A Wavefront Detection Method Based on Cross Iterative Autofocus

Abstract

The invention discloses a wavefront detection method based on cross iterative automatic focusing. The method uses the analytical gradient formula to optimize the defocus distance to realize the automatic determination of the defocus position, and uses the cross iteration method to overcome the inaccurate determination of the defocus position caused by the inaccuracy of the wavefront and the inaccurate determination of the defocus position caused by the uncertainty of the defocus position. For the problem of inaccurate wavefront reconstruction, by optimizing the defocus distance, wavefront amplitude and phase for the same objective function, the accurate reconstruction of defocus position and wavefront error is realized. The invention realizes accurate determination of large defocus errors of multiple images, and realizes accurate reconstruction of wavefront under the condition of uncertain defocus positions without additional construction of an objective function.

Description

technical field [0001] The invention relates to the technical field of optical measurement and imaging, in particular to a wavefront detection method based on cross iterative autofocus. Background technique [0002] Computational imaging has greatly changed the WYSIWYG model of traditional imaging. Through computer post-processing, it overcomes the imperfect imaging of traditional imaging systems and reduces the size and weight of imaging systems. Coherent diffraction imaging is an implementation of computational imaging. Coherent diffraction imaging is a quantitative phase imaging method based on an iterative method; the image sensor is used to collect diffraction images on the focal plane or the defocused plane; the amplitude of the wavefront or image to be measured is obtained by repeated iterative calculations using Fourier transform and inverse Fourier transform and phase; the processing of the amplitude or support domain in the iterative process is similar to mapping ...

AI Technical Summary

Problems solved by technology

[0003] However, the axial phase difference method is very sensitive to the determination of the defocus position, especially the relative position between different defocus surfaces. Generally, a high-precision precision guide rail moving image sensor is selected to collect the diffraction spot, resulting in a complete set of The price of the device is very expensive, and in some applications, such as in-position detection, it is difficult to place precision guide rails, which makes it very difficult to determine the out-of-focus position

Images