Preface to the special topic on SAR microwave vision 3D imaging

<正>Synthetic Aperture Radar(SAR) has significant applications in terrain mapping, environmental monitoring,disaster investigation and many other fields. Traditional SAR acquires two dimensional(2D) images of the observed scenarios, while interferometric SAR(InSAR) can acquire digital surface model(DSM, 2.5D images). However, in areas with steep terrain changes or complex infrastructures, there will be severe layover phenomenon, resulting in many targets being difficult to detect and interpret. SAR 3D imaging can solve this problem and significantly enhance the target recognition and 3D modeling capabilities. It has become an important trend in the current development of SAR technology. Currently, SAR 3D imaging techniques mainly utilize multi-incident-angle observations to construct a synthetic aperture in the third dimension, so as to obtain the third dimensional resolution ability. However, dozens of tomographic flights or multi-channel observations are required, leading to long data acquisition cycles or extremely sophisticated radar systems,which restrict its popularization.