Open AccessCompact multi-band fluorescent microscope with an electrically tunable lens for autofocusing
Author(s) -
Zhaojun Wang,
Ming Lei,
Baoli Yao,
Yanan Cai,
Yansheng Liang,
Yue Yang,
Yang Xiao-yan,
Hui Li,
Daxi Xiong
Publication year - 2015
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.6.004353
Subject(s) - microscope , optics , lens (geology) , focus (optics) , autofocus , computer science , equidistant , signal (programming language) , materials science , physics , mathematics , geometry , programming language
Autofocusing is a routine technique in redressing focus drift that occurs in time-lapse microscopic image acquisition. To date, most automatic microscopes are designed on the distance detection scheme to fulfill the autofocusing operation, which may suffer from the low contrast of the reflected signal due to the refractive index mismatch at the water/glass interface. To achieve high autofocusing speed with minimal motion artifacts, we developed a compact multi-band fluorescent microscope with an electrically tunable lens (ETL) device for autofocusing. A modified searching algorithm based on equidistant scanning and curve fitting is proposed, which no longer requires a single-peak focus curve and then efficiently restrains the impact of external disturbance. This technique enables us to achieve an autofocusing time of down to 170 ms and the reproductivity of over 97%. The imaging head of the microscope has dimensions of 12 cm × 12 cm × 6 cm. This portable instrument can easily fit inside standard incubators for real-time imaging of living specimens.