Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

Yi Feng Che; Guo Shun Yang; Li Guo Chen

doi:10.3969/j.issn.1000-1158.2023.04.05

Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

Translated title of the contribution: Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

Yi Feng Che
, Guo Shun Yang
, Li Guo Chen

Nuclear Fuels & Materials

Research output: Contribution to journal › Article › peer-review

Abstract

The higher the auto-focusing accuracy is, the smaller the perpendicular length measurement error of video measuring machine would be. The improved Tenengrad gradient evaluation function is selected by comparing the performance indexes of definition evaluation function. The full window is selected as the focus window. A search strategy combining rough and fine focus is proposed. In rough focus, mountain climbing search algorithm combined with binary search algorithm is used. And Gaussian curve fitting method combined with global search algorithm is used in fine focus. The experimental results show that the auto-focusing algorithm has good robustness and high accuracy which can reach 5μm (1/20 depth of field), and the average focusing time is 10 seconds which can meet the real-time requirements.

Translated title of the contribution	Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine
Original language	Chinese (Simplified)
Pages (from-to)	521-526
Number of pages	6
Journal	Jiliang Xuebao/Acta Metrologica Sinica
Volume	44
Issue number	4
Early online date	Apr 2023
DOIs	https://doi.org/10.3969/j.issn.1000-1158.2023.04.05
State	Published - Apr 2023

Keywords

auto-focusing technology
definition evaluation function
focus window
metrology
perpendicular length measurement
search strategy
video measuring machine

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10.3969/j.issn.1000-1158.2023.04.05

Cite this

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title = "Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine",

abstract = "The higher the auto-focusing accuracy is, the smaller the perpendicular length measurement error of video measuring machine would be. The improved Tenengrad gradient evaluation function is selected by comparing the performance indexes of definition evaluation function. The full window is selected as the focus window. A search strategy combining rough and fine focus is proposed. In rough focus, mountain climbing search algorithm combined with binary search algorithm is used. And Gaussian curve fitting method combined with global search algorithm is used in fine focus. The experimental results show that the auto-focusing algorithm has good robustness and high accuracy which can reach 5μm (1/20 depth of field), and the average focusing time is 10 seconds which can meet the real-time requirements.",

keywords = "auto-focusing technology, definition evaluation function, focus window, metrology, perpendicular length measurement, search strategy, video measuring machine",

author = "Che, \{Yi Feng\} and Yang, \{Guo Shun\} and Chen, \{Li Guo\}",

year = "2023",

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doi = "10.3969/j.issn.1000-1158.2023.04.05",

language = "Chinese (Simplified)",

volume = "44",

pages = "521--526",

journal = "Jiliang Xuebao/Acta Metrologica Sinica",

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T1 - Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

AU - Che, Yi Feng

AU - Yang, Guo Shun

AU - Chen, Li Guo

PY - 2023/4

Y1 - 2023/4

N2 - The higher the auto-focusing accuracy is, the smaller the perpendicular length measurement error of video measuring machine would be. The improved Tenengrad gradient evaluation function is selected by comparing the performance indexes of definition evaluation function. The full window is selected as the focus window. A search strategy combining rough and fine focus is proposed. In rough focus, mountain climbing search algorithm combined with binary search algorithm is used. And Gaussian curve fitting method combined with global search algorithm is used in fine focus. The experimental results show that the auto-focusing algorithm has good robustness and high accuracy which can reach 5μm (1/20 depth of field), and the average focusing time is 10 seconds which can meet the real-time requirements.

AB - The higher the auto-focusing accuracy is, the smaller the perpendicular length measurement error of video measuring machine would be. The improved Tenengrad gradient evaluation function is selected by comparing the performance indexes of definition evaluation function. The full window is selected as the focus window. A search strategy combining rough and fine focus is proposed. In rough focus, mountain climbing search algorithm combined with binary search algorithm is used. And Gaussian curve fitting method combined with global search algorithm is used in fine focus. The experimental results show that the auto-focusing algorithm has good robustness and high accuracy which can reach 5μm (1/20 depth of field), and the average focusing time is 10 seconds which can meet the real-time requirements.

KW - auto-focusing technology

KW - definition evaluation function

KW - focus window

KW - metrology

KW - perpendicular length measurement

KW - search strategy

KW - video measuring machine

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Auto-focusing Technology in Perpendicular Length Measurement of Video Measuring Machine

Abstract

Keywords

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