Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots

Detecting defects in complex urban sewer scenes is crucial for urban underground structure health monitoring. However, most image-based sewer defect detection models are complex, have high resource consumption, and fail to provide detailed damage information. To increase defect detection efficiency,...

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Main Authors: Ruihao Liu, Zhongxi Shao, Qiang Sun, Zhenzhong Yu
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/24/23/7557
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author Ruihao Liu
Zhongxi Shao
Qiang Sun
Zhenzhong Yu
author_facet Ruihao Liu
Zhongxi Shao
Qiang Sun
Zhenzhong Yu
author_sort Ruihao Liu
collection DOAJ
description Detecting defects in complex urban sewer scenes is crucial for urban underground structure health monitoring. However, most image-based sewer defect detection models are complex, have high resource consumption, and fail to provide detailed damage information. To increase defect detection efficiency, visualize pipelines, and enable deployment on edge devices, this paper proposes a computer vision-based robotic defect detection framework for sewers. The framework encompasses positioning, defect detection, model deployment, 3D reconstruction, and the measurement of realistic pipelines. A lightweight Sewer-YOLO-Slim model is introduced, which reconstructs the YOLOv7-tiny network by adjusting its backbone, neck, and head. Channel pruning is applied to further reduce the model’s complexity. Additionally, a multiview reconstruction technique is employed to build a 3D model of the pipeline from images captured by the sewer robot, allowing for accurate measurements. The Sewer-YOLO-Slim model achieves reductions of 60.2%, 60.0%, and 65.9% in model size, parameters, and floating-point operations (FLOPs), respectively, while improving the mean average precision (mAP) by 1.5%, reaching 93.5%. Notably, the pruned model is only 4.9 MB in size. Comprehensive comparisons and analyses are conducted with 12 mainstream detection algorithms to validate the superiority of the proposed model. The model is deployed on edge devices with the aid of TensorRT for acceleration, and the detection speed reaches 15.3 ms per image. For a real section of the pipeline, the maximum measurement error of the 3D reconstruction model is 0.57 m. These results indicate that the proposed sewer inspection framework is effective, with the detection model exhibiting advanced performance in terms of accuracy, low computational demand, and real-time capability. The 3D modeling approach offers valuable insights for underground pipeline data visualization and defect measurement.
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spelling doaj-art-14ae1df7e8854d6c803dcc2f393ac86e2025-08-20T02:50:36ZengMDPI AGSensors1424-82202024-11-012423755710.3390/s24237557Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer RobotsRuihao Liu0Zhongxi Shao1Qiang Sun2Zhenzhong Yu3School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, ChinaHefei Intelligent Robot Institute, Hefei 230601, ChinaHefei Intelligent Robot Institute, Hefei 230601, ChinaDetecting defects in complex urban sewer scenes is crucial for urban underground structure health monitoring. However, most image-based sewer defect detection models are complex, have high resource consumption, and fail to provide detailed damage information. To increase defect detection efficiency, visualize pipelines, and enable deployment on edge devices, this paper proposes a computer vision-based robotic defect detection framework for sewers. The framework encompasses positioning, defect detection, model deployment, 3D reconstruction, and the measurement of realistic pipelines. A lightweight Sewer-YOLO-Slim model is introduced, which reconstructs the YOLOv7-tiny network by adjusting its backbone, neck, and head. Channel pruning is applied to further reduce the model’s complexity. Additionally, a multiview reconstruction technique is employed to build a 3D model of the pipeline from images captured by the sewer robot, allowing for accurate measurements. The Sewer-YOLO-Slim model achieves reductions of 60.2%, 60.0%, and 65.9% in model size, parameters, and floating-point operations (FLOPs), respectively, while improving the mean average precision (mAP) by 1.5%, reaching 93.5%. Notably, the pruned model is only 4.9 MB in size. Comprehensive comparisons and analyses are conducted with 12 mainstream detection algorithms to validate the superiority of the proposed model. The model is deployed on edge devices with the aid of TensorRT for acceleration, and the detection speed reaches 15.3 ms per image. For a real section of the pipeline, the maximum measurement error of the 3D reconstruction model is 0.57 m. These results indicate that the proposed sewer inspection framework is effective, with the detection model exhibiting advanced performance in terms of accuracy, low computational demand, and real-time capability. The 3D modeling approach offers valuable insights for underground pipeline data visualization and defect measurement.https://www.mdpi.com/1424-8220/24/23/7557urban pipelinedefect detectionYOLO networklightweightedge deployment3D reconstruction
spellingShingle Ruihao Liu
Zhongxi Shao
Qiang Sun
Zhenzhong Yu
Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
Sensors
urban pipeline
defect detection
YOLO network
lightweight
edge deployment
3D reconstruction
title Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
title_full Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
title_fullStr Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
title_full_unstemmed Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
title_short Defect Detection and 3D Reconstruction of Complex Urban Underground Pipeline Scenes for Sewer Robots
title_sort defect detection and 3d reconstruction of complex urban underground pipeline scenes for sewer robots
topic urban pipeline
defect detection
YOLO network
lightweight
edge deployment
3D reconstruction
url https://www.mdpi.com/1424-8220/24/23/7557
work_keys_str_mv AT ruihaoliu defectdetectionand3dreconstructionofcomplexurbanundergroundpipelinescenesforsewerrobots
AT zhongxishao defectdetectionand3dreconstructionofcomplexurbanundergroundpipelinescenesforsewerrobots
AT qiangsun defectdetectionand3dreconstructionofcomplexurbanundergroundpipelinescenesforsewerrobots
AT zhenzhongyu defectdetectionand3dreconstructionofcomplexurbanundergroundpipelinescenesforsewerrobots