scholarly journals An Automatic Concrete Crack-Detection Method Fusing Point Clouds and Images Based on Improved Otsu’s Algorithm

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1581
Author(s):  
Xiaolong Chen ◽  
Jian Li ◽  
Shuowen Huang ◽  
Hao Cui ◽  
Peirong Liu ◽  
...  
Keyword(s):  
Crack Detection ◽  
Detection Method ◽  
Multiple Scales ◽  
Point Clouds ◽  
Depth Image ◽  
Detection Accuracy ◽  
Detection Techniques ◽  
Concrete Crack ◽  
3D Point Clouds ◽  
2D Images

Cracks are one of the main distresses that occur on concrete surfaces. Traditional methods for detecting cracks based on two-dimensional (2D) images can be hampered by stains, shadows, and other artifacts, while various three-dimensional (3D) crack-detection techniques, using point clouds, are less affected in this regard but are limited by the measurement accuracy of the 3D laser scanner. In this study, we propose an automatic crack-detection method that fuses 3D point clouds and 2D images based on an improved Otsu algorithm, which consists of the following four major procedures. First, a high-precision registration of a depth image projected from 3D point clouds and 2D images is performed. Second, pixel-level image fusion is performed, which fuses the depth and gray information. Third, a rough crack image is obtained from the fusion image using the improved Otsu method. Finally, the connected domain labeling and morphological methods are used to finely extract the cracks. Experimentally, the proposed method was tested at multiple scales and with various types of concrete crack. The results demonstrate that the proposed method can achieve an average precision of 89.0%, recall of 84.8%, and F1 score of 86.7%, performing significantly better than the single image (average F1 score of 67.6%) and single point cloud (average F1 score of 76.0%) methods. Accordingly, the proposed method has high detection accuracy and universality, indicating its wide potential application as an automatic method for concrete-crack detection.

Concrete crack detection method based on optical fiber sensing network and microbending principle

2019 ◽  
Vol 117 ◽  
pp. 299-304 ◽  
Author(s):  
Chunfeng Wu ◽  
Kaike Sun ◽  
Yuming Xu ◽  
Sheng Zhang ◽  
Xun Huang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Crack Detection ◽  
Detection Method ◽  
Fiber Sensing ◽  
Concrete Crack ◽  
Optical Fiber Sensing

Fast concrete crack detection method via L2 sparse representation

2018 ◽  
Vol 54 (12) ◽  
pp. 752-754 ◽  
Author(s):  
Baoxian Wang ◽  
Quanle Zhang ◽  
Weigang Zhao
Keyword(s):  
Sparse Representation ◽  
Crack Detection ◽  
Detection Method ◽  
Concrete Crack

scholarly journals Shape distribution features for point cloud analysis – a geometric histogram approach on multiple scales

2014 ◽  
Vol II-3 ◽  
pp. 9-16 ◽  
Author(s):  
R. Blomley ◽  
M. Weinmann ◽  
J. Leitloff ◽  
B. Jutzi
Keyword(s):  
Laser Scanning ◽  
Multiple Scales ◽  
Point Clouds ◽  
Full Potential ◽  
Shape Distribution ◽  
3D Point Clouds ◽  
Distribution Features ◽  
Reliable Performance ◽  
Scale Range ◽  
Wide Scale

Due to ever more efficient and accurate laser scanning technologies, the analysis of 3D point clouds has become an important task in modern photogrammetry and remote sensing. To exploit the full potential of such data for structural analysis and object detection, reliable geometric features are of crucial importance. Since multiscale approaches have proved very successful for image-based applications, efforts are currently made to apply similar approaches on 3D point clouds. In this paper we analyse common geometric <i>covariance</i> features, pinpointing some severe limitations regarding their performance on varying scales. Instead, we propose a different feature type based on <i>shape distributions</i> known from object recognition. These novel features show a very reliable performance on a wide scale range and their results in classification outnumber <i>covariance</i> features in all tested cases.

scholarly journals Optimized EEG–fNIRS Based Mental Workload Detection Method for Practical Applications

2021 ◽  
Author(s):  
Hongzuo Chu ◽  
Yong Cao ◽  
Jin Jiang ◽  
Jiehong Yang ◽  
Mengyin Huang ◽  
...  
Keyword(s):  
Task Difficulty ◽  
Detection Method ◽  
Mental Workload ◽  
Systems Design ◽  
Detection Methods ◽  
Complex Signal ◽  
Detection Accuracy ◽  
Signal Acquisition ◽  
Detection Techniques ◽  
Channel Configuration

Abstract Background: Mental workload is a critical consideration in complex man–machine systems design. Among various mental workload detection techniques, multimodal detection techniques integrating EEG and fNIRS signals have attracted considerable attention. However, existing EEG–fNIRS-based mental workload detection methods have certain defects, such as complex signal acquisition channels and low detection accuracy, which restrict their practical application.Method: The signal acquisition configuration was optimized and a more accurate and convenient EEG–fNIRS-based mental workload detection method was constructed. A classical MATB task was conducted with 20 participating volunteers. Subjective scale data, 64-channel EEG data, and two-channel fNIRS data were collected.Results: A higher number of EEG channels correspond to higher detection accuracy. However, there is no obvious improvement in accuracy once the number of EEG channels reaches 26, with a four-level mental workload detection accuracy of 78.25±4.71%. Partial results of physiological analysis verify the results of previous studies, such as that the θ power of EEG and concentration of O2Hb in the prefrontal region increase while the concentration of HHb decreases with task difficulty. It was further observed, for the first time, that the energy of each band of EEG signals was significantly different in the occipital lobe region, and the power of 𝛽1 and 𝛽2 bands in the occipital region increased significantly with task difficulty. The changing range and the mean amplitude of O2Hb in high-difficulty tasks were significantly higher compared with those in low-difficulty tasks.Conclusions: The channel configuration of EEG–fNIRS-based mental workload detection was optimized to 26 EEG channels and two frontal fNIRS channels. A four-level mental workload detection accuracy of 78.25±4.71% was obtained, which is higher than previously reported results. The proposed configuration can promote the application of mental workload detection technology in military, driving, and other complex human–computer interaction systems.

scholarly journals 3D Shape Completion with Multi-View Consistent Inference

2020 ◽  
Vol 34 (07) ◽  
pp. 10997-11004 ◽  
Author(s):  
Tao Hu ◽  
Zhizhong Han ◽  
Matthias Zwicker
Keyword(s):  
Point Clouds ◽  
Shape Descriptor ◽  
Depth Image ◽  
Regularization Term ◽  
3D Shape ◽  
Depth Images ◽  
3D Point Clouds ◽  
Geometric Consistency ◽  
Shape Completion ◽  
Data Term

3D shape completion is important to enable machines to perceive the complete geometry of objects from partial observations. To address this problem, view-based methods have been presented. These methods represent shapes as multiple depth images, which can be back-projected to yield corresponding 3D point clouds, and they perform shape completion by learning to complete each depth image using neural networks. While view-based methods lead to state-of-the-art results, they currently do not enforce geometric consistency among the completed views during the inference stage. To resolve this issue, we propose a multi-view consistent inference technique for 3D shape completion, which we express as an energy minimization problem including a data term and a regularization term. We formulate the regularization term as a consistency loss that encourages geometric consistency among multiple views, while the data term guarantees that the optimized views do not drift away too much from a learned shape descriptor. Experimental results demonstrate that our method completes shapes more accurately than previous techniques.

scholarly journals Deep Learning-Based Feature Silencing for Accurate Concrete Crack Detection

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4403
Author(s):  
Umme Hafsa Billah ◽  
Hung Manh La ◽  
Alireza Tavakkoli
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Network Architecture ◽  
Crack Detection ◽  
Inspection System ◽  
Detection Accuracy ◽  
Feature Maps ◽  
Neural Network Architecture ◽  
Concrete Crack ◽  
Discriminative Feature

An autonomous concrete crack inspection system is necessary for preventing hazardous incidents arising from deteriorated concrete surfaces. In this paper, we present a concrete crack detection framework to aid the process of automated inspection. The proposed approach employs a deep convolutional neural network architecture for crack segmentation, while addressing the effect of gradient vanishing problem. A feature silencing module is incorporated in the proposed framework, capable of eliminating non-discriminative feature maps from the network to improve performance. Experimental results support the benefit of incorporating feature silencing within a convolutional neural network architecture for improving the network’s robustness, sensitivity, and specificity. An added benefit of the proposed architecture is its ability to accommodate for the trade-off between specificity (positive class detection accuracy) and sensitivity (negative class detection accuracy) with respect to the target application. Furthermore, the proposed framework achieves a high precision rate and processing time than the state-of-the-art crack detection architectures.

Research on Bolt Crack Detection Method Based on Image Processing

2013 ◽  
Vol 433-435 ◽  
pp. 426-429
Author(s):  
Jin Qiu Liu ◽  
Bing Fa Zhang ◽  
Yu Zeng Wang ◽  
Guang Ya Li ◽  
Jing Ru Han
Keyword(s):  
Image Processing ◽  
Edge Detection ◽  
Image Recognition ◽  
Crack Detection ◽  
Detection Method ◽  
Image Acquisition ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Contact Detection ◽  
Fracture Identification

A method of non-contact detection of bolt fracture have serial steps as follows: First of all the required data is obtained through image acquisition, then through the edge detection, image recognition and other image processing on the image to get the bolt fracture identification results, finally the non-contact measurement bolt fracture is realized. Experiments show that bolt crack detection method based on image processing, compared with the traditional detection methods improve the efficiency of detection and improve the detection accuracy. The method for bolt crack detection is feasible.

scholarly journals Automatic 3D Landmark Extraction System Based on an Encoder–Decoder Using Fusion of Vision and LiDAR

2020 ◽  
Vol 12 (7) ◽  
pp. 1142
Author(s):  
Jeonghoon Kwak ◽  
Yunsick Sung
Keyword(s):  
Point Cloud ◽  
Point Clouds ◽  
Depth Image ◽  
3D Point Cloud ◽  
Digital World ◽  
Depth Images ◽  
3D Point Clouds ◽  
Rgb Images ◽  
Rgb Image ◽  
3D Landmarks

To provide a realistic environment for remote sensing applications, point clouds are used to realize a three-dimensional (3D) digital world for the user. Motion recognition of objects, e.g., humans, is required to provide realistic experiences in the 3D digital world. To recognize a user’s motions, 3D landmarks are provided by analyzing a 3D point cloud collected through a light detection and ranging (LiDAR) system or a red green blue (RGB) image collected visually. However, manual supervision is required to extract 3D landmarks as to whether they originate from the RGB image or the 3D point cloud. Thus, there is a need for a method for extracting 3D landmarks without manual supervision. Herein, an RGB image and a 3D point cloud are used to extract 3D landmarks. The 3D point cloud is utilized as the relative distance between a LiDAR and a user. Because it cannot contain all information the user’s entire body due to disparities, it cannot generate a dense depth image that provides the boundary of user’s body. Therefore, up-sampling is performed to increase the density of the depth image generated based on the 3D point cloud; the density depends on the 3D point cloud. This paper proposes a system for extracting 3D landmarks using 3D point clouds and RGB images without manual supervision. A depth image provides the boundary of a user’s motion and is generated by using 3D point cloud and RGB image collected by a LiDAR and an RGB camera, respectively. To extract 3D landmarks automatically, an encoder–decoder model is trained with the generated depth images, and the RGB images and 3D landmarks are extracted from these images with the trained encoder model. The method of extracting 3D landmarks using RGB depth (RGBD) images was verified experimentally, and 3D landmarks were extracted to evaluate the user’s motions with RGBD images. In this manner, landmarks could be extracted according to the user’s motions, rather than by extracting them using the RGB images. The depth images generated by the proposed method were 1.832 times denser than the up-sampling-based depth images generated with bilateral filtering.

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