scholarly journals A Convenient Calibration Method for LRF-Camera Combination Systems Based on a Checkerboard

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1315 ◽  
Author(s):  
Zhuang Zhang ◽  
Rujin Zhao ◽  
Enhai Liu ◽  
Kun Yan ◽  
Yuebo Ma
Keyword(s):  
Cost Function ◽  
High Precision ◽  
Measurement System ◽  
Calibration Method ◽  
Simulation Experiments ◽  
Extrinsic Parameters ◽  
Spatial Coordinates ◽  
Calibration Accuracy ◽  
Camera Parameters ◽  
2D And 3D

In this paper, a simple and easy high-precision calibration method is proposed for the LRF-camera combined measurement system which is widely used at present. This method can be applied not only to mainstream 2D and 3D LRF-cameras, but also to calibrate newly developed 1D LRF-camera combined systems. It only needs a calibration board to record at least three sets of data. First, the camera parameters and distortion coefficients are decoupled by the distortion center. Then, the spatial coordinates of laser spots are solved using line and plane constraints, and the estimation of LRF-camera extrinsic parameters is realized. In addition, we establish a cost function for optimizing the system. Finally, the calibration accuracy and characteristics of the method are analyzed through simulation experiments, and the validity of the method is verified through the calibration of a real system.

Research on Calibration Method of Linear Structured Light Vision Measurement System

2014 ◽  
Vol 644-650 ◽  
pp. 1234-1239
Author(s):  
Tao He ◽  
Yu Lang Xie ◽  
Cai Sheng Zhu ◽  
Jiu Yin Chen
Keyword(s):  
High Precision ◽  
Measurement System ◽  
Structured Light ◽  
Target Position ◽  
Calibration Method ◽  
Measurement Model ◽  
Sensor Calibration ◽  
Vision Measurement ◽  
Set Up ◽  
Structured Light Vision

This template explains and demonstrates how to design a measurement system based on the size of the linear structured light vision, the system could works at realized the high precision and fast measurement of the size of mechanical parts, and accurate calibration of the system. First of all, this paper set up the experimental platform based on linear structured light vision measurement. Secondly, this paper established a system of measurement model, and puts forward a new method of calibration of structured light sensor and set up the mathematical model of sensor calibration. This calibration method only need to use some gage blocks of high precision as the target, the target position need not have a strict requirements, and the solving process will be more convenient, much easier to field use and maintenance. Finally, measuring accuracy on the system by gage blocks with high precision is verified, the experiment shows that measurement accuracy within 0.050 mmin the depth of 0-80 - mm range. This system can satisfy the demands of precision testing of most industrial parts .with its simple calibration process and high precision, it is suitable for the structured light vision calibration.

Calibration Method for Mapping Camera Based on a Precise Grouped Approach Method

2018 ◽  
Vol 32 (11) ◽  
pp. 1855019 ◽  
Author(s):  
Lina Zheng ◽  
Guoqin Yuan ◽  
Xue Leng ◽  
Yingfeng Wu
Keyword(s):  
High Precision ◽  
Calibration Method ◽  
Identical Experimental Condition ◽  
Zero Position ◽  
Approach Method ◽  
Calibration Accuracy ◽  
Angle Method ◽  
Rotation Stage

This paper introduces a new calibration method for the mapping camera called Precise Grouped Approach Method (PGAM). The conventional calibration method for the mapping camera is the exact measuring angle method. The accuracy of this method can be reduced by theoretical uncertainties and the number and distribution of observation points. PGAM is able to overcome these disadvantages and improve the accuracy. Firstly, we reduce the theoretical uncertainties by means of a grouped approach method, which rectifies the high-precision rotation stage to zero position. Secondly, a weighted theory is applied to eliminate the effect of the number and distribution of observation points. Finally, the accuracy of PGAM is analyzed. The experiment result shows that the calibration accuracy is significantly improved when using the proposed PGAM algorithm, compared to the conventional one under the identical experimental condition.

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 METHOD OF AIRBORNE SAR RADIATION CALIBRATION BASED ON POINT TARGET

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 123-128
Author(s):  
S. Yang ◽  
Z. Xu ◽  
C. Cheng
Keyword(s):  
High Precision ◽  
Integral Method ◽  
Calibration Method ◽  
Antenna Pattern ◽  
Sinc Function ◽  
Sar Images ◽  
Key Technology ◽  
Point Target ◽  
Calibration Accuracy ◽  
Airborne Sar

Abstract. Radiation calibration of airborne SAR images is the basis for realizing the quantitative processing of airborne SAR images. Radiation calibration based on point targets is a general and convenient method. However, high precision is still the goal of improving the current point target SAR radiation calibration. For the key technology of high-precision radiation calibration processing for airborne SAR images, this paper uses the integral method and the peak method to calculate the point target radiation response energy, By analysing the radiation characteristics of the SAR image and comparing the methods, the sinc function model is used to fit the corrected antenna pattern. Combined with the radar power equation to solve the calibration constant, the complete point target radiation calibration method and process are established, and the different methods in the key technology are compared and analysed. The results show that the calibration method combined with the energy calculation model of the integral method and the sinc function antenna pattern correction model can achieve higher relative and absolute calibration accuracy. The optimized method can meet and exceed the requirements for radiometric calibration accuracy for high-resolution airborne SAR applications.

scholarly journals Calibration Method for Angular Positioning Deviation of a High-Precision Rotary Table Based on the Laser Tracer Multi-Station Measurement System

2019 ◽  
Vol 9 (16) ◽  
pp. 3417 ◽  
Author(s):  
Hongfang Chen ◽  
Bo Jiang ◽  
Hu Lin ◽  
Shuang Zhang ◽  
Zhaoyao Shi ◽  
...  
Keyword(s):  
High Precision ◽  
Measurement System ◽  
Calibration Method ◽  
Optimization Method ◽  
Rotary Table ◽  
Work Surface ◽  
Marquardt Algorithm ◽  
Angular Interval ◽  
Relationship Model ◽  
Value Decomposition

This paper proposes a calibration method for angular positioning deviation of a high-precision rotary table based on the laser tracer multi-station measurement system. The algorithm error of the calibration method for angular positioning deviation of a high-precision rotary table based on the laser tracer multi-station measurement system was mainly discussed. During the experiments, the laser tracer was fixed on the work surface of the rotary table, and the rotary was fixed on the work surface of the coordinate measurement machine (CMM). The rotary table was rotated with the same angular interval. In this case, an optimization method for calculating the coordinates of a laser tracer station by using Levenberg–Marquardt algorithm and singular value decomposition transform was proposed. Then, the angular positioning deviation of the rotary table was calibrated by an established geometric relationship model between the coordinates of laser tracer stations and the rotation angle of the rotary table. The angular positioning deviation of the high-precision rotary table was as low as ±0.9″, and the error of the calibration method was ±0.4″. The experimental results proved the feasibility of the proposed calibration method. The calibration method proposed in this paper is suitable for the case that the rotary table is not linked with the CMM, especially for large high-precision rotary tables.

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 Constrained Multiple Planar Reconstruction for Automatic Camera Calibration of Intelligent Vehicles

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4643
Author(s):  
Sang Jun Lee ◽  
Jeawoo Lee ◽  
Wonju Lee ◽  
Cheolhun Jang
Keyword(s):  
Camera Calibration ◽  
Calibration Method ◽  
Image Features ◽  
Intelligent Vehicles ◽  
Point Problem ◽  
Reconstruction Method ◽  
Calibration Methods ◽  
The World ◽  
Extrinsic Parameters ◽  
Automatic Camera Calibration

In intelligent vehicles, extrinsic camera calibration is preferable to be conducted on a regular basis to deal with unpredictable mechanical changes or variations on weight load distribution. Specifically, high-precision extrinsic parameters between the camera coordinate and the world coordinate are essential to implement high-level functions in intelligent vehicles such as distance estimation and lane departure warning. However, conventional calibration methods, which solve a Perspective-n-Point problem, require laborious work to measure the positions of 3D points in the world coordinate. To reduce this inconvenience, this paper proposes an automatic camera calibration method based on 3D reconstruction. The main contribution of this paper is a novel reconstruction method to recover 3D points on planes perpendicular to the ground. The proposed method jointly optimizes reprojection errors of image features projected from multiple planar surfaces, and finally, it significantly reduces errors in camera extrinsic parameters. Experiments were conducted in synthetic simulation and real calibration environments to demonstrate the effectiveness of the proposed method.

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