Crack Segments Research Articles

Multimodal Fusion Network for Crack Segmentation with Modified U-Net and Transfer Learning–Based MobileNetV2

Multimodal Fusion Network for Crack Segmentation with Modified U-Net and Transfer Learning–Based MobileNetV2

An ultra-lightweight network combining Mamba and frequency-domain feature extraction for pavement tiny-crack segmentation

Pixel-level detection and segmentation of pavement cracks is a crucial but challenging task. Current deep learning methods mainly target larger cracks, often overlooking tiny cracks. Additionally, improvements in these methods typically involve more complex network structures, leading to reduced efficiency and higher computational demands. To tackle these challenges, we propose an Ultra-lightweight Network (ULNet) designed for tiny crack segmentation. ULNet boasts a low parameter count and minimal FLOPs, comprising three main components: the Mamba feature extraction branch, the frequency domain feature extraction branch, and the feature decoder. The Mamba feature extraction branch utilizes the proposed cross-visual Mamba feature extraction module, which enhances the accuracy of tiny crack detection by extracting global features through layer-by-layer processing and cross-fusion of feature information, all without relying on an attention mechanism. The frequency domain feature extraction branch transforms input features into the frequency domain and applies a Gaussian high-pass filter to smooth the image and extract high-frequency crack details while suppressing noise. Finally, the feature decoder incorporates a multi-scale feature selection and fusion module that integrates both channel and spatial attention, enabling effective extraction of tiny crack features from adjacent scales. Inspired by the mechanisms of biological visual information processing, we integrate the high-frequency features from the frequency domain feature extraction branch with the features from the Mamba feature extraction branch. This integration follows the interactive patterns of biological vision, allowing for layer-wise fusion and interaction of features, thereby supplementing the information from the Mamba branch and reducing information loss. We tested and evaluated ULNet on several public datasets (BJN260, Rain365, Sun520, and DeepCrack). Experimental results indicate that our method achieves state-of-the-art performance among all lightweight approaches.

GAF-Net: A new automated segmentation method based on multiscale feature fusion and feedback module

Surface defect detection (SDD) is the necessary technique to monitor the surface quality of production. However, fine grain defects caused by stress loading, environmental influences, and construction defects is still a challenge to detect. In this research, the convolutional neural network for crack segmentation is developed based on the feature fusion and feedback on the global features and multi-scale feature (GAF-Net). First, a multi-scale feature feedback module (MSFF) is proposed, which uses four different scales to refine local features by fusing high-level and sub-high-level features to perform feedback correction. Secondly, the global feature module (GF) is proposed to generate a fine global information map using local features and adaptive weighted fusion with the correction map for crack detection. Finally, the GAF-Net network with multi-level feature maps is deeply supervised to accelerate GAF-Net and improve the detection accuracy. GAF-Net is trained and experimented on three publicly available pavement crack datasets, and the results show that GAF-Net achieves state-of-the-art results in the IoU segmentation metrics when compared to other deep learning methods (Crackforest: 53.61 %; Crack500: 65.19 %; DeepCrack: 81.63 %).

DCUFormer: Enhancing pavement crack segmentation in complex environments with dual-cross/upsampling attention

Efficient road inspection and maintenance are essential to extend pavement lifespan and enhance safety. However, automated crack detection remains challenging due to varied environmental conditions and differences in image collection equipment, making robust algorithm development a critical need. Vision Transformers, with their capacity to capture long-range dependencies, offer significant advantages for crack detection in complex scenarios by effectively extracting global features. Nevertheless, existing Transformer-based methods encounter difficulties in boundary delineation due to decoder design limitations, which lead to suboptimal fusion of low-level and high-level features. To address this issue, we propose a comprehensive approach that integrates semantic preservation, detail refinement, and detail delineation. These concepts are realized through our novel Dual-Cross Attention Module (DCA) and Upsampling Attention Module (UA). The DCA module progressively filters redundant details from low-level feature layers using high-level semantic information, while preserving boundary details to refine high-level feature boundaries. In addition, the UA module employs progressive local cross-attention in upsampling, facilitating more precise boundary definitions and surpassing conventional dynamic upsampling methods. Our approach, utilizing both lightweight (MiT-B0, LVT) and middle-weight (Swin-T) backbones, demonstrates state-of-the-art performance on three diverse datasets—Crack500, CrackSC, and UAV-Crack500—highlighting its robustness across varied conditions. This work contributes to advancing Transformer-based architectures for defect segmentation in complex engineering contexts, underscoring the critical role of improved feature fusion in crack detection. The code is available at: https://github.com/SHAN-JH/DCUFormer.

3D Pixelwise damage mapping using a deep attention based modified Nerfacto

Recent advancements in structural health monitoring have highlighted the necessity for accurate three-dimensional (3D) damage mapping on digital twins, moving beyond traditional methods such as photogrammetry, which frequently struggle to capture intricate planar surfaces. To address this limitation, this paper proposes a new advanced 3D reconstruction method and its integration with 3D damage mapping techniques. As the 3D reconstruction method, an Attention-based Modified Nerfacto (ABM-Nerfacto) model is developed, and is integrated with an advanced damage segmentation method. Using a three-span continuous bridge with concrete piers as an example structure, and concrete cracks as the example damage, the state-of-the-art STRNet is utilized for crack segmentation. Through extensive parametric studies and comparative evaluations, the proposed ABM-Nerfacto model was demonstrated to produce high-quality 3D reconstructions and corresponding damage mappings for this bridge system. This integrated approach provides a promising solution for comprehensive 3D digital twin-based structural health monitoring.

A Novel Multi-Scale Feature Enhancement U-Shaped Network for Pixel-Level Road Crack Segmentation

Timely and accurate detection of pavement cracks, the most common type of road damage, is essential for ensuring road safety. Automatic image segmentation of cracks can accurately locate their pixel positions. This paper proposes a Multi-Scale Feature Enhanced U-shaped Network (MFE-UNet) for pavement crack detection. This network model uses a Residual Detail-Enhanced Block (RDEB) instead of a conventional convolution in the encoder–decoder process. The block combines Efficient Multi-Scale Attention to enhance its feature extraction performance. The Multi-Scale Gating Feature Fusion (MGFF) is incorporated into the skip connections, enhancing the fusion of multi-scale features to capture finer crack details while maintaining rich semantic information. Furthermore, we created a pavement crack image dataset named China_MCrack, consisting of 1500 images collected from road surfaces using smartphone-mounted motorbikes. The proposed network was trained and tested on the China_MCrack, DeepCrack, and Crack-Forest datasets, with additional generalization experiments on the BochumCrackDataset. The results were compared with those of the U-Net model, ResUNet, and Attention U-Net. The experimental results show that the proposed MFE-UNet model achieves accuracies of 82.95%, 91.71%, and 69.02% on three datasets, namely, China_MCrack, DeepCrack, and Crack-Forest datasets, respectively, and the F1_score is improved by 1–4% compared with other networks. Experimental results demonstrate that the proposed method is effective in detecting cracks at the pixel level.

Uncertainty quantification for a deep learning models for image-based crack segmentation

Uncertainty quantification for a deep learning models for image-based crack segmentation

Thermographic evaluation of cracks of different formats in rendered facades

The crack is the most frequently occurring anomaly and one that attributes greater severity to rendered walls. Cracks can be investigated using infrared thermography since defects on a surface have different temperatures in relation to the region without a defect. Depending on the cause, cracks can have different formats, with linear and ramified ones being more common. Because the cracks have different formats, we evaluated the possibility of investigating and assigning severity to the cracks according to their format, using thermography, during heating and cooling. We observed the evolution of the temperature in the heating and cooling of mortar plates with linear and ramified cracks with different dimensions (width and depth). The objective was to identify the trends of evolution and Delta-T values obtained from heating and cooling depending on the format of the crack. The evolution of the temperature of the plates was monitored, during heating and cooling, using thermograms, in which the evolution of the Delta-T was identified and the method for evaluating the cracks was established. The investigation using thermography indicated that linear and ramified cracks have the same trend of evolution as Delta-T, in which the higher values, in absolute value, are associated with larger crack dimensions. Linear cracks have higher Delta-T, in absolute value, than ramified cracks, and this difference is better identified in the cooling cycle. The increase in temperature by the cracks and regions without defects are dependent on each other, thus indicating that the greater number of crack segments favors the heat flow and the reduction of Delta-T values.

A novel deep learning‐based technique for efficient characterization of engineered cementitious composites cracks for durability assessment

AbstractEngineered Cementitious Composites also known as Strain‐hardening cementitious composites (SHCCs) has unique cracking patterns like cracks that have tiny widths and showcase high density. All of this makes it difficult and laborious to compute crack parameters from crack patterns. Unfortunately, this is an essential part of assessing durability and micromechanical modeling. SHSnet is developed to perform end‐to‐end semantic segmentation of SHCC cracks. SHSnet is efficient, attention based deep encoder‐decoder network with large receptive field. Loss function based on Tversky function were used for training the model. SHSnet with loss function shows promising result with mPrecision, mF1Score and mIoU of 0.87, 0.84 and 0.83 respectively for complex SHCC cracks while requiring at least an order of fewer computational parameters than those in the literature. An image processing unit is then used to estimate the width, number, and length of the cracks from the segmentation mask. Test results show that the computed crack parameters with SHSnet are exactly the same as that computed with an optical microscope but require ~100× less time. Results demonstrate that SHSnet works equally well in SHCCs with different surface textures, crack density, and widths; the final result was far superior to a conventional technique. This technique also shows promising results in an automatic evaluation of crack parameters relevant to durability and visualizing crack patterns even in the presence of artifacts during progressive testing. The results also demonstrate the necessity to accurately and densely calculate crack length and maximum crack width; else the durability results are expected to be significantly more conservative than the actual value.

Robust pavement crack segmentation network based on transformer and dual-branch decoder

The application of deep learning techniques for semantic segmentation of crack images has become a significant research direction in road maintenance and safety. Despite the extensive research in recent years on semantic segmentation algorithms based on convolutional neural networks, their relatively small actual receptive fields cannot effectively handle long and fine pavement cracks. In contrast, transformer-based models can effectively utilize contextual semantic information. Therefore, a robust pavement crack segmentation network, CSTF, is proposed based on the Swin Transformer encoder. Within CSTF, a feature pyramid pooling module is introduced to provide global priors, and a dual-branch decoder is designed to preserve and learn semantic information, enabling CSTF to handle large-scale images and wide-spanning cracks. The results demonstrate that CSTF achieved an mIoU of 0.813 and 22.97 FPS on the large-scale dataset constructed in this study, enabling high-precision real-time detection. Moreover, it exhibits robustness against common interfering patterns like striped patches or other disturbances found in pavement crack images.

Pavement crack detection based on depth-supervision FRRN model

Timely detection of early pavement distress is crucial for effective pavement maintenance. A promising approach involves the segmenting the road surface cracks area from its images. However, the previously employed full-resolution residual network (FRRN), when employing a large number of full-resolution residual units (FRRUs), is susceptible to challenges such as exploding and vanishing gradients. Addressing these issues, this paper has introduced a depth supervision mechanism into FRRN, leading to the development of the Depth Supervision FRRN (DSFRRN) model, designed specifically for accurate segmentation of cracks in road images. This model enhances nonlinear expressiveness while retaining essential features, achieving high precision in pavement crack segmentation. Through experimental validation using a dataset comprising 1565 images of damaged pavements, the result demonstrate that DSFRRN outperforms the original FRRN in terms of both F1 score and Jaccard index, accurately delineating cracks. Consequently, the automated pavement damage detection method presented herein facilitates cost-effective and efficient pavement inspection, contributing to the safeguarding of roadway surfaces and transportation infrastructure.

Fatigue Crack Segmentation and Characterization of Additively Manufactured Ti‐6Al‐4V Using X‐Ray Computed Tomography

ABSTRACTX‐ray computed tomography (XCT) is extremely useful for the non‐destructive analysis of additively manufactured (AM) components. AM components often show manufacturing defects such as lack‐of‐fusion (LoF), which are detrimental to the fatigue life of components. To better understand how cracks initiate and propagate from internal defects, we fabricated Ti‐6Al‐4V samples with an internal cavity using electron beam powder bed fusion. The samples were tested in high‐cycle and very high‐cycle fatigue regimes. XCT was used to locate crack initiation sites and to determine characteristic properties of cracks and defects with the aid of deep learning segmentation. LoF defects exposed to the outer surface of the samples after machining were found to be as detrimental to fatigue life as the internal artificial defects. This work can benefit industries that utilize the AM of high‐strength, lightweight alloys, in the design and manufacturing of components to improve part reliability and fatigue life.

Topology-aware mamba for crack segmentation in structures

CrackMamba, a Mamba-based model, is designed for efficient and accurate crack segmentation for monitoring the structural health of infrastructure. Traditional Convolutional Neural Network (CNN) models struggle with limited receptive fields, and while Vision Transformers (ViT) improve segmentation accuracy, they are computationally intensive. CrackMamba addresses these challenges by utilizing the VMambaV2 with pre-trained ImageNet-1 k weights as the encoder and a newly designed decoder for better performance. To handle the random and complex nature of crack development, a Snake Scan module is proposed to reshape crack feature sequences, enhancing feature extraction. Additionally, the three-branch Snake Conv VSS (SCVSS) block is proposed to target cracks more effectively. Experiments show that CrackMamba achieves state-of-the-art (SOTA) performance on the CrackSeg9k and SewerCrack datasets, and demonstrates competitive performance on the retinal vessel segmentation dataset CHASE_DB1, highlighting its generalization capability.

Dadnet: dual-attention detection network for crack segmentation on tomb murals

Many tomb murals have punctate losses, cracks, and craquelure due to underground subsidence and changes in their physical support. Visual non-destructive detection techniques enable rapid assessment of how much tomb murals are affected by cracking, providing suggestions for their conservation. However, tomb murals are typically created by sketching outlines and then colored. Detailed sketches can easily interfere with crack detection work, requiring the use of deep learning network to better learn crack features and improve detection accuracy. At the same time the limited data of tomb mural presents a challenge to build a deep learning network. To address these issues, this paper introduces a novel dual-attention detection network (DADNet) for crack segmentation of tomb murals. In this work, a customized dataset is first constructed by collecting mural images from the Tang Dynasty tombs. Then the ConvNeXt framework serves as the basis for feature extraction, enhancing the process. Lastly, a dual-attention module utilizing neighborhood attention and biaxial attention is employed to accurately identify the crack regions. Neighborhood attention performs a local self-attention operation around the pixel point, addressing the limitations of self-attention. This approach significantly reduces computational demands as the image size increases. Biaxial attention performs attention calculations in the horizontal and vertical directions. This compensates for the limitation of neighborhood attention in capturing global dependencies. Our DADNet outperformed the competing methods, achieving the highest recorded scores of 78.95% for MIoU and 61.05% for the Jaccard index.

Quantifying sandstone crack extension and expansion via deep learning methods

This study investigates the damage evolution of sandstone under loading stresses, which can lead to irreversible plastic deformation and reduced project stability service life. To achieve this objective, we identify and quantify the emergence and expansion process of sandstone cracks using deep learning methods. Specifically, our approach employs a crack segmentation model enhanced by an attention mechanism, achieving a remarkable effective crack detection MIoU of 93.38. Through the application of connectivity domain analysis, skeleton extraction, and orthogonal projection techniques, we extract crucial crack parameters, which are subsequently formulated into equations to determine their actual dimensions. These evolving parameter variations serve as the foundation for predicting the sandstone's entire damage progression, encompassing both microscopic crack growth and eventual catastrophic failure preceding macroscopic manifestation of damage. Validation of our method through uniaxial compression tests on sandstone specimens confirm its efficacy and practical applicability. In conclusion, this study presents a novel framework for quantifying sandstone crack evolution, providing invaluable insights into the intricate mechanisms governing damage fracture progression in rocks.

Quantitative assessment of cracks in concrete structures using active-learning-integrated transformer and unmanned robotic platform

Quantitative assessment of cracks in concrete bridges is crucial for structural health monitoring and digital twin. However, the training of crack segmentation models relies heavily on annotation resources, and their segmentation capabilities are often unsatisfactory in terms of the accuracy of boundary location of thin cracks encountered in practice. In this paper, an active-learning-integrated crack segmentation transformer (ACS-Former) framework is proposed to maximize segmentation performance with limited annotation resources. The two-branch ACS-Former includes (1) a feature pyramid transformer (FPT) for multi-scale crack segmentation and (2) boundary difficulty-aware active learning (BDAL) to select informative images for labeling and incorporation into FPT training. Additionally, an adhesive climbing robot is proposed for image collection of hard-to-access components of large bridges. The on-site operational feasibility and practicability of the proposed ACS-Former and climbing robot are demonstrated by field experiments performed on in-service bridges, including the quantification of cracks narrower than 0.2 mm, as required by engineering codes.

Generative AI-Driven Data Augmentation for Crack Detection in Physical Structures

The accurate segmentation of cracks in structural materials is crucial for assessing the safety and durability of infrastructure. Although conventional segmentation models based on deep learning techniques have shown impressive detection capabilities in these tasks, their performance can be restricted by small amounts of training data. Data augmentation techniques have been proposed to mitigate the data availability issue; however, these systems often have limitations in texture diversity, scalability over multiple physical structures, and the need for manual annotation. In this paper, a novel generative artificial intelligence (GAI)-driven data augmentation framework is proposed to overcome these limitations by integrating a projected generative adversarial network (ProjectedGAN) and a multi-crack texture transfer generative adversarial network (MCT2GAN). Additionally, a novel metric is proposed to evaluate the quality of the generated data. The proposed method is evaluated using three datasets: the bridge crack library (BCL), DeepCrack, and Volker. From the simulation results, it is confirmed that the segmentation performance can be improved by the proposed method in terms of intersection over union (IoU) and Dice scores across three datasets.

Crack SAM: enhancing crack detection utilizing foundation models and Detectron2 architecture

Accurate crack detection is crucial for maintaining pavement integrity, yet manual inspections remain labor-intensive and prone to errors, underscoring the need for automated solutions. This study proposes a novel crack segmentation approach utilizing advanced visual models, specifically Detectron2 and the Segment Anything Model (SAM), applied to the CFD and Crack500 datasets, which exhibit intricate and diverse crack patterns. Detectron2 was tested with four configurations—mask_rcnn_R_50_FPN_3x, mask_rcnn_R_101_FPN_3x, faster_rcnn_R_50_FPN_3x, and faster_rcnn_R_101_FPN_3x—while SAM was compared using Focal Loss, DiceCELoss, and DiceFocalLoss. SAM with DiceFocalLoss outperformed Detectron2, achieving mean IoU scores of 0.69 and 0.59 on the CFD and Crack500 datasets, respectively. The integration of Detectron2 with faster_rcnn_R_101_FPN_3x and SAM using DiceFocalLoss involves generating bounding boxes with Detectron2, which serve as prompts for SAM to produce segmentation masks. This approach achieves mIoU scores of 0.83 for CFD dataset and 0.75 for Crack500 dataset. These results highlight the potential of combining foundation models with Detectron2 for advancing crack detection technologies, offering valuable insights for enhancing highway maintenance systems.

Computer vision-based cascade detection of peeling and cracking in masonry house walls

Self-built masonry structures are commonly used as houses in rural areas of the central plains of China. These structures pose significant safety risks due to the low level of self-building and non-standard designs. The primary type of damage to the walls of masonry houses is cracks, while the decorative layers of the walls may also experience peeling or cracking. The shapes, sizes, and surface characteristics of these damages are complex and unique to each type. To achieve fast identification of surface damage on masonry house walls, this paper proposes a cascade detection model that combines a multilevel cascade classifier with a parallel sub-segmentation network. The VGG16 neural network is used as the backbone for a multi-level series classifier. The model is trained by using a damage image set of the wall decorative layers in rural masonry houses. The classification of background and damage, as well as the classification of cracks and peels, are sequentially completed. Then, the parallel sub-segmentation model uses EfficientNet-B7 as the encoder and combines it with the U-Net framework skeleton to perform pixel-level segmentation of peeling and cracks. Finally, the output of parallel sub-segmentation networks is superimposed and fused to generate a complete image containing segmentation information of peeling and cracks. The cascade form network structure adopted in this model significantly reduces the training difficulty and enhances the model accuracy. Compared with Segformer and Deeplabv3+ network, the average IoU of the proposed method for on-site masonry wall images can be increased by 0.29 and 0.08, respectively.

Lightweight decoder U-net crack segmentation network based on depthwise separable convolution

Lightweight decoder U-net crack segmentation network based on depthwise separable convolution