scholarly journals Holographic Micromirror Array with Diffuse Areas for Accurate Calibration of 3D Light-Field Display

2020 ◽  
Vol 10 (20) ◽  
pp. 7188
Author(s):  
Lode Jorissen ◽  
Ryutaro Oi ◽  
Koki Wakunami ◽  
Yasuyuki Ichihashi ◽  
Gauthier Lafruit ◽  
...  
Keyword(s):  
Light Field ◽  
3D Visualization ◽  
Calibration Method ◽  
Automatic Calibration ◽  
Display System ◽  
Extrinsic Parameters ◽  
Calibration Algorithm ◽  
Fully Automatic ◽  
Intrinsic And Extrinsic Parameters ◽  
Micromirror Array

Light field 3D displays require a precise alignment between the display source and the micromirror-array screen for error free 3D visualization. Hence, calibrating the system using an external camera becomes necessary, before displaying any 3D contents. The inter-dependency of the intrinsic and extrinsic parameters of display-source, calibration-camera, and micromirror-array screen, makes the calibration process very complex and error-prone. Thus, several assumptions are made with regard to the display setup, in order to simplify the calibration. A fully automatic calibration method based on several such assumptions was reported by us earlier. Here, in this paper, we report a method that uses no such assumptions, but yields a better calibration. The proposed method adapts an optical solution where the micromirror-array screen is fabricated as a computer generated hologram with a tiny diffuser engraved at one corner of each elemental micromirror in the array. The calibration algorithm uses these diffusing areas as markers to determine the relation between the pixels of display source and the mirrors in the micromirror-array screen. Calibration results show that virtually reconstructed 3D scenes align well with the real world contents, and are free from any distortion. This method also eliminates the position dependency of display source, calibration-camera, and mirror-array screen during calibration, which enables easy setup of the display system.

scholarly journals A Novel Calibration Algorithm for Cable-Driven Parallel Robots with Application to Rehabilitation

2019 ◽  
Vol 9 (11) ◽  
pp. 2182 ◽  
Author(s):  
Han Yuan ◽  
Xianghui You ◽  
Yongqing Zhang ◽  
Wenjing Zhang ◽  
Wenfu Xu
Keyword(s):  
Calibration Method ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Human Robot Interaction ◽  
Automatic Calibration ◽  
Unknown Parameters ◽  
Robot Interaction ◽  
Geometric Calibration ◽  
Rehabilitation Robots ◽  
Calibration Algorithm

Cable-driven parallel robots are suitable candidates for rehabilitation due to their intrinsic flexibility and adaptability, especially considering the safety of human–robot interaction. However, there are still some challenges to apply cable-driven parallel robots to rehabilitation, one of which is the geometric calibration. This paper proposes a new automatic calibration method that is applicable for cable-driven parallel rehabilitation robots. The key point of this method is to establish the mapping between the unknown parameters to be calibrated and the parameters that could be measured by the inner sensors and then use least squares algorithm to find the solutions. Specifically, the unknown parameters herein are the coordinates of the attachment points, and the measured parameters are the lengths of the redundant cables. Simulations are performed on a 3-DOF parallel robot driven by four cables for validation. Results show that the proposed calibration method could precisely find the real coordinate values of the attachment points, with errors less than 10 − 12 mm. Trajectory simulations also indicate that the positioning accuracy of the cable-driven parallel robot (CDPR) could be greatly improved after calibration using the proposed method.

A Camera Calibration Method Based on Plane Grid Points

2011 ◽  
Vol 230-232 ◽  
pp. 723-727 ◽  
Author(s):  
Bao Feng Zhang ◽  
Xiu Zhen Tian ◽  
Xiao Ling Zhang
Keyword(s):  
Camera Calibration ◽  
Model Calibration ◽  
Calibration Method ◽  
Translation Vector ◽  
Plane Model ◽  
Extrinsic Parameters ◽  
Computer Vision Systems ◽  
Grid Points ◽  
Intrinsic And Extrinsic Parameters ◽  
Plane Grid

In order to simplify previous camera calibration method, this paper put forward an easy camera calibration method based on plane grid points on the foundation of Heikkila plane model calibration method. Intrinsic and extrinsic parameters of the camera are calibrated with MATLAB, then the rotation matrix and the translation vector are calculated. The experiment results show this method is not only simple in practice, but also can meet the needs of computer vision systems.

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.

A vision-based fully-automatic calibration method for hand-eye serial robot

2015 ◽  
Vol 42 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Haixia Wang ◽  
Xiao Lu ◽  
Zhanyi Hu ◽  
Yuxia Li
Keyword(s):  
Design Methodology ◽  
Calibration Method ◽  
Automatic Calibration ◽  
Screw Axis ◽  
Robot System ◽  
Camera System ◽  
Content Type ◽  
Serial Robot ◽  
Fully Automatic ◽  
Robot Body

Purpose – The purpose of this paper is to present a fully automatic calibration method for hand-eye serial robot system is presented in this paper. The so-called “fully automatic” is meant to calibrate the robot body, the hand-eye relation, and the used measuring binocular system at the same time. Design/methodology/approach – The calibration is done by controlling the joints to rotate several times one by one in the reverse order (i.e. from the last one to the first one), and simultaneously take pictures of the checkerboard patterns by the stereo camera system attached on the end-effector, then the whole robot system can be calibrated automatically from these captured images. In addition, a nonlinear optimization step is used to further refine the calibration results. Findings – The proposed method is essentially based on an improved screw axis identification method, and it needs only a mirror and some paper checkerboard patterns without resorting to any additional costly measuring instrument. Originality/value – Simulations and real experiments on MOTOMAN-UP6 robot system demonstrate the feasibility and effectiveness of the proposed method.

A Novel Camera Calibration Method Based on Simulated Annealing Genetic Algorithm

2015 ◽  
Vol 719-720 ◽  
pp. 1184-1190
Author(s):  
Shuang Ran ◽  
Long Ye ◽  
Jing Ling Wang ◽  
Qin Zhang
Keyword(s):  
Genetic Algorithm ◽  
Simulated Annealing ◽  
Camera Calibration ◽  
Simulated Annealing Algorithm ◽  
Image Plane ◽  
Calibration Method ◽  
Simulated Annealing Genetic Algorithm ◽  
Extrinsic Parameters ◽  
Annealing Algorithm ◽  
Intrinsic And Extrinsic Parameters

The optimization of the camera’s intrinsic and extrinsic parameters is a key step after obtaining the initialized parameters’ state by considering the homography between the board space plane and the image plane in Zhengyou Zhang method. In this paper, we proposed a camera calibration optimization algorithm by adopting genetic algorithm and the simulated annealing algorithm. The experiment results demonstrate that our algorithm can improve the precision of the camera calibration to a certain extent.

A Rapid Auto-Caliberation Method in Projector-Camera System

2011 ◽  
Vol 58-60 ◽  
pp. 2308-2313
Author(s):  
Tao Yang ◽  
Yue Liu ◽  
You Lu
Keyword(s):  
Large Scale ◽  
Calibration Method ◽  
Interactive System ◽  
Automatic Calibration ◽  
Camera System ◽  
Projected Image ◽  
Error Elimination ◽  
Fully Automatic ◽  
Automatic Error ◽  
Automatic Elimination

A precise, fast, and fully automatic calibration method is proposed to address the shortcomings in currently used large-scale interactive camera-projector systems. These shortcomings include a small number of calibration points used in manual calibration, large errors, huge time consumption, and lack of professional quality operations. The proposed method applies mechanical wavelength switching in the projected image to capture multi-regional vertices. The co-linearity of each point in the projected images is calculated to determine the actual location of the interactive points in the projected image. The point-by-point computation adopted in the method promotes the automatic elimination of uncorrectable systematic errors in large-scale optical devices. The automatic error elimination not only increases the accuracy of the interactive system and reduces the complexity of system installation, but also increases the flexibility of the interactive system.

scholarly journals Common self-polar triangle of separate circles for light field camera calibration

2021 ◽  
Vol 39 (3) ◽  
pp. 521-528
Author(s):  
Qi Zhang ◽  
Qing Wang
Keyword(s):  
Camera Calibration ◽  
Light Field ◽  
Linear Optimization ◽  
Real Data ◽  
Calibration Method ◽  
Calibration Algorithm ◽  
Calibration Pattern ◽  
The Common ◽  
Projection Center ◽  
Planar Homography

Due to the trade-off between spatial resolution and angular resolution of the light field, it is difficult to extract high precision corner points and line features from light fields for calibration. A novel calibration pattern of separate circles is designed, and a light field camera calibration method based on common self-polar triangle with respect to separate circles is proposed in this paper. First, we explore the uniquity and reconstruction of common self-polar triangle with respect to sperate circles. Then, based on projections of the multi-projection-center model on the plane and conic, the common self-polar triangle on the sub-aperture image is reconstructed and used to estimate planar homography. Finally, a light field camera calibration algorithm is then proposed, including linear initialization and non-linear optimization. Experimental results on both synthetic and real data have verified the effectiveness and robustness of the method and algorithm proposed.

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.

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