Research On Efficient Simulation Technology Of Millimeter Wave Active And Passive Composite Human Body Security Inspection Imagin

In today’s complex public security situation at home and abroad,people’s attention to human safety inspection is increasing year by year.Compared with X-ray,millimeter wave has lower photon energy and will hardly bring damage to the human body.Compared with infrared,millimeter wave has excellent penetration capability.Therefore,millimeter wave imaging technology has become a desirable and irreplaceable means of human security.Millimeter wave security imaging data are obtained by measurement or simulation.Simulation provides theoretical support for the design of millimeter wave imaging system,but the calculation time is very long.In order to improve the simulation efficiency of millimeter wave passive/active human security imaging,the following research work is carried out in this thesis:1.The emissivity calculation models of surface are given.It includes smooth planes and rough surfaces.The imaging principles of millimeter wave passive imaging and active imaging are introduced.2.In the passive security imaging,the reverse ray tracing algorithm is used to calculate the radiation brightness temperature and draw the radiation brightness temperature distribution map.An advanced fast physical optics method is proposed to calculate the emissivity of rough surface.The proposed algorithm has a wider application range than the conventional analytical approximation method and has higher calculation efficiency than the traditional physical optics method.Finally,the millimeter wave passive imaging results using smooth plane emissivity and rough surface emissivity are compared and analyzed.3.In the active millimeter wave security imaging,a fast multi-graphics processing unit(GPU)parallel simulation method is proposed.It uses multi-GPU hardware to accelerate the shooting and bouncing ray method in simulating the millimeter wave scattering echo and employs narrow beam antenna scanning to obtain high-resolution millimeter wave active human security three-dimensional simulation images.Several typical security scene examples are given to illustrate the obvious acceleration effect of the proposed method.