Ultra-wideband radar based human body landmark detection and tracking with biomedical constraints for human motion measuring

In this manuscript, we propose and investigate a methodology for detecting and tracking human body landmarks using ultra-wideband (UWB) radars. The detection of multiple human body landmarks (HBLs) is achieved by motion target indication techniques, and the multi-HBL tracking is accomplished by a novel iterative convex optimization based approach with considerations of biomechanics constraints. Specifically, the radar signals returned from radio frequency (RF) reflective markers attached to the HBLs are extracted and processed. Then moving target indication (MTI) and constant false alarm rate (CFAR) detection techniques are then used for detecting the reflectors. The data association (DA) is then applied to validate and relate the detection results to target landmarks for generating range measurements. The range measurements are used for a convex optimization based sequential estimation algorithm to sequentially estimate the accurate marker locations. It is noted that the proposed optimization based sequential estimation is able to incorporate biomechanical constraints. In our field experiment, two RF reflective markers are attached to the wrist and elbow of one human arm for reflecting radar signals. It is demonstrated that detection and tracking of the moving trajectories of two markers are feasible and successfully achieved, and thus, the human arm motion is accurately measured using one UWB radar.