The Study Of The Adaptive Wavefront Control Technique Based On The Optimization Of The Image-quality-metric Function

The image sharpening adaptive optics system (AOS) is an adaptive wave-front control system based on the optimization of the image-quality-metric function. It is expected that the stochastic parallel gradient descent (SPGD) algorithm improve the convergence speed of traditional image sharpening adaptive optics systems and make it possible to realize the real time wave-front distortion correction. Firstly, the constitution of an image sharpening adaptive optics system, the principle of images sharpening, and the definitions of several image-quality-metric functions are discussed in this thesis. Secondly, the principle of the SPGD algorithm is introduced and the iterative formula is presented. Then the convergence characteristic and some optimization technique of the algorithm are discussed, and the architecture of an adaptive optics system based on SPGD control algorithm is addressed. At last, an image sharpening adaptive optics system was set up for the first time in China. Then the closed-loop experiments were implemented and the wavefront correction of the static aberration introduced by the deformable mirror was realized. Results of experiments indicate that the SPGD algorithm is robust and convergent. The thesis offers a foundation to the study of the practicality of the wavefront control technique based on the SPGD.