基于波前传感的快速自动聚焦技术及其应用  

Wavefront sensing based autofocus method and its applications

作　　者：徐静 高淑梅[1] 蒋志龙 孔艳[1] 刘诚[1] 王绶玙[1] XU Jing;GAO Shu-mei;JIANG Zhi-long;KONG Yan;LIU Cheng;WANG Shou-yu(Computational Optics Laboratory,School of Science,Jiangnan University,Wuxi Jiangsu 214122,China)

机构地区：[1]江南大学理学院,计算光学实验室,江苏无锡214122

出　　处：《光电子．激光》2020年第1期46-55,共10页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61705092,U1730132);江苏省自然科学基金(BK20170194,BK20180598);江南大学科研重点项目(JUSRP51721B)资助项目。

摘　　要：光学显微技术以其特有的优势广泛应用于生物医学领域。在显微成像中,样品聚焦是实现高质量成像的重要前提,对于传统的基于图像分析的自动聚焦技术,大量的多焦面数据采集限制了其广泛应用。本文提出了一种基于波前传感的快速自动聚焦技术,仅需采集三幅离焦强度图,通过求解强度传递方程提取离焦相位并获得离焦波前,随后将此波前沿光轴方向数值传播,最后对得到的一系列强度信息进行在焦评价,定位在焦位置。此外,为了进一步加快自动聚焦速度,本文还在硬件方面结合GPU并行运算,在算法方面通过减少像素数量明显提高了波前传感自动聚焦技术的效率。快速波前传感自动聚焦技术只需记录少量的多焦面数据,操作简单,且聚焦速度快,精度高,可应用于显微成像系统进行高质量的在焦观察和测量。Optical microscopy is widely used in biological and medical fields with its unique advantages.In microscopic imaging,sample focusing is an important prerequisite for high-quality imaging.For traditional image-based autofocus technology,a large number of multi-focal image acquisition limits its wide applications.In this paper,a high-speed autofocusing technology based on wavefront sensing is proposed.First,three defocus intensities equidistant along the optical axis are captured.Then,the phase distribution at defocus position is retrieved by solving the transport-of-intensity equation.Next,various wavefront distributions along optical axis can be numerically computed using wavefront propagation with the defocus wavefront.Finally,focal plane can be located according to in-focus criterion from those numerically computed wavefront at various planes.However,the required phase retrieval,numerical wavefront propagation,and in-focus determination are often time consuming,inevitably limiting its high-speed applications.Therefore,GPU based parallel computing and pixel reduction are also implemented to further improve autofocusing speed.Proved by experiments with different specimens,the time consumption was reduced to 2.76 sec and 1.94 sec compared with 21.35 sec and 15.32 sec at the beginning,respectively.Considering its fast speed,high accuracy and compact equipment,it is believed the provided autofocusing technique can be applied in microscopes for high-quality in-focus observations and measurements.

关 键 词：自动聚焦 波前传感 GPU并行运算 像素数目减少 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]