• Laser & Optoelectronics Progress
  • Vol. 61, Issue 4, 0437005 (2024)
Yan Wang, Jichuan Xing*, and Yaozhi Wang
Author Affiliations
  • School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China
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    DOI: 10.3788/LOP223222 Cite this Article Set citation alerts
    Yan Wang, Jichuan Xing, Yaozhi Wang. Coal and Gangue Recognition Method Based on Dual-Channel Pseudocolor Image by Lidar[J]. Laser & Optoelectronics Progress, 2024, 61(4): 0437005 Copy Citation Text show less
    Example maps of production environment and industrial camera data. (a) Data collection environment; (b) data acquisition by industrial camera
    Fig. 1. Example maps of production environment and industrial camera data. (a) Data collection environment; (b) data acquisition by industrial camera
    Schematic diagram of acquisition system
    Fig. 2. Schematic diagram of acquisition system
    Point cloud images. (a) Distance point cloud; (b) intensity point cloud
    Fig. 3. Point cloud images. (a) Distance point cloud; (b) intensity point cloud
    Image of coal and gangue strength. (a) Coal; (b) gangue
    Fig. 4. Image of coal and gangue strength. (a) Coal; (b) gangue
    Example of distance point cloud
    Fig. 5. Example of distance point cloud
    Process of image preprocessing
    Fig. 6. Process of image preprocessing
    Background denoising. (a) Before removal; (b) after removal
    Fig. 7. Background denoising. (a) Before removal; (b) after removal
    Point cloud image generation process. (a) Original point cloud map; (b) vertical view of point cloud; (c) real point cloud projection; (d) two dimension intensity pixel image
    Fig. 8. Point cloud image generation process. (a) Original point cloud map; (b) vertical view of point cloud; (c) real point cloud projection; (d) two dimension intensity pixel image
    Dual channel pseudo color image generation process. (a) Intensity point cloud; (b) distance point cloud; (c) dual channel pseudo color image
    Fig. 9. Dual channel pseudo color image generation process. (a) Intensity point cloud; (b) distance point cloud; (c) dual channel pseudo color image
    DenseNet-121 network structure
    Fig. 10. DenseNet-121 network structure
    Dual channel pseudo color image used in the experiment. (a) Coal; (b) gangue
    Fig. 11. Dual channel pseudo color image used in the experiment. (a) Coal; (b) gangue
    Training accuracy and training loss curves. (a) (d) DenseNet-40; (b) (e) DenseNet-121; (c) (f) DenseNet-201
    Fig. 12. Training accuracy and training loss curves. (a) (d) DenseNet-40; (b) (e) DenseNet-121; (c) (f) DenseNet-201
    ParameterValue
    Scanning frequency /Hz600
    Laser wavelength /nm660
    Scanning range /(°)70
    Angular resolution /(°)0.0833
    Working distance /m0.7‒3
    Measurement accuracy /mm±1
    Table 1. Parameters of LMS4000
    LayerOutput sizeDenseNet-40DenseNet-121
    Convolution112×1127×7Conv,s=27×7Conv,s=2
    Pooling56×563×3max pool,s=23×3max pool,s=2
    Dense block(1)56×561×1Conv3×3Conv×61×1Conv3×3Conv×6
    Transition layer(1)56×561×1Conv1×1Conv
    28×282×2average pool,s=22×2average pool,s=2
    Dense block(2)28×281×1Conv3×3Conv×61×1Conv3×3Conv×12
    Transition layer(2)28×281×1Conv1×1Conv
    14×142×2average pool,s=22×2average pool,s=2
    Dense block(3)14×141×1Conv3×3Conv×61×1Conv3×3Conv×24
    Transition layer(3)14×141×1Conv
    7×72×2average pool,s=2
    Dense block(4)7×71×1Conv3×3Conv×16
    Classification layer1×17×7global average pool7×7global average pool
    1000D fully-connecter,softmax1000D fully-connecter,softmax
    Table 2. Parameters of DenseNet-40 and DenseN-121
    ModelSize /106FLOPs /109
    AlexNet61.00.7
    GoogleNet7.01.6
    VGG-19144.015.5
    ResNet5025.03.9
    DenseNet400.21.3
    DenseNet1218.05.7
    Table 3. FLOPs and parameter quantity of common models
    ModelAccuracy /%PRF1
    DenseNet-4094.560.960.970.97
    DenseNet-12193.490.910.970.94
    DenseNet-20192.740.900.960.93
    ResNet-10183.530.820.860.84
    VGG-1992.540.900.950.93
    Xception90.240.890.920.90
    Table 4. Cross validation average results
    Yan Wang, Jichuan Xing, Yaozhi Wang. Coal and Gangue Recognition Method Based on Dual-Channel Pseudocolor Image by Lidar[J]. Laser & Optoelectronics Progress, 2024, 61(4): 0437005
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