Niu Saisai, Shen Jianxin, Liang Chun, Zhang Yunhai, Li Bangming
College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
Appl Opt. 2011 Aug 1;50(22):4365-75. doi: 10.1364/AO.50.004365.
Based on the dynamic characteristics of human eye aberration, a microadaptive optics retina imaging system set is established for real-time wavefront measurement and correction. This paper analyzes the working principles of a 127-unit Hartmann-Shack wavefront sensor and a 37-channel micromachine membrane deformable mirror adopted in the system. The proposed system achieves wavefront reconstruction through the adaptive centroid detection method and the mode reconstruction algorithm of Zernike polynomials, so that human eye aberration can be measured accurately. Meanwhile, according to the adaptive optics aberration correction control model, a closed-loop iterative aberration correction algorithm based on Smith control is presented to realize efficient and real-time correction of human eye aberration with different characteristics, and characteristics of the time domain of the system are also optimized. According to the experiment results tested on a USAF 1951 standard resolution target and a living human retina (subject ZHY), the resolution of the system can reach 3.6 LP/mm, and the human eye wavefront aberration of 0.728λ (λ=785 nm) can be corrected to 0.081λ in root mean square (RMS) so as to achieve the diffraction limit (Strehl ratio is 0.866), then high-resolution retina images are obtained.
基于人眼像差的动态特性，搭建了一套用于实时波前测量与校正的微自适应光学视网膜成像系统。本文分析了该系统中采用的127单元哈特曼-夏克波前传感器和37通道微机电薄膜变形镜的工作原理。所提系统通过自适应质心检测方法和泽尼克多项式的模式重建算法实现波前重建，从而能够精确测量人眼像差。同时，根据自适应光学像差校正控制模型，提出了一种基于史密斯控制的闭环迭代像差校正算法，以实现对不同特性人眼像差的高效实时校正，并对系统的时域特性进行了优化。根据在美国空军1951标准分辨率靶标和活体人眼视网膜（受试者ZHY）上的实验测试结果，该系统的分辨率可达3.6 LP/mm，人眼波前像差0.728λ（λ = 785 nm）的均方根（RMS）可校正至0.081λ，从而达到衍射极限（斯特列尔比为0.866），进而获得高分辨率的视网膜图像。
