Study On Computational Ghost Imaging Based On Pseudothermal Light Source With Optical Fiber Array In Moving Platform Condition

Ghost imaging,known as correlated imaging,is one of the frontier technologies in the field of optics.It is a great breakthrough and progress in traditional imaging technology.Especially for the need to reconstruct a target with only one single point detector,Computational Ghost Imaging(CGI)significantly simplifies the system structure and expands the research direction of ghost imaging.Faced with application requirements of target-oriented remote sensing detection,the CGI uses fiber laser coherent synthesis technology for reference.It is combined with the unique technical advantages of laser threedimensional imaging.Besides,It is under motion platform and motion compensation that can improve the quality of imaging.This research on performance analysis of computational ghost imaging system can provide theoretical and methodological support for twodimensional and three-dimensional reconstruction of target.In one word,it is of great significance for the application of the CGI system basing pseudothermal light source with optical fiber array on motion platform in remote sensing detection.In this thesis,it introduces the basic principle of CGI and calculation method of CGI reference light field,and summaries the principles of STC,DGI and OMP imaging algorithms.Besides,based on pseudothermal light source with optical fiber array,the performance of CGI system with low pixel APD array is further studied.Firstly,the optical field characteristics of pseudo-thermal light source of fiber array are analyzed,a receiving system based on low-pixel APD array detector is designed,and the imaging performance of the system is evaluated.Then,based on the same ghost imaging algorithm,compared with the traditional single-point detection CGI system,the APD array detector is used to reconstruct the target image.As a result,it has greatly decreased the demand of sampling time,and the calculation time consumption with parallel processing has been reduced significantly.Since the high-speed time-varying speckle irradiation can be realized by the light source,the imaging quality under the same imaging frame frequency and sampling times can be markedly improved.Based on the ideal motion platform model,this thesis has analyzed the effects of the platform motion on the reconstruction of two-dimensional space images.In the meanwhile,the platform motion compensation method based on the "calculation correction" of the reference light field is studied,and the 2D and 3D image reconstruction process under the motion platform is given.With the same ghost imaging conditions,for CGI system basing optical fiber array,the negative influence of platform motion is significantly reduced.Besides,the quality and rate of image reconstruction applied with DGI algorithm are better than that of the OMP algorithm in traditional CGI system.The final simulation results show that,the motion compensation method based on reference light field is feasible and effective.Utilizing fiber array,it can realize high-speed speckle field projection and high-power beam transmission through high-speed electro-optical phase modulator.The low-pixel APD array detector is used to receive the signal light,and the improvement of imaging rate in CGI system can further decrease the "sensitivity" of the moving platform speed.The image blurring caused by the platform motion can be effectively corrected utilizing "computational correction" of reference light field.However,non-uniform motion of the moving platform,change of flight altitude and low reception signal-to-noise ratio are not ideal conditions in the practical application,which need to be further targeted motion compensation and imaging methods.