Research On Precision Measurement Technology Of Optical System Distortion

Distortion is one of the aberrations that characterize the imaging infidelity of an optical system,essentially the geometric misalignment of optical information.The large field of view optical system is difficult to control distortion,and the effect of distortion can be reduced by image correction.In the fields of atomic and molecular physics,solid physics,biomedicine,applied optics,and other experimental instruments such as laser systems and spectrometers,distortion correction techniques are widely applied.The acquisition of reliable calibration results requires an accurate measurement of optical system distortion.The accuracy of the distortion measurement directly determines the accuracy of the correction.At present,the distortion measurement accuracy of conventional optical systems is mostly 10^-3,which cannot meet the measurement requirements of optical instruments with high requirements.Therefore,it is necessary to carry out research on distortion measurement with high precision of 10^-4 or higher.This paper focuses on the measurement of distortion in high-precision optical systems.The details are as follows.Firstly,the causes of distortion are analyzed theoretically,and the measurement principles of different distortion measurement methods are demonstrated.Combined with the requirements of high-precision measurement,the research on high-precision distortion measurement is finally carried out based on the principle of rotation angle.Secondly,the measurement error analysis is carried out based on the principle of rotation angle that the main error sources of angle measurement error and length measurement error are obtained.Meanwhile,the detailed error distribution is completed based on the index requirement of 0.01%.The experimental module selected by the algorithm optimization guarantees the error distribution to obtain the experimental data stably and accurately.Thirdly,the detailed design of high-precision distortion measuring instrument is carried out based on error distribution.The hardware design and algorithm optimization scheme based on error optimization are elaborated in detail,including the precise angle measurement scheme based on high-precision turntable combined with high-order compensation algorithm of eccentricity error.An optical system fixed focus and focal length measurement scheme based on a precision focusing stage combined with a precision fixed focus/focusing algorithm and an image height measurement scheme based on a back-illuminated image sensor and a sub-pixel-level centroid extraction algorithm.In the end,the installation and adjustment of the high-precision distortion measuring instrument are completed,and a large number of experimental studies are carried out.The data show that the error distribution in the early stage of the system is reasonable,the model is correct,and the optimized design scheme for the error source in the design is effective.After the algorithm optimization,the turntable Angle accuracy is 2″,the fixed focus accuracy is 1.25μm,and the star coordinate extraction accuracy is 0.036 pixels.The final relative distortion measurement accuracy is 0.009%,which is better than the design index requirement.The research results can be applied to atomic and molecular physics,solid state physics,biomedicine,applied optics and other scientific research fields.