High resolution imaging of phase-distorted extended object using SPGD algorithm and deformable mirror

Abstract

The conventional adaptive optics (AO) technique based on phase conjugate principle requires the information about a reference wave front that corresponds to the undistorted image when it is applied to extended source image correction. The AO technique based on the image function appears more promising than the conventional AO for this application. The success of this technique depends on an appropriate image quality criterion and a suitable control algorithm. We tried to find a convenient image performance metric not from additional optics elements, but only from the distorted image which is a gray level image. Simulation results showed the variance function of gray level presents more potential than other ways, such as ways based on the information about the gray level gradient of each pixel. Based on SPGD algorithm, an AO system was simulated with a 61-element deformable mirror and the above resultant image quality criterion. The correction capability of the AO system was investigated through different images and different level aberrations. Numerical simulation results verified the performance metric we used is effective. The system can correct different level disturbed images successfully when parameters of the algorithm were appropriate for static distorted wave-fronts。

Location-grouping algorithm based on limited actuators deformable mirror for high precision wavefront aberration correction in adaptive optics system

“…At two levels of wavefront correction based on the SA (Simulated annealing) algorithm and the SPGD (stochastic parallel gradient descent) algorithm [4], the control elements of wavefront corrector of deformable mirrors are subdivided into four parts depending the location. First of all, with the combination of SA and SPGD algorithm, the entire wavefront is optimized.…”