A Global Calibration Method of Multi-Vision Sensors in the Measurement of Engine Cylinder Joint Surface Holes

2011 ◽  
Vol 467-469 ◽  
pp. 1182-1188 ◽  
Author(s):  
Yong Qiang Shi ◽  
Chang Ku Sun ◽  
Bao Guang Wang ◽  
Peng Wang ◽  
Hong Xu Duan
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Calibration Method ◽  
Joint Surface ◽  
Calibration Target ◽  
Whole Process ◽  
Global Calibration ◽  
Vision Sensors ◽  
Engine Cylinder

The measurement of engine cylinder joint surface holes is directly related to the control of product quality and the follow-up assembly. CMM is widely used in this field but can not meet the inspection requirements of automation, rapidity and Online testing. In this paper, a new measurement scheme based on the combination of multi-vision sensors is proposed. The global calibration method is focused on and a new dedicated calibration target is designed. The whole process of the system global calibration can be accomplished quickly through single imaging. The experiment results show that the method is feasible and with high precision. The method mentioned above can satisfy the engine production line requirements of intelligence, rapidity, high precision and low cost.

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.

scholarly journals Flexible and Accurate Calibration Method for Non-Overlapping Vision Sensors Based on Distance and Reprojection Constraints

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4623 ◽  
Author(s):  
Tao Jiang ◽  
Xu Chen ◽  
Qiang Chen ◽  
Zhe Jiang
Keyword(s):  
Calibration Method ◽  
Bundle Adjustment ◽  
Experimental Results ◽  
Laser Tracker ◽  
Distance Error ◽  
Global Calibration ◽  
Vision Sensors ◽  
Extrinsic Parameters ◽  
Calibration Pattern

This paper addresses the problem of flexible and accurate global calibration for multiple non-overlapping vision sensors in a confined workspace. Instead of using an auxiliary calibration pattern, the proposed method uses one laser tracker and only its accessory target sphere to obtain all the 3D calibration points and then accomplish the initial estimation of pose between the vision sensors. Then, the 3D calibration points and the extrinsic parameters between vision sensors are further optimized via the bundle adjustment algorithm based on the distance and reprojection constraints. Experiments were conducted to validate the performance and the experimental results demonstrate that the distance error can be decreased from 3.5 mm to 0.8 mm after introducing the distance and reprojection constraints.

scholarly journals Conic tangents based high precision extraction method of concentric circle centers and its application in camera parameters calibration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fei Hao ◽  
Jinjiang Su ◽  
Jingjing Shi ◽  
Chaohan Zhu ◽  
Jiatong Song ◽  
...  
Keyword(s):  
High Precision ◽  
Calibration Method ◽  
Concentric Circle ◽  
Calibration Target ◽  
Factors Affecting ◽  
Straight Line Passing ◽  
Physical Experiments ◽  
Straight Line ◽  
Concentric Circles ◽  
The Right

AbstractA high-precision camera intrinsic parameters calibration method based on concentric circles was proposed. Different from Zhang’s method, its feature points are the centers of concentric circles. First, the collinearity of the projection of the center of concentric circles and the centers of two ellipses which are imaged from the concentric circles was proved. Subsequently, a straight line passing through the center of concentric circles was determined with four tangent lines of concentric circles. Finally, the projection of the center of concentric circles was extracted with the intersection of the straight line and the line determined by the two ellipse centers. Simulation and physical experiments are carried out to analyze the factors affecting the accuracy of circle center coordinate extraction and the results show that the accuracy of the proposed method is higher. On this basis, several key parameters of the calibration target design are determined through simulation experiments and then the calibration target is printed to calibrate a binocular system. The results show that the total reprojection error of the left camera is reduced by 17.66% and that of the right camera is reduced by 21.58% compared with those of Zhang’s method. Therefore, the proposed calibration method has higher accuracy.

A global calibration method for multiple vision sensors based on multiple targets

2011 ◽  
Vol 22 (12) ◽  
pp. 125102 ◽  
Author(s):  
Zhen Liu ◽  
Guangjun Zhang ◽  
Zhenzhong Wei ◽  
Junhua Sun
Keyword(s):  
Calibration Method ◽  
Multiple Targets ◽  
Global Calibration ◽  
Vision Sensors

scholarly journals I’m No Superman: fostering physician resilience through guided group discussion of Scrubs

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Arthur Holtzclaw ◽  
Jack Ellis ◽  
Christopher Colombo
Keyword(s):  
Internal Medicine ◽  
Training Programs ◽  
Low Cost ◽  
Group Discussion ◽  
Well Being ◽  
Internal Medicine Residency ◽  
Resiliency Training ◽  
High Satisfaction ◽  
Burn Out

Abstract Background Almost half of trainees experience burnout during their career. Despite the Accreditation Council on Graduate Medical Education (ACGME) recommendation that training programs enact well-being curricula, there is no proven method of addressing this difficult topic. Methods We created a curriculum addressing physician resiliency and well-being, designed for an Internal Medicine Residency Program. This curriculum utilized episodes from a medical television series, Scrubs, to facilitate a monthly, 1-h faculty guided discussion group. We collected informal feedback and abbreviated Maslach Burnout Inventories (aMBI) monthly and conducted a formal focus group after 6 months to gauge its effectiveness. Results The curriculum was successfully conducted for 12 months with each session averaging 18–20 residents. Residents reported high satisfaction, stating it was more enjoyable and helpful than traditional resiliency training. 19 of 24 residents (79 %) completed a baseline aMBI, and 17 of 20 residents (85 %) who attended the most recent session completed the 6-month follow-up, showing a non-significant 1-point improvement in all subsets of the aMBI. Conclusions This novel, low-cost, easily implemented curriculum addressed resiliency and burn-out in an Internal Medicine Residency. It was extremely well received and can easily be expanded to other training programs or to providers outside of training.

scholarly journals Current role of ultrasound in hemodialysis access evaluation

2021 ◽  
pp. 112972982110346
Author(s):  
Meola Mario ◽  
Jose Ibeas ◽  
Jan Malik
Keyword(s):  
Turning Point ◽  
Point Of Care ◽  
Low Cost ◽  
Wireless Systems ◽  
Future Perspectives ◽  
Maturation Period ◽  
Surveillance Programs ◽  
Dialysis Nurses

Physical examination (PE) is considered the backbone before vascular access (VA) placement, during maturation period and for follow-up. However, it may be inadequate in identifying suitable vasculature, mainly in comorbid patients, or in detecting complications. This review highlights the advantages of ultrasound imaging to manage VA before placement, during maturation and follow-up. Furthermore, it analyses the future perspectives in evaluating early and late VA complications thank to the availability of multiparametric platforms, point of care of ultrasound, and portable/wireless systems. Technical improvements and low-cost systems should favor the widespread ultrasound-based VA surveillance programs. This significant turning point needs an adequate training of nephrologists and dialysis nurses and the standardization of exams, parameters, and procedures.

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