A Self-Calibration Method of Varying Internal Camera Parameters Based on Binocular Stereo Vision

Author(s):  
Zetao JiangLianggang Jia ◽  
Shutao Guo
Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3666 ◽  
Author(s):  
Yue Wang ◽  
Xiangjun Wang ◽  
Zijing Wan ◽  
Jiahao Zhang

Nowadays, binocular stereo vision (BSV) is extensively used in real-time 3D reconstruction, which requires cameras to quickly implement self-calibration. At present, the camera parameters are typically estimated through iterative optimization. The calibration accuracy is high, but the process is time consuming. Hence, a system of BSV with rotating and non-zooming cameras is established in this study, in which the cameras can rotate horizontally and vertically. The cameras’ intrinsic parameters and initial position are estimated in advance by using Zhang’s calibration method. Only the yaw rotation angle in the horizontal direction and pitch in the vertical direction for each camera should be obtained during rotation. Therefore, we present a novel self-calibration method by using a single feature point and transform the imaging model of the pitch and yaw into a quadratic equation of the tangent value of the pitch. The closed-form solutions of the pitch and yaw can be obtained with known approximate values, which avoid the iterative convergence problem. Computer simulation and physical experiments prove the feasibility of the proposed method. Additionally, we compare the proposed method with Zhang’s method. Our experimental data indicate that the averages of the absolute errors of the Euler angles and translation vectors relative to the reference values are less than 0.21° and 6.6 mm, respectively, and the averages of the relative errors of 3D reconstruction coordinates do not exceed 4.2%.


Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 621 ◽  
Author(s):  
Hesheng Yin ◽  
Zhe Ma ◽  
Ming Zhong ◽  
Kuan Wu ◽  
Yuteng Wei ◽  
...  

The calibration problem of binocular stereo vision rig is critical for its practical application. However, most existing calibration methods are based on manual off-line algorithms for specific reference targets or patterns. In this paper, we propose a novel simultaneous localization and mapping (SLAM)-based self-calibration method designed to achieve real-time, automatic and accurate calibration of the binocular stereo vision (BSV) rig’s extrinsic parameters in a short period without auxiliary equipment and special calibration markers, assuming the intrinsic parameters of the left and right cameras are known in advance. The main contribution of this paper is to use the SLAM algorithm as our main tool for the calibration method. The method mainly consists of two parts: SLAM-based construction of 3D scene point map and extrinsic parameter calibration. In the first part, the SLAM mainly constructs a 3D feature point map of the natural environment, which is used as a calibration area map. To improve the efficiency of calibration, a lightweight, real-time visual SLAM is built. In the second part, extrinsic parameters are calibrated through the 3D scene point map created by the SLAM. Ultimately, field experiments are performed to evaluate the feasibility, repeatability, and efficiency of our self-calibration method. The experimental data shows that the average absolute error of the Euler angles and translation vectors obtained by our method relative to the reference values obtained by Zhang’s calibration method does not exceed 0.5˚ and 2 mm, respectively. The distribution range of the most widely spread parameter in Euler angles is less than 0.2˚ while that in translation vectors does not exceed 2.15 mm. Under the general texture scene and the normal driving speed of the mobile robot, the calibration time can be generally maintained within 10 s. The above results prove that our proposed method is reliable and has practical value.


2013 ◽  
Vol 397-400 ◽  
pp. 1547-1551
Author(s):  
Hui Yu Xiang ◽  
Bao An Han ◽  
Zhe Li ◽  
Jia Jun Huang

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.


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

2015 ◽  
Vol 740 ◽  
pp. 531-534 ◽  
Author(s):  
Tao He ◽  
Jiu Yin Chen ◽  
Xiang Hu ◽  
Xian Wang

It is important to obtain the 3d coordinate in the field of measuring. How accurate, fast, convenient to obtain the 3d coordinate affects the accuracy and reliability of measurement directly. Through studying the basic theories of machine vision this paper focus on the study of a stereo vision measurement model based on the intersecting axis. In view of the parameters in the model of binocular stereo vision, this paper uses the Zhang Zhengyou calibration method to calibrate the system of Stereo vision. In order to test the accuracy of the system, this paper measures the distance of two standard circular. Finally, the machining experiment validates the proposed method.


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