J Shanghai Jiaotong Univ Sci ›› 2025, Vol. 30 ›› Issue (2): 291-299.doi: 10.1007/s12204-023-2608-9

• Engieering and Technology • Previous Articles     Next Articles

Weld Defect Monitoring Based on Two-Stage Convolutional Neural Network

基于两阶段卷积神经网络的焊缝缺陷监测

肖文波1,熊家凯2,余乐盛2,何银水3,马国红2   

  1. 1. Key Laboratory of Nondestructive Testing Ministry of Education, Nanchang Hangkong University, Nanchang 330063, China; 2. Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province, School of Advanced Manufacturing, Nanchang University, Nanchang 330031, China; 3. School of Resources and Environment, Nanchang University, Nanchang 330031, China
  2. 1.南昌航空大学 无损检测教育部重点实验室,南昌330063;2.南昌大学 先进制造学院 江西省轻质高强结构材料重点实验室,南昌330031;3.南昌大学 资源与环境学院,南昌330031
  • Accepted:2022-04-28 Online:2025-03-21 Published:2025-03-21

Abstract: Zn vapour is easily generated on the surface by fusion welding galvanized steel sheet, resulting in the formation of defects. Rapidly developing computer vision sensing technology collects weld images in the welding process, then obtains laser fringe information through digital image processing, identifies welding defects, and finally realizes online control of weld defects. The performance of a convolutional neural network is related to its structure and the quality of the input image. The acquired original images are labeled with LabelMe, and repeated attempts are made to determine the appropriate filtering and edge detection image preprocessing methods. Two-stage convolutional neural networks with different structures are built on the Tensorflow deep learning framework, different thresholds of intersection over union are set, and deep learning methods are used to evaluate the collected original images and the preprocessed images separately. Compared with the test results, the comprehensive performance of the improved feature pyramid networks algorithm based on the basic network VGG16 is lower than that of the basic network Resnet101. Edge detection of the image will significantly improve the accuracy of the model. Adding blur will reduce the accuracy of the model slightly; however, the overall performance of the improved algorithm is still relatively good, which proves the stability of the algorithm. The self-developed software inspection system can be used for image preprocessing and defect recognition, which can be used to record the number and location of typical defects in continuous welds.

Key words: defects monitoring, image preprocessing, Resnet101, feature pyramid network

摘要: 镀锌钢板熔接时容易在表面产生锌蒸气,从而形成缺陷。快速发展的计算机视觉传感技术在焊接过程中采集焊接图像,然后通过数字图像处理获得激光边缘信息,识别焊接缺陷,最终实现焊接缺陷的在线控制。卷积神经网络的性能与它的结构和输入图像的质量有关。用LabelMe对获取的原始图像进行标记,并反复尝试确定适当的过滤和边缘检测图像预处理方法。在Tensorflow深度学习框架上构建了不同结构的两级卷积神经网络,设置了不同的交集大于联合的阈值,并使用深度学习方法分别对采集的原始图像和预处理后的图像进行评估。与测试结果相比,基于基本网络VGG16的改进的特征金字塔网络算法的综合性能低于基本网络Resnet101图像的边缘检测将显著提高模型的准确性。增加模糊度会略微降低模型的准确性;但是,该改进算法的整体性能比较好,证明了该算法的稳定性。自主研发的软件检测系统可用于图像预处理和缺陷识别,可用于记录连续焊缝中典型缺陷的数量和位置。

关键词: 缺陷监测,图像预处理,Resnet101,特征金字塔网络

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