成像系统噪声对无波前探测自适应光学校正效果的影响  

Effects of Imaging System Noise on the Correction Capability of Adaptive Optics without a Wavefront Sensor

作　　者：杨慧珍[1] 李新阳[2] 

机构地区：[1]淮海工学院电子工程学院,江苏连云港222005 [2]中国科学院光电技术研究所,四川成都610029

出　　处：《中国激光》2010年第10期2520-2525,共6页Chinese Journal of Lasers

基　　金：中国科学院自适应光学重点实验室(LAOF201004);淮海工学院引进人才科研启动基金(KQ09035)资助课题

摘　　要：大气湍流和成像系统噪声的存在使得观测的扩展目标图像退化、扭曲,进而无法辨认其细节。目前,常采用自适应光学技术实时去除由于大气湍流带来的像差。以61单元变形镜作为校正器,随机并行梯度下降算法作为无波前探测自适应光学系统的控制算法,扩展目标图像灰度值的方差函数作为控制算法优化的性能指标函数,建立无波前探测自适应光学系统仿真模型,分析成像系统噪声对无波前探测自适应光学校正效果的影响。结果表明,当像差较小且图像信噪比大于20 dB时,自适应光学技术的校正效果几乎不受影响;但随着信噪比的减小,校正效果对比无噪声时明显变差。相同的信噪比条件下,像差越大,成像效果受噪声的影响越大。The atmosphere turbulence and imaging system noise can degrade and distort the imaging of the extended object.Adaptive optics technology is usually used to mitigate the wave-front aberrations caused by the atmosphere turbulence.An adaptive optics（AO） system with stochastic parallel gradient descent（SPGD） algorithm and a 61-element deformable mirror is simulated to restore the image of a turbulence-degraded extended object and the gray level variance function is used as the optimized object by controlling algorithm.Based on the above simulation mode,effects of imaging system noise on the correction capability of adaptive optics are discussed.The results show that the correct capability is not affected when the signal noise ratio（SNR） is bigger than 20 dB for relative small turbulence,while the correction capability becomes worse obviously as the SNR decreases.Under the same SNR,the stronger the turbulence,the bigger the effect on the correction capability.

关 键 词：大气光学 扩展目标 自适应光学系统 图像质量评价 随机并行梯度下降 

分 类 号：TP273.2[自动化与计算机技术—检测技术与自动化装置]