Calibration of Camera with Rational Function Lens Distortion Model

Junhui, 黄军辉 Huang; Zhao, 王昭 Wang; Qi, 薛琦 Xue; Jianmin, 高建民 Gao

doi:10.3788/cjl201441.0508001

Cited by 3 publications

(1 citation statement)

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“…For zoom lenses, the change of focal length will result in changes in the center of the distortion, and different focal lengths correspond to different nonlinear distortions [11]. Adopting the general camera calibration methods, like [12] a two-step method based on radial constraint by Tsai [12], Zhang's calibration method focusing on the plane target [13] and the camera calibration approach based on the rational functional lens dist ortion model [14] is difficult to achieve camera online real-time correction.…”

Section: Distortion Correction Methods Of a Zoom Lens Based On The Va...mentioning

confidence: 99%

Distortion correction method of a zoom lens based on the vanishing point geometric constraint

Zhu

Liu

Xin-yun

et al. 2019

Meas. Sci. Technol.

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In order to solve the problem that the distortion parameter of the zoom lens varies with focal length changes, a correction method for a zoom lens based on the minimum fitting error of a vanishing point geometric constraint is proposed. In light of a calibrated image with parallel line clusters without knowing the metric, the method can quickly correct the distortion of zoom lens in full focal length by the regression fitting of parameters. Firstly, based on the radial distortion division model, the functional relationship between the vanishing point and the radial distortion coefficient is established according to the geometric constraint of the vanishing point, and the first-order radial distortion coefficient of the camera is estimated by the Levenberg–Marquardt algorithm. And then, in terms of the principle of the deviation error minimization, the least squares can be used to fit the equation of straight line of the corrected points to optimize the center-of-distortion. Finally, the variation of distortion parameters with focal length is analyzed, the distortion parameter corresponding table between distortion parameters and focal length and the empirical formula of fitting are established. The results show that the root mean square error corrected by the fitting empirical formulas and the least squares support vector regression parameter corresponding table method for three different focal lengths are 1.16 pixels and 0.83 pixels, respectively. Moreover, those two ways are about 13% and 19% faster than Zhang’s method, respectively. By mapping this method to FPGA, the application effect of photographic UAV, security monitoring and other equipment requiring rapid response can be greatly improved.

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Section: Distortion Correction Methods Of a Zoom Lens Based On The Va...mentioning

confidence: 99%

Distortion correction method of a zoom lens based on the vanishing point geometric constraint

Zhu

Liu

Xin-yun

et al. 2019

Meas. Sci. Technol.

View full text Add to dashboard Cite

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Distortion Correction Method of Zoom Lens Based on Vanishing Point Geometric Constraint

Zhu

Liu

Wang

et al. 2019

Cognitive Internet of Things: Frameworks, Tools and Applications

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DoF-Dependent and Equal-Partition Based Lens Distortion Modeling and Calibration Method for Close-Range Photogrammetry

Yuan

et al. 2020

Sensors

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Lens distortion is closely related to the spatial position of depth of field (DoF), especially in close-range photography. The accurate characterization and precise calibration of DoF-dependent distortion are very important to improve the accuracy of close-range vision measurements. In this paper, to meet the need of short-distance and small-focal-length photography, a DoF-dependent and equal-partition based lens distortion modeling and calibration method is proposed. Firstly, considering the direction along the optical axis, a DoF-dependent yet focusing-state-independent distortion model is proposed. By this method, manual adjustment of the focus and zoom rings is avoided, thus eliminating human errors. Secondly, considering the direction perpendicular to the optical axis, to solve the problem of insufficient distortion representations caused by using only one set of coefficients, a 2D-to-3D equal-increment partitioning method for lens distortion is proposed. Accurate characterization of DoF-dependent distortion is thus realized by fusing the distortion partitioning method and the DoF distortion model. Lastly, a calibration control field is designed. After extracting line segments within a partition, the de-coupling calibration of distortion parameters and other camera model parameters is realized. Experiment results shows that the maximum/average projection and angular reconstruction errors of equal-increment partition based DoF distortion model are 0.11 pixels/0.05 pixels and 0.013°/0.011°, respectively. This demonstrates the validity of the lens distortion model and calibration method proposed in this paper.

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Calibration of Camera with Rational Function Lens Distortion Model

Cited by 3 publications

References 0 publications

Distortion correction method of a zoom lens based on the vanishing point geometric constraint

Distortion correction method of a zoom lens based on the vanishing point geometric constraint

Distortion Correction Method of Zoom Lens Based on Vanishing Point Geometric Constraint

DoF-Dependent and Equal-Partition Based Lens Distortion Modeling and Calibration Method for Close-Range Photogrammetry

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