Chinese Journal of Lasers, Volume. 47, Issue 1, 0104003(2020)

Laser Triangulation Method for Glass Thickness by Automatically Adapting to Displacement Change

Kaimei Liu, Wei Tao, Xiao Chen, Zhi Li, and Hui Zhao*
Author Affiliations
  • Department of Instrument Science and Engineering, School of Electronic Information and Electric Engineering,Shanghai Jiao Tong University, Shanghai 200240, China
  • show less

    When we measure glass thickness using the traditional triangulation method, the relative position of the glass and probe should be kept fixed. When the position of the glass changes, it must be recalibrated to accurately measure thickness. To address this problem, a multi-position glass-thickness-measurement method based on laser triangulation that can automatically adapt to displacement changes is proposed in this paper. By this method, glass thickness can be measured directly when glass position changes. Firstly, the relationship between the glass thickness and spacing of imaging spots of the reflected light from the front and back surfaces of the glass is analyzed when the glass is at the standard position. Then, the relationship among the spacing of imaging spots, position of front surface of the glass, and glass thickness is analyzed when the glass displacement changes. The corresponding mathematical model is established, and a compensation algorithm is proposed herein to correct the influence of the glass displacement change on the glass-thickness measurement. Finally, a laser triangulation system based on a laser-diode-complementary metal-oxide semiconductor (LD-CMOS) is designed, and multiple glass samples with known thicknesses are used for calibration and measurement experiments. Experimental results show that when the glass position changes within the range of 1-4.5 mm, the absolute errors of glass-thickness measurement at different positions are less than 0.010 mm and the relative errors are within 0.5%. The proposed method can thus realize high-precision glass-thickness-measurement without repeated calibration when the glass is at different positions, displaying good practicability, flexibility, and versatility.

    Tools

    Get Citation

    Copy Citation Text

    Kaimei Liu, Wei Tao, Xiao Chen, Zhi Li, Hui Zhao. Laser Triangulation Method for Glass Thickness by Automatically Adapting to Displacement Change[J]. Chinese Journal of Lasers, 2020, 47(1): 0104003

    Download Citation

    EndNote(RIS)BibTexPlain Text
    Save article for my favorites
    Paper Information

    Category: measurement and metrology

    Received: Jun. 25, 2019

    Accepted: Sep. 26, 2019

    Published Online: Jan. 9, 2020

    The Author Email: Hui Zhao (huizhao@sjtu.edu.cn)

    DOI:10.3788/CJL202047.0104003

    Topics