离焦量误差对相位差法波前重构的影响  

The Effect of Uncertainty in Defocus Distance on the Wave-front Reconstruction with the Phase-diversity Algorithm

作　　者：杨磊[1] 刘忠[1] 金振宇[1] 于学刚[1] 

机构地区：[1]中国科学院国家天文台云南天文台,云南昆明650011

出　　处：《天文研究与技术》2009年第1期43-50,共8页Astronomical Research & Technology

基　　金：国家自然科学基金天文联合基金(10778636);国家自然科学基金重点项目(10533040)资助

摘　　要：相位差法波前探测是利用焦面和已知像差函数及像差尺度的离焦位置上同时采集的一对短曝光图像,通过最优化方法使代价函数最小化,从而得到目标和波前相位估计值的波前探测方法。本文通过计算机模拟了像差函数为离焦像差的情况下,经相位差法波前探测成像系统后在焦面和离焦面上采集得到的图像强度分布,采用有限内存拟牛顿法(LFBGS)对模拟图像进行数值求解,实现了波前相位的重构和对面源目标的重建;由于在实际应用中测量误差和机械加工带来的离焦量偏差是不可避免的,因此在模拟实验中就离焦量尺度不精确的情况进行了分析。The phase-diversity algorithm is a wave-front sensing technique for obtaining estimates of both the precise object image and the distribution of wave fronts. It involves the simultaneous collection of a pair of short-exposure images： one is the typical focal-plane image and the other is the aberrated image on a defocused plane （with known aberration functions and aberration scales there）. With these images, one can use the optimization theory to minimize the cost function to recover the precise image of object as well as the phase aberration. In this paper, based on the phase-diversity algorithm, we numerically simulate the intensity distributions of the focal-plane image and aberrated image under the circumstances that the uncertainty of the aberration function is due to defocus. We further implement the wave-front reconstruction and image recovery of the simulated extended scenes （object） by applying a limited-memory BFGS method to deal with the optimization problem. Owing to the errors in measurement and mechanical manufacturing, the uncertainty in defocus distance is practically inevitable. So in the simulation of this paper, we study and analyze the effect of such an uncertainty on the wave-front reconstruction with the phase-diversity algorithm.

关 键 词：波前重构 图像重建 相位差法波前探测 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]