共查询到18条相似文献，搜索用时 93 毫秒
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提出一种自适应协方差的时频域极化滤波方法。该方法在广义S变换时频方法的基础上,构造时频域自适应协方差矩阵,通过特征分析计算时频域瞬时极化参数,设计极化滤波器,实现多分量地震极化分析和滤波。其优势在于协方差矩阵的分析时窗的长度由多分量地震数据的瞬时频率确定,可以自适应于有效信号的周期,在每个时频点计算极化参数不需要进行插值处理;结合时间频率信息,解决在时间域或频率域波形或频率重叠的信号具有明显的直观性。模型数据及实际三分量台站地震数据处理结果表明,该极化滤波方法在台站地震资料分析和处理方面具有很好的直观性和较高的分辨率。 相似文献
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《地球物理学进展》2015,(6)
极化分析方法在多分量地震资料处理中起着举足轻重的作用,当波形初至很接近时,利用常规的时间域极化分析方法刻画不同波型的极化分布就变得比较困难了.基于此,在广义S变换时频方法的基础上,实现了一种时频域瞬时极化滤波方法.该方法根据多分量信号的时频谱及瞬时相位来计算瞬时极化参数(极化轴、极化率、平面化向量等).结合了时频分析方法的优势,在波形识别方面更加准确.通过极化率可以识别并分离线性极化波和椭圆及圆形极化波,通过平面化向量与各分量之间的夹角大小,定性识别平面波和非平面波.模型勘探数据及实际三分量台站地震数据处理结果表明,时频域瞬时极化滤波方法在波场分离及非平面波压制等方面具有一定的实用性. 相似文献
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针对陆上三分量地震资料去噪处理中面临的面波噪声能量强、有效信号能量弱、转换波与面波主频叠置、非矢量保真处理等问题,本文基于多分量数据中有效信号与强面波噪声在极化属性、振幅能量、视速度三方面的特征差异,提出了一种时频域压制多分量数据强面波的去噪方法,并设计了相应的矢量滤波器。该方法利用小波变换将地震信号变换到时频域,并基于时频域瞬时极化率公式计算出各点极化率参数,然后根据面波视速度划分出有效信号区和面波噪声区,并据此对有效信号进行能量均值统计,最后联合极化率、能量、频率特征对噪声识别和分频、分区压制。理论模型和实际资料处理验证了本文方法的正确性和有效性,为解决低信噪比陆上多分量资料面波压制提供了又一种有效手段。 相似文献
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很多地区地震资料的信噪比较低,而用于压制与信号具有不同方向的随机噪声的常规二维滤波方法常常产生假信息。基于相邻信号具有相干性这一假设,本文提出了一种叠后衰减随机噪声的多道滤波方法。该方法利用信噪比最高的中频段信息(含有主频的这一频率区间)分时窗计算信号单位矢量,并将该时窗内全频段数据向信号单位矢量方向投影,对各时窗(包括时间方向和空间方向)重叠部分按比例进行加权。我们利用这种方法对含有陡倾角的合成地震数据和海上二维实际地震资料进行了处理,处理效果很好。这种方法较为费时,但不受倾角限制,应用范围广。 相似文献
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Seismic directional random noise suppression by radial‐trace time–frequency peak filtering using the Hurst exponent statistic 
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下载免费PDF全文 Radial‐trace time–frequency peak filtering filters a seismic record along the radial‐trace direction rather than the conventional channel direction. It takes the spatial correlation of the reflected events between adjacent channels into account. Thus, radial‐trace time–frequency peak filtering performs well in denoising and enhancing the continuity of reflected events. However, in the seismic record there is often random noise whose energy is concentrated in certain directions; the noise in these directions is correlative. We refer to this kind of random noise (that is distributed randomly in time but correlative in the space) as directional random noise. Under radial‐trace time–frequency peak filtering, the directional random noise will be treated as signal and enhanced when this noise has same direction as the signal. Therefore, we need to identify the directional random noise before the filtering. In this paper, we test the linearity of signal and directional random noise in time using the Hurst exponent. The time series of signals with high linearity lead to large Hurst exponent value; however, directional random noise is a random series in time without a fixed waveform and thus its linearity is low; therefore, we can differentiate the signal and directional random noise by the Hurst exponent values. The directional random noise can then be suppressed by using a long filtering window length during the radial‐trace time–frequency peak filtering. Synthetic and real data examples show that the proposed method can remove most directional random noise and can effectively recover the reflected events. 相似文献
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Dispersion analysis is an important part of in-seam seismic data processing, and the calculation accuracy of the dispersion curve directly influences pickup errors of channel wave travel time. To extract an accurate channel wave dispersion curve from in-seam seismic two-component signals, we proposed a time–frequency analysis method based on single-trace signal processing; in addition, we formulated a dispersion calculation equation, based on S-transform, with a freely adjusted filter window width. To unify the azimuth of seismic wave propagation received by a two-component geophone, the original in-seam seismic data undergoes coordinate rotation. The rotation angle can be calculated based on P-wave characteristics, with high energy in the wave propagation direction and weak energy in the vertical direction. With this angle acquisition, a two-component signal can be converted to horizontal and vertical directions. Because Love channel waves have a particle vibration track perpendicular to the wave propagation direction, the signal in the horizontal and vertical directions is mainly Love channel waves. More accurate dispersion characters of Love channel waves can be extracted after the coordinate rotation of two-component signals. 相似文献
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三维VSP资料中,各种不同类型的波混杂一起形成复杂的波场.因此,波场分离是三维VSP数据处理关键的第一步.从不同波场的偏振方向和传播方向之差异着手,提出了一种高保真的VSP波场分离方法.首先通过射线追踪和偏振滤波的结合,把复杂波场(分解为简单波场;然后根据简单波场中不同波的传播方向截然相反的特点,进行方向滤波,达到波场分离的目的.实际数据处理表明,与常规波场分离方法相比,本方法大大降低了混波作用以及由此而生的波形畸变. 相似文献
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基于方向性滤波的地质体突出显示(英文) 总被引：1，自引：1，他引：0
为了突出地质体的轮廓并保证横向分辨率,在进行滤波的同时必须保证地质体的边缘。为此,引入了各向异性扩散滤波技术。该技术的核心思想是沿着边缘的方向扩散滤波,而垂直边缘的方向则不扩散,这样就保证了滤波具有方向性。为了增强该技术的实用性,对各向异性扩散模型的参数进行了讨论,在充分考虑地震分辨率的情况下,给出扩散系数公式,推导分析了扩散门限参数的选取原则。依据本文提出的公式及原则,对XX区的潮道、YY区的砂体进行了突出显示,良好的应用效果证实了本文提出的参数选取原则是合理的。 相似文献
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基于小波包分解的地层吸收补偿 总被引：19，自引：1，他引：18
在分析地震反射波勘探信号小波包分解特性的基础上,提出了基于小波包分解的地层吸收补偿方法．如果没有地层吸收,浅层反射波和深层反射波具有相同的振幅谱而相位谱相差一线性相位．如果把地震记录分成不同的频段,不同频段对于时间的能量分布关系具有相似性,即对所有频段的深层反射的能量与同一频段浅层反射能量之比应该相同;只是不同频段的绝对能量大小不一样．由于地层的吸收造成各频段能量对时间的分布不同,如果给这些频段乘以时变权使各频段能量对时间的分布相同,就起到了对地层吸收的补偿作用．该方法首先用小波包对地震勘探信号进行分频,然后根据地层吸收的特点,在每一个频段上分别提取每一个时间点的吸收系数并用其倒数加权每一个小波包系数,再用加权后的小波包系数重构地震反射波记录消除地层吸收．该方法适合Ｑ值未知的情况,对变Ｑ和常Ｑ都能适应．从实际应用效果看,该方法能很好的补偿地层的吸收。 相似文献
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The traditional method of exciting channel waves in coal deposits underground consists of firing explosive sources in a mid-seam position generating seam waves of the Rayleigh and Love type. We investigate various source positions and excitation mechanisms within the bedrock structure surrounding the seam to evaluate the effects of source positions adjacent to the seam. The investigation is based on analogue and numerical modelling of half- and full-space cases, for which the excitation and the nature of Rayleigh channel waves are examined. In the analogue modelling, sources, located from mid-seam out into the bedrock, along the edge of a 2D plate model, excited channel waves through a conversion of the free surface Rayleigh wave at the edge of the plate. The excited channel wave belongs to the normal mode range. Frequency-wavenumber analysis shows that the symmetric 2nd mode of the channel wave is excited with frequencies comparable to the forcing frequency of the source signal. The polarization changes from retrograde to prograde, as the wave develops from the front to the rear of the seam, respectively. The amplitude-depth distribution resembles that of an ordinarily excited seam wave, for the symmetric component. However, the antisymmetric component does not show the characteristic change of sign in amplitudes across the mid-seam axis. Numerical modelling with sources located in the bedrock (full-space case) shows that relocating the source away from the seam lowers the frequency content of the excited channel wave. Based on these investigations, the influence of a lower-frequency source signal on the excitation of the channel wave is examined in an analogue experiment. Sources are sited in the bedrock adjacent to the seam at three locations. A lower-frequency wavelet is calculated for each source location from the results obtained in the numerical analysis. For comparison, a higher-frequency wavelet is also used which is known to be optimal for this model geometry when excited by a mid-seam source location. It is found that in two cases the use of the lower-frequency wavelet improves the channel wave excitation, while no amplification is achieved in one case. 相似文献
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时频峰值滤波(TFPF)算法是一种非常有效的去噪方法.但是传统的TFPF采用的单一窗长,并且仅沿时间方向进行滤波,忽略了信号的空间信息,并且TFPF近似等效成一个时不变的低通滤波器,不能追踪快速变化的信号.针对这些问题,引入空间局部加权回归自适应TFPF(SLWR-ATFPF).鉴于随机噪声在各个位置的方向随机性,以及有效信号在各个位置的方向确定性,首先利用空间局部加权回归(SLWR),对含噪信号进行空间加权,从而使加权之后的信号包含空间信息.然后,再引入凸集和Viterbi的思想,对空间加权之后的信号进行自适应滤波.从而,完成时空域二维自适应滤波.将SLWR-ATFPF应用于合成记录和实际的共炮点记录,实验结果表明,改进的方法与原算法相比,能够在压制低信噪比(SNR)随机噪声的同时更好地保留有效信号. 相似文献
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In this paper we study the S wave basement velocity structure and S wave splitting and polarization anomalies using the three
component records of deep seismic sounding in the Three Groges Dam area, and further discuss the methods to study the anisotropy
of crustal medium, the direction of regional tectonic stress field, and the physical indicator of potential earthquake sources
using shear wave splitting and polarization anomalies. It has been demonstrated by analyzing the DSS data in the Three Gorges
Dam area that S wave splitting and polarization anomalies are reliable means for studying seismic anisotropy of crustal medium
and the direction of regional tectonic stress field. At the same time, it has been shown that DSS data are very useful for
widening S wave observing window and distinguishing anomalous body, because DSS data have the advantage that the source position
is known prior and S wave ray path can be traced exactly.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 1–3, 1993. 相似文献