基于微分电导的航空瞬变电磁合成孔径快速成像方法研究

Fast imaging of correlation stack for airborne TEM based on differential conductance

直升机航空瞬变电磁法一次作业覆盖面积广,数据采集量巨大,信息丰富,对于剖面成像解释有很大的优势.本文利用航空电磁数据量大的优势,采用微分电导参数与相关叠加相结合的技术,实现航空瞬变电磁快速成像解释.首先,利用等效导电平面法求取视纵向电导与视深度.然后,将纵向电导对视深度求二次导数获得微分电导参数.最后,利用相关叠加算法对微分电导数据进行合成,形成合成后的微分电导剖面,实现航空瞬变电磁相关叠加快速成像.利用文中所述的成像算法对模型数据和航空瞬变电磁实测数据进行解释分析,结果表明基于微分电导的相关叠加成像算法不仅具有很好的抗噪性,而且计算速度快可以进行实时成像,对于地下介质的电性分层具有较好的分辨,有效提高了航空瞬变电磁法的解释精度.

Helicopter airborne transient electromagnetic method has such advantages as large cover area,mass data and rich information,which are favorable for section imaging.This paper takes these advantages and uses differential conductance and correlation algorithm to realize fast imaging for helicopter airborne transient electromagnetic method.Firstly,floating plate theory is used to get apparent longitudinal conductance and apparent depth.Secondly,take the derivative of apparent longitudinal conductance with apparent depth to get differential conductance. Lastly, adopt correlation algorithm to get differential conductance section to realize fast imaging for helicopter airborne transient electromagnetic method. With analysis of synthetic model and field data,the results show that our method has excellent anti-noise property and fast speed,which can be used for real time imaging.Besides,it has high resolution for electrical interface and improves the interpretation precision of airborne transient electromagnetic method.