Research On The Imaging Technology Of MIMO Millimeter Wave Radar Based On Security Inspection

Facing the increasingly tense international situation and increasing terrorist attacks,it has become necessary to implement security checks in public areas with high throughput of people.Traditional security screening methods can no longer meet the needs of efficient and comprehensive security screening.Millimeter wave imaging technology,due to its high imaging quality,the capacity to operate continuously,and other benefits,has been given much attention in the field of security screening due to the advancement of computer hardware capability.Moreover,millimeter wave security radar has become a popular subject of study for both domestic and foreign scholars in recent years.In this thesis,the Multiple-Input Multiple-Output(MIMO)millimeter wave radar imaging technology in the security screening situation is studied.The main research work of this thesis is as follows:(1)To address the imaging mode selection problem,the geometric models of three classical imaging modes(planar scan mode,cross-cross array mode and straight-arm rotating array mode)and the corresponding IF echo expressions are discussed,and the three imaging modes are verified by simulation experiments.To address the problem of low imaging efficiency of the time-domain matched filtering algorithm,a fast imaging algorithm is designed for the three imaging modes in this thesis,and the feasibility of the algorithm is demonstrated by simulation experiments and actual measurement data.(2)To solve the problem of sparse array imaging in security screening scenarios,a compression-aware sparse array imaging algorithm is designed in this thesis.Proposing scene chunking as a solution to the issue of too much computation in compressed sensing imaging,the algorithm’s complexity is significantly reduced.Additionally,by adjusting the noise threshold,the issues resulting from incorrect sparsity settings are circumvented and the reconstruction time is significantly decreased.Simulations have also demonstrated the practicality of using this imaging algorithm for sparse array imaging.(3)A 3D imaging algorithm that can automatically determine the depth of field of the target is proposed for the imaging problem in the case of multiple depths of field.The inspected person or object only needs to stand in a range,and the security system can detect the distance between the target and the scanning plane by constant virtual police,and the objects under different depths of field are displayed by means of 3D imaging.Results of both the simulation and actual measurements demonstrate the practicality of the plan,furnishing a theoretical basis for the investigation of non-cooperative security screening.