基于改进振幅衰减常数的无线电波透视层析成像研究

Study on the tomography of radio-wave penetration based on improved amplitude attenuation constant

为提高无线电波透视的探测精度,将改进的振幅衰减常数引入层析成像技术,给出改进的振幅衰减常数表达式,该常数不仅与电导率、介电常数、频率等参数与有关,而且与电磁波入射角度密切相关.基于射线理论采用阻尼约束的代数重建算法(ART)对陷落柱模型进行层析成像模拟,分析对比改进振幅衰减常数与经典振幅衰减常数的绝对衰减层析成像和相对衰减层析成像的反演重建效果.结果表明:改进振幅衰减常数的成像效果显著优于经典振幅衰减常数;绝对衰减层析成像对构造的横向定位较为准确,相对衰减层析成像容易造成真实构造的局部缺失.将改进的振幅衰减常数应用于工作面隐伏陷落柱的实际探测工作,取得了良好的应用效果.

In order to improve the precision of radio wave penetration, amplitude attenuation constant was improved, and which was used in radio wave penetration tomography. The expression of improved amplitude attenuation constant was shown associated with not only electrical conductivity, dielectric constant, frequency, but closely related to the incident angle. Based on direct ray theory, the simulation of subsided column models were completed using Algebra Reconstruction Technology （ART）. The reconstruction effect can be easily analysised and contrasted about absolute and relative tomography using improved or classical amplitude attenuation constant. The results shown that the effect of modified attenuation constant is significantly better than the classical attenuation constant. Absolute tomography imaging is more accurate in the constructs＇ transversal orientation, but relative tomography imaging is easy to lose the real structures. Finally, according to the simulation results, using the improved amplitude attenuation constant to detect the subsided column at the working face and achieved a good effect.