ETDNet: Efficient Transformer-Based Detection Network for Surface Defect Detection.

Deep learning (DL)-based surface defect detectors play a crucial role in ensuring product quality during inspection processes. However, accurately and efficiently detecting defects remain challenging due to specific characteristics inherent in defective images, involving a high degree of foreground-background similarity, scale variation, and shape variation. To address this challenge, we propose an efficient transformer-based detection network, ETDNet, consisting of three novel designs to achieve superior performance. First, ETDNet takes a lightweight vision transformer (ViT) to extract representative global features. This approach ensures an accurate feature characterization of defects even with similar backgrounds. Second, a channel-modulated feature pyramid network (CM-FPN) is devised to fuse multilevel features and maintain critical information from corresponding levels. Finally, a novel task-oriented decoupled (TOD) head is introduced to tackle inconsistent representation between classification and regression tasks. The TOD head employs a local feature representation (LFR) module to learn object-aware local features and introduces a global feature representation (GFR) module, based on the attention mechanism, to learn content-aware global features. By integrating these two modules into the head, ETDNet can effectively classify and perceive defects with varying shapes and scales. Extensive experiments on various defect detection datasets demonstrate the effectiveness of the proposed ETDNet. For instance, it achieves AP 46.7% (versus 45.9%) and AP50 80.2% (versus 79.1%) with 49 frames/s on NEU-DET. The code is available at https://github.com/zht8506/ETDNet.