Magnetic Tile Research Articles

MTGGAN: generate type-controllable magnetic tile defect data to improve defect detection performance

ABSTRACT The scarcity of training samples and label information poses a major challenge for deep learning defect detection technology. Using generative models to expand sample data is considered an effective approach to address this issue. However, existing GAN models struggle to generate high-fidelity and type-controllable magnetic tile defect samples. Therefore, this paper proposes a type-controllable magnetic tile generation method (MTGGAN) that generates data with inherent label information. The model enhances fidelity and diversity in conditional generation through dual discriminator, auxiliary classifier, and auxiliary generator mechanisms. Additionally, focal loss is introduced to address the model’s class tendency issue during training. Extensive experiments demonstrate that, compared to advanced GAN methods, samples generated by MTGGAN exhibit superior quality and diversity. Furthermore, the generated data can train superior detection models. Effectively alleviating the problem of data scarcity in defect detection.

Segmentation-assisted classification model with convolutional neural network for weld defect detection

Detecting weld defects in battery trays is crucial for the safety of new energy vehicles. Existing methods for weld surface defect detection, relying on traditional computer vision algorithms and convolutional neural networks with substantial image-level labeled data, face challenges in accurately identifying small defects, especially with limited samples. To address these issues, we developed an innovative Segmentation-Assisted Classification with Convolutional Neural Networks (SACNN) model. SACNN integrates a common feature extraction subnet, a segmentation subnet enhanced by a multi-scale feature fusion module, and a classification subnet specifically designed for precise defect detection. A joint loss function co-trains the segmentation and classification subnets using both image-level and pixel-level labels, enhancing the model’s ability to accurately detect small defect regions. Our model demonstrates notable improvement, achieving accuracy gains ranging from 2% to 18% compared to existing state-of-the-art methods, with an overall accuracy of 94.09% on an industrial dataset of battery tray welds. To further evaluate the generalization capability of our model, we evaluated it on the publicly available Magnetic Tile dataset, achieving state-of-the-art results in this challenging context. Additionally, we conducted comprehensive ablation studies to validate the contribution of each component in our approach and utilized visualization techniques to enhance the interpretability of our model. These advancements represent a significant contribution to the state of the art in aluminum alloy weld defect detection.

A lightweight parallel attention residual network for tile defect recognition

In modern industrial production, permanent magnet motors are an indispensable part of industrial manufacturing. The quality of the magnetic tiles directly affects the working performance of the permanent magnet motors, making the detection of defects on the surface of magnetic tiles critically important. However, due to the small size of defects on the tile image and the reflectivity of the defective surface, the details of image characteristics are not prominently acquired.These problems bring a lot of difficulties for the recognition of magnetic tile defects. In this paper, a magnetic tile defect detection method is proposed for the probAlems of unclear image features and small defects. First, the image is processed using linear variation to enhance the image detail features. Then, by introducing the inverted bottleneck block structure in MobileNetV2, the Attention Parallel Residual Convolution Block (APR) is proposed, and the Lightweight Parallel Attention Residual Network (LPAR-Net) is built. In APR Block, 7 × 7 convolution is introduced so that the model can extract spatial features from a larger range, and weighted fusion of input images by residual structure. In addition, in this paper, CBAM is improved, split into two parts and inserted into APR Block. Finally, the mainstream image classification models and the LPAR-Net proposed in this paper are used for comparison, respectively. The experimental results show that the method achieves 93.63% accuracy on the adopted dataset, which is better than the existing mainstream image classification network models DenseNet, MobileNet, ConvNext and so on. In addition, this paper introduces a strip steel surface defect dataset and compares it with the above image classification model, which verifies that the detection method proposed in this paper still has strong recognition capability.

MT-U2Net: Lightweight detection network for high-precision magnetic tile surface defect localization

Automated surface defect localization is closely related to product quality control. Although many image segmentation models have achieved excellent results in industrial defect localization, the wide-ranging defects in magnetic tile materials and the similarity between textures and background textures make it difficult to balance detection model performance and model size. Therefore, we propose a new magnetic tile defect localization model called MT-U2Net. The model consists of three parts: Dres-Ublock, U2 structure, and attention mechanism. Dres-Ublock is used to enhance the model's feature extraction capability and reduce its size; the U2-Net structure is utilized to learn cross-scale defect information; the attention mechanism is employed to eliminate redundant information. MT-U2Net improves detection performance across various defect scales. In the test set, MT-U2Net achieves an F1 Score of 0.840 and an MAE of 0.024 and compresses the model size to 3.39 M. Extensive experimental results show that MT-U2Net outperforms existing state-of-the-art algorithms in magnetic tile defect detection performance and model size.

DEU-Net: A Multi-Scale Fusion Staged Network for Magnetic Tile Defect Detection

DEU-Net: A Multi-Scale Fusion Staged Network for Magnetic Tile Defect Detection

Attention-based convolution neural network for magnetic tile surface defect classification and detection

Effectively identifying surface defects in magnetic tiles has proven to be highly challenging due to limited sample availability and irrelevant background interference, which also plays a crucial role in significantly influencing the lifespan and reliability of permanent magnet motors. To address these challenges, our study draws inspiration from a comprehensive analysis of the retinal attention mechanism and proposes three guiding criteria: multi-level resolution, what to look for, and where to look at. These criteria are utilized as foundational principles to enhance the representation learning capability of designed neural network structures through the incorporation of the retinal attention mechanism. Subsequently, based on these guiding criteria, we introduce a novel convolutional retinal attention block (CRAB) to learn discriminative and robust feature representations for magnetic tile surface defect classification and detection. The proposed CRAB comprises three modules: multi-resolution module (MRM), global attention aggregation module (GAAM), and local attention aggregation module (LAAM), designed to extract discriminative and robust features by refining meaningful information and suppressing redundant ones. Comprehensive experimental results across image classification and object detection tasks demonstrate that the proposed CRAB outperforms existing methods such as SE, ECA, and CBAM, and can effectively amplify the representation power across various backbone networks, including VGG-16, GoogLeNet, ResNet-18, and ResNet-50. An evaluation on surface defect classification and detection tasks for industrial magnetic tiles further shows that CRAB achieves accuracies of 99.50% and 96.98%, respectively. These results emphasize the promising application prospects of the proposed method in detecting industrial surface defects amid expansive and inconsequential backgrounds. The code of the proposed method is available at: https://github.com/KWflyer/CRAB.

Robustness defect detection: Improving the performance of surface defect detection in interference environment

In industrial production environments, the performance of surface defect detection methods for products is affected by disturbances in the equipment, manufacturing processes, and the environment, resulting in poor robustness of the training model. In this paper, an improved defect detection method based on feature extraction fusion and dynamic label assignment is proposed. Three improved network structures, i.e., the adaptive feature recognition convolution (AFRC), path aggregation balanced feature pyramid, and dynamic label assignment, are proposed for the feature extraction, feature fusion, and detection phases of the existing Faster RCNN model, respectively. The AFRC is employed to improve the feature extraction ability of the model for irregular defects, the path balance feature pyramid is utilized to enhance the recognition ability of the model for different levels of feature maps, and the dynamic label assignment is employed to improve the quality of the candidate frames. Under disturbed environments, the results of the proposed improvements outperform the benchmark faster RCNN model in terms of average precision (AP) by 4.1%, 3.7%, and 4.2% on an aluminum surface defect dataset and by 1.8%, 2.2%, and 3.7% AP on a magnetic tile surface defect dataset. The experimental results demonstrate that the proposed scheme effectively improves the robustness of the baseline model in environments with various disturbances.

Optimising digital signal processor‐based defect detection in smart manufacturing with lightweight convolutional neural networks

AbstractIndustrial defect detection is an important part of intelligent manufacturing, and Internet of things (IoT)‐based defect detection is receiving more and more attention. Although deep learning (DL) can help defect detection reduce the cost and improve the accuracy of traditional manual quality inspection, DL requires huge computational resources and is difficult to be simply deployed on IoT devices with limited computational power and memory resources. Digital signal processor (DSP) is an important IoT device with small size, high performance and low energy consumption, which has been widely used in intelligent manufacturing. In order to perform accurate defect detection on DSP, the authors proposed various optimisation strategies and then used a parallel scheme to scale the model to execute on multiple cores. The authors’ method evaluated it on Northeastern University Surface Defect Dataset, Magnetic Tile Defect Dataset, Rail Surface Defect Dataset and Silk Cylinder Defect Dataset, and the experimental results showed that the authors’ method obtains faster speeds without accuracy loss compared to running the same Convolutional Neural Networks model on a mainstream desktop CPU. This means that the authors’ method can realise efficient and accurate defect detection on IoT devices with limited computational power and memory resources, which opens up new possibilities for future development in the field of smart manufacturing.

Surface defect segmentation of magnetic tiles based on cross self-attention module

The detection of magnetic tile quality is an essential link before the assembly of permanent magnet motor. In order to meet the high standard of magnetic tile surface defect detection and realize the rapid and automatic segmentation of magnetic tile defects, a magnetic tile surface defect segmentation algorithm based on cross self-attention model (CSAM) is proposed. It adopts high-low level semantic feature fusion method to build the dependency relationship between the deep and shallow features. Multiple auxiliary loss functions are used to constrain the network and reduce the noise in the deep features. In addition, an image enhancement method is also designed to solve the problem of insufficient annotated data. The experimental results show that the network can achieve 79.6% mIoU and 98.5% PA, which can meet the high standard requirements of magnetic tile manufacturing.

Magnetic tile fault detection of high‐voltage electric machines: A multiview feature selection method via consistent soft label

AbstractImage‐based scheme has attracted wide attention in the fault detection of high‐voltage permanent magnet motors, but it often suffers from the shooting conditions. Multiview feature selection allows multisource information to be fused, which can improve the accuracy and robustness of image detection. Therefore, we propose multiview unsupervised consistency via soft‐label feature selection (MUCSFS). This method constructs consistent pseudo labels through soft labels from clustering affinity of each view sample and builds the model by integrating selection constraints into the graph model. This model filters the fault data set to obtain the feature subset, which is used for clustering. We verify the method's effectiveness by simulating multiview data. The fault clustering experiment on the high‐voltage motors' magnetic tile fault data set confirm that our method can effectively cluster the fault categories.

Knowledge Distillation for Enhancing a Lightweight Magnet Tile Target Detection Model: Leveraging Spatial Attention and Multi-Scale Output Features

Accurate and efficient sorting of diverse magnetic tiles during manufacturing is vital. However, challenges arise due to visual similarities among types, necessitating complex computer vision algorithms with large sizes and high computational needs. This impedes cost-effective deployment in the industry, resulting in the continued use of inefficient manual sorting. To address this issue, we propose an innovative lightweight magnetic tile detection approach that improves knowledge distillation for a compressed YOLOv5s model. Incorporating spatial attention modules into different feature extraction stages of YOLOv5s during the knowledge distillation process can enhance the ability of the compressed model to learn the knowledge of intermediate feature extraction layers from the original large model at different stages. Combining different outputs to form a multi-scale output, the multi-scale output feature in the knowledge refinement process enhances the capacity of the compressed model to grasp comprehensive target knowledge in outputs. Experimental results on our self-built magnetic tile dataset demonstrate significant achievements: 0.988 mean average precision, 0.5% discrepancy compared to the teacher’s network, and an 85% model size reduction. Moreover, a 36.70% boost in inference speed is observed for single image analysis. Our method’s effectiveness is also validated by the Pascal VOC dataset results, showing potential for broader target detection scenarios. This approach offers a solution to magnetic tile target detection challenges while being expected to expand to other applications.

Radial Magnetic Levitation and Its Application to Density Measurement, Separation, and Detection of Microplastics.

This work describes the development of radial magnetic levitation (MagLev) using two radially magnetized ring magnets to solve the problem of limited operational spaces in standard MagLev and the major shortcoming of a short working distance in axial MagLev. Interestingly and importantly, we demonstrate that for the same magnet size, this new configuration of MagLev doubles the working distance over the axial MagLev without significantly sacrificing the density measurement range, whether for linear or nonlinear analysis. Meanwhile, we develop a magnetic assembly method to fabricate the magnets for the radial MagLev, where multiple magnetic tiles with single-direction magnetization are used as assembly elements. On this basis, we experimentally demonstrate that the radial MagLev has good applicability in density-based measurement, separation, and detection and show its advantages in improving separation performance compared with the axial MagLev. The open structure of two-ring magnets and good levitation characteristics make the radial MagLev have great application potential, and the performance improvement brought by adjusting the magnetization direction of magnets provides a new perspective for the magnet design in the field of MagLev.

A domain adaptation YOLOv5 model for industrial defect inspection

In the process of industrial production, manufactured products are prone to surface defects for a variety of reasons. To overcome the problem of high time cost and the strong demand for large sample data sets, a detector based on transfer learning is commonly utilized. In this paper, a domain adaptation YOLOv5 model, named DAYOLOv5, is proposed for automatic surface defect inspection. The hyperparameter α in DAYOLOv5 for knowledge transfer can be designed specially to achieve better generalization in real-world industrial applications. Meanwhile, in the field of magnetic tile surface defect detection, our DAYOLOv5 outperforms traditional mixed training and pretrain-finetune methods with limited data sets and has great robustness. Overall, the experimental results demonstrate that our DAYOLOv5 model can indeed boost performance on small-scale target data sets and is applicable to practical industrial scenarios.

Detection of Surface Defects of Magnetic Tiles Based on Improved YOLOv5

The typical defect detection algorithm is ineffective due to the contrast between the magnetic tile defect and the various defect features. An improved YOLOv5‐based algorithm, for detecting magnetic tile defects with varying defect features, is suggested. The procedure begins by incorporating the CBAM into feature extraction network of YOLOv5. It improves the feature of network learning capabilities for the target region by filtering and weighting the feature vectors in such a way that the processing of network is dominated by the essential target characteristics. A new loss function of detection model is then proposed according to the properties of the magnetic tile picture, and the confidence of prediction box is increased. Data augmentation technologies are introduced to increase the number of data samples. Based on magnetic tile defect datasets, the evaluation results have shown that the precision of the proposed approach is 98.56%, 3.21%, and 7.22% greater than the original YOLOv5 and Faster R‐CNN, respectively, all of which demonstrate the effectiveness and accuracy of the proposed method.

Adaptive rotation attention network for accurate defect detection on magnetic tile surface.

Defect detection on magnetic tile surfaces is of great significance for the production monitoring of permanent magnet motors. However, it is challenging to detect the surface defects from the magnetic tile due to these issues: 1) Defects appear randomly on the surface of the magnetic tile; 2) the defects are tiny and often overwhelmed by the background. To address such problems, an Adaptive Rotation Attention Network (ARA-Net) is proposed for defect detection on the magnetic tile surface, where the Adaptive Rotation Convolution (ARC) module is devised to capture the random defects on the magnetic tile surface by learning multi-view feature maps, and then the Rotation Region Attention (RAA) module is designed to locate the small defects from the complicated background by focusing more attention on the defect features. Experiments conducted on the MTSD3C6K dataset demonstrate the proposed ARA-Net outperforms the state-of-the-art methods, further providing assistance for permanent magnet motor monitoring.

Retracted: Magnetic Tile Surface Defect Detection Methodology Based on Self-Attention and Self-Supervised Learning.

[This retracts the article DOI: 10.1155/2022/3003810.].

Convolution With Rotation Invariance for Online Detection of Tiny Defects on Magnetic Tile Surface

Convolution With Rotation Invariance for Online Detection of Tiny Defects on Magnetic Tile Surface

MVRA-UNet: Multi-View Residual Attention U-Net for Precise Defect Segmentation on Magnetic Tile Surface

MVRA-UNet: Multi-View Residual Attention U-Net for Precise Defect Segmentation on Magnetic Tile Surface

Small Defect Detection Based on Local Structure Similarity for Magnetic Tile Surface

Surface defect detection is critical in manufacturing magnetic tiles to improve production yield. However, existing detection methods are difficult to use to accurately locate and segment small defects on magnetic tile images, because these defects always occupy extremely low proportions of images, and their visual features are difficult to identify, which means their feature representation for defect detection is quite weak. To address this issue, we propose an effective and feasible detection algorithm for small defects on magnetic tile surfaces. Firstly, based on local structure similarity of magnetic tile surfaces, the image is decomposed into low-rank and sparse matrices for estimating possible defect regions. To accurately locate defect areas while filtering out stains, textures, and noises, the sparse matrix is binarized and used for connected components analysis. Then, pixel values in the defect area are normalized, and the Retinex theory is applied to enhance the contrast between defects and background. Finally, an optimal threshold is determined by an automatic threshold segmentation method to segment the defect areas and edges precisely. Experimental results on a number of magnetic tile samples containing different types of defects demonstrated that the proposed algorithm outperforms the existing methods in terms of all evaluation metrics, showing broad industrial application prospects.

Novel industrial surface-defect detection using deep nested convolutional network with attention and guidance modules

Abstract Industrial defect inspection plays a crucial role in maintaining the high quality of the product. Although deep learning technologies have been applied to conduct automatic defect inspection, it is still difficult to detect industrial surface defects accurately due to complex variations. This study proposes a novel approach to industrial surface-defect detection that segments defect areas accurately and robustly from the complex background using a deep nested convolutional network (NC-Net) with attention and guidance modules. NC-Net consists of the encoder-decoder with nested residual U-blocks and feature enhancement modules. Each layer block of the encoder and decoder is also represented as a residual U-block. In addition, features are adaptively refined by applying the attention module to the skip connection between the encoder and decoder. Low-level encoder features are refined through edge guidance, and high-level encoder features through mask guidance, which can keep local and global contexts for accurate and robust defect detection. A comprehensive evaluation was conducted to verify the novelty and robustness of NC-Net using four datasets, including magnetic tile surface defects, steel surface defects, rail surface defects, and road surface defects. The proposed method outperformed previous state-of-the-art studies. An additional dataset was also evaluated to prove the extensibility and generality of the proposed approach.