Method for automatically extracting center of out-of-focus blurred centering image of aspheric optical element

Abstract

The invention discloses a method for automatically extracting a center of an out-of-focus blurred centering image of an aspheric optical element. The method includes: taking a gray variance definitionevaluation function as a measurement standard, and obtaining a region of interest with the highest definition in a coarse focusing image, namely a region where the center of a cross reticle is located; selecting the image with the highest SMD2 value of the ROI from the odd number of images acquired at equal step pitch; if the value is smaller than a prior threshold value, performing deblurring processing on the optimally focused image by using a trained IRCNN deep learning model or based on an improved dark channel prior algorithm, then obtaining a connected domain of the cross reticle by using adaptive threshold binaryzation and morphological operation, and solving a maximum inscribed circle of the connected domain, the circle center of the inscribed circle being approximate to the center of the cross reticle. According to the invention, the problem that the center of the centering cross reticle image of the aspheric optical element is difficult to extract due to defocusing blurringcaused by the fact that the aspheric normal aberration is greater than the depth of field of the system is solved.

Description

technical field

[0001] The invention belongs to the technical field of machine vision detection, and in particular relates to a method for automatically extracting a center of a defocused blurred centering image applied to a rotationally symmetrical aspheric optical element. Background technique

[0002] Aspherical optical components are widely used in large-aperture space telescopes, inertial confinement fusion (ICF), high-energy lasers and other systems. Due to uncontrollable forces in the manufacturing process, there will inevitably be defects on the surface of the components. These defects will not only affect The imaging quality of the optical system will also produce unnecessary scattering and diffraction in the high-energy laser system, which will cause energy loss and may cause secondary damage. Therefore, it is necessary to detect and evaluate surface defects. The aspheric element is centered so that its optical axis is as collinear as possible with the optical axis...

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