Research On Object Reconstruction And Noise Reduction Based On Iterative Computation For Ghost Imaging

Correlated imaging,as an emerging imaging technology in the last twenty years,is commonly referred to Ghost Imaging(GI),also known as two-photon imaging.Different from the traditional imaging technology which should access to the object's spatial information directly,GI obtain a reconstructed image by means of two sets of correlated light intensity information.This imaging technique separates the detecting and imaging,and facilitates the combination with other optical imaging systems.It has the advantages that traditional imaging methods do not have,and has broad prospects in scientific research and practical application.The result of GI is obtained by calculating the data of the object arm and the reference arm,so we can analyze the imaging algorithms in computational aspect.In this paper,we mainly analyze the principle and algorithm of GI,propose an improved imaging method,and analyze the influence of speckle size on imaging method.The main works as follows:(1)Combining Pseudo-inverse Ghost Imaging(PGI)with iterative denoising of ghost imaging,a Pseudo-inverse Iterative method was proposed for object reconstruction of Ghost Imaging(PIGI).The advantages of this method are illustrated theoretically and the simulation experiments are carried out.The experiment results show that the pseudo-inverse iterative method is about 1.0dB and 3.1dB higher than PGI and Differential Ghost Imaging(DGI)respectively in the Peak Signal to Noise Ratio(PSNR),and it's Correlation Coefficient(CC)and visual effects are also improved compared with PGI and DGI.(2)The Compressive Sensing(CS)theory is introduced.We applied the Orthogonal Matching Pursuit(OMP)and the Basis Pursuit(BP)algorithm to GI,and carried out the simulation experiments.Aiming at the fact that the actual data collected by the bucket detector does not approximate the true value,the iterative operation is applied to the data processing to obtain the value approaching the actual situation,and then the data obtained is reconstructed by the CS algorithms.The improved system can reconstruct the original image more accurately than the previous unprocessed data system under the same measurement.(3)Based on the mathematical model of speckle,the influence of the average speckle size on several GI methods is analyzed by simulation experiments.The results show that the PSNR of PIGI and PGI increase rapidly with the increase of the average speckle size,and the PSNR of CGI increase slower than that of the former method.In addition,the effect of the two-arm error on the three imaging methods is analyzed.The experiment results show that the three methods are sensitive to the error of the two arms.Therefore,the three methods above can be used in the error-free or single arm ghost imaging system.