Influence of coupling coefficient on sparseness of slope response matrix and iterative matrix

Cheng, Sen; Chen, Shanqiu; Dong, Lizhi; Liu, Wenjin; Wang, Shuai; Yang, Ping; Ao, Mingwu; Xu, Bing

doi:10.7498/aps.63.074206

Cited by 2 publications

(1 citation statement)

References 9 publications

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“…Adaptive optics (AO) is a technique that was conceived to compensate in real time for the phase perturbations introduced by atmospheric turbulence. [1,2] At present, AO systems have been used in many fields, such as improving laser beam quality, [3][4][5][6][7][8] correcting the errors in astro-observation brought by atmospheric disturbances, [9][10][11][12] researching on ocular aberration, etc. The standard and most used wavefront control algorithm for AO system is a direct gradient wavefront control algorithm, which is based on a matrix-vector multiplication of the relational matrix from deformable mirror (DM) to Hartmann wavefront sensor (WFS) and the slope vector measured by WFS.…”

Section: Introductionmentioning

confidence: 99%

Comparison between iterative wavefront control algorithm and direct gradient wavefront control algorithm for adaptive optics system

et al. 2015

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Among all kinds of wavefront control algorithms in adaptive optics systems, the direct gradient wavefront control algorithm is the most widespread and common method. This control algorithm obtains the actuator voltages directly from wavefront slopes through pre-measuring the relational matrix between deformable mirror actuators and Hartmann wavefront sensor with perfect real-time characteristic and stability. However, with increasing the number of sub-apertures in wavefront sensor and deformable mirror actuators of adaptive optics systems, the matrix operation in direct gradient algorithm takes too much time, which becomes a major factor influencing control effect of adaptive optics systems. In this paper we apply an iterative wavefront control algorithm to high-resolution adaptive optics systems, in which the voltages of each actuator are obtained through iteration arithmetic, which gains great advantage in calculation and storage. For AO system with thousands of actuators, the computational complexity estimate is about O(n2) ∼ O(n3) in direct gradient wavefront control algorithm, while the computational complexity estimate in iterative wavefront control algorithm is about O(n) ∼ (O(n)3/2), in which n is the number of actuators of AO system. And the more the numbers of sub-apertures and deformable mirror actuators, the more significant advantage the iterative wavefront control algorithm exhibits.

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Section: Introductionmentioning

confidence: 99%

Comparison between iterative wavefront control algorithm and direct gradient wavefront control algorithm for adaptive optics system

et al. 2015

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Influence of Gaussian function index of deformable mirror on iterative algorithm adaptive optical system

Cheng¹,

Chen²,

Dong³

et al. 2015

Acta Phys. Sin.

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Among all kinds of wavefront reconstruction algorithms in adaptive optical systems, the standard and mostly used algorithm is the direct gradient wavefront reconstruction algorithm. As the number of sub-apertures in Shack-Hartmann wavefront sensor and the actuators for deformable mirror increases, the reconstruction matrix in direct gradient wavefront reconstruction algorithm takes too much space and the number of multiplication in the algorithm increases sharply. So, the iterative algorithm is adopted in wavefront reconstruction for the high-resolution adaptive optical system. The number of multiplication and the required space of the iterative algorithm are directly related to the sparseness of both iterative matrix and slope response matrix. In an adaptive optical system, the sparseness of these two matrixes is connected with the system parameters. Therefore, it is necessary to study how to choose the proper parameters for an adaptive optical system when it uses iterative wavefront reconstruction algorithm. In this paper, the sparseness of slope response matrix and iterative matrix are analyzed based on a 613-actuator adaptive optical system. The influence of the Gaussian function index of deformable mirror on the sparsenesses of slope response matrix, iterative matrix, stability and correction qualities of the adaptive optical system are also studied under the condition of constant actuator spacing and coupling coefficient. A larger Gaussian function index results in a lower sparseness of the slope response matrix and the iterative matrix. Too large or too small a Gaussian function index will degrade the stability and the correction quality of an adaptive optical system. Finally, the optimal range of the Gaussian function index is provided by balancing the sparseness of slope response matrix, the correction quality, and the stability of the adaptive optical system.

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Influence of coupling coefficient on sparseness of slope response matrix and iterative matrix

Cited by 2 publications

References 9 publications

Comparison between iterative wavefront control algorithm and direct gradient wavefront control algorithm for adaptive optics system

Comparison between iterative wavefront control algorithm and direct gradient wavefront control algorithm for adaptive optics system

Influence of Gaussian function index of deformable mirror on iterative algorithm adaptive optical system

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