一种从低信噪比地震资料中提取信号的方法

采用改进的时空变小波阈值去噪与叠加技术相结合的方法实现从低信噪比地震资料中提取信号。为减小经典小波阈值去噪产生的过扼杀或过保留现象，选用中值与叠加结果对去噪结果进行约束，并以此为基础改进了经典小波阈值去噪方法。地震资料进行小波变换之后，对每一小波尺度下的各道的每一小波系数用改进方法去噪，然后小波重构，得到去噪后记录。应用多个小波重复上述操作，得到多道去噪后的记录，将这些多道记录叠加，实现增强信号的目的。理论分析及数据测试表明，该方法能从低信噪比地震资料中准确提取信号，且处理效果明显优于常规处理方法。

A method of signal extracting in low SNR seismic data

The combination of improved wavelet threshold denoising and stacking technologies is useful to extract signals from low SNR seismic data. After wavelet transform, the spatial-temporal threshold of the wavelet coefficient of each seismic trace is calculated in every wavelet scale. In order to diminish over-smoothing or over-preserving in classic wavelet threshold denoising, both median filtering and stacking are used as constraints in denoising. Classic wavelet threshold denoising is modified based on the above method to realize wavelet threshold denoising. Finally, denoised seismic data can be obtained after wavelet reconstruction. Using multiple wavelets to repeat the above operations, multiple denoised traces can be obtained. These traces can be stacked to extract signals from low SNR data. Both theoretical and real data show that this method is able to achieve accurate extraction of signals from low SNR seismic data, and the processing result is significantly better than conventional methods.