最小均方误差算法在瞬变电磁信号降噪中的应用  

Application of minimum mean square error algorithm in transient electromagnetic signal denoising

作　　者：刘帅 曾庆宁[1] 郑展恒[1] LIU Shuai();ZENG Qing-ning;ZHENG Zhan-heng(School of Information and Communication,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]桂林电子科技大学信息与通信学院,桂林541004

出　　处：《地球物理学进展》2020年第5期1826-1831,共6页Progress in Geophysics

基　　金：广西自然科学基金(2016GXNSFDA380018);国家自然科学基金项目(61961009);“认知无线电与信息处理”教育部重点实验室基金项目(CRKL160107,CRKL170108);桂林电子科技大学研究生教育创新计划资助项目(2019YCXS031,2019YCXS034)联合资助.

摘　　要：瞬变电磁信号实测数据容易受到随机噪声和人文干扰的影响,使得数据特征和地质反演结果出现偏差,本文基于最小均方误差(MMSE)原则,实现瞬变电磁信号的降噪,以提高数据的解释精度.首先对瞬变电磁信号进行分帧处理,计算每一帧的短时频谱幅度,然后估算出先验信噪比和后验信噪比,最小化估计幅值与实际幅值之间的均方误差,最后结合带噪信号的相位信息,得到估计的增强信号.模拟数据和实测数据的实验结果表明,MMSE算法能够有效去除随机噪声和人文干扰,提高信噪比,与均值滤波、中值滤波、小波滤波三种降噪方法相比,处理后的信号曲线更加平滑,接近纯净的瞬变电磁信号衰减曲线.The practical accquired data of transient electromagnetic signal are easily interfered by random noise and human interference,which makes the data feature and geological inversion result appear deviation.Based on the principle of Minimum Mean Square Error(MMSE),the denoising method of transient electromagnetic signal is realized in this paper,so that the interpretation precision of data is improved.Firstly,the transient electromagnetic signal is processed in frames,and the short-term spectrum amplitude of each frame is calculated.Then,the prior SNR and the posterior SNR are estimated,and the mean square error between the estimated amplitude and the actual amplitude is minimized.Finally,the phase information of the noisy signal is combined to obtain the estimated enhanced signal.The experimental results of simulated data and practical acquired data show that MMSE algorithm can effectively remove random noise and human interference and the signal-to-noise ratio has been greatly improved.Compared with the three denoising methods including mean filtering,median filtering and wavelet filtering,the signal curve after denoising is smoother and close to the decreasing cure of clear transient electromagnetic signal.

关 键 词：瞬变电磁信号 最小均方误差 先验信噪比 后验信噪比 降噪 

分 类 号：P631[天文地球—地质矿产勘探]