An Electronically Stabilized Multi-Color Multi-Ring Structured Light Sensor for Gas Pipelines Internal Surface Inspection

Alzuhiri, Mohand; Farrag, Khalid; Lever, Ernest; Deng, Yiming

doi:10.1109/jsen.2021.3086415

Cited by 14 publications

(5 citation statements)

References 23 publications

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“…More recently, omnidirectional vision sensors have gained popularity because of the FOV of 360 • and quantity of visual information they provide the pipeline robot with. Related researched mainly focus on the realization of wide FOV [22,23], defect detection algorithm [24][25][26] and robot pose estimation [27]. The detection accuracy and efficiency of methods based on deep learning are far higher than that of the traditional methods.…”

Section: Related Workmentioning

confidence: 99%

Design of hexapod robot equipped with omnidirectional vision sensor for defect inspection of pipeline’s inner surface

Guo,

Liu,

Zhou

et al. 2024

Meas. Sci. Technol.

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Defect detection of inner surface of precision pipes is a crucial aspect of ensuring production safety. Currently, pipeline defect detection primarily relies on recording video for manual recognition, with urgent need to improve automation, quantification and accuracy. This paper presents a hexapod in-pipe robot with carrying capacity designed to transport the omnidirectional vision sensor to specified location within unreachable pipelines. The feasibility of the robot’s mechanical design and sensor load-carrying module is analyzed using theory calculations, motion simulations and finite element method. To address the challenges of small pixel ratio and weak background changes in panoramic images, a tiny defect segmentor (TDS) based on ResNet is proposed for detecting tiny defects on the inner surface of pipelines. The hardware and software systems are implemented, and the motion performance of the pipeline robot is validated through experiments. The results demonstrate that the robot achieves stable movement at a speed of over 0.1m/s and can adapt to pipe diameter ranging from of 110 to 130 mm. The novelty of the robot lies in providing stable control of the loaded vision sensor, with control precision of the rotation angle and the displacement recorded at 1.84% and 0.87%, respectively. Furthermore, the proposed method achieves a detection accuracy of 95.67% for tiny defects with a diameter less than 3 mm and provides defect location information. This pipeline robot serves as an essential reference for development of in-pipe 3D vision inspection system.

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Section: Related Workmentioning

confidence: 99%

Design of hexapod robot equipped with omnidirectional vision sensor for defect inspection of pipeline’s inner surface

Guo,

Liu,

Zhou

et al. 2024

Meas. Sci. Technol.

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show abstract

“…In our group, we proposed a novel multi-ring beam sensing system in which multi-ring structured light is evenly distributed along the axis, and the cross-sectional profiles of the inner surface to be measured can be obtained in a single exposure [24]. Compared with a single-ring system, the multi-ring system demonstrates higher efficiency and capability to correct for the inclination of the sensor axis relative to the tested pipeline, obviating the need for strict alignment between the measurement system and the object [25]. Nevertheless, more in-depth works are required to enhance the measurement accuracy of multi-ring system.…”

Section: Introductionmentioning

confidence: 99%

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Li,

Deng,

et al. 2024

Meas. Sci. Technol.

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Parts with a large depth-to-diameter ratio play a critical role in the military, aerospace, and automotive industries. However, accurately measuring their inner surface profile remians challenging owing to the lack of adequate and accurate sensors. We developed a multi-ring structured light system to obtain three-dimensional data of inner contours, such as inner diameters, which are crucial for ensuring component performance and safety. In this study, we proposed three simple yet effective techniques to improve the multi-ring beam structured measurement system. First, we designed a distortion correction method to calibrate the imaging system. Second, a two-step calibration approach was used to calibrate the multi-ring projection. Meanwhile, we benchmarked the effects of different light sources on image speckles. The calibration results demonstrated that the coefficient of determination (R-2) used for line fitting exceeded 0.999. Moreover, the measurement experimental results show that the uncertainty of less than 10 µm and the smallest measurable pipe inner diameter can reach 15 mm, demonstrating that our methods are promising for improving the accuracy of structured light optical sensing systems. This system satisfies the measurement requirements and can be immediately utilized to meet the high demand for inner contour measurements in industrial applications.

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“…These methods are inefficient and cannot be used for a quantitative analysis of measurement results. In recent years, the rapid development of optoelectronic technology has seen researchers employing techniques such as stable multi-color multi-ring lights [10], stripe lights [11], and point lasers [12] to project structured light onto hole walls and using cameras to capture images of structured light for deep hole inner wall measurement, thus advancing deep hole measurement technology.…”

Section: Introductionmentioning

confidence: 99%

Improving Measurement Accuracy of Deep Hole Measurement Instruments through Perspective Transformation

Zhao,

Du,

2024

Sensors

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Deep hole measurement is a crucial step in both deep hole machining and deep hole maintenance. Single-camera vision presents promising prospects in deep hole measurement due to its simple structure and low-cost advantages. However, the measurement error caused by the heating of the imaging sensor makes it difficult to achieve the ideal measurement accuracy. To compensate for measurement errors induced by imaging sensor heating, this study proposes an error compensation method for laser and vision-based deep hole measurement instruments. This method predicts the pixel displacement of the entire field of view using the pixel displacement of fixed targets within the camera’s field of view and compensates for measurement errors through a perspective transformation. Theoretical analysis indicates that the perspective projection matrix changes due to the heating of the imaging sensor, which causes the thermally induced measurement error of the camera. By analyzing the displacement of the fixed target point, it is possible to monitor changes in the perspective projection matrix and thus compensate for camera measurement errors. In compensation experiments, using target displacement effectively predicts pixel drift in the pixel coordinate system. After compensation, the pixel error was suppressed from 1.99 pixels to 0.393 pixels. Repetitive measurement tests of the deep hole measurement instrument validate the practicality and reliability of compensating for thermal-induced errors using perspective transformation.

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An Electronically Stabilized Multi-Color Multi-Ring Structured Light Sensor for Gas Pipelines Internal Surface Inspection

Cited by 14 publications

References 23 publications

Design of hexapod robot equipped with omnidirectional vision sensor for defect inspection of pipeline’s inner surface

Design of hexapod robot equipped with omnidirectional vision sensor for defect inspection of pipeline’s inner surface

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Improving Measurement Accuracy of Deep Hole Measurement Instruments through Perspective Transformation

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