• Laser & Optoelectronics Progress
  • Vol. 56, Issue 7, 071202 (2019)
Yanqiong Shi1、**, Qiuxia Ying2, and Rongsheng Lu2、*
Author Affiliations
  • 1 School of Mechanical and Electrical Engineering, Anhui Jianzhu University, Hefei, Anhui 230601, China
  • 2 School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei, Anhui 230009, China
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    DOI: 10.3788/LOP56.071202 Cite this Article Set citation alerts
    Yanqiong Shi, Qiuxia Ying, Rongsheng Lu. Performance Analysis of Three-Dimensional Measurement Algorithm with Focus Variation Microscopic Imaging[J]. Laser & Optoelectronics Progress, 2019, 56(7): 071202 Copy Citation Text show less
    Schematic of focus variation
    Fig. 1. Schematic of focus variation
    Ideal focusing curve
    Fig. 2. Ideal focusing curve
    An experimental image obtained using focus variation microscopy and three testing points
    Fig. 3. An experimental image obtained using focus variation microscopy and three testing points
    Focus curves obtained from single point information and neighborhood information with different operators. (a) Brenner operator; (b) Roberts operator; (c) Laplace operator; (d) Tenengrad operator; (e) SMD operator; (f) gradient square; (g) Sobel operator in eight directions
    Fig. 4. Focus curves obtained from single point information and neighborhood information with different operators. (a) Brenner operator; (b) Roberts operator; (c) Laplace operator; (d) Tenengrad operator; (e) SMD operator; (f) gradient square; (g) Sobel operator in eight directions
    Focus scatter plots with different sizes of neighborhood. (a) 5; (b) 9; (c)13; (d) 17
    Fig. 5. Focus scatter plots with different sizes of neighborhood. (a) 5; (b) 9; (c)13; (d) 17
    Focusing evaluation results of points with different brightness. (a) (380,280); (b) (700,390); (c) (608,218)
    Fig. 6. Focusing evaluation results of points with different brightness. (a) (380,280); (b) (700,390); (c) (608,218)
    Focusing evaluation results of three brighter points. (a) (765,115); (b) (363,1095); (c) (829,68)
    Fig. 7. Focusing evaluation results of three brighter points. (a) (765,115); (b) (363,1095); (c) (829,68)
    Schematic of wavelet fusion method
    Fig. 8. Schematic of wavelet fusion method
    Comparison of image fusion results. (a) Image fusion based on spatial regional characteristics; (b) image fusion with frequency domain wavelet; (c) color image fusion with frequency domain wavelet
    Fig. 9. Comparison of image fusion results. (a) Image fusion based on spatial regional characteristics; (b) image fusion with frequency domain wavelet; (c) color image fusion with frequency domain wavelet
    Experimental system
    Fig. 10. Experimental system
    Image sequence diagrams of coin surface. (a) 1st image; (b) 2nd image; (c) 30th image; (d) 31st image; (e) 80th image; (f) 81st image
    Fig. 11. Image sequence diagrams of coin surface. (a) 1st image; (b) 2nd image; (c) 30th image; (d) 31st image; (e) 80th image; (f) 81st image
    3D measurement results of coin surface relief. (a) 3D point cloud; (b) 3D color reconstruction image
    Fig. 12. 3D measurement results of coin surface relief. (a) 3D point cloud; (b) 3D color reconstruction image
    A gauge step measurement result. (a) One of images in image sequence; (b) 3D point cloud data; (c) point cloud distribution of a section
    Fig. 13. A gauge step measurement result. (a) One of images in image sequence; (b) 3D point cloud data; (c) point cloud distribution of a section
    OperatorTime /s
    Single pointNeighborhood
    Brenner0.132.58
    Roberts1.583.24
    Laplace1.813.40
    Tenengrad0.312.70
    SMD0.162.58
    Gradient square0.162.59
    Sobel operator in eight directions10.814.12
    Table 1. Time consumed per image during focus evaluation by using single point and neighborhood information
    Neighborhood size /pixelTime /s
    52.31
    92.37
    132.44
    172.57
    Table 2. Time consumed per image during focus evaluation with different sizes of neighborhood
    PointcoordinatesTraversalsearchTwo polynomialfittingGaussianfittingMaximum valuequadratic fittingMaximum valueGaussian fittingMaximum valueRANSAC
    (380,280)4846.2947.8648.2348.4048.10
    (700,390)4949.5048.4748.9348.8948.93
    (608,218)5047.5250.8349.5949.5249.33
    (363,1095)4683.6744.4845.7745.5945.79
    (829,68)749.7823.8574.2374.4274.26
    Table 3. Comparison of results obtained by different extremum searching methods
    Yanqiong Shi, Qiuxia Ying, Rongsheng Lu. Performance Analysis of Three-Dimensional Measurement Algorithm with Focus Variation Microscopic Imaging[J]. Laser & Optoelectronics Progress, 2019, 56(7): 071202
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