scholarly journals Accurate binocular stereo underwater measurement method

2019 ◽  
Vol 16 (5) ◽  
pp. 172988141986446
Author(s):  
Xiaojun Wu ◽  
XingCan Tang
Keyword(s):  
Measurement Accuracy ◽  
Calibration Method ◽  
Correction Method ◽  
Image Correction ◽  
Underwater Imaging ◽  
Epipolar Constraint ◽  
Imaging Model ◽  
Internal Parameters ◽  
Extrinsic Parameters ◽  
Binocular Stereo

Light changes its direction of propagation before entering a camera enclosed in a waterproof housing owing to refraction, which means that perspective imaging models in the air cannot be directly used underwater. In this article, we propose an accurate binocular stereo measurement system in an underwater environment. First, based on the physical underwater imaging model without approximation and Tsai’s calibration method, the proposed system is calibrated to acquire the extrinsic parameters, as the internal parameters can be pre-calibrated in air. Then, based on the calibrated camera parameters, an image correction method is proposed to convert the underwater images to air images. Thus, the epipolar constraint can be used to search the matching point directly. The experimental results show that the proposed method in this article can effectively eliminate the effect of refraction in the binocular vision and the measurement accuracy can be compared with the measurement result in air.

Self-Calibration of a Binocular Stereo Rig with Varying Intrinsic and Extrinsic Parameters

2013 ◽  
Vol 694-697 ◽  
pp. 1896-1901
Author(s):  
Hong Zheng ◽  
Zhen Qiang Liu ◽  
Kai Zhang
Keyword(s):  
Synthetic Data ◽  
Singular Values ◽  
Calibration Method ◽  
Essential Matrix ◽  
Self Calibration ◽  
Extrinsic Parameters ◽  
Binocular Stereo ◽  
Transformation Relation ◽  
Computer Vision Applications ◽  
Intrinsic And Extrinsic Parameters

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.

Camera Calibration of Binocular Vision Based on Virtual 1D Target

2012 ◽  
Vol 605-607 ◽  
pp. 859-863
Author(s):  
Yu Bo Guo ◽  
Gang Chen ◽  
Dong Ye ◽  
Feng Yuan
Keyword(s):  
Binocular Vision ◽  
Constraint Equation ◽  
Calibration Method ◽  
Epipolar Constraint ◽  
Field Calibration ◽  
Extrinsic Parameter ◽  
Extrinsic Parameters ◽  
Virtual Target ◽  
Flexible Application ◽  
Easy Operation

A field calibration method based on virtual 1D target is proposed for the extrinsic parameters of binocular vision. A target is placed on high precision 1D lifting platform to create virtual 1D target through motions of lifting platform. Two cameras are used to obtain virtual target images of different positions and preliminarily achieve extrinsic parameter calibration of binocular vision based on epipolar constraint equation. Finally, the length of virtual 1-D target is used to optimize the extrinsic parameters. This method is featured with easy operation, flexible application and field calibration. The experimental results verify the feasibility of this calibration method and show it can yield high field calibration precision.

The Calibration of Binocular Stereo Measurement System Based on a Coded Model

2013 ◽  
Vol 397-400 ◽  
pp. 1695-1699
Author(s):  
Hong Ming Chen ◽  
Hui Zhang
Keyword(s):  
Measurement System ◽  
Standard Error ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
Target Point ◽  
Point Sets ◽  
Extrinsic Parameters ◽  
Binocular Stereo ◽  
Camera Coordinate System ◽  
Sparse Bundle Adjustment

A calibration method of binocular stereo measurement system is proposed based on a coded model. Target points are designed to be with the unique IDs which make the match of two pictures and the match of image points and 3D points reliable and stable. The intrinsic parameters of the two cameras are calculated precisely and the 3D target point sets are reconstructed in each camera coordinate system respectively by using the multiple view geometry constraint and a generic sparse bundle adjustment. Then the extrinsic parameters are calculated by using the rigid transform of the two 3D point sets. The accuracy of the re-projection results is 0.037 pixel of standard error.

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 ◽  
...  
Keyword(s):  
Real Time ◽  
Stereo Vision ◽  
Calibration Method ◽  
Euler Angles ◽  
Self Calibration ◽  
Binocular Stereo Vision ◽  
Short Period ◽  
Extrinsic Parameters ◽  
Binocular Stereo ◽  
3D Scene

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.

A Calibration Method of Binocular Stereo Vision System Based on Halcon

2014 ◽  
Vol 989-994 ◽  
pp. 3007-3010
Author(s):  
Zhi Xian Zhang ◽  
Zhen De Zhu
Keyword(s):  
Stereo Vision ◽  
Vision System ◽  
Calibration Method ◽  
Pinhole Camera ◽  
Camera Model ◽  
Stereo Vision System ◽  
Imaging Model ◽  
Binocular Stereo Vision ◽  
Calibration Experiment ◽  
Binocular Stereo

This paper describes the pinhole camera model combined with an area sensor and a regular lens and the imaging model of the binocular stereo vision system. Also a method to determine the internal and external parameters of a camera by transferring the coordinates three times is described. Then a calibration experiment is carried out with the Halcon calibration board which proved the method works. The method mentioned in this paper has laid a good foundation for measuring the size of objects with the binocular stereo vision system.

LED Display Image Correction Based on Computer Simulation

2012 ◽  
Vol 182-183 ◽  
pp. 1751-1755
Author(s):  
Xi Feng Zheng ◽  
Feng Chang
Keyword(s):  
Computer Simulation ◽  
Correction Method ◽  
Experimental Results ◽  
Image Correction ◽  
The Third

For the purposes of correcting the LED display image, a method based on computer simulation is proposed. First, the development of the LED display panel is introduced. Second, analyze the causes of the problem which image in LED display panel has serious high non-uniformity, and introduce the existed correction techniques which are used to reduce the non-uniformity of LED display image. Simultaneously, point out the ground for shortcomings of these techniques. Third, describe the principle of correction method based on computer simulation detail from two steps, which are the luminous collection and luminous copulation. Forth, describe the realization steps of this method in accordance with the third step. Finally, this method is supplied in a LED display panel, whose resolution is 640×480. Experimental results show that this method is able to reduce the non-uniformity of images from 11.06% to 0.98%..

scholarly journals Extrinsic Parameters Calibration Method of Cameras with Non-Overlapping Fields of View in Airborne Remote Sensing

2018 ◽  
Vol 10 (8) ◽  
pp. 1298 ◽  
Author(s):  
Lei Yin ◽  
Xiangjun Wang ◽  
Yubo Ni ◽  
Kai Zhou ◽  
Jilong Zhang
Keyword(s):  
Remote Sensing ◽  
Camera Calibration ◽  
Calibration Method ◽  
Optimization Method ◽  
Airborne Remote Sensing ◽  
Camera System ◽  
Translation Error ◽  
Camera Systems ◽  
Calibration Methods ◽  
Extrinsic Parameters

Multi-camera systems are widely used in the fields of airborne remote sensing and unmanned aerial vehicle imaging. The measurement precision of these systems depends on the accuracy of the extrinsic parameters. Therefore, it is important to accurately calibrate the extrinsic parameters between the onboard cameras. Unlike conventional multi-camera calibration methods with a common field of view (FOV), multi-camera calibration without overlapping FOVs has certain difficulties. In this paper, we propose a calibration method for a multi-camera system without common FOVs, which is used on aero photogrammetry. First, the extrinsic parameters of any two cameras in a multi-camera system is calibrated, and the extrinsic matrix is optimized by the re-projection error. Then, the extrinsic parameters of each camera are unified to the system reference coordinate system by using the global optimization method. A simulation experiment and a physical verification experiment are designed for the theoretical arithmetic. The experimental results show that this method is operable. The rotation error angle of the camera’s extrinsic parameters is less than 0.001rad and the translation error is less than 0.08 mm.

scholarly journals Vibration Error Correction for the FOGs-Based Measurement in a Drilling System Using an Extended Kalman Filter

2021 ◽  
Vol 11 (14) ◽  
pp. 6514
Author(s):  
Lu Wang ◽  
Yuanbiao Hu ◽  
Tao Wang ◽  
Baolin Liu
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Measurement Accuracy ◽  
Original Data ◽  
Calibration Method ◽  
Error Model ◽  
Nonlinear Error ◽  
Measurement While Drilling ◽  
Drilling System ◽  
Vibration Error

Fiber-optic gyroscopes (FOGs)-based Measurement While Drilling system (MWD) is a newly developed instrument to survey the borehole trajectory continuously and in real time. However, because of the strong vibration while drilling, the measurement accuracy of FOG-based MWD deteriorates. It is urgent to improve the measurement accuracy while drilling. Therefore, this paper proposes an innovative scheme for the vibration error of the FOG-based MWD. Firstly, the nonlinear error models for the FOGs and ACCs are established. Secondly, a 36-order Extended Kalman Filter (EKF) combined with a calibration method based on 24-position is designed to identify the coefficients in the error model. Moreover, in order to obtain a higher accurate error model, an iterative calibration method has been suggested to suppress calibration residuals. Finally, vibration experiments simulating the drilling vibration in the laboratory is implemented. Compared to the original data, compensated the linear error items, the error of 3D borehole trajectory can only be reduced by a ratio from 10% to 34%. While compensating for the nonlinear error items of the FOG-based MWD, the error of 3D borehole trajectory can be reduced by a ratio from 44.13% to 97.22%. In conclusion, compensation of the nonlinear error of FOG-based MWD could improve the trajectory survey accuracy under vibration.

Sign in / Sign up

Export Citation Format

Share Document