scholarly journals A Flexile and High Precision Calibration Method for Binocular Structured Light Scanning System

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jianying Yuan ◽  
Qiong Wang ◽  
Bailin Li
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
Reference Object ◽  
Scanning System ◽  
Structured Light Scanning ◽  
Extrinsic Parameters ◽  
Precision Level ◽  
The Cost

3D (three-dimensional) structured light scanning system is widely used in the field of reverse engineering, quality inspection, and so forth. Camera calibration is the key for scanning precision. Currently, 2D (two-dimensional) or 3D fine processed calibration reference object is usually applied for high calibration precision, which is difficult to operate and the cost is high. In this paper, a novel calibration method is proposed with a scale bar and some artificial coded targets placed randomly in the measuring volume. The principle of the proposed method is based on hierarchical self-calibration and bundle adjustment. We get initial intrinsic parameters from images. Initial extrinsic parameters in projective space are estimated with the method of factorization and then upgraded to Euclidean space with orthogonality of rotation matrix and rank 3 of the absolute quadric as constraint. Last, all camera parameters are refined through bundle adjustment. Real experiments show that the proposed method is robust, and has the same precision level as the result using delicate artificial reference object, but the hardware cost is very low compared with the current calibration method used in 3D structured light scanning system.

scholarly journals A High-Precision Registration Technology Based on Bundle Adjustment in Structured Light Scanning System

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jianying Yuan ◽  
Qiong Wang ◽  
Xiaoliang Jiang ◽  
Bailin Li
Keyword(s):  
High Precision ◽  
Large Scale ◽  
Structured Light ◽  
Bundle Adjustment ◽  
Scanning System ◽  
Control Points ◽  
Registration Method ◽  
Global Control ◽  
3D Data ◽  
Structured Light Scanning

The multiview 3D data registration precision will decrease with the increasing number of registrations when measuring a large scale object using structured light scanning. In this paper, we propose a high-precision registration method based on multiple view geometry theory in order to solve this problem. First, a multiview network is constructed during the scanning process. The bundle adjustment method from digital close range photogrammetry is used to optimize the multiview network to obtain high-precision global control points. After that, the 3D data under each local coordinate of each scan are registered with the global control points. The method overcomes the error accumulation in the traditional registration process and reduces the time consumption of the following 3D data global optimization. The multiview 3D scan registration precision and efficiency are increased. Experiments verify the effectiveness of the proposed algorithm.

scholarly journals A Calibration Method for a Self-Rotating, Linear-Structured-Light Scanning, Three-Dimensional Reconstruction System Based on Plane Constraints

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8359
Author(s):  
Jianping Zhao ◽  
Yong Cheng ◽  
Gen Cai ◽  
Shengbo He ◽  
Libing Liao ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Coordinate System ◽  
Structured Light ◽  
Three Dimensional ◽  
Calibration Method ◽  
The Self ◽  
Three Dimensional Reconstruction ◽  
Optimal Position ◽  
Structured Light Scanning ◽  
Dimensional Reconstruction

This paper proposes a calibration method for a self-rotating, linear-structured-light (LSL) scanning, three-dimensional reconstruction system based on plane constraints. The point cloud of plane target collected by the self-rotating, LSL scanning, 3D reconstruction system should be constrained to the basic principle of the plane equation; it can quickly and accurately calibrate the position parameters between the coordinate system of the LSL module and the coordinate system of the self-rotating, LSL scanning, 3D reconstruction system. Additionally, the transformation equation could be established with the calibrated optimal position parameters. This paper obtains the above-mentioned position parameters through experiments and uses the calibrated self-rotating, LSL scanning, 3D reconstruction system to perform three-dimensional scanning and reconstruction of the test piece. The experimental results show that the calibration method can effectively improve the measurement accuracy of the system.

scholarly journals Simultaneous Robot–World and Hand–Eye Calibration without a Calibration Object

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3949 ◽  
Author(s):  
Wei Li ◽  
Mingli Dong ◽  
Naiguang Lu ◽  
Xiaoping Lou ◽  
Peng Sun
Keyword(s):  
Three Dimensional ◽  
Real Data ◽  
Medical Robotics ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
Data Sets ◽  
Rigid Transformation ◽  
Validation Experiment ◽  
Dimensional Reconstruction ◽  
Sparse Bundle Adjustment

An extended robot–world and hand–eye calibration method is proposed in this paper to evaluate the transformation relationship between the camera and robot device. This approach could be performed for mobile or medical robotics applications, where precise, expensive, or unsterile calibration objects, or enough movement space, cannot be made available at the work site. Firstly, a mathematical model is established to formulate the robot-gripper-to-camera rigid transformation and robot-base-to-world rigid transformation using the Kronecker product. Subsequently, a sparse bundle adjustment is introduced for the optimization of robot–world and hand–eye calibration, as well as reconstruction results. Finally, a validation experiment including two kinds of real data sets is designed to demonstrate the effectiveness and accuracy of the proposed approach. The translation relative error of rigid transformation is less than 8/10,000 by a Denso robot in a movement range of 1.3 m × 1.3 m × 1.2 m. The distance measurement mean error after three-dimensional reconstruction is 0.13 mm.

scholarly journals Calibration Method for Line-Structured Light Three-Dimensional Measurements Based on a Single Circular Target

2022 ◽  
Vol 12 (2) ◽  
pp. 588
Author(s):  
Jun Wang ◽  
Xuexing Li
Keyword(s):  
Structured Light ◽  
Three Dimensional ◽  
Calibration Method ◽  
Optical Center ◽  
3D Measurements ◽  
Light Plane ◽  
Laser Projector ◽  
Dimensional Measurements ◽  
Intersection Points ◽  
Circular Target

Single circular targets are widely used as calibration objects during line-structured light three-dimensional (3D) measurements because they are versatile and easy to manufacture. This paper proposes a new calibration method for line-structured light 3D measurements based on a single circular target. First, the target is placed in several positions and illuminated by a light beam emitted from a laser projector. A camera captures the resulting images and extracts an elliptic fitting profile of the target and the laser stripe. Second, an elliptical cone equation defined by the elliptic fitting profile and optical center of the camera is established based on the projective geometry. By combining the obtained elliptical cone and the known diameter of the circular target, two possible positions and orientations of the circular target are determined and two groups of 3D intersection points between the light plane and the circular target are identified. Finally, the correct group of 3D intersection points is filtered and the light plane is progressively fitted. The accuracy and effectiveness of the proposed method are verified both theoretically and experimentally. The obtained results indicate that a calibration accuracy of 0.05 mm can be achieved for an 80 mm × 80 mm planar target.

Influence of Coating Spray on Surface Measurement Using 3D Optical Scanning Systems

2019 ◽  
Author(s):  
Yuhang Yang ◽  
Siyuan Chen ◽  
Letao Wang ◽  
Jingying He ◽  
Shang-Ming Wang ◽  
...  
Keyword(s):  
Structured Light ◽  
Spray Coating ◽  
Surface Measurement ◽  
Scanning System ◽  
3D Measurement ◽  
Optical Scanning ◽  
Wide Range ◽  
Structured Light Scanning ◽  
3D Measurement System ◽  
Scanning Systems

Abstract High-resolution 3D measurement is crucial for a wide range of applications in manufacturing. With the recent development of optical technologies, the performance of many 3D scanning systems has entered the practical range for object digitizing, reverse engineering, quality control, and many other manufacturing applications. In order to extend the measurement capability to reflective or transparent surfaces, a common practice for reducing the unwanted reflection and refraction is to coat the surfaces with micro-particle spray. There is, however, limited discussion about the influence of coating spray on the resulted measurement precision of 3D optical scanning systems, and due to lack of standardized procedure for spray coating, the variability caused by different operators in surface measurement remains to be examined. This paper investigates the 3D data acquisition of spray-coated surfaces with a structured-light scanning system through experiments and statistical analysis. Both surface roughness and spatial statistics are used to quantitatively evaluate the characteristics of the 3D measurement system. Gauge R&R study is conducted to determine measurement repeatability and reproducibility. The results demonstrate that both the number of spray pass and the skill of the individual operator can significantly affect the performance of the structured-light scanning system. Other pertinent suggestions for the operation of 3D optical scanning systems with spray coating are also provided.

Quantifying quality of 3D printed clay objects using a 3D structured light scanning system

2020 ◽  
Vol 32 ◽  
pp. 100987 ◽  
Author(s):  
Kwangwoo Wi ◽  
Vignesh Suresh ◽  
Kejin Wang ◽  
Beiwen Li ◽  
Hantang Qin
Keyword(s):  
Structured Light ◽  
Scanning System ◽  
Structured Light Scanning ◽  
3D Printed
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