“…Radio frequency (RF) sensing is an emerging research field and has attracted considerable attentions. It impels many remarkable applications, such as indoor localization [1], [2], [3], [4], gesture recognition [5], [6], fall detection [7], robot navigation [8], [9], [10] and human motion tracking [11], [12]. Despite the success in diverse applications, recent years have witnessed the rapid proliferation of RF-based human imaging technologies, which provide privacy-preserving services for applications like surveillance, security inspection, and health monitoring.…”