Welcome to Journal of Graphics share: 

Journal of Graphics ›› 2025, Vol. 46 ›› Issue (3): 568-577.DOI: 10.11996/JG.j.2095-302X.2025030568

• Image Processing and Computer Vision • Previous Articles     Next Articles

Detection of apparent defects in a small sample of industrial products with category imbalance

WANG Suqin1(), DU Yujie1, SHI Min1(), ZHU Dengming2,3   

  1. 1. College of Control and Computer Engineering, North China Electric Power University, Beijing 102206, China
    2. Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100190, China
    3. Taicang Institute of Information Technology, Taicang Jiangsu 215400, China
  • Received:2024-06-20 Accepted:2024-12-22 Online:2025-06-30 Published:2025-06-13
  • Contact: SHI Min
  • About author:First author contact:

    WANG Suqin (1970-), associate professor, master. Her main research interests cover computer vision, intelligent software technology. E-mail:wsq@ncepu.edu.cn

  • Supported by:
    Frontier Technology Research Project of Suzhou Science and Technology Programme(SYG202327)

Abstract:

It has been demonstrated that generic target detection networks exhibit reduced overall detection accuracy when the number of defect samples is limited and the distribution of defect categories is uneven. Furthermore, the detection accuracy is markedly diminished for tail categories with particularly scarce defect samples. Based on these observations, an improved method for detecting apparent defects in industrial products using YOLOv8s was developed. Phantom convolution GSConv was employed in the Neck network to diminish the network complexity while simultaneously augmenting its nonlinearity, thus circumventing the potential issue of overfitting. Furthermore, the aggregation module VoV-GSCSP was employed to facilitate the extraction and fusion of features at varying levels, thereby enhancing the network’s capacity for feature extraction and fusion. A reweighted loss function was adopted to balance the training loss contributions across different categories of samples, increasing the loss contribution percentage for the tail category and thereby enhancing defect detection accuracy for the tail category. In comparison with the baseline model, the enhanced method achieved a mAP of 93.3% for the apparent defect detection accuracy in acupuncture needles, representing a 5.0% enhancement, and achieved a 9.1% improvement for broken needle defects. It should be noted that these improvements were achieved with the minimal number of samples. For medicinal plates, a mAP of apparent defect detection accuracy was achieved at 91.4%, representing a 2.6% improvement, and the improvement for dirty defects with the fewest samples was achieved at 3.2%. On the steel dataset, which featured a greater number of samples with uneven distribution, the overall defect detection accuracy improved by 2.6% in mAP. The experiments demonstrated that the enhanced methodology can markedly enhance the overall detection accuracy of apparent defects in industrial products under conditions of the limited number of defect samples and the imbalanced distribution of categories. Furthermore, it can markedly enhance the detection accuracy for categories with sparse samples, exhibiting excellent generalization capabilities.

Key words: apparent defect detection, small sample size, class imbalance, GSConv, re-weighting loss function

CLC Number: