基于正交模式扰动梯度下降算法的自适应光学控制技术

Adaptive Optics Control Technique Based on Orthogonal Mode Perturbance Gradient Descent Algorithm

针对无波前探测自适应光学提出一种基于正交模式扰动梯度下降(OP_GD)算法的控制技术。通过与串行扰动梯度下降算法和随机并行梯度下降(SPGD)算法对比,分析了该算法的可行性和收敛速度。在此基础上,采用液晶空间光调制器(LC_SLM)作为波前校正器,建立了基于该控制技术的自适应光学实验装置,实验研究了算法的收敛特性。实验结果表明,正交模式扰动梯度下降算法具有很好的全局收敛性,其收敛速度和SPGD算法相当。但是与SPGD算法相比,正交模式扰动梯度下降算法无需设计伪随机序列发生器,因此硬件实现更加容易。

For wavefront sensorless adaptive optics systems, a control technique based on the orthogonal mode perturbance gradient descent （OP GD） algorithm is proposed. The feasibility and convergence speed of this method are analyzed comparing with the serial gradient descent algorithm and stochastic parallel gradient descent （SPGD） algorithm. After that, an adaptive optics setup with liquid crystal spatial light modulator （LC_SLM） is set up, and the convergence characteristic is analyzed experimentally. The results show that this algorithm has a good global convergence characteristic and almost the same convergence speed as SPGD algorithm. However, compared with SPGD algorithm, the orthogonal mode perturbance gradient descent algorithm is easier to perform with hardware because the pseudo-random sequence generator is unnecessary.