Automatic Calibration Method for Mounting Position of Protein Crystal Mounting Robot Based on Visual Positioning

2020 ◽  
Author(s):  
Jiangping Qin ◽  
Zhaolong Li ◽  
Bo Sun ◽  
Feng Yu ◽  
Yi Liu ◽  
...  
Keyword(s):  
Calibration Method ◽  
Image Features ◽  
Protein Crystal ◽  
External Parameter ◽  
Automatic Calibration ◽  
Relationship Matrix ◽  
Laser Sensor ◽  
Circle Fitting ◽  
Visual Positioning ◽  
Fitting Algorithm

Abstract With the popularization of automounting robots in protein crystal diffraction experiment beamline stations, the coordinate calibration of the robot sample mounting position has become an inevitable task in the daily maintenance of the beamline station. In this method, the image features of the laser sensor spot and goniometer are extracted by color extraction and edge detection, respectively, and the noise is eliminated by median filtering. Then, after locating the pixel coordinates of the center of the circle through the Hough circle detection and the minimum closed circle fitting algorithm, the coordinates in the base coordinate system are obtained using the camera internal and external parameter matrices and the hand-eye relationship matrix. Finally, according to the deviation of the laser spot and the visual positioning coordinate of the goniometer, the position of the robot is compensated to improve the positioning accuracy, and the automatic calibration of the sample point is realized.

A robot hand-eye calibration method of line laser sensor based on 3D reconstruction

2021 ◽  
Vol 71 ◽  
pp. 102136
Author(s):  
Mingyang Li ◽  
Zhijiang Du ◽  
Xiaoxing Ma ◽  
Wei Dong ◽  
Yongzhuo Gao
Keyword(s):  
3D Reconstruction ◽  
Calibration Method ◽  
Laser Sensor ◽  
Robot Hand

scholarly journals Constrained Multiple Planar Reconstruction for Automatic Camera Calibration of Intelligent Vehicles

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4643
Author(s):  
Sang Jun Lee ◽  
Jeawoo Lee ◽  
Wonju Lee ◽  
Cheolhun Jang
Keyword(s):  
Camera Calibration ◽  
Calibration Method ◽  
Image Features ◽  
Intelligent Vehicles ◽  
Point Problem ◽  
Reconstruction Method ◽  
Calibration Methods ◽  
The World ◽  
Extrinsic Parameters ◽  
Automatic Camera Calibration

In intelligent vehicles, extrinsic camera calibration is preferable to be conducted on a regular basis to deal with unpredictable mechanical changes or variations on weight load distribution. Specifically, high-precision extrinsic parameters between the camera coordinate and the world coordinate are essential to implement high-level functions in intelligent vehicles such as distance estimation and lane departure warning. However, conventional calibration methods, which solve a Perspective-n-Point problem, require laborious work to measure the positions of 3D points in the world coordinate. To reduce this inconvenience, this paper proposes an automatic camera calibration method based on 3D reconstruction. The main contribution of this paper is a novel reconstruction method to recover 3D points on planes perpendicular to the ground. The proposed method jointly optimizes reprojection errors of image features projected from multiple planar surfaces, and finally, it significantly reduces errors in camera extrinsic parameters. Experiments were conducted in synthetic simulation and real calibration environments to demonstrate the effectiveness of the proposed method.

scholarly journals Consistent Calibration of VIRR Reflective Solar Channels Onboard FY-3A, FY-3B, and FY-3C Using a Multisite Calibration Method

2018 ◽  
Vol 10 (9) ◽  
pp. 1336 ◽  
Author(s):  
Ling Wang ◽  
Xiuqing Hu ◽  
Lin Chen ◽  
Lingli He
Keyword(s):  
Radiative Transfer ◽  
Calibration Method ◽  
Daily Basis ◽  
Current Approach ◽  
Automatic Calibration ◽  
Vicarious Calibration ◽  
Radiative Transfer Modeling ◽  
Reflectance Data ◽  
Calibration Coefficients

The FengYun-3 (FY-3) Visible Infrared Radiometer (VIRR), along with its predecessor, the Multispectral Visible Infrared Scanning Radiometer (MVISR), onboard the FY-1C and FY-1D, has collected continuous daily global observations for 18 years. Achieving accurate and consistent calibration for VIRR reflective solar bands (RSBs) has been challenging, as there is no onboard calibrator and the frequency of in situ vicarious calibration is limited. In this study, a new set of reflectance calibration coefficients were derived for RSBs of the FY-3A, FY-3B, and FY-3C VIRRs using a multisite (MST) calibration method. This method is an extension of a previous MST calibration method, which relies on radiative transfer modeling over the multiple stable earth sites, and no synchronous in situ measurements are needed; hence, it can be used to update the VIRR calibration on a daily basis. The on-orbit radiometric changes of the VIRR onboard the FY-3 series were assessed based on analyses of new sets of calibration slopes. Then, all recalibrated VIRR reflectance data over Libya 4, the most frequently used stable Earth site, were compared with those provided from the Level 1B (L1B) product. Additional validation was performed by comparing the recalibrated VIRR data with those derived from radiative transfer simulations using measurements from automatic calibration instruments in Dunhuang. The results indicate that the radiometric response changes of the VIRRs onboard FY-3A and FY-3B were larger than those of FY-3C VIRR and were wavelength dependent. The current approach can provide consistent VIRR reflectances across different FY-3 satellite platforms. After recalibration, differences in top-of-atmosphere (TOA) reflectance data across different VIRRs during the whole lifetime decreased from 5–10% to less than 3%. The comparison with the automatic calibration method indicates that MST calibration shows good accuracy and lower temporal oscillations.

The Design of HTG Automatic Calibration System Based on Fuzzy Theory

2012 ◽  
Vol 468-471 ◽  
pp. 1490-1494
Author(s):  
Qi Ren ◽  
Tian Fei Ren
Keyword(s):  
Control Theory ◽  
System Design ◽  
Fuzzy Theory ◽  
Calibration Method ◽  
Automatic Calibration ◽  
Matlab Simulation ◽  
Calibration System ◽  
Oil Tank ◽  
Fuel Level

ABSTRACT：It introduces a kind of an Automatic Calibration System, especially for long-term drift of oil tank gauging system. long-term drift serious influence on measuring the accuracy and reliability of the system. With theory of Hydrostatic Tank Gauging[1]（HTG），as soon as the long-term drift occurring, the detection drift of oil pressure valueΔp will drift，and soon other the parameters of tank Gauging will be occurred. Because the value of Δp is difficult to directly determine, This paper puts forward a kind of automatic calibration method to obtain Δp according to the fuel level drift Δh) indirectly,By means of the HTG double level switches and fuzzy control theory. At last, by MATLAB simulation verify the correctness of the system design.

scholarly journals A Novel Calibration Algorithm for Cable-Driven Parallel Robots with Application to Rehabilitation

2019 ◽  
Vol 9 (11) ◽  
pp. 2182 ◽  
Author(s):  
Han Yuan ◽  
Xianghui You ◽  
Yongqing Zhang ◽  
Wenjing Zhang ◽  
Wenfu Xu
Keyword(s):  
Calibration Method ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Human Robot Interaction ◽  
Automatic Calibration ◽  
Unknown Parameters ◽  
Robot Interaction ◽  
Geometric Calibration ◽  
Rehabilitation Robots ◽  
Calibration Algorithm

Cable-driven parallel robots are suitable candidates for rehabilitation due to their intrinsic flexibility and adaptability, especially considering the safety of human–robot interaction. However, there are still some challenges to apply cable-driven parallel robots to rehabilitation, one of which is the geometric calibration. This paper proposes a new automatic calibration method that is applicable for cable-driven parallel rehabilitation robots. The key point of this method is to establish the mapping between the unknown parameters to be calibrated and the parameters that could be measured by the inner sensors and then use least squares algorithm to find the solutions. Specifically, the unknown parameters herein are the coordinates of the attachment points, and the measured parameters are the lengths of the redundant cables. Simulations are performed on a 3-DOF parallel robot driven by four cables for validation. Results show that the proposed calibration method could precisely find the real coordinate values of the attachment points, with errors less than 10 − 12 mm. Trajectory simulations also indicate that the positioning accuracy of the cable-driven parallel robot (CDPR) could be greatly improved after calibration using the proposed method.

Automatic calibration method for plenoptic camera

2016 ◽  
Vol 55 (4) ◽  
pp. 043111 ◽  
Author(s):  
Yinsen Luan ◽  
Xing He ◽  
Bing Xu ◽  
Ping Yang ◽  
Guomao Tang
Keyword(s):  
Calibration Method ◽  
Automatic Calibration ◽  
Plenoptic Camera

scholarly journals A High Precision Laser-Based Autofocus Method Using Biased Image Plane for Microscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Chao-Chen Gu ◽  
Hao Cheng ◽  
Kai-Jie Wu ◽  
Liang-Jun Zhang ◽  
Xin-Ping Guan
Keyword(s):  
Laser Beam ◽  
High Precision ◽  
Low Cost ◽  
Image Plane ◽  
Circle Fitting ◽  
Essential Factor ◽  
Assembly Accuracy ◽  
Fitting Algorithm ◽  
Experiment Device ◽  
Study Designs

This study designs and accomplishes a high precision and robust laser-based autofocusing system, in which a biased image plane is applied. In accordance to the designed optics, a cluster-based circle fitting algorithm is proposed to calculate the radius of the detecting spot from the reflected laser beam as an essential factor to obtain the defocus value. The experiment conduct on the experiment device achieved novel performance of high precision and robustness. Furthermore, the low demand of assembly accuracy makes the proposed method a low-cost and realizable solution for autofocusing technique.

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