Research on joint control algorithm for optical path of sparse aperture imaging system

To solve the problem of poor cophasing errors correction in the sparse aperture imaging system, a joint optimal control algorithm for optical path control is proposed. A stochastic parallel gradient descent (SPGD) algorithm is employed to create a joint control system that incorporates multiple piezoelectric ceramics in a sparse aperture imaging system, aiming to optimize imaging definition. The experimental results show that the response curves of different displacements are basically coincident with the expected displacement curves, the response time can be effectively controlled within 0.08 s for different displacements, and the position error can be effectively controlled within ±3 nm. The SPGD joint control system is applied to a three-aperture sparse aperture imaging system for comparison experiment of resolution board imaging. Quantitative evaluation of the images before and after cophasing errors correction is made, resulting in an evaluation value J₁ = 0.54 before correction and J₂ = 0.78 after correction. This demonstrates that the joint control system is efficient in controlling optical path accuracy, correcting cophasing errors, and achieving sub-beam interference imaging.