Research On Off-axis Distortion Correction Axis Calibration System

With continuous development in optical field,integrated optical systems are widely used.These devices usually involve multiple subsystems for transmission and detection of visible or infrared beams.In the past,optical subsystems are independent each other,producing serious alignment and pointing errors.Therefore calibration and correction are necessary before the devices are used.In this paper,a calibration system is designed which is based on an off-axis afocal beam expanding system.Three subsystems are integrated for CCD、PSD detection and 633 nm transmition.After system simulation using Zemax software,distortion was discovered in the detecting subsystem,producing image positioning error and reduced angular resolution.For distortion correcting purposes,the overdetermined equations are established,the least-square method is used for determining the distortion correction parameters.In this way,the image position error is reduced and the resolution is improved.In order to ensure the feasibility of the project,allowable tolerances are determined,and the performance changes of the system at different temperatures are analyzed,the main optical elements are processed and tested.The mechanical structure of the system is designed.Finally,the optical path is built for experiment to verify the main performance indicators of the system.The experimental results show that the RMS errors of the two detection systems are 0.0644 X and 0.0655 λ(λ=633 nm),which are smaller than λ/15,the resolutions are 0.43" and 0.49",which are smaller than 0.5".