scholarly journals SLAM-Based Self-Calibration of a Binocular Stereo Vision Rig in Real-Time

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.

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%.


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.


10.5772/50921 ◽  
2012 ◽  
Vol 9 (1) ◽  
pp. 26 ◽  
Author(s):  
Xiao-Bo Lai ◽  
Hai-Shun Wang ◽  
Yue-Hong Xu

To acquire range information for mobile robots, a TMS320DM642 DSP-based range finding system with binocular stereo vision is proposed. Firstly, paired images of the target are captured and a Gaussian filter, as well as improved Sobel kernels, are achieved. Secondly, a feature-based local stereo matching algorithm is performed so that the space location of the target can be determined. Finally, in order to improve the reliability and robustness of the stereo matching algorithm under complex conditions, the confidence filter and the left-right consistency filter are investigated to eliminate the mismatching points. In addition, the range finding algorithm is implemented in the DSP/BIOS operating system to gain real-time control. Experimental results show that the average accuracy of range finding is more than 99% for measuring single-point distances equal to 120cm in the simple scenario and the algorithm takes about 39ms for ranging a time in a complex scenario. The effectivity, as well as the feasibility, of the proposed range finding system are verified.


2013 ◽  
Vol 694-697 ◽  
pp. 1896-1901
Author(s):  
Hong Zheng ◽  
Zhen Qiang Liu ◽  
Kai Zhang

Self-calibration of stereo rig is essential to many computer vision applications. In this paper, a new self-calibration method is proposed for a binocular stereo rig undergoing a single motion with varying intrinsic and extrinsic parameters. Firstly, we build up a stereo rig model based on the basic platform to describe the transformation of the stereo rig during the motion. Secondly, the characteristics of singular values of the essential matrix are used to estimate the intrinsic parameters of camera. Finally, analyzing the transformation relation between different views, the relative position of cameras and motion of the stereo rig are estimated. Experimental results for both synthetic data and real images are provided to show the performance of the proposed method.


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

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