An improved two-point calibration method for stereo vision with rotating cameras in large FOV

2019 ◽  
Vol 66 (10) ◽  
pp. 1106-1115 ◽  
Author(s):  
Yue Wang ◽  
Xiangjun Wang
Keyword(s):  
Stereo Vision ◽  
Calibration Method

Novel Calibration Method for Stereo Vision Sensor Using Flexible Target

2013 ◽  
Vol 33 (3) ◽  
pp. 0315001
Author(s):  
刘震 Liu Zhen ◽  
尚砚娜 Shang Yanna
Keyword(s):  
Stereo Vision ◽  
Calibration Method ◽  
Vision Sensor

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.

Binocular Stereo Vision Calibration System Implementation of Grid Strain Measurement in Sheet Forming

2013 ◽  
Vol 397-400 ◽  
pp. 1547-1551
Author(s):  
Hui Yu Xiang ◽  
Bao An Han ◽  
Zhe Li ◽  
Jia Jun Huang
Keyword(s):  
Stereo Vision ◽  
Strain Measurement ◽  
Calibration Method ◽  
Sheet Forming ◽  
Calibration System ◽  
Camera Model ◽  
Distortion Factor ◽  
Binocular Stereo Vision ◽  
Binocular Stereo ◽  
Stereo Calibration

For the research of camera calibration in the system of grid strain measurement in sheet forming, the pinhole camera model, the nonlinear model of the camera and the binocular stereo model are analyzed, drawing a binocular stereo calibration method based on HALCON, which detailedly describes the calibration principle and specific calibration process. A binocular stereo vision calibration system based on VC6.0 is established, by which the influence on camera focus, distortion factor and principle points from the number of calibration images is verified by experiments.

Projector calibration method based on stereo vision system

2017 ◽  
Vol 24 (6) ◽  
pp. 727-733 ◽  
Author(s):  
Shourui Yang ◽  
Miao Liu ◽  
Jiahui Song ◽  
Shibin Yin ◽  
Yin Guo ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Vision System ◽  
Calibration Method ◽  
Stereo Vision System ◽  
Projector Calibration

The Calibration Method of a stereo-Vision-Based Coordinates Measurement System via a Two-Axis Turntable--The Combination of Stereo Vision and Turntable

2021 ◽  
Vol 14 ◽  
Author(s):  
Zimiao Zhang ◽  
Zhiwu Wang ◽  
Shihai Zhang ◽  
Anqi Fu
Keyword(s):  
Stereo Vision ◽  
Measurement System ◽  
Vision System ◽  
Three Dimensional ◽  
Calibration Method ◽  
Measurement Range ◽  
Measurement Technology ◽  
Rotation Axes ◽  
Internal Parameters ◽  
Calibration Methods

Background: Stereo-vision-based three-dimensional coordinates measurement technology has been widely applied in the military or civil fields. There are two problems that need to be solved. The first problem is that each camera internal parameters and the two cameras external parameters need to be calibrated. To increase the measurement range, usually the turntable is used with the stereo vision system together. The second problem is the calibration of the turntable. Objective: The aim of the study is to construct and calibrate a stereo-vision-based coordinates measurement system via a two-axis turntable. Methods: Considering that the internal parameters of each camera do not change during the measurement process and the complicated optimization process of one-step self-calibration, a two-step stereo vision calibration method is proposed. In the first step, we calibrate the internal parameters of each camera through a specially designed planar target with circular points. In the second step, on the basis of the calibrated results of the internal parameters, the two cameras external parameters are calibrated through a simple target which could be distributed in the measurement volume. For the calibration of the two-axis turntable, we calibrated the rotation axes of the turntable and the coordinates of points in the 3D space could be measured considering the non-orthogonality of the axes. Results: Some experiments are provided to examine the calibration methods we proposed. They are the plane target measurement experiments, the standard ball center coordinates measurement experiments and target pose measurement experiments. Experiment results demonstrate the superiority of the calibration method we proposed. Conclusion: We studied the calibration methods of the stereo-vision-based coordinates measurement system via a two-axis turntable. The experimental results show the measurement accuracy of our system is less than 0.1mm.

Improved Zhang′s Calibration Method and Experiments for Underwater Binocular Stereo-Vision

2014 ◽  
Vol 34 (12) ◽  
pp. 1215006 ◽  
Author(s):  
李光乐 Li Guangle ◽  
黄文有 Huang Wenyou ◽  
刘青松 Liu Qingsong ◽  
邓志燕 Deng Zhiyan
Keyword(s):  
Stereo Vision ◽  
Calibration Method ◽  
Binocular Stereo Vision ◽  
Binocular Stereo

The Comparison of Two Stereo Vision Sensor Calibration Methods

2011 ◽  
Vol 317-319 ◽  
pp. 397-400
Author(s):  
Gang Chen ◽  
Hua Chen ◽  
Yu Bo Guo ◽  
Dong Ye
Keyword(s):  
Stereo Vision ◽  
Nonlinear Distortion ◽  
Calibration Method ◽  
Sensor Calibration ◽  
Vision Sensor ◽  
Calibration Methods ◽  
Hole Model ◽  
Draw Conclusion

This paper presents and comparison two stereo vision sensor calibration methods: Volume template based calibration method and the calibration based on virtual stereo pattern. First method use a premade volume template. Second method use a group of random spatial points that are formed by an infrared LED moved with the probe of CMM. Two methods adopt an ideal pin-hole model that ignores the nonlinear distortion of the cameras. Through compare two calibratioin methods, we can draw conclusion that the first method can be applide to stereo sensor calibration in measurement field and the second method could gain higher calibrating precision.

scholarly journals A Stereo-Vision System for Measuring the Ram Speed of Steam Hammers in an Environment with a Large Field of View and Strong Vibrations

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 996 ◽  
Author(s):  
Ran Chen ◽  
Zhongwei Li ◽  
Kai Zhong ◽  
Xingjian Liu ◽  
Yonghui Wu ◽  
...  
Keyword(s):  
Stereo Vision ◽  
High Speed ◽  
Vision System ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
Field Of View ◽  
Large Field ◽  
Practical Applications ◽  
Accuracy Of Measurements ◽  
Ram Speed

The ram speed of a steam hammer is an important parameter that directly affects the forming performance of forgers. This parameter must be monitored regularly in practical applications in industry. Because of the complex and dangerous industrial environment of forging equipment, non-contact measurement methods, such as stereo vision, might be optimal. However, in actual application, the field of view (FOV) required to measure the steam hammer is extremely large, with a value of 2–3 m, and heavy steam hammer, at high-speed, usually causes a strong vibration. These two factors combine to sacrifice the accuracy of measurements, and can even cause the failure of measurements. To solve these issues, a bundle-adjustment-principle-based system calibration method is proposed to realize high-accuracy calibration for a large FOV, which can obtain accurate calibration results when the calibration target is not precisely manufactured. To decrease the influence of strong vibration, a stationary world coordinate system was built, and the external parameters were recalibrated during the entire measurement process. The accuracy and effectiveness of the proposed technique were verified by an experiment to measure the ram speed of a counterblow steam hammer in a die forging device.

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