scholarly journals Field Geometric Calibration Method for Line Structured Light Sensor Using Single Circular Target

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Tianfei Chen ◽  
Lijun Sun ◽  
Qiuwen Zhang ◽  
Xiang Wu ◽  
Defeng Wu
Keyword(s):  
Structured Light ◽  
Linear Equations ◽  
Calibration Method ◽  
Experimental Result ◽  
Normal Vector ◽  
Geometric Calibration ◽  
Light Plane ◽  
Light Sensor ◽  
Fitting Method ◽  
Circular Target

To achieve fast calibration of line structured light sensor, a geometric calibration approach based on single circular calibration target is proposed. The proposed method uses the circular points to establish linear equations, and according to the angle constraint, the camera intrinsic parameters can be calculated through optimization. Then, the light plane calibration is accomplished in two steps. Firstly, when the vanishing lines of target plane at various postures are obtained, the intersections between vanishing lines and laser stripe can be computed, and the normal vector of light plane can be calibrated via line fitting method using intersection points. After that, the distance from the origin of camera coordinate system to the light plane can be derived based on the model of perspective-three-point. The actual experimental result shows that this calibration method has high accuracy, its average measuring accuracy is 0.0451 mm, and relative error is 0.2314%. In addition, the entire calibration process has no complex operations. It is simple, convenient, and suitable for calibration on sites.

scholarly journals Calibration Method for Line-Structured Light Three-Dimensional Measurements Based on a Single Circular Target

2022 ◽  
Vol 12 (2) ◽  
pp. 588
Author(s):  
Jun Wang ◽  
Xuexing Li
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Calibration Method ◽  
Optical Center ◽  
3D Measurements ◽  
Light Plane ◽  
Laser Projector ◽  
Dimensional Measurements ◽  
Intersection Points ◽  
Circular Target

Single circular targets are widely used as calibration objects during line-structured light three-dimensional (3D) measurements because they are versatile and easy to manufacture. This paper proposes a new calibration method for line-structured light 3D measurements based on a single circular target. First, the target is placed in several positions and illuminated by a light beam emitted from a laser projector. A camera captures the resulting images and extracts an elliptic fitting profile of the target and the laser stripe. Second, an elliptical cone equation defined by the elliptic fitting profile and optical center of the camera is established based on the projective geometry. By combining the obtained elliptical cone and the known diameter of the circular target, two possible positions and orientations of the circular target are determined and two groups of 3D intersection points between the light plane and the circular target are identified. Finally, the correct group of 3D intersection points is filtered and the light plane is progressively fitted. The accuracy and effectiveness of the proposed method are verified both theoretically and experimentally. The obtained results indicate that a calibration accuracy of 0.05 mm can be achieved for an 80 mm × 80 mm planar target.

Light Plane Calibration Method Using Line Transformation for Line Structured Light Measurement

2021 ◽  
Vol 58 (2) ◽  
pp. 0212001
Author(s):  
翟鹏 Zhai Peng ◽  
崔海华 Cui Haihua ◽  
胡广露 Hu Guanglu ◽  
张益华 Zhang Yihua ◽  
靳宇婷 Jin Yuting ◽  
...  
Keyword(s):  
Structured Light ◽  
Calibration Method ◽  
Light Plane ◽  
Light Measurement

New Calibration Method for Line Structured Light Sensor Based on Planar Target

2015 ◽  
Vol 35 (1) ◽  
pp. 0112004 ◽  
Author(s):  
陈天飞 Chen Tianfei ◽  
赵吉宾 Zhao Jibin ◽  
吴翔 Wu Xiang
Keyword(s):  
Structured Light ◽  
Calibration Method ◽  
Light Sensor ◽  
Planar Target

Welding robotic hand-eye calibration method based on structured light plane

2019 ◽  
Author(s):  
Fangkai Xu ◽  
Shengli Fan ◽  
Qingqing Yang ◽  
Chang Zhang ◽  
Yigang Wang
Keyword(s):  
Structured Light ◽  
Calibration Method ◽  
Robotic Hand ◽  
Light Plane

Computer Hard Disk Planeness Vision Measurement System Calibration Based on Light Plane Constraint

2013 ◽  
Vol 475-476 ◽  
pp. 63-67
Author(s):  
Rui Yin Tang ◽  
Zhou Mo Zeng ◽  
Peng Fei Li
Keyword(s):  
Nonlinear Model ◽  
Constraint Equation ◽  
Hard Disk ◽  
Calibration Method ◽  
Calibration Target ◽  
System Calibration ◽  
Vision Measurement ◽  
Light Plane ◽  
Fitting Method ◽  
Extrinsic Parameters

This paper proposed a calibration method of sheet-of-light vision measurement sensor based on light plane constraint. Through capturing 12 images of different direction from homemade circular calibration target, the center of the circle and the light stripe is extracted based on Halcon platform of Germany. The experimental results obtained the intrinsic parameters, extrinsic parameters and radial distortion coefficient of the nonlinear model. At the same time the light plane constraint equation is got based on PCA plane fitting method. The results show that the calibration method is simple and reliable, and the method does not need any auxiliary adjustment. The work laid the better foundation for hard disk planeness vision measurement.

scholarly journals A Model of Diameter Measurement Based on the Machine Vision

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 187
Author(s):  
Qingchang Tan ◽  
Ying Kou ◽  
Jianwei Miao ◽  
Siyuan Liu ◽  
Bosen Chai
Keyword(s):  
Rotational Symmetry ◽  
Structured Light ◽  
Measurement Model ◽  
Optical Center ◽  
Machining Accuracy ◽  
Normal Vector ◽  
Shaft Diameter ◽  
Light Plane ◽  
Elliptic Cone

If the shaft diameter can be measured in-situ during the finishing process, the closed-loop control of the shaft diameter processing process can be realized and the machining accuracy can be improved. Present work studies the measurement of shaft diameter with the structured light system composed of a laser linear light source and a camera. The shaft is a kind of part with rotationally symmetric structure. When the linear structured light irradiates the surface of the shaft, a light stripe will be formed, and the light stripe is a part of the ellipse. Therefore, the in-situ measurement of the shaft diameter can be realized by the light stripe and the rotational symmetry of the shaft. The measurement model of shaft diameter is established by the ellipse formed by the intersection of the light plane and the measured shaft surface. Firstly, in the camera coordinate system, normal vector of the light plane and the coordinates of the ellipse center are obtained by the calibration; then, the equation of oblique elliptic cone is established by taking the ellipse as the bottom and the optical center of the camera as the top. Next, the measurement model of shaft diameter is obtained by the established oblique elliptic cone equation and theoretical image plane equation. Finally, the accuracy of the measurement model of shaft diameter is tested by the checkerboard calibration plate and a lathe. The test results show that the measurement model of shaft diameter is correct, and when the shaft diameter is 36.162mm, the speed is 1250r/min, the maximum average measurement error is 0.019mm. The measurement accuracy meets the engineering requirement.

Calibration of light plane in line structured light sensor based on active vision

2012 ◽  
Vol 20 (2) ◽  
pp. 256-263 ◽  
Author(s):  
陈天飞 CHEN Tian-fei ◽  
马孜 MA Zi ◽  
吴翔 WU Xiang
Keyword(s):  
Structured Light ◽  
Active Vision ◽  
Light Plane ◽  
Light Sensor
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