• Laser & Optoelectronics Progress
  • Vol. 56, Issue 4, 041102 (2019)
Qingwei Wu1, Haidong Fan2, Jian Guan2, Yingchun Wu1, and Xuecheng Wu1,*
Author Affiliations
  • 1 State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
  • 2 Zhejiang Energy Group Co., LTD., Hangzhou, Zhejiang 310007, China
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    DOI: 10.3788/LOP56.041102 Cite this Article Set citation alerts
    Qingwei Wu, Haidong Fan, Jian Guan, Yingchun Wu, Xuecheng Wu. Surface Profile Measurement of Coal Based on Structured Light Multifrequency Phase-Shifting Technique[J]. Laser & Optoelectronics Progress, 2019, 56(4): 041102 Copy Citation Text show less
    Schematic of experimental device
    Fig. 1. Schematic of experimental device
    Coal with smooth surface. (a) Fringe pattern; (b) background intensity; (c) binary image of coal and shadow; (d) binary image of valid measurement area
    Fig. 2. Coal with smooth surface. (a) Fringe pattern; (b) background intensity; (c) binary image of coal and shadow; (d) binary image of valid measurement area
    Binary images of phase point distribution for two phase types of coal with smooth surface. (a) First type; (b) second type
    Fig. 3. Binary images of phase point distribution for two phase types of coal with smooth surface. (a) First type; (b) second type
    Phase distributions of coal with smooth surface. (a) First type of phase points before correction; (b) first type of phase points after correction; (c) second type of phase points before correction; (d) second type of phase points after correction
    Fig. 4. Phase distributions of coal with smooth surface. (a) First type of phase points before correction; (b) first type of phase points after correction; (c) second type of phase points before correction; (d) second type of phase points after correction
    Phase distribution of coal with smooth surface after correction
    Fig. 5. Phase distribution of coal with smooth surface after correction
    Coal with non-smooth surface. (a) Fringe pattern; (b) background intensity; (c) binary image of valid measurement area
    Fig. 6. Coal with non-smooth surface. (a) Fringe pattern; (b) background intensity; (c) binary image of valid measurement area
    Binary images of phase point distributions of two phase types of coal with non-smooth surface. (a) First type; (b) second type
    Fig. 7. Binary images of phase point distributions of two phase types of coal with non-smooth surface. (a) First type; (b) second type
    Phase distributions of coal with non-smooth surface after correction. (a) First type of phase points; (b) second type of phase points
    Fig. 8. Phase distributions of coal with non-smooth surface after correction. (a) First type of phase points; (b) second type of phase points
    Phase distributions of coal with non-smooth surface after correction by different methods. (a) Proposed method; (b) method in Ref. [15]; (c) method in Ref. [16]; (d) method in Ref. [17]
    Fig. 9. Phase distributions of coal with non-smooth surface after correction by different methods. (a) Proposed method; (b) method in Ref. [15]; (c) method in Ref. [16]; (d) method in Ref. [17]
    Cinder. (a) Background intensity; (b) phase distribution in valid measurement area after correction
    Fig. 10. Cinder. (a) Background intensity; (b) phase distribution in valid measurement area after correction
    Point cloud of coal. (a) Smooth surface; (b) non-smooth surface
    Fig. 11. Point cloud of coal. (a) Smooth surface; (b) non-smooth surface
    Standard gauge block. (a) Fringe pattern; (b) 3D point cloud
    Fig. 12. Standard gauge block. (a) Fringe pattern; (b) 3D point cloud
    SampleNumber of validphase pointsProportion of firsttype points /%Proportion of secondtype points /%Proportion of pointsin queue /%
    Smooth coal47784797.202.803.26
    Non-smooth coal34685189.7110.2916.99
    Cinder18231598.921.081.38
    Table 1. Distributions of phase points
    SampleProposedMethod in Ref. [15]Method in Ref. [16]Method in Ref. [17]
    Smooth coal0.181.940.112.02
    Non-smooth coal1.922.150.08~5751.53
    Cinder0.10---
    Table 2. Running time for different algorithmss
    Qingwei Wu, Haidong Fan, Jian Guan, Yingchun Wu, Xuecheng Wu. Surface Profile Measurement of Coal Based on Structured Light Multifrequency Phase-Shifting Technique[J]. Laser & Optoelectronics Progress, 2019, 56(4): 041102
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