利用相位差异技术校准非共光路静态像差

提出了一种用相位差异(PD)技术对自适应光学(AO)系统的非共光路静态像差进行校准的方法。相位差异技术通过采集焦面和离焦面的单帧或多帧短曝光图像来估算波前相位畸变,同时对目标图像进行恢复。在闭环工作条件下,自适应光学系统利用相位差异算法在线检测成像光路的静态像差,并将得到的像差系数转化为变形镜的初始化面形,从而补偿非共光路的静态像差。实验结果表明,校准后的成像质量显著提高,目标半峰全宽降低了约14%,系统残差降低了约72%。成像光路在线检测得到的系统残差与闭环回路实测残差的水平趋于一致,证实了相位差异技术应用于光学检测的能力。该方法具有在无需改变原有自适应光路以及高信噪比条件下便可精确解算系统像差的优点,是大口径光电成像系统较为理想的光学检测技术之一。

Calibration of Non-Common Path Static Aberrations by Using Phase Diversity Technology

A method of calibrating static aberrations in non-common optical path of adaptive optics (AO) system by using phase diversity (PD) techniques is proposed. PD techniques are used to estimate the distorted wavefront phase and recover the object imaging by exploiting the collection of two or more short-exposure optical images, one of which is formed by focusing and others by defocusing. In order to compensate the non-common path error, PD algorithm is used to detect the static aberrations of the imaging optical path online when the AO system is working in close-loop state. Then the result is transformed to the deformable mirror′s initial surface. Experimental results indicate that the image quality is improved obviously after calibration. The value of full-width at half-maximum within the object is reduced by about 14% and the remainder error of the system is reduced by about 72%. The remainder error detected in the imaging optical path is consistent with that of the AO close-loop path, and the ability of the PD techniques is verified in optical detection. The proposed method does not need to change the AO optical path and can accurately figure out the system static aberrations in high signal-to-noise ratio (SNR) conditions, so it can be used as a good mean to detect optical path error in the large aperture telescope.