Author Affiliations
1 Infrastructure Inspection Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China2 School of Science, Beijing Jiaotong University, Beijing 100044, Chinashow less
Fig. 1. Mirror reflection and image development
Fig. 2. Effect of mirror reflection on stripe extraction. (a) Mirror reflection at headband; (b) binarization result of Fig. 2(a); (c) mirror reflection on polished rail; (d) binarization result of Fig. 2(c)
Fig. 3. Gray-level distribution characteristics of laser stripe. (a) Laser stripe image; (b) gray-level distribution of laser stripe; (c) local zoom of Fig. 3(a); (d) local zoom of Fig. 3(b)
Fig. 4. Extraction process of light stripe center line based on sub-region multi-template matching
Fig. 5. Image segmentation performance statistics for different depth network structures [14]
Fig. 6. Rail profile data labeling
Fig. 7. Section partition of rail profile laser stripe
Fig. 8. Gradient direction of pixels.(a) Gradient direction solved for whole image; (b) gradient direction solved only on segmented light stripe
Fig. 9. Direction template corresponding to each sub-range of segmentation
Fig. 10. Extraction of pixel-level light stripe center based on direction template
Fig. 11. Extraction of sub-pixel level light stripe center based on gray-level centroid method
Fig. 12. Image rotation and scaling
Fig. 13. Comparison of light stripe segmentation results. (a) Original rail profile image; (b) fixed threshold binarization; (c) dynamic threshold binarization; (d) deep learning segmentation results
Fig. 14. Convolution features of light stripe image. (a) Convolution feature of first layer with size of 16×256×256; (b) convolution feature of second layer with size of 64×128×128; (c) convolution feature of third layer with size of 128×164×164
Fig. 15. Experimental results and corresponding local zoom for different laser stripe center extraction methods. (a) Gray-level centroid method[17]; (b) direction-template method [18]; (c) Steger method [19]; (d) proposed method
Fig. 16. Precision comparison of different laser stripe center extraction methods
Fig. 17. Execution time comparison of different laser strip center extraction methods
Image size /(pixel×pixel) | 800×600 | 960×200 | 480×100 |
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Time /ms | 12.3 | 6.4 | 1.8 | Frame rate /(frame·s-1) | 81 | 156 | 554 |
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Table 1. Segmentation time comparison of images with different sizes by ENet