Author Affiliations
College of Electrical Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, Chinashow less
Fig. 1. Flow chart of YOLOv2 algorithm
Fig. 2. YOLOv2 network structure
Fig. 3. Inception modules. (a) Module A; (b) module B
Fig. 4. NYOLOv2 structural diagram
Fig. 5. Three super classification examples of traffic signs. (a) Mandatory; (b) prohibitory; (c) danger
Fig. 6. Comparison of loss function curves
Fig. 7. Examples of detecting the loss function using YOLOv2
Fig. 8. Examples of detecting the loss function using NYOLOv2
Fig. 9. PR curves of three super categories. (a) Mandatory; (b) prohibitory; (c) danger
Threshold t | 0.10 | 0.20 | 0.40 | 0.50 | 0.60 | 0.65 |
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Precision | 0.7554 | 0.8699 | 0.9543 | 0.9648 | 09874 | 1.000 | Recall | 0.9568 | 0.9396 | 0.9102 | 0.8650 | 0.7959 | 0.6203 |
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Table 1. Precisions and recall rate values at different time thresholds
Method | mAP | FPS |
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YOLOv2 | 76.8 | 40.0 | NYOLOv2 | 83.2 | 55.0 |
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Table 2. Comparison of different architecture performances
Method | Prohibitory | Mandatory | Danger | Time /s |
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Precision /% | Recall /% | | Precision /% | Recall /% | Precision /% | Recall /% |
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YOLO | 98.55 | 92.15 | 96.68 | 70.56 | 90.89 | 78.11 | 0.221 | YOLOv2 | 99.06 | 87.64 | 98.24 | 69.06 | 97.65 | 75.03 | 0.154 | NYOLOv2 | 99.13 | 91.23 | 99.12 | 72.66 | 98.00 | 80.21 | 0.015 |
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Table 3. Comparison of classification results of three methods
Method | Precision /% | Recall /% | Time /s |
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Ref. [1] | 89.17 | 92.15 | 0.280 | Ref. [19] | 91.00 | 94.00 | 0.190 | NYOLOv2 (t=0.4) | 95.43 | 91.02 | 0.015 | NYOLOv2 (t=0.5) | 96.48 | 92.50 | 0.015 |
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Table 4. Comparison of processing time and performance of different methods
Method | Prohibitory /% | Mandatory /% | Danger /% | Time /s |
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Ref. [11] | 95.46 | 93.45 | 91.12 | 0.300 | Ref. [13] | 95.41 | 92.00 | 91.85 | 0.400-1.000 | Ref. [14] | 100.00 | 100.00 | 99.91 | 3.533 | NYOLOv2 | 96.21 | 97.96 | 92.44 | 0.015 |
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Table 5. AUC values and processing time for different methods