Study of Microscope Autofocus Based on Weighted Light Intensity

Huizong Lu; Mingliang Tu; Junjie Wu; Binghai Lv; Chengwu Wang

doi:doi:10.11648/j.ajpa.20210906.13

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Study of Microscope Autofocus Based on Weighted Light Intensity

Huizong Lu, Mingliang Tu, Junjie Wu, Binghai Lv, Chengwu Wang

Published in American Journal of Physics and Applications (Volume 9, Issue 6)

Received: 18 November 2021 Accepted: 2 December 2021 Published: 11 December 2021

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Abstract

Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.

Published in	American Journal of Physics and Applications (Volume 9, Issue 6)
DOI	10.11648/j.ajpa.20210906.13
Page(s)	146-156
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Laser Focus Deviation, Microscope Autofocus, Isotropic Surface, Anisotropic Surface, Weighted Light Intensity Q

References

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APA Style

Huizong Lu, Mingliang Tu, Junjie Wu, Binghai Lv, Chengwu Wang. (2021). Study of Microscope Autofocus Based on Weighted Light Intensity. American Journal of Physics and Applications, 9(6), 146-156. https://doi.org/10.11648/j.ajpa.20210906.13

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ACS Style

Huizong Lu; Mingliang Tu; Junjie Wu; Binghai Lv; Chengwu Wang. Study of Microscope Autofocus Based on Weighted Light Intensity. Am. J. Phys. Appl. 2021, 9(6), 146-156. doi: 10.11648/j.ajpa.20210906.13

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AMA Style

Huizong Lu, Mingliang Tu, Junjie Wu, Binghai Lv, Chengwu Wang. Study of Microscope Autofocus Based on Weighted Light Intensity. Am J Phys Appl. 2021;9(6):146-156. doi: 10.11648/j.ajpa.20210906.13

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@article{10.11648/j.ajpa.20210906.13,
  author = {Huizong Lu and Mingliang Tu and Junjie Wu and Binghai Lv and Chengwu Wang},
  title = {Study of Microscope Autofocus Based on Weighted Light Intensity},
  journal = {American Journal of Physics and Applications},
  volume = {9},
  number = {6},
  pages = {146-156},
  doi = {10.11648/j.ajpa.20210906.13},
  url = {https://doi.org/10.11648/j.ajpa.20210906.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajpa.20210906.13},
  abstract = {Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.},
 year = {2021}
}

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TY  - JOUR
T1  - Study of Microscope Autofocus Based on Weighted Light Intensity
AU  - Huizong Lu
AU  - Mingliang Tu
AU  - Junjie Wu
AU  - Binghai Lv
AU  - Chengwu Wang
Y1  - 2021/12/11
PY  - 2021
N1  - https://doi.org/10.11648/j.ajpa.20210906.13
DO  - 10.11648/j.ajpa.20210906.13
T2  - American Journal of Physics and Applications
JF  - American Journal of Physics and Applications
JO  - American Journal of Physics and Applications
SP  - 146
EP  - 156
PB  - Science Publishing Group
SN  - 2330-4308
UR  - https://doi.org/10.11648/j.ajpa.20210906.13
AB  - Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.
VL  - 9
IS  - 6
ER  -

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Author Information

Huizong Lu

College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China
Mingliang Tu

Department of Electrical & Mechanical Engineering, Shaoxing Vocational & Technical Colleg, Shaoxing, China
Junjie Wu

College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China
Binghai Lv

College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou, China
Chengwu Wang

College of Mechanical Engineering, Zhejiang Normal University, Jinhua, China

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APA Style

Huizong Lu, Mingliang Tu, Junjie Wu, Binghai Lv, Chengwu Wang. (2021). Study of Microscope Autofocus Based on Weighted Light Intensity. American Journal of Physics and Applications, 9(6), 146-156. https://doi.org/10.11648/j.ajpa.20210906.13

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ACS Style

Huizong Lu; Mingliang Tu; Junjie Wu; Binghai Lv; Chengwu Wang. Study of Microscope Autofocus Based on Weighted Light Intensity. Am. J. Phys. Appl. 2021, 9(6), 146-156. doi: 10.11648/j.ajpa.20210906.13

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AMA Style

Huizong Lu, Mingliang Tu, Junjie Wu, Binghai Lv, Chengwu Wang. Study of Microscope Autofocus Based on Weighted Light Intensity. Am J Phys Appl. 2021;9(6):146-156. doi: 10.11648/j.ajpa.20210906.13

Copy | Download

@article{10.11648/j.ajpa.20210906.13,
  author = {Huizong Lu and Mingliang Tu and Junjie Wu and Binghai Lv and Chengwu Wang},
  title = {Study of Microscope Autofocus Based on Weighted Light Intensity},
  journal = {American Journal of Physics and Applications},
  volume = {9},
  number = {6},
  pages = {146-156},
  doi = {10.11648/j.ajpa.20210906.13},
  url = {https://doi.org/10.11648/j.ajpa.20210906.13},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajpa.20210906.13},
  abstract = {Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.},
 year = {2021}
}

Copy | Download

TY  - JOUR
T1  - Study of Microscope Autofocus Based on Weighted Light Intensity
AU  - Huizong Lu
AU  - Mingliang Tu
AU  - Junjie Wu
AU  - Binghai Lv
AU  - Chengwu Wang
Y1  - 2021/12/11
PY  - 2021
N1  - https://doi.org/10.11648/j.ajpa.20210906.13
DO  - 10.11648/j.ajpa.20210906.13
T2  - American Journal of Physics and Applications
JF  - American Journal of Physics and Applications
JO  - American Journal of Physics and Applications
SP  - 146
EP  - 156
PB  - Science Publishing Group
SN  - 2330-4308
UR  - https://doi.org/10.11648/j.ajpa.20210906.13
AB  - Microscopes auto focusing is critically important for a great spectrum of scientific and industrial applications. Finding the best focus position for variety of surfaces under measurement proved to be challenging. In order to provide a rapid and accurate method for microscope focusing positioning, a laser focus deviate system was employed for microscope focusing position. The relationship between focusing sensitivity and the surface under measurement was investigated. First, the laser focus deviate technique is introduced in light of characteristic parameters such as the diameter of the focused spot, the laser wavelength and the distance from the optimal focus. Then, the focusing displacement versus spot position curve fitting is performed for a smooth isotropic surface to directly locate the best focusing position. Following, it is analyzed that when applied to anisotropic and rough surfaces, the centroid of the image spot after reflection/scattering from the surface will deviate from its original light intensity distribution, thus deviate from the calculated optimal focus position and cause focusing errors. Finally, a criterion of weighted light intensity value Q is introduced to achieve fast focusing of anisotropic surfaces in combination with the laser focusing deviate technique. The experimental results show that for a 20× microscope objective system, the focusing accuracy of this focusing positioning method is 1.7 μm on smooth surfaces; and is at the micro meter level for rough surfaces. It basically meets the requirements for rapid, stable and reliable microscope auto focusing needs.
VL  - 9
IS  - 6
ER  -

Copy | Download