基于稀疏表达的OBS去噪方法  

Denoising methods of OBS data based on sparse representation

作　　者：南方舟 徐亚[1,2] 刘伟[1,2,3] 刘丽华[1,2] 郝天珧 游庆瑜[1,2,3] NAN FangZhou1,2,3 , XU Ya1,2, LIU Wei1,2,3 , LIU LiHua1,2 , HAO TianYao1,2,3 , YOU QingYu1,2,3(1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Key Laboratory of Petroleum Resource Research, CAS,Beijing 100029, China; 2 Institutions of Earth Science, Chinese Academy of Sciences, Beijing 100029, China; 3 University of Chinese Academy of Sciences, Beijing 100049, Chin)

机构地区：[1]中国科学院地质与地球物理研究所中国科学院油气资源研究重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049

出　　处：《地球物理学报》2018年第4期1519-1528,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金(91428204;41374139;U1505232);中国科学院战略性先导科技专项(XDB06030200)联合资助

摘　　要：海底地震仪(OBS)采集数据的去噪处理是开展OBS震相分析及后续处理反演的基础.本文结合曲波(Curvelet)变换及压缩感知提出一种稀疏化表达的OBS去噪方法,并通过与小波变化对比等探讨去噪效果.曲波变换具有抛物尺度及识别线性异常的优点,可以稀疏地表示OBS数据,再结合压缩感知思想对稀疏表达OBS数据进行去噪处理和重构.通过对变换后的系数进行基于L1范数的冷却阈值迭代滤波,获得最优的变换系数,本文指出基于曲波变换的冷却阈值迭代法能够很好地对OBS数据去噪.对比小波和曲波两种变换在相同迭代次数下对理论模型数据进行去噪处理,表明曲波变换得到的结果信噪比更高.利用本文方法对渤海地区采集的OBS数据进行去噪处理获得了更加清晰连续的震相,噪声压制效果更明显,为震相拾取及后续速度模型反演奠定了良好的基础.Noise suppression is the basis for OBS data interpretation and subsequent inversion.Combining Curvelet transform and compression sensing,we propose a noise suppression method for OBS data using sparse representation.Comparing to the wavelet method,the Curvelet transform has advantage in identifying linear anomalies on a parabolic scale,which permits to reconstruct OBS data in a sparse representation domain.The sparse data is enhanced and reconstructed by the means of compression sensing,followed by transforming the coefficient to get iterative filtered by the cooling threshold of L1,then an optimal coefficient is resolved.Our study shows iterative filtering in the Curvelet domain with a cooling threshold can be utilized in noise suppression of OBS data.Comparison of wavelet and Curvelet transforms shows that the Curvelet method has a better S/N ratio in the circumstance of the same amount iterations of noise suppression.We use this new method to enhance the OBS data signal acquired from the Bohai Bayexperiment and show clearer identification of the seismic phases and better S/N ratios,which facilitates picking up seismic phases from data and subsequent inversion of velocity models.

关 键 词：OBS 稀疏表达 字典 压缩感知 曲波变换 L0/L1反演 

分 类 号：P631[天文地球—地质矿产勘探]