A wavelet-based baseline drift correction method for grounded electrical source airborne transient electromagnetic signals
A wavelet-based baseline drift correction method for grounded electrical source airborne transient electromagnetic signals
复制标题
基于小波的接地电源机载瞬变电磁信号基线漂移校正方法
DOI：
10.1071/eg12078
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发表时间：
2013-12
影响因子：
0.9
通讯作者：
Yang, Guihong
中科院分区：
文献类型：
--
作者：
Li, Suyi;Lin, Jun;Zhou, Fengdao;Yang, Guihong
飞艇接地电源机载瞬变电磁（GREATEM）系统具有较高的探测深度和空间分辨率，以及出色的探测效率和易于飞行控制的特点。然而，前端固定接收线圈的移动和摆动会导致严重的基线漂移，导致电阻率成像效果较差。因此，减少GREATEM基线漂移对于反演解释至关重要。为了校正基线漂移，传统的插值方法使用所有周期的计算起点和终点之间的线性插值来估计基线“包络”，并通过从原始信号中减去包络来获得校正信号。然而，发现去除的效果和效率很低。针对GREATEM数据基线漂移的特点，本研究提出了一种基于多分辨率分析的小波方法。通过反复试错的迭代比较确定最佳的小波基和分解层数。本应用采用10级分解的sym8小波，得到10级的近似值作为基线漂移，然后从原始信号中去除估计的基线漂移得到校正信号。为了检查我们提出的方法的性能，我们建立了浸渍板模型并计算了理论响应。通过仿真，我们比较了基于小波的方法和插值方法的信噪比、信号失真和处理速度。仿真结果表明，基于小波的方法优于插值方法。我们还使用现场数据来评估这些方法，比较分别使用原始信号、插值校正信号和小波校正信号的视电阻率深度剖面图像。结果证实，我们提出的基于小波的方法是一种有效、实用的消除 GREATEM 信号基线漂移的方法，其性能明显优于插值方法。
A grounded electrical source airborne transient electromagnetic (GREATEM) system on an airship enjoys high depth of prospecting and spatial resolution, as well as outstanding detection efficiency and easy flight control. However, the movement and swing of the front-fixed receiving coil can cause severe baseline drift, leading to inferior resistivity image formation. Consequently, the reduction of baseline drift of GREATEM is of vital importance to inversion explanation. To correct the baseline drift, a traditional interpolation method estimates the baseline ‘envelope’ using the linear interpolation between the calculated start and end points of all cycles, and obtains the corrected signal by subtracting the envelope from the original signal. However, the effectiveness and efficiency of the removal is found to be low. Considering the characteristics of the baseline drift in GREATEM data, this study proposes a wavelet-based method based on multi-resolution analysis. The optimal wavelet basis and decomposition levels are determined through the iterative comparison of trial and error. This application uses the sym8 wavelet with 10 decomposition levels, and obtains the approximation at level-10 as the baseline drift, then gets the corrected signal by removing the estimated baseline drift from the original signal. To examine the performance of our proposed method, we establish a dipping sheet model and calculate the theoretical response. Through simulations, we compare the signal-to-noise ratio, signal distortion, and processing speed of the wavelet-based method and those of the interpolation method. Simulation results show that the wavelet-based method outperforms the interpolation method. We also use field data to evaluate the methods, compare the depth section images of apparent resistivity using the original signal, the interpolation-corrected signal and the wavelet-corrected signal, respectively. The results confirm that our proposed wavelet-based method is an effective, practical method to remove the baseline drift of GREATEM signals and its performance is significantly superior to the interpolation method.
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影响因子：
4
作者：
S. U. Sigurdsson;R. Rupakhety;R. Sigbjörnsson
通讯作者：
S. U. Sigurdsson;R. Rupakhety;R. Sigbjörnsson
DOI：
10.1063/1.4823127
发表时间：
1992-05
期刊：
Computers in Physics
影响因子：
--
作者：
I. Daubechies
通讯作者：
I. Daubechies
DOI：
--
发表时间：
2008
期刊：
The Journal of Geology
影响因子：
--
作者：
Xing Wei-bing
通讯作者：
Xing Wei-bing
影响因子：
0.9
作者：
A. Davis;J. Macnae;T. Robb
通讯作者：
A. Davis;J. Macnae;T. Robb
影响因子：
2.6
作者：
Richard S. Smith
通讯作者：
Richard S. Smith