Weld Line Detection and Tracking via Spatial-Temporal Cascaded Hidden Markov Models and Cross Structured Light

Zhang, Liguo; Ye, Qixiang; Yang, Wei; Jiao, J. B.

doi:10.1109/tim.2013.2283139

Cited by 67 publications

(21 citation statements)

References 28 publications

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“…In (4), the plane 1 c is expressed in the camera coordinate system. Note that there are three planes in Fig.…”

Section: Computation Ofmentioning

confidence: 99%

“…Note that the unknown parameters in (9) are 1 n and 1 d . Equation (9) can be written in the following form: ( )…”

Section: Computation Ofmentioning

confidence: 99%

“…Thus we can compute the plane 1 l equation in the camera coordinate system. Using the exactly same method, we can compute the plane 2 l equation in the camera coordinate system as well.…”

Section: Computation Ofmentioning

confidence: 99%

“…, a a x y given on the laser plane 1 l , the corresponding 3D point in the camera coordinate frame is computed as…”

Section: Computation Ofmentioning

confidence: 99%

“…It is applied for welding detection [1], 3D depth map construction [2], polyhedral surfaces location and orientation [3], and 3D object identification [4]. The laser structured light system consists of a laser (line or cross type) together with a camera.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Golf Green Slope Estimation Using a Cross Laser Structured Light System and an Accelerometer

Pham¹,

Dang²,

Suh³

2016

Journal of Electrical Engineering and Technology

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-In this paper, we propose a method combining an accelerometer with a cross structured light system to estimate the golf green slope. The cross-line laser provides two laser planes whose functions are computed with respect to the camera coordinate frame using a least square optimization. By capturing the projections of the cross-line laser on the golf slope in a static pose using a camera, two 3D curves' functions are approximated as high order polynomials corresponding to the camera coordinate frame. Curves' functions are then expressed in the world coordinate frame utilizing a rotation matrix that is estimated based on the accelerometer's output. The curves provide some important information of the green such as the height and the slope's angle. The curves estimation accuracy is verified via some experiments which use OptiTrack camera system as a ground-truth reference.

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“…In (4), the plane 1 c is expressed in the camera coordinate system. Note that there are three planes in Fig.…”

Section: Computation Ofmentioning

confidence: 99%

“…Note that the unknown parameters in (9) are 1 n and 1 d . Equation (9) can be written in the following form: ( )…”

Section: Computation Ofmentioning

confidence: 99%

“…Thus we can compute the plane 1 l equation in the camera coordinate system. Using the exactly same method, we can compute the plane 2 l equation in the camera coordinate system as well.…”

Section: Computation Ofmentioning

confidence: 99%

“…, a a x y given on the laser plane 1 l , the corresponding 3D point in the camera coordinate frame is computed as…”

Section: Computation Ofmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Golf Green Slope Estimation Using a Cross Laser Structured Light System and an Accelerometer

Pham¹,

Dang²,

Suh³

2016

Journal of Electrical Engineering and Technology

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Fractional‐order PID servo control based on decoupled visual model

Liu

Bian

Rahman

et al. 2018

Adaptive Control & Signal

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A decoupled visual model and a fractional PID controller are designed aiming at the problem of the view distortion in the fillet weld welding process. Firstly, the intersection point coordinates of two laser stripes are selected as the image characteristics, and the decoupled visual model is designed to the tracking control of the fillet weld seam so that the control value in two directions is decoupled, reducing the difficulty of control. In addition to this, the image may produce distortion in the dynamic tracking process, causing nonlinearity and coupling in two directions. To solve this problem, the fractional-order PID controller is designed so that the adjustment range and the control ability are improved better than the traditional PID controller. Some experiments verify that the desired performance can be achieved by using the proposed methods.

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Weld line recognition and path planning with spherical tank inspection robots

Jin

Wang

et al. 2021

Journal of Field Robotics

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Periodic inspections are required for the safe operation of large pressure vessels such as spherical tanks. Inspection robots have been applied in large pressure vessels due to their low cost and high efficiency. This paper presents a robotic system for the inspection of spherical tanks, which can identify and track weld lines on the shortest running route. Two-dimensional (2D) weld maps were prepared for robot path planning on the basis of the actual distribution of weld lines. In 2D weld maps, indispensable repetitive lines were added to form an Eulerian circuit that traversed all weld lines. In addition, an improved Fleury algorithm was proposed to solve Eulerian circuit and plan an optimal running route for robot inspection. To accurately identify weld lines, deep learning networks were constructed and trained with weld line data sets, which were captured by the camera mounted in the front of the robot.The laboratory experiments indicated that the inspection robot could identify weld lines within 0.2-0.25 s and track weld lines with a maximum offset of ±20 mm. The experiment results demonstrated that the robot could plan the shortest path to traverse all weld lines on the experimental platform. In the field tests, the virtual simulation of weld path planning on spherical tanks was explored in detail. The field tests of a spherical tank (3000 m 3 ) verified that the robotic system could improve the efficiency and stability of inspection operations and replace manual inspection with automated weld line recognition and weld path planning.

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Weld Line Detection and Tracking via Spatial-Temporal Cascaded Hidden Markov Models and Cross Structured Light

Cited by 67 publications

References 28 publications

Golf Green Slope Estimation Using a Cross Laser Structured Light System and an Accelerometer

Golf Green Slope Estimation Using a Cross Laser Structured Light System and an Accelerometer

Fractional‐order PID servo control based on decoupled visual model

Weld line recognition and path planning with spherical tank inspection robots

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