Wavefront restoration method based on Shack-Hartmann wavefront sensor

Abstract

The invention discloses a wavefront restoration method based on a Shack-Hartmann wavefront sensor. According to the method, a correlation function of theoretical far-field light intensity distributionand actually-measured far-field light intensity distribution is used as a target function, and the wavefront is restored through a modulation-optimized random parallel gradient descent method. According to the invention, the far-field light spot intensity distribution is used as the input of the algorithm, the information in the sub-apertures is fully utilized, the dependence of the Shack-Hartmann wavefront sensor on the high-density sub-apertures is effectively reduced, the wavefront restoration precision is improved, and the modulation factor is used for the spatial and temporal modulationof the Zernike coefficient disturbance quantity, so that the algorithm can be prevented from falling into local optimum, and the convergence of the algorithm is accelerated. Compared with a traditional Shack-Hartmann wavefront sensing algorithm, wavefront restoration can be completed with higher precision under the same sub-aperture condition, wavefront restoration can be completed with fewer sub-apertures under the condition of the same restoration precision, and a new technical approach is provided for the fields of weak-light and high-precision wavefront detection and the like.

Description

technical field [0001] The invention belongs to the technical field of wavefront detection, in particular to a wavefront restoration method based on a Shack-Hartmann wavefront sensor. Background technique [0002] Phase measurement has always been one of the research hotspots in the field of optics. It is involved in many fields such as astronomical observation, optical detection, medical imaging, and adaptive optics. The existing mainstream phase measurement methods are mainly divided into three categories: interferometry, direct measurement method, and indirect measurement method based on intensity distribution. Each type of method has its unique advantages and is applied to different occasions. Among them, the Shaker-Hartmann wavefront sensor based on slope measurement has been widely used in various fields due to its advantages of fast measurement speed and high precision. [0003] The Shack-Hartmann wavefront sensor mainly divides and samples the wavefront through the ...

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Problems solved by technology

However, the wavefront information extracted by this method is limited, and there is an inherent contradiction between the measurement accuracy of the Shack-Hartmann wavefront sensor and the spatial sampling rate, which limits the measurement performance of the Shack-Hartmann wavefront sensor

[0004] How to improve the detection performance of the Shack-Hartmann wavefront sensor under low spatial sampling has always been one of the research hotspots. Some researchers have proposed to use GS algorithm, phase difference method and other methods to restore the wavefront according to the spot intensity distribution, and improve the The accuracy of wavefront restoration and the order of Zernike mode aberration reduce the number of sub-apertures, but this kind of algorithm is easy to fall into the local optimal solution, and it is difficult to effectively restore the wavefront when the incident wavefront distortion is large and the signal-to-noise ratio of the detection signal is low. forward

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