scholarly journals Flexible and Accurate Calibration Method for Non-Overlapping Vision Sensors Based on Distance and Reprojection Constraints

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4623 ◽  
Author(s):  
Tao Jiang ◽  
Xu Chen ◽  
Qiang Chen ◽  
Zhe Jiang
Keyword(s):  
Calibration Method ◽  
Bundle Adjustment ◽  
Experimental Results ◽  
Laser Tracker ◽  
Distance Error ◽  
Global Calibration ◽  
Vision Sensors ◽  
Extrinsic Parameters ◽  
Calibration Pattern

This paper addresses the problem of flexible and accurate global calibration for multiple non-overlapping vision sensors in a confined workspace. Instead of using an auxiliary calibration pattern, the proposed method uses one laser tracker and only its accessory target sphere to obtain all the 3D calibration points and then accomplish the initial estimation of pose between the vision sensors. Then, the 3D calibration points and the extrinsic parameters between vision sensors are further optimized via the bundle adjustment algorithm based on the distance and reprojection constraints. Experiments were conducted to validate the performance and the experimental results demonstrate that the distance error can be decreased from 3.5 mm to 0.8 mm after introducing the distance and reprojection constraints.

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 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.

A global calibration method for multiple vision sensors based on multiple targets

2011 ◽  
Vol 22 (12) ◽  
pp. 125102 ◽  
Author(s):  
Zhen Liu ◽  
Guangjun Zhang ◽  
Zhenzhong Wei ◽  
Junhua Sun
Keyword(s):  
Calibration Method ◽  
Multiple Targets ◽  
Global Calibration ◽  
Vision Sensors

Calibration of Large Scale Coordinate Measuring System Based on Scanning Laser Plane

2012 ◽  
Vol 503-504 ◽  
pp. 1270-1275 ◽  
Author(s):  
Da Bao Lao ◽  
Wei Hu Zhou ◽  
Zi Li Zhang ◽  
Xue You Yang ◽  
Ji Gui Zhu
Keyword(s):  
Large Scale ◽  
Calibration Method ◽  
Measurement Model ◽  
Bundle Adjustment ◽  
Measuring System ◽  
Coordinate Frame ◽  
Coordinate Measurement ◽  
Global Calibration ◽  
Planar Laser ◽  
Measuring Network

To overcome the disadvantages of existing large-scale coordinate measurement systems about low level of automation and poor parallelism, this paper introduces a novel system which characters multi-sensor measuring network, while a single sensor measures angle via a couple of non-parallel planar laser beams rotating around a fixed shaft. The novel method for measuring angle improves automation in large-scale coordinate measurement. Furthermore, measuring network assures that measurement accuracy keeps to the same level even when the measuring range is enlarged. Measurement model and calibration are the key technologies of the system. They are the main sources of measuring errors. Therefore, to minimize the error, a practical global calibration method for the multi-sensor network system is proposed, with constructing a precise mathematical model. In this model, the parameters of the system are divided to inner and outer parts. While the inner parameters are obtained by aided instrument, the outer which means transform parameters between different sensors are figured out in spot calibration. Finally, the objective function based on transform coefficients between different sensor coordinate systems is defined and the outer parameters are optimized by bundle adjustment method. Thus, the whole system can finish global calibration by one time，and no medi-coordinate-frame is needed．Therewith，transformation time of coordinate frame decreases and calibration process is facilitated. Finally，measurement experiments are conducted with root mean square(RMS) error of not more than 0.1 mm.

scholarly journals Pembuatan Virtual Tour pada Situs Sejarah Indonesia Menggunakan Crowdsourcing Foto Digital untuk Mempromosikan Situs Sejarah Nusantara

Jurnal INFORM ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Anggit Wikanningrum
Keyword(s):  
Digital Video ◽  
Digital Camera ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
The Other ◽  
Web Based ◽  
Extrinsic Parameters ◽  
History Of ◽  
Historical Sites ◽  
Intrinsic And Extrinsic Parameters

Abstract — Promotion of the site's history is one of the important factors for the preservation of the archipelago history. The barrier faced to do is that site promotional media nusantara history which does not draw as well as the expensivecost of publication on media advertising. One of methods that can be used is by utilizing digital photos or digital video taken on historical sites and combines them to form a network of relationships between the photos. User can navigate to look around the history site so it can be used as media promotion. The method used for the incorporation of digital photographs or digital video is a method of bundle adjustment and auto camera calibration. Bundle adjustment is a method used to predict the position of the camera relative to the other cameras, while the auto calibration method of camera was used to predict the intrinsic and extrinsic parameters of digital camera used. By using both of these methods and software for web-based navigation, can be used as media promotion of the history of the archipelago which is interesting, easy, and covering the whole of the history section of the site.

A Global Calibration Method of Multi-Vision Sensors in the Measurement of Engine Cylinder Joint Surface Holes

2011 ◽  
Vol 467-469 ◽  
pp. 1182-1188 ◽  
Author(s):  
Yong Qiang Shi ◽  
Chang Ku Sun ◽  
Bao Guang Wang ◽  
Peng Wang ◽  
Hong Xu Duan
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Calibration Method ◽  
Joint Surface ◽  
Calibration Target ◽  
Whole Process ◽  
Global Calibration ◽  
Vision Sensors ◽  
Engine Cylinder

The measurement of engine cylinder joint surface holes is directly related to the control of product quality and the follow-up assembly. CMM is widely used in this field but can not meet the inspection requirements of automation, rapidity and Online testing. In this paper, a new measurement scheme based on the combination of multi-vision sensors is proposed. The global calibration method is focused on and a new dedicated calibration target is designed. The whole process of the system global calibration can be accomplished quickly through single imaging. The experiment results show that the method is feasible and with high precision. The method mentioned above can satisfy the engine production line requirements of intelligence, rapidity, high precision and low cost.

Kinematic Calibration Method of Robots Based on Distance Error

ROBOT ◽  
2013 ◽  
Vol 35 (5) ◽  
pp. 600 ◽  
Author(s):  
Wenbin GAO ◽  
Hongguang WANG ◽  
Yong JIANG ◽  
Xin'an PAN
Keyword(s):  
Calibration Method ◽  
Kinematic Calibration ◽  
Distance Error

scholarly journals Optimization-Based Online Initialization and Calibration of Monocular Visual-Inertial Odometry Considering Spatial-Temporal Constraints

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2673
Author(s):  
Weibo Huang ◽  
Weiwei Wan ◽  
Hong Liu
Keyword(s):  
Measurement Data ◽  
Calibration Method ◽  
Bundle Adjustment ◽  
Measurement Unit ◽  
Temporal Parameters ◽  
Work Routine ◽  
Initial States ◽  
Time Offset ◽  
Public Datasets ◽  
Metric Scale

The online system state initialization and simultaneous spatial-temporal calibration are critical for monocular Visual-Inertial Odometry (VIO) since these parameters are either not well provided or even unknown. Although impressive performance has been achieved, most of the existing methods are designed for filter-based VIOs. For the optimization-based VIOs, there is not much online spatial-temporal calibration method in the literature. In this paper, we propose an optimization-based online initialization and spatial-temporal calibration method for VIO. The method does not need any prior knowledge about spatial and temporal configurations. It estimates the initial states of metric-scale, velocity, gravity, Inertial Measurement Unit (IMU) biases, and calibrates the coordinate transformation and time offsets between the camera and IMU sensors. The work routine of the method is as follows. First, it uses a time offset model and two short-term motion interpolation algorithms to align and interpolate the camera and IMU measurement data. Then, the aligned and interpolated results are sent to an incremental estimator to estimate the initial states and the spatial–temporal parameters. After that, a bundle adjustment is additionally included to improve the accuracy of the estimated results. Experiments using both synthetic and public datasets are performed to examine the performance of the proposed method. The results show that both the initial states and the spatial-temporal parameters can be well estimated. The method outperforms other contemporary methods used for comparison.

scholarly journals Rotation Estimation: A Closed-Form Solution Using Spherical Moments

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4958
Author(s):  
Hicham Hadj-Abdelkader ◽  
Omar Tahri ◽  
Houssem-Eddine Benseddik
Keyword(s):  
Image Processing ◽  
Closed Form ◽  
Synthetic Data ◽  
Closed Form Solution ◽  
Form Solution ◽  
Unified Model ◽  
Experimental Results ◽  
Motion Information ◽  
Vision Sensors ◽  
Spherical Projection

Photometric moments are global descriptors of an image that can be used to recover motion information. This paper uses spherical photometric moments for a closed form estimation of 3D rotations from images. Since the used descriptors are global and not of the geometrical kind, they allow to avoid image processing as features extraction, matching, and tracking. The proposed scheme based on spherical projection can be used for the different vision sensors obeying the central unified model: conventional, fisheye, and catadioptric. Experimental results using both synthetic data and real images in different scenarios are provided to show the efficiency of the proposed method.

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