利用88单元变形镜及电荷耦合器件成像器件,以扩展目标为校正对象,建立了带有噪声的无波前探测自适应光学系统模型。在噪声情况下,验证了扩展目标成像时掩模探测器信号和波前相位的平均梯度平方和之间存在线性关系。将基于此线性关系的算法作为无波前探测自适应光学系统的控制算法,通过仿真,检验了模型式无波前探测自适应光学系统在噪声情况下对扩展目标成像的校正能力。结果表明,相同湍流条件、不同信噪比下的校正效果接近。按照湍流条件从小到大的顺序,与信噪比为20 dB的结果相比,信噪比为5 dB时校正后的平均均方根相对误差分别为3.71%,2.94%和2.42%,说明基于该线性关系的模型控制算法具有较强的抗噪能力。

The wavefront sensorless adaptive optics (WFSless AO) system under noise is established using an 88-element deformable mirror and a charge coupled device imaging device and with an extended object as a correction object. The linear relationship between the masked detector signal and the mean-square wavefront gradient of the extended object imaging under noise is verified. The algorithm based on this linear relationship is used as the control algorithm of the WFSless AO system. The simulation experiment is carried out to check the correction ability of the model-based WFSless AO system for extended object imaging under noise. The results show that the correction effects are very close under the same turbulence condition but different signal-to-noise ratios. According to the order of turbulence conditions from small to large, the averaged root mean square relative errors after correction under a signal-to-noise ratio of 5 dB are 3.71%, 2.94% and 2.42%, respectively, if compared with the results under a signal-to-noise ratio of 20 dB. The above results indicate that the model-based control algorithm with this linear relationship has a relatively good anti-noise capability.