Using Captured Data by RGB-D Video Sensor in Numerical Simulation Environment for the Development of New Microwave Personnel Screening System

Appeared on the market a decade ago devices, capable of capturing a depth map of the scene with high spatial resolution and video frame rate, are frequently used in research in all areas of science and engineering where possibility of measuring depth at no additional cost gives a significant advantage. In the proposed paper, an application of such a device, an RGB-D videosensor, is considered for capturing the motion of a walking person with the aim of numerical simulation of the microwave personnel screening system of a new kind. In such a microwave screening system the synthetic aperture, required for obtaining the radar image with high spatial resolution, is formed by subject's natural motion in the vicinity of a sparse stationary antenna array. The radar image for the whole surface of the subject's body is computed with the trajectories of the articulated body parts provided by the RGB-D sensor data using modern computer vision methods. This paper describes the numerical experiments in which the trajectories of body parts were captured using graphical markers attached to the body of a volunteer. The captured trajectories were used as the trajectories of foreign objects concealed under clothing to calculate the expected radar signal in user-defined antenna arrays. The processing of the radar signal was done with the trajectory of the foreign object taken into account by focusing the radar signal into the area defined around the foreign object, containing it, and moving with it as a whole. The described simulation technique allowed estimating the influence of the following modeling parameters on the resolution of the obtained radar images: the spatial configuration and quantity of transmit and receive antennas in the antenna array, the frequency band and bandwidth of the radar signal, the positioning of foreign objects on different parts of the human body, the length of the trajectory, and the positioning errors. The numerical simulations accomplished with the described technique are required for defining the technical requirements for the new microwave screening system, including the number of transmit and receive channels, the type of the antenna array (monostatic, quasi-monostatic, or multistatic), antenna spatial configuration. The demonstrated results help understanding the capabilities of such a microwave personnel screening system to properly form the radar images of concealed objects and its limitations.