Research On Dual Channel Image Acquisition System For Subsurface Defects Of Large Aperture Optical Elements

With the rapid development of human society,advanced fields such as clean energy,military equipment,and space exploration increasingly rely on high-precision optical systems,and the quality and stability requirements of large-aperture,high-precision optical elements are becoming more stringent.Sub-surface defects are an important factor in reducing the laser damage threshold of optical elements,which can cause damage to elements under high-density laser irradiation.The current detection principles and methods for sub-surface defects are still in the development stage,especially for large-diameter components.High-precision and high-efficiency methods for detecting elements sub-surface defects are an important subject in the field of optical inspection today.This paper studies the sub-surface defect detection methods of large-aperture optical elements,respectively explores the large-aperture optical element detection and sub-surface defect detection technologies,and conducts experiments and data analysis based on the built-up testing prototypeIn terms of sub-surface defect detection technology,this paper selects fused silica elements,and studies the dark-field scattering and fluorescence microscopy dual-channel image fusion method based on its sub-surface defect light scattering characteristics and photoluminescence effect.Aiming at the inconsistency of the dual-channel image field of view,this paper studies and proposes a correction method for the dual-channel image acquisition system,and also analyzes the results of the correction experiment.In terms of large-aperture optical element detection hardware technology,a high-precision multi-dimensional platform hardware system is designed and manufactured to support large-aperture element scanning.In terms of algorithm,this paper studies the sub-aperture scanning stitching method that can improve the system resolution,analyzes the shortcomings of the traditional serpentine scanning method,improves the sub-area scanning method,and proves the superiority of the sub-area scanning method through experiments.In addition,the systematic error in the sub-aperture scanning method is studied,and solutions to the angle error of the field of view coordinate and the field of view size calibration error are givenFinally,the experiment verifies the system’s high-precision scanning capability,detection capability and data processing capability for subsurface defects of large-caliber fused silica components.