• Laser & Optoelectronics Progress
  • Vol. 55, Issue 2, 020001 (2018)
Xi Zhang* and Jian Zhang
Author Affiliations
  • School of Mechatronics Engineering and Automation, Shanghai University, Shanghai 200072, China
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    DOI: 10.3788/LOP55.020001 Cite this Article Set citation alerts
    Xi Zhang, Jian Zhang. Summary on Calibration Method of Line-Structured Light[J]. Laser & Optoelectronics Progress, 2018, 55(2): 020001 Copy Citation Text show less
    Main calibration method of light plane
    Fig. 1. Main calibration method of light plane
    Schematic of zigzag piece calibration
    Fig. 2. Schematic of zigzag piece calibration
    Diagram of calibration method based on parallel straight line constraint. (a) Planar target; (b) projected image
    Fig. 3. Diagram of calibration method based on parallel straight line constraint. (a) Planar target; (b) projected image
    Diagram of P3P. (a) Schematic of light plane calibration; (b) plane geometric model of point
    Fig. 4. Diagram of P3P. (a) Schematic of light plane calibration; (b) plane geometric model of point
    No.Calibration targetThumbnailTypeManufacturing methodCalibration characteristic
    12000,zigzag block[23]3DComputer numericalcontrol cuttingHigh-precision auxiliary servo deviceis required. Measuring coordinate systemis set along the light plane. Using directlinear transform (DLT) method tocomplete the calibraion. Calibrationaccuracy is 0.048 mm[23].
    21999,target with twoperpendicularplanes[24-25]Customized three-dimensional target, highmanufacturing costs. Occlusion existing inimaging process. Use principle of crossratio of invariance for calibration.Calibration accuracy is 0.145 mm[24].
    32014,gauge block[12]GrindingGauge block are standard parts with highprecision. But calibration process requireshigh precision auxiliary servo device.Calirbation accuracy is 0.0279 mm[12].
    42015,ball target[29]Ball target are standard parts with highprecision. Space cone fitting and spacesphere fitting is used for calibration.Calibration accuracy is 0.04 mm[29].
    52016,chessboard[32]Easy for feature extraction. Camera and lightplane could be calibrated simultaneouslywith only one target. But it's difficult tomanufacture a large scale target.Calibration accuracy is 0.09 mm[32].
    62006,array targetwith circles[33]2DEasy for feature extraction. Camera and lightplane could be calibrated simultaneously withonly one target. But it's difficult tomanufacture a large scale target. Calibrationaccuracy is 0.107 mm[33].
    72014,parallel straightlines[30]Photpetching /printingUseparrallel straight lines constraints forcalibration.The calibration method isnovel. Calibration accuracy is 0.134 mm[30].
    92012,single circularring target[34]Camera and light plane could be calibratedsimultaneously. Operation is flexibleand easy for site calibration.Calibration accuracy is 0.0368 mm[34].
    102010,one-dimensionaltarget[27]1DEasy for manufacturing large size target, andfit for site calibration in larget FOV. Useprinciple of vanishing point for calibration.Calibration accuracy is 0.102 mm[27].
    112016,linear scale[35]Calibration accuracy is high, but it needshigh-precision auxiliary device. The target isparticularly fit for applications of small FOVand high accuracy. Calibration accuracyis 0.013 mm[35].
    Table 1. List of commonly used calibration targets
    No.Evaluation indicatorEvaluation objectEvaluation method
    1Plane fittingaccuracyLightplaneAverage or maximum of the distance fromcontrol points to fitting plane is computed asthe accuracy results[40].
    2RepeatabilitySingle lineardimensionA fixed dimension would be measured formany times, and the maximum, minimum and variancewill be used as the accuracy indicator for repeatability [41].
    3Light-planecompositeaccuracyDimensions fromany directionin light planeBased on cross ratio, distance between two control pointsin local world frame would be obtained as the true value,then the corresponding control points would be measuredin 3D coordinate. Finally, the RMS will be computedas the evaluation results[30].
    4Light-planeseparatingaccuracyDimensions alongwith coordinate axesin light planeThe measurement results with gauge block would betaken as the accuracy in vertical direction, and themeasurement results with linear scale could be treatedas the accuracy in horizontal direction[35].
    5SurfacereconstructionaccuracyPoint cloudafter curveaccumulationThe reconstructed curves would be accumulated alongthe motion direction, and the comparison ofpoint cloud and CAD model will be taken as thesurface reconstruction accuracy[42].
    Table 2. Evaluation of calibration accuracy of commonly used line structured light
    Xi Zhang, Jian Zhang. Summary on Calibration Method of Line-Structured Light[J]. Laser & Optoelectronics Progress, 2018, 55(2): 020001
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