TH-E-L100J-02: A High Precision Geometry Calibration Method for Digital Tomosynthesis Systems

2007 ◽  
Vol 34 (6Part24) ◽  
pp. 2645-2645
Author(s):  
X Li ◽  
B Liu
Keyword(s):  
High Precision ◽  
Calibration Method ◽  
Digital Tomosynthesis ◽  
Geometry Calibration

Optical geometry calibration method for free-form digital tomosynthesis

2016 ◽  
Author(s):  
Pavel Chtcheprov ◽  
Allison Hartman ◽  
Jing Shan ◽  
Yueh Z. Lee ◽  
Otto Zhou ◽  
...  
Keyword(s):  
Calibration Method ◽  
Free Form ◽  
Digital Tomosynthesis ◽  
Optical Geometry ◽  
Geometry Calibration

Industrial part localization and grasping using a robotic arm guided by 2D monocular vision

2018 ◽  
Vol 45 (6) ◽  
pp. 794-804 ◽  
Author(s):  
Zhaohui Zheng ◽  
Yong Ma ◽  
Hong Zheng ◽  
Yu Gu ◽  
Mingyu Lin
Keyword(s):  
Camera Calibration ◽  
High Precision ◽  
Calibration Method ◽  
Monocular Vision ◽  
Robotic Arm ◽  
Robot Arm ◽  
Content Type ◽  
Calibration Algorithm ◽  
Target Locating ◽  
Practical Implications

Purpose The welding areas of the workpiece must be consistent with high precision to ensure the welding success during the welding of automobile parts. The purpose of this paper is to design an automatic high-precision locating and grasping system for robotic arm guided by 2D monocular vision to meet the requirements of automatic operation and high-precision welding. Design/methodology/approach A nonlinear multi-parallel surface calibration method based on adaptive k-segment master curve algorithm is proposed, which improves the efficiency of the traditional single camera calibration algorithm and accuracy of calibration. At the same time, the multi-dimension feature of target based on k-mean clustering constraint is proposed to improve the robustness and precision of registration. Findings A method of automatic locating and grasping based on 2D monocular vision is provided for robot arm, which includes camera calibration method and target locating method. Practical implications The system has been integrated into the welding robot of an automobile company in China. Originality/value A method of automatic locating and grasping based on 2D monocular vision is proposed, which makes the robot arm have automatic grasping function, and improves the efficiency and precision of automatic grasp of robot arm.

scholarly journals A Nonlinear Calibration Method Based on Sinusoidal Excitation and DFT Transformation for High-Precision Power Analyzers

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Wenjian Zhou ◽  
Sheng Yang ◽  
Li Wang ◽  
Hanmin Sheng ◽  
Yang Deng
Keyword(s):  
High Precision ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Calibration Method ◽  
Calibration Error ◽  
Initial Moment ◽  
Calibration Process ◽  
Calibration Methods ◽  
Nonlinear Calibration ◽  
Sinusoidal Excitation

For most high-precision power analyzers, the measurement accuracy may be affected due to the nonlinear relationship between the input and output signal. Therefore, calibration before measurement is important to ensure accuracy. However, the traditional calibration methods usually have complicated structures, cumbersome calibration process, and difficult selection of calibration points, which is not suitable for situations with many measurement points. To solve these issues, a nonlinear calibration method based on sinusoidal excitation and DFT transformation is proposed in this paper. By obtaining the effective value data of the current sinusoidal excitation from the calibration source, the accurate calibration process can be done, and the calibration efficiency can be improved effectively. Firstly, through Fourier transform, the phase value at the initial moment of the fundamental frequency is calculated. Then, the mapping relationship between the sampling value and the theoretical calculation value is established according to the obtained theoretical discrete expression, and a cubic spline interpolation method is used to further reduce the calibration error. Simulations and experiments show that the calibration method presented in this paper achieves high calibration accuracy, and the results are compensation value after calibration with a deviation of ± 3 × 10 − 4 .

scholarly journals Flexible method for accurate calibration of large-scale vision metrology system based on virtual 3-D targets and laser tracker

2019 ◽  
Vol 16 (6) ◽  
pp. 172988141989351
Author(s):  
Xi Zhang ◽  
Yuanzhi Xu ◽  
Haichao Li ◽  
Lijing Zhu ◽  
Xin Wang ◽  
...  
Keyword(s):  
High Precision ◽  
Stereo Vision ◽  
Large Scale ◽  
Vision System ◽  
Calibration Method ◽  
Field Of View ◽  
Large Field ◽  
Laser Tracker ◽  
Calibration Target ◽  
Pose Tracking

For the purpose of obtaining high-precision in stereo vision calibration, a large-size precise calibration target, which can cover more than half of the field of view is vital. However, large-scale calibration targets are very difficult to fabricate. Based on the idea of error tracing, a high-precision calibration method for vision system with large field of view by constructing a virtual 3-D calibration target with a laser tracker was proposed in this article. A virtual 3-D calibration target that covers the whole measurement space can be established flexibly and the measurement precision of the vision system can be traceable to the laser tracker. First, virtual 3-D targets by calculating rigid body transformation with unit quaternion method were constructed. Then, the high-order distortion camera model was taken into consideration. Besides, the calibration parameters were solved with Levenberg–Marquardt optimization algorithm. In the experiment, a binocular stereo vision system with the field of view of 4 × 3 × 2 m3 was built for verifying the validity and precision of the proposed calibration method. It is measured that the accuracy with the proposed method can be greatly improved comparing with traditional plane calibration method. The method can be widely used in industrial applications, such as in the field of calibrating large-scale vision-based coordinate metrology, and six-degrees of freedom pose tracking system for dimensional measurement of workpiece, as well as robotics geometrical accuracy detection and compensation.

Self-Calibration of XY-Stage with Parallel Mechanism

2014 ◽  
Vol 590 ◽  
pp. 126-129
Author(s):  
Ryoshu Furutani ◽  
Satoshi Yokouchi ◽  
Miyu Ozaki
Keyword(s):  
High Precision ◽  
Parallel Mechanism ◽  
Least Squares Method ◽  
Calibration Method ◽  
Measuring Instruments ◽  
Precision Manufacturing ◽  
Kinematic Parameters ◽  
Self Calibration ◽  
Simulation And Experiment ◽  
Experimental Process

It is important to calibrate the straightness and the squareness of the XY-stage for precision manufacturing and measurement. Normally it is calibrated using much higher precise and accurate measuring instruments and/or artifacts. The high precision and accurate instruments and artifacts are expensive. So, in this paper, Self-calibration method is applied to XY-stage. This method does not require any much high precision and accurate instruments and artifacts. The normal XY-stage moves to the location at the unique coordinates. In this case, it is difficult to apply self-calibration method. Therefore, XY-stage is expanded to XYθ-stage with parallel mechanism. As this stage moves to the location at a lot of coordinates, self-calibration method is applied. This method is confirmed in simulation and experiment. In simulation, the extension lengths of mechanism are estimated from known kinematic parameters and the target coordinates. After that, estimated kinematic parameters are calculated by least-squares method from the extension lengths and the target coordinates. Finally, the positioning coordinates are calculated from the estimated kinematic parameters and the extension lengths. It is proved that the calibration method is effective by comparing the target coordinates and the positioning coordinates. In experiment, the experimental process is similar to the simulation without the estimation of extension lengths. The results of simulation and experiment are shown in this paper.

Research on Calibration Method of Linear Structured Light Vision Measurement System

2014 ◽  
Vol 644-650 ◽  
pp. 1234-1239
Author(s):  
Tao He ◽  
Yu Lang Xie ◽  
Cai Sheng Zhu ◽  
Jiu Yin Chen
Keyword(s):  
High Precision ◽  
Measurement System ◽  
Structured Light ◽  
Target Position ◽  
Calibration Method ◽  
Measurement Model ◽  
Sensor Calibration ◽  
Vision Measurement ◽  
Set Up ◽  
Structured Light Vision

This template explains and demonstrates how to design a measurement system based on the size of the linear structured light vision, the system could works at realized the high precision and fast measurement of the size of mechanical parts, and accurate calibration of the system. First of all, this paper set up the experimental platform based on linear structured light vision measurement. Secondly, this paper established a system of measurement model, and puts forward a new method of calibration of structured light sensor and set up the mathematical model of sensor calibration. This calibration method only need to use some gage blocks of high precision as the target, the target position need not have a strict requirements, and the solving process will be more convenient, much easier to field use and maintenance. Finally, measuring accuracy on the system by gage blocks with high precision is verified, the experiment shows that measurement accuracy within 0.050 mmin the depth of 0-80 - mm range. This system can satisfy the demands of precision testing of most industrial parts .with its simple calibration process and high precision, it is suitable for the structured light vision calibration.

Geometry calibration method for a cone-beam CT system

2017 ◽  
Vol 44 (5) ◽  
pp. 1692-1706 ◽  
Author(s):  
Hongkai Yang ◽  
Kejun Kang ◽  
Yuxiang Xing
Keyword(s):  
Cone Beam Ct ◽  
Calibration Method ◽  
Cone Beam ◽  
Ct System ◽  
Geometry Calibration
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