Fig. 1. Flowchart of concrete pavement crack detection

Fig. 2. Concrete pavement crack image dataset. (a) No-crack images; (b) crack images

Fig. 3. Crack images that may be disregarded in detection

Fig. 4. Cutting process diagram for crack images using overlapping sliding window technology

Fig. 5. ILGCHDN classification model structure diagram

Fig. 6. Convolution block of the ILGCHDN model

Fig. 7. Comparison of the renderings by two algorithms after binarization of 6 crack images. (a) Original crack images; (b) label marking images; (c) renderings of the global threshold method; (d) renderings of the adaptive threshold method

Fig. 8. Schematic diagram of calculating crack width in image coordinate system

Fig. 9. Accuracy diagram of the training model

Fig. 10. Loss diagram of the training model

Fig. 11. Error comparison histogram for crack width measurement