微型靶件装配中自动对焦方法的研究

Research on auto-focus method for microtarget assembly

惯性约束激光聚变(ICF)实验对微靶的装配精度要求越来越高,基于机器视觉的在线监测系统是微靶零件测量的主要手段。精确的光学聚焦是进行稳定、高精度测量的前提。提出了一种基于三维精密位移平台的主动对焦方法。通过实验选取了合适的清晰度评价函数。采用大步长找区域,小步长找点的搜索策略,实现了系统的快速精确对焦,调焦精度可优于10μm,总体调焦时间约为30 s。克服了手动调焦时间长,不能保证成像完全清晰的问题。

Inertial confinement fusion （ICF） needs micro-target in high precision assembly, and the online monitoring system based on machine vision is the primary means of target measuring. Precise optical focusing is the premise of stable, high-precision measurements. An active auto-focus method based on 3D precise shift platform is proposed. The system achieves fast and precise focus. Sttitab/e definition evaluation function is selected through experiment. Searching strategy uses long step to find the region, small step to find the precision focus point. It is proved that the precision is better than 10ptm,and the overall time is about 30s. The issue that using long time and not entirely clear of manual focus is overcomed.