A fast underwater calibration method based on vanishing point optimization of two orthogonal parallel lines

Sun, Jin; Wang, Heping; Zhu, Xijing

doi:10.1016/j.measurement.2021.109305

Cited by 13 publications

(4 citation statements)

References 25 publications

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“…These straight lines were used to estimate the vanishing points. The vanishing‐point constraint was established based on the relation between the vanishing points and IOPs and EOPs of Navcam (Caprile and Torre, 1990; Grammatikopoulos et al., 2007; Sun et al., 2021). The mathematical model of the vanishing‐point constraint is given by the following equations, which describe the relationships between the vanishing points, IOPs and EOPs:

({, \begin{array}{l} x_{X_{\infty}} goodbreak= f \cot φ \sec ω \cos κ goodbreak- f \tan ω \sin κ \\ y_{X_{\infty}} goodbreak= goodbreak- f \cot φ \sec ω \sin κ goodbreak- f \tan ω \cos κ \\ x_{Y_{\infty}} goodbreak= f \cot ω \sin κ \\ y_{Y_{\infty}} goodbreak= f \cot ω \cos κ \\ x_{Z_{\infty}} goodbreak= goodbreak- f \tan φ \sec ω \cos κ goodbreak- f \tan ω \sin κ \\ y_{Z_{\infty}} goodbreak= f \tan φ \sec ω \sin κ goodbreak- f \tan ω \cos κ, \end{array})

…”

Section: Methodsmentioning

confidence: 99%

“…These straight lines were used to estimate the vanishing points. The vanishing-point constraint was established based on the relation between the vanishing points and IOPs and EOPs of Navcam (Caprile and Torre, 1990;Grammatikopoulos et al, 2007;Sun et al, 2021). The mathematical model of the vanishing-point constraint is given by the following equations, which describe the relationships between the vanishing points, IOPs and EOPs:…”

Section: In-orbit Calibrationmentioning

confidence: 99%

See 1 more Smart Citation

Positioning Accuracy of the Zhurong Mars Rover's Hand–Eye System

Zhang

Peng

et al. 2022

The Photogrammetric Record

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The hand-eye system is an important component of the Zhurong rover, which is crucial for positioning, terrain reconstruction, stereo vision measurement and mission planning functions. The hand-eye system consists of a navigation camera and mast mechanism, and its positioning accuracy has an important effect on the teleoperation mission of the Zhurong rover. A positioning method that combines close-range photogrammetry and robot kinematics is proposed. It includes geometric calibration, stereo vision measurement and coordinate transformations. Experiments were carried out in different scenes (for example, field, laboratory and Ó 2022 Remote Sensing and Photogrammetry Society and John Wiley & Sons Ltd.Mars) to verify the positioning accuracy of the hand-eye system. The minimum and maximum positioning errors of the hand-eye system, as verified by in-orbit checkpoints, were 16.5 and 28.7 mm, respectively. This positioning accuracy can effectively satisfy the requirements of the teleoperation mission of the Zhurong rover.

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({, \begin{array}{l} x_{X_{\infty}} goodbreak= f \cot φ \sec ω \cos κ goodbreak- f \tan ω \sin κ \\ y_{X_{\infty}} goodbreak= goodbreak- f \cot φ \sec ω \sin κ goodbreak- f \tan ω \cos κ \\ x_{Y_{\infty}} goodbreak= f \cot ω \sin κ \\ y_{Y_{\infty}} goodbreak= f \cot ω \cos κ \\ x_{Z_{\infty}} goodbreak= goodbreak- f \tan φ \sec ω \cos κ goodbreak- f \tan ω \sin κ \\ y_{Z_{\infty}} goodbreak= f \tan φ \sec ω \sin κ goodbreak- f \tan ω \cos κ, \end{array})

…”

Section: Methodsmentioning

confidence: 99%

Section: In-orbit Calibrationmentioning

confidence: 99%

Positioning Accuracy of the Zhurong Mars Rover's Hand–Eye System

Zhang

Peng

et al. 2022

The Photogrammetric Record

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show abstract

“…Li [20] equivalently treats the underwater camera model as a pinhole model with changes in focal length, and provides the corresponding process for calculating camera parameters. Sun [21] proposed a rapid underwater calibration method based on two sets of mutually orthogonal parallel lines, optimizing the vanishing point to determine its focal length, which is based on an air-water equivalent focal length model. Bashar [22] proposed the theory of refraction invariance, dividing the calculation of imaging parameters into refractive and non-refractive related sets, and utilizing an approximate linear model to compute camera parameters.…”

Section: Introductionmentioning

confidence: 99%

Underwater Camera Calibration Based on Double Refraction

Sun,

Zhou,

Zhang

et al. 2024

JMSE

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Underwater camera calibration plays a pivotal role in underwater positioning and underwater mapping reconstruction, making it crucial for achieving precise spatial measurements in underwater environments. To elevate measurement accuracy, we have refined the calibration methodology for underwater cameras. Firstly, we conducted an in-depth investigation into the intricate challenges posed by double refraction errors arising from light passing through water–glass–air interfaces. To address this issue, we established a double refraction model based on the actual underwater light paths, laying the groundwork for our calibration efforts. Furthermore, to tackle the problem of determining multiple camera parameters, we proposed a parameter optimization method based on genetic algorithms, capable of navigating the complex parameter space. Finally, compared with other algorithms, our method enables more precise determination of underwater camera parameters.

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“…Theoretically, with the geometrical location of the measurement area and optical parameters of the LF camera, the weight coefficient can be calculated through a direct ray tracing method [18], i.e., tracing the light rays from the target voxel to the image sensor. However, in practical experiments, the ray tracing from the target voxels is hampered by the light ray deflections in the object space, which is caused by the refractive index changes [19,20]. Considering that the light ray from the tracer particles passes through the flow, optical window and air, refractions must exist at the interfaces.…”

Section: Introductionmentioning

confidence: 99%