Camera Calibration Method of Medical Robot Positioning System Based on Binocular Vision

2013 ◽  
Vol 12 (16) ◽  
pp. 3524-3529
Author(s):  
Dong Feng ◽  
Sun Li-Ning ◽  
Ru Chang-Hai
Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 45
Author(s):  
Roberto Pagani ◽  
Cristina Nuzzi ◽  
Marco Ghidelli ◽  
Alberto Borboni ◽  
Matteo Lancini ◽  
...  

Since cobots are designed to be flexible, they are frequently repositioned to change the production line according to the needs; hence, their working area (user frame) needs to be often calibrated. Therefore, it is important to adopt a fast and intuitive user frame calibration method that allows even non-expert users to perform the procedure effectively, reducing the possible mistakes that may arise in such contexts. The aim of this work was to quantitatively assess the performance of different user frame calibration procedures in terms of accuracy, complexity, and calibration time, to allow a reliable choice of which calibration method to adopt and the number of calibration points to use, given the requirements of the specific application. This has been done by first analyzing the performances of a Rethink Robotics Sawyer robot built-in user frame calibration method (Robot Positioning System, RPS) based on the analysis of a fiducial marker distortion obtained from the image acquired by the wrist camera. This resulted in a quantitative analysis of the limitations of this approach that only computes local calibration planes, highlighting the reduction of performances observed. Hence, the analysis focused on the comparison between two traditional calibration methods involving rigid markers to determine the best number of calibration points to adopt to achieve good repeatability performances. The analysis shows that, among the three methods, the RPS one resulted in very poor repeatability performances (1.42 mm), while the three and five points calibration methods achieve lower values (0.33 mm and 0.12 mm, respectively) which are closer to the reference repeatability (0.08 mm). Moreover, comparing the overall calibration times achieved by the three methods, it is shown that, incrementing the number of calibration points to more than five, it is not suggested since it could lead to a plateau in the performances, while increasing the overall calibration time.


Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2170
Author(s):  
Wentai Lei ◽  
Mengdi Xu ◽  
Feifei Hou ◽  
Wensi Jiang ◽  
Chiyu Wang ◽  
...  

Cameras are widely used in many scenes such as robot positioning and unmanned driving, in which the camera calibration is a major task in this field. The interactive camera calibration method based on a plane board is becoming popular due to its stability and handleability. However, most methods choose suggestions subjectively from a fixed pose dataset, which is error-prone and limited for different camera models. In addition, these methods do not provide clear guidelines on how to place the board in the specified pose. This paper proposes a new interactive calibration method, named ‘Calibration Venus’, including two main parts: pose search and pose decomposition. First, a pose search algorithm based on simulated annealing (SA) algorithm is proposed to select the optimal pose in the entire pose space. Second, an intuitive and easy-to-use user guidance method is designed to decompose the optimal pose into four sub-poses: translation, each rotation along X-, Y-, Z-axes. Thereby the users could follow the guide step by step to accurately complete the placement of the calibration board. Experimental results evaluated on simulated and real datasets show that the proposed method can reduce the difficulty of calibration, and improve the accuracy of calibration, as well as provide better guidance.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanjun Zhang ◽  
Jianxin zhao ◽  
Heyong Han

In this paper, the principle of camera imaging is studied, and the transformation model of camera calibration is analyzed. Based on Zhang Zhengyou’s camera calibration method, an automatic calibration method for monocular and binocular cameras is developed on a multichannel vision platform. The automatic calibration of camera parameters using human-machine interface of the host computer is realized. Based on the principle of binocular vision, a feasible three-dimensional positioning method for binocular target points is proposed and evaluated to provide binocular three-dimensional positioning of target in simple environment. Based on the designed multichannel vision platform, image acquisition, preprocessing, image display, monocular and binocular automatic calibration, and binocular three-dimensional positioning experiments are conducted. Moreover, the positioning error is analyzed, and the effectiveness of the binocular vision module is verified to justify the robustness of our approach.


IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 44354-44362
Author(s):  
Mingwei Shao ◽  
Pan Wang ◽  
Yanjun Wang

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuxiang Wang ◽  
Zhangwei Chen ◽  
Hongfei Zu ◽  
Xiang Zhang ◽  
Chentao Mao ◽  
...  

The positioning accuracy of a robot is of great significance in advanced robotic manufacturing systems. This paper proposes a novel calibration method for improving robot positioning accuracy. First of all, geometric parameters are identified on the basis of the product of exponentials (POE) formula. The errors of the reduction ratio and the coupling ratio are identified at the same time. Then, joint stiffness identification is carried out by adding a load to the end-effector. Finally, residual errors caused by nongeometric parameters are compensated by a multilayer perceptron neural network (MLPNN) based on beetle swarm optimization algorithm. The calibration is implemented on a SIASUN SR210D robot manipulator. Results show that the proposed method possesses better performance in terms of faster convergence and higher precision.


2021 ◽  
Vol 1748 ◽  
pp. 042011
Author(s):  
Xing Zhang ◽  
Qiaoming Gao ◽  
Dong Pan ◽  
Peng Cheng Cao ◽  
Dong Hui Huang

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