Research On Image Recovery Of Objects After Scattering Medium Based On Speckle Correlation

When light beam propagates through scattering media such as smoke and biological tissues,it will produce strong scattering phenomenon,resulting in disordered optical speckles,which makes it difficult for traditional optical systems to directly detect targets covered by scattering media.Therefore,achieving image restoration through scattering media has become a hot issue in the field of optical imaging.In view of this hot issue,speckle autocorrelation,bispectrum analysis and deconvolution techniques are used to achieve image restoration through scattering media respectively.On the basis of deconvolution method,many applications of scattering imaging are realized.Starting from the concept of optical speckle,the phenomenon of multiple scattering is analyzed.Based on the statistical characteristics of optical speckle,a mathematical model of speckle size is constructed.Optical memory effect,the theoretical basis of scattering imaging restoration,is studied in detail,and its existence is verified by experiments.Based on the optical memory effect of scattering medium,the principle and method of speckle autocorrelation imaging are studied from the aspects of convolution model,background term analysis and phase recovery algorithm.The simulation and experiment show that the method can reconstruct the target after scattering medium,but the phase recovery algorithm has some shortcomings such as multiple iterations and random reconstruction results.Based on the bispectrum analysis principle,the bispectrum analysis scattering imaging recovery technology is studied from the aspects of phase extraction method and mathematical processing.The simulation results show that the technology does not need iteration and the reconstruction result is unique,but it also has the disadvantages of slow reconstruction speed and unable to obtain the PSF information of the scattering system.Therefore,the scattering imaging system in the range of optical memory effect can be regarded as a linear system.A variety of deconvolution algorithms are used to study the deconvolution scattering imaging technology.The simulation and experimental results show that the technology does not need iteration and the reconstruction effect is good.Furthermore,depth resolution,point spread function calculation and moving target tracking and reconstruction after scattering medium are realized.Aiming at the problem of small range of single memory effect,an independent method for obtaining speckles corresponding to different regions of large field of view object is proposed.The restoration effect is clearer than the traditional method of decorrelation of point spread function in different regions.Aiming at the problem that multi-spectral target is generated by projector directly,which results in serious pixelization of restoration effect,a method of multi-spectral target generation is proposed.Experiments show that this method is better than traditional method of direct projection of multi-spectral target,and is not limited by the resolution of projector and target zooming.