Research On Aberration Correction Technique Of Quadric Surface Conformal Dome Based On Computational Imaging

The essential difference between conformal optical system and traditional optical system is that the former gives priority to the aerodynamic performance of the conformal dome,not the imaging quality of the system.The key to the design of the conformal dome and its rear optical system is to correct the dynamic aberration introduced by the conformal dome.Traditional aberration correction methods,including fixed corrector and dynamic aberration corrector,have their limitations.Therefore,it is of profound significance to develop aberration correction technique in a way.As an emerging technique,computational imaging combines imaging optics with digital signal processing technique,imaging performance has been greatly improved compared with the traditional optical system.Wavefront coding,which is one of the most classical techniques in computational imaging,is able to expand the system’s focal depth without reducing the flux and imagin g resolution of the system.Obviously,it can also effectively suppress the aberration caused by the disfocusing,so as to provide a new idea for aberration correction.This paper focuses on the aberration correction technique based on computational imaging,mainly researches on the aberration characteristics of conicoidal conformal dome and the sensitivity of wavefront coding to the off-axis aberration,and puts forward to apply wavefront coding to the design of conicoidal conformal optical system,suppressing the dynamic aberration,improving the performance of optical imaging system,so as to obtaining the target image with high resolution and good image quality.The research can provide theoretical basis and technical support for the design and the aberration correction of conformal optical system.The main contents of this paper include the following three parts.(1)Researche on the aberration characteristics of conicoidal conformal dome.The initial structures of ellipsoidal,parabolic and hyperbolic co nformal domes with an fineness ratio of 1 are established respectively,and the dynamic aberration introduced by the conformal dome in the scanning process is revealed.Then,based on the Zenik aberration theory,the astigmatism and coma of the conicoidal conformal dome with different fineness ratios are studied.(2)Researche on the sensitivity of wavefront coding to off-axis aberration.Based on the analytical expression of the optical transfer function,the sensitivity of the optical system with a cubic phase mask to the off-axis aberration,primary astigmatism and primary coma,is analyzed in detail.In addition,two optimization methods of phase mask parameters are introduced,namely,the optimization method based on PSF consistency and the optimization method based on Fisher information theory.(3)Design of conicoidal conformal optical system based on wavefront coding.The wavefront coding technique is applied to the conformal optical system for aberration correction,and two typical design examples are given to demonstrate the ability of the wavefront coding technique to correct the asymmetric aberration in the conformal optical system.The dynamic aberration of the conformal optical system is corrected by adding a cubic phase mask to the conformal optical system composed of conformal dome,fixed corrector and double reverse system.According to the parameters of the optical system and the characteristics of the infrared optical system,the design of the optical system is completed and the image simula tion is carried out.It is proved that the wavefront coding technique can effectively correct the dynamic aberration of the conformal dome.