Open AccessMicroscope autofocus algorithm based on number of image slope variations
Author(s) -
Jing-Feng Weng,
Guo-Hao Lu,
ChunJen Weng,
Yu-Hsin Lin,
Chaofeng Liu,
Robbie Vincke,
H. C. Ting,
Tingting Chang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.421926
Subject(s) - autofocus , optics , focus (optics) , computer science , lens (geology) , algorithm , microscope , interferometry , cardinal point , interference (communication) , computer vision , artificial intelligence , physics , telecommunications , channel (broadcasting)
This paper presents a passive autofocus algorithm applicable to interferometric microscopes. The proposed algorithm uses the number of slope variations in an image mask to locate the focal plane (based on focus-inflection points) and identify the two neighboring planes at which fringes respectively appear and disappear. In experiments involving a Mirau objective lens, the proposed algorithm matched the autofocusing performance of conventional algorithms, and significantly outperformed detection schemes based on zero-order interference fringe in dealing with all kinds of surface blemish, regardless of severity. In experiments, the proposed algorithm also proved highly effective in cases without fringes.