scholarly journals Correction of Barrel Distortion in Fisheye Lens Images Using Image-Based Estimation of Distortion Parameters

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 45723-45733 ◽  
Author(s):  
Minjung Lee ◽  
Hyungtae Kim ◽  
Joonki Paik
Keyword(s):  
Fisheye Lens ◽  
Distortion Parameters ◽  
Barrel Distortion

Fisheye Lens Distortion Calibration Based on the Lens Charactetic Curves

2014 ◽  
Vol 519-520 ◽  
pp. 636-639
Author(s):  
Bao Long Zhang ◽  
Shao Jing Zhang ◽  
Wei Qi Ding ◽  
Hui Shuang Shi
Keyword(s):  
Optical System ◽  
Characteristic Curve ◽  
Calibration Method ◽  
Lens Distortion ◽  
Wide Angle ◽  
Forming Process ◽  
Fisheye Lens ◽  
Large Scope ◽  
Wide Angle Lens ◽  
Barrel Distortion

The fisheye lens is a kind of ultra wide angle lens, which can produce a big super-wide-angle lens distortion. In order to cover a large scope of light, barrel distortion is artificially added to the optical system. However, in some cases this distortion is not allowed, then it requires calibrations of those distortions. Most of the traditional distortion calibration method uses target plane calibration to do it. This paper discusses the way of design fisheye lens, through which we can know the forming process of distortion clearly. Based on this paper, a simple and effective calibration method can be understood. Different from common camera calibration method, the proposed calibration method can avoid the error occurring in the process of calibrating test, that directly use the lens’ characteristic curve. Through multiple sets of experimental verifications, this method is effective and feasible.

Camera Calibration Method Based on Circle Plane Board

2013 ◽  
Vol 475-476 ◽  
pp. 184-187
Author(s):  
Wen Guo Li ◽  
Shao Jun Duan
Keyword(s):  
Camera Calibration ◽  
Calibration Method ◽  
Lens Distortion ◽  
Edge Extraction ◽  
Circle Plane ◽  
Circle Centre ◽  
Extraction Algorithm ◽  
Calibration Algorithm ◽  
Characteristic Points ◽  
Distortion Parameters

We present a camera calibration method based on circle plane board. The centres of circles on plane are regarded as the characteristic points, which are used to implement camera calibration. The proposed calibration is more accurate than many previous calibration algorithm because of the merit of the coordinate of circle centre being obtained from thousand of of edge pionts of ellipse, which is very reliable to image noise caused by edge extraction algorithm. Experiments shows the proposed algorithm can obtain high precise inner parameters, and lens distortion parameters.

Fisheye lens camera based surveillance system for wide field of view monitoring

Optik ◽  
2016 ◽  
Vol 127 (14) ◽  
pp. 5636-5646 ◽  
Author(s):  
Hyungtae Kim ◽  
Jaehoon Jung ◽  
Joonki Paik
Keyword(s):  
Surveillance System ◽  
Field Of View ◽  
Wide Field ◽  
Fisheye Lens ◽  
Wide Field Of View

A hybrid regularization scheme for the inversion of magnetotelluric data from natural and controlled sources to layer and distortion parameters

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. E301-E315 ◽  
Author(s):  
Thomas Kalscheuer ◽  
Juliane Hübert ◽  
Alexey Kuvshinov ◽  
Tobias Lochbühler ◽  
Laust B. Pedersen
Keyword(s):  
Transfer Functions ◽  
Homogeneous Distribution ◽  
Stable Configuration ◽  
Inversion Algorithm ◽  
Magnetotelluric Data ◽  
Data Set ◽  
Near Surface ◽  
Minimum Solution ◽  
Magnetic Transfer ◽  
Distortion Parameters

Magnetotelluric (MT), radiomagnetotelluric (RMT), and, in particular, controlled-source audiomagnetotelluric (CSAMT) data are often heavily distorted by near-surface inhomogeneities. We developed a novel scheme to invert MT, RMT, and CSAMT data in the form of scalar or tensorial impedances and vertical magnetic transfer functions simultaneously for layer resistivities and electric and magnetic galvanic distortion parameters. The inversion scheme uses smoothness constraints to regularize layer resistivities and either Marquardt-Levenberg damping or the minimum-solution length criterion to regularize distortion parameters. A depth of investigation range is estimated by comparing layered model sections derived from first- and second-order smoothness constraints. Synthetic examples demonstrate that earth models are reconstructed properly for distorted and undistorted tensorial CSAMT data. In the inversion of scalar CSAMT data, such as the determinant impedance or individual tensor elements, the reduced number of transfer functions inevitably leads to increased ambiguity for distortion parameters. As a consequence of this ambiguity for scalar data, distortion parameters often grow over the iterations to unrealistic absolute values when regularized with the Marquardt-Levenberg scheme. Essentially, compensating relationships between terms containing electric and/or magnetic distortion are used in this growth. In a regularization with the minimum solution length criterion, the distortion parameters converge into a stable configuration after several iterations and attain reasonable values. The inversion algorithm was applied to a CSAMT field data set collected along a profile over a tunnel construction site at Hallandsåsen, Sweden. To avoid erroneous inverse models from strong anthropogenic effects on the data, two scalar transfer functions (one scalar impedance and one scalar vertical magnetic transfer function) were selected for inversion. Compared with a regularization of distortion parameters with the Marquardt-Levenberg method, the minimum-solution length criterion yielded smaller absolute values of distortion parameters and a horizontally more homogeneous distribution of electrical conductivity.

Optical system design of dual band CCTV fisheye lens

2021 ◽  
Vol 42 (0) ◽  
pp. 1-5
Author(s):  
ZHANG Xin-ting ◽  
◽  
◽  
KANG Lei ◽  
WU Qian-qian ◽  
...  
Keyword(s):  
System Design ◽  
Optical System ◽  
Dual Band ◽  
Optical System Design ◽  
Fisheye Lens
Sign in / Sign up

Export Citation Format

Share Document