Fast and adaptive auto-focusing algorithm for microscopic cell observation

Takeshi Obara, Yasunobu Igarashi, Koichi Hashimoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)

Abstract

In biological and medical sciences, optical microscopes are widely used. By using the microscope, we can observe cellular dynamics including intracellular ions and molecules tagged with fluorescent dyes at a high magnification. However, a freely motile cell easily escapes from a field of view and a focal plane of the typical microscope. Therefore, we propose a novel auto-focusing (AF) algorithm and develop an AF and tracking microscope. XYZ positions of a microscopic stage are visual feedback controlled to focus and track the cell automatically. A bright-field image is used to estimate a cellular position. XY centroids are used to estimate XY positions of the tracked cell. To estimate a Z position, we use a diffraction pattern around the cell membrane. This estimation method is so-called Depth from Diffraction (DFDi). However, this method is not robust for individual differences between cells because the diffraction pattern depends on each cellular shape, reflective index and transparency. Therefore, in this study, we propose a real-time correction of DFDi by using 2D Laplacian of a center region of the cell as a goodness of the focus. To evaluate the performance of our developed algorithm and microscope, we auto-focus and track a freely moving paramecium. In this experimental result, the paramecium is auto-focused and kept inside the scope of the microscope during 45s. The evaluated focal error is within 5[μm], while a length and a thickness of the paramecium are about 200[μm] and 50[μm], respectively.

Original languageEnglish
Title of host publicationIROS'11 - 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems
Subtitle of host publicationCelebrating 50 Years of Robotics
Pages7-12
Number of pages6
DOIs
Publication statusPublished - 2011 Dec 29
Event2011 IEEE/RSJ International Conference on Intelligent Robots and Systems: Celebrating 50 Years of Robotics, IROS'11 - San Francisco, CA, United States
Duration: 2011 Sep 252011 Sep 30

Publication series

NameIEEE International Conference on Intelligent Robots and Systems

Other

Other2011 IEEE/RSJ International Conference on Intelligent Robots and Systems: Celebrating 50 Years of Robotics, IROS'11
CountryUnited States
CitySan Francisco, CA
Period11/9/2511/9/30

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Software
  • Computer Vision and Pattern Recognition
  • Computer Science Applications

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