A robot hand-eye calibration method of line laser sensor based on 3D reconstruction

2021 ◽  
Vol 71 ◽  
pp. 102136
Author(s):  
Mingyang Li ◽  
Zhijiang Du ◽  
Xiaoxing Ma ◽  
Wei Dong ◽  
Yongzhuo Gao
Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 765
Author(s):  
Hugo Álvarez ◽  
Marcos Alonso ◽  
Jairo R. Sánchez ◽  
Alberto Izaguirre

This paper describes a method for calibrating multi camera and multi laser 3D triangulation systems, particularly for those using Scheimpflug adapters. Under this configuration, the focus plane of the camera is located at the laser plane, making it difficult to use traditional calibration methods, such as chessboard pattern-based strategies. Our method uses a conical calibration object whose intersections with the laser planes generate stepped line patterns that can be used to calculate the camera-laser homographies. The calibration object has been designed to calibrate scanners for revolving surfaces, but it can be easily extended to linear setups. The experiments carried out show that the proposed system has a precision of 0.1 mm.


Author(s):  
Huanbing Gao ◽  
Lei Liu ◽  
Ya Tian ◽  
Shouyin Lu

This paper presented 3D reconstruction method for road scene with the help of obstacle detection. 3D reconstruction for road scene can be used in autonomous driving, driver assistance system, car navigation systems. However, some errors often rose when 3D reconstructing due to the shade from the moving object in the road scene. The presented 3D reconstruction method with obstacle detection feedback can avoid this problem. Firstly, this paper offers a framework for the 3D reconstruction of road scene by laser scanning and vision. A calibration method based on the location of horizon is proposed, and a method of attitude angle measuring based on vanishing point is proposed to revise the 3D reconstruction result. Secondly, the reconstruction framework is extended by integrating with an object recognition that can automatically detect and discriminate obstacles in the input video streams by a RANSAC approach and threshold filter, and localizes them in the 3D model. 3D reconstruction and obstacle detection are tightly integrated and benefit from each other. The experiment result verified the feasibility and practicability of the proposed method.


Author(s):  
Hua-Gang Liang ◽  
Wen-Xiu Qian ◽  
Yong-Kui Liu ◽  
Feng Ru

In this paper, a method of 3D reconstruction from two images acquired by two panoramic cameras is presented. Firstly, the features of the reconstruction object detected in each image are matched through the DP matching method. Secondly, optical correction is carried out on two cameras, and the internal parameters of panoramic cameras can be calculated. Finally, according to the calibration method, the geometric relationship between corresponding points in space and in two panoramic images is deduced. The results indicate that the method of 3D reconstruction based on two panoramic cameras is simple, and the accuracy can reach 98.82%.


Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1083 ◽  
Author(s):  
Jiehu Kang ◽  
Bin Wu ◽  
Xiaodeng Duan ◽  
Ting Xue

The articulated laser sensor is a new kind of trans-scale and non-contact measurement instrument in regular-size space and industrial applications. These sensors overcome many deficiencies and application limitations of traditional measurement methods. The articulated laser sensor consists of two articulated laser sensing modules, and each module is made up of two rotary tables and one collimated laser. The three axes represent a non-orthogonal shaft architecture. The calibration method of system parameters for traditional instruments is no longer suitable. A novel high-accuracy calibration method of an articulated laser sensor for trans-scale 3D measurement is proposed. Based on perspective projection models and image processing techniques, the calibration method of the laser beam is the key innovative aspect of this study and is introduced in detail. The experimental results show that a maximum distance error of 0.05 mm was detected with the articulated laser sensor. We demonstrate that the proposed high-accuracy calibration method is feasible and effective, particularly for the calibration of laser beams.


Author(s):  
Jiaqi Ye ◽  
Edward Stewart ◽  
Clive Roberts

In recent decades, 3D reconstruction techniques have been applied in an increasing number of areas such as virtual reality, robot navigation, medical imaging and architectural restoration of cultural relics. Most of the inspection techniques used in railway systems are, however, still implemented on a 2D basis. This is particularly true of track inspection due to its linear nature. Benefiting from the development of sensor technology and constantly improving processors, higher quality 3D model reconstructions are becoming possible which push the technology into more challenging areas. One such advancement is the use of 3D perceptual techniques in railway systems. This paper presents a novel 3D perceptual system, based on a low-cost 2D laser sensor, which has been developed for the detection and characterisation of physical surface defects in railway tracks. An innovative prototype system has been developed to capture and correlate the laser scan data; dedicated 3D data processing procedures have then been developed in the form of three specific defect-detection algorithms (depth gradient, face normal and face-normal gradient) which are applied to the 3D model. The system has been tested with rail samples in the laboratory and at the Long Marston Railway Test Track. The 3D models developed represent the external surface of the samples both laterally (2D slices) and longitudinally (3D model), and common surface defects can be detected and represented in 3D. The results demonstrate the feasibility of applying 3D reconstruction-based inspection techniques to railway systems.


2020 ◽  
Author(s):  
Jiangping Qin ◽  
Zhaolong Li ◽  
Bo Sun ◽  
Feng Yu ◽  
Yi Liu ◽  
...  

Abstract With the popularization of automounting robots in protein crystal diffraction experiment beamline stations, the coordinate calibration of the robot sample mounting position has become an inevitable task in the daily maintenance of the beamline station. In this method, the image features of the laser sensor spot and goniometer are extracted by color extraction and edge detection, respectively, and the noise is eliminated by median filtering. Then, after locating the pixel coordinates of the center of the circle through the Hough circle detection and the minimum closed circle fitting algorithm, the coordinates in the base coordinate system are obtained using the camera internal and external parameter matrices and the hand-eye relationship matrix. Finally, according to the deviation of the laser spot and the visual positioning coordinate of the goniometer, the position of the robot is compensated to improve the positioning accuracy, and the automatic calibration of the sample point is realized.


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%.


Author(s):  
Qiangfeng Wang ◽  
Yan Cao ◽  
Yu Bai ◽  
Yujia Wu ◽  
Qingyun Wu

In this paper, the three-dimensional (3D) reconstruction of target self-calibrating system for the guidance system of air-to-air missile is researched. The basic ideology of self-calibrating theory is studied in depth and also the advantages and disadvantages of traditional calibration method, which is based on active vision and target self-calibrating method, are listed for comparison. The mathematical model of the perspective camera is established, and on this basis, the camera parameters are figured out combining with LM optimization algorithm. The reconstruction is conducted by the method of stratified calibrating. It is proved that the theory of 3D reconstruction of target self-calibrating system in air to air missile is available according to the experimental results. It puts forward a new research approach for the guidance system of air to air missile to identify the target characteristic information in different azimuths.


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