Flexible Calibration of the Telecentric Vision Systems Using Only Planar Calibration Target

Li, Hai; Liao, Zhu; Cai, Weibin; Zhong, Yutao; Zhang, Xianmin

doi:10.1109/tim.2023.3332934

Cited by 3 publications

(1 citation statement)

References 37 publications

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“…Furthermore, owing to significant distortions within the depth of field of the imaging system, traditional camera calibration methods exhibit low efficiency and poor applicability for multiring imaging systems [27,28]. Therefore, the development of novel imaging system calibration methods is required [29]. The multi-ring system effectively reduces the deviations encountered during scanning, eliminating the need for complex light plane calibration [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Li,

Deng,

et al. 2024

Meas. Sci. Technol.

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Parts with a large depth-to-diameter ratio play a critical role in the military, aerospace, and automotive industries. However, accurately measuring their inner surface profile remians challenging owing to the lack of adequate and accurate sensors. We developed a multi-ring structured light system to obtain three-dimensional data of inner contours, such as inner diameters, which are crucial for ensuring component performance and safety. In this study, we proposed three simple yet effective techniques to improve the multi-ring beam structured measurement system. First, we designed a distortion correction method to calibrate the imaging system. Second, a two-step calibration approach was used to calibrate the multi-ring projection. Meanwhile, we benchmarked the effects of different light sources on image speckles. The calibration results demonstrated that the coefficient of determination (R-2) used for line fitting exceeded 0.999. Moreover, the measurement experimental results show that the uncertainty of less than 10 µm and the smallest measurable pipe inner diameter can reach 15 mm, demonstrating that our methods are promising for improving the accuracy of structured light optical sensing systems. This system satisfies the measurement requirements and can be immediately utilized to meet the high demand for inner contour measurements in industrial applications.

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Section: Introductionmentioning

confidence: 99%

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Li,

Deng,

et al. 2024

Meas. Sci. Technol.

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Machining Tool Wear Detection and Measurement Based on Edge Extraction and Subpixel Fitting

Chen,

2024

IEEE Trans. Instrum. Meas.

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Stereo Bi-Telecentric Phase-Measuring Deflectometry

Wang,

Fang

2024

Sensors

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Replacing the endocentric lenses in traditional Phase-Measuring Deflectometry (PMD) with bi-telecentric lenses can reduce the number of parameters to be optimized during the calibration process, which can effectively increase both measurement precision and efficiency. Consequently, the low distortion characteristics of bi-telecentric PMD contribute to improved measurement accuracy. However, the calibration of the extrinsic parameters of bi-telecentric lenses requires the help of a micro-positioning stage. Using a micro-positioning stage for the calibration of external parameters can result in an excessively cumbersome and time-consuming calibration process. Thus, this study proposes a holistic and flexible calibration solution for which only one flat mirror in three poses is needed. In order to obtain accurate measurement results, the calibration residuals are utilized to construct the inverse distortion map through bicubic Hermite interpolation in order to obtain accurate anchor positioning result. The calibrated stereo bi-telecentric PMD can achieve 3.5 μm (Peak-to-Valley value) accuracy within 100 mm (Width) × 100 mm (Height) × 200 mm (Depth) domain for various surfaces. This allows the obtaining of reliable measurement results without restricting the placement of the surface under test.

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Flexible Calibration of the Telecentric Vision Systems Using Only Planar Calibration Target

Cited by 3 publications

References 37 publications

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Accuracy improvement of a multi-ring beam structured inner surface measurement: via novel calibration methodology and light source optimization

Machining Tool Wear Detection and Measurement Based on Edge Extraction and Subpixel Fitting

Stereo Bi-Telecentric Phase-Measuring Deflectometry

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