An improved projector calibration method for structured-light 3D measurement systems

Yu, Jae Sik; Zhang, Yaqin; Cai, Zewei; Tang, Qijian; Liu, Xiaoli; Xi, Jiangtao; Peng, Xiang

doi:10.1088/1361-6501/abe447

Cited by 10 publications

(2 citation statements)

References 31 publications

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“…Although commercial projectors generally have gamma nonlinear preset values to better adapt to human visual perception, projector nonlinear errors can be well handled through calibration or post-processing compensation methods [23]. Distortions of camera and projector lenses can also be corrected and compensated through calibration [35,36]. In contrast, intensity noise and motion artifacts are random errors that cannot be easily controlled.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of variant shifting-phase coding method based on noise error model

Wu,

Mu,

Cheng

et al. 2024

Meas. Sci. Technol.

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Phase shifting algorithm, which is well-known for its high-accuracy and high-resolution, plays a crucial role in fringe projection profilometry. A class of variant shifting-phase coding method (VSPCM) has been proposed for high-speed 3D measurement. The three kinds of VSPCM include the inner shifting-phase method (ISPM), the intensity-coded method (ICM) and the modified Carré algorithm (MCA). These methods project only four patterns avoiding the need for extra images, yet achieve accuracy comparable to the classical three-frequency heterodyne method. In VSPCM, the shifting-phase, as a key code-word for phase unwrapping, is encoded as a variable value. In practice, the noise and the encoding of shifting-phase have varying degrees of impact on the performance of these methods. But the coded ranges of the shifting-phase were previouly empirical values. Besides, there are no studies related to these factors, and also a lack of comparative researches on such methods. This paper compares three kinds of VSPCM for the first time. We derive the noise error models for shifting-phase and wrapped phase in three methods and examine the impact of variant shifting-phase on fringe orders and wrapped phase in these methods. We find that the abnormal shifting-phase errors predominantly cause fringe orders errors. Fortunately, median filtering can effectively handle shifting-phase errors to ensure successful phase unwrapping. To improve their accuracy, we also deduce that the optimal shifting-phase encoding range is [-77°, 77°] for ISPM, and is [-61°, 61°] for ICM, and is [34°, 74°] for MCA. For wrapped phase errors, the distributions of ICM and MCA exhibit a U-shaped distribution, while ISPM demonstrates a uniform distribution. Based on theoretical analysis and experiment results, this paper gives recommendations for better use of these methods to boost their accuracy and offers valuable guidance for selecting an appropriate variant shifting-phase coding method under the specific measurement requirements.

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Section: Introductionmentioning

confidence: 99%

Comparative study of variant shifting-phase coding method based on noise error model

Wu,

Mu,

Cheng

et al. 2024

Meas. Sci. Technol.

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show abstract

“…In another aspect, due to the error caused by various factors, BA algorithm is often introduced in vision calibration to reduce the re-projection error and optimize the calibration parameters. The use of BA algorithm can achieve the jointly optimal estimate of the system parameters and 3D world coordinates of the feature points by minimizing the model of the error function [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

An Improved Projector Calibration Method by Phase Mapping Based on Fringe Projection Profilometry

Liu

Zhang

Yuan

et al. 2023

Sensors

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Aiming at the problem of the low accuracy of projector calibration in a structured light system, an improved projector calibration method is proposed in this paper. One of the key ideas is to estimate the sub-pixel coordinates in the projector image plane using local random sample consensus (RANSAC). A bundle adjustment (BA) algorithm is adopted to optimize the calibration parameters to further improve the accuracy and robustness of the projector calibration. After system calibration and epipolar rectification, the mapping relationship between the pixel coordinates and the absolute phase in the projector image plane is established by using cubic polynomial fitting, and the disparity is rapidly solved by using the mapping relationship, which not only ensures the measurement accuracy, but also improves the measurement efficiency. The experimental results demonstrated that the average re-projection error after optimization is reduced to 0.03 pixels, and the proposed method is suitable for high-speed 3D reconstruction without the time-consuming homogenous point searching.

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Efficient and accurate projector calibration method based on phase-shifting method with sinusoidal structured light

Li¹,

Zhong²,

Liu³

et al. 2023

Heliyon

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An improved projector calibration method for structured-light 3D measurement systems

Cited by 10 publications

References 31 publications

Comparative study of variant shifting-phase coding method based on noise error model

Comparative study of variant shifting-phase coding method based on noise error model

An Improved Projector Calibration Method by Phase Mapping Based on Fringe Projection Profilometry

Efficient and accurate projector calibration method based on phase-shifting method with sinusoidal structured light

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