constructed.Simulation experiments showed that using the new wavelets can improve the denoising performance of the higher density discrete wavelet transformation compared with the current wavelets.The application results in denoising a roller bearing fault vibration signal showed that the constructed wavelets can effectively extract the bearing fault characteristic from that signal.