相位差异法探测波前的误差分析及消除方法

Error Analysis and Eliminate Methods for Wavefront Detection Based on Phase Diversity Algorithm

针对附加像差为离焦模式的相位差异波前探测技术在实际工程应用中遇到的各类误差问题,以探测拼接型望远镜的共相误差为例,通过数值仿真对焦面位置误差、离焦量误差、图像对准误差、曝光延时误差及噪声误差对波前探测精度的影响进行了定量分析。并提出了通过改进相位差异算法进行消除相应误差项的方法,使得波前探测的均方根误差分别由校正前的0.06λ、0.0581λ、0.0754λ、0.0796λ、0.0737λ分别下降为5.8834×10-4λ、6.664×10-4λ、3.5853×10-5λ、6.1837×10-5λ、0.0013λ,且对于各误差项在较大误差范围内,仍可以保持上述相同量级的波前探测精度。结果表明:该方法可以有效地消除误差,大幅度提高波前传感精度,对于相位差异波前探测技术在实际工程中的应用具参考意义。

Aimed at the error problems during practical engineering applications of wavefront detection based on phase diversity method when additional aberration is away from the focus mode, the impacts of these errors on the wavefront detection accuracy have carried on the quantitative analysis by taking the co-phasing of the segmented telescope are analyzed as an example, including focal plane position error, uncertainty of defocus amount, image alignment error, exposure delay and image noise. The method is presented to eliminate these impacts through modifying the phase diversity algorithm, the root mean square errors drop from 0.06λ, 0.0581A, 0.0754λ, 0.0796λ, 0.0737λ down to 5.8834 ×10^-4λ, 6.664 ×10^-4λ, 3.5853 ×10^-5λ, 6.1837 × 10^-5λ, 0.0013λ respectively after correction, and the wavefront detection accuracies are still maintained in the same order of magnitudes as above even when errors are in a quite large range. The results show that the proposed method can effectively eliminate the errors, vastly improve the wavefront detection accuracy and has guiding significance for the usage of phase diversity wavefront detection technology in practical engineering.