Optics and Precision Engineering, Volume. 29, Issue 9, 2065(2021)

Non-contact wave height measurement method based on laser incident spot recognition

Jun WU1...2,*, Yue-jie SHU3, Shi-bao CAO1,2, and Yu-hang QIU12 |Show fewer author(s)
Author Affiliations
  • 1Chongqing Southwest Research Institute for Water Transport Engineering, Chongqing Jiaotong University, Chongqing40006, China
  • 2Key Laboratory of Inland Waterway Regulation Engineering Ministry of Transport, Chongqing Jiaotong University, Chongqing400074, China
  • 3Chongqing Xike Waterway Engineering Consulting Center, Chongqing400016, China
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    Figures & Tables(15)
    Wave height recording curve
    Measuring principle of wave height based on laser spot
    Imaging geometry
    Binary image of laser entry characteristics
    Binary image template
    Search process
    Calculation result of similarity measure
    Experimental devices for non-contact wave height measurement
    Calibration devices for wave height measurement
    Calibration curve
    Wave simulator
    Comparison of wave simulation and measurement results
    • Table 1. [in Chinese]

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      Table 1. [in Chinese]

      目的:搜索图像S中的激光光斑的坐标

      输入:每帧图像f、模板A

      While(f)

      #f为帧编号

      提取每帧单色图像,得到灰度图像

      采用阈值分割算法,对灰度图像进行二值化,得到二值化图像

      For θ=0°:1°:20°

      计算旋转矩阵:M=cos θ-sin θsin θcos θ

      For i=SX:1:SX+n

      For j=SY:1:SY+m

      #(SXSY):左上角像素坐标

      #mn: 模板像素尺寸

      计算相似度函数:Eθ,i,j

      End

      End

      End

      计算最小测度函数值minEθ,i,j

      θ0=θ|minminEθ,i,j

      旋转角度为θ0时的相似度测度函数构成二维强度图,该图谷底坐标即为匹配的搜索子图位置:i0,j0=i,j|minEθ0,i,j

      激光光斑图像坐标:u,v=i0+n2,j0+m2

      更新搜索区域,新的ROI区域中心坐标为i0,j0,长宽分别为2n和2m

      End

      输出:每帧图像激光光斑的图像坐标系列(ul,vl)l=0,1,….
    • Table 1. Parameters of non-contact wave height measurement experimental devices

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      Table 1. Parameters of non-contact wave height measurement experimental devices

      参数类型参数指标
      结构参数H50 cm
      H010 cm
      α45°
      摄像机参数像素1 920×1 080
      水平视场角ω89°
      帧率30 frame/s
      半导体激光器参数功率100 mW
      波长650 nm
      光斑模式点状
      光斑直径3 mm(1 m距离)
    • Table 2. Calibration result of wave height sensor

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      Table 2. Calibration result of wave height sensor

      光斑像素坐标

      水位测针

      测量值H/mm

      像素距离

      实际位置

      /mm

      标定公式计算值

      /mm

      误差

      /mm

      uv
      47973201 015.57360359.540.46
      55273010942.54350350.43-0.43
      61772820877.51340340.30-0.30
      67572630819.48330330.06-0.06
      72672440768.44320320.31-0.31
      77872250716.40310309.740.26
      82672060668.36300299.440.56
      87072070624.39290289.540.46
      91071880584.34280280.07-0.07
      95271690542.30270269.600.40
      988714100506.25260260.11-0.11
      1 024712110470.21250250.05-0.05
      1 058712120436.22240239.960.04
      1 088712130406.24230230.49-0.49
      1 119712140375.26220220.07-0.07
      1 146710150348.21210210.37-0.37
      1 172710160322.22200200.47-0.47
      1 197708170297.17190190.32-0.32
      1 221708180273.18180179.980.02
      1 243706190251.13170169.910.09
      1 264706200230.14160159.770.23
      1 284706210210.15150149.570.43
      1 302704220192.09140139.880.12
      1 320706230174.18130129.780.22
      1 336704240158.11120120.29-0.29
      1 353704250141.13110109.790.21
      1 368704260126.14100100.11-0.11
      1 383702270111.079089.960.04
      1 39870428096.198079.510.49
      1 41170229083.107069.960.04
      1 42470230070.116060.13-0.13
      1 43770231057.145049.950.05
      1 44970032045.044040.12-0.12
      1 46170233033.243030.21-0.21
      1 47370034021.102019.660.34
      1 48470035010.20109.890.11
      1 4946983600.000以该点为零点
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    Jun WU, Yue-jie SHU, Shi-bao CAO, Yu-hang QIU. Non-contact wave height measurement method based on laser incident spot recognition[J]. Optics and Precision Engineering, 2021, 29(9): 2065

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    Paper Information

    Category: Modern Applied Optics

    Received: Dec. 31, 2020

    Accepted: --

    Published Online: Nov. 22, 2021

    The Author Email: WU Jun (195575462@qq.com)

    DOI:10.37188/OPE.20212909.2065

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