【摘要】 在面波压制方法中,常规面波消除方法都是单一的利用面波某种特性,如Fourier变换域方法利用波组的频率差异等,难以有效地压制面波,并且根据单一的波组特征差异进行面波消除很容易损伤有效波信息。Curvelet变换可以对时空信号进行最稀疏表达,能够获得最优的非线性逼近。分析地震信号面波与有效反射波在Curvelet域(j,θ,k)三维空间的特征差异,将空间域波组方向与Curvelet域角度变量联系起来,指出可以在Curvelet域利用波组的频率、角度和空间位置差异实现波场分离,并设计非线性阈值函数对面波系数进行衰减,避免传统软、硬阈值函数的不足。研究结果表明:基于Curvelet域的面波压制方法受随机噪声的影响较小,它可以有效地压制面波干扰,同时对有效波信息的保真度高。更多还原

【Abstract】 The traditional methods can suppressing the surface wave to some extent,but they only use single characteristic.For instance,Fourier transform methods use the frequency characteristic between surface wave and effective wave.When these methods are employed to attenuate surface wave,the signal components may be harmed.Curvelet transform is characterized by optimum sparseness constraint condition that it can deal with line-like phenomena in high dimension.The signal characteristic in(j,θ,k) of Curvelet domain between surface wave and desirable signal was analyzed,and the Curvelet angle was linked with the direction of wave group,so surface wave will be separated from effective wave based on the differences in frequency,angle and position characteristics.And besides,a non-linear thresholding was designed to suppress the surface wave coefficients which can avoid the discontinuity caused by the hard or soft thresholding.The results show its feasibility and effectiveness in attenuating surface wave,and it can provide superior surface wave attenuation with minimal impact on the desirable signal components.更多还原