Study Of Adaptive Optics High-speed And High-precision Wavefront Reconstruction Algorithm

In recent years,with the application fields of adaptive optics constantly expanding,the wavefront reconstruction requirements for precision and speed become higher and higher.Because of the increase of sensing subaperture number and the diversity of pupil shapes(such as circular pupil,square pupil and complicate pupil with local disconnected area),doing further researches in reconstruction algorithm and optimizing algorithm for specific applications not only have become the effective approach to improve the precision and speed of wavefront reconstruction,but also have great significance in improving AO system correction effect and bandwidth.In this paper,the traditional wavefront reconstruction algorithms are studied in depth and optimized.A dividing zonal algorithm is proposed in order to solve the problem that traditional zonal algorithm is too slow when solving large amount of reconstruction points.What's more,zonal algorithm and modal algorithm are used in a serial way to deal with the problem that the precision of traditional modal algorithm is low when reconstructing wavefront with high spatial frequency.Firstly,traditional zonal algorithm is introduced and its limitations are analyzed.And then,focused on the computing efficiency of zonal algorithm,a high-speed and high-precision zonal wavefront reconstruction algorithm based on zone dividing is proposed.In this algorithm,the calculation scale is limited by means of dividing wavefront reconstruction so that the algorithm efficiency can be guaranteed.After reconstruction,least squares method is used to calculate the wavefront piston on each block and the whole wavefront is got by subwavefront stitching and edge smoothing.The simulation results show that,while the reconstruction precision is guaranteed,this algorithm can greatly improve the computing speed of zonal algorithm used in reconstructing large amount of reconstruction points.Secondly,traditional modal algorithm is introduced and a modal-zonal hybrid wavefront reconstruction algorithm,where zonal wavefront reconstruction algorithm is introduced to reconstruct the remaining wavefront as a supplementary to modal reconstruction,is proposed according to the problems occurred during modal algorithm is used.This new algorithm can avoid low solving efficiency caused by excessive amounts of mode.Besides,it retain the advantages of modal algorithm that mode coefficients can be used to analyze the relative amplitude of different spatial frequency components of distorted wavefront and its reconstruction precision is guaranteed depending on the feature that zonal algorithm is sensitive to wavefront with high spatial frequency.The simulation results show that the reconstruction precision of this algorithm is far higher than that of modal algorithm used alone.Finally,using commercial wavefront sensor HASO3 as the standard,an experimental system is designed and built to test the performance of the zone dividing-based high-speed and high-precision zonal wavefront reconstruction algorithm.Utilizing the system,the reconstruction precision of the proposed algorithm under different shapes of pupils is determined.The experimental results show that the reconstruction precision of the proposed algorithm is fairly high,because the average reconstruction error of the proposed algorithm is no higher than 1%wavelength(comparing with the reconstruction results of HASO,the reconstruction precisions under circular pupil and square pupil are 0.0018 ? and 0.0029 ?respectively).