Research On Optimization Of Millimeter Wave Holographic Imaging Algorithm

With the escalation of terrorism and regional armed conflicts,the public security problems in crowded places of activities are increasingly concerned by countries around the world.Array imaging system using active millimeter wave technology is an effective means to deal with such security problems.X-ray machines are suspected of having an effect on people's physical health.The array imaging system working in millimeter-wave band can penetrate thin layer media to achieve high-precision imaging of concealed objects without affecting the health of the body,and non-metallic objects with small reflectivity can also achieve good imaging effect in millimeter-wave band.Millimeter wave band has higher resolution and better imaging effect,but it requires more array element number and smaller array element spacing.The range resolution of active millimeter-wave array is not high due to the limitation of array bandwidth.These three factors put forward quite high requirements on the manufacturing cost of millimeter-wave array.The imaging technology based on MIMO array and target reconstruction technology based on phase information are important methods to reduce the limitation.This paper studies the imaging inversion of millimeter wave planar array based on the holographic reconstruction of the measured target in millimeter wave band.The characteristics of millimeter-wave in the near field of security inspection are studied,and the narrowband 2d and wideband 3D imaging methods are analyzed.Aiming at the problem that SISO array elements are difficult to be arranged in millimeter wave band,the wavenumerative domain imaging algorithm of MIMO array is analyzed.However,the algorithm requires multiple Stolt interpolation and has a large computational load.Therefore,an imaging algorithm with low computational complexity and low impact effect is studied by combining the method of distance compensation.In the case of large data volume,the algorithm can reduce the operation time by 80% compared with wave-number domain algorithm.Using MIMO experimental data for analysis,in view of the millimeter wave array distance resolution is limited by the radar bandwidth about the problem of the research,through the recovery phase information of the way to reduce the limitation of the radar range resolution,based on convolution is studied under the condition of the broadband phase precision higher holographic imaging algorithm,analyses the theory of interference in the application of the holographic imaging.The experimental results and simulation show that the improved algorithm is implementable and achieves the desired effect.