A Novel CT-Mode Through-the-Wall Imaging Method Based on Time Delay Estimation

Through-the-wall (TTW) imaging is an important class of applications with the goal of sensing the environment inside the unknown area. In the computerized tomography (CT)-mode TTW imaging method, the layout of the area is reconstructed with the received signal strength (RSS). However, the multipath included in the RSS is difficult to mitigate, resulting in blurring, wall missing, or ghosts. In this letter, a novel imaging method is proposed. First, the received signal is processed by pulse compression. The multipath signals are separated from the directly transmitted wave (DTW), and then, the time delay of the latter one is easily estimated. Second, an improved total variation regularization algorithm is used to reconstruct the layout by assuming that there are only horizontal and vertical walls in the area. The validity of the proposed method is verified by the experimental results, where a clearer image could be obtained compared with the one generated by the traditional RSS method.