Title

The analysis and improvement on time-frequency filtering in S-transform domain

单位

(1.中国石油大学(华东)地球科学与技术学院,山东青岛266580;2.中国石油天然气集团公司东方地球物理公司博士后科研工作站,河北涿州072751)

Organization

(1.School of Geosciences,China University of Petroleum,Qingdao 266580,China;2.Post-Doctoral Scientific Research Station,BGP,CNPC,Zhuozhou 072751,China)

摘要

S变换能够提供局域化的时频谱,给信号的时变滤波提供了条件,但S变换基函数具有一定的时频局部支撑,导致传统的S域滤波会产生虚假信号和处理噪声。为此,提出了一种改进的S域滤波方法,将滤波器的时间变量与信号的时间变量严格对应,提高了滤波处理的时频局域性。将该方法应用于模拟数据和实际资料的面波压制,验证了改进方法的正确性和有效性。研究结果表明,改进的S域滤波方法可以很好地解决滤波边界处的能量泄露问题,在保真性方面明显优于传统的S域滤波方法。

Abstract

The S transform can provide localized time-frequency spectra,which offers the possibility of time-varying filtering.The disadvantage of local time-frequency support from the basis function of S transform caused the problem of the spurious signals and noise after filtering in S domain.Therefore,we proposed an improved time-frequency filtering method in S-transform domain,which improved time-frequency localization property,by strict matching time variable of filter with the counterpart of signal.Both the tests with synthetic and actual data from surface wave attenuation prove the correctness and validity of the improved method.The result showed the energy leakage problem at the boundary of the filter was solved and the fidelity of the improved method was much better than the conventional filtering method in S-transform domain.

关键词：

S变换; 时变滤波; 局域化; 保真性; 时频分析; 面波压制;

Keywords:

S transform,; time-varying filters,; localization,; fidelity,; time-frequency analysis,; surface wave attenuation;

基金项目

国家自然科学基金项目(41374122)和国家高技术研究发展计划(863计划)课题(2011AA060301)联合资助。

DOI

10.3969/j.issn.1000-1441.2015.04.005

S域时频滤波分析与改进