New interpretative way to the method of underground electromagnetic waves - the establishment of recognizing patterns

The acquisition subsystem of underground electromagnetic wave new system in frequency domain can provide multi - frequency and multisource observation data at crosshole exploration .The data connotes information of attenuation, of propagating paths and scattering of geologic targets . The Tomographic algebraic algorithms such as ART,SIRT merely consider the attenuation of ray paths ;it hence can not apply to data processing and interpretation at complex geological conditions .