Research On The Simulation Method Of The Security Check Scene Based On Passive Millimeter-wave Imaging

As a new imaging method,passive millimeter-wave(PMMW)imaging has been used in the fields of military target detection,human security inspection,mountain mapping modeling and other fields.Therefore,passive millimeter-wave imaging has a wide range of application scenarios and greet research value.Through the radiation imaging simulation of the observation scene,it is not only helpful to recognize the radiation characteristics of the target,but also has guiding significance for the design of the new imaging system.At present,the research of human security imaging based on passive millimeter wave mainly focuses on the system optimization and image processing algorithm of security imaging system,but few people mention the simulation research of human security imaging based on passive millimeter wave.Therefore,this thesis launches passive millimeter wave imaging simulation for human security inspection scene,and the main work includes:(1)Proposed a passive millimeter wave imaging simulation model for micro-rough surface,based on the rough characteristics of human skin in security inspection scene.Expounded the multilayer brightness temperature tracking and inversion model,and deduced the calculation method of scattering coefficient of deep-rough surface and micro-rough surface.The influences of rough parameters,relative complex dielectric constant of rough surface and polarization mode on the scattering coefficient of rough surface are researched in this thesis.The brightness temperature imaging simulation of random deep rough surface and random micro-rough surface are carried out,and the influences of roughness,polarization mode,relative complex dielectric constant on brightness temperature value are researched in this thesis.(2)Aiming at the detection scene of hidden dangerous goods,established a passive millimeter wave brightness simulation model of layered media,expounded the tracking and inversion process of the model,deduced the calculation method of transmission coefficient of Gaussian deep rough surface,and researched the influences of roughness parameters on transmission coefficient.The brightness temperature imaging simulation of typical hidden dangers such as knives,pistols and gasoline are carried out,and the influences of fabric roughness,ray interval and hidden depth of hidden objects on brightness temperature imaging are researched.(3)Aiming at the complex transmission scene in human security inspection,proposed an improved transmission model to deal with the multi-angle transmission problem.The traditional transmission model only considers the transmission surface at a single angle,so it is only suitable for simple scenes such as detecting buried objects in sand.The improved model deals with the multiangle transmission problem by establishing a local coordinate system on the transmission surface,which is suitable for the human security scene model with multi-angle transmission surface,improves the application scope of passive millimeter wave imaging simulation.(4)Aiming at the typical micro-rough surface scene and human security scene,carried out imaging simulation and experimental verification.By comparing the measured results with the simulation results,verified the effectiveness of the micro-rough surface model,the human security model and their imaging methods,analyzed the relative error between the simulation results and the measured results.