scholarly journals On the issue of camera calibration with narrow angular field of view

2009 ◽  
Author(s):  
Klaus H. Strobl ◽  
Wolfgang Sepp ◽  
Gerd Hirzinger
Keyword(s):  
Camera Calibration ◽  
Field Of View ◽  
Angular Field Of View

scholarly journals Extrinsic Camera Calibration with Line-Laser Projection

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1091
Author(s):  
Izaak Van Crombrugge ◽  
Rudi Penne ◽  
Steve Vanlanduit
Keyword(s):  
Camera Calibration ◽  
Real World ◽  
Large Scale ◽  
State Of The Art ◽  
Bundle Adjustment ◽  
Field Of View ◽  
Extrinsic Calibration ◽  
Practical Procedure ◽  
Partial Overlap

Knowledge of precise camera poses is vital for multi-camera setups. Camera intrinsics can be obtained for each camera separately in lab conditions. For fixed multi-camera setups, the extrinsic calibration can only be done in situ. Usually, some markers are used, like checkerboards, requiring some level of overlap between cameras. In this work, we propose a method for cases with little or no overlap. Laser lines are projected on a plane (e.g., floor or wall) using a laser line projector. The pose of the plane and cameras is then optimized using bundle adjustment to match the lines seen by the cameras. To find the extrinsic calibration, only a partial overlap between the laser lines and the field of view of the cameras is needed. Real-world experiments were conducted both with and without overlapping fields of view, resulting in rotation errors below 0.5°. We show that the accuracy is comparable to other state-of-the-art methods while offering a more practical procedure. The method can also be used in large-scale applications and can be fully automated.

scholarly journals Calibration of the Relative Orientation between Multiple Depth Cameras Based on a Three-Dimensional Target

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3008 ◽  
Author(s):  
Zhe Liu ◽  
Zhaozong Meng ◽  
Nan Gao ◽  
Zonghua Zhang
Keyword(s):  
Coordinate System ◽  
Camera Calibration ◽  
Three Dimensional ◽  
Field Of View ◽  
Depth Information ◽  
Depth Camera ◽  
Depth Cameras ◽  
Calibration Methods ◽  
3D Shape Reconstruction ◽  
Single Coordinate

Depth cameras play a vital role in three-dimensional (3D) shape reconstruction, machine vision, augmented/virtual reality and other visual information-related fields. However, a single depth camera cannot obtain complete information about an object by itself due to the limitation of the camera’s field of view. Multiple depth cameras can solve this problem by acquiring depth information from different viewpoints. In order to do so, they need to be calibrated to be able to accurately obtain the complete 3D information. However, traditional chessboard-based planar targets are not well suited for calibrating the relative orientations between multiple depth cameras, because the coordinates of different depth cameras need to be unified into a single coordinate system, and the multiple camera systems with a specific angle have a very small overlapping field of view. In this paper, we propose a 3D target-based multiple depth camera calibration method. Each plane of the 3D target is used to calibrate an independent depth camera. All planes of the 3D target are unified into a single coordinate system, which means the feature points on the calibration plane are also in one unified coordinate system. Using this 3D target, multiple depth cameras can be calibrated simultaneously. In this paper, a method of precise calibration using lidar is proposed. This method is not only applicable to the 3D target designed for the purposes of this paper, but it can also be applied to all 3D calibration objects consisting of planar chessboards. This method can significantly reduce the calibration error compared with traditional camera calibration methods. In addition, in order to reduce the influence of the infrared transmitter of the depth camera and improve its calibration accuracy, the calibration process of the depth camera is optimized. A series of calibration experiments were carried out, and the experimental results demonstrated the reliability and effectiveness of the proposed method.

scholarly journals On the Problem of Standard Fields for CCD Astrometry

1995 ◽  
Vol 167 ◽  
pp. 353-354
Author(s):  
I. S. Guseva
Keyword(s):  
Focal Length ◽  
Field Of View ◽  
Proper Motions ◽  
Angular Scale ◽  
Ccd Observations ◽  
Photometric Measurements ◽  
Angular Field Of View

At the start of CCD observations one must investigate the metrological properties of the complex instrument: optics + CCD. One needs a densely spaced set of stars with precise coordinates and magnitudes. We first used the Pleiades catalogue by Eichhorn et al. (1970). Experimental observations were started at Pulkovo in 1993 using a very small refractor (D = 100 mm, F = 712 mm) equipped with a CCD ISD015A (520 × 580 pixels, 18 × 24 microns). The focal length of our astrograph provides an angular field of view of 45 × 67 arcmin (angular scale is 5.2 × 7 arcsec/pixel). With different exposures we can observe all stars with magnitudes from 2 to 16. The first observations were made to evaluate the accuracy of our positional and photometric measurements. Unfortunately, it appears that the catalogue of the Pleiades by Eichhorn is not good enough for this purpose because its epoch is very far from that of our observations and proper motions were not provided for the majority of the stars. The internal precision of our measurements (0.1–0.3 arcsec) allows us to determine the corrections to the stellar positions by Eichhorn et al. (1970)

Effect of field of view on the accuracy of camera calibration

Optik ◽  
2014 ◽  
Vol 125 (2) ◽  
pp. 844-849 ◽  
Author(s):  
Xieliu Yang ◽  
Suping Fang
Keyword(s):  
Camera Calibration ◽  
Field Of View

The Method of Real-Time Distance Measurement Based on Monocular Vision

2011 ◽  
Vol 403-408 ◽  
pp. 1451-1454 ◽  
Author(s):  
Wei Lu ◽  
Ting Ting Wang ◽  
Jing Hui Chu
Keyword(s):  
Computational Complexity ◽  
Real Time ◽  
Camera Calibration ◽  
Pitch Angle ◽  
Monocular Vision ◽  
Field Of View ◽  
Target Point ◽  
Robot Tracking ◽  
Time Distance ◽  
Common Deficiency

The paper proposes a real-time monocular vision-based algorithm that can be applied to robot tracking. Unlike the models used in other papers, the model used in this paper is suitable for the condition that the camera is looking up. There is a common deficiency existing in previous models that the target point is constrained to some areas of the camera field. To overcome the shortcomings, the camera field of view is divided into three regions which also reduces the computational complexity. The intrinsic parameters of camera can be obtained by calibration. Pitch angle rectification, together with camera calibration, improves the ranging accuracy.

scholarly journals IMPROVEMENT OF THE METHOD OF MEASURING ANGULAR FIELD OF VISION OF AN OPTICAL SIGHT

2020 ◽  
Vol 6 (1) ◽  
pp. 181-188
Author(s):  
Maxim E. Kobzar ◽  
Aelita V. Shaburova
Keyword(s):  
Field Of View ◽  
Measuring Instrument ◽  
Practical Application ◽  
Instrument Making ◽  
Field Of Vision ◽  
Quality Of Products ◽  
The Moment ◽  
Site Training ◽  
Angular Field Of View

The article discusses the practical application of the method of measuring the angular field of view of an optical sight using theodolite. «Novosibirsk Instrument-Making Plant» is one of the largest manufacturers of shooting and observation optics throughout Russia. To improve the quality of products manufactured at the plant (optical and hunting sights, binoculars, telescopes, monoculars, etc.), it is necessary to verify the main technical characteristics during their production using an approved type measuring instrument. At the moment, the measurement of the angular field of view at the enterprise of JSC "NPZ" is carried out at a specialized site (training ground). This technique will allow testing on-site. The article describes an experiment in the course of which the results were obtained, according to which it can be concluded that this technique is suitable for measuring the angular field of view.

scholarly journals DEVELOPMENT OF THE METHOD OF PERFORMANCE OF MEASUREMENTS OF ANGULAR FIELD OF VIEW OF OPTICAL PRODUCTS

2019 ◽  
Vol 6 (1) ◽  
pp. 227-230
Author(s):  
Maxim Kobzar ◽  
Valery Pavlenko
Keyword(s):  
Field Of View ◽  
Measuring Instruments ◽  
Angular Field Of View

The article deals with the problem of the lack of a technique for measuring the angular field of view of optical products, using approved-type measuring instruments.

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