低频缺失下跨孔雷达包络波形反演

全波形反演方法作为一种高分辨率成像手段在跨孔雷达反演中得到有效应用,但其仍受局部最小问题影响。一个有效的解决方法是为反演提供一个准确的初始模型。但在应用真实雷达数据时,由于地下介质未知且存在低频数据缺失的情况,全波形反演往往难以获得理想结果。为此,使用对包络目标函数求导的方法,详细推导了包络波形反演的梯度公式。该方法与传统全波形反演方法在原始数据低频成分缺失情况下的反演结果对比表明,该方法能够有效还原缺失的低频信息并且对低频缺失数据有更好的反演能力,可以直接为地下介质提供定量解释。

Envelope Waveform Inversion of Cross-Hole Radar Without Low Frequency Data

The full waveform inversion(FWI)has been used as a high resolution imaging method for cross-hole radar inversion;however,it is still trapped by local minimum.An effective way is to provide an accurate initial model for FWI.The fact is that the underground media is unknown,and the low-frequency information are usually not available in the GPR field data,which lead to difficult to achieve accurate result in FWI.The gradient formula of envelope waveform inversion (EWI)is deduced in detail by using the method of derivation of the envelope obj ective function.In comparison with the inversion result of the traditional FWI,the EWI has a better inversion ability for low-frequency missing data,and can effectively restore the missing low-frequency information.It can provide quantitative interpretation for subsurface media.