Abstract
In this paper, we propose a convolutional neural network (CNN) based method that inspects non-patterned welding defects (craters, pores, foreign substances and fissures) on the surface of the engine transmission using a single RGB camera. The proposed method consists of two steps: first, extracting the welding area to be inspected from the captured image, and then determining whether the extracted area includes defects. In the first step, to extract the welding area from the captured image, a CNN based approach is proposed to detect a center of the engine transmission in the image. In the second stage, the extracted area is identified by another CNN as defective or non-defective. To train the second stage CNN stably, we propose a class-specific batch sampling method. With our sampling method, biased learning caused by data imbalance (number of collected defective images is much less than that of non-defective images) is effectively prevented. We evaluated our system with a large amount of samples (about 32,000 images) collected manually from the production line, and our system shows a remarkable performance in all experiments.
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Abbreviations
- i :
-
Input nodes of layer
- o :
-
Output nodes of layer
- w :
-
Learnable weights of layer
- b :
-
Bias of layer
- \({\mathcal{F}}\) :
-
Activation function
- c :
-
Estimated center of the engine transmission
- \(\hat{c}\) :
-
Ground truth center of the engine transmission
- N :
-
Number of training samples in a batch
- r 1 :
-
Lower radius of the welding area
- r 2 :
-
Upper radius of the welding area
- θ 1 :
-
Lower angle of the welding area
- θ 2 :
-
Upper angle of the welding area
- p :
-
Probability distribution of the estimated class
- \(\hat{p}\) :
-
Probability distribution of the ground truth class
References
Chu, H. H., & Wang, Z. Y. (2017). A study on welding quality inspection system for shell-Tube heat exchanger based on machine vision. International Journal of Precision Engineering and Manufacturing, 18(6), 825–834.
Jia, H., Murphey, Y. L., Shi, J., & Chang, T. S. (2004). An intelligent real-time vision system for surface defect detection. In Proceedings of the 17th international conference on pattern recognition (Vol. 3, pp. 239–242).
Shen, H., Li, S., Gu, D., & Chang, H. (2012). Bearing defect inspection based on machine vision. Measurement, 45(4), 719–733.
Chu, H. H., & Wang, Z. Y. (2016). A vision-Based system for post-Welding quality measurement and defect detection. The International Journal of Advanced Manufacturing Technology, 86(9–12), 3007–3014.
Funck, J. W., Zhong, Y., Butler, D. A., Brunner, C. C., & Forrer, J. B. (2003). Image segmentation algorithms applied to wood defect detection. Computers and Electronics in Agriculture, 41(1–3), 157–179.
Yang, W., Li, D., Zhu, L., Kang, Y., & Li, F. (2009). A new approach for image processing in foreign fiber detection. Computers and Electronics in Agriculture, 68(1), 68–77.
Min, H. G., Kang, D. J., Kim, K. J., & Park, J. H. (2017). New non-contact measurement method of deformation at tensile test of thin film via digital image correlation technique. International Journal of Precision Engineering and Manufacturing, 18(11), 1509–1517.
Kwon, B. K., Won, J. S., & Kang, D. J. (2015). Fast defect detection for various types of surfaces using random forest with VOV features. International Journal of Precision Engineering and Manufacturing, 16(5), 965–970.
Ngan, H. Y., Pang, G. K., Yung, S. P., & Ng, M. K. (2005). Wavelet based methods on patterned fabric defect detection. Pattern Recognition, 38(4), 559–576.
Kumar, A., & Pang, G. K. (2002). Defect detection in textured materials using Gabor filters. IEEE Transactions on Industry Applications, 38(2), 425–440.
Tsai, D. M., & Lai, S. C. (2008). Defect detection in periodically patterned surfaces using independent component analysis. Pattern Recognition, 41(9), 2812–2832.
Zhou, W., Fei, M., Zhou, H., & Li, K. (2014). A sparse representation based fast detection method for surface defect detection of bottle caps. Neurocomputing, 123, 406–414.
Shumin, D., Zhoufeng, L., & Chunlei, L. (2011). AdaBoost learning for fabric defect detection based on HOG and SVM. In 2011 International conference on multimedia technology (pp. 2903–2906).
Krizhevsky, A., Sutskever, I., & Hinton, G. E. (2012). ImageNet classification with deep convolutional neural networks. In Advances in neural information processing systems (pp. 1097–1105).
Park, J. K., Kwon, B. K., Park, J. H., & Kang, D. J. (2016). Machine learning-based imaging system for surface defect inspection. International Journal of Precision Engineering and Manufacturing-Green Technology, 3(3), 303–310.
Masci, J., Meier, U., Ciresan, D., Schmidhuber, J., & Fricout, G. (2012). Steel defect classification with max-pooling convolutional neural networks. In 2012 International joint conference on neural networks (IJCNN) (pp. 1–6).
Faghih-Roohi, S., Hajizadeh, S., Núñez, A., Babuska, R., & De Schutter, B. (2016). Deep convolutional neural networks for detection of rail surface defects. In 2016 International joint conference on neural networks (IJCNN) (pp. 2584–2589).
Soukup, D., & Huber-Mörk, R. (2014). Convolutional neural networks for steel surface defect detection from photometric stereo images. In Advances in visual computing lecture notes in computer science (pp. 668–677).
Wu, X., Cao, K., & Gu, X. (2017). A surface defect detection based on convolutional neural network. In Lecture notes in computer science computer vision systems (pp. 185–194).
Khumaidi, A., Yuniarno, E. M., & Purnomo, M. H. (2017). Welding defect classification based on convolution neural network (CNN) and Gaussian kernel. In 2017 International Seminar on Intelligent Technology and Its Applications (ISITIA), Surabaya (pp. 261–265).
Park, J. K., & Kang, D. J. (2018). Unified convolutional neural network for direct facial keypoints detection. The Visual Computer. https://doi.org/10.1007/s00371-018-1561-3.
Nair, V., & Hinton, G. E. (2010). Rectified linear units improve restricted boltzmann machines. In Proceedings of the 27th international conference on machine learning (ICML-10) (pp. 807–814).
Kimme, C., Ballard, D., & Sklansky, J. (1975). Finding circles by an array of accumulators. Communications of the ACM, 18(2), 120–122.
Acknowledgements
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT) (No. 2016R1A2B4007608) and National IT Industry Promotion Agency (NIPA) Grant funded by the Korea government (MSIT) (No. S0602-17-1001) and partly supported by Cooperative R&D fund of Korea Ministry of SMEs and Startups (S2605414).
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Park, JK., An, WH. & Kang, DJ. Convolutional Neural Network Based Surface Inspection System for Non-patterned Welding Defects. Int. J. Precis. Eng. Manuf. 20, 363–374 (2019). https://doi.org/10.1007/s12541-019-00074-4
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DOI: https://doi.org/10.1007/s12541-019-00074-4