Weld quality inspection is a critical step in industrial manufacturing, where accurate and efficient defect detection directly impacts product reliability and operational safety.
Although many state-of-the-art (SOTA) deep learning methods have been designed and tested for weld defect classification, most remain computationally demanding, limiting their suitability for real-time or embedded inspection systems, and/or their predictive performance, when evaluated under strict protocols, is often insufficient to ensure robust operation in diverse industrial environments.
This paper presents the Efficient feature Modulation and Aggregation Network (EMAN), a novel lightweight convolutional architecture integrating efficient attention mechanisms and structural optimizations, alongside EMAN-S, an ultra-compact variant with extreme parameter efficiency. Both models were initially evaluated on four datasets of varying complexity: RIAWELC, NEU-CLS, StitchingNet, and Ball Screw Drive Defect. On the original RIAWELC dataset, the proposed architecture was compared against nine state-of-the-art (SOTA) models. EMAN achieved 99.71% accuracy and EMAN-S attained 99.80%, surpassing the baseline models across most metrics. However, our analysis revealed severe data leakage within the original RIAWELC distribution, indicating that these exceptionally high baseline results were heavily biased.
To mitigate this issue, we evaluated a selection of the best-performing models on a rigorously filtered version of the RIAWELC dataset devoid of data leakage. Under these strict conditions, EMAN and EMAN-S demonstrated robust generalization, achieving accuracies of 82.56% and 79.99%, recall rates of 78.27% and 74.50%, specificities of 94.53% and 93.68%, precisions of 78.48% and 74.33%, and F1 scores of 77.97% and 74.29%, respectively. Furthermore, after re-implementing the best-performing literature models, we rigorously benchmarked them against our proposed architectures on this filtered dataset as well as the three other aforementioned datasets.
Across the remaining benchmarks, EMAN achieved 99.61%, 98.87%, and 99.73% accuracy on the NEU-CLS, StitchingNet, and Ball Screw Drive Defect datasets, respectively, surpassing all compared architectures. The slim variant, EMAN-S, followed closely with accuracies of 97.89%, 93.41%, and 99.18%, respectively, still outperforming or matching the top competitors despite utilizing a mere 145 k parameters. Overall, the results indicate the superior performance and strong generalization capabilities of both proposed architectures across all utilized datasets.
Regarding inference latency, both proposed models operate at exceptional speeds: following TensorRT optimization on an NVIDIA RTX 4090 graphics card, EMAN-S achieves over 800 FPS, while EMAN reaches 500–550 FPS. Even under CPU-only execution (using an Intel Core i7-14700K), EMAN-S sustains a throughput of over 360 FPS, confirming its suitability for deployment in embedded edge devices and on-site industrial inspection systems.
These results confirm the proposed architectures as effective, scalable solutions for real-time industrial defect classification, combining state-of-the-art accuracy with exceptional computational efficiency.