This study proposes a computer vision-based damage inspection system for road markings. In order to evaluate the degree of damage of a marking objectively, the proposed system estimates its damage ratio according to the marking's damaged part and the marking's region. A hierarchical semantic segmentation strategy is proposed which employs a series of convolutional neural networks to recognize the 2D bounding box, damaged part and region of a marking. Specifically, this strategy can effectively identify the original region of a marking through an improved U-Net even if the marking is significantly damaged. The damage ratio estimation is enhanced by integrating information from multiple images based on object tracking and dynamic homography estimation. The experimental results confirm that the proposed system is effective in automating the inspection of road markings and producing objective damage assessments that should significantly assist road managers in prioritizing maintenance operations.
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