Surface defect detection is a critical task in industrial production process. Nowadays, there are lots of detection methods based on computer vision and have been successfully applied in industry, they also achieved good results. However, achieving full automation of surface defect detection remains a challenge, due to the complexity of surface defect, in intra-class, while the defects between inter-class contain similar parts, there are large differences in appearance of the defects. To address these issues, this paper proposes a pyramid feature fusion and global context attention network for pixel-wise detection of surface defect, called PGA-Net. In the framework, the multi-scale features are extracted at first from backbone network. Then the pyramid feature fusion module is used to fuse these features into five resolutions through some efficient dense skip connections. Finally, the global context attention module is applied to the fusion feature maps of adjacent resolution, which allows effective information propagate from low-resolution fusion feature maps to high-resolution fusion ones. In addition, the boundary refinement block is added to the framework to refine the boundary of defect and improve the result of predict. The final prediction is the fusion of the five resolutions fusion feature maps. The results of evaluation on four real-world defect datasets demonstrate that the proposed method outperforms the state-of-the-art methods on mean Intersection of Union and mean Pixel Accuracy (NEU-Seg: 82.15%, DAGM 2007: 74.78%, MT_defect: 71.31%, Road_defect: 79.54%).

Pavement distress detection is of great significance for road maintenance and to ensure road safety. At present, detection methods based on deep learning have achieved outstanding performance in related fields. However, these methods require large-scale training samples. For pavement distress detection, it is difficult to collect more images with pavement distress, and the types of pavement diseases are increasing with time, so it is impossible to ensure sufficient pavement distress samples to train the supervised deep model. In this article, we propose a new few-shot pavement distress detection method based on metric learning, which can effectively learn new categories from a few labeled samples. In this article, we adopt the backend network (ResNet18) to extract multilevel feature information from the base classes and then send the extracted features into the metric module. In the metric module, we introduce the attention mechanism to learn the feature attributes of “what” and “where” and focus the model on the desired characteristics. We also introduce a new metric loss function to maximize the distance between different categories while minimizing the distance between the same categories. In the testing stage, we calculate the cosine similarity between the support set and query set to complete novel category detection. The experimental results show that the proposed method significantly outperforms several benchmarking methods on the pavement distress dataset (the classification accuracies of 5-way 1-shot and 5-way 5-shot are 77.20% and 87.28%, respectively).

Pavement distress detection is of significance for road maintenance and traffic safety. Manual pavement distress detection suffers from high workloads, inefficiency, low accuracy, and high cost. To replace the manual operations in the pre-filling detection with the aim to improve efficiency and reduce cost, this paper proposes a three-stage automatic inspection and evaluation system for pavement distress based on improved deep convolutional neural networks (CNNs). First, the system integrates multi-level context information from the CNN classification model to construct discriminative super-features to determine whether there is distress in the pavement image and the type of the distress, so as to achieve rapid detection of pavement distress. Then, the pavement images with distress are fed into the CNN segmentation model to highlight the distress region with pixel-wise. In the segmentation model, a novel pyramid feature extraction module and a novel guidance attention mechanism are introduced. Finally, we evaluate the degree of pavement damage according to the segmentation results of the CNN segmentation model. In the experiments, we compare our classification model and segmentation model with other state-of-the-art methods on two pavement distress datasets, and the results demonstrate that the proposed models achieve out-performance on different evaluation metrics.