Research On Millimeter Wave Active Imaging Sparse Linear Array Design And Inmaing Method

Various terrorist attacks have brought great harm to various countries and regions,especially in crowded occasions,where terrorists have caused huge casualties and property losses through the dangerous objects they carry.In this context,on these occasions to introduce security equipment become effective protection to prevent terrorism And millimeter wave imaging technology is the mainstream of recent research,with its high penetration At present,some domestic and foreign millimeter-wave imaging systems have disadvantages such as large array,large number of array elements,high cost of system construction and complex data acquisition and processing,etc In this paper,the near-field millimeter-wave imaging system is built from the perspective of simplifying the number of array elements and combining with the suitable millimeter-wave imaging algorithm.The research is mainly carried out from the following three points.Firstly,the millimeter-wave imaging model under the traditional single-transmission and single-receiving array is introduced,and the reconstruction formula of millimeter-wave holography is deduced.Then,the image evaluation index is given by analyzing and comparing the reconstruction algorithm and Back Propagation(BP)algorithm based on the beam domain under the fast Fourier transform,and the sampling interval of the array is deduced The basic array parameter information such as azimuth resolution and range resolution is introduced,and the sparse principle of array is introduced.The principle of how to decompose the full array into a sparse array is analyzed,and the single-shot multi-receive scanning mode is carried out through this array.Secondly,a two-dimensional millimeter wave imaging model was built through FEKO,the antenna array was sparse,the BP alg orithm was improved,the principle of equivalent center was introduced,and the algorithm was adapted to the array sparseness.Then the single-shot single-receive array is designed,and the improved algorithm is used for imaging,the image evaluation index is compared,and the influence of signal and distance attenuation on the image quality is discussed.The sparse array imaging effect is compared with the full array image effect,and the pros and cons of the imaging results are analyzed..Finally,the 3D imaging model was established,and the 3D imaging algorithm was deduced based on the 2D imaging algorithm.The 3D model was designed to verify the imaging resolution and design the sparse array.The Point Spread Function(PSF)was introduced to evaluate th e advantages and disadvantages of the array,and the sparse array imaging was compared with the full array image analysis.To sum up,by introducing the theory of equivalent center,this paper simplifies the full array antenna into a sparse array,evaluate s the effectiveness of the sparse array through PSF,deduces an improved three-dimensional millimeter wave imaging algorithm,designs a millimeter wave imaging system,and at the end of this paper,measures and images models such as fruit knife and metal pistol.