基于形态分量分析的保幅面波压制方法

Amplitude-preserved ground-roll suppression method based on morphological component analysis

根据近年来发展起来的稀疏信号理论及有效反射波与面波的形态特征不同,将含面波炮记录单道化,采用形态分量分析(MCA)方法分离面波。MCA方法的核心是选取适当的字典,从有效反射波与面波的形态差异出发,选取一维非抽样离散小波波变换(UDWT)字典和局部离散余弦变换(LDCT)字典,一维UDWT字典用来稀疏表示面波部分,一维LDCT字典用来稀疏表示有效反射波部分。采用块协调松弛算法(BCR)求解目标函数,将单道化的含面波单炮记录分为有效反射波部分和面波部分,进而达到去除面波的目的。实际资料处理表明,利用本文MCA方法能够有效压制面波,同时能较好地保护有效反射波(特别是反射波的低频、低波数成分),是一种保幅的面波压制方法。

According to the recently developed sparse signal theory and the morphological differences between reflections and ground-roll,the shot gather which contains ground-roll is reshaped to be a one-dimensional array,and the morphological component analysis(MCA) technique is used to separate the ground-roll.The key of the MCA method is to choose the appropriate dictionaries.In view of the morphological differences between reflections and ground-roll,two kinds of dictionaries are chosen.They are the one-dimensional UDWT dictionary and the one-dimensional LDCT dictionary.The first one represents sparsely the ground-roll component in common-shot records,and the second one represents sparsely the reflections in common-shot records.Block-coordinate relaxation(BCR) algorithm is used to calculate the objective function,and the shot record is decomposed into ground-roll component and reflection component.Then the ground-roll is removed.Real data examples show that the MCA method not only can successfully remove ground-roll,but also preserve reflections,especially for low frequency and low wave-number information.