Study on an adaptive regularized 1D inversion method of helicopter TEM data
Study on an adaptive regularized 1D inversion method of helicopter TEM data
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发表时间：
2011
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通讯作者：
Mao Li-feng;Chen Bin
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作者：
Mao Li-feng;Chen Bin
中国目前还没有机载瞬变电磁系统或解释软件。因此，有必要开发一套机载电磁信号时域解释软件。以中央环直升机瞬变电磁（TEM）机载电磁数据的一维反演算法为例进行了理论研究。由于机载瞬变电磁法的反演是一个典型的病态问题，存在严重的多解问题，需要提高反演算法的稳定性。为此，本文采用了一种基于自适应正则化的一维反演解释方法，分别采用最光滑、最平坦和最小约束模型获得反演结果。在迭代原因中，基于数据目标函数与模型目标函数的关系，自适应计算正则化反演算法的自适应规则因子；这种计算方法可以避免重复搜索规则因子，在反演迭代过程中收敛速度快、稳定。本文在介绍该算法后，以分层模型的理论响应为例对该反演方法进行了验证。对三种约束模型的反演结果进行了分析和比较。反演结果表明，该算法可以采用齐次半空间模型作为初始模型，对三种约束模型均可进行不到10次迭代反演，并能较好地重建理论模型。反演结果表明，自适应正则化反演算法稳定可靠，满足机载瞬变电磁的要求。
China does not airborne transient electromagnetic system or interpretation software up to now.So it s necessary to develop a set of interpretation software for airborne electromagnetic in time-domain.The 1D inversion algorithm of airborne electromagnetic data of central-loop helicopter transient electromagnetic (TEM) is studied theoretically as an example in this paper.Since the inversion of airborne TEM is a typical ill-posed problem,it has serious multi-solutions and is necessary to improve the stability of the inversion algorithm.For this purpose,a onedimension inversion interpretation method based on adaptive regularization has been used in this paper,and the inversion results can be obtained using the smoothest,flattest and smallest constraint model respectively.In the cause of iteration,the adaptive regular factor of the regularized inversion algorithm is calculated adaptively based on the relation of the data object function and the model object function;this kind of calculation method can avoid searching the regular factor repeatedly and can be result in a rapid and stable convergence in the iteration course of the inversion. In this paper,the inversion method is tested using theoretical responses of layered models as an example after the algorithm is introduced.The inversion results using the three kind of constraint model are also analyzed and compared.The inversion results demonstrate that the inversion algorithm can use homogeneous half-space model as the initial model and can reconstruct the theoretical model well using less than 10 iterations inversion for all the three kind of constraint model.The inversion results also show that the adaptive regularized inversion algorithm is steady and reliable,meeting the requirements of airborne transient electromagnetic.