基于内部谐振的弱信号补偿介电目标重构算法

Target Reconstruction Method for Weak Signal Compensation Based on Internal Resonances

对断裂或下沉路基等电大尺寸异质体目标重构其几何特征(如位置,形状,尺寸等),在环境地质等工程应用及市政基础设施维护中尤为重要。然而由于电磁波在目标体内部的衰减,使得目标下表面反射回波很弱。对此该文提出一种基于内部谐振的弱信号补偿目标重构算法。由于有限目标边界的限制,电磁波在目标体内部沿传播方向产生多次反射,此现象在采样时间记录信号上体现为周期谐振。分析了谐振周期与目标宽度的关系并由此估计目标下表面的位置,结合去除虚像以后的目标前表面位置,重构目标形状。实验结果验证了提出方法的有效性以及对噪声的鲁棒性。

The geometric characteristics （such as position, shape, size, etc.） of a large size target such as the broken or sinking subgrade are particularly important in engineering applications and municipal infrastructure maintenance. Due to the attenuation of the electromagnetic wave inside the target, the reflection from back surface of the target is too weak to be detected. In this paper, a target reconstruction algorithm for weak signal compensation based on internal resonances is proposed. Due to the limited target boundary, the electromagnetic wave will produce multiple reflections along the propagation direction inside the target. This phenomenon is reflected as periodic resonances in the recording signal. The relationship between the resonant period and the target width is analyzed and the position of the back surface of the target is estimated. The virtual image around the front surface of target is removed by means of phase difference. The whole target shape is reconstructed according to the front surface and back surface of the target. The experimental results verify the effectiveness of the proposed method and the robustness to noise.