An Aperture Adaptive Scale Transform of Terahertz Radar Imaging Algorithm

Terahertz (THz) radar system can realize high-resolution imaging benefits from its advantages, such as wide bandwidth and short synthetic aperture time. However, due to the short wavelength in the THz frequency range, the multiscattering center effect of targets generally occurs. This article considers the mismatch between imaging aperture and target characteristics, leading to serious resolution degradation, imaging defocus, and loss of target details. We propose an aperture adaptive scale transform (AAST) imaging method, which is implemented in three steps. First, the subaperture is adaptively divided by matching the azimuth with the scattering characteristics. Then, the apertures, which contain different details of the target, are scaled by weight. Finally, the generalized likelihood ratio test (GLRT) method is used to reconstruct the fine image results of incoherent scale transformation, resulting in more detailed information and higher definition in imaging results. We use a THz radar system operating at 0.34 THz and with a bandwidth of 28.8 GHz to scan around a target. The imaging results of measured echo corroborate the validity of the proposed algorithm.