Large depth-of-field 3D measurement with a microscopic structured-light system

Liu, Yanzhao; Fu, Yanjun; Zhuan, Yuhao; Zhou, Pengxu; Zhong, Kangping; Guan, Bingliang

doi:10.1016/j.optcom.2020.126540

Cited by 16 publications

(4 citation statements)

References 17 publications

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“…Considering the merits of the proposed telecentric structured light system method, we foresee the possibility of implementing this method into 3D shape measurements of microparts with a size on the order of millimeter used in microparts mechanical system. 24 However, a translation stage is required to accurately provide a calibration plate with known depth information to meet the requirements of high-accuracy measurement, so the calibration procedure is difficult beyond the laboratory environment. In the future, a flexible and automatic calibration method should be studied for different application scenarios.…”

Section: Discussionmentioning

confidence: 99%

Improved calibration method for a telecentric structured light system

Wang,

Chen

2023

Opt. Eng.

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Section: Discussionmentioning

confidence: 99%

Improved calibration method for a telecentric structured light system

Wang,

Chen

2023

Opt. Eng.

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“…So-called focus stacking (see Fig. 2), which is typically performed by using motorized or liquid lenses or by shifting the image sensor, 17,[20][21][22] maintains the luminous energy. However, while it does not negatively impact the detail sharpness, the refocusing mechanism leads to a reduced measurement speed and, when using special lenses, to a higher lens complexity.…”

Section: Chromatic Focus Stacking Approachmentioning

confidence: 99%

Depth-of-field extension in structured-light 3D surface imaging by fast chromatic focus stacking

Heist

Ramm

Mozaffari-Afshar³

et al. 2023

Dimensional Optical Metrology and Inspection for Practical Applications XII

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The depth range that can be captured by structured-light 3D sensors is limited by the depth of field of the lenses which are used. Focus stacking is a common approach to extend the depth of field. However, focus variation drastically reduces the measurement speed of pattern projection-based sensors, hindering their use in high-speed applications such as in-line process control. Moreover, the lenses’ complexity is increased by electromechanical components, e.g., when applying electronically tunable lenses. In this contribution, we introduce chromatic focus stacking, an approach that allows for a very fast focus change by designing the axial chromatic aberration of an objective lens in a manner that the depth-of-field regions of selected wavelengths adjoin each other. In order to experimentally evaluate our concept, we determine the distance-dependent 3D modulation transfer function at a tilted edge and present the 3D measurement of a printed circuit board with comparatively high structures.

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“…3D optical measurement is important in many application fields such as space observatory and reverse engineering [1][2][3]. Structured light methods perform well in reconstructing diffuse surfaces, but are usually unable to handle specular surfaces due to their strong reflectances.…”

Section: Introductionmentioning

confidence: 99%

A deep learning-based approach to solve the height-slope ambiguity in phase measuring deflectometry

Fan¹,

Ma²,

Li³

et al. 2023

Meas. Sci. Technol.

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Phase measuring deflectometry (PMD) shows excellent performance in measuring the shape of specular surfaces. However, the existing height-slope ambiguity affects the measurement of PMD. In this paper, we propose a deep learning-based method to solve the ambiguity and reconstruct the specular surface. A neural network was built to reconstruct the surface. A set of simulation surfaces were generated using two-dimensional Legendre polynomials to train and test the network. A spherical-shaped surface was reconstructed in a simulation to evaluate the validity of the proposed method and compare our method to the state-of-the-art method. Experimental results demonstrate a 35.88% improvement in this method’s accuracy. Our method provides a great improvement in measurement accuracy.

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Large depth-of-field 3D measurement with a microscopic structured-light system

Cited by 16 publications

References 17 publications

Improved calibration method for a telecentric structured light system

Improved calibration method for a telecentric structured light system

Depth-of-field extension in structured-light 3D surface imaging by fast chromatic focus stacking

A deep learning-based approach to solve the height-slope ambiguity in phase measuring deflectometry

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