Fisheye Lens Distortion Calibration Based on the Lens Charactetic Curves

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.

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Evaluating the Impact of Wide-Angle Lens Distortion on Learning-based Depth Estimation

10.1109/cvprw53098.2021.00409 ◽

2021 ◽

Author(s):

Julie Buquet ◽

Jinsong Zhang ◽

Patrice Roulet ◽

Simon Thibault ◽

Jean-Francois Lalonde

Keyword(s):

Depth Estimation ◽

Lens Distortion ◽

Wide Angle ◽

Wide Angle Lens ◽

The Impact

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CALIBRATION OF SMARTPHONE’S REAR DUAL CAMERA SYSTEM

Geodesy and Cartography ◽

10.3846/gac.2021.13434 ◽

2021 ◽

Vol 47 (4) ◽

pp. 162-169

Author(s):

Mohammed Aldelgawy ◽

Isam Abu-Qasmieh

Keyword(s):

Lens Distortion ◽

Stereo Pair ◽

Calibration Model ◽

Wide Angle ◽

Camera System ◽

Check Points ◽

Extrinsic Parameters ◽

Wide Angle Lens ◽

Chessboard Pattern ◽

Distortion Parameters

This paper aims to calibrate smartphone’s rear dual camera system which is composed of two lenses, namely; wide-angle lens and telephoto lens. The proposed approach handles large sized images. Calibration was done by capturing 13 photos for a chessboard pattern from different exposure positions. First, photos were captured in dual camera mode. Then, for both wide-angle and telephoto lenses, image coordinates for node points of the chessboard were extracted. Afterwards, intrinsic, extrinsic, and lens distortion parameters for each lens were calculated. In order to enhance the accuracy of the calibration model, a constrained least-squares solution was applied. The applied constraint was that the relative extrinsic parameters of both wide-angle and telephoto lenses were set as constant regardless of the exposure position. Moreover, photos were rectified in order to eliminate the effect of lens distortion. For results evaluation, two oriented photos were chosen to perform a stereo-pair intersection. Then, the node points of the chessboard pattern were used as check points.

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An efficient correction method of wide-angle lens distortion for surveillance systems

2009 IEEE International Symposium on Circuits and Systems ◽

10.1109/iscas.2009.5118485 ◽

2009 ◽

Cited By ~ 2

Author(s):

Wonjun Kim ◽

Changick Kim

Keyword(s):

Correction Method ◽

Lens Distortion ◽

Surveillance Systems ◽

Wide Angle ◽

Wide Angle Lens

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Wide Angle Lens for Electro-Optical System

Journal of Optics ◽

10.1007/bf03549188 ◽

1988 ◽

Vol 17 (4) ◽

pp. 101-103

Author(s):

P. N. Ageswara Rao ◽

K. K. Banerjee ◽

H. S. Singh

Keyword(s):

Optical System ◽

Wide Angle ◽

Wide Angle Lens

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ROBOT VISION: CALIBRATION OF WIDE-ANGLE LENS CAMERAS USING COLLINEARITY CONDITION AND K-NEAREST NEIGHBOUR REGRESSION

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-1-93-2018 ◽

2018 ◽

Vol XLII-1 ◽

pp. 93-99 ◽

Cited By ~ 2

Author(s):

J. C. K. Chow ◽

I. Detchev ◽

K. D. Ang ◽

K. Morin ◽

K. Mahadevan ◽

...

Keyword(s):

Robot Vision ◽

Calibration Method ◽

Bundle Adjustment ◽

Conventional Approach ◽

Wide Angle ◽

Nearest Neighbour ◽

Camera System ◽

Comparison Results ◽

Wide Angle Lens ◽

Normal Angle

Abstract. Visual perception is regularly used by humans and robots for navigation. By either implicitly or explicitly mapping the environment, ego-motion can be determined and a path of actions can be planned. The process of mapping and navigation are delicately intertwined; therefore, improving one can often lead to an improvement of the other. Both processes are sensitive to the interior orientation parameters of the camera system and mathematically modelling these systematic errors can often improve the precision and accuracy of the overall solution. This paper presents an automatic camera calibration method suitable for any lens, without having prior knowledge about the sensor. Statistical inference is performed to map the environment and localize the camera simultaneously. K-nearest neighbour regression is used to model the geometric distortions of the images. A normal-angle lens Nikon camera and wide-angle lens GoPro camera were calibrated using the proposed method, as well as the conventional bundle adjustment with self-calibration method (for comparison). Results showed that the mapping error was reduced from an average of 14.9mm to 1.2mm (i.e. a 92% improvement) and 66.6mm to 1.5mm (i.e. a 98% improvement) using the proposed method for the Nikon and GoPro cameras, respectively. In contrast, the conventional approach achieved an average 3D error of 0.9mm (i.e. 94% improvement) and 6mm (i.e. 91% improvement) for the Nikon and GoPro cameras, respectively. Thus, the proposed method performs more consistently, irrespective of the lens/sensor used: it yields results that are comparable to the conventional approach for normal-angle lens cameras, and it has the additional benefit of improving calibration results for wide-angle lens cameras.

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